fxEPA
             United States
             Environmental Protection
             Agency
             Robert S. Kerr Environmental Research
             Laboratory
             Ada OK 74820
EPA-600/2-80-073
April 1980
             Research and Development
Selected Irrigation
Return  Flow Quality
Abstracts 1978
             Eighth  Annual Issue

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                 RESEARCH REPORTING SERIES

 Research reports of the Office of Research and Development, U.S. Environmental
 Protection Agency, have been grouped into nine series. These nine broad cate-
 gories were established to facilitate further development and  application of en-
 vironmental technology. Elimination  of traditional grouping  was consciously
 planned to foster technology transfer and a maximum interface in related fields.
 The nine series are:

      1.   Environmental Health Effects Research
      2.   Environmental Protection Technology
      3.   Ecological Research
      4.   Environmental Monitoring
      5.   Socioeconomic Environmental Studies
      6.   Scientific and Technical Assessment Reports (STAR)
      7.   Interagency Energy-Environment Research and Development
      8.   "Special" Reports
      9.   Miscellaneous Reports

 This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
 NOLOGY series. This series describes research performed to  develop and dem-
 onstrate instrumentation, equipment,  and  methodology to repair or prevent en-
 vironmental degradation from point and non-point sources of pollution. This work
 provides the new or improved technology  required for the control and treatment
 of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                         EPA-600/2-80-073
                                         April 1980
         SELECTED IRRIGATION RETURN FLOW
             QUALITY ABSTRACTS 1978

               Eighth Annual Issue
                       by

              Gaylord V.  Skogerboe
                 Wynn R.  Walker
                Satyansu S.  Kundu
                  Mary Lindburg
            Colorado State University
          Fort Collins, Colorado  80523
               Grant No. R-800426
                 Project Officer

                  Alvin L. Wood
            Source Management Branch
Robert S. Kerr Environmental Research Laboratory
              Ada, Oklahoma  74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
       OFFICE OF RESEARCH AND DEVELOPMENT
      U.S. ENVIRONMENTAL PROTECTION AGENCY
              ADA, OKLAHOMA  74820

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                           DISCLAIMER


     This report has been reviewed by the Robert S. Kerr Environ-
mental Research Laboratory, U.S. Environmental Protection Agency/
and approved for publication.  Approval does not signify that the
contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or recommendation
for use.

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                           FOREWORD


     The Environmental Protection Agency was established to co-
ordinate administration of the major Federal programs designed
to protect the quality of our environment.

     An important part of the Agency's effort involves the
search for information about environmental problems, management
techniques and new technologies through which optimum use of the
Nation's land and water resources can be assured and the threat
pollution poses to the welfare of the American people can be
minimized.

     EPA's Office of Research and Development conducts this
search through a nationwide network of reserach facilities.  As
one of these facilities, the Robert S. Kerr Environmental Re-
search Laboratory is responsible for the management of programs
to: (a) investigate the nature, transport, fate and management
of pollutants in groundwater;  (b) develop and demonstrate methods
for treating wastewaters with soil and other natural systems;
(c) develop and demonstrate pollution control technologies for
irrigation return flows; (d) develop and demonstrate pollution
control technologies for animal production wastes;  (e) develop
and demonstrate technologies to prevent, control or abate pollu-
tion from the petroleum refining and petrochemical industries;
and (f) develop and demonstrate technologies to manage pollution
resulting from combinations of industrial wastewaters or
industrial/municipal wastewaters.

     This report provides a single source abstracted and indexed
reference of research on water quality problems of irrigation re-
turn flows and the potential technological solutions and institu-
tional constraints to solutions of those problems.  The sources
abstracted include coverage of work in the United States and
other parts of the world.  Current knowledge of related research
is essential if optimum use is to be made of our available re-
sources in developing reasonable, cost effective,  environmentally
sound solutions to the problems encountered in the control of
water quality in return flows from irrigated agriculture.


                                &Ufk...>C>0
                                William C.  Galegar
                                Director,  Robert S.  Kerr Environ-
                                  mental Research Laboratory
                              iii

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                            PREFACE
     The eighth annual issue of SELECTED IRRIGATION RETURN
FLOW QUALITY ABSTRACTS has been compiled from approximately 100
sources of material covering calendar year 1978.  This compila-
tion has attempted to include technological and institutional
articles that would be pertinent to action programs regarding
the control of water quality degradation resulting from irrigated
agriculture.

     The state-of-the-art report, "Characteristics and Pollution
Problems of Irrigation Return Flow," prepared by the Utah State
University Foundation, contains a bibliography of articles perti-
nent to Irrigation Return Flow Quality through 1967.  The first
annual issue Of SELECTED IRRIGATION RETURN FLOW QUALITY ABSTRACTS
listed publications appearing in calendar years 1968 and 1969,
while the second annual issue listed publications appearing in
calendar years of 1970 and 1971, the third annual issue contained
abstracts of articles and reports published during calendar
years 1972 and 1973, and the fourth, fifth, sixth and seventh
annual issues contained abstracts of 1974, 1975, 1976 and 1977
publications.  The eighth annual issue contains 787 abstracts
of documents published during calendar year 1978.  The abstracts
have been placed into sections according to the category and
subgroup classifications used by the Water Resources Scientific
Information Center (WRSIC)  as published in the report, "Water
Resources Thesaurus."  The abstracts have been forwarded to
WRSIC for inclusion in their bi-monthly publication, "Selected
Water Resources Abstracts."
                               xv

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                           ABSTRACT
     Research related to the quality of irrigation return flow
is being conducted at numerous institutions throughout the
western United States.  Related work is also underway at other
institutions in the United States, as well as other portions of
the world.  Approximately 100 sources of material have been
searched for articles pertinent to the Irrigated Crop Production
research and development program.  These articles describe water
quality problems resulting from irrigated agriculture, potential
technological solutions for controlling return flows, recent
research pertinent to return flow investigations, and literature
associated with institutional constraints in irrigation return
flow quality control.

     The first annual issue of SELECTED IRRIGATION RETURN FLOW
QUALITY ABSTRACTS covered publications printed in 1968 and 1969,
while the second annual issue lists publications printed in 1970
and 1971, the third annual issue covers calendar years 1972 and
1973, and the fourth, fifth, sixth and seventh annual issues
cover literature published in 1974, 1975, 1976 and 1977.  This
annual issue lists publications printed in 1978.  This report
was submitted in fulfillment of Grant No. R-800426 under the
sponsorship of the Office of Research and Development, U.S.
Environmental Protection Agency.

     Key Words:  Fertilizers, Irrigated land. Irrigation systems,
Irrigation water, Nitrates, Phosphates, Return flow, Salinity,
Water pollution effects, Water pollution sources, Water quality
control.

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                       TABLE OF CONTENTS
Foreword .  . . ,
Preface  .  . . ,
Abstract .  . . ,
Acknowledgments
                   - General  (Group 02A)  	
                   - Precipitation  (Group 02B)  	
                   - Snow, Ice, and Frost  (Group  02C).  .  .
                   - Evaporation and Transpiration  (Group

                   - Streamflow and Runoff  (Group 02E)  .  .
                   - Groundwater (Group 02F)  	
                   - Water in Soils (Group  02G)	
                   - Lakes (Group 02H)  	
                   - Water and Plants  (Group  021)	
                   - Erosion and Sedimentation  (Group 02J)
                   - Chemical Processes (Group  02K).  .  .  .
                    AUGMENTATION AND CONSERVATION -
                   Improvement (Group  03B)  	
                    AUGMENTATION AND CONSERVATION -
                    of Impaired Quality (Group  03C).  .  .  .
                    AUGMENTATION AND CONSERVATION -
                    in Domestic and Municipal Use (Group
    I  WATER CYCLE
   II  WATER CYCLE
  III  WATER CYCLE
   IV  WATER CYCLE
       02D) ....
    V  WATER CYCLE
   VI  WATER CYCLE
  VII  WATER CYCLE
 VIII  WATER CYCLE
   IX  WATER CYCLE
    X  WATER CYCLE
   XI  WATER CYCLE
  XII  WATER SUPPLY
       Water Yield
 XIII  WATER SUPPLY
       Use of Water
  XIV  WATER SUPPLY
       Conservation
       03D) ....
   XV  WATER SUPPLY AUGMENTATION AND CONSERVATION - Con-
       servation in Agriculture (Group 03F)	
  XVI  WATER QUANTITY MANAGEMENT AND CONTROL - Control of
       Water on the Surface (Group 04A)	
 XVII  WATER QUANTITY MANAGEMENT AND CONTROL - Ground-
       water Management (Group 04B)	
XVIII  WATER QUANTITY MANAGEMENT AND CONTROL - Effect on
       Water of Man's Nonwater Activities  (Group 04C). .  .
  XIX  WATER QUANTITY MANAGEMENT AND CONTROL - Watershed
       Protection  (Group 04D)	
   XX  WATER QUALITY MANAGEMENT AND PROTECTION - Identifi-
       cation of Pollutants (Group 05A)	
  XXI  WATER QUALITY MANAGEMENT AND PROTECTION - Sources
       and Fate of Pollution (Group 05B) 	
 XXII  WATER QUALITY MANAGEMENT AND PROTECTION - Effects
       of Pollution (Group 05C)	
XXIII  WATER QUALITY MANAGEMENT AND PROTECTION - Waste
       Treatment Processes (Group 05D) 	
 XXIV  WATER QUALITY MANAGEMENT AND PROTECTION - Water
       Quality Control (Group 05G) 	 	
111
 iv
  v
 ix

  1
  6
  7

  8
 12
 16
 27
 58
 59
 74
 83

110

111
                                                             114

                                                             115

                                                             156

                                                             162

                                                             168

                                                             169

                                                             172

                                                             180

                                                             205

                                                             208

                                                             209
                              vii

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    XXV  WATER RESOURCES AND PLANNING - Techniques of
         Planning (Group 06A)	235
   XXVI  WATER RESOURCES PLANNING - Evaluation Process
         (Group 06B)	241
  XXVII  WATER RESOURCES PLANNING - Cost Allocation, Cost
         Sharing, Pricing/Repayment (Group 06C)	248
 XXVIII  WATER RESOURCES PLANNING - Water Demand  (Group
         06D)	249
   XXIX  WATER RESOURCES PLANNING - Water Law and
         Institutions (Group 06E)	250
    XXX  WATER RESOURCES PLANNING - Ecological Impact of
         Water Development (Group 06G)	256
   XXXI  RESOURCES DATA - Network Design (Group 07A) .... 258
  XXXII  RESOURCES DATA - Data Acquisition (Group 07B)  . .  . 259
 XXXIII  RESOURCES DATA - Evaluation, Processing and
         Publication (Group 07C) 	 271
  XXXIV  ENGINEERING WORKS - Structures (Group 08A)	 272
   XXXV  ENGINEERING WORKS - Hydraulics (Group 08B)	 273
  XXXVI  ENGINEERING WORKS - Hydraulic Machinery  (Group
         08C)	278
 XXXVII  ENGINEERING WORKS - Rock Mechanics and Geology
         (Group 08E)	279
XXXVIII  ENGINEERING WORKS - Materials (Group 08G) 	 280
  XXXIX  MANPOWER, GRANTS, AND FACILITIES - Education -
         Extramural (Group 09A)	281
     XL  SCIENTIFIC AND TECHNICAL INFORMATION - Acquisition
         and Processing (Group 10A)	282
    XLI  SCIENTIFIC AND TECHNICAL INFORMATION - Secondary
         Publication and Distribution (Group IOC)	283
   XLII  AUTHOR INDEX	285
  XLIII  SUBJECT INDEX	305
                              viii

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                        ACKNOWLEDGMENTS
     The excellent cooperation of the reading room staff at the
Engineering Research Center and the library staff at Colorado
State University has been very important in accomplishing the
work reported herein.

     The scope of this literature abstracting effort has been
delineated jointly by the senior author and project officer,
Mr. Alvin L. Wood, Source Management Branch, Robert S. Kerr
Environmental Research Laboratory, Environmental Protection
Agency, Ada, Oklahoma.  The cooperative efforts of the Project
Officer in meeting with project personnel and reviewing the
abstracting process have been very helpful and are sincerely
appreciated.
                               ix

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                                  SECTION I

                                 WATER CYCLE

                             GENERAL (GROUP 02A)


78:02A-001
A METHODOLOGY FOR TESTING THE ACCURACY OF YIELD PREDICTIONS FROM WEATHER-YIELD
REGRESSION MODELS FOR CORN,
Nelson, W.L., and Dale, R.F.
Purdue University, West Lafayette, Indiana, Department of Agronomy.
Agronomy Journal, Vol. 70, No. 5, p 734-740, September-October, 1978.  5 tab,
21 ref, 2 equ.

Descriptors:  Statistical models, Technology, Weather data, Regression analysis,
Corn (field), Nitrogen, Indiana, Crop production.

Analysis of variance  (ANOVA) techniques were used to evaluate the accuracy of
yield predictions for corn in Indiana counties with four statistical models:
1)  Thompson approach, 2)  modified Thompson approach with a nitrogen technology
term, 3)  a 1974 model by Leeper, Runge, and Walker and 4)  a 1975 model by Dale
and Hodges.  For models 1) , 2), and 4), separate versions were developed with
the particular series of weather and corn yield data for each county.  All models
were used to predict yearly average corn yields for a county with data not used
to fit the regression coefficients.  A significant difference among models was
detected by the ANOVA.  Multiple comparison tests indicated that regression
models 2), 3), and 4) were more accurate than model 1).  This result was attributed
mainly to the handling of technology or the weather-technology interaction effects
on corn yields.  The trend variables used in model 1) acted to confound weather
and technology effects and create unstable regression models.  Although the direct
application of the results of this study is limited to Indiana, the methodology
for testing the accuracy of yield predictions is believed to have universal
application.


78:02A-002
CALIBRATION OF HYDROLOGICAL MODEL USING OPTIMIZATION TECHNIQUE,
Manley, R.E.
Severn-Trent Water Authority, Birmingham, England.
Journal of the Hydraulics Division, Proceedings of the American Society of Civil
Engineers, Vol. 104, No. HY2, p 189-202, February, 1978.  4 fig, 3 tab, 20 ref.

Descriptors:  *Optimization, *Simulation analysis, *Computer models, *Mathematical
models, Digital computers, Droughts, Algorithms, Wave velocity, Model studies,
Water resources.

Computer-based mathematical models that simulate the response of a catchment
to climatic variables have been available for more than a decade.  One of the
drawbacks to the use of these models has been the difficulty of calibrating them
to a particular catchment.  The catchment model HYSIM has all but four of its
parameters estimated  from catchment details or hydrograph analysis; the four
are calibrated using  a modified version of the Rosenbrock algorithm.  The complete
model occupies about  12K words  (36K bytes) of computer core storage.  HYSIM was
used to produce a 44-year record for a river in England extensively used for
water supply.  Despite the  fact that only a limited amount of data was available,
the extended record has proven adequate for water resources analysis.


78:02A-003
SENSITIVITY OF GROUNDWATER MODELS WITH RESPECT TO VARIATIONS IN TRANSMISSIVITY
AND STORAGE,
McElwee, C.D., and Yukler, M.A.
Geological Survey, Lawrence, Kansas.
Water Resources Research, Vol.  14, No. 3, p 451-459, June, 1978.  14 fig, 15 ref.

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 Descriptors:   *Aquifers,  *Groundwater,  *Groundwater  movement,  *Model  studies,
 Transmissivity,  Storage  coefficient, Drawdown,  Hydraulic  conductivity, Analytical
 techniques, Sensitivity  analysis,  Sensitivity coefficient.

 Sensitivity analysis  is  the  study  of a  system's response  to  various disturbances.
 In  this  study, disturbances  of  aquifer  parameters were  considered.  In the  simu-
 lation of  an  aquifer,  the investigator  must  establish tolerance within which the
 parameters of the physical system  may vary without appreciably affectinq  the model
 results.   By  means of  a  first-order sensitivity formalism, it was shown how to
 evaluate the  perturbed hydraulic head for a  small change  in  aquifer parameter.
 An  expression for the  sensitivity  coefficient was obtained in this study  by taking
 the partial derivative of the flow equation  with respect  to  a particular  parameter.
 The sensitivity  coefficient  was evaluated either analytically or by numerical
 techniques for some common models.  The sensitivity  formalism was applied to the
 Theis equation to study  the  general behavior of sensitivity  coefficients  and to
 determine  the range of validity of the  first-order sensitivity formalism.   The
 formalism  also was applied to one- and  two-dimensional  numerical models to  see
 the effect of barrier  and constant head boundaries.  The  perturbed hydraulic head
 was obtained  for a change of transmissivity  (T)  and  storage  coefficient (S) by
 applying the  first-order  sensitivity formalism.  This procedure should be a
 valuable tool in calibrating models or  establishing  tolerances on T and S for a
 given acceptable error in hydraulic head.  In general,  a  + or - 20% deviation
 in  T or S  may be handled  adequately by  the first-order  formalism discussed  in this
 work.


 78:02A-OQ4
 MODELING NITROGEN MOVEMENT IN AGRICULTURAL WATERSHEDS,
 Campbell,  K.L., and Sinai, G.
 Florida University, Gainesville, Department  of  Agricultural  Engineering.
 Paper No.  78-2071, Presented at the 1978 Summer Meeting of the American Society
 of  Agricultural Engineers, June 27-30,  1978, Logan,  Utah, 15 p.  1 fig, 22  ref.

 Descriptors:   Nitrogen, Water quality,  Water quality control, Model studies,
 Simulation analysis, Pollutants, Pollution abatement, Agricultural watersheds,
 Hydrology, Nutrient removal.

 Techniques were developed to simulate nitrogen movement through agricultural
 watersheds.   The USDAHL-74 (USDA-ARS Tech. Bui.  No.  1518) model of watershed
 hydrology was  used to  provide the  hydrologic information  required to model
 nitrogen movement.  The ACTMO (agricultural  chemical transport model USDA, ARS-
 H-3) nitrate  model was used  as a framework for  the nitrogen model.  Important
 components to be added to the ACTMO model are discussed.


 78;02A-005
 A QUASI-LINEAR SPATIALLY  DISTRIBUTED CELL MODEL  FOR  THE SURFACE RUNOFF SYSTEM,
 Diskin, M.H., and Simpson, E.S.
 Technion-Israel Institute of Technology, Haifa,  Israel, Faculty of Civil
 Engineering.
Water Resources Bulletin, Vol.  14, No.  4, p  903-918, August,  1978.  7 fig,  3 tab,
 10  ref.

 Descriptors:   *Surface runoff,  *Watersheds (basins) , *Model studies, Precipitation
 (atmospheric), Precipitation excess, Excessive precipitation, Hydrographs,
Analytical'techniques, Synthetic hydrology, Hydrology.

The paper presented a spatially distributed model consisting of cells that are
 interconnected in a pattern  similar to  the major drainage network of the water-
 shed.   Each cell receives as input the  rainfall  excess for the area represented
by  the cell as well as inflows  from cells located upstream.   Outflow from the
cell is derived by routing the  total input through the cell assuming it to be a
 linear reservoir during the  storm.  The time constant of  the cell, however,  was
 allowed to vary from storm so that the model may be described as a quasi-linear
model.   The model was tested with rainfall excess and direct surface runoff data
available for a medium size watershed with satisfactory results.   The time
constant was  found to be related to the rainfall excess of the storms studied,
 its value decreasing with the increase  in the total rainfall excess.

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78:02A-006
AN ADAPTIVE ALGORITHM FOR ANALYZING SHORT-TERM STRUCTURAL AND PARAMETER CHANGES
IN HYDROLOGIC PREDICTION MODELS,
Wood, E.F., and Szollosi-Nagy, A.
Princeton University, New Jersey, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 4, p 577-581, August, 1978.  7 fig, 34 ref,
1 append.

Descriptors:  *Rainfall-runoff relationships, *Simulation analysis, *Forecasting,
*Input-output analysis, *Algorithms, *State space formulation, Environmental
effects, Kalman filters, Ombone River Basin (Italy), Noise covariances.

An adaptive unbiased recursive prediction algorithm, based on the state space
description of hydrologic systems, is discussed.  Discrete linear systems with
white Gaussian disturbances are considered.  The algorithm allows for short-term
structural and parameter changes due to random environmental effects.  A pre-
diction model is set up from a representation of the rainfall-runoff processes
with the unknown parameters modeled by a random walk.  The predictions are ob-
tained by the use of linear Kalman filters where the unknown noise covariance
matrices are also adaptively estimated.  The behavior of the adaptive prediction
algorithm is illustrated by a real-world example taken from rainfall-runoff
flood forecasting.


78:02A-OQ7
CLIMATE, SOIL, AND^VEGETATION 7.  A DERIVED DISTRIBUTION OF ANNUAL WATER YIELD,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 765-776, October, 1978.  10 fig,
3 tab, 13 ref, 35 equ.

Descriptors:  Water yield, Water balance. Soil-water-plant relationships, Soil
moisture movement, Precipitation, Storm runoff, Infiltration, Climatic data,
Mathematical models, Stochastic processes.

The average annual soil moisture balance, as derived from the mechanics of
storm and intersto.rm soil moisture movement and from the statistics of the
climatic variables, were used to define the average annual soil moisture.  This
soil moisture was used in the equation for average annual yield to give a first-
order approximation of the annual precipitation yield function.  This function
was used to transform the cumulative distribution function (cdf) of annual
precipitation into the cdf of annual yield, and application was made in a sub-
humid and in an arid climate.  The derived yield frequency function is seen to be
sensitive to the soil and vegetal properties.  Proper selection of these para-
meters brought close agreement-with observed streamflow-frequency and suggested
the model's utility for parameterizing drainage basins with respect to effective
average soil and vegetal properties.


78:02A-008
CLIMATE, SOIL, AND VEGETATION 6.  DYNAMICS OF THE ANNUAL WATER BALANCE,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 749-764, October, 1978.  11 fig,
4 tab, 20 ref, 74 equ'.

Descriptors:  Water balance, Soil-water-plant relationships, Precipitation
(atmospheric), Evapotranspiration, Surface runoff, Groundwater, Climatic data,
Moisture deficit, Mathematical models.

Mass conservation was employed to express the natural water balance of climate-
soil-jvegetation systems in terms of the average annual values of precipitation,
evapotranspiration, surface runoff, and groundwater runoff as derived from the
probability distributions of storm properties and from the physics of the
appropriate storm and interstorm soil moisture fluxes.  The resulting conserva-
tion equation was used to define the diroensionless parameters governing the
dynamic similarity of the annual water balance.  An asymptotic analysis of this
water balance equation yielded a set of rational criteria for the classification
of climate-soil-vegetation systems.  Sensitivity with respect to the primary
climate, soil, and vegetal parameters demonstrated that qualitative changes in

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water balance behavior are primarily dependent upon the exfiltration
effectiveness of the soil.  A natural selection hypothesis was presented which
specified the stable vegetation density and the plant coefficient for a given
climate-soil system in which water and not nutrition or light was limiting.


7&:02A-009
CLIMATE, SOIL, AND VEGETATION 5.  A DERIVED DISTRIBUTION OF STORM SURFACE
RUNOFF,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 741-748, October, 1978.  6 fig,
2 tab, 11 ref, 76 equ.

Descriptors:  Storm runoff, Climatic data, Soil properties, Vegetation, Rainfall-
runoff relationships, Soil moisture, Rainfall intensity, Infiltration, Flood
discharge, Mathematical models.

The Philip infiltration equation was integrated over the duration of a rainstorm
of uniform intensity to give the depth of point surface runoff from such an
event on a natural surface in terms of random variables defining the initial
soil moisture, the rainfall intensity, and the storm duration.  In a zeroth-
order approximation the initial soil moisture was fixed at its climatic space
and time average, whereupon by using exponential probability density functions
for storm intensity and duration, the probability density function of point
storm rainfall excess was derived.  This distribution was used to define the
annual average depth of point surface runoff and to derive the flood volume fre-
quency relation, both in terms of a set of physically meaningful climate-soil
parameters.


78:02A-010
HYDROLOGIC MODELING OF SMALL WATERSHEDS IN ASAE MONOGRAPH,
Haan, C.T.
Oklahoma State University, Stillwater, Department of Agricultural Engineering.
Paper No. 78-2588, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 5 p.

Descriptors:  Hydrologic cycle, Small watersheds, Model studies, Hydrology,
Stochastic processes, Hydrologic properties, Groundwater, Soil water movement,
Evapotranspiration, Soil erosion.

This monograph has 13 chapters devoted to modeling of the hydrplogic cycle on
small watersheds.  Primary emphasis is on basic approaches to modeling the
various parts of the hydrologic cycle, on combining component models into
hydrologic models and on selecting and testing hydrologic models.


78:02A-011
SIMULATED STREAMFLOW RESPONSE TO POSSIBLE DIFFERENCES IN TRANSPIRATION AMONG
SPECIES OF HARDWOOD TREES,
Federer, C.A., and Lash, D.
Northeastern Forest Experiment Station, United States Department of Agriculture,
Forest Service, Durham, New Hampshire  03824.
Water Resources Research, Vol. 14, No. 6, p 1089-1097, December, 1978.  8 fig,
4 tab, 17 ref.

Descriptors:  Streamflow, Transpiration, Hydrologic cycle, Model studies,
Simulation analysis, Hardwood, Forest watersheds, Watershed management, Equation,
Evapotranspiration, Hydrologic.

Possible differences in transpiration among species of hardwood trees were
simulated in a hydrologic model, called Brook, to estimate the effects of these
differences on monthly and annual streamflow.  Brook is a deterministic, lumped-
parameter model that simulated streamflow from small, forested watersheds in
the eastern United States.  The model uses only daily mean temperature and daily
precipitation as input.  A 4-week difference in timing of leaf-development in
spring or color change in autumn caused differences of 10-60 mm in simulated
annual streamflow.  When daily transpiration varied by 20%, as it might with

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differences in leaf diffusive resistance among species, differences in simulated
streamflow ranged from 15 to 120 mm annually.  Differences in root distribution
with depth can affect the availability of soil water; varying this availability
caused differences in simulated streamflow of 15-60 mm.  In all cases the smaller
differences occurred when the soil was dry at the times of differing transpiration.
On a deep residual soil the differences in streamflow were spread through the year,
but on a shallow till soil the differences were restricted to the months in which
there were changes in transpiration.  Differences in response among 15 degrees
north-facing and 15 degrees south-facing slopes and a horizontal surface were
minor.

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                                  SECTION  II


                                 WATER CYCLE

                          PRECIPITATION  (GROUP 02B)


78:028-001
CLIMATE, SOIL, AND VEGETATION 2. THE DISTRIBUTION OF ANNUAL PRECIPITATION DERIVED
FROM OBSERVED STORM SEQUENCES,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 713-721, October, 1978.  12 fig,
1 tab, 11 ref, 54 egu.

Descriptors:  Precipitation (atmospheric), Distribution, Storms, Rainfall, Statis-
tical methods, Probability, Stochastic processes.

Point precipitation was represented by Poisson arrivals of rectangular intensity
pulses that have random depth and duration.  By assuming the storm depths to
be independent and identically gamma distributed, the cumulative distribution
function for normalized annual precipitation was derived in terms of two para-
meters of the storm sequence,  the mean number of storms per year and the order
of the gamma distribution.  In comparison with long-term observations in a sub-
humid and an arid climate it was demonstrated that when working with only 5 years
of storm observations this method tends to improve the estimate of the variance
of the distribution of the normalized annual values over that obtained by con-
ventional hydrologic methods which utilize only the observed annual totals.

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                                 SECTION III


                                 WATER CYCLE

                      SNOW, ICE, AND FROST (GROUP 02C)


78:020-001
WATER REDISTRIBUTION IN PARTIALLY FROZEN, SATURATED SILT UNDER SEVERAL
TEMPERATURE GRADIENTS AND OVERBURDEN LOADS,
Loch, J.P.G., and Kay, B.D.
Guelph University, Ontario, Department of Land Resources Science.
Soil Science Society of America Journal, Vol. 42, No. 3, p 400-406, May-June,
1978.  7 fig, 2 tab, 17 ref.

Descriptors:  *New Hampshire, *Freezing, *Soil water, *Crystal growth, *Frost
heaving, *Cryogenics, Thermocline, Saturated flow, Model studies, Gamma
scanning system.

The flux of water and the resultant formation of discrete ice lenses were studied
in samples of New Hampshire silt which were saturated and then frozen under
different temperature gradients and overburden pressures.  A dual energy gamma
scanning system was employed to locate the position of the growing ice lens rela-
tive to the freezing front.  Parameters controlling water flow and the location
of the ice lenses were employed to evaluate theories that have been proposed to
describe the mechanisms of ice lens formation.  The capillary theory was employed
to locate the freezing front.  However, the ice lenses were found to be located
0.2-0.4 cm behind the freezing front, which is inconsistent with the location
of the ice lenses predicted by the capillary theory.  Neither the hydrodynamic
theory nor the secondary frost heaving theory account for the redistribution of
overburden pressure between soil particles, ice, and water.  These theories
cannot be employed to predict the location of the ice lens relative to the
freezing front until overburden pressure effects are incorporated into the theory.

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                                  SECTION  IV


                                 WATER CYCLE

                  EVAPORATION AND TRANSPIRATION  (GROUP 02D)


 78:020-001
 THE DISHONEST METHOD IN STREAM TEMPERATURE MODELING,
 Morse, W.L.
 Bonneville Power Administration, Portland, Oregon.
 Water Resources Research, Vol. 14, No. 1, p  45-51, February, 1978.  1 tab, 18 ref.

 Descriptors:  *Water temperature, *Streams,  *Model studies, *Mathematical models,
 Stochastic processes, Mathematics, Statistics, Solar radiation. Hydrology,
 Heat transfer.

 The unidimensional form of the thermal energy conservation principle as a quasi-
 linear partial differential equation  (PDE) has been shown accurate for point
 temperature forecasts on completely mixed streams and river-run reservoir systems.
 Two methods of solution were presented which lead to a unique solution.  Yet this
 nonrandom solution was contrary to the behavior of nature, and so a philosophic
 change was introduced.  From the PDE  subsidiary differential system a stochastic
 differential equation (SDE) was obtained with random forcing function from the
 meteorologic and forebay-depth analyses.  With random intial conditions (time-
 averaged components of the in situ water temperature vector), the SDE was recasted
 as a random nonlinear Volterra integral equation  (RIE).  Then a solution to the
 random-initial-conditions RIE (fixed  points of the expectations) by the so-called
 dishonest method was compared with a  solution obtained by repetitively solving
 the PDE as a random equation (expectations of the fixed points).  Of course,
 these solutions, obtained by "dishonest and honest" methods, are not necessarily
 unique, but they may be sufficiently  close in some sense.  Hence, proper inter-
 pretation and use of this RIE model would enable water resource planners to
 determine economically stream temperatures in probability during critical climatic
 or river flow conditions.  And then intelligent planning and scheduling could
 avoid some catastrophic aquatic event which might occur as a result of extreme
 water temperatures.


 78:020-002
 EVALUATION OF EVAPORATION FROM LAKE ONTARIO DURING IFYGL BY A MODIFIED MASS
 TRANSFER EQUATION,
 Phillips, D.W.
 Atmospheric Environment Service, Downsview, Ontario, Hydrometeorology and Marine
 Applications Division.
 Water Resources Research, Vol.  14, No. 2, p 197-205, April, 1978.  4 fig,  4 tab,
 28 ref.

 Descriptors:  *Evaporatlon, *Lake Ontario, *Great Lakes, *International field
 year, *Lake Hefner, Turbulent energy  flux, Multi-regression equations,  Hydrologic
 budget, Stability, Meteorology.

 Daily evaporation from Lake Ontario during the International Field Year for the
 Great Lakes (.April, 1972 to March, 1973}  was computed by a modified/mass transfer
 technique.  Turbulent energy flux was calculated by using upwind land station
 data and the surface water temperature at 88 grid points on the lake.  Wind
 speed and humidity at each grid point were determined through multi-degression
 equations that took into account stability, fetch, and water temperature..  Daily,
monthly, and annual evaporation amounts obtained by this study were compared
 to amounts obtained by conventional mass transfer, energy balance, and terrestrial
water budget methods, discrepancies in the results of the various approaches were
 examined and discussed.

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78:020-003
ESTIMATING EVAPOTRANSPIRATION RATES FOR CORN IN DELAWARE,
Ritter, W.F., Williams, T.H., and Eastburn, R.P.
Delaware University, Newark, Department of Agricultural Engineering.
Paper No. 78-2029, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 27 p.  17 fig, 1 tab,
11 ref.

Descriptors:  Evapotranspiration, Estimating, Humid climates, Corn  (field),
Meteorological data, Growth stages, Consumptive use, Delaware.

The Jensen-Haise, Penman, pan evaporation and Thornthwaite methods were used
to predict evapotranspiration.  All methods underestimated the measured peak ET
rates.  The critical moisture period for corn was found to be from the 14th leaf
stage to beginning dent.


78:02D-004
EVAPOTRANSPIRATION FROM WATER HYACINTH IN TEXAS RESERVOIRS,
Benton, A.R., Jr., James, W.P., and Rouse, J.W.
Texas A * M University, College Station, Department of Civil Engineering.
Water Resources Bulletin, Vol. 14, No. 4, p 919-930, August, 1978.  3 fig, 3 tab,
21 ref.

Descriptors:  *Evapotranspiration, *Water hyacinth, *Reservoirs, *Water loss,
*Texas, *Texas Water plan. Floating plants, Vegetation effects, Aquatic plant
control, Aquatic weeds.

Water hyacinth, an attractive, floating aquatic plant, poses a substantial
threat of unanticipated water loss from Texas reservoirs.  A mature plant will
lose about three times as much water through evapotranspiration as is lost from
evaporation of an equivalent area of open water.  The reservoirs of east and
southeast Texas, which comprise the bulk of the state's existing and planned
water storage capacity, seem likely to suffer a 20% average surface infestation
of water hyacinth.  A coverage that great will result in a yearly net loss of
over 2,000,000 acre-feet of impounded water, based on present water development
plans for the state.  This would amount to nearly 20% of the anticipated yield
from the reservoirs affected.  An effective aquatic plant control program could
head off the threat of this significant water loss.


78:02D-005
CLIMATE, SOIL, AND VEGETATION 4.  THE EXPECTED VALUE OF ANNUAL EVAPOTRANSPIRATION,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 731-739, October, 1978.  6 fig,
24 ref, 53 equ.

Descriptors:  Evapotranspiration, Water balance, Infiltration, Soil moisture
movement, Climatic data, Soil properties, Vegetation, Mathematical models,
Surface runoff.

The depth of interstorm evapotranspiration from natural surfaces was composed
(by proportion to vegetal canopy density) of evaporation from bare soil and
transpiration from vegetation.  The former was obtained in terms of random
variables describing initial soil moisture, time between storms, and potential
rate of evapotranspiration from an exfiltration analogy to the Philip infiltra-
tion equation modified to incorporate moisture extraction by plant roots.  The
latter was assumed to occur at the potential rate for natural vegetal systems.
In a zeroth-order approximation the initial soil moisture was fixed at its cli-
matic space and time average whereby using an exponential distribution of time
between storms and a constant potential rate of evapotranspiration the expected
value of interstorm evapotranspiration was derived.  This mean value was used
to obtain the annual average point- evapotranspiration as a fraction of the
potential value and as a function of dimensionless parameters defining the
climate-soil-vegetation system.

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 78:020-006
 A COMPARISON OF TWO FORMULA TYPES FOR CALCULATING LONG-WAVE RADIATION FROM THE
 ATMOSPHERE,
 Aase, J.K., and Idso, S.B.
 Northern Plains Soil and Water Research Center, Sidney, Montana.
 Water Resources Research, Vol. 14, No. 4, p 623-625, August, 1978.  1 fig, 1 tab,
 14 ref, 3 equ.

 Descriptors:  Radiation, Thermal radiation, Solar radiation, Air temperature,
 Humidity, Vapor pressure, Estimating equations.

 Measurements of long-wave radiation at Sidney, Montana, indicated that both an
 analytically derived equation and an empirically derived equation for clear-sky
 conditions adequately predict the long-wave radiation flux at that site for
 screen level air temperatures above 0°C.  However, for air temperatures below
 0°C, the analytical equation always underestimated the true radiation, while the
 empirical equation just slightly underestimated it, then match it, and then over-
 estimated it, as air temperature decreased from 0°C to -37°C.  These discrepancies
 in the below 0°C temperature regime indicated that the equations might need some
 modification to conform more closely to reality for low-temperature conditions.


 78:020-007
 THE ROLE OF EVAPOTRANSPIRATION MODELS IN IRRIGATION SCHEDULING,
 Jensen, M.E., and Wright, J.L.
 Snake River Conservation Research Center, United States Department of Agriculture-
 Agricultural Research Service, Kimberly, Idaho.
 Transactions of the American Society of Agricultural Engineers, Special Edition,
 Vol. 21 SW, No. 1, p 82-87, February 20, 1978.  4 fig, 2 tab, 25 ref, 3 equ.

 Descriptors:  Scheduling, Irrigation, Evapotranspiration, Model studies, Soil
 moisture, Statistical methods.

 Most evapotranspiration (ET) models are based on physical principles controlling
 evaporation and the conservation of mass and energy, and use daily climatic data.
 ET models coupled with irrigation models are valuable tools because they enable
 trained and experienced irrigation specialists to provide irrigation scheduling
 services at a reasonable cost.  Estimated standard deviations of mean daily ET
 for 1- to 30-day periods at Akron, Colorado; Davis, California; Kimberly, Idaho;
 and Lompoc, California varied from 0.9 to 1.3 mm/day and it decreased to 0.4 to
 0.7 mm/day for 15- to 30-day periods.  Standard errors of ET estimates with a
 combination equation based on 243 days of data from Kimberly, Idaho were normally
 distributed and for daily values was 1.0 mm/day.  This parameter decreased in-
 versely with the square root of the number of days for up to 30 days and was
 similar to those reported for other areas using models that operate on daily
 climatic data.  A summary of factors affecting confidence levels in irrigation
 scheduling was presented along with the expected standard deviations.  Generally,
 the error in measuring soil moisture was generally smaller than estimated ET
 and irrigation application errors.


 78:020-008
 DEVELOPMENT AND EVALUATION OF EVAPOTRANSPIRATION MODELS FOR IRRIGATION SCHEDULING,
Wright, J.L., and Jensen, M.E.
 Snake River Conservation Research Center, Kimberly, Idaho.
 Transactions of the American Society of Agricultural Engineers, Special Edition,
 Vol. 21SW, No.' 1,  p 99-91, 96, February 20, 1978.  6 fig, 1 tab, 7 ref, 4 equ.

 Descriptors:  Evapotranspiration, Model studies, Scheduling, Irrigation,
 Lysimeters, Soil water.

 Evapotranspiration (ET)  data for irrigated crops in southern Idaho were used to
 develop relationships for estimating net radiation and potential ET for the
 USDA-ARS Computerized Irrigation Scheduling Program.  ET estimated with the
 initial relationships compared well with recent measurements obtained with two
 sensitive weighing lysimeters.  The average daily measured ET for alfalfa for
 128 days when there was full cover was 7.23 mm, while the average daily estimated
 ET was 7.15 mm.  Crop curve relationships were developed from the ET results for
 snap beans CPhaseolus vulgaris L.).   The depletion of soil water was predicted


                                      10

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for two years of irrigated beans with the scheduling program using the improved
crop curves and compared with the measured as a test of its  performance.   The
standard deviation of the difference between predicted and measured was about
0.95 mm/day from planting until harvest.   The results also demonstrated the
importance of obtaining representative meteorological data for irrigation
scheduling.
                                      11

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                                  SECTION V


                                 WATER CYCLE

                      STREAMFLOW AND RUNOFF  (GROUP 02E)


78:02E-001
SOME PROPERTIES OF VARIANCE REDUCTION TECHNIQUES WHERE HYDROLOGICAL EXTREMES
ARE ESTIMATED BY MONTE CARLO SIMULATION,
Moore, R.J., and Clarke, R.T.
Institute of Hydrology, Wallingford, England.
Water Resources Research, Vol. 14, No. 1, p 55-61, February, 1978.  8 tab, 11 ref.

Descriptors:  *Streamflow, *Model studies, *Mathematical models, *Monte Carlo
method, *Synthetic hydrology, *Variance reduction, *Hydrological extremes,
Regression analysis, Estimating, Probability.

An estimate F of a water resource system's performance, when it is derived by
simulation using synthetic sequences, is subject to at least three errors; first,
model errors, arising from the approximation to the "true" streamflow mechanism
which the model represents; second, sampling errors in the model parameters theta
when they are calculated from the historic records; and third, errors introduced
by the Monte Carlo calculation from which F is derived.  This paper presented
some observations on the effects of the first two types of error on the estimate
F but concentrated on the application of variance reduction techniques to the
derivation of Monte Carlo estimates F for given theta.  These techniques were,
first, the use of control variates, and second, the use of antithetic variates.
The application of the technique was illustrated by using some hypothetical
examples of the calculation of probabilities of extreme hydrological events and
of the calculation of reliability measures for a much oversimplified storage sy-
stem.  Considerable reduction in the variance of F resulted from the application
of the control variate method; the reduction in Var F resulting from the use of
antithetic variates was much less but still probably worth the small additional
programming effort required.  It was concluded that the promise of the control
variate method suggests that it should be applied to assist in the efficient
simulation of more realistic water resource systems than the trivial ones
considered in this paper.


78:02E-002
A UNIFYING SET OF PROBABILITY TRANSFORMS FOR STOCHASTIC HYDROLOGY,
Snyder, W.M., Mills, W.C., and Knisel, W.G.,  Jr.
Agriculture Research Service, Athens, Georgia, Southeast Watershed Laboratory.
Water Resources Bulletin, Vol. 14, No. 1, p 83-98, February, 1978.  9 fig, 3 tab,
6 ref.

Descriptors:  *Synthetic hydrology, *Statistics, *Probability, Model studies,
Storms, Floods, Design storm, Statistical methods. Stochastic processes,
Lognormal distributions.

An ordered set of probability density functions was derived from transforms of
the normal distribution.  Variate transforms were based on orders of exponentia-
tion.  The set of distributions included the log-normal.  A partial basis for
use of these functions in hydrology was demonstrated by establishing some
required properties.  A concept of mixed samples of zero and nonzero elements
forming nonseparable sets of virtual and real elements was introduced to esta-
blish a physical lower limit of samples data independent of functional bounds.


78:02E-003
RIVER TRANSPORT MODELING FOR UNSTEADY FLOWS,
Reefer, T.N., and Jobson, H.E.
Sutron Corporation, Arlington, Virginia.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol.
104, No.  HY5, Proceedings Paper 13735, p 635-647, May, 1978.  4 fig, 1 tab,
9 ref, 2 append.

                                       12

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Descriptors:  *Streamflow, *Unsteady flow, *Mass transfer, *Georgia,
*Chattahoochee River (Georgia), Model studies, Dye releases, River flow,
Dispensing, Hydraulics.

Coupled flow-mass transport models were applied to a 17-mile (27.8-km) reach
of the Chattahoochee River between Buford and Norcross, Georgia.  Discharge
variations from 550 cfs to 8,000 cfs (15 cu m/s to 100 cu m/s)  in less than 20
min were analyzed.  Accompanying stage variations were as much as 7 ft (2 m).
Two data sets with 5-min time resolution were used to calibrate and verify the
flow model.  A longitudinal depth profile at steady low flow also was used in
the calibration.  Data from a 3-day continuous-injection dye study were used to
verify the mass-transport model.  The study demonstrated the feasibility of
coupled models under highly unsteady flow conditions.  The dye study demonstrated
the unusual nature of conservative mass transport in unsteady flow.  Both the
flow and mass-transport models produced answers approaching the accuracy of the
data.  These are estimated as + or - 29 min in time, + or - 15%-20% for discharge,
and + or - 0.5-ft (0.1-m) for stage.


78:02E-004
PRESERVATION OP THE RESCALED ADJUSTED RANGE 3.  FRACTIONAL GAUSSIAN NOISE
ALGORITHMS,
Hipel, K.W., and McLeod, A.I.
Waterloo University, Ontario, Department of Systems Design.
Water Resources Research, Vol. 14, No.  3, p 517-518, June, 1978.  14 ref.

Descriptors:  *Computer models, *Mathematical models, *Hydrology, *Fractional
Gaussian noise algorithms, *Rescaled adjusted range, Hurst coefficient,
Time series analysis, Stochastic processes, Streamflow, Model studies.

Improved modeling procedures are available for use with a discrete time fractional
Gaussian noise (FGN) model.  These advancements in FGN modeling consist of an
exact simulation procedure, a maximum likelihood approach to obtain efficient
stimates of the model parameters, and a technique for calculating the model
residuals so that they can be subjected to rigorous diagnostic checks.  The
computer algorithms for the aforementioned modeling improvements are available
on microfiche.  The intention of this article was 'to summarize the essential
ingredients of the complete paper, which appears on microfiche.


78;02E-005
STREAM TEMPERATURE ESTIMATION USING KALMAN FILTER,
Chiu, C-L., and Isu, E.G.
Pittsburgh University, Pennsylvania, Department of Civil Engineering.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY9, p 1257-1268, September, 1978.   4 fig, 16 ref, 33 equ,  2 append.

Descriptors:  Water temperature, Streams, Mathematical models,  Streamflow,
Estimating, Forecasting, Stochastic processes.

The technique presented in this paper for estimating the daily Streamflow tempera-
ture uses the Kalman filtering in which an observation and a (mathematical)
system models were combined.  The mathematical system model in turn combined a
deterministic sinusoidal temperature model with a simple, stochastic (first-
order autonegressive) model used to deal with the random deviation, from the
actual temperature, of the temperature estimation given by the sinusoidal model.
In this study the estimation and forecasting technique was tested for its capa-
bility to generate  (predict or estimate) daily Streamflow temperatures between
measurements at several different measurement intervals ranging from 2 days to
15 days.  The estimated temperatures were compared with the observed.  The results
showed several advantages of using Kalman filter over other existing models.


78:02E-006
CLIMATE, SOIL AND VEGETATION 5.  A DERIVED DISTRIBUTION OF STORM SURFACE RUNOFF,
Eagleson, P.s.
Massachusetts Institute of Technology,  Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No.  5, p 741-748, October, 1978.  6 fig, 2 tab,
11 ref, 76 equ.
(See 78:02A-009)

                                       13

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78:02E-007
A FEATURE PREDICTION MODEL IN SYNTHETIC HYDROLOGY BASED ON CONCEPTS OF PATTERN
RECOGNITION,
Panu, U.S., and Unny, T.E.
Waterloo University, Ontario, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 2, p 335-344, April, 1978.  7 fig, 4 tab,
23 ref.

Descriptors:  *Synthetic hydrology, *Hydrologic data, *Modelstudies, *Stochastic
processes, *Feature prediction model, *Saskatchewan River, Pattern recognition,
Time series analysis, Methodology, Hydrology.

It is reasonable to consider that sequences of hydrologic data corresponding to
daily, weekly, or monthly measurements occur in well-defined groups.  These
groups possess collective properties of the data forming them.  Such a cbl-lection
of properties can be called a hydrologic pattern.  A pattern is a description
of an object; and the objects of concern in this paper were groups of data on
hydrologic phenomena observed at regular time intervals.  Hydrologic patterns
describing each of these groups are expressed by n appropriate properties.
Further, the dimensionality, n in number, can be reduced by considering only
those characteristic properties, m in number ( m less than or = to n), that
are common in all hydrologic patterns of the same category.  These m characteris-
tic properties are called features.  A procedure was presented to extract infor-
mation present within patterns and among patterns of the pertinent hydrologic
data.  In addition, on the basis of the above information, a zero-order Markov
feature prediction model was postulated.  The basic assumptions of the model and
their implications were presented.  The model was applied to South Saskatchewan
River flow data in an effort to demonstrate its usefulness in real situations.


78:02E-OQ8
PRESERVATION OF THE RESCALE ADJUSTED RANGE 1.  A REASSESSMENT OF THE HURST
PHENOMENON,
McLeod, A.I., and Hipel, K.W.
University of Western Ontario, London, Department of Mathematics.
Water Resources Research, Vol. 14, No. 3, p 491-508, June, 1978.  8 fig, 10 tab,
67 ref.

Descriptors:  *Model studies, *Mathematical models, *Hydrology, *Rescaled adjusted
range. Stochastic processes, Mathematics, Streamflow, River flow, Time series
analysis. Simulation analysis.

Previous research related to the controversial Hurst phenomenon was reviewed and
evaluated.  Because of the inherent statistical properties of the rescaled ad-
justed range (RAR) statistic, it was suggested that research primarily be devoted
to this statistic rather than to the various definitions of the Hurst coefficient.
Simulation studies revealed that for independently distributed random variables
the RAR does not depend significantly on the underlying distribution of the ran-
dom variables but is a function of the sample size.  For modeling correlated
data,, the statistical attributes of a discrete fractional Gaussian noise (FGN)
process were studied and also improved.  An efficient maximum likelihood estima-
tion technique was developed for the FGN model, and it was shown how the resi-
duals of the fitted model can be calculated and then subjected to diagnostic
checks.  An exact simulation procedure was developed for simulating FGN in such
a way that, synthetic traces from the model lie outside the Brownian domain.  The
Akaike information criterion (AIC) was suggested as a method for choosing bet-
ween a FGN and a Box-Jenkins model.  For the six annual river flow series that
were considered, the AIC selected the best Box-Jenkins model in preference to
the FGN process for each data set.  Because Box-Jenkins models can be shown to
preserve the historical RAR, in many practical applications it may be advantageous
to use a Box-Jenkins model instead of a FGN process.


78:02E-009
PRESERVATION OF THE RESCALED ADJUSTED RANGE 2.   SIMULATED STUDIES USING BOX-
JENKINS MODELS,
Hipel, K.W., and McLeod, A.I.
Waterloo University, Ontario, Department of Systems Design.
Water Resources Research, Vol. 14, No. 3, p 509-516, June, 1978. . 6 tab, 34 ref.


                                       14

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Descriptors:  *Model studies, *Mathematical models, *Hydrology, *Box-Jenkins
models, *Rescaled adjusted range, Stochastic processes, Mathematical studies,
Monte Carlo method, Time series analysis, Geophysics.

It was demonstrated that autoregressive moving average (Arma)  models do preserve
the rescaled adjusted range  (RAR), or equivalently the Hurst coefficient K.
Arma models were fitted to 23 geophysical time series, and by using Monte Carlo
techniques and a specified statistical test it was' shown that the observed RAR
or K is retained by the models.  The empirical cumulative distribution function
(ECDF) for these statistics can be calculated as closely as is required to the
theoretical distribution.  Furthermore, the distribution of the RAR is a function
of the time series length N and the parameter values of the particular Arma
process being considered.  Various estimates for the Hurst coefficient were com-
pared for the 23 geophysical data sets.


78:02E-010
DISCHARGE-DEPTH EQUATION FOR SHALLOW FLOW,
Turner, A.K., Langford, K.J., Win, M., and Clift, T.R.
Melbourne University, Parkville, Australia, Department of Civil Engineering.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 104, No. IR1, Proceedings Paper 13626, p 95-110, March, 1978.
9 fig, 3 tab, 20 ref, 2 append.

Descriptors:  *Flow, *0verland flow, *Roughness (hydraulic), *Model studies,
Vegetation, Crops, Soils, Sheet flow, Retardance, Surface runoff, Equations.

The application of a discharge-depth equation  (with variable coefficient and
exponent) was recommended for shallow flows of water over soil and through
vegetation.  The more flexible nature of this equation over the commonly used
channel flow equations was considered, and typical values were given for three
conditions, viz, bare uneven soil, artificial vegetation, and pasture and crop
covers growing on a sandy soil.


78:02E-011
RESIDUE AND TILLAGE EFFECTS ON SCS RUNOFF CURVE NUMBERS,
Rawls, W.J., and Onstad, C.A.
Hydrology Laboratory, Science and Education Administration, Agricultural
Research, Beltsville, Maryland, United States Department of Agriculture.
Paper No. 78-2505, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 18 p.  5 fig, 7 tab, 22 ref.

Descriptors:  Runoff, Surface runoff, Soil conservation, Till, Rainfall,
Simulated rainfall, Estimating, Small watersheds. Corn  (field), Grains  (crops).

Data  from 525 simulated and  natural rainfall events were used to develop guides
for estimating the effect of conservation tillage practices on the SCS runoff
curve numbers for corn and small grain.  The amount of residue on the ground or
the percent of surface covered with residue was used to represent the effect
of conservation tillage practices.
                                        15

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                                SECTION VI

                                WATER CYCLE

                          GROUNDWATER  (GROUP 02F)
78:02F-001
POROUS MEDIA TESTS OF GROUNDWATER MOUNDS,
Mousavi, S.-F., Kirkham, D.
Iowa State University, Ames, Department of Agronomy.
Soil Science Society of America Journal, Vol. 125, No. 3, p 160-164, March,
1978.  8 fig, 14 ref.

Descriptors:  *Model studies, *Porous media, *Groundwater recharge, Pit recharge,
Equations, Testing, Laboratory tests, Hydraulic conductivity, Infiltration,
Groundwater mounds.

To test the theoretical equations for the shapes of groundwater mounds formed
under rectangular and circular recharge basins, two Plexiglas laboratory models
were constructed.  Glass beads, white silica sand, and gravel were used as porous
media, and a 60% glycerol-water mixture was used as the recharge fluid.  The
mound heights, measured at various distances from the centers of the mounds, were
compared with the theoretical mound heights.  The experimental mound heights
showed good agreement with theoretical ones, both for the two-dimensional and
the three-dimensional axial symmetric mounds.


78:02F-002
EFFECTS OF CORN STOVER, MANURE, AND NITROGEN ON SOIL PROPERTIES AND CROP YIELD,
Ketcheson, J.W., and Beauchamp, E.G.
Guelph University, Canada, Department of Land Resource Science.
Agronomy Journal, Vol. 70, No. 5, p 792-797, September^October, 1978.  4 fig,
8 tab, 6 ref.

Descriptors:  Nitrogen, Fertilizers, Corn (field), Organic matter, Farm wastes,
Soil properties, Crop response, Soil treatment.

Residues and farmyard manures are considered important in determining the N
fertilizer requirement of crops.  This relationship was studied in a 10-year
field experiment on a Typic Hapludalf soil  (pH 7.8).  Five levels of fertilizer
N were applied annually with three management treatments which included 1) return-
ing the stover produced by the preceding corn (Zea mays L.) crop, 2) poultry
manure equivalent to 112 kg N/ha/year and 3) no stover returned or manure applied.
Dry matter yields and N in grain and stover were measured each year.  In general,
the manure treatment without N fertilizer gave yields comparable with any other
treatment.  Where fertilizer N was applied, stover resulted in slightly higher
yields than where stover was removed.  Stover returned to the soil did not in-
crease fertilizer N requirements at normal rates of application.  It was con-
cluded that corn stover residue did not affect the N fertilizer requirement of
this soil for grain corn production.  Annual applications of liquid poultry
manure, containing N equivalent to 112 kg/ha, precluded a requirement for ferti-
lizer N.


78:02F-003
AN APPROXIMATE DIFFERENTIAL EQUATION TO DESCRIBE LEAKY AQUIFER BEHAVIOR DURING
INTERMEDIATE AND LARGE VALUES OF TIME,
Rodarte, L.
Universidad Nacional Autonoma de Mexico, Mexico City, Department of Ingeniera.
Water Resources Research, Vol. 14, No. 1, p 39-44, February, 1978.  6 fig, 12 ref.
                                      16

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Descriptors:  *Aquifers, *Groundwater,  *Model studies, ~*Leaky aquifers. Mathe-
matical models. Equations, Leakage, Flow, Pumping, Drawdown.

In analyzing a leaky aquifer for application in regional studies, it is of great
interest to have available simplified mathematical representations from which an
analogical or digital model of the problem can be constructed.  In this paper, a
differential equation valid for intermediate and large values of time was pro-
posed.  Also, an analytical solution corresponding to an isolated well as a test
of the range of applicability of the proposed equation was obtained.


78:02F-004
THEORY AND NUMERICAL ANALYSIS OP MOVING BOUNDARY PROBLEMS IN THE HYDRODYNAMICS
OF POROUS MEDIA,
Nakano, Y.
Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire.
Water Resources Research, Vol. 14, No.  1, p 125-134, February, 1978.  4 fig, 5
tab', 14 ref.

Descriptors:  *Mathematical studies, *Theoretical analysis, *Numerical analysis,
*Boundaries  (surfaces), *Porous media,  Equations, Groundwater movement, Moving
boundaries.

The exact mathematical description of a boundary between unsaturated flow and
saturated flow as well as a wetting front were obtained.  A new concept for
numerical analysis of flow in partly unsaturated and partly saturated porous
medium was introduced.  A boundary of infinitesimal width intersecting the unsat-
urated and saturated parts was substituted by an artificial transitional zone of
finite width for computational simplicity.  The concept was proved to be theo-
retically justificable.  The feasibility of the concept was demonstrated as it
was applied to a two-dimensional finite difference solution of a special problem
of column drainage, for which an analytical solution was obtained.


78:02F-005
LAS VEGAS VALLEY WATER BUDGET:  RELATIONSHIP OF DISTRIBUTION, CONSUMPTIVE USE,
AND RECHARGE TO SHALLOW GROUNDWATER,
Patt, R.O.
Desert Research Institute, Las Vegas, Nevada  89109.
Publication No. EPA-600/2-78-159, July, 1978.  61 p, 16 fig,  8 tab, 19 ref, 3
append.

Descriptors:  Groundwater, Groundwater recharge, Water' consumption.

Estimates of quantity and geographic distribution of recharge to the shallow
groundwater  zone from water use return flows in Las Vegas Valley were made for
the years 1973, 1965, 1958, 1950, and 1943 as part of  a broader study on the
impact of water and land use on groundwater quality.   Considered components of
water use in Las Vegas Valley include the following:   supply  from surface and
groundwater; agriculture using potable water; agriculture using sewage effluent;
residential  lawn watering; lawn watering of parks, schools, cemetaries, hotels,
motels; golf courses using potable water; golf courses using  sewage effluent
water; septic tank recharge; evaporative coolers; system losses' industrial use;
power plant  cooling; swimming pool use; consumptive use by phreatophytes; in-
valley recharge from precipitation, and  "unaccounted for water".  Consumptive
use of plants was calculated through use of the Blaney-Criddle method as 3.47
feet per year and recharge was assumed to be the difference between applied
water and calculated consumptive use.  Data developed  during  this study indi-
cates consumptive use as determined by this method could be low by  1.5 to 2 feet
per year, and thus the following estimates of recharge to the groundwater system
are considered maximum, in acre feet:  1973-39,000; 1965-27,600; 1958-26,650;
1950-13,000; and 1943-21,000.


78:02F-006
NUMERICAL MODEL FOR SATURATED-UNSATURATED FLOW IN DEFORMABLE  POROUS MEDIA.
2.  THE ALGORITHM,
Narasimhan,  T.N., Witherspoon, P.A., and Edwards, A.L.
California  University, Berkeley, Lawrence Berkeley Laboratory.
Water  Resources Research, Vol. 14, No. 2, p 255-261, April, 1978.   3 fig, 8 ref.

                                     17

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 Descriptors:   *Numerical analysis,  *Mathematical models,  *Porous media,  *Satur-
 ated flow,  *Unsaturated flow,  *Algorithms,  *Integrated-finite-difference method,
 Equations,  Groundwater movement,  Aquifer characteristics.

 An integrated finite  difference  algorithm was presented for numerically  solving
 the governing equation of saturated-unsaturated flow in deformable porous media.
 In recognition that stability  of  the explicit equation is  a local phenomenon,  a
 mixed explicit-implicit procedure was used  for marching in the time domain.   In
 this scheme,  the  explicit changes in potential are first  computed for all ele-
 ments in  the  system,  after which  implicit corrections are  made only for  those
 elements  for  which the stable  time  step  is  less than the  time step being used.
 Time step sizes are controlled automatically  in order to optimize the number of
 iterations, to control maximum change in potential during  a time step, and to
 obtain desired outputs.   Time  derivatives,  estimated on the basis of system
 behavior  during two previous time steps,  are  used to start the iteration -process
 and to evaluate nonlinear coefficients.   Boundary conditions and sources can
 vary with time or with the dependent variable.   Input data are organized into
 convenient  blocks.  Accuracy of  solutions can be affected  by modeling errors,
 different types of truncation  errors,  and convergence errors.   The algorithm
 constitutes an efficient tool  for analyzing linear and nonlinear fluid flow
 problems  in multidimensional heterogeneous  porous media with complex geometry.
 An important  limitation  is that the  model cannot conveniently handle arbitrary
 anisotropy  and other  general tensorial quantities.


 78:02F-007
 STOCHASTIC ANALYSIS OF SPATIAL VARIABILITY  IN SUBSURFACE FLOWS.   1.   COMPARISON
 OF ONE- AND THREE-DIMENSIONAL  FLOWS,
 Bakr,  A.A., Gelhar, L.W.,  Gutjahr, A.L.,  and  MacMillan, J.R.
 New Mexico  Institute  of  Mining and Technology,  Socorro.
 Water  Resources Research,  Vol. 14, No. 2, p 263-271,  April,  1978.   4 fig,  23 ref.

 Descriptors:   *Stochastic  processes,  *Hydraulic conductivity,  *Subsurface  flow,
 *Aquifers, Groundwater movement,  Statistical  models,  Equations,  Hydraulic  grad-
 ient,  Mathematical models, Monte  Carlo method.

 The  complex variation  of hydraulic conductivity in  natural  aquifer materials is
 represented in a  continuum sense  as  a  spatial  stochastic process which is  char-
 acterized by  a covariance  function.   Assuming  statistical homogeneity, the theory
 of  spectral analysis was used  to  solve perturbed forms  of the  stochastic differ-
 ential equation describing flow through porous  media  with randomly varying hy-
 draulic conductivity.   From analyses of unidirectional  mean  flows which  are
 perturbed by  one- and  three-dimensional variations  of the logarithm  of the hy-
 draulic conductivity,   local relationships between  the head  variance  and  the log
 conductivity  variance  were obtained.   The results  showed that  the head variance
 produced by three-dimensional  statistical isotropic conductivity perturbations  is
 only 5% of that in the corresponding one-dimensional  case.   The head variance  is
 also strongly dependent  on the correlation  distance of  the  log conductivity
 covariance function.    These results  emphasized  the  importance of including
 spatial correlation structure  and multidimensional  effects  in  stochastic simula-
 tion of groundwater flow.
                     * •

 78:02F-008
AN EFFICIENT NUMERICAL METHOD OF TWO-DIMENSIONAL STEADY GROUNDWATER  PROBLEMS,
Liu, P.L.-F.,  and Liggett, J.A.
Cornell University,  Ithaca, New York,  School of Civil and Environmental Engineer-
 ing.
Water Resources Research, Vol.  14, No. 3, p 385-390,  June,  1978.  6  fig,  2 tab,
 11 ref.

Descriptors:  *Groundwater movement, *Groundwater,  *Model studies, Mathematical
models, Seepage, Dams, Earth dams, Saline water intrusion, Saline water-freshwater
interfaces, Aquifers.

The boundary integral  equation method  (BIEM) was shown to be an efficient and
accurate numerical technique for solving problems of Darcy flow in porous media.
The BIEM was combined  with conformal transformation to the complex potential plane
to solve free  surface  problems without iteration and with relatively few nodal



                                      18

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points.  Since the BIEM reduces the effective dimensions of the problem by one,
the computer time varies approximately as the inverse square of the point spacing;
whereas in finite element or finite difference methods; the time varies approxi-
mately as the inverse of the 4th power of the point spacing.  Two examples of the
BIEM were presented:  flow through an underdrained dam, and a seawater intrusion
problem.


78:02F-009
THEORY OF FLOW IN UNCONFINED AQUIFERS BY INTEGRODIFFERENTIAL EQUATIONS,
Herrera, I., Minzoni, A., and Flores, E.2.
Universidad Nacional Autonoma de Mexico, Mexico City, Centre de Investigaciones
en Matematicas Aplicadas y en Sistemas.
Water Resources Research, Vol. 14, No. 2, p 291-297, April, 1978.  3 fig, 1 tab,
18 ref, 1 append.

Descriptors:  *Aguifers, *Drawdown, *Theoretical analysis, *Mathematical models,
Groundwater movement, Unsteady flow, Groundwater, Flow, Compressible flow.
Porous media.

It was shown that when the diffusion of the deviation of the drawdown from its
average value can be neglected, the unsteady flow in unconfined aquifers is
governed by an integrodifferential equation.  For incompressible flow, this
equation reduces the Boulton's delayed yield equation with epsilon = 3.  When
the flow is compressible, the kernel can be approximated by Boulton's delayed
factor in a range of times whose lower limit approaches zero with the compress-
ibility.


78:02F-010
STEADY PHREATIC FLOW OVER A SLOPING SEMIPERVIOUS LAYER,
Mualem, Y., and Bear, J.
Colorado State University, Fort Collins, Engineering Research Center.
Water Resources Research, Vol. 14, No. 3, p 403-408, June, 1978.  7 fig, 10 ref.

Descriptors:  *Groundwater movement, *Groundwater,- *Model studies, Mathematical
models, Boundary layers, Impervious soils, Flow, Steady flow, Slopes, Equations.

This work dealt with steady phreatic flow above a thin semipervious sloping layer
located at some distance below ground surface and above the water table of an
underlying phreatic aquifer.  Cases of both upsloping and downsloping semiper-
vious layers were studied.  A uniform recharge of constant rate and a semiper-
vious layer of finite length were considered, either with length of flow shorter
than the semipervious layer with flow bypassing its edge.  For each case, linear-
ization was applied to the nonlinear continuity equation which governs the flow.
Analytical solutions were derived then for the shape of the phreatic flow wedge,
the length of the wedge, and the discharge rate.  These results were compared
with experimental ones obtained in a Hele-Shaw analog.. A good agreement gener-
ally was found between computed and observed results.  Because of the analogy
which exists between a phreatic surface and an interface in a coastal aquifer,
the same results also can be applied to the steady freshwater flow above an
interface in an aquifer divided into two subaquifers by a sloping semipervious
layer.

78:02F-011
SENSITIVITY OF OPTIMIZED PARAMETERS IN WATERSHED MODELS,
Mein, R.G., and Brown, B.M.
Monash University, Clayton, Australia, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 2, p 299-303, April, 1978.  1 fig, 2 tab,
12 ref.

Descriptors:  *Model studies, *Watersheds (basins), *Simulation analysis, *Meth-
odology, *Hydrologic data, *Boughton model, Analytical techniques, Statistics,
Optimization, Forecasting.

Models which attempt to simulate specifically each of the important hydrologic
components of the watershed response appear to have more potential than black box
models for predicting the effect of. land use change, for application to ungaged
watersheds, and for general studies of the effects of each process on watershed


                                      19

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runoff.  It has been common practice to evaluate some or all parameters of
watershed models by fitting procedures.  A methodology was presented by which
the variance of each fitted parameter of a watershed model can be determined.
This information can be used to determine the degree to which the model para-
meters can be related to physical characteristics.  The method was illustrated
by applying the Boughton model to several watersheds and by examining the coef-
ficient of variation of each optimized parameter.


78:02F-012
UNSTEADY FLOW TO A PUMPED WELL IN A FISSURED AQUIFER WITH A FREE SURFACE LEVEL
MAINTAINED CONSTANT,
Boulton, N.S., and Streltsova, T.D.
Sheffield University, England, Department of Civil and Structural Engineering.
Water Resources Research, Vol. 14, No. 3, p 527-532, June, 1978.  6 fig, 2 tab,
6 ref.

Descriptors:  *Aquifers, *Puraping, *Drawdown, *Model studies, Mathematical
models, Groundwater, Groundwater movement. Flow, Fissures  (geologic), Water
levels, Equations.

New equations were derived for the drawdown in an aquifer consisting of two hori-
zontal layers referred to as the block and the fissure, which have different
hydraulic properties.  The free water surface forming the upper aquifer boundary
was located in the block.  The water level was assumed to remain constant during
pumping.  The block and the fissure were compressible.  The depth of the fissure
was small in comparison with that of the block.  The abstraction well, lined
along the block, was'pumped at a constant rate.  The discharge per unit length
of the unlined part in the fissure was constant, and the radius of the well was
vanishingly small.  Type curves for the drawdown in the fissure and the block
were computed and plotted for some selected parameters involved.  The effect of
the block compressibility on the drawdown in the fissure was shown by comparing
the type curves with the type A drawdown curves of Boulton.  The influence of the
free surface compared with that of an impervious top layer on the drawdown in the
fissure and the block was estimated by comparing the type curves with those of
Boulton and Streltsova found from the equations for a two-layered formation, the
top and bottom surfaces of which were impermeable.


78:02F-013
ANALYSIS OF DYNAMIC AQUIFERS WITH STOCHASTIC FORCING FUNCTION,
Sagar, B.
Department of the Environment, Ottawa, Ontario, Hydrology Research Division; and
Department of the Environment, Ottawa, Ontario, Inland Waters Directorate.
Water Resources Research, Vol. 14, No. 2, p 207-216, April, 1978.  6 fig, 28 ref.

Descriptors:  *Saturated flow, *Aquifers, *Mathematical models, *Stochastic pro-
cesses, Model studies, Mathematical studies, Analytical techniques, Analysis,
Flow, Porous media.

The existence of different types of uncertainties in deterministic aquifer
models and the need "of quantitatively accounting for them were discussed.  The
case of one-dimensional saturated flow represented by a linear parabolic partial
differential equation with a stochastic forcing function was analyzed.  The
dependence of the autocovariance function of the hydraulic head on properties of
the forcing function and nature of the aquifer was brought out.


78:02F-014
A FINITE ELEMENT STUDY OF STEADY STATE FLOW IN AN UNCONFINED AQUIFER RESTING ON
A SLOPING BED,
Choi, E.C.C.
Hong Kong University, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 3, p 391-394, June, 1978.  5 fig, 3 tab,
12 ref.

Descriptors:  *Aquifers, *Groundwater movement, *Model studies, Mathematical
models, Finite element analysis, Beds, Boundary layers, Impervious soils, Ground-
water, Seepage, Flow, Slopes, Hydrology, Impermeable beds.


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A two-dimensional finite element method was used to study the problem of seepage
over a sloping impermeable bed.  Flow profile and seepage rates obtained from
the analysis were compared with those solved from Pavlovsky's and Childs1 equa-
tions.  The latter equation was found to be more favorable, especially for large
slopes.  The effects on the flow profile due to a change in the upstream and
downstream conditions and to a sudden change in the magnitude of the slope to
the impermeable bed also were investigated.


78:02F-015
NUMERICAL SIMULATION OF STEADY STATE THREE-DIMENSIONAL GROUNDWATER FLOW NEAR
LAKES,
Winter, T.C.
Geological Survey, Denver, Colorado, Water Resources Division.
Water Resources Research, Vol. 14, No. 2, p 245-254, April, 1978.  14 fig, 8 ref.

Descriptors:  *Groundwater movement, *Lakes, *Seepage, *Surface-groundwater re-
lationships, *Three-dimensional simulation analysis, *Lake-water budget, Model
studies. Numerical analysis, Simulation analysis, Hydrogeology.

Numerical simulation of three-dimensional groundwater flow near lakes shows that
the continuity of the boundary encompassing the local groundwater flow system
associated with a lake is the key to understanding the interaction of a lake with
the groundwater system.  The continuity of the boundary can be determined by the
presence of a stagnation zone coinciding with the size of the lake nearest the
downgradient side of the groundwater system.  For most settings modeled in this
study the stagnation zone underlies the lakeshore, and it generally follows its
curvature.  The length of the stagnation zone is controlled by the geometry of
the lake's drainage basin divide on the side of the lake nearest the downgradient
side of the groundwater system.  In the case of lakes that lose water to the
groundwater system, three-dimensional modeling also allows for estimating the
area of lake bed through which outseepage takes place.  Analysis of the effects
of size and lateral and vertical distribution of aquifers within the groundwater
system on the outseepage from lakes shows that the position of the center point
of the aquifer relative to the littoral zone on the side of the lake nearest the
downgradient side of the groundwater system is a critical factor.  If the center
point is downslope from this part of the littoral zone, the local flow system
boundary tends to be weak or outseepage occurs.  If the center point is upslope
from this littoral zone, the stagnation zone tends to be stronger (to have a
higher head in relation to lake level), and outseepage is unlikely to occur.


78:02F-016
NON-STEADY SPHERICAL FLOW TO A CAVITY WELL IN AN INFINITE NONr-LEAKY AQUIFER,
Kanwar, R.S., and Chauhan, H.S.
Iowa State University, Ames, Department of Agricultural Engineering.
Water Resources Bulletin, Vol. 14, No. 3, p 605-612, June, 1978.  1 fig, 10 ref.

Descriptors:  *Groundwater, *Groundwater movement, *Water wells, *Model studies,
Mathematical models, Equations, Aquifers, Wells, Drawdown, Hydraulic conductivity.

The non-steady drawdown distribution near a cavity well discharging from an in-
finite non-leaky artesian aquifer was presented.  The variation of drawdown with
time and distance caused by a cavity well of constant discharge in a confined
aquifer of uniform thickness and uniform permeability was obtained.   The solution
was expressed in a series form which converged rapidly so that only two terms of
the series are needed to obtain an accuracy of more than 95%.  A simplified
approach was suggested to find the aquifer characteristics.


78:02F-017
A NOTE ON PACKER, SLUG, AND RECOVERY TESTS IN UNCONFINED AQUIFERS,
Dagan, G.
Tel Aviv University, Ramat-Aviv, Israel, School of Engineering.
Water Resources Research, Vol. 14, No. 5, p 929-934, October, 1978.   3 fig, 1 tab,
4 ref, 45 equ.

Descriptors:  Water table aquifers, Hydraulic conductivity, Permeability, Well
data, Steady flow, Numerical analysis.


                                      21

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Packer, slug, and recovery tests are common procedures for determining the
hydraulic conductivity of unconfined formations of low permeability.  The vol-
umes of water injected or removed from the -borehole are small, so that the water
table remains horizontal and the flow is steady.  The flow problem is solved by
source distributions along the well axis.  A simple numerical method and numer-
ical results covering a wide range of the parameters of the problem were pre-
sented.  The main limitation of the method is the requirement that the active
portion of the well length should be much larger  (say, 50 times) than the well
radius.


78:02F-018
STEADY-STATE DRAWDOWNS IN COUPLED AQUIFERS,
Motz, L.H.
Geraghty and Miller, Inc., Tampa, Florida.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol.
104, No. HY7, Proceedings Paper 13886, p 1061-1074, July,1978.  8 fig, 1 tab,
14 ref.

Descriptors:  *Aquifers, *Leakage, *Drawdown, *Mathematical models, Equations,
Groundwater movement, Pumping, Steady flow, Evapotranspiration, Water resources.

The analytical linear solution that predicts the steady-state drawdowns for a
coupled two-aquifer system in which pumping from an underlying artesian aquifer
is balanced by a reduction in evapotranspiration from an overlying water-table
aquifer was developed.  An example illustrating how the drawdown equations can
be used to determine whether significant drawdowns will occur in the water-table
aquifer was presented.  These drawdown equations can be used for preliminary
analysis and planning studies and to test the convergence of digital model solu-
tions when these more sophisticated techniques are warranted.  A major limitation
to using these equations is that the predicted water table drawdowns cannot be
so great that evapotranspiration would cease altogether and, thus, could not be
reduced any further to balance the pumping.


78:02F-019
SOLUTIONS OF BOUSSINESQ'S EQUATION FOR SEEPAGE FLOW,
Gureghian, A.B.
Argonne National Laboratory, Illinois, Division of Environmental Impact Studies.
Water Resources Research, Vol. 14, No. 2, p 231-236, April, 1978.  6 fig, 2 tab,
19 ref.

Descriptors:  *Seepage, *Equations, *Groundwater, *Boussinesq's equation, Seepage
control, Ditches, Finite element analysis, Hydrology, Soils, Channels.

Solutions of Boussinesq's equation for groundwater seepage from a ditch with
vertical sides extending in depth to a horizontal impermeable floor were obtained
numerically by using the finite difference and finite element methods for the
case when the seepage rate from the ditch into the soil is constant with time.
Both solutions agreed satisfactorily with experimental results from a Hele-Shaw
analog.  It was found, however, that the execution time in the computer for the
finite difference method was an order shorter than that for the finite element
method, and thus the finite difference method is to be preferred.  The finite
difference method also was used to obtain a numerical solution for the reverse
situation when water seeps out of the soil into the ditch at a constant rate.


78:02F-020
GROWTH OF GROUNDWATER MOUNDS AFFECTED BY IN-TRANSIT WATER,
Ortiz, N.V., McWhorter, D.B., Sunada, O.K., and Duke, H.R.
Colorado State University, Fort Collins, Engineering Research Center..
Water Resources Research, Vol. 14, No. 6, p 1984-1088, December, 1978.  8 fig,
13 ref..

Descriptors:  Groundwater, Water table, Aquifers, Storage capacity, Analytical
techniques, Numerical analysis, Porous media, Water table, Aquifers.
                                     22

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An analytical solution accounting for the reduction in storage capacity caused
by intransit water was presented for the growth of groundwater mounds in an un-
confined aquifer in response to uniform deep percolation from a strip of infinite
length but finite width.  The solution was obtained by integrating the solution
for the analogous case of heat flow in a composite solid with respect to time.
The aquifer-was considered to be homogeneous, isotropic, and infinite in areal
extent and rested on a horizontal impermeable base.  The results from the ana-
lytical solution were compared with those obtained from a numerical model which
was previously verified with data obtained from a physical porous media model.
Dimensionless curves were presented to afford a relatively simple means of ana-
lyzing the growth of groundwater mounds.


78:02F-021
ON THE DETECTION OF SHALLOW AQUIFERS USING THERMAL INFRARED IMAGERY,
Huntley, D.
Connecticut University, Storrs, Department of Geology and Geophysics.
Water Resources Research, Vol. 14, No. 6, p 1075-1083, December, 1978.  11 fig,
21 ref.

Descriptors:  Aquifers, Groundwater, Shallow water, Depth, Remote sensing,
Infrared radiation, Radiation, Temperature, Diurnal, Geophysics.

The existence of a tool  (the thermal infrared scanner) that primarily records the
spatial variation in surface temperature, combined with a consideration of the
effect of an aquifer on subsurface heat flow patterns, has led several investi-
gators of remote sensing capabilities to look for relations between the distribu-
tion of aquifers and radiometric temperatures.  Because of the obvious potential
significance of the ability to detect aquifers remotely, this author investigated
the theoretical and practical basis for aquifer detection.  The purpose of this
research was  (1) to determine the effect of varying aquifer depth on diurnal  sur-
face temperature,  (2) to compare the effects produced by varying aquifer depth to
those of varying soil type and soil moisture, and  (3) to determine the optimum
interpretive techniques for location of shallow aquifers using thermal infrared
imagery.  The results of this investigation led to the following conclusions:
(1) with present technology, it is not practical to estimate groundwater depth
directly using thermal infrared imagery,  (2) correlations between groundwater
depth and radiometric temperature noted in the literature are likely caused by
increased evaporative cooling related to increased soil moisture,  (3) estimation
of evaporation from thermal infrared imagery acquired during both day and night
may be feasible.


78:02F-022
AN ITERATIVE QUASI-THREE-DIMENSIONAL FINITE ELEMENT MODEL FOR HETEROGENEOUS
MULTIAQUIFER SYSTEMS,
Chorley, D.W., and Frind, E.O.
Waterloo University, Ontario, Canada N2L 3G1.
Water Resources Research, Vol. 14, No.  5, p  943-952, October,' 1978.  11 fig,  2
tab, 27 ref, 25 equ, 1 append.

Descriptors:  Groundwater movement, Finite element analysis, Aquifer systems,
Aquitards, Model studies. Mathematical models, Analytical techniques, Economic
justification.

A quasi-three-dimensional flow model was developed for the analysis of hydro-
geologic systems consisting of several  aquifers interconnected by aquitards.
Provided only that each  layer was  continuous within the domain and  that a perme-
ability contrast of two  orders of magnitude  or more existed between adjoining
layers, a system could be completely heterogeneous.  Any of the aquifers could be
pumped, and discharge rates could be arbitrary.  Flexibility was iterative, solv-
ing aquifers and aquitards separately and providing coupling through the leakage
flux.  Aquitard storage  and interaction between aquifers were rigorously accounted
for at all times.  Convergence was  demonstrated experimentally by  comparison  with
the analytical  solution  of Neuman  and Witherspoon  (Publ. 69-1, Dept. of Civil
Eng., Univ. of Calif.,  Berkeley,  1969).  The multiaquifer model was shown to  be
much more economical than an equivalent three-dimensional model.
                                      23

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78:02F-023
STOCHASTIC ANALYSIS OF SPATIAL VARIABILITY IN SUBSURFACE FLOWS   2.  EVALUATION
AND APPLICATION,
Gutjahr, A.L., Gelhar, L.W., Bakr, A.A., and MacMillan, J.R.
New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801.
Water Resources Research, Vol. 14, No. 5, p 953-959, October, 1978.  5 fig, 9
ref, 52 equ.

Descriptors:  Subsurface flow, Groundwater movement, Stochastic processes,
Spatial distribution, Porous media, Approximation method, Hydraulic conductivity,
Network design, Aquitards.

The stochastic differential equation describing one-dimensional flow in a sta-
tistically homogeneous porous medium was solved exactly, and the results were
compared with an approximate solution considering small perturbations in the
logarithm of the hydraulic conductivity.  The results showed that the logarithmic
approximation is valid when the standard deviation of the natural logarithm of
the hydraulic conductivity, sigma sub f, is less than 1; the errors increase
rapidly for sigma sub f > 1.  The effective hydraulic conductivity of statis-
tically homogeneous media with one-, two- and three-dimensional perturbations was
determined to the first order in the square of sigma sub f  (SSF).  The effective
conductivity was found'to be the harmonic mean for one-dimensional flow, the
geometric mean for two-dimensional flow, and  (1 + SSF/6) times the geometric
mean for three-dimensional flow.  The application of stochastic analysis was
illustrated through two elementary network design problems that demonstrate the
importance of the correlation length of the hydraulic conductivity and the role
of measurement error.


78:02F-024
THE COMPUTATIONAL EFFICIENCY AND TAYLOR EXPANSION DERIVATION OF APPROXIMATING
EQUATIONS TO THE GROUNDWATER FLOW EQUATION,
Kuiper, L.K.
Ahmadu Bello University, Zaria, Nigeria, Department of Physics.
Water Resources Research, Vol. 14, No. 6, p 1171-1181, December, 1978.  8 fig, 2
tab, 12 ref, 52 equ.

Descriptors:  Groundwater movement. Approximation method, Finite element analysis,
Numerical analysis, Mathematical studies, Groundwater.

In this paper, the relative accuracy and speed of 12 different approximations for
the solution of the homogeneous one-dimensional groundwater flow equation were
compared.  Two of these approximations were derived by the use of finite elements
including both the time and the spacial domain, others by the use of finite ele-
ments in the spacial domain and finite differences in the time domain, and the
remainder by the use of finite differences in both the time and the spacial
domain.  Several generalizations of these approximations for use with the non-
homogeneous one-dimensional groundwater flow equation were also compared for
accuracy.  A general procedure for the derivation of approximations to differen-
tial equations was presented.


78:02F-025
GALERKIN FINITE ELEMENT PROCEDURE FOR ANALYZING FLOW THROUGH RANDOM MEDIA,
Sagar, B.
Punjab Agricultural University, Ludhiana 141004, India, Department of Civil
Engineering.
Water Resources Research, Vol. 14, No. 6, p 1035-1044, December, 1978.  3 fig, 2
tab, 19 ref, 28 equ.

Descriptors:  Groundwater movement, Flow around objects, Porous media/ Stochastic
processes, Finite element analysis, Mathematical studies, Statistical methods.

A method was presented for analyzing flow through a porous medium whose parameters
are random functions.  Such a medium was conceptualized as an ensemble of media
with an associated probability mass function.   The flow problem in each member of
this ensemble is deterministic in the usual sense.  All the solutions belong to a
particular Hilbert space, and hence they can be written in terms of linear com-
binations of its basis functions.  This is similar to the Galerkin formulation


                                      24

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except that the coefficients in the linear combination are no longer deterministic
quantities but random functions.  The finite element method in conjunction with
a Taylor series expansion was used to get the first two moments of the solution
approximately.  The method does not require specification of full probability
mass functions of the parameters but only their first two moments, and spatial
correlations can be easily accounted for.  However, it was assumed that the
probability mass functions are peaked at the expected value and are smooth in its
vicinity.  A sample problem was solved to illustrate the procedure.  It was
observed that the result is sensitive to the element size in the numerical scheme
and the variances and spatial correlations of parameters.  The expected value
of the hydraulic head was found to differ significantly from the results that would
have been obtained if the problem had been solved deterministically.


78:02F-026
THE CARBON ISOTOPE GEOCHEMISTRY OF A SMALL GROUNDWATER SYSTEM IN NORTHEASTERN
ONTARIO,
Fritz, P., Reardon, E.J., Barker, J., Brown, R.M., and Cherry, J.A.
Waterloo University, Waterloo, Ontario, Canada, Department of Earth Sciences.
Water Resources Research, Vol. 14, No. 6, p 1059-1067, December, 1978.  5 fig,
5 tab, 23 ref.

Descriptors:  Isotope studies, Carbon, Geochemistry, Carbon dioxide, Carbonate
rocks, Groundwater, Crystalline rocks, Isotope fractionation, Canada.

The carbon isotopic composition (13C and 14C) of the inorganic carbon dissolved in
the waters of a small, largely unconfined aquifer in unconsolidated sediments on
the Canadian Shield was investigated.  Three principal carbon sources were
recognized:  soil C02, rock carbonate, and biogenic C02.  The average delta-13C
value of the soil C02 was close to -21.0 ± 1.5, and present-day 14C activities
of the soil C02 varied between 130 and 162% modern 14C.  Very minor amounts (<1.0%)
of carbonate minerals were present within the aquifer and reacted with this soil
C02 to produce a dissolved inorganic carbon  (DIG) with 14C activities which were
as much as 50% below the initial activities of the soil CO2.  The third carbon
source, a biogenic C02, could be detected only indirectly, and its presence was
primarily deduced from the occurrence of methane in the deeper parts of these
aquifers.  The large isotope fractionation which occurred during bacterial co-
production of CO2 with this methane resulted, however, in a 13C-rich CO2 and thus
a DIC with high delta-13C values.  Since the origin of the destroyed organic
matter was not known, no assessment of the importance of this CO2 for the 14C
contents of the DIC was possible.


78:02F-027
DELAYED AQUIFER YIELD AS A PHENOMENON OF DELAYED AIR ENTRY,
Bouwer, H., and Rice, R.C.
United States Water Conservation Laboratory, Science and Education Administration,
United States Department of Agriculture, Phoenix, Arizona  85040.
Water Resources Research, Vol. 14, No. 6, p 1068-1074, December, 1978.  8 fig,
10 ref, 6 equ.

Descriptors:  Water table aquifers, Aquifer testing, Vadose water, Air entrainment,
Pore water, Drawdown, Specific yield, Pumping, Groundwater, Laboratory tests.

Delayed release of pore water from a pumped, unconfined aquifer is treated as a
situation of restricted air movement in the vadose zone due to layers of high
water content.  This restricted movement produces below-atmospheric pressures in
the pore air above the water table, which cause the water table initially to drop
faster than the dewatered zone.  The initial yield thus is less than the full
specific yield, which develops after a certain water table drop.  Equations were
derived that relate delayed yield to air entry value and height above water table
of saturated layers in the vadose zone.  These equations agreed with results from
a delayed yield experiment on a vertical soil column and produced ratios between
initial and final yield that resembled those calculated by others from actual
pumping tests.  An axisymmetric flow system, simulated by interconnected jars with
narrow standpipes, produced delayed yield drawdown curves that were amendable
to Boulton's analysis.
                                      25

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78:02P-028
SUBSURFACE DRAINAGE IN SOILS WITH HIGH HYDRAULIC CONDUCTIVITY LAYERS,
Tang, Y.K., and Skaggs, R.W.
North Carolina State University, Raleigh, Department of Biological and Agricultural
Engineering.
Transactions of the American Society of Agricultural Engineers, Vol. 21, No, 3,
p 515-521, May-June, 1978.  16 fig, 20 ref.

Descriptors:  *Subsurface drains, *Hydraulic conductivity, *Soils, Groundwater
movement, Water table aquifers, Drains, Mathematical models, Equations, Head loss,
Saturated flow, Computer models.

The Richards equation for two-dimensional, saturated-unsaturated flow during
drainage was solved for layered soils using finite difference methods.  -Solutions
were obtained for soils in which the deeper layer has a higher hydraulic con-
ductivity than the surface layer.  Solutions were presented to show the distribu-
tion of equipotential lines and position of the water table during drainage pro-
cesses.  When the drain depth is increased so that it is closer to the high con-
ductivity layer, head loss due to convergence near the drain is reduced.  Thus,
deeper drains may significantly increase drainage rates, even if the hydraulic
head at the outlet remains unchanged.  This effect is larger for deep profiles
and narrow drain spacings than for shallow profiles and wide spacings.  The
effect of increasing the drain depth also increases with the hydraulic conductivity
of the bottom layer.  When outlet conditions are limiting, the most efficient
drain depth is that of the layer interface.  Solutions for various cases showed
that further increasing the depth had only a slight effect on water table drawdown.
                                      26

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                                 SECTION VII


                                 WATER CYCLE

                          WATER IN SOILS (GROUP 02G)


78:02G-001
NUMERICAL STUDY OF QUASI-ANALYTIC AND FINITE DIFFERENCE SOLUTIONS OF THE SOIL-
WATER TRANSFER EQUATION,
Hayhoe, H.N.
Department of Agriculture, Ottawa, Ontario, Canada.
Soil Science, Vol. 125, No. 2, p 68-74,  February, 1978.  3 fig, 3 tab, 9 ref.

Descriptors:  *Infiltration, *Soil water movement, *Wetting, *Model studies,
Soil water, Moisture content, Mathematical models, Analytical techniques,
Equations, Soil science.

The special case of horizontal infiltration of water into a dry soil was
utilized to study the problem of using standard finite differencing with an
economic grid refinement to locate the wetting front accurately.  The procedure
used to determine an average value on grid subintervals for the strongly
concentration-dependent soil-water diffusivity was identified as being a criti-
cal factor in accurately approximating the moisture profile.  New averaging
techniques were proposed which were shown to locate the steep front with sig-
nificantly more accuracy.  The exact solution was required as a basis for this
study.  To meet this need, a quasi-analytic technique was introduced and shown
to be effective through numerical experiments and comparison with an alternative
scheme.


78:02G-002
BOUNDARY CONDITIONS IN MODELING WATER FLOW IN UNSATURATED SOILS,
Zaradny, H.
Polish Academy of Sciences, Gdansk. Institute of Hydraulic Research.
Soil Science, Vol. 125, No. 2, p 75-82,  February, 1978.  11 fig, 20 ref.

Descriptors:  *Soils, *Model studies, *Soil water movement, *Unsaturated soils,
Flow, Mathematical models, Moisture content, Sands, Boundaries  (property),
Equations.

Simultaneous physical and mathematical modeling was employed to prove that the
Richards equation holds true for problems of water flow in unsaturated sand
soils.  This was shown through good agreement between computation results and
data obtained from a physical model.  Fine sand was used in the model, and
changes in the water content were measured with Am 241.  Good results were
obtained upon assuming the boundary condition along the supply line to be in the
form of the x-derivative of water content.  It also was found that the widely
accepted boundary condition, namely that water content is constant at the supply
boundary, can bring about erroneous conclusions.  Good efficiency was achieved
in the computations upon the assumption of a time variable increment which can
be determined with a criterion derived through numerical experiments.


78:02G-003
THE USE OF DYNAMIC SOIL WATER CHARACTERISTICS IN A NUMERICAL DESORPTION MODEL,
Watson, K.K., and Whisler, F.D.
Mississippi Agricultural and Forestry Experiment Station, Mississippi State.
Soil'Science, Vol. 125, No. 2, p 83-91,  February, 1978.  6 fig, 11 ref.

Descriptors:  *Soil water, *Pressure head, *Soil water movement, *Model studies,
Soils, Mathematical models, Water table, Drainage, Desorption, Hysteresis.
                                     27

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A numerical solution of the gravity drainage to a water table of an initially
saturated column of porous material was used to examine the results of experi-
mental studies where the volumetric water content  (theta) during desorption was
found to be dependent on both the soil water pressure head  (h) and the rate of
change of h with time (dh/dt).  In keeping with the experimental findings, the
h(theta) relationship was made space-dependent, and the water content and soil
water pressure head profiles for this case were compared with the results ob-
tained for two analyses in which the h(theta) relationship was held constant
during drainage.  These comparisons indicated that the water content profile
is generally an insensitive measure of h(theta) variations.  The relationship
between h and dh/dt for specified theta values was determined from the space-
dependent h(theta) analysis and compared with the shape of the curves reported
in the experimental studies.


78:02G-004
THEORETICAL MODELING OF MIXED-ELECTROLYTE SOLUTION FLOWS FOR UNSATURATED SOILS,
Bresler, E.
Agricultural Research Organization, Bet Dagan, Israel,  Division of Soil
Physics.
Soil Science, Vol. 125,  No. 4, p 196-203,  April, 1978.  20 ref.

Descriptors:  *Mathematical models, *Unsaturated flow, *Salts, *Soils,
Theoretical analysis,  Equations, Calcium, Sodium, Convection, Diffusion.

A mixed salt solution with ions that interact with the soil matrix are important
in field problems involving the simultaneous flow of water and mixed Na-Ca salts
in unsaturated soils.  Governing partial differential equations describing tran-
sient, one-dimensional,  simultaneous transfer of mixed anions, cations, and
water were formulated, taking into account physicochemical interaction between
mono and divalent ions and the soil matrix.  Effects of convection, diffusion,
mechanical dispersion, anion exclusion,  cation exchange and adsorption, and
coupling phenomena were considered jointly.  Soil-interacting and coupling para-
meters were estimated theoretically from mixed-ion diffuse double-layer theory,
taking into account tactoids, capillarity, and hydrodynamic considerations.  The
coupling-interacting parameters included:  osmotic efficiency coefficient, anion
exclusion, cation exchange equilibria, soil water retentivity, 'and unsaturated
hydraulic conductivity and their dependence on soil water content and soil
solution concentration and composition.   A finite difference approach that
eliminates numerical dispersion was used to approximate the nonlinear partial
differential equations and the boundary conditions appropriate to infiltration,
redistribution, drainage, and evaporation of soil water.  A brief computational
scheme concluded the paper.


78:02G-005
A SOIL COLUMN TENSION LYSIMETER THAT MINIMIZES EXPERIMENTAL EDGE EFFECTS,
Cronan, C.S.
Dartmouth College, Hanover, New Hampshire, Department of Biological Sciences.
Soil Science, Vol. 125,  No. 5, p'306-309,  May, 1978.  2 fig, 2 tab, 12 ref.

Descriptors:  *Lys±meters, *Leachate, *Soil chemistry, "Infiltration, *Perco-
lation, *Tension lysimeter, *Edge effects, Instrumentation, Infiltrometers,
Runoff.

A new tension lysimeter, intended for use with isolated, undisturbed soil'
columns, has been developed.  This lysimeter offers the following advantages:
it is inexpensive; it minimizes problems associated with experimental edge
effects; it is essentially chemically inert; and it permits sampling both
saturated and unsaturated flow in soil leaching experiments.  Data were pre-
sented to illustrate the relatively low variability observed in flow .volumes
and leachate chemistry between replicate undisturbed soil columns receiving
identical treatments.


78:02G-006
SOLUTE TRANSPORT THROUGH SOIL WITH NONUNIFORM WATER CONTENT,
DeSmedt, F., and Wierenga, P.J.
                                      28

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New Mexico State University, University Park, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 1, p 7-10, January-
February, 1978.  4 fig, 16 ref.

Descriptors:  *Solutes, *Soil water movement, *Moisture content, *Model studies,
Mathematical models, Theoretical analysis. Analytical techniques, Equations,
Soil water, Leachate.

An approximate analytical solution was presented for steady flow of salt through
soil with a nonuniform distribution of the water content.  The solution was in
good agreement with a numerical computer solution provided by the CSMP simula-
tion language.  Both solutions also agreed with the analytical solution for
soils with a uniform distribution of the water content.  It was shown that
effluent curves from soil profiles, with the same average water content and
leached at the same steady rate, are basically the same and thus independent of
the variation of the water content in such profiles.


78:020-007
TRANSIENT-AND STEADY-FLOW EXPERIMENTS TESTING THEORY OF WATER FLOW IN SATURATED
BENTHONITE,
Smiles, D.E.
Commonwealth Scientific and Industrial Research Organization, Canberra City,
Australia, Division of Environmental Mechanics.
Soil Science Society of America Journal, Vol. 42, No. 1, p 11-14, January-
February, 1978.  5 fig, 1 tab, 12 ref.

Descriptors:  *Soil water movement, *Flow, *Model studies, Mathematical models,
Laboratory tests, Stratified flow. Steady flow, Unsteady flow, Darcy's law,
Clays.

The theory of water flow in a saturated, swelling clay has been criticized
recently.  This criticism concerns possible effects on the material character-
istics of particle re-orientation during transient flow, as well as suggestions
that the flux equation  (Darcy's law) may be inappropriate to such systems.  This
paper examined these problems by comparing data from transient-and steady-flow
experiments with bentonite.  The data from all experiments are mutually con-
sistent within the experimental error.  It was concluded that Darcy's law is
valid for this material and that the conductivity/water content, and water
content/suction relationships are well defined.


78:020-008
DISPERSION IN SOIL COLUMNS:  EFFECT OF BOUNDARY CONDITIONS AND IRREVERSIBLE
REACTIONS,
Parlange, J.-Y., and Starr, J.L.
Connecticut Agricultural Experiment Station, New Haven.
Soil Science Society of America Journal, VoL 42, No. 1, p 15-18, January-
February, 1978.  4 fig, 17 ref.

Descriptors:  'Dispersion, *Soils, *Model studies, 'Mathematical models, Adsorp-
tion, Convection, Diffusion, Soil water, Solutes, Aqueous solutions.

A closed form approximate analytical solution was provided which describes the
transport of a solute  in a soil column.  The effects of convection, dispersion,
and adsorption were  included.  The latter can include both linear adsorption and
first-or zero-order  reactions.  The effect of the finite length of a soil column
on the miscible displacement of the solute was discussed in detail.  It was
shown in particular  that the standard solution used in the past is accurate to
describe the breakthrough curve but not the profile within the column.


78:020-009
STEADY-STATE SOLUTE  CONVECTION IN TWO DIMENSIONS WITH NONUNIFORM INFILTRATION,
Batu, V., and Gardner,  W.R.
Wisconsin University,  Madison, Department of Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 1, p 18-22, January-
February,  1978.  6 fig, 16 ref.
                                      29

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Descriptors:   *Solute, *Percolation, *Infiltration,  *Model  studies, Mathematical
models. Soil water, Soil water movement. Flow, Unsaturated  flow, Non-uniform
flow.

The steady-state unsaturated flow equation  in two dimensions was solved for an
exponential unsaturated conductivity using  the Kirchhoff transformation.
Streamlines, travel times, and isochrones were calculated for an infiltration
rate which is  a piece-wise linear function  of horizontal coordinate.  Results
were compared  with the equivalent solutions for a saturated soil.  In addition
to solutions in dimensionless form, an example was presented for Plainfield
sand.  The results confirmed that surface variations in infiltration rate may
be propagated  to a considerable depth, particularly  in sandy soils.  This may
account, in part, for the variability in solute leaching frequently observed in
the field.


78:02G-010
EFFECTS OF CLAY TYPE AND CONTENT, EXCHANGEABLE SODIUM PERCENTAGE, AND ELECTRO-
LYTE CONCENTRATION ON CLAY DISPERSION AND SOIL HYDRAULIC CONDUCTIVITY,
Frenkel, H., Goertzen, J.O., and Roades, J.D.
Agricultural Research Service, Riverside, California, Salinity Lab.
Soil Science Society of America Journal, Vol. 42, No. 1, p  32-39, January-
February, 1978.  9 fig, 2 tab, 31 ref.

Descriptors:   *Hydraulic conductivity, *Electrical conductance, *Soils, *Clays,
Laboratory tests, Soil water movement, Soil water, Alkaline soils, Leachate,
Salts.

The hydraulic  conductivities and gradients  along soil columns packed with mont-
morillonitic,  vermiculitic, and kaolinitic  soils adjusted to different levels of
exchangeable sodium were determined at different salt concentrations.  The data
showed that plugging, of pores by dispersed  clay particles is a major cause of
reduced soil hydraulic conductivity for surface soils irrigated with sodic
waters.


78:02G-011
MULTIPLE TENSIOMETER FLUSHING SYSTEM,
Huber, M.J., and Dirksen, C.
Agricultural Research Service, Riverside, California, Salinity Lab.
Soil Science Society of America Journal, Vol. 42, No. 1, p  168-170, January-
February, 1978.  1 fig, 5 ref.

Descriptors:   *Tensiometers, *Soil water, *Instrumentation, Equipment, Valves,
Air, Bubbles,  Irrigation, Soil science, Flushing.

A system for simultaneous flushing of a large number of tensiometers was
described.  It includes a multiple shutoff valve and a manometer with movable
bottom.  Flushing procedures were described; they are fast and simple.  It can
be used with any direction of installation of tensiometers or tubing, for in-
stance, when all tubing is kept below the soil surface to reduce temperature
fluctuations.  A concentric tubing arrangement reduces air diffusion into the
measuring tubing.  The system offers potential for improved data quality and
reduced need for flushing.


78:026-012
HYDRODYNAMIC DISPERSION DURING ABSORPTION OF WATER BY SOIL,
Smiles, D.E., Philip, J.R., Knight,  J.H., and Elrick, D.E.
Commonwealth Scientific and Industrial Research Organization,  Canberra,
Australia,  Division of Environmental Mechanics.

Descriptors:  *Dispersion, *Soil water movement,  *Solutes,  *Absorption, Labora-
tory tests, Leaching, Unsteady flow, Unsaturated flow, Soil water,  Salts.

An experimental study is reported of hydrodynamic dispersion of low concentra-
tion solutions during absorption into horizontal columns of soil with initially
uniform moisture and solute contents.  The initial soil solutions were of rela-
tively high salt concentration.   It was found that both the water and salt


                                      30

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concentration profiles preserved similarity in terms of distance divided by the
square root of time.  This observation implies that the longitudinal dispersion
coefficient is insensitive to pore water velocity and may be taken as a function
of the volumetric water content only, at least for a given initial (low) mois-
ture content.  The formulation which follows is frankly phenomenological.  It
provides a simple means of predicting dispersion during flow in unsaturated soils
which promises to be sufficiently accurate for most purposes.


78:02G-013
PERINENT CRITERIA FOR DESCRIBING THE DISSOLUTION OF GYPSUM BEDS IN FLOWING WATER,
Keisling, T.C., Rao, P.S.C., and Jessup, R.E.
Goergia Coastal Plain Experimental Station, Tifton, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 2, p 234-236, March-April,
1978.  1 fig, 4 ref.

Descriptors:  *Gypsum, *Dissolved solids, *Mass transfer, *Dissolution, Model
studies, Mathematical models, Solutes, Flow, Dispersion, Erosion.

The equation for convective-dispersive solute transport in porous beds and the
continuity equation were used to derive a relationship describing the dissolu-
tion of gypsum beds in flowing water.  The parameters involved in the derived
relationship were:  bed length, solution flow velocity, dispersion coefficient,
mass transfer rate coefficient, and gypsum fragment size.  The proposed rela-
tionship was compared with previously published data and shown to be valid.  A
potential practical field application of the procedure was presented.


78:02G-014
CALIBRATION STABILITY AND RESPONSE TIME FOR SALINITY SENSORS,
Wood, J.D.
Agricultural Research Service, Riverside, California, Salinity Laboratory.
Soil Science Society of America Journal, Vol. 42, No. 2, p 248-250, March-April,
1978.  1 fig, 4 tab, 14 ref.

Descriptors:  Instrumentation, *Salinity, *Saline, soils, Calibrations, Equipment,
Laboratory tests,' Stability, Electrical conductance, Measurement, Soil science.

Commercially produced salinity sensors removed from field and lysimeter experiments
lasting from three  to five years were tested for calibration stability relative to
the original factory calibration.  Significant changes in calibration occurred in
up to 14% of the sensors after four and five years of use.  Response to a step-
change in salinity  also was examined for commercial units in a field installation.
Calculated response factors were lower than those  found in a previous laboratory
experiment.  However, response was sufficiently rapid to assure accurate readings
if changes in salinity occur in time intervals exceeding five days.


78:02G-015
APPROXIMATE ANALYTICAL SOLUTION FOR SOLUTE FLOW DURING INFILTRATION AND REDISTRIBUTION,
De Smedt, P., and Wierenga, P.J.
New Mexico State University, Las Cruces, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42,  No. 3, p 407-411, May-June,
1978.  5 fig, 3 ref, 20 equ.

Descriptors:  Analytical techniques, Dispersion, Soil water movement, Solutes,
Infiltration, Simulation analysis, Hydrodynamics,  Unsaturated flow, Numerical analysis.

An approximate  analytical solution is developed  to describe  solute flow in soil
during infiltration and redistribution.  For  the  solution it is assumed that
hydrodynamic dispersion is  linearly  related  to the pore water velocity.  In
order>to use the solution it is necessary  to  estimate the solute  penetration
depth.  Methods of  estimating  the solute penetration depth are discussed.
Solute concentration distributions computed with  the approximate  analytical
solution are compared with  those obtained with a  numerical model.  It is shown
that the solution proposed  is  most useful during  the infiltration phase.  Dur-
ing  the  redistribution phase the approximate  analytical solution  provides a
                                       31

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 first-order  estimate  of  the  solute  distribution with  time  and  depth.   Computed
 chloride  distributions compare  favorably with  chloride  concentrations  observed
 by  Warrick et  al.   (1971).


 78:02G-016
 SOIL WATER FLOW MODEL WITH TWO-DIMENSIONAL  AUTOMATIC  GAMMA RAY ATTENUATION
 SCANNER,
 Dirksen,  C., and Huber,  M.J.
 Science and  Education Administration,  Riverside,  California, Salinity  Laboratory.
 Water  Resources Research, Vol.  14,  No.  4, p 611-614,  August, 1978.   2  fig,  17
 ref.

 Descriptors:   *Soil water movement,  *Moisture  content,  laboratory  tests,
 *Instrumentation, Model  studies, Soil  water, Gamma rays, Moisture meters, Soil
 moisture  meters, Automation.

 Described is a physical  laboratory  model to study two-dimensional transient
 water  and solute transport in unsaturated soil, including  water uptake by roots.
 It  features  an automatic two-dimensional gamma ray attenuation scanner for  mea-
 suring soil water content.  Automation is obtained with a  simple closed  loop
 control circuit.  After  a gamma count  is transmitted  to the teletypewriter, a
 signal is sent to the hydraulically moved scanner to  search for the next grid
 point.  Upon arrival, the scanner sends a signal  back to initiate another data
 acquisition  sequence, and so on.  In this way, synchronization between counter
 and scanner  is assured independent  of  counting time,  travel time, configuration
 of  grid points, temporary slowdown,  etc.  It also eliminates dead time between
 grid points  for any recording pattern.  Grid points are established by an array
 of  holes  that  trap the core of a solenoid actuator.   The configuration of grid
 points can be  changed easily by opening and closing the desired holes.   This
 mechanical trapping was  found to be  simpler and more  accurate  than  a potentio-
 metric control.  The  soil water flow model  is  constructed  in modules.  It can be
 used as one unit of 3.15 by 1.07 by  0.178 m and inclined up to 30 degrees,  or it
 can be subdivided into up to eight  compartments,  each with its own  drainage
 filter tubes.  The front glass walls allow  visual.observations of soil packing,
 wetting fronts, root  distribution,  etc.  The back aluminum walls allow installa-
 tion of instruments,  such as tensiometers,  salinity sensors, and psychrometers.


 78:026-017
 LINEARIZED MOISTURE FLOW WITH LOSS AT THE SOIL SURFACE,
 Lomen, D.O., and Warrick, A.W.
 Arizona University, Tucson, Department of Soils,  Water  and  Engineering.
 Soil Science Society  of  America Journal, Vol.  42, No. 3, p  396-399, May-June,
 1978.  2  fig,  8 ref,  12  equ,

 Descriptors:   Soil water movement, Unsaturated flow,  Evaporation.

 The general solution  of  a linearized moisture  flow equation is  derived for  point
 and line  sources whether buried or on the soil surface.  The surface flux is
 taken  to  be proportional to the matric flux potential, which is consistent with
 the physical situation of small evaporative losses for dry  soil and larger
 losses for wet soil.  The fraction of water lost  at the surface turns out to be
 identical for  point and  line sources and for the  steady-state  case is  (m/(2+m))
 exponent  (-alpha d)  where m is the surface  flux proportionality constant, d the
 depth  of  source, and  alpha a constant from  the assumed unsaturated hydraulic
 conductivity function.   This fraction is plotted  as a function  of time for a
 fixed  source depth.   Also given are  curves depicting  the total water loss as a
 function  of source depth.  A generalized solution is  derived for any type of
 source located in a horizontal plane.


 78:02G-018
HYDRAULIC CONDUCTIVITY OF SOILS:  UNIFIED APPROACH TO THE STATISTICAL MODELS,
Mualem, Y.,  and Dagan, G.
Colorado  State University, Fort Collins, Department of Civil Engineering.
Soil Science Society of America Journal, Vol. 42,  No. 3, p  392-395,  May-June,
 1978.  12 ref.
                                      32

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Descriptors:  *Hydraulic conductivity, *Soils, *Statistical models, Unsaturated
flow, Porous media, Soil moisture. Pore pressure, Equations, Mathematical
models, Darcy's law.

Conceptual theory of the hydraulic conductivity of unsaturated porous media was
presented.  This analysis permits the systematic derivation of the models of
E.G. Childs and N. Collis George, M.R.J. Wyllie and G.H.F. Gardner, and Y.
Mualem, as well as other existing and new versions, from common statistical
principles.  The resulting formulas of unsaturated hydraulic conductivity can be
classified into three categories:  (1) universal formulas independent of the soil
type which result from extremely simplifying assumption;  (2) formulas with one
degree of freedom, and (3) formulas with two degrees of freedom.  The latter two
types of equations result from accounting for the correlation between pores and
the tortuosity of flow path.  These formulas can be adjusted to soil type to
represent better the variability of soil properties and to increase the accuracy
of the predicted hydraulic conductivity.  However, in this stage it is a poten-
tial advantage only.  Empirical study should be followed in order to derive the
optimal methods of estimating the unknown parameters.


78:02G-019
LEACHING CHARACTERISTICS OF A LAYERED FIELD SOIL,
Starr, J.L., DeRoo, B.C., Frink, C.R., and Parlange, J.Y.
Connecticut Agricultural Experiment Station, New Haven.
Soil Science Society of America Journal, Vol. 42, No. 3, p 386-391, May-June,
1978.  8 fig, 18 ref.

Descriptors:  *Groundwater movement, *Percolating water, *Soil physical proper-
ties, Infiltration,.Soil chemistry. Leaching, Solutes, Soil water movement,
Saturated flow.

Two ponded flow experiments were conducted to study the leaching characteristics
of a layered field soil, fine sandy loam over coarse sand, with a water table at
a depth of 1.8 m.  In the first experiment, a steel cylinder 1.8 m in diameter
was driven into a soil to a depth of 3.6 m.  Infiltrations of water and dye pro-
vided the means for direct observation of the effect of air entrapment upon the
rates of infiltration as well as the primary pattern of water flow through the
coarse subsoil.  The rate of infiltration was observed to increase by nearly two-
fold when the entrapped air between the saturated surface layer and the shallow
groundwater table was vented directly to the atmosphere.  Removal of the soil
layers following infiltration of a dye solution showed that most of the infil-
trating water moved through fingers ranging from 5 to 20 cm in diameter. . In the
second experiment, chloride distributions at six depths were measured following
the application of a pulse of 0.3N CaC12 solution to the soil surface.  Chloride
movement for the 20- to 60-cm soil depths averaged about 50% slower than that
determined from the average pore-water velocity at the soil surface.  In contrast
to this relatively low rate of chloride movement, several salt pulses reached the
120- and 180-cm depths soon after or before reaching the 60-cm depth.  This
greatly increased flow rate corresponds to the observations in the first experi-
ment where flow became unstable and the solute moved in fingers of flow below tine
60-cm depth.


78:02G-020
AN ANALYSIS OF SENSIBLE AND LATENT HEAT FLOW IN A PARTIALLY FROZEN UNSATURATED
SOIL,
Fuchs, M., Campbell, G.S., and Papendick, R.I.
Washington State University, Pullman, Department of Agronomy and Soils.
Soil Science Society of America Journal, Vol. 42, No. 3, p 379-385, May-June,
1978.  5 fig, 2 tab, 15 ref, 36 equ, 2 append.

Descriptors:  Frozen soils, Heat flow, Freezing, Thawing, Solutes, Latent heat,
Thermal conductivity.                              ,


A heat flow theory has been developed which can be used to predict freezing and
thawing cycles of a temperate soil.  The latent heat of fusion is incorporated
into the classical heat flow equation with the heat capacity and the thermal
                                       33

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conductivity of the soil modified to include terms which  account  for  the phase
transformation.  Computations for a Palouse silt loam  soil  show that  the ice-
liquid phase transformation occurs over a defined temperature range where the
apparent heat capacity and the apparent thermal conductivity may  take on values
which are several orders of magnitude larger than those either in the unfrozen
or in the near completely frozen soil.  The computations  also indicate  that
the presence of solutes in the soil water significantly lowers the temperature
range over which the freeze-thaw zone develops and may allow considerable
transport of water and heat at lower temperature than  in  the absence  of solutes.


78:020-021
A METHOD OF PROMOTING PENETEATION OF WATER INTO TIGHT, SLOPING SOIL UNDER DRIP
IRRIGATION,
Hillel, D.
University of Massachusetts, Amherst, Department of Plant and Soil Science.
Soil Science, Vol. 125, No. 5, p 329-330, May, 1978.   1 fig.

Descriptors:  Irrigation, Infiltration, Penetration, Runoff, Evaporation, Root
zone. Gravels, Methodology.

A method is proposed to increase penetration of water  into  the root zone, as
well as to reduce runoff and evaporation by means of gravel-filled pits under
each emitter when drip irrigation is applied to sloping ground of  low infil-
trability.  A sample calculation is provided to help determine the optimal
dimensions of the gravel pits.


78:02G-022
FRONTAL MOVEMENT OF AQUEOUS SOLUTIONS DURING REDISTRIBUTION THROUGH AIR-DRY SAND
COLUMNS AS A FUNCTION OF COLUMN LENGTH AND TIME,
Routson, R.C., and Brown, D.J.
Battelle Pacific Northwest Laboratories, Richland, Washington.
Soil Science, Vol. 125, No. 5, p 320-325, May, 1978.   5 fig, 3 tab, 19  ref.

Descriptors:  *Aqueous solutions, *Sands, *Laboratory  tests, *Soil water move-
ment, Sorption, Soils, Depth, Graphical analysis, Equations, Wetting.

The frontal movement during redistribution of unsorbed waste fronts through an
air-dried sand was measured as a function of time and  column length for columns
25-200 cm long.  All column data fit an equation of the form S = Ex T to the F
power.  S was found to be significantly correlated with T (at the  1%  level).
The equation was normalized by dividing S and E by the column length.  When this
was done, data for all columns fit a single normalized equation.   Use of this
equation allows estimation of the shortest possible time necessary for  the front
of a pulse of waste solution to reach a given depth in a homogeneous  soil
system.


78:02G-023
EXCHANGEABLE SODIUM AND SOIL WATER BEHAVIOR UNDER FIELD CONDITIONS,
Acharya, C.L., and «Abrol, I.P.
Central Soil Salinity Research Institute, Karnal, India.
Soil Science, Vol. 125, No. 5, p 310-319, May, 1978.   9 fig, 1 tab, 15  ref.

Descriptors:  *Sodium, *Soil management, *Alkaline soils,  "Irrigation water,
*Soil chemical properties, Infiltration, Permeability, Soil analysis, Leaching,
Land reclamation.

The effect of exchangeable sodium on soil water behavior under field conditions
was investigated in five differentially gypsum treated plots of a highly sodic
soil.  The soil is representative of the sodic soils of the Indo-gangetic plains
in northern India.  The soil texture is sandy loam in the surface  0-15 cm, and
the clay fraction is dominantly illitic.  Exchangeable sodium percentage (ESP)
varied from 4 to 38 in 0-15 cm,  and 28 to 88 in the 15-30 cm layer.  Basic in-
take rate of the soil increased from 8.7 mm per day in soil of highest ESP to
about 25 mm per day in soil of lowest ESP.  Higher basic intake rate and in-
creased retention at low suctions resulted in greater profile water storage.
                                      34

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Soil water diffusivity values  (D) calculated from the water distribution
following evaporation showed that at a water content of  0.22 cu cm/cu while D
 (sq cm/day) decreased from 34  to 26 when ES.P increased from 4 to  11, the D value
sharply decreased to 8 with a  further rise in ESP to 16.  Improvement in trans-
mission characteristics resulting from lowered ESP was reflected  in the drying
pattern of soils.  The first stage of drying was delayed in low ESP treatments
compared to the high ESP treatment because of regular movement of water from
lower layers to the surface to meet the evaporation demand.  The effect of
treatments on water movement was noticeable to a depth of 90 cm studies in these
experiments, although the improvement in layers below 15 cm was very small in
treatments receiving lower doses in gypsum.


78:02G-024
COMPACTION EFFECTS ON THE HYDRAULIC CONDUCTIVITY OF A CLAY SOIL,
Douglas, E., and McKyes, E.
Macdonald College, Ste. Anne de Bellevue, Quebec, Canada, Department of
Agricultural Engineering.
Soil Science, Vol. 125, No. 5, p 278-282, May, 1978.  6  fig, 7 ref.

Descriptors:  *Compaction, *Compacted soils, *Hydraulic conductivity, *Clays,
Unsaturated flow, Laboratory tests, Equations, Saturated soils, Porosity,
Pressure.

Unsaturated hydraulic conductivities of laboratory-compacted samples of Ste.
Rosalie clay were measured, and the values obtained were corrected for the
effective changing porosity under increasing pressure gradients.  An equation
was presented that permits predicting the corrected hydraulic conductivity as a
function of compaction in terms of porosity.


78:02G-025
USE OF METHANOL-WATER SOLUTIONS FOR FREEZE PROTECTION OF TENSIOMETERS,
Wendt, C.W., Wilke, O.C., and New, L.L.
Texas A & M University, Lubbock, Agricultural Research and Extension Center.
Agronomy Journal,' Vol. 70, No. 5, p 890-891, September-October, 1978.  2 fig, 1
tab.

Descriptors:  Frozen soils, Freezing, Tensiometers, Irrigation, Soil water, Soil
water movement.

The use of tensiometers to schedule irrigations has been limited primarily to
summer crops because of water freezing in the tensiometers during the winter
months.  Since methanol-water mixtures have lower freezing points than water, a
greenhouse study was conducted.using an Olton loam soil  (Acridic Paleustolls) to
determine the effect of a methanol-water mixture (30% methanol by volume)  on
tensiometer readings and plant growth.  No major effects of tensiometer readings
or plant growth were noted.  Results from a field demonstration on irrigated
winter wheat (Triticum aestivum L.)  indicate that tensiometers with such
mixtures can be used to estimate soil water tension changes at atmospheric
temperatures down to -18.8 C.


78:020-026
EVALUATION OF PEAT AND GRANULAR INOCULUM FOR SOYBEAN YIELD AND N FIXATION UNDER
IRRIGATION,
Bezdicek, D.F., Evans, D.W.,  Abede,  B., and Witters, R.E.
Washington State University,  Pullman, College of Agriculture Research Center.
Agronomy Journal, Vol. 70, No. 5, p 865-868, September-October,  1978.  1 fig,
5 tab, 15 ref.

Descriptors:  Nitrogen fixation, Carriers,  Soybeans, Peat,  Granules, Symbiosis.

The purpose of this study was to evaluate peat and granular inoculum for effec-
tiveness in nodulation, N fixation,  and yield of soybeans in a soil deficient in
N.  Maximum yield response from inoculation (less control)  was 3,454 kg/ha
(51.4 bu/A)  in 1975 and 2,547 kg/ha (37.9 bu/A)  in 1976.   Total N fixed was
estimated to be as high as 311 and 263 kg/ha in 1975 and 1976, respectively.
                                      35

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 The  proportion of  plant N derived  from N  fixation  ranged  from 71  to 80%.
 Estimates  of  total N  fixed based on  acetylene  reduction were  half of those
 based  on total plant  N.  In general, higher  soybean  yield and better nodulation
 were obtained with the granular than peat carriers,  although  in these instances,
 higher-than-recommended rates of granular carriers were used.  These studies
 show that  soybeans are capable of  fixing  over  300  kg/ha of N,  an  amount which  is
 considerably  higher than that reported elsewhere.  The data suggest that  in
 soybean-growing areas where 25 to  40% of  the total N is from  fixation, the soy-
 bean symbiotic N-fixing system is  capable of fixing  sufficient N  for yields far
 beyond that now reported.


 78:02G-027
 STUDY  OF THE  RELATIVE EFFICIENCY OF  FINITE DIFFERENCE AND GALERKIN TECHNIQUES
 FOR  MODELING  SOIL-WATER TRANSFER,
 Hayhoe, H.N.
 Department of Agriculture, Ottawa, Ontario,  Canada,   Chemistry and Biology
 Research Institute.
 Water  Resources Research, Vol. 14, No. 1,  p  97-102,  February,  1978.   8 fig, 2
 tab, 14 ref.

 Descriptors:  *Infiltration, *Soil water,  *Soil water movement, *Model studies,
 Mathematical  models.  Numerical analysis,  Analytical  technique, Moisture content,
 Soils, Soil science.

 Horizontal infiltration of water into a dry  soil was used to  study the effi-
 ciency of  finite difference and Galerkin  procedures  in accurately locating the
 steep  wetting front..  The location of the  wetting  front was determined by a
 quasi-analytic solution to Richard's equation.  The  Galerkin  technique was evalu-
 ated by  using linear, Hermite cubic, and  Lagrange quintic elements.  These
 schemes were  compared with the performances  of the Crank-Nicolson central dif-
 ference method where  a standard and a modified averaging  procedure for soil-
 water  diffusivity  on  grid subintervals is  utilized.   The  comparisons  were made
 on the basis  of error as a function of spatial grid  refinement and the relative
 efficiency in achieving a practical  level  of accuracy.  The results  lead to the
 conclusion that the Galerkin scheme with  linear elements  or the finite differ-
 encing scheme with the modified averaging  procedure  is preferable to  the other
 techniques.


 78:02G-028
 VARIABILITY OF HYDRAULIC CONDUCTIVITY WITHIN AND BETWEEN  NINE WISCONSIN SOIL
 SERIES,
 Baker,  F.G.
 Wisconsin University,  Madison, Department  of Soil  Science.
 Water  Resources Research, Vol. 14, No. 1,  p  103-108,  February, 1978.  3 fig, 2
 tab, 17 ref.

 Descriptors:  *Hydraulic conductivity, *Moisture content,  "Variability, *Soil
 types,  *Wisconsin, Soil horizons, Infiltration, Soils, Soil water, Soil water
 movement.

 Hydraulic conductivity was measured in selected subsurface horizons of nine soil
 series by using the crust test method.  Measurements were made for several mois-
 ture potentials in the range 0 to -150 cm  of water at several randomly selected
 sites per soil series.  The morphological  character of the soil series spanned a
 broad  range,  from  sands to clay loam soils.  The hydraulic conductivity charac-
 teristic of each series was described mathematically  and  the series conductivity
 curves  were related as a family of curves.  By using multivariate discriminant
 analysis, the series were grouped.into classes of  similar hydraulic behavior,
based on the dispersion of moisture potential and hydraulic conductivity data
within and between series.   A 95% prediction interval was constructed to include
 the range of conductivities to be expected at future  sites.


 78:02G-029
EFFECT  OF SOIL MATRIC POTENTIAL AND SEEDING DEPTH ON EMERGENCE OF BARLEY,
Sepaskhah,  A.R.,  and Ardekani, E.R.
                                      36

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Pahlavi University, Shiraz,  Iran, Department of  Irrigation.
Agronomy Journal, Vol.  70, No.  5, p  728-731, September-October,  1978.   4  tab
17 ref, 6 equ.

Descriptors:  Barley, Germination, Emerging vegetation  stage, Seeds, Moisture
tension, Crop production, Crop  response.

The effects of soil matric potential and seeding depth  on emergence percent and
rate of emergence of barley were investigated.   Seedling emergence of  'Zarjo'
cultivar of barley was  measured in a Calcixerillic Xerochrept soil at  -0.6 to
-30.0 bars soil matric  potentials and at 2 to 12 cm seedling depths in the
greenhouse.  Cultivar response  to seedling depth was determined  by seedling
emergence measurements  of 'Torsh1, Zargo, and 'Shaneii1 cultivars at seeding
depths of 2 to 12 cm under the  same experimental conditions.  Soil matric poten-
tial of -30.0 bars reduced the  seedling emergence of Zarjo and resulted in the
lowest emergence rate.  However, soil matric potentials of -0.6  and -1.5 bars
also reduced Zarjo emergence at the 12-cm seeding depth.  Seedling emergence and
emergence rate of Zarjo were lower at the 12 cm  seeding depth at all levels of
soil matric potentials.  The emergence rate was  also reduced at  the 8-cm seeding
depth, but only at -30.0 bars.  Seedling emergence of Shaneii was found to be
lower than that of the  Torsh and Zarjo cultivars.  The rates of  emergence of the
cultivars were not greatly different at the various seeding depths.


78:02G-030
ALTERNATE DRYING AND REWETTING  EFFECTS ON CHEMICAL AND PHYSICAL  PROPERTIES AND
MOISTURE-SALINITY RELATIONSHIPS OF A HISTOSOL,
Giskin, M., and Levin,  I.
Agricultural Research Organization, Bet Dagan, Israel, The Volcani Center.
Agronomy Journal, Vol.  70, No.  3, p 445-447, May-June, 1978.  1  fig, 2  tab,
J--? jT6£ *

Descriptors:  Organic soils, Drying, Wetting, Soil management, Soil chemical
properties, Soil physical properties, Moisture content, Electrical conductance.
Irrigation.

The purpose of the study was to investigate the  possible influences on  soil
management of changes in chemical and physical properties resulting from a
Histosol being carried  through  several successive dryings and wettings.  Soil
from the 0 to 30 cm layer of a  low moor Histosol with a pH of 7.6 and organic
matter content of 55.3% was used.  The soil was  put through three successive
cycles of air-drying and rewetting; subsamples were removed at each stage and
physical and chemical determinations were carried out.  The saturation  percent-
age of the field sample decreased from 95.9 to 87.3% after the third drying
cycle.   The electrical  conductivity of the saturation extract decreased at each
drying stage, due to the large differences in the nitrate content between the
dry and wet stages (8 vs. 380 ppm).  Moisture retention curve data showed a 5%
difference in available water between the moist  field sample and the same sample
after air-drying.  The  data showed that laboratory measurements of soil-water
relations for a Histosol change with time, i.e., with each exposure to drying
and rewetting prior to  sampling.  This information will have a direct bearing on
the management of a Histosol.


78:02G-031
SOIL MOISTURE SENSING WITH AIRCRAFT OBSERVATIONS OF THE DIURNAL RANGE OF SURFACE
TEMPERATURE,
Schmugge,  T., Blanchard, B., Anderson, A., and Wang, J.
National Aeronautics and Space Administration, Greenbelt,  Maryland,   Goddard
Space Flight Center.
Water Resources Bulletin, Vol. 14, No. 1, p 169-178, February, 1978.   7-fig.
1 tab,  7 ref.                                                             *

Descriptors:  *Remote sensing, *Soil moisture, *Soil temperature, *Arizona,
Soil surfaces. Temperature, Diurnal, Crops.

Aircraft observations of the surface temperature were made by measurements of
the thermal emission in the 8-14 micrometer band over agricultural fields
                                       37

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around Phoenix, Arizona.  The diurnal range of these surface temperature
measurements was well correlated with the ground measurement of soil moisture
in the 0-2 cm layer.  The surface temperature observations for vegetated fields
were found to be within 1 or 2C of the ambient air temperature, indicating no
moisture stress.  These results indicated that for clear atmospheric conditions
remotely sensed, surface temperatures can be a reliable indicator of soil
moisture conditions and crop status.


78:02G-032
NUTRIENT EFFECTIVENESS IN RELATION TO RATES APPLIED FOR POT EXPERIMENTS:  I.
NITROGEN AND POTASSIUM,
Terman, G. L., and Mortvedt, J.J.
National Fertilizer Development Center, Muscle Shoals, Alabama, Soils and
Fertilizer Research Branch.
Soil Science Society of America Journal, Vol. 42, No. 2, p 297-302, March-April,
1978.  7 fig, 7 ref.

Descriptors:  Fertilizers, Nutrients, Nitrogen, Potassium, Phosphorus, Rates of
application. Greenhouses, Corn (field), Rice, Crop response.

A N source experiment was conducted on infertile Mountview sil  (Typic Paleudult)
to evaluate four N sources at multiple rates of applied N and P.  Granular
ammonium nitrate (AN), sulfur-coated urea (SCU), oxamide (Ox), and isobutylidene
diurea (IBDU) were evaluated for corn (Zea mays L.) at N rates of 0, 400, 800,
and 1,200 mg/pot (5 kg of soil), each at P rates of 0, 60, 120, 480, and 960
mg/pot.  Yield response to applied N was in the order AN » SCU > Ox > IBDU at
the higher rates of applied P.  At 60 and 120 mg of applied P/pot, however, P
was too deficient for satisfactory evaluation of the N sources.  In an experi-
ment with flooded rice (Oryza sativa L.), P limited yields less than did N.  In
other N-P and P-K factorial experiments, rates of other nutrients and length of
growth period also greatly affected crop response to applied N and K.


78:02G-033
NUTRIENT EFFECTIVENESS IN RELATION TO RATES APPLIED FOR POT EXPERIMENTS:  II.
PHOSPHORUS SOURCES,
Mortvedt, J.J., and Terman, G.L.
National Fertilizer Development Center, Muscle Shoals, Alabama, Soils and
Fertilizer Research Branch.
Soil Science Society of America Journal, Vol. 42, No. 2, p 302-306, March-April,
1978.  4 fig, 3 tab, 12 ref.

Descriptors:  Nutrients,  Rates of application, Phosphorus compounds, Fertil-
izers, Greenhouses, Corn (field), Crop response, Crop production.

Three greenhouse pot experiments were conducted with corn (Zea mays L.)  grown on
infertile soils to evaluate four fertilizers as sources of P.  The granular
sources were concentrated superphosphate (CSP, 90% of P water-soluble),  mono-
ammonium phosphate (MAP,  100% of P water-soluble), a mixture of 30% of the P as
CSP and 70% as dicalcium phosphate (DCP, water-insoluble),  and a 10-90% mixture
of CSP and DCP.  yarious rates of P per plot from each source were compared.
These P sources and rates were compared at various levels of N and K.  The order
of effectiveness was the same at all levels of applied N and K:  MAP > CSP > 30%
CSP + 70% DCP > 10% CSP + 90% DCP.  This indicates that on these soils,  P was
the chief limiting nutrient at all levels of N and K,  However, yield levels and
the precision'of determining differences in effectiveness among sources relative
to experimental error increased greatly at higher rates of applied N and K.


78:020-034
RAPID ESTIMATE OF UNSATURATED HYDRAULIC CONDUCTIVITY FUNCTION,
Bresler,  E., Russo, D., and Miller, R.D.
Agricultural Research Organization, Bet Dagan, Israel,  Division of Soil Physics.
Soil Science Society of America  Journal, Vol. 42, No.  1, p 170-172, January-
February, 1978.  4 fig, 10 ref.
                                      38

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Descriptors:  *Hydraulic conductivity, *Unsaturated flow, *Infiltration,
*Estimating equations, Laboratory tests, Soil physical properties, Pore
pressure, Pore water, Horizontal infiltration, Wetting front.

From results of Reichardt, Nielsen, and Biggar and of Russo and Bresler, it was
inferred that a laboratory horizontal infiltration experiment with air-dry soil
yields an estimate of the saturated-unsaturated hydraulic conductivity function
given by K(h) = 0.27(m to the 4th power)(h sub e/h) to the 2.6 power or K(theta)
= 0.27(m to the 4th power)(theta - theta sub d)(theta sub w - theta sub d)) to
the 7.2 power.  Here m = dx/d(t to the 1/2 power); x is distance to the wetting
front and t is infiltration time; theta sub d and theta sub w are water contents
of air-dry and "unsaturated" soil; h is pore water pressure head, and h sub e is
the air entry value of h.  These relationships can serve as a general approxi-
mation of K(theta) and K(h)  in nonsodic stable soils.  Field measurements of h
sub e and saturated K can also be used to derive K(theta) and K(h).


78:02G-035
THE ROLE OF NITRATE DIFFUSION IN DETERMINING THE ORDER AND RATE OF DENITRIFICA-
TION IN FLOODED SOIL:  I. EXPERIMENTAL RESULTS,
Reddy, K.R., Patrick, W.H.,  Jr., and Phillips, R.E.
North Carolina State University, Raleigh, Department of Biological and Agricul-
tural Engineering.
Soil Science Society of America Journal, Vol. 42, No. 2, p 268-272, March-April,
1978.  5 fig, 3 tab, 18 ref.

Descriptors:  Denitrification, Nitrates, Anaerobic conditions, Flooding, Sub-
mergence, Nitrogen, Diffusion, Incubation.

In this study, 15 soils from various locations in the U.S. were amended with
0.5% rice straw and incubated under saturated conditions without 02, either with
no excess floodwater or with a 3-cm overlying layer of floodwater.  The dis-
appearance of added and native N03(-)-N and its conversion to N2 and N20 fol-
lowed apparent zero-order reaction kinetics when all the N03(-)-N was present in
the active soil layer  (no excess floodwater).  When added N03(-)-N was present
in both the  floodwater and the soil layer, N03(-)-N disappearance followed
apparent first-order reaction kinetics.  A decrease in N03(-)-N concentration in
the soil layer caused NO3(-)-N in the floodwater to diffuse  into the soil layer
(a first-order reaction with respect to N03(-)-N concentration) where it was
denitrified.  The rate of denitrification was  faster in  soils incubated with no
excess floodwater compared to soils incubated under 3 cm of  floodwater.  One soil
(Crowley silt loam), when incubated with no added carbon source and no excess
floodwater,  showed N03(-)-N disappearance to follow first-order kinetics.  When
this soil was incubated with an additional carbon  source, NO3(-)-N disappearance
was zero-order.


78:02G-036
THE ROLE OF NITRATE DIFFUSION IN DETERMINING THE ORDER AND RATE OF DENITRIFICA-
TION IN FLOODED SOIL:  II.  THEORETICAL ANALYSIS AND INTERPRETATION,
Phillips, R.E., Reddy, K.R., and Patrick, W.H., Jr.
Kentucky University, Lexington, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 2, p 272-278, March-April,
1978.  7 fig, 13 ref, 12 equ, 1 append.

Descriptors:  Denitrification, Nitrates, Flooding, Submergence, Nitrogen, Diffu-
sion, Theoretical analysis.

A theoretical analysis.of denitrification occurring in submerged soil in a test
tube, when assumed to be a zero-order reaction with available organic carbon
nonlimiting, appears to be a first-order reaction if the effects of diffusion
are neglected.  This is so because denitrification occurs at a faster rate than
the diffusive flux can supply NO3(-j-N to the soil.  After some length of time,
the concentration of NO3(-)-N in the lower portion of the flood-water-soil inter-
face will be equal to the concentration in the flood-water.  After which time,
denitrification occurs only in the upper portion of the  soil sample.  It is
suggested that the true order of reaction and rate constant of denitrification in
a test tube  can be evaluated experimentally by eliminating the floodwater above
                                       39

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the soil sample; with this experimental geometry some of the confounding effects
of diffusion of N03(-)-N can be minimized.  If diffusion is neglected, not only
is the order of reaction misjudged but the depth of floodwater above the soil
has a significant effect on the magnitude of the calculated rate constant of the
apparent first-order reaction also.


78:02G-037
RELATIONSHIP TO EXTRACTABLE SOIL MANGANESE TO SOIL PROPERTIES,
Shuman, L.M., and Anderson, O.E.
Georgia University, Experiment, Department of Agronomy.
Soil Science Society of America Journal-, Vol. 42, No. 4, p 666-667, July-August,
1978.  2 tab, 8 ref.

Descriptors:  Manganese, Soil chemical properties, Soil physical properties,
Ammonium compounds, Organic matter, Cation e-xchange, Greenhouses, Soil chemistry.

In a greenhouse experiment eight Southeastern soils were amended to give pH
levels of 4.8, 5.8, and 6.8 and were treated with 0, 25, and 50 ppm Mn.  After
growing wheat (Triticum aestivium L.) for 40 days, the soils were extracted for
Mn using six extractants:  H20, neutral IN NH40Ac (with and without 0.2% hydro-
quinone), "double acid", diethylenetriaminepentaacetic acid (DTPA) and ethylene-
diaminedi-o-hydroxyphenylacetic acid (EDDHA).  Except for the low-Mn soils,
greater differences in extractable Mn were observed among soil types and soil pH
levels than among Mn rates.  Extractable Mn was correlated with soil clay con-
tent and total soil Mn.  Organic matter content with a narrow range from 1.0 to
2.9%, silt content and cation exchange capacity (CEC) were not correlated with
extractable Mn.   The extractable Mn decreased as soil pH increased for the H20,
NH40Ac alone, and DTPA extractants making them preferable for predicting soil
Mn availability since higher pH causes Mn to be less available to the plant.


78:02G-038
A SOIL MOISTURE BUDGET MODEL ACCOUNTING FOR SHALLOW WATER TABLE INFLUENCES,
Stuff, R.G., and Dale, R.F.
Purdue University, West Lafayette, Indiana, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 4, p 637-643, July-August,
1978.  9 fig, 1 tab, 15 ref, 10 equ.

Descriptors:  Soil moisture, Evapotranspiration, Capillary water, Water balance,
Field capacity,  Moisture deficit, Computer models, Water table.

Soil moisture balance programs developed on well-drained soils were found to be
unsatisfactory for a soil underlain by shallow water tables, a condition typical
of about 9 million acres of cropland in Indiana.  Capillary rise past a 105-cm
root zone boundary was estimated as the difference between estimated evapotrans-
piration (ET) and changes in soil moisture under corn (Zea mays L.) on a tile-
drained Typic Argiaquoll at West Lafayette, Indiana, during three growing
seasons, 1971-1973.  Capillary water was found to supply an average of 27% of
the ET in periods with little or no precipitation.  Computer model estimates
showed capillary water to furnish about 17% of the total ET over a 100-day
period from 49 days*before silking to 50 days after.  The derived relationships
with those obtained from literature sources and assumptions regarding runoff and
recharge were programmed in a computer model for simulating the daily moisture
conditions.  The model was found to closely track measurements of both soil
moisture and water table depths in four independent seasons:  early and late
plantings in 1970 and 1974.


78:02G-039
SALT OUTFLOWS FROM NEW AND OLD IRRIGATED LANDS,
Carter, D.L., and Robbins, C.W.
Idaho University, Kimberly, Snake River Conservation Research Center.
Soil Science Society of America Journal, Vol. 42, No. 4, p 627-632, July-August,
1978.  3 fig, 3  tab, 13 ref.

Descriptors:  Salinity, Leaching, Leachate, Drainage water, Water quality, Salt
balance, Irrigated land.
                                      40

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Three water application treatments with low salt water were applied to previously
nonirrigated soil and to a similar soil which had been irrigated for 67 years.
The total soluble salt content of these soils initially, and after one and two
seasons of treatment, was measured to determine salt outflow.  Residual soluble
salts were esse.ntially removed from the previously nonirrigated soil after 30 cm
of water/m depth of soil had passed from the soil as leachate, regardless of the
number of seasons required for that amount of leaching.  The total quantity of
residual salt removed from soil 5 m deep was 70 metric tons/ha, with about 38
metric tons/ha being leached out by the first 14 cm of leachate.  After the
residual salt was removed, the salt content of the newly irrigated soil was the
same as that of the soil which had been irrigated for 67 years.  Subsequent salt
outflow from the soil was directly related to the quantity of water leaching
through the soil, indicating .that more minerals dissolved with more leaching.
Soils irrigated for many years and then not irrigated for up to 10 years had no
measurable reaccumulation of soluble salts during the period of nonirrigation.


78:020-040
EFFECTS OF SOIL MOISTURE ON THE DIFFUSION COEFFICIENTS AND ACTIVATION ENERGIES OF
TRITIATED WATER, CHLORIDE, AND METRIBUZIN,
Scott, H.D., and Paetzold, R.F.
Arkansas University, Fayetteyille, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 1, p 23-27, January-
February, 1978.  3 fig, 2 tab, 25 ref.

Descriptors:  *Diffusion, *Soil moisture, *Solutes, Laboratory tests. Moisture
content, Soils, Soil horizons, Adsorption, Radioisotopes, Tritium.

Diffusion coefficients of tritiated water, chloride, and metribuzin were deter-
mined in Captina silt loam as functions of soil water content and soil tempera-
ture.  Tritiated water and metribuzin were found to diffuse in both liquid and
vapor phases, whereas chloride diffusion was restricted to the solution phase.
For a given soil water content, values of the diffusion coefficients were larger
in soil samples from the Ap horizon than in those from the B2t horizon for
tritiated water and chloride.  This was attributed to the greater tortuosity in
the B2t horizon.  Metribuzin had similar diffusion coefficients in both horizons,
apparently reflecting offsetting effects due to the greater adsorption by the Ap
and greater tortuosity in the B2t.  Thermodynamic studies indicated that the
energy requirement for diffusion of these solutes was inversely related to soil
moisture content for tritiated water and metribuzin.  Activation energies for
chloride diffusion were lower than for other solutes at equal soil water contents.


78:020-041
LINEAR AND NONLINEAR MODELS OF INFILTRATION FROM A POINT SOURCE,
Ben-Asher, J., Lomen, D.O., and Warrick, A.W.
Arizona Water Resources Research Center, Tucson.
Soil Science Society of America Journal, Vol. 42, No. 1, p 3-6, January-February,
1978.  6 fig, 11 ref.

Descriptors:  *Infiltration, *Irrigation, *Soil water movement, *Model studies,
Mathematical models. Analytical techniques, Equations, Soils, Soil water, Soil
types.

Numerical and analytical solutions for water flow from a point source were com-
pared.  The numerical solution was for the nonlinear moisture flow equation, and
the analytical solution was for the corresponding linearized form.  For cyclic
conditions, results were approximately the same with regard to range in values
between the wettest and driest values.  However, the numerical results showed a
faster response both for wetting and drying.  Computational times required of the
analytical solution were of the order of 1/20 to l/200th of that required for the
finite difference solutions.


78:026-042
HYDRAULIC CONDUCTIVITY OF UNSATURATED POROUS MEDIA:  GENERALIZED MACROSCOPIC
APPROACH,
Mualem, Y.
                                        41

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Colorado State University, Fort Collins, Engineering Research Center.
Water Resources Research, Vol. 14, No.  2, p 325-334, April, 1978.  2 fig, 5 tab,
41 ref.

Descriptors:  *Hydraulic conductivity,  *Porous media, *Unsaturated flow, *Mathe-
matical models, Equations, Theoretical  analysis, Soil texture, Statistical
models, Porosity, Specific yield.

The macroscopic approach which yields the power function relationship between
the relative permeability and the effective saturation, K sub r = S sub e to the
n power, was generalized to allow n to  vary with the soil type.  Theoretical
analysis shows that n may receive values lower than 3.0 for granular porous
media and higher than 3.0 for soils of  the fine texture.  These findings were
verified by using experimental data of  50 soils.  The lower limit of n was
found to be 2.5, while high values (up  to n = 24.5) were found for the-fine-
textured soils.  Statistical analysis of the measured data of the 50 soil sam-
ples showed a significant correlation between n and w, which indicates the
amount of work per unit volume of soil  required to drain a saturated soil to the
wilting point.  By using the soil characteristics psi-theta, an empirical formula
was derived which relates n to w by n = 0.015w + 3.0.  This proposed model was
compared with the two previous versions of Averjanov and Irmay on the basis of
the experimental data of the 50 soils.  A very good agreement was found between
the measured K sub r - theta curves and the theoretical ones, derived by the new
model, for granular soils as well as for soils of fine texture where the other
models very often fail.  The accuracy of the new model is competitive with the
best of the statistical models analyzed by Mualera.  By this study, the power
function model gains a high degree of accuracy, which compounded by its simpli-
city, produces an efficient tool for prediction of the hydraulic conductivity of
unsaturated soils.


78:02G-043
SOLUTE TRANSPORT DURING ABSORPTION OF WATER BY SOIL:  LABORATORY STUDIES AND
THEIR PRACTICAL IMPLICATIONS,
Smiles, D.E., and Philip, J.R.
Commonwealth Scientific and Industrial Research Organization, Canberra City,
A.C.T. 2601, Australia, Division of Environmental Mechanics.
Soil Science Society of America Journal, Vol. 42, No. 4, p 537-544, July-August,
1978.  4 fig, 1 tab, 14 ref, 21 equ.

Descriptors:  Leaching, Unsaturated flow, Absorption, Scaling, Infiltration,
Capillary action.

An experimental study of solute transport during absorption into uniform
horizontal soil columns is reported.   The inferred dispersion coefficient is
essentially independent also of the volumetric moisture content (at least in the
range 0.18-0.28).  It is approximately equal to the product of the volumetric
moisture content and the molecular diffusivity of KC1 in water.  The practical
implications of the work for field problems are. explored, use being made of
scaling theory for flow processes involving capillarity and viscous flow.  It is
concluded that, for the majority of field soils, solute transport during unsat-
urated flow of any practical duration may be described by a velocity-independent
dispersion coefficient.  This represents a very great simplification of the
formulation, analysis, and prediction of solute transport in such systems.  The
observed pistonlike displacement of the initial water in the columns by the
absorbed wat^er suggests that there is no basis for subdividing the water in the
system into mobile and immobile fractions.  Further theoretical and experimental
work is under way on solute transport during infiltration, and during absorption
into very coarse-textured soils (for which the dispersion coefficient is not
velocity independent.)


78:02G-044
STEADY INFILTRATION FROM SINGLE AND PERIODIC STRIP SOURCES,
Batu, V.
Karadeniz Technical University, Trabson, Turkey, Department of Civil Engineering.
Soil Science Society of America Journal, Vol. 42, No. 4, p 544-549, July-August,
1978.  7 fig, 15 ref, 49 equ.
                                      42

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Descriptors:  Infiltration, Soil water, Fourier analysis, Hydraulic conductivity.
Sprinkler irrigation.

The matric flux potential and horizontal and vertical flux distributions were
obtained using Fourier analysis techniques for single and periodic strip sources
located on the soil surface.  The theory is based on the assumption that the
hydraulic conductivity is an exponential function of the soil water potential.
The matric flux potential distributions were compared with the results obtained
by Warrick and Lomen  (1976, Soil Sci. Soc. Am. J. 40:639-643) who used different
mathematical techniques.


78:02G-045
TRANSIENT CHANGES IN THE SOIL-WATER SYSTEM FROM IRRIGATION WITH SALINE WATER-
I.  THEORY,
Jury, W.A., Frenkel, H., and Stolzy, L.H.
California University, Riverside, Department of Soil and Environmental Science.
Soil Science Society of America Journal, Vol. 42, No. 4, p 579-585, July-August
1978.  5 fig, 5 tab, 15 ref, 11 equ.

Descriptors:  Saline water, Soil water movement, Chemical precipitation.
Leaching, Diffusion, Travel time, Cation exchange, Dispersion, Irrigation water.

Transient soil solution concentrations and salt precipitation rates in the root
zone are shown to be influenced by the ion composition and concentration of the
applied water and soil exchange complex as well as by the water uptake distri-
bution and infiltration rate.  Calculations are performed on three kinds of
infiltration water to estimate the ionic composition of the soil solution, the
rate of gypsum and CaCO3 precipitation, and the time to reach steady state for a
given irrigation management.  Solution concentrations adjusted for exchange
interactions were shown to precipitate twice the quantity of salt in a given
time, resulting in lowered solution concentration and altered composition
Ca(2+), Mg(2+), Na(2+), and S04(2-) ion concentrations in the solution phase,
with up to 1,600 days required to reach steady state through the top 150 cm for
a leaching fraction of 0.05.  The extent of precipitation is also found to
depend strongly on the concentration of sulfate and degree of saturation with
gypsum in the irrigation water.  Diffusion and dispersion are also shown to
influence the duration of the transient phase.


78:02G-046
TRANSIENT CHANGES IN THE SOIL-WATER SYSTEM FROM IRRIGATION WITH SALINE WATER:
II.  ANALYSIS OF EXPERIMENTAL DATA,
Jury, W.A., Frenkel, H., Devitt, D., and Stolzy, L.H.
California University, Riverside, Department of Soil and Environmental Science.
Soil Science Society of America Journal, Vol. 42, No. 4, p 585-590, July-August,
1978.  4 fig, 7 tab, 13 ref, 3 equ.

Descriptors:  Saline water, Soil water movement, Cation exchange, Chemical
precipitation, Solutes, Irrigation water, Wheat, Sorghum, Lysimeters.

Twenty-three lysimeters containing four soil types with alternate wheat (Triticum
aestivum L.) and sorghum (Sorghum vulgare Pers.) crops were irrigated with three
synthesized levels (2.2, 3.9, 7.1 mmho/cm) of"irrigation water.  Salt balance was
calculated from soil salinity sensor electrical conductivity EC measurements by
determining a relationship between solution EC and solution concentration using a
chemical equilibrium model.  Exchangeable cations were measured after the third
crop.  All methods of determining salt balance showed the order of 50% salt
precipitation over the first 500 days of the experiment, approximately two times
the expected amount when root zone salt concentrations have reached steady state.
Release of Ca(2+) ions from exchange sites and subsequent enhanced gypsum and
Ca CO3 precipitation was assumed to be responsible for the difference between
transient and steady-state behavior.  The drainage composition of a lysimeter
which had moved one pore volume through the root zone showed that only Cl(-) was
approaching a steady-state value.  Exchange effects and enhanced precipitation
were assumed to be buffering the concentration of the other ions.  Water uptake
in all lysimeters was occurring primarily in the top 20 cm, a consequence of high
irrigation water salinity and daily irrigation.
                                      43

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78:02G-047
MOISTURE PROFILES DURING STEADY VERTICAL FLOWS IN SWELLING SOILS,
Giraldez, J.V., and Sposito, G.
California University, Riverside, Department of Soil and Environmental Sciences.
Water Resources Research, Vol. 14, No. 2, p 314-318, April, 1978.  3 fig, 1 tab,
21 ref, 10 equ.

Descriptors:  Steady flows, Soil water movement, Saturated flow, Unsaturated
flow, Profiles, Overburden.

Practical working equations for describing numerically soil moisture profiles in
homogeneous swelling soils during steady vertical flows were developed.  These
equations were solved on a computer with soil water and swelling curve data
appropriate to Rideau clay loam, which was taken as a typical example of a
swelling soil.  Unsaturated swelling soils were shown to exhibit either xeric
or hydric profiles for downward flows, whereas for upward flows they exhibit
only a zeric profile, just as rigid soils do.  On the other hand, saturated
swelling soils were shown to have hydric profiles in the downward flow situation
and either hydric or zeric profiles during upward•flows.  The overburden or
"envelope pressure"  potential was shown to exert a great influence, in almost
all circumstances, in reducing the maximum evaporative flow from a shallow water
table in a swelling soil as compared to the equivalent nonswelling case.


78:020-048
A TWO-DIMENSIONAL LINEARIZED VIEW OF ONE-DIMENSIONAL UNSATURATED-SATURATED FLOW,
Cushman, J., and Kirkham, D.
Iowa State University; Ames, Department of Agronomy.
Water Resources Research, Vol. 14, No. 2, p 319-323, April, 1978.  4 fig, 16 ref.

Descriptors:  *Saturated flow, *Unsaturated flow, *Mathematical models, *Numer-
ical analysis, Equations, Finite element analysis,  Infiltration, Moisture con-
tent, Pressure head, Theoretical analysis.

A numerical analysis of the one-dimensional, unsaturated-saturated flow problem
was presented.  Both the pressure head and moisture- content equations were
studied for vertical and horizontal infiltration, respectively.  The problems
were considered in a two-dimensional setting in which time was considered the
second dimension.  The numerical scheme used was finite element analysis
coupled with a simple linearizing assumption.  The numerical process was com-
pared with various other analytic and numerical solutions of the same problems.
It was shown that if the size of the elements is not too large, the method is
very accurate.


78:02G-049
ON OSCILLATION OF NUMERICAL SOLUTION OF A MODIFIED RICHARDS' EQUATION,
Krishnamurthi, N., Sunada, O.K.,. and Longenbaugh, R.A.
Utah International Incorporated, San Francisco, California, Department of
Environmental Quality.
Water Resources Research, Vol. 14, No. 1, p 52-54,  February, 1978.  1 fig,
16 ref, 8 equ.
                *
Descriptors:  Mathematical studies, Numerical analysis, Soil water movement,
Hydraulic conductivity, Gravitational water, Diffusivity.

Numerical solutions of differential equations should be checked for the condi-
tions of consistency, convergence, and stability.  The implicit solutions that
satisfy these conditions are sometimes found to be oscillatory about the true
solutions.  The reasons for these oscillations are explained.  A method to derive
criteria for nonoscillatory solutions of a nonlinear partial differential equa-
tion is outlined.  These criteria for modified Richards' equation are presented,
and their physical significances are explained.


78:02G-050
DENITRIFICATION IN FOUR CALIFORNIA SOILS:  EFFECT OF SOIL PROFILE
CHARACTERISTICS,
                                      44

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Gilliam, J.W., Dasberg, S., Lund, L.J., and Focht, D.D.
California University, Riverside, Department of Soil Science and Agricultural
Engineering.
Soil Science Society of America Journal, Vol. 42, No. 1, p 61-66, January-February,
1978.  4 fig, 3 tab, 25 ref.

Descriptors:  Denitrification, Soil profiles, Steady flow, Soil water movement,
Nitrates, California.

The effects of soil profile characteristics upon rate and products of denitrifica-
tion were investigated using four soils in laboratory columns under steady-state
water flow conditions.  Soils with heavy textured subsoils readily reduced added
N03(-).  However, the soil with the lowest clay content had restricted water flow
in the surface horizon and reduced the greatest amount of N03(-).  It was con-
cluded that any soil condition which impedes water flow will be positively related
to denitrification and that spatial variability in denitrification is likely to be
as great as observed variability in water movement.  The ratio of N2 to N2O found
during denitrification was extremely variable with measured values from 100:1 to
1:4.-  The low concentrations of N20 measured during denitrification occurred in
soils where the denitrification was occurring deep in the soil profile, but there
was no indication that this low concentration was a result of further reduction of
N20 as N2O diffused through the soil profile.  Our data indicate that it is
currently not possible to accurately predict relative amounts of N2 and N2O which
will be produced during most denitrification in soils, and that estimates of that
N2O produced from agricultural lands have a large uncertainty factor.


78:02G-051
RESIDUAL FERTILIZER NITROGEN IN A FLOODED RICE SOIL,
Reddy, K.R., and Patrick, W.H., Jr.
North Carolina State University, Raleigh, Department of Biological and
Agricultural Engineering.
Soil Science Society of America Journal, Vol. 42, No. 2, p 316-318, March-April,
1978.  2'fig, 4 tab, 2 ref.

Descriptors:  Nitrogen, Stable isotopes, Fertilization, Rice, Flood irrigation,
Incubation, Nutrients.

Residual effects of 15N-labelled fertilizer (ammonium sulfate)  nitrogen were
measured during the second cropping season of rice (Oryza sativa L.).  During the
first cropping season, labelled fertilizer N was applied at 100 kg N/ha using
different methods of N application.  At the end of harvest the rice straw obtained
during the first cropping season was incorporated back into the respective plots.
During the second season half the plots were treated with an additional 100 kg N/ha
of nonlabelled fertilizer N as an early season top dressing.  The uptake of residual
labelled N was measured during the growing season and at harvest time under ferti-
lized and nonfertilized conditions.  The recovery of residual labelled N in grain
and straw was 2.7 to 3.1 kg N/ha, with a large fraction of N still remaining in
the soil.  Approximately 3 to 5 kg of the residual labelled N/ha present at the
beginning of the season was not accounted for in any fraction and was assumed to be
lost from the system.  Over a 2-year period, about 66 to 82% of the applied
labelled fertilizer N could be accounted for by plant uptake or in the soil with
the remainder lost from the plant-soil system.


78:02G-052
INFILTRATION DURING AN UNSTEADY RAIN,
Chu, S.T.
South Dakota State University, Brookings, Department of Agricultural Engineering.
Water Resources Research, Vol. 14, No. 3, p 461-466, June, 1978.  1 fig, 3 tab,
12 ref.               ,

Descriptors:  "-Infiltration, *Rainfall,  *Model studies, Mathematical models,
Precipitation (atmospheric), Soil water, Soil water movement, Rainfall intensity,
Precipitation excess, Ponding, Soil moisture, Runoff, Unsteady rain.

Infiltration during a rainfall event can be divided into two distinct stages-  a
stage with surface ponding and a stage without surface ponding.  Few of the infil-
tration models in current use are suitable to describe infiltration for both
stages.  In this paper the Green and Ampt equation was applied to determine the
time that separates these two stages so that infiltration for the different stages
                                        45

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can be  treated  separately.  To obtain an  integrated  form of  the Green and Ampt
equation,  it  is traditionally assumed that  the  cumulative  infiltration  is zero
at the  time when surface ponding starts.  But in a rainfall  event, the  cumulative
infiltration  equals  the water infiltrated into  the soil profile prior to the
ponding time, which  is usually not  zero.  Therefore, a modification in  the tradi-
tional  Green  and Ampt equation is needed  to describe infiltration during a rainfall
event.   It was  shown that this modification is  equivalent  to a shift of the time
scale by an amount which was referred to  as the pseudotime.  The modified version
of the  Green  and Ampt equation was  applied  to determine rainfall excess and to
predict total runoff for three major storms recorded by the  Agricultural Research
Service from  1957 to 1959 on a watershed  near Oxford, Mississippi.  A comparison
of the  prediction and the measured  total  runoff appeared to  be promising.


78:02G-053
THE STATISTICAL MECHANICAL THEORY OF WATER  TRANSPORT THROUGH UNSATURATED SOIL 1.
THE CONSERVATION LAWS,
Sposito, G.
California University, Riverside, Department of Soil and Environmental Sciences.
Water Resources  Research, Vol. 14,  No. 3, p 474-478, June, 1978.  26 ref, 30 equ.

Descriptors:  Soil water movement,  Unsaturated  flow. Momentum equation, Fluid
mechanics, Continuity equation, Heterogeneity,  Soil physics.

The macroscopic  differential equations of mass  and momentum  balance for water in
a rigid unsaturated  soil are derived from first principles by using the methods
of statistical mechanics.  The derivation begins with the development, at the
molecular  level,  of  expressions for the mass and linear momentum densities of water
in a soil.  The  derivatives of these expressions with respect to the time then
provide for local balance equations that are ensemble averaged and local volume
averaged in order to produce the macroscopic balance equations.  The resulting
macroscopic equations agree with those derived  for mass and  linear momentum transport
in a soil on  the basis of the continuum theory  of mixtures.  The unified insight
into mass  transport  processes afforded by a statistical mechanical theory as com-
pared to one  evolved from a solely  macroscopic  view is discussed.


78:02G-054
THE STATISTICAL  MECHANICAL THEORY OF WATER  TRANSPORT THROUGH UNSATURATED SOIL 2.
DERIVATION OF THE BUCKINGHAM-DARCY  FLUX LAW,
Sposito, G.
California University, Riverside, Department of Soil and Environmental Sciences.
Water Resources  Research, Vol. 14, No. 3, p 479-484, June, 1978.  18 ref, 55 equ.

Descriptors:  Soil water movement,  Unsaturated  flow, Soil water, Hydraulic
conductivity. Steady flow, Model studies, Markov processes.  Soil physics.

The Buckingham-Darcy flux law, an empirical equation that relates the volumetric
flux density of water in an unsaturated soil to the gradient of the total potential,
is derived from  first principles by using the methods of statistical mechanics.   The
derivation given, a direct application of well-known techniques in nonequilibrium
statistical mechanics, proceeds through a detailed molecular description of two
laboratory experiments for measuring the hydraulic conductivity tensor of a homo-
geneous  unsaturated soil.  In the first experiment the steady flow of water is
induced by a gradient in the matrie potential, while in the  second, flow is induced
by a gradient in  the gravitational potential.    In both cases, the appropriate
form of  the BUckingham-Darcy law is derived on  the basis of  a linear response
approximation, and an expression for the hydraulic conductivity is given in terms
of a time integral of the correlation function  for the velocities of the water
molecules in the  soil.   The problem of calculating the hydraulic conductivity of
a soil  thereby is reduced to quadrature and to  the task of developing a molecular
model of the velocity correlations among the water molecules.  A recent successful
model of this type is discussed briefly.


78:02G-055
A PARAMETER-EFFICIENT HYDROLOGIC INFILTRATION MODEL,
Smith, R.E., and  Parlange, J.Y.
Agricultural Research Service, Fort Collins, Colorado.


                                       46

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Water Resources Research, Vol. 14, No. 3, p 533-538, June, 1978.  6 fig, 18 ref.

Descriptors:  *Infiltration, *Ponding, *Model studies, Mathematical models,
Rainfall, Hydraulic conductivity, Soil water, Soil water movement. Soils, Soil
types, Equations, Infiltration rates, Hydrology, Infiltration models.

By adopting two extreme assumptions concerning the behavior of unsaturated soil
hydraulic conductivity K near saturation, a two-branched model was derived for
ponding time and infiltration rate decay for arbitrary rainfall rates.  One
assumption was that K varies slowly near saturation and leads to an expression
for ponding time and infiltration decay.  For initially ponded conditions, ponding
time was zero, and with the rainfall rate approaching infinity, the familiar
Green and Ampt expression results.  The other, rather opposite assumption was that
K varies rapidly, e.g., exponentially, near saturation.  This model also holds for
both rainfall_and ponded surface conditions, and for ponded conditions the expres-
sion is identical to that of Parlange.  Each model uses only two parameters,
saturated soil conductivity K sub s and a parameter that is roughly related to
sorptivity and responds nearly linearly to variations in initial saturation.
Both parameters are physically related to measurable soil properties.  Methods
were presented to estimate parameters of either model from infiltrometer tests.
The two models were compared with a precise numerical solution of the unsaturated
soil water diffusion equations for three soils that represent a range of soil
behaviors near saturation.  Results showed that either assumption would be an
excellent model for most hydrologic purposes, and the relative goodness of fit
of each model is generally consistent with the appropriate behavior of K, as the
water content approaches the saturated water content.


78:02G-056
BASIC MATHEMATICAL MODELS OF TOXICANT TRANSPORT THROUGH THE SOIL PROFILE,
Rachinskii, V.V.
Timiryazev1 Academy of Agricultural Sciences, Moscow, Union of Soviet Socialist
Republics.
In:  Symposium on Environmental Transport and Transformation of Pesticides,
October, 1976, Tbilis, USSR.  EPA-600/9-78-003, February, 1978. Athens, Georgia,
p 201-209.  5 ref, 26 equ.

Descriptors:  Pesticide kinetics, Sorption, Dynamics, Mathematical models,
Chromatography, Kinetics, Pesticide toxicity.

This paper discusses basic mathematical models of toxicant transport through
the soil profile; and has developed mathematical expressions for the sOrption
dynamics problems using the kinetic parameter of time lag'and at a variable
velocity of the mobile phase.


78:02G-057
DRAINAGE IN A NATURAL LAYERED PROFILE BY FINITE ELEMENT ANALYSIS,
Khanjani, M.J., and Bloomsburg, G.L.
Idaho University, Moscow, Department of Agricultural Engineering.
Paper No. 78-2036, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 18 p.  8 fig, 1 tab,
5 ref.

Descriptors:  Drainage, Finite element analysis, Computer programs, Subsurface
drains. Water table, Porosity, Hydraulic conductivity, Soil properties, Soil
profiles, Pore pressure.

An agricultural soil profile consisting of four different soil types is modeled
by means of a finite element computer program.  The results are in the form of
a curve for water table height at midpoint between drains versus a dimensionless
function of time.  Composite values for soil properties (apparent, conductivity,
displacement head, and drainage porosity)  are calculated, and the result from
running a one layer composite profile are compared to results from an actual
profile.  The effect of drain distance above the impermeable layer is also
investigated.  The Dupuit-Forchheimer assumptions are not used in this analysis
and unsaturated flow above the water table is considered.
                                       47

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 78:02G-058
 INFLUENCE OF SOIL AIR AND DRAINAGE ON INFILTRATION,
 Jarrett, A.R., Hoover, J.R., and Davis, C.L.
 Pennsylvania State University, University Park, Department of Agricultural
 Engineering.
 Paper No. 78-2039, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 8 p.  7 fig, 22 ref.

 Descriptors:  Infiltration, Infiltration rates, Drainage, Air, Subsurface drainage,
 Rainfall, Runoff, Subsurface drains, Surface runoff, Laboratory tests.

 The effect of soil air entrapment and subsurface drainage in a sand were evaluated.
 During rainfall, the entrapped soil air pressure stopped the infiltration process
 converting all precipitation to runoff except when the entrapped air was permitted
 to vent via the subsurface drain, at which time infiltration and subsurface drainage
 started and runoff ceased.


 78:020-059
 A SIMPLE FINITE ELEMENT METHOD OF INFILTRATION,
 Pall, R., Jarrett, A.R., and Morrow, C.T.
 Pennsylvania State University, University Park, Department of Agricultural
 Engineering.
 Paper No. 78-2068, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 10 p.  14 fig, 12 ref,
 8 equ.

 Descriptors:  Infiltration, Infiltration rates. Soil water movement, Numerical
 analysis, Finite element analysis, Darcy's law, Diffusivity, Computer models,
 Energy conservation, Soil water.

A numerical solution of one dimensional infiltration was developed from basic
 principles of flow and energy conservation using finite element technique.  An
 exponential relationship between hydraulic diffusivity and volumetric moisture
 content was used for diffusivity calculations.  Solutions obtained for horizontal
moisture distribution gave an excellent agreement with exact solution of Scott
 et al. and numerical solutions of Philip and Hanks 'and Bowers.


 78.-02G-060
PREDICTING DISPERSION COEFFICIENTS IN SOILS,
Smajstrla, A.G., Reddell, D.L., and Barnes, P.L.
Texas A & M University, College Station, Department of Agricultural Engineering.
Paper No. 78-2074, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 16 p.  16 fig, 18 ref,
 10 equ.

Descriptors:  Dispersion, Soil physical properties, Numerical analysis, Hydrologic
properties,  Soil water movement,' Capillary water,  Diffusion, Simulation analysis,
Model studies,  Computer models.

A numerical model was developed to predict the magnitudes of dispersion coefficients
as functions of soil physical and hydrologic properties and solution velocities.
A capillary bundle model was used, and the bundle  hydraulic properties were deter-
mined from the hydraulic conductivity function.  Interaction between bundles was
described as a diffusion-controlled process.  The  model'generated breakthrough
curves from simulated steady flow displacement of  one soil solution with a second
one.   From the breakthrough curves,  dispersion coefficients were calculated.  The
breakthrough curves and dispersion coefficients were compared with those measured
 in the laboratory with good agreement for unsaturated flow conditions and for
saturated flow at low velocities.  Agreement during saturated flow at large veloci-
 ties was only obtained when a matching factor was  used to describe mixing between
capillary bundles.
                                        48

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78:02G-061
TRANSIENT FLOW IN UNSATURATED POROUS MEDIA,
Lin, S.H.
Polytechnic Institute of New York, Brooklyn, Department of Chemical Engineering.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY7, Proceedings Paper 13886, p 975-982, July, 1978.  4 fig, 12 ref.

Descriptors:  *Porous media, *Unsaturated flow,,*Diffusion, Hydraulic conductivity,
Infiltration, Moisture content, Unsteady flow, Silts, Loam, Soil water movement,
Mathematical models, Equations, Orthogonality.

Transient water movement in both horizontal and vertical unsaturated porous media
was investigated.  The nonlinear partial differential equation governing the one-
dimensional flow was solved by the orthogonal collocation method.  This method
involves the approximation of the spatial derivative terms in the partial differen-
tial equation by an orthogonal polynomial and thus the partial differential
equation is transformed into a set of ordinary differential equations which in
turn-can be integrated numerically.  The present numerical solutions were found
to be in excellent agreement with previous solutions for the cases under considera-
tion.  Because of its high accuracy, computational stability, and easy implemen-
tation, the orthogonal collocation method can be a very good alternative for
tackling these nonlinear diffusion problems.


78:02G-062
LONGITUDINAL AND TRANSVERSE DISPERSION COEFFICIENTS IN UNSATURATED PLAINFIELD
SAND,
Yule, D.P., and Gardner, W.R.
Wisconsin University, Madison, Department of Soil Science.
Water Resources Research, Vol. 14, No. 4, p 582-588, August, 1978.  7 fig, 2 tab,
19 ref.

Descriptors:  *Dispersion, *Soils, *Sands, *Laboratory tests. Instrumentation,
Mathematical models, Soil water movement, Unsaturated flow, Transverse dispersion,
Longitudinal dispersion.

The relationship between the longitudinal and transverse dispersion coefficients
(D sub L and D sub T) and the pore water velocity  (v) and the effective diffusion
coefficient  (D sub e) was determined for v between 0.01 and 0.28 cm/min in a
vertical unsaturated column  (L =  23 cm) of C horizon Plainfield sand.  The inflow
and outflow control systems on the soil column consisted of rows of porous ceramic
tubes with individual adjustable  pressure controls.  Uniform inflow and outflow
were achieved across the column,  and v was maintained constant during each
experiment.  An analysis of the transverse spread produced indicated that the
effect of apparatus-induced dispersion was less than 10%.  D sub L  (sq cm/min) was
linearly related to v(cm/min)  (D  sub L = 0.216v + 0.0032; sq r = 0.90).  Slightly
larger D sub L was found in experiments with H2O replacing Cl than in experiments
with Cl replacing H2O.  D sub L at the lowest v was 2 orders of magnitude greater
than D sub e.  D sub T  (sq cm/min) was essentially independent of v(d sub T =
0.0035V + 0.0031; sq r = 0.15) and was about 2 orders of magnitude greater than
D sub e at the lowest v studied.  The spread of tracer at the outflow was inversely
proportional to v, and transverse dispersion had reduced the concentration peak of
the inflow by 84% at L = 23 cm and v = 0.01 cm/min.  The ratio D sub L/D sub T
was proportional to v and ranged  from about l(v = 0.01 cm/min) to about 20  (v =
0.28 cm/min).


78:02G-063
ANALYSIS OF A CAPILLARY HYSTERESIS MODEL BASED ON A ONE-VARIABLE DISTRIBUTION
FUNCTION,
Mualem, Y., and Morel-Seytoux, H.J.
Colorado State University, Fort Collins, Engineering Research Center.
Water-Resources Research, Vol. 14, No. 4, p 605-610, August, 1978.  11 fig, 12 ref.

Descriptors:  *Hysteresis,  *Soil  moisture,  *Model studies, *Mathematical models,
*Theoretical analysis, Porous media, Soil water movement, Model calibration,
Drying curves, Soil science.
                                       49

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 Parlange's  model corresponds to a special case of Mualem's similarity hypothesis
 f(psi sub w,  psi sub d)  = h(psi sub w)l(psi sub d)  in which h(psi)  is set at
 unity for all psi values.  Interpreted in terms of the soil water domain theory,
 this assumption implies  that the relative pore volume of  the domains  is  distributed
 uniformly in  respect to  the wetting radius (or to psi sub  w).   In this paper,  the
 proper mathematical  equation was derived for calibrating  the model from  the
 experimental  main drying curve.  The applicability of Parlange's model for the
 soil water  hysteresis was analyzed theoretically and extensively tested  for
 different types of porous media.  Theoretical hysteretic  curves  derived  by
 direct implementation of Parlange's model were compared with experiments.  These
 comparisons showed that  Parlange's model contradicts well-known  properties of the
 soil moisture characteristics.   The good results reported by Parlange were not
 obtained  when actual measured curves of the hysteresis loop were used.   Whether
 the  main  branch of hysteresis for wetting or for drying is used  in calibration,
 badly distorted shapes of hysteresis curves are obtained.   Parlange's suggestion
 for  calibrating the  model on the basis of the main drying curve  plus  on6 addi-
 tional point  from the main wetting curve is considered too arbitrary  to  be
 reliable.


 78:02G-064
 A MATHEMATICAL TREATMENT OF INFILTRATION FROM A LINE SOURCE  INTO AN INCLINED
 POROUS MEDIUM,
 Zachmann, D.W.
 Colorado  State University,  Fort Collins,  Department of Mathematics.
 Soil Science  Society of  America Journal,  Vol.  42,  No.  5,  p 685-688, September-
 October,  1978.   3  fig, 1 tab, 15 ref,  31 equ.

 Descriptors:   Infiltration,  Mathematical studies,  Porous  media,  Hydraulic
 conductivity,  Pressure head.  Capillary action.  Steady  flow.

 An exact  mathematical  solution  was  obtained for  two-dimensional  steady infiltration
 from a line source into  an inclined porous  medium with an  impermeable lower
 boundary.   Unsaturated hydraulic conductivity was  assumed  to be  an  exponential
 function  of pressure head.   Equations  for  a stream function and  the pressure  head
 were developed and stream lines  and contours of  constant pressure head were plotted
 for  a sandy soil and a clay  soil using inclinations  of 5 degrees  and  20  degrees
 from horizontal.


 78:02G-065
 SOLUTE TRAVEL-TIME ESTIMATES FOR TILE-DRAINED FIELDS:   III.  REMOVAL  OF  A
 GEOTHERMAL BRINE SPILL FROM  SOIL BY LEACHING,
 Jury,  W.A.,  and Weeks, L.V.
 California University, Riverside, Department of  Soil and Environmental Sciences.
 Soil  Science  Society of America  Journal, Vol. 42, No.  5, p 679-684, September-
 October,  1978.  7 fig, 3  tab, 10  ref,  13 equ.

 Descriptors:   Ion exchange, Solutes, Travel time, Estimating, Brines,  Leaching,
 Reclamation,  Tile drainage, Ion  transport,  Soil water movement.

 The  time required to leach a slug of saline, sodic geothermal brine from the
 point  of injection to  the  tile outlet  of an artificially drained field was          ;
 calculated.    Sprinkler, complete, and  partial ponding  leaching methods were com-
 pared  as a function of drain spacing and initial  location of the spill.  Calculated
 results were  presented as dimensionless parameters which scale the drainage system
 dimensions and the soil water transport properties.  Ponded leaching required
more water,  but less time to leach brine out of  the system for all situations
 except where  the brine spill occurs near the midpoint between tile lines.  A
 simple calculation was proposed  to  estimate the leaching fluid volume  required
 to remove excess Na(+) from the  exchange complex.  Good agreement was  attained
between simulated and experimental results  involving a laboratory s"oil column.
 It was estimated that for fine-textured soils in the Imperial Valley of California
 it may require up to 30 pore volumes of leaching fluid to replace Na(+) with
Ca(2+) if saturated gypsum solution is used in reclamation.  Application time
per pore volume was calculated to be in excess of 1 year for all cases except
ponded leaching directly over a tile line.
                                      50

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78:02G-066
DISPLACEMENT OF SOIL WATER BY SIMULATED RAINFALL,
Quisenberry, V.L., and Phillips, R.E.
Clemson University, South Carolina, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 5, p 675-679, September-
October, 1978.  3 fig, 3 tab, 15 ref, 1 equ.

Descriptors:  Soil water movement, Simulated rainfall, Tracers, Soil water,
Moisture content, Laboratory tests.

Displacement of initial soil water by simulated rainfall was measured in
aggregates of Maury silt loam soil in columns in the laboratory and under field
conditions using tritiated water and/or Cl- as a tracer of added water.  Dis-
placement values measured in aggregates were larger  (53 to 85%) than those
measured under field conditions (7 to 56%).  Percent displacement of initial
soil water in Galloway silt loam under field conditions were similar to those
of Maury, but were larger in Huntington silty clay loam than in Maury.  Initial
soil water content of Maury soil did not appear to affect percent displacement.
Percent displacement in Maury soil increased as the depth of tillage increased.


78:02G-067
THE DEPENDENCE OF THE PARAMETERS IN THE GREEN AND AMPT INFILTRATION EQUATION ON
THE INITIAL WATER CONTENT IN DRAINING AND WETTING STATES,
Aggelides, S., and Youngs, E.G.
Cambridge University, Cambridge, England, Department of Applied Biology.
Water Resources Research, Vol. 14, No. 5, p 857-862, October, 1978.  10 fig,
1 tab, 22 ref, 18 equ.

Descriptors:  Infiltration, Infiltration rates, Moisture content, Soil water
movement. Drying, Wetting, Hysteresis.

The parameters in the Green and Ampt infiltration equation were determined from
infiltration experiments in a sand column at various uniform initial water contents
in both draining and wetting states and were compared with various estimate ob-
tained from the soil water properties measured on the same experimental column.
The estimates of the soil water pressure head at the wetting front were generally
more negative than the values obtained from the directly measured parameters.
It was found that the calculated cumulative infiltration as a function of time
was fitted better by using Bouwer's crude "water entry" estimate than values
deduced by approximating Richards' flow equation.


78:02G-068
CLIMATE, SOIL, AND VEGETATION 3.  A SIMPLIFIED MODEL OF SOIL MOISTURE MOVEMENT
IN THE LIQUID PHASE,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 722-730, October, 1978.  13 fig,
15 ref, 62 equ.

Descriptors:  Soil water movement, Mathematical models, Porous media, Water
balance, Infiltration, Capillary action, Analytical techniques, Climatic data,
Soil properties. Vegetation.

Natural soil systems were modele'd one dimensionally from the surface to a
stationary water table by a homogeneous medium defined by three independent para-
meters.  Four varieties of soil moisture movement were analyzed separately, and
their effects were linearly superimposed.  Infiltration and exfiltration were des-
cribed by the Philip equation, which assumed the.medium to be effectively semi-
infinite and the internal soil moisture at the beginning of each storm and inter-
storm period was assumed to be uniform at its long-term space-time average.  The
exfiltration equation was modified for the presence of natural vegetation through
the approximate introduction of a distributed sink representing the moisture
extraction by plant roots.  Gravitational percolation to groundwater was assumed
to be steady throughout the rainy season at a rate determined by the long-term
space-time average soil moisture.  Capillary rise from the water table was assumed
to be steady throughout the year and to take place to a dry surface.
                                      51

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 78:020-069
 CLIMATE,  SOIL,  AND VEGETATION  6.  DYNAMICS OF  THE ANNUAL WATER BALANCE,
 Eagleson, P.S.
 Massachusetts  Institute of  Technology,  Cambridge, Department of Civil Engineering.
 Water  Resources Research, Vol.  14, No.  5, p  749-764, October, 1978.  11  fig,
 4  tab,  20 ref,  74 equ.
 (See 78:02A-008)


 78:02G-070
 CLIMATE,  SOIL,  AND VEGETATION  7.  A DERIVED  DISTRIBUTION OF ANNUAL WATER YIELD,
 Eagleson, P.S.
 Massachusetts  Institute of  Technology,  Cambridge, Department of Civil Engineering.
 Water  Resources Research, Vol.  14, No.  5, p  765-776, October, 1978.  10  fig,
 3  tab,  13 ref,  35 equ.
 (See 78:02A-007)


 78:02G-071
 A  TWO-ELEMENT  CERAMIC SENSOR FOR MATRIC POTENTIAL AND SALINITY MEASUREMENTS,
 Scholl, D.G.
 Forest  Service,  United States  Department of  Agriculture, Albuquerque, New Mexico,
 Rocky Mountain  Forest and Range Experimental Station.
 Soil Science Society of America Journal, Vol.  42, No. 3, p 429-432, May-June,
 1978.   3  fig,  6 ref.

 Descriptors:   *Soil moisture meters, *Saline soils, *Salinity, *Soil moisture,
 *Salinity sensor, *Soil moisture sensor, *Coalmine spoil, *Salinity meter,
 *Matric potential sensors,  Salinity measurements.

 A  two-element  ceramic sensor was developed to  produce optimum electrical response
 to both soil water matric potential and salinity.  A spring-loaded housing was
 developed for  the elements  for either drill-hole or pit-face placement.  The
 sensors were calibrated under various matric potential, salinity, and temperature
 conditions.  An initial field test with 72 sensors was conducted under irrigated
 coal mine spoil conditions.  Laboratory and  field results indicated reasonable
 instrument precision over a wide range of matric potential and salinity.  The
 correlation between sensor output and water  content in the field was best where
 the mean of several sensors was used.


 78:020-072
 DERIVATION OF EQUATIONS FOR VARIABLE RAINFALL  INFILTRATION,
 Morel-Seytoux,  H.J.
 Colorado State  University, Fort Collins, Engineering Research Center.
Water Resources  Research, .Vol. 14, No.  4, p  561-568, August, 1978.  7 fig, 2 tab,
 9  ref,  41 equ,  1 append.

 Descriptors:  Infiltration, Infiltration rates, Rainfall, Ponding, Estimating
 equations. Soil water movement, Mathematical models.

 Formulae were derived for prediction of ponding time and cumulative infiltration
 following ponding under a condition of piecewise variable and even intermittent
 rainfall.  The  derivatives do not assume immediate saturation at the surface or
 a  piston displacement of air by water; they  include the viscous flow of air.  The
 results were compared with experimental data of James and Larson (ASAE Winter
Meeting Paper,  Chicago, Illinois, 1974) for  two conditions:  constant rainfall
and intermittent rainfall.  The proposed formulae are simple to use, requiring
no complex solution of a partial or even an  ordinary differential equation.  The
numerical calculations presented in the paper were performed with a small pocket
calculator.   The agreement with experimental data is good.


 78:02G-073
EMPIRICAL EQUATIONS FOR SOME SOIL HYDRAULIC PROPERTIES,
Clapp,  R.B., and Hornberger, G.M.
Virginia University, Charlottesville, Department of Environmental Sciences.
Water Resources Research, Vol. 14, No. 4, p  601-604, August, 1978.  2 fig, 2 tab,
15 ref, 7 equ.


                                      52

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Descriptors:  Soil physical properties,  Hydraulic properties.  Soil moisture,
Hydraulic conductivity, Infiltration,  Air entrainment,  Moisture tension,  Equations.

The soil moisture characteristic may be modeled as a power curve combined with a
short parabolic.section near saturation to represent gradual air entry.  This
two-part function—together with a power function relating soil moisture  and
hydraulic conductivity—was used to derive a formula for the wetting front suction
required by the Green-Ampt equation.  Representative parameters for the moisture
characteristic, the wetting front suction, and the sorptivity, a parameter in the
infiltration equation derived by Philip (Soil Sci., 84, 257-264, 1957), were
computed by using the desorption data of Holtan et al.  (ARS 41-411, 609 pp.,  ARS,
Beltsville, Maryland, 1968).  Average values of the parameters, and associated
standard deviations were calculated for 11 soil textural classes.  The results
of this study indicate that the exponent of the moisture characteristic power
curve can be predicted reasonably well from soil texture and that gradual air entry
may have a considerable effect on a soil's wetting front suction.


78:02'G-074
CLIMATE, SOIL, AND VEGETATION 1.  INTRODUCTION ,TO WATER BALANCE DYNAMICS,
Eagleson, P.S.
Massachusetts Institute of Technology, Cambridge, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 705-712, October, 1978.  8 fig, 16 ref,
23 equ.

Descriptors:  Water balance, Dynamics, Climatic data, Vegetation, Stochastic
processes, Probability, Soil moisture, Statistical methods, Soil-water-plant
relationships, Soil properties.

A statistical dynamic formulation of the vertical water budget at a land-atmosphere
interface was outlined.  Physically based dynamic and conservation equations
expressed the infiltration, exfiltration, transpiration, percolation to groundwater
and capillary rise from the water table during rainstorms and interstorm periods
in terms of independent variables representing the precipitation, potential evapo-
transpiration, soil and vegetal properties, and water table elevation.  Uncertainty
was introduced into these equations through the probability density function of the
independent climatic variables and yielded derived probability distributions of the
dependent water balance elements:  surface runoff, evapotranspiration, and groundwater
runoff.  The mean values of these quantities gave a long-term average water balance
which, to the first order, defined the annual water yield and water loss in terms
of the annual precipitation and potential evapotranspiration and in terms of physical
parameters of the soil, vegetation, climate, and water table.  This analytical
framework provides physical insight into the dynamic coupling of climate-soil-
vegetation systems.


78:020-075
ERRORS IN GAMMA HRAY MEASUREMENTS OF WATER CONTENT AND BULK DENSITY IN NONUNIFORM
SOILS,
Nofziger, D.L.
Oklahoma State University, Stillwater, Department of Agronomy.
Soil Science Society of America Journal, Vol.  42, No. 6, p 845-850, November-
December, 1978.  7 fig, 1  tab, 6 ref, 7 equ.                                  ,

Descriptors:  Soil moisture, Soil water. Moisture content, Bulk density,  Measurement,
Stratification, Infiltration, Attenuation, Gamma rays, Clays.

Recent experimental study  of freezing soils has shown gamma-ray measurements of
water content and bulk density are  in error when the water content and bulk density
are not uniform throughout the gamma-ray beam.  Many gamma-ray measurements involve
nonuniform  soils.  This study was conducted to determine the magnitude of errors
due to nonuniform bulk density and water content.  Errors in gamma-ray water content
and bulk density were determined for soil-water systems with linear and step-function
changes in water content and bulk density and  for measurements of water absorption
by a nonswelling porous medium.  Both single-energy and dual-energy gamma-ray systems
were analyzed.  The results showed  that large  errors in water content and bulk
density determined by dual-energy gamma-ray measurements can occur for highly
stratified  soils and relatively small errors occur if the bulk density and water
content change linearly in the collimated beam.  Both single- and dual-energy systems


                                        53

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 accurately measured  the  average water content  in  the  collimated beam when the
 bulk  density  of  the  soil was  constant.  However,  the  average water content
 in  the  beam did  not  always  represent the water content at the middle of the
 collimated beam  and  the  middle of  the preset time period.  Errors due to non-
 uniform soil  can be  evaluated using the equations and graphs presented.


 78:02G-076
 SEASONAL WATER USE BY WINTER  WHEAT GROWN UNDER SHALLOW WATER TABLE CONDITIONS,
 Saini,  B.C.,  and Ghildyal,  B.P.
 G.B.  Pant University of  Agriculture and Technology, Pantnagar, Distr. Nainital,
 India.
 Agricultural  Water Management, Vol. 1, No. 3,  p 263-276, November, 1978.  10 fig,
 1 tab,  27 ref.

 Descriptors:  Water  requirements,  Soil water movement, Shallow water, Moisture
 tension, Water management  (applied), Moisture  content, Root zone, Tensiometers,
 Moisture deficit, Wheat.

 Techniques for estimating seasonal water use from soil profile water depletion
 frequently do not account for flux below the root zone.  A method using tensio-
 meters  for obtaining evapotranspiration losses from the root zone and water
 movement below it was discussed.   Soil water flux below the root zone was
 approached by a  sequence of pseudo steady state solutions of the flow equation.
 Upward  soil water flux contributed 36 to 73% to the total water requirement of
 winter  wheat  (Triticum aestivum L.) whereas soil  water depletion accounted for
 11  to 19% only.   Water use  efficiency with one irrigation during an early
 stage of plant development  was greater than with  no or three irrigations.  This
 was the result of both decrease of resistance due to  soil moistening and better
 root  development.  Tensiometer readings were also interpreted to estimate root
 zones,  water  table depths and soil moisture contents.  Methods described in this
 paper can be  used in determining seasonal water use by growing crops, replacing
 or  supplementing  lysimeter  or meteorology approaches  to this problem.


 78:02G-077
 CONVECTIVE TRANSPORT OF  SOLUTES BY STEADY FLOWS 1.  GENERAL THEORY,
 Raats,  P.A.C.
 Institute for Soil Fertility, Oosterweg 92, Haren, The Netherlands.
 Agricultural  Water Management, Vol. 1, No. 3, p 201-218, November, 1978.  3 fig,
 1 tab,  10 ref, 64 equ.

 Descriptors:  Soil water movement, Solutes, Convection, Steady flow, Theoretical
 analysis, Anisotropy, Water quality, Travel time, Leaching, Drainage.

 A comprehensive theory describing  convective transport of solutes was presented.
 The time required for a  parcel of water to move from one point to another along
 a streamline  was  determined,  and this basic information was then used to describe
 collections of parcels of water forming a surface.  Input-output relationships
 were  determined in terms of the distribution of the solute over the inflow and out-
 flow  surfaces.  A simple geometric transformation was used to extend the theory
 to anisotropic media.


 78:02G-078
 CONVECTIVE TRANSPORT OF  SOLUTES BY STEADY FLOWS II.   SPECIFIC FLOW PROBLEMS,
 Raats,  P.A.C.
 Institute for Soil Fertility, Oosterweg 92, Haren, The Netherlands.
 Agricultural Water Management, Vol. 1, No. 3, p 219-232, November, 1978.  5 fig,
 31 ref,   27 equ.

 Descriptors:  Soil water movement, Solutes, Convection, Steady flow, Drainage,
 Leaching, Flow characteristics,  Flow system,  Travel time.

 A comprehensive .theory describing convective transport of solutes was presented
 in Part I (Agric. Water Manage., 1:201-218).   In  this paper,  the general theory
was applied to specific  flow  problems.  The relatively simple problem of leaching
 to drains and ditches induced by an input distributed uniformly over the surface
was discussed in  detail.   It was shown that if the ratio of the halfspacing between
 the drains or ditches and the depth to the impermeable layer is larger than about
 five,  density distribution  is approximately exponential.   The general theory was
 also  used to  evaluate the literature on many other problems.
                                       54

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78:02G-079
SOIL WATER RETENTION AS RELATED TO PARTICLE SIZE IN SELECTED SANDS AND LOAMY
SANDS,
Rivers, E.D., and Shipp, R.F.
Bureau of Reclamation, Bismark, North Dakota, Missouri-Souris Projects Office.
Soil Science, Vol. 126, No. 2, p 94-100, August, 1978.  1 fig, 3 tab, 7 ref.

Descriptors:  *Soil water, *Particle size, *Soil-texture, *North Dakota, *Soil
water retention, *Glacial Lake Souris basin (ND), Retention, Field capacity,
Soils, Loam.

Sands and loamy sand within the Glacial Lake Souris basin in North Dakota vary
considerably Jroni one area to another in their particle size distribution.  The
objective was to relate water retention of these sandy soil textural classes to
particle size percentage.  Water retention percentages, on an over-dry basis,
were determined for samples at field capacity under field conditions and also at
1/10-, 1/15-, and 1/20-bar soil water suction for air-dried, less than 2-mm
samples in conventional porous ceramic plate-pressure pot equipment.  No single
soil water suction produced water retention values adequately representing
field capacity for all textures.  In most instances, the percentage of very fine
sand alone and in combinations with the percentages of silt and clay were corre-
lated significantly with soil water values.


78:02G-080
THE DEPENDENT DOMAIN THEORY APPLIED TO SCANNING CURVES OF ANY ORDER IN HYSTERETIC
SOIL WATER RELATIONSHIPS,
Poulovassilis, A., and El-Ghamry, W.M.
Agricultural Research Council, Cambridge, England, Unit of Soil Physics.
Soil Science, Vol. 126, No. 1, p 1-8, July, 1978.  9 fig, 13 ref.

Descriptors:  *Soil water, *Hysteresis, *Model studies, Mathematical models,
Wetting, Drying, Moisture content, Pressure, Pore pressure, Theoretical analysis.

The dependent domain theory was extended to cover scanning curves of any order
in the hysteretic relationship between soil water content, theta, and pressure,
P.  It was argued that if the distribution function1, F, for the domains depends
on the most recent reversal value of P, than F depends also on all the previous .
reversalt values.  Experimental primary scanning curves and scanning curves of
the first, second, and third orders of the relationship between theta and P for
a sand were presented, and the hysteretic behavior of this experimental relation-
ship was compared with that predicted by the dependent domain theory.


78:02G-081
PREDICTED AND MEASURED DRAINABLE POROSITIES FOR FIELD SOILS,
Skaggs, R.W., Wells,  L.G., and Ghate, S.R.
North  Carolina  State  University, Raleigh,  Department of Biological  and Agricultural
Engineering.
Transactions of  the American  Society of Agricultural Engineering, Vol. 21, No.  3,
p 522-528, May-June,  1978.   8 fig,  3 tab,  12 ref.

Descriptors:  *Porosity,  *Soil properties,  *Drainage, *Model studies, *Drainable
porosities. Laboratory tests, Soil water movement, Water  table, Soil science,
Soils.

Experiments were conducted on large field  cores  to determine the relationship
between drainage volume  and water table depth for five soils.  The  measured
drainage volumes were  less than predicted  from  the soil water characteristics
for three soils,  but were in  good agreement for  the other two.  Drainable poro-
sities were calculated from both theoretical and experimental drainage volume-
water  table depth relationships by assuming that the unsaturated zone is
essentially  "drained  to  equilibrium" with  the water table.  The experimental
drainable porosities  thus obtained were less than predicted.  Drainable porosities
for drainage to  two-dimensions were calculated  from experimental results  for
one dimension by assuming an  elliptical water table profile.  These results gave
nearly constant  drainable porosities for the layered soils  and a variable drainable
porosity for Wagram,  a homogeneous, sandy  soil.
                                        55

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78:020-082
TIME OF SPREAD RELATIONSHIP IN IRRIGATION CHECK BASINS,
Sharma, T.C.
Guelph University, Ontario, Canada.
Transactions of the American Society of Agricultural Engineers, Special Edition,
Vol. 21SW, No. 3, p 505-509, June 20, 1978.  3 fig, 4 tab, 5 ref, 10 equ.

Descriptors:  Basins, Irrigation, Dimensional analysis, Time, Infiltration,
Estimating, Estimating equations.

Time of spread of water in a check basin is of vital importance for designing
efficient check basin irrigation system.  The analytical solutions for determina-
tion of time of spread tend to be quite complex and impractical due to the un-
steady spatially varied nature of flow on nearly zero slopes of the land.  In
this study, the technique of dimensional analysis was used to derive time of
spread relationships in check basins.


78:02G-083
INTAKE CHARACTERISTICS OF IRRIGATION FURROWS.
Fangmeier, D.D., and Ramsey, M.K.
Arizona University, Tucson, Department of Soils, Water and Engineering.
Transactions of the American Society of Agricultural Engineers, Special Edition,
Vol. 21SW, No. 4, p 696-700, 705, August 20, 1978.  3 fig, 3 tab, 5 ref, 19 equ.

Descriptors:  Infiltration, Intakes, Furrow irrigation, Infiltration rates,
Furrows, Estimating equations.

Seven irrigations were conducted on precision field furrows.  Water volume balances
were used to calculate infiltration and intake functions.  The Philip equation
provided a slightly better estimate of infiltration than the Kostiakov equation,
but the constants in the Philip equation were more difficult to obtain.  The
intake rate appeared to be linearly related to the wetted perimeter for the
irrigations conducted.


78:02G-084
VARIABILITY OF SOIL WATER RETENTION CURVES AND PREDICTED HYDRAULIC CONDUCTIVITIES
ON A SMALL PLOT,
Cameron, D.R.
Research Station, Research Branch, Agriculture Canada, Swift Current, Saskatchewan
S9H 3X2.
Soil Science, Vol. 126, No. 6, p 364-371, December, 1978.  3 fig, 4 tab, 19 ref.

Descriptors:  Soil moisture. Soil water, Moisture content, Moisture tension,
Hydraulic conductivity, Drying, Wetting, Retention, Soil water movement.

Soil water retention curves were measured on cores taken from five sites at six
depths in a Bainsville clay loam soil.  There were differences in both the shape
and magnitude of the average moisture characteristic curves from one location to
another in the 225 sq m plot.  Coefficients of variation ranged from 4.2 to 13%
in the surface layers and from 2.4 to 6.5% in the deeper layers.  There were no
consistent trends in variability with respect to tensions from 0 to -500 cm H2O.
Predicted and measured hydraulic conductivity functions were variable, often
showing a 100-fold difference at a given water content.  The measured K functions
were steeper than those predicted, and the match between them was considered
reasonable only at the lower water contents.


78:02G-085
THEORY AND SYSTEM OF AUTOMATIC DETERMINATION OF SOIL MOISTURE CHARACTERISTICS
AND UNSATURATED HYDRAULIC CONDUCTIVITIES,
Boels, D., Van Gils, J.B.H.M., Veerman, G.J., and Wit, K.E.
Institute for Land and Water Management Research (ICW), P.O. Box 35, Wageningen,
The Netherlands.
Soil Science, Vol. 126, No. 4, p 191-199, October, 1978.  6 fig, 3 tab, 24 ref,
11 equ.
                                        56

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Descriptors:  Soil moisture, Moisture content, Water pressure, Soil water. Soil
water movement, Unsaturated flow, Hydraulic conductivity, Infiltration, Core.

The moisture characteristic and the unsaturated hydraulic conductivity were cal-
culated from the measured water pressures at different depths in a soil core and
the weights during evaporation at the'top of the core.  The measured water pres-
sure was ass'umed to represent the mean pressure in a layer of a certain thickness,
and the moisture characteristic was assumed to be described with sufficient ac-
curacy by a polynom.  The tangent of the polynom in each pressure interval was
solved from a set of equations.  The water pressure at different depths was
measured with one pressure transducer, connected with a scannivalve; the weight
was measured with a strain-gauge load cell; and the data were recorded on a
magnetic cassette tape.  The recorded data were processed by a computer and
stored on a magnetic disc.  When the saturated conductivity was relatively high,
a steady-state infiltration method was applied to determine the unsaturated
hydraulic conductivity at high water contents.


78:02G-086
TRANSPORT OF REACTIVE SOLUTES DURING TRANSIENT UNSATURATED WATER FLOW IN
MULTILAYEESD SOILS,
Selim, H.M.
Louisiana State University, Baton Rouge, Department of Agronomy, Louisiana
Agricultural Experiment Station.
Soil Science, Vol. 126, No. 3, p 127-135, September, 1978.  10 fig, 14 ref,
19 equ.

Descriptors:  Soil water movement, Soil water, Unsaturated flow, Unsteady flow,
Infiltration, Adsorption, Mathematical models.

A numerical model was developed to predict water and reactive solute transport
through water-unsaturated, multilayered soils.  An explicit-implicit finite
difference approximation method was used to solve the water and solute transport
equations simultaneously.  Calculated results were presented for two-and three-
layered soils during water infiltration and redistribution.  Linear and nonlinear
equilibrium adsorption, first-order kinetic reaction, and irreversible kinetic
reaction were used to describe solute adsorption in individual soil layers.  It
was found that, for all adsorption mechanisms considered, concentration distri-
bution during infiltration and redistribution was significantly influenced by
the order in which the soil layers were stratified.
                                      57

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                                 SECTION VIII


                                 WATER CYCLE

                              LAKES  (GROUP 02H)


78:02H-001
FIELD INVESTIGATION OF SELECTIVE WITHDRAWAL,
Ivey, G., and Imberger, J.
California University, Berkeley, Department of Mechanical Engineering.
Journal  of the Hydraulics Division, American Society of Civil Engineers, Vol.
104, No. HY9, p 1225-1237, September, 1978.  4 fig, 3 tab, 6 ref, 5 equ-, .2 append.

Descriptors:  Reservoirs, Reservoir operation, Withdrawal, Reservoir releases,
Diffusion, Viscous flow, Buoyancy, Australia.

An integral part of a reservoir management scheme is the specification of the
nature and extent of the flow within the reservoir induced by withdrawing water
at an outlet.  The steady-state thickness and extent of the withdrawal layer
were examined in this paper.  Existing theory indicated that, throughout the
study period, the withdrawal layer was in a steady state in the regime governed
by a balance between buoyancy and viscous forces.  A natural salt tracer in the
water enables estimates of the mean withdrawal layer thickness over a 10-km
(6.2-mile) length upstream from the sink for two different time periods.  To
achieve good agreement between theoretical predictions and field measurements,
it was necessary to postulate transport coefficients of momentum approximately
ten times the molecular value.  Comparisons with model simulations over the same
time period suggested an effective average Prandtl number of 20 in the hypolimnion


78:02H-002
ON THERMAL STRATIFICATION IN RESERVOIRS DURING THE WINTER SEASON,
Rahman, M.
National Research Council of Canada, Ottawa, Ontario, Division of Mechanical
Engineering.
Water Resources Research, Vol. 14, No. 2, p 377-380, April, 1978.  2 fig, 5 ref.

Descriptors:  *Thermal stratification, *Reservoirs, *Seasonal, *Diffusivity,
*Boundary processes, *Temperature profile, Numerical analyses, Heat flux, Initial
temperature, Ice.

A one-dimensional mathematical model describing the thermal structure in stratifie
reservoirs during the winter season was considered.  With the help of this model,
an attempt was made to clarify some of the physical factors which strongly in-
fluence the temperature profiles in reservoirs.  It has been observed that there
are many factors which influence the shape of the vertical temperature distribu-
tion, namely, the profile at the time of ice formation, the heat exchange by
diffusion in the water mass, the heat exchange due to inflow and outflow of water
in reservoirs, etc.  This model accounts for a qualitative assessment of the
possible effects of diffusivity and the initial shape of the temperature profiles
on the variation of the vertical temperature distribution.
                                     58

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                                   SECTION IX


                                   WATER CYCLE

                          WATER AND PLANTS (GROUP 021)


78:021-001
IRRIGATION EFFECTS ON VEGETATIVE AND REPRODUCTIVE DEVELOPMENT OF THREE SOYBEAN
CULTIVARS,
Ashley, D.A., and Ethridge, W.J.
Goergia University, Athens, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 3, p 467-471, May-June,
1978.  6 tab, 13 ref.

Descriptors:  Soybeans, Supplemental irrigation, Growth stages, Plant growth,
Irrigation effects.

This field experiment considered four moisture regimes—no irrigation, full
season irrigation, irrigation starting at bloom stage,  and irrigation starting
at pod fill stage-on three soybean cultivars, "Ransom", "Hamptom 266A", and
"Coker 102".  Data were collected for seed yield, pod number and dry weight,
dry weight of vegetative components during reproductive development and seasonal
soil moisture status.  The soil was a sandy loam.  Full season and bloom stage
irrigation treatments produced higher yields than the unirrigated check except
for Hamptom 266A in 1974.  Yields from plants receiving the podfill stage
irrigation treatment were higher than the unirrigated check in drier seasons of
1972 and 1973 but not in 1974.  Irrigation beginning at pod fill produced yields
equal to the full season and bloom stage treatments in some cases and somewhat
lower yields in other cases.  Water application prior to blooming greatly in-
creased vegetative dry weight, number, and dry weight of pods.  Beginning irri-
gation during reproductive development had little effect on vegetative dry
weight, but usually resulted in a greater number of pods late in the season
than the unirrigated check.  Higher yields and greater response to irrigation
were obtained from shorter Ransom plants than the other two cultivars.


78:021-002
IRRIGATION TIMING—ITS INFLUENCE ON THE EFFECTS OF SALINITY AND WATERLOGGING
STRESSES IN TOBACCO PLANTS,
West, D.W., and Black, J.D.F.
Horticultural Research Institute, Victoria, Australia,  Department of Agriculture.
Soil Science, Vol. 125, No. 6, p 367-376, June, 1978.  1 fig, 4 tab, 33 ref.

Descriptors:  Saline water. Water quality, Sodium chloride, Drainage, Soil-water-
plant relationships, Oxygen, Irrigation, Diffusion, Growth chambers, Tobacco.

The effects of irrigation timing on the interaction between salinity and water-
logging, and changes in the oxygen status in the root zone of a heavy soil under
tobacco plants irrigated with drip system were studied.  Water uptake was
significantly reduced by the presence of NaCl in the root zone irrespective of
irrigation and drainage treatment.  Leaf chloride in all nonsalinized treatments
was significantly lower than in all salinized treatments.  Both day and night
waterlogged saline treatments contained significantly higher leaf chloride than
the nonwaterlogged saline treatment.  The night-waterlogged saline treatment
contained significantly lower leaf chloride than the day-waterlogged saline
treatment.  Similar trend to high Cl(-) content with day waterlogging was present
with petioles and stems.  Root Cl(--} concentrations were relatively low irrespective
of treatment.  Leaf sodium concentrations were relatively low irrespective of
treatment.  Leaf sodium concentrations of day- and night-waterlogged saline
treatments were significantly higher than all other treatments, and the day-
waterlogged salinized plants had significantly higher leaf Nat than the night-
waterlogged salinized plants.  The results suggests that plants in a soil with
some chance of being waterlogged in the root zone and with NaCl present in the
root zone would benefit from being irrigated at night rather than during the day.
                                      59

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78:021-003
CROP WATER REQUIREMENT IN RELATION TO CLIMATE AND SOIL,
Shalhevet, J-, and Bielorai, H.
Institute of Soils and Water, Bet Dagan, Israel, ARO-The Volcani Center.
Soil Science, Vol. 125, No. 4, p 240-247, April, 1978.  2 fig, 4 tab, 22 ref.

Descriptors:  Water requirements, Yield equation. Climatic data, Soil properties,
Cotton, Sorghum, Grapefruit, Evapotranspiration, Evaporation, Pans, Correlation
analysis.

The effect of variation in climate and soil on the production function of water
for the yield of cotton, sorghum, and grapefruit was analyzed to determine the
transferability of water requirement information, accumulated in Israel, to
other regions of the world.  A model giving relative yield (Y) as a linear
function of relative evapotranspiration (EK/EQ) for all climatic regions together
was compared with regional relationships of Y to net water application.  Y is the
ratio of a treatment yield to the maximum yield obtained in an experiment; Et
and E0 are the cumulative seasonal evapotranspiration, including a small drainage
component, and pan evaporation, respectively.  The correlation coefficients were
high for field crops but smaller for citrus.  About 90 percent of the variability
in yield of field crops were attributed to differences in potential evapotranspira-
tion and in irrigation amounts.  No effect was found of variation in soil on crop
yield due to the rather uniform water-storage capacity of soils of varying texture.
It was proposed that the production functions obtained in Israel may be used in
regions with similar climatic characteristics for a wide range of soils after
accounting for climatic variations through pan evaporation estimates.


78:021-004
SIMULATED PLOW THROUGH THE ROOT XYLEM,
Busscher, W.J., and Fritton, D.D.
Rutgers University, New Brunswick, New Jersey, Department of Soils and Crops.
Soil Science, Vol. 125, No. 1, p 1-6, January, 1978.  5 fig, 14 ref, 5 equ.

Descriptors:  Xylem, Root systems, Flow resistance, Flow rates, Simulation
analysis, Model studies, Water pressure, Evapotranspiration.

Flow through the xylem of a complex root system is simulated to measure xylem
resistance to water flow, and to determine whether or not this resistance
is significant.  Equations are set up that model xylem water flow as if it were
flow through thin tubes.  The root characteristics needed to solve these equations
are obtained from an earlier work.  Xylem water flow is first considered foz a
single main root and its laterals.  It decreases with age of the root or in-
crease of root length, and it increases with the addition of laterals.  The
advantage of an increasing number of main roots is also shown.  Finally, flow
through the plant crown is compared to Thornthwaite and Blaney-Criddle evapo-
transpirational estimates.  Less than 10 millibars of water pressure is needed
to overcome xylem resistance, and, therefore, the resistance is considered
negligible.


78:021-005
RELATIONSHIP BETWEEN SOIL TEST AND SMALL GRAIN RESPONSE TO P FERTILIZATION IN
FIELD EXPERIMENTS,
Fixen, P.E., and Carson, P.L.
South Dakota State University, Brookings,  Department of Plant Science.
Agronomy Journal, Vol. 70, No. 5, p 838-844, September-October, 1978.  3 fig, 8 tab/
35 ref.

Descriptors:  Soil tests, Fertilization, Phosphorus, Grains (crops), 'Correlation
analysis, Regression analysis, Climatic data, Soil properties, Crop response,
Organic matter.

Yield data from 74 small grain field experiments over a 13-year period were used
to evaluate the relationship between various soil tests and P response.  The soil
tests examined in this study were the Bray 1 (soil to solution ratio of 1:7, 1:10,
1:20, and 1:50), Olsen P, and P sorption index of Bache and Williams.  The crop
species included were Triticum aestivum L., Hordeum vulgare L., and Avena sativa
L.  The highest correlation between soil test value and yield response P


                                      60

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                                                 2
 fertilization was found with the Bray 1, 1:50 (r  = 0.41).   An additional 23%
 of the yield response variation could be explained by including six
 additional variables in a multiple regression analysis employing dummy
 variables.  The r value between P sorption index and yield  response on alkaline
 soils was -0.70 but was near zero for. acid soils.  Differences were also noted
 in degree of response between parent materials and crop species.  Organic
 matter content appeared to influence response on some soils.


 78:021-006
 ALFALFA WATER USE AND PRODUCTION ON DRYLAND AND IRRIGATED SANDY LOAM,
 Bauder, J.W.,  Bauer, A., Ramirez, J.M.,  and Cassel, D.K.
 North Dakota State University,  Fargo,  Department of Soils.
 Agronomy Journal, Vol.  70,  No.  1, p 95-99,  January-February,  1978.   2  fig,  3  tab,
 12 ref.

 Descriptors:   Alfalfa,  Irrigation effects,  Soil-water-plant relationships.
 Moisture stress,  Evapotranspiration, Fertilization, Crop  production, Great  Plains,
 Correlation analysis.

 This  study was carried  out on a Maddock  sandy loam soil,  a  member of the sandy,
 mixed frigid Udorthentic Haploboralls.   Four irrigation levels,  ranging  from
 dryland to excessive irrigation,  were  established as whole  plots in a  randomized
 block,  split plot design.   Eight different  fertilizer  treatments of P, K, and  S
 were  applied to split plots during the 1st  year  of the study.   Under a three
 harvest per season management system dry matter  yield  was significantly  affected
 by harvest number and irrigation treatment  each  year.   Within  the dryland and
 deficient irrigation treatment  by year,  yields decreased with  each  cutting; with
 optimum and excessive irrigation,  yields varied  inconsistantly with cutting,
 yields  increased  14 to  330% over dryland by increasing irrigation applica-
 tions.   When plant water stress existed  throughout the growing season, relative
 yield correlated  with relative  evapotranspiration in a near perfect, linear
 manner.   Under  nonstress conditions, irrigation,  growing season  precipitation,
 and soil water  depletion required consideration  to attain nearly perfect correla-
 tion  of  relative  yield  with relative evapotranspiration.  The  results of this
 study indicated that under  plant water stress conditions, alfalfa dry matter
 yield is a linear function  of plant water use.


 78:021-007
 NUTRIENT UPTAKE BY GRASS AND LEACHING LOSSES FROM SOLUBLE AND  S-COATED UREA AND
 KC1,
 Allen,  S.E., Terman, G.L.,  and  Kennedy,  H.G.
 National  Fertilizer  Development Center,  TVA, Muscle Shoals,  Alabama, Soils and
 Fertilizer Research  Branch.
 Agronomy  Journal,  Vol.  70,  No.  2, p 264-268, March-April, 1978.  4 fig,  4 tab,
 6  ref.

 Descriptors:  Leaching,  Fescues, Sudangrass, Nutrients, Fertilizers, Nitrogen,
 Potassium,  Crop response, Lysimeters, Ureas.

 Slow-release fertilizers should provide  for more efficient nutrient use by the
 crop  as well as reduce  leaching losses.  This study was conducted to measure
 crop  response to N or K  in  uncoated urea, ammonium nitrate,  S-coated urea, and
 S-coated KC1 and to  relate  leaching losses to N03 - N and cations.   In one
 series, granular N sources  to supply 200 or 400 kg of N/surface ha were mixed with
 the upper  20 cm of a 1:1 mixture of Norfolk si (Typic Paleudult) and builders sand
 contained  in 15 cm by'120 cm columns.  A second series was similarly fertilized with
K  sources  to supply  100 or  200 kg of K/surface ha.


 78:021-008
 ROOT-SINK DESCRIPTIONS OF WATER SUPPLY TO DRYLAND WHEAT,
 Rickman, R.W.,  Allmaras, R.R., and Ramig, R.E.
Oregon State University, Pendleton, Columbia Plateau Conservation Research Center.
Agronomy Journal, Vol.  70, No. 5, p 723-728, September-October, 1978.   11 fig,
 13 ref, 4 equ.
                                      61

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Descriptors:  Moisture uptake, Wheat, Moisture tension, Soil water movement, Soil
profiles, Root distribution, Dry farming, Soil-water-plant relationships, Sink,
Hydraulic conductivity.

Soil water content changes were supplemented with calculations of water flow
between soil layers to provide an improved description of water uptake by dry-
land wheat (Triticum aestivum L.).  Water content changes were estimated from
neutron meter measurements.  Soil water flux was estimated from field measure-
ments of both hydraulic conductivity and hydraulic head gradients; unsaturated
conductivity beyond the range of field measurement was calculated with the pore
interaction model of Marshall matched to field measured values at 250 mb.
Seasonal water-uptake patterns, determined by the root-sink description, differed
from those shown by only water content measurements.  Peak water-use rates did
not coincide with maximum leaf area index, but coincided with the period from
heading to completed head extension.  Water flux in the profile was important for
supplying water during grain filling and was critical in this layered soil,
which restricted rooting to depths less than 150 cm.


78:021-009
FERTILIZER PLACEMENT EFFECTS ON SOYBEAN SEED YIELD, N2 FIXATION, AND 33P UPTAKE,
Ham, G.E., and Caldwell, A.C.
Minnesota University, St. Paul, Department of Soil Science.
Agronomy Journal, Vol. 70, No. 5, p 779-783, September-October, 1978.  2 fig,
4 tab, 20 ref.

Descriptors:  Nitrogen fixation, Soybeans, Phosphorus, Radioisotopes, Fertilizers,
Ureas, Seeds, Productivity.

This study was planned to evaluate the efficiency of P fertilizer utilization
by field-grown soybeans with different fertilizer placements using 33P labelled
fertilizer (35 kg P/ha) on a Waukegan silt loam soil  (Typic Hapludoll) low in
plant available N and P.  In addition, urea (30 kg N/ha) labelled with 15N was
added to measure the effect of P fertilizer placement on N uptake and N2 fixation
using the "A" value concept concerning the measurements of available soil nutrients
developed by Fried and Dean (1952).  Soybean seed yield and total P uptake were
increased significantly by adding P fertilizer with no differences among the
fertilizer placements  (seed yield ranged from 3,811 to 4,035 kg/ha compared to
3,200 kg/ha for the control).  The 33P labelled fertilizer provided a direct,
quantitative measure of the efficiency of plant use of the added P and provided
a basis of evaluating the fertilizer placements without the hazards associated
with 33P over the 149-day experiment.  The "A" value concept provided a reliable
estimate of N2 fixation which agreed with Kjeldahl measurements.


78:021-010
DIFFERENTIAL RESPONSE OF SOYBEAN VARIETIES TO SOIL CADMIUM,
Boggess, S.F., Willavize, S.,  and Koeppe, D.E.
Illinois University, Urbana, Department of Agronomy.
Agronomy Journal,  Vol. 70, No.  5, p 756-760,  September-October,  1978.   1 fig, 5 tab,
30 ref.


Descriptors:   Cadmium, Toxicity, Soybeans, Varieties,  Crop response,  Sewage sludge,
Soil amendments,  Trace elements.

This paper presents the results of a comprehensive survey of the Cd uptake and
effect by a number of the prominent soybean (Glycine max (L.)  Merrill)  varieties
grown on several CdC12 or sewage slude-amended soils in the glasshouse'.   In all
varieties,  Cd toxicity symptoms appeared as a continuum from slight effects ob-
served as a red,  red-brown,  or purple coloration at the junction of the leaf
blade and petiole,  to severe leaf curling and extensive reddening of the leaf
veins,  chlorosis,  and finally a brittle condition followed by abscission of the
leaves.  All  varieties showed increased shoot Cd concentration and decreased dry
weight in response to soil CdC12, but varietal differences in the severity of
these Cd effects were observed.   Further analysis of data for Cd susceptibility
suggested that,  of the soybean varieties tested on CdC12-amended soils,  Dunfield,
Harosoy, Arksoy,  Dare, Flambeau, and Scioto were generally the most susceptible
while Clark,  Mandarin, Mukden,  Jackson,  and Lee were consistently ranked as less
susceptible.

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78:021-011
SEEDLING EMERGENCE AS RELATED TO TEMPERATURE AND MOISTURE TENSION,
Wright, D.L., Blaser, R.E., and Woodruff, J.M,
Florida University, Quincy.
Agronomy/Journal, Vol. 70, No. 5, p 709-712, September-October, 1978.  1 fig,
1 tab, 16 ref.

Descriptors;  Erosion control, Grasses, Legumes, Highway beautification,
Germination, Seeds, Moisture tension, Temperature.

To aid in selection of species for mixtures of seed for controlling erosion on
newly constructed highway slopes, an experiment was designed to determine total
emergence and rates of emergence of several grass and legume species and cultivars
under various soil moisture and temperature regimes.  The experimental observa-
tion suggested that the aggressive species of annual and perennial ryegrass,
German millet, redtop, weeping lovegrass, and Abruzzi rye compete strongly with
slower developing perennial grasses and legumes when seeded in the appropriate
season.  It was also observed that successful establishment of the intermediate
species such as bluegrass, crownvetch, creeping red fescue, and Kentucky 31 tall
fescue depends on cool temperatures and high moisture availability.  Nonaggressive
species of crownvetch and sericea also required high moisture and cool temperature,
whereas common bermudagrass needed high moisture and warm temperatures.  It was
concluded that modification of seed mixtures should depend on the season of
seeding and the type of vegetation, desired, and that lower rates of agressive
species should be used while seeding mixtures of aggressive species with slow-
developing species when conditions favor rapid emergence and growth for both.


78:021-012
DIFFERENCES AMONG GENOTYPES OF CORN IN THE KINETICS OF P UPTAKE,
Nielsen, N.E., and Barber, S.A.
The Royal Veterinary and Agricultural University, Copenhagen, Denmark.
Agronomy Journal, Vol. 70, No. 5, p 695-698, September-October, 1978.  6 tab,
23 ref, 1 equ.

Descriptors:  Corn (field), Phosphorus, Simulation analysis, Soil properties,
Root systems, Correlation analysis.

Many plant species utilize fertilizer of soil P inefficiently.  A survey of 12
inbred corn genotypes (Zea mays L.) grown in water culture indicated a 1.8 to 3.3-
fold variation in root weight, root length per unit of plant weight, root length
per unit of root weight, and maximal net P influx.  Some aspects of the role of
genetics were elucidated by comparing the P absorption parameters of five inbreds
with those of four single-cross hybrids made from these inbreds.  Five single
crosses were grown at low and high P levels in the field on a Raub silt loam
(Aquic Argiudoll) to test the significance of the measured root parameters on P
uptake.  Plants were harvested 22, 38 and 51 days after planting.  Phosphorus
uptake was also simulated by a model using soil and plant root parameters related
to P uptake.  The correlation between predicted and observed P uptake was r2 =
0.90 for the 22 to 38-day time interval and r2 =0.98 for the 22 to 51-day time
interval.   Hence, observed differences among corn single crosses in their plant
root parameters were reflected in their P uptake when grown in the field.


78:021-013
TEMPERATURE DEPENDENCE OF WATER UPTAKE BY PLANT ROOTS,
Dalton, F.N., and Gardner, W.R.
Wisconsin University, Madison, Department of Soil Science.
Agronomy Journal, Vol. 70, No. 3, p 404-406, May-June, 1978.  4 fig, 1 tab, 11 ref,
13 equ.

Descriptors:  Moisture uptake, Root systems, Temperature, Solutes, Kinetics,
Diffusivity.

The transport of water through root membranes is described in terms of equations
which couple water and solute transport.  The solute transport equation includes
active as well as passive uptake.  Temperature effects are manifested in the
viscosity of water, the osmotic permeability coefficient of the membranes, and the
rate constant for the active solute uptake.  From standard reaction rate kinetics,
reasonable estimates of the temperature coefficients of these three processes are made.

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A general equation  for the effect of temperature on the uptake rate for a given
driving  force  is derived.  This difference in flux between live and dead roots
is adequately  described by the model, indicating the significance of the active
component of the uptake process.


78:021-014
INFLUENCE OP K ON THE UPTAKE, TRANSLOCATION, AND REDUCTION OF NITRATE BY BARLEY
SEEDLINGS,
Blevins, D.G., Hiatt, A.J., Lowe, R.H., and Leggett, J.E.
Kentucky University, Lexington, Department of Agronomy.
Agronomy Journal, Vol. 70, No. 3, p 393-396, May-June, 1978.  5 fig, 1 tab, 17 ref-

Descriptors:   Nitrates, Translocation, Reduction (chemical), Barley, Organic
acids, Metabolism,  Calcium, Potassium, Growth chambers.

The purpose of this study was to determine the influence of K or Ca on nitrate
uptake, translocation, and reduction in barley seedlings.  Six-day-old barley
seedlings were grown for 2 to 36 hours in solutions of 1.0 meg/liter KN03 or Ca
(NO3)2, each containing 0.4 meq/liter of CaS04.  Experiments were conducted in a
growth chamber at 27 C with a photosynthetic irradiance of 5.3 mW times cm-3.
Seedlings treated with Ca(N03)2 (low K) had lower levels of nitrate uptake, nitrate
reductase activity, and lower organic acid concentrations than seedlings treated
with 1 mM KN03.  The solution pH and the expressed sap pH of roots and shoots of
the low K seedlings increased during the experiment.  The shoots of the low-K
seedlings had  much  lower nitrate concentrations and lower levels of nitrate reduc-
tase activity  than  the roots, suggesting that K plays a major role in nitrate
translocation.  These results support the hypothesis that potassium malate is
cycled from the tops to the roots where decarboxylation occurs, providing a source
of HCO3(-) for exchange with NO3(-) during absorption.


78:021-015
RESPONSES OF STOMATA AND WATER, OSMOTIC, AND TURGOR POTENTIALS OF JOJOBA TO WATER
AND SALT STRESS,
Adams, J.A., Bingham, F.T., Kaufmann, M.R., Hoffman, G.J., and Yermanos, D.M.
California University, Riverside, Department of Soil and Environmental Sciences.
Agronomy Journal, Vol. 70, No. 3, p 381-387, May-June, 1978.  4 fig, 2 tab, 42 ref-

Descriptors:   Desert plants, Soil-water-plant relationships, Salt tolerance.
Drought tolerance;  Turgidity, Transpiration, Stomata, Xylem.

Jojoba (Simraondsia  chinensis (Link) Schneider) is a desert shrub which can provide
a much needed  substitute for sperm whale oil.  Because of the absence of soil-
plant-water data for jojoba and the limited amount of such information for desert
plants in general,  selected plants were water-and-salt-stressed in greenhouse soil
and sand culture experiments.  Responses of leaf water, osmotic, and turgor poten-
tials to stress and associated stomatal behavior were studied.


78:021-016
FORAGE YIELD AND FERTILIZER RECOVERY BY THREE IRRIGATED PERENNIAL GRASSES AS
AFFECTED BY N  FERTILIZATION,
Hanson, C.L.,  Power, J.F., and Erickson, C.J.
Northwest Watershed Research Center, Boise, Idaho, United States Department of
Agriculture.
Agronomy Journal, Vol. 70, No. 3, p 373-375, May-June, 1978.  3 tab, 5 ref.

Descriptors:   Forage grasses. Hay, Nitrogen, Fertilization, Crop response,
South Dakota.

The purpose of this study, conducted in western South Dakota on heavy clay soils
was to determine forage yield responses and N recovery of three irrigated grasses-'
reed canarygrass, garrison creeping foxtail, and smooth brome—to single and split
N applications.  Single N treatments consisted Of 0, 56, 112, 224, or 448 kg N/ha
applied in March.  For the split N applications, these same rates were applied
both in March  and again after the first hay fritting.  Forage yields were maximum
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when the grasses were fertilized with 224 kg N/ha in the split applications.  First
cutting forage N percentage varied between 0.8 to 2.8 for N rates of 56 kg N/ha
and above.  The percentage of N was highest, frequently over 3%, in second cutting
forage from treatments receiving split fertilizer applications.  Percent total
N recovered increased as fertilizer rate increased when all N was applied in March,
but recovery was highest for the split application of 224 kg N/ha.


78:021-017
EFFECT OF SLOW RELEASE FERTILIZER ON FERTILIZER RESIDUES AND ON YIELD AND
COMPOSITION OF FLUE-CURED TOBACCO,
San Valentin, G.O., Robertson, W.K., Johnson, J.T., and Weeks, W.W.
Philippines University, Banos College, Laguna 3720, Philippines, Department of
Agriculture.
Agronomy Journal, Vol. 70, No. 2, p 345-348, March-April, 1978.  9 tab, 7 ref.

Descriptors:  Tobacco, Potassium, Fertilizers, Solubility, Nutrient removal,
Sulfur.

Tobacco was grown for 5 years on Lakeland fine sandy soil, a soil which retains
very little K.  Split applications of K2SO4 were compared to single applications
of K2SO4 and resin- polyvinyl-, and S-coated K materials.  Yields and chemical
composition of tobacco leaves and soil were used to measure the relative effective-
ness of K treatments.  Yields and K contents of tobacco leaves were increased by
K fertilization.  Split applications of K2S04 were more effective than single
applications at planting.  In years with heavy rainfall, applying slowly-soluble
sources all at planting was better than applying K2SO4 in split application.
Potassium from slowly soluble materials was less readily leached than from K2SO4,
resulting in higher concentration of K within 60 cm of the surface at the time of
tobacco flowering.  When various thickness of S were applied to give a range of
K release, the thicker coatings gave higher yields.  Treatments that provided
higher K contents increased total alkaloids and decreased reducing sugars in the
first of the two years that they were measured.  Application of K fertilizers
with reduced solubility should assure good yields, quality, and a high level of
K in tobacco.


78:021-018
DRY MATTER PRODUCTION AND TRANSLOCATION IN MAIZE SUBJECTED TO DROUGHT DURING
GRAIN FILL,
Jurgens, S.K., Johnson, R.R., and Boyer, J.S.
Illinois University, Urbana, Department of Agronomy.
Agronomy Journal, Vol. 70, No. 4, p 678-682, July-August, 1978.  5 fig, 5 tab,
17 ref.

Descriptors:  Corn  (field), Moisture stress, Moisture deficit, Photosynthesis,
Translocation, Crop response, Crop production.

The objective of this research was to study the problem of yield loss to be
expected and the physiological mechanism that cause the loss due to dry condi-
tions most frequently occurring during the second half of the growing season of
maize  (Zea mays L.).  Drought was imposed during-the grain filling stage of
maize to determine Its relative effects on photosynthesis and translocation.


78:021-019
EFFECTS OF SOIL WATER STRESS ON GROWTH AND NUTRIENT ACCUMULATION IN CORN,
Verasan, V., and Phillips, R.E.
Kasetsart University, Bangkok, Thailand, Department of Soil Science.
Agronomy Journal, Vol. 70, No. 4, p 613-618, July-August, 1978.  6 fig, 10 ref.

Descriptors:  Moisture stress, Moisture deficit, Corn (field), Plant growth,
Nutrients, Plant physiology, Transpiration, Moisture tension.

The objective of this study was to more clearly delineate the effect of soil
water stress on growth and accumulation of nutrient ions in corn.  Corn was
grown in the greenhouse in 20-liter pots containing soil from the Ap horizon
of Maury silt loam  (Typic Paleudalfs) under two soil moisture treatments,
stressed and nonstressed.  The relationship soil water potential and cumulative
evapotranspiration with nutrient accumulation and dry matter production were
more significant than the relationship of soil water potential with dry matter
                                       65

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 production  and  nutrient  accumulation.  Since water  stress affects  turgidity,
 photosynthesis,  respiration,  cell  enlargement, and  other physiological processes
 of  the  plant, it was  concluded  that  cumulative transpiration  is a  better integrator
 of  the  effects  of  these  processes  on plant growth than  is soil water potential.


 78:021-020
 FIELD MEASURED  AND SIMULATED  CORN  LEAF WATER POTENTIAL,
 Reicosky, D.C.,  and Lambert,  J.R.
 Agricultural Research Service,  Morris, Minnesota, United States Department of
 Agriculture.
 Soil Science Society  of  America Journal, Vol. 42, No. 2, p 221-228, March-April,
 1978.   6 fig, 2  tab,  27  ref.

 Descriptors:  Sweet corn, Simulation analysis. Moisture content, Moisture tension,
 Microenvironment,  Stemflow.

 The dynamic nature and magnitude of  field-measured  leaf water potential for sweet
 corn (Zea mays L.) was compared with that predicted by the model TROIKA.  Some
 plant parameters for  corn were  estimated from the literature and field observa-
 tion, whereas the  moisture desorption curve and the hydraulic conductivity-water
 content relationship  were determined for the Varina sandy loam.  Leaf water po-
 tential-relative water content  relationships were determined in the greenhouse.
 Hourly microclimate data were used as input to the model, and the  predicted and
 observed value of  leaf water potential were compared for 3 days during the growing
 season.  Generally, the model predicted leaf water potential with  reasonable
 accuracy throughout the  day.  Water  potential gradients in the soil were small as
 compared with those across the  root  and across the stomatal opening.


 78:021-021
 POTASSIUM UPTAKE BY ONION ROOTS CHARACTERIZED BY POTASSIUM/RUBIDIUM RATIO,
 Baligar, V.C., and Barber, S.A.
 Purdue University, Lafayette, Indiana, Department of Agronomy.
 Soil Science Society  of America Journal, Vol. 42, No. 4, p 618-622, July-August,
 1978.  8 tab, 15 ref, 3 equ.

 Descriptors:  Cations, Cation exchange, Potassium, Onions, Sweet corn, Selectivity,
 Diffusivity, Root  systems.

 A common belief is that plant roots  absorb cations from the solution phase of the
 soil.  Experiments with corn  (Zea mays L.)  using K/Rb ratio to evaluate the source
 of K and Rb absorbed  indicated  the plant roots absorbed these ions in the ratio
 of exchangeable K  and Rb.  The objective of this research was to study the source
 of K and Rb absorbed  from soil by onion (Allium cepa) roots since  they do not have
 root hairs and this may influence the uptake mechanism.  Onions absorbed K/Rb with
 a ratio which was  intermediate between the ratio of exchangeable K and Rb and the
 ratio of these cations in solution.  In comparison with corn, onions absorbed K
 at one-third the rate, but absorbed water three times faster so that mass flow
 contributed a greater proportion of K absorbed by onions than that by corn.  This,
 rather than differences in root hairs may be the reason for the observed differences
 in K uptake between corn and onions.


 78:021-022
 UPTAKE OF CADMIUM FROM PHOSPHATE FERTILIZERS BY PEAS, RADISHES, AND LETTUCE,
 Reuss,  J.O., Dooley,   H.L., and Griffis, W.
 Corvallis Environmental Research Laboratory, Corvallis, Oregon  97330.
 Journal of Environmental Quality, Vol. 7,  No. 1,  p 128-133,  January-March,  1978.
 2 fig,  7 tab, 6 ref.

 Descriptors:  Heavy metals, Phosphates, Fertilizers, Cadmium.

 Cadmium uptake from phosphate fertilizers by radish, lettuce, and garden peas was
 investigated in the greenhouse.   Reagent grade mono-calcium phosphate and concen-
 trated superphosphate (CSP)  were used as a P source on a coarse-textured acid soil.
The effect of mono-calcium phosphate compared with that of CSP on radish,  lettuce
 and peas was nonsignificant.  On a medium-textured calcareous soil the use  of this
CSP increased the Cd  content of radish tops by about 80% and that of lettuce  by 50%.


                                      66

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  The effect on radish roots from calcareous soil was nonsignificant.  Pea seeds
  and foliage on this soil were below our Cd detection limit.  Uptake on both
  soils was a linear function of the Cd content of the fertilizer.  In the acid
  soils, spot placement of fertilizer in comparison to mixing it with the soil re-
  sulted essentially the same Cd uptake from CSP fertilizer.  Spot placement of
  Di-ammonium phosphate (DAP) almost completely eliminated Cd uptake from the
  fertilizer.  In the calcareous soil spot placement increased Cd uptake from the
  CSP fertilizer, but slightly depressed uptake from DAP.


  78:021-023
  USE OF K/Rb RATIO TO CHARACTERIZE POTASSIUM UPTAKE BY PLANT ROOTS GROWING IN
  SOIL,
  Baligar,  V.C.,  and Barber,  S.A.
  Purdue University, West Lafayette,  Indiana,  Department of Agronomy.
  Soil Science Society of America  Journal,  Vol.  42,  No.  4,  p 575-579,  July-Auaust
  1978.   3  fig,  5 tab,  18  ref,  2 equ.

  Descriptors:  Potassium,  Root systems,  Root  development,  Moisture uptake, Ion
  exchange,  Sweet corn, Growth  chambers.

  Interaction between the  plant root and  the soil on  cation influx  into the root
  is  not well understood.   Use  of  the ratio of K/Rb,  two  ions  absorbed inter-
  changeably by the  root,  enables  measurement of the  K  ion  medium influencing K
  influx into the root.  In experiments with corn (Zea mays  L.) grown in eight
  soil-R systems  in  a growth  chamber, the K/Rb ratio  of uptake was  similar to the
  K/Rb ratio of the  ions on the  exchange sites, and not the  K/Rb ratio of the
  solution cations.  The data may be interpreted to indicate that K and Rb on the
  exchange sites had more influence on K and Rb flux  into the root than K and Rb in
  solution.   Diffusion of K and  Rb from the soil to H-saturated exchange membranes
 was in the  ratio of K/Rb  in solution.


  78:021-024
 GROWTH AND ELEMENTAL COMPOSITION OF CORN AND BEAN SEEDLINGS AS INFLUENCED BY SOIL
 APPLICATION OF COAL ASH,                           '
 Adriano,  D.C., Woodford, T.A., and Ciravolo,  T.G.
 savannah River Ecology Laboratory, P.O.  Drawer E,  Aiken, South Carolina  29801.
 Journal of Environmental Quality, Vol. 7,  No. 3,  p 416-421, July-September,  1978.
 5 tab,  43 ref.

 Descriptors:  Coal mine wastes, Corn (field), Beans, Crop production, Soil chemical
 Properties, Fossil fuels,  Fly  ash,  Toxicity,  Salinity,  Deficient elements.

 Analyses  of O.lN HC1 extracts  of ash (slag +  fly ash)  samples from bituminous coal
 •revealed  high concentrations of K,  Ca, and Fe and  intermediate concentrations of P,
 M9/  Cu, Mn, and  Zn.  Of  the  elements  analyzed,  the extractable concentrations in-
 creased as  particle size  decreased from  >1,000  micron to <105 micron.  The slightly
 acidic  ashes were  mixed with Troup sandy loam at rates of  5,  10, and  20% by weight
 and  equilibrated in a glasshouse  for  1 mo  before planting.   "Coarse" ash was used
 at only the 10%  rate.  Corn  and bush bean  yields from ash-amended  soils were
 statistically equal to yields  from a control  treatment but  significantly lower than
 fertilized  treatment.  Corn  exhibited P deficiency symptoms while  symptoms charac-
 teristic of B  toxicity occurred in beans.  Analyses  of tissues of both crops indi-
 cated that  P concentrations  were  at deficiency levels while Cu, Mn, and Zn were
 deficient to marginal.  Iron, however, appeared to be in the normal range.
 Salinity as indicated by EC  of  leachate of 3 mmhos/cm or greater, B excess as
 indicated by the toxicity  symptoms in beans, and P deficiency as indicated by
 low p concentrations in plant tissues could limit crop growth in ash-treated soils.


 78:021-025
 CORN PRODUCTION AS  INFLUENCED BY IRRIGATION AND SALINITY—UTAH STUDIES,
Hanks,  R.J., Ashcroft, G.L., Rasmussen, V.P., and Wilson, G.D.
°tah State  University, Logan, Department of Soil Science and Biometeorology.
 Irrigation  Science, Vol. 1, No. 1, August,  1978, p 47-59.  9 fig, 3 tab,  8 ref.

Descriptors:  Irrigation, Salinity, Corn (field),  Moisture stress,  Moisture deficit,
Growth stages, Saline water,  Evapotranspiration, Crop production, Crop response.


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This paper reported the results of a two-year field study at Logan, Utah which
was one of a series of similar experiments carried out at Fort Collins, Colorado,
Davis, California and Yuma, Arizona.  A range of water application rates were
imposed using a line-source system and in some treatments water was withheld
during certain growth stages.  Salinity variables were imposed by presaliniza-
tion before planting and by the use of saline irrigation water.  Regardless of
irrigation or salinity regime, corn grain and total dry matter production were
linearly related to evapotranspiration, which was measured as the sum of irriga-
tion, rainfall and soil water depletion minus drainage.  Presalinization of the
soil decreased yields in proportion to the salinity imposed, the decrease being
associated with reductions in evapotranspiration caused by reduced soil water
depletion as compared to the nonsalinized treatments.


78:021-026
THE EFFECT OF SUPPLEMENTAL IRRIGATION AND NITROGEN FERTILIZATION ON WHEAT
(TRITICUM AESTIVUM L.),
Shimshi, D., and Kafkafi, U.
Regional Experiment Station, Agricultural Research Organization, Mobile Post
Negev 2, Gilat, Israel.
Irrigation Science, Vol. 1, No. 1, August, 1978, p 27-38.  2 fig, 7 tab, 13 ref.

Descriptors:  Supplemental irrigation, Fertilization, Nitrogen, Wheat, Crop
response, Crop production. Growth stages.

During 1971/72 an experiment was conducted at the Gilat Regional Experiment
Station in the Negev region of Israel, in which the combined effect of irrigation
and nitrogen fertilizer on wheat was studied.  The following aspects were investi-
gated:  the general nature of the interaction of irrigation and nitrogen on crop
yields and the effect of nitrogen on water use and water relations of the wheat
plant.


78:021-027
EFFECTS OF CHELATED IRON ON THE GROWTH OF TWO SPECIES OF VALLISNERIA,
Dooris, P.M., and Martin, D.F.
South Florida University, Tampa, Department of Biology and Chemistry.
Water Resources Bulletin, Vol. 14, No. 5, p 1088-1093, October, 1978.  4 tab,
12 ref.

Descriptors:  Aquatic plants, Iron, Nutrient requirements, Plant growth, Florida,
Water management (applied).

Iron, added as (Fe-EDTA)(-), was found stimulatory to V. spiralis at a concen-
tration of 0.05 ppm.  (Fe-EDTA)(-) had no effect upon growth of V. neotropicalis
as measured by changes in dissolved oxygen and dry weight.  Results were compared
with those derived from similar studies with Hydrilla verticillata and Egeris
densa.  The implications of lake drawdown and aeration were discussed.


78:021-028
ABSORPTION RATES OF AMMONIUM AND NITRATE BY RED KIDNEY BEANS UNDER SALT AND WATER
STRESS,
Frota, J.N.E., and Tucker, T.C.
Arizona University, Tucson, Department of Soil, Water and Engineering.
Soil Science Society of America Journal, Vol. 42, No. 5, p 753-756, September-
October, 1978.  2 fig, 5 tab, 21 ref.

Descriptors:  Salinity, Moisture stress. Absorption, Ammonium salts, Nitrates,
Beans, Moisture deficit. Crop production. Crop response, Nitrogen.

The purpose of this study was to gain additional knowledge regarding the influence
of salinity and water deficit on plant uptake of NH4(+) and NO3(-).  The absorption
patterns of NH4(+)  and N03(-) by red kidney beans (Phaseolus vulgaris L.) were
determined under normal conditions  (water stress) using an inverse isotope dilution
technique with 15N.  Salt and water stress inhibited the absorption of both NH4(+)
and NO3(-).  There was no difference between these two stress treatments in NH4(+)
uptake, but carbowax restricted N03(-> uptake more than did NaCl. Under NaCl
salinity the plants absorbed the same amount of N independent of N source; under


                                       68

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water stress more NH4(+) than N03(-) was absorbed.  Water absorption was reduced
 y both stress treatments; N and water uptake were highly correlated.  Root
permeability decreased in plants subjected to stress.  Dry matter production
ana total N per plant decreased, but the N percentage increased in the stressed



78:021-029
SALT AND WATER STRESS INFLUENCES NITROGEN METABOLISM IN RED KIDNEY BEANS,
trota, J.N.E., and Tucker, T.C.
Arizona University, Tucson, Department of Soils, Water and Engineering.
soil science Society of America Journal, Vol. 42, No. 5, p 743-746, September-
October, 1978.  6 tab, 27 ref.

Descriptors:  Salinity, Moisture deficit, Nitrogen, Metabolism, Beans, Crop
production.

 oth salinity and water deficit reduce yields of crop plants.  This study was an
3"emPfc to provide a better understanding of these stress effects on N metabolism
vul   • utilization of NH4-N and NO3-N.  Red kidney bean plants (Phaseolus
in  aris L'' were grown under salt stress (NaCl) , water stress (carbowax) , and
ac-a normal nutrient solution (control).  The 15N in N03(-), NH4(+), alpha amino
m  f' total soluble-N and protein-N in plant shoots were analyzed after the
48 h   received 15(NH4)2S04 and K15NO3 in nutrient solution for 6, 12, 24, and
N* 7°urs-  Sodium chloride and carbowax . resulted in equal accumulations of N03-N,
 . _ .' f and free alpha amino acids in bean shoots.  Protein synthesis was
sal? i °antly reduced in bean shoots when the plants were subjected to NaCl
uni   tv and carbowax, with either source of N, and the inhibition was more severe
unaer salt stress than water stress.


78:021-030
AMnX«G AND RATE OF FERTILIZER NITROGEN FOR SUGARBEETS RELATED TO NITROGEN UPTAKE
AND POLLUTION POTENTIAL,
Caltl' P:J-' Broadbent, F.E. , and Fried, M.
Jo     nia University, Davis, Department of Soil Microbiology.
 ournal of Environmental Quality, Vol. 7, No. 3, p 368-372, July-September, 1978.
* f    3 tab, 11 ref.
bee£riptors :  Nitrogen, Fertilization, Timing, Nutrient requirements, Sugar
 ee«, Water pollution, Crop production, Tracers.
as"trC?en ^N'  uptake by sugarbeets (Beta vulgaris L.) from fertilizer and soil,
in ^ lated to time and rate of application, was evaluated at Davis, California,
si.° field experiments utilizing 15N-deleted ammonium sulfate.  There were no
was    Cant differences in root, top, or sugar yield when fertilizer N (135 kg/ha)
or  appliecj at planting, at thinning, split equally between thinning and layby,
suh ?    e<3ually between planting, thinning, and layby.  Also, there were no
to ^tantial differences in soil or fertilizer N in tops and roots in response
Wer   se dates of application.  Fertilizer N recovery was 47% when 112 kg N/ha
a_ e.aPPlied to achieve maximum sugar yield.  Roots removed as much N as that
tim     3nd tops contained an additional 105 kg N/ha.  When applied N was 2.5
as    the amount required for maximum sugar yield, tops and roots contained almost
 a much N as applied.  The sugarbeet crop, carefully fertilized, has potential for
 ij-eviation of nitrate pollution of groundwater.
      RELATIONS OF CADMIUM-TREATED PLANTS,
      m, M.B.
Jo,,homa Sfcate University, Stillwater, Department of Agronomy.
•> finai °f Environmental Quality, Vol. 7, No. 3, p 334-336, July-September, 1978.
*      1 tab, 21 ref.
s®?criptors:  Turgidity, Water pressure, Osmotic pressure, Cadmium, Transpiration,
 QiJ.-water-plant relationships.
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Turgor pressures, stomatal resistances, and transpiration rates were measured
during a 50-day period in leaves of chrysanthemum  (Chrysanthemum morifolium
Ramat. "Indianapolis White") plants grown in nutrient solution with 0, 0.01,
0.1, and 1.0 microgram/ml Cd added as CdS04.  At harvest, dry weight and Cd
concentrations in roots, steins, and leaves were determined.  Leaf abscission
occurred on Cd-treated plants.  Turgor pressures were highest in plants grown
with 0.01 microgram/ml Cd and lower in plants treated with 0, 0.1, and 1.0 micro-
gram/ml Cd.  Stomatal resistances were lowest in plants grown with 0.01 microgram/
ml Cd and progressively higher in plants treated with 0, 0.1, and 1.0 microgram/
ml Cd.  Results indicated that quantities of Cd permitted in irrigation water in
the United States (0.05 microgram/ml) might be detrimental to growth because of
reduced turgor pressure and increased stomatal resistance.


78:021-032
EXTRACTABILITY OF CADMIUM, COPPER, NICKEL, AND ZINC BY DOUBLE ACID VERSUS DTPA
AND PLANT CONTENT AT EXCESSIVE SOIL LEVELS,
Korcak, R.F., and Fanning, D.S.
United States Department of Agriculture, Science and Education Administration,
Fruit Laboratory, Beltsville Agricultural Research Center-West, Beltsville,
Maryland.
Journal of Environmental Quality, Vol. 7, No. 4, p 506-512, October-December, 1978.
1 fig, 9 tab, 18 ref.

Descriptors:  Trace elements, Elements (chemical), Heavy metals, Corn (field),
Sewage sludge, Correlation analysis, Cadmium, Copper, Nickel, Zinc.

Cadmium, copper, nickel, and zinc were applied as sulfate salts to samples of
surface horizons of three Maryland soils in the greenhouse at rates of metals
equivalent to those in 0 to 896 dry metric tons/ha of Washington, D.C., digested
sewage sludge.  The sludge was also applied at a rate of 224 dry metric tons/ha.
Two pH regimes, approximately 5.5 and 6.5, were maintained.  Metals were extracted
by the DTPA (diethylenetriaminepentaacetic acid buffered at pH 7.3) or double acid
(0.05N HC1, 0.025N H2S04) extractants.  Correlations were determined between
extractable soil metals and metal content of two crops of corn (Zea mays L.)
each grown for 30 days, but at times of 1 or 13 mo after making the chemical
amendments to the soils.  The results of the experiments were reported.


78:021-033
THE UPTAKE OF 203Hg-LABELED MERCURY COMPOUNDS BY BROMEGRASS FROM IRRIGATED
UNDISTURBED SOIL COLUMNS,
Hogg, T.J., Bettany, J.R., and Stewart, J.W.B.
Saskatchewan University, Saskatoon, Saskatchewan, Canada, Institute of Pedology.
Journal of Environmental Quality, Vol. 7, No. 3, p 445-450, July-September, 1978.
1 fig, 8 tab, 17 ref.

Descriptors:  Mercury, Sewage effluent. Sewage disposal, Environmental effects,
Bromegrass, Irrigation, Volatility, Leachate, Organic matter.

Bromegrass (Bromus inermis)  was grown under conditions of sewage effluent irrigation
on undisturbed soil columns in which the 0- to 10-cm layers had been treated with
10 micrograms Hg/g soil as 203Hg-labeled mercuric chloride (HgC12), phenyl
mercuric acetate (PMA), and methyl mercuric chloride (MMC).  Mercury concentra-
tions in. plant dry matter decreased over three successive harvests and highest
values were found on MMC-treated soils of fine texture and low organic matter
content (2.0 to 0.2 micrograms Hg/g for first and third harvest, respectively).
Exposure of the plants and soils to simulated fall conditions resulted in a small
but significant increase in the Hg concentration of plant dry matter.  Higher levels
of Hg were found in plant stems than plant foliage at the termination of the experi-
ment and even higher levels in the main roots and fine roots separated from the 0-10
cm soil layer.  Mercury concentration of root decreased with depth for all Hg treat-
ments, but were still 150 times greater than background levels in the MMC-treated
soils at the 40- to 60-cm depth.  A significant amount of all forms of applied
Hg (10-32%) was lost during the experiment, presumably by volatilization.  The
majority of the remaining Hg in the soil was found to be strongly bound and not
extractable by weak salt solutions, dilute acids, and chelates.
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 78:021-034
 CORN YIELD RESPONSES TO WATER STRESS  MANAGEMENT,
 Stegman,  E.G.,  and Aflatouni,  M.
 North Dakota State University,  Fargo,  Department  of  Agricultural  Engineering.
 Paper No.  78-2558, Presented at the  1978  Winter Meeting  of  the  American Society
 of  Agricultural Engineers,  December  18-20,  1978',  Palmer  House Hotel,  Chicago,
 Illinois,  9 p.   8 fig,  3 tab,  18  ref,  1 equ.

 Descriptors:  Moisture  stress,  Evapotranspiration, Crop  response,  Corn  (field),
 Moisture  deficit,  Growth stages,  Irrigation, Water management  (applied), Water
 requirements, Irrigation systems.

 Relative   yield (Y/Ymax)  vs.  relative  evapotranspiration (ET/ETmax) functions were
 defined  for major growth periods.  These  functions also  suggested  some  yield loss
 may occur due to water  stress  before  an ET  depression  necessarily  also  occurs.
 Relative  yield  attainment was  also related  to minimum  levels of leaf  xylem pressure
 just prior to stress relief in given  growth stages.


 78:021-035
 PREDICTING YIELDS,
 Haun,  J.R.
 Clemson University,  South Carolina, Department  of Horticulture.
 Crops  and  Soils Magazine, Vol.  31, No. 2, p 7-9,  November,  1978.   3 fig.

 Descriptors:  Crop production,  Crop response, Climatic data, Weather  data, Plant
 growth.

 This paper presents  a new concept in  the  evaluation  of plant-environment relations
 for developing  yield prediction systems.  This  approach  involves the  daily mea-
 surement  of plant response  in  the field under natural, uncontrolled variations
 in  weather conditions.   These  plant growth  data,  with associated weather variables,
 are to be  analyzed by computer  to develop the yield  prediction  system.


 78:021-036
 SOYBEAN CROP WATER REQUIREMENTS,
 Dominguez,  J.,  Horta, M. , and  Robledo, E.
 Regional Center of Agricultural Research  No. 06,  CRIDA 06,  Spain,  Department of
 Cereals and Legumes .
 ICID Bulletin,  Vol.  27,  No.  2,  p 30-35, July, 1978.  3 fig, 22  ref.

 Descriptors:  Soil-water-plant  relationships, Water  requirements,  Soybeans,
 Moisture deficit,  Moisture  stress, Growth stages, Water management (applied),
 Evapotranspiration,  Yield equations, Crop production.

 In  experiments  carried  out  in  the three-year period  1974-1976,  in  "Pinca El Encin",
 CRIDA  06,  Alcala de  Henares, on soybean crops irrigated by  sprinklers, Amsoy
 variety, a very high correlation between  the RET  (Real Evapotranspiration)  in the
 flowering  and pod  formation period and the  final  grain production was found.  This
 suggested,  on the  one hand, subjecting the  plant  to  an initial deficit to adequately
 develop the root system and on  the other, ': supply ing  quantities of  about 9 mm during
 the  said period, which  should increase the  production level to  4,000 kg/hectare.
 Penman's modified  formula for daily application,  following  the guidelines of the
 Irrigation  Management Service,  proved to be inadequate in the sense that it pro-
 vided  low  ETP values.   A greater consideration  of the aerodynamic  term was suggested
 by  the influence that the advective effect  has  on irrigation areas. with arid cli-
 mates.  For practical experiments the scheme proposed in the DWR-UCD Meeting 1975
 based, on the utilization of the distribution curves  of a water sprinkler, was
 proved satisfactory, leading to a more reliable analysis, and to a simplification
 of  the experimental  procedure.


 78:021-037
WATER  BALANCE OF FLOODED RICE PADDIES,
Brown, K.W., Turner,. F.T., Thomas, J,C,,  Deuel,  L,E,, a.nd Keener.  M.E.
 iexas ASM University,  College Station,  Department o? Soil and Crop  Sciences,
     "       ""^ Manaement  Vo1'  1  No- 3    2-
                                                                             ,
3 tab"       ""^ Management'  Vo1'  1'  No-  3'  P 277-291,  November,  1978.   10  fig,
                                      71

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 Descriptors:   Water balance,  Submerged plants,  Flood irrigation.  Rice,  Water
 management (applied),  Water requirements,  Evapotranspiration,  Runoff.
                                                        2
 Rice (Oryza sativa L.,  var.  Labelle)  was  grown  in 300 m  paddies  of Beaumont clay
 soil (Typic pelludert)  and subjected  to two management schemes of flooded  rice
 culture.   These schemes were continuous irrigation and intermittent irrigation.
 Careful measurements of irrigation, precipitation,  evapotranspiration,  deep
 percolation and runoff were made,  and the total water balance  for the two  water
 management schemes was calculated.  The results showed continuous irrigation to
 be  very wasteful of water  with slightly over 1  m of irrigation water applied to
 supply an evapotranspirational need of 0.5—0.6 m.   The intermittent irrigation
 management was less wasteful but still could be improved  upon.  Suggestions  were
 presented for techniques to help improve  the water use efficiency and reduce
 runoff losses.


 78:021-038
 SEASONAL  WATER USE BY  WINTER WHEAT GROWN  UNDER  SHALLOW WATER TABLE CONDITIONS,
 Saini, B.C.,  and Ghildyal,  B.P.
 G.B.  Pant University of Agriculture and Technology,  Pantnagar,  Distr. Nainital,
 India.
 Agricultural  Water Management,  Vol. 1,  No.  3, p 263-276,  November,  1978.   10 fig,
 1 tab, 27 ref.
 (See 78:02G-076)


 78:021-039
 LEAF OSMOTIC  POTENTIAL  AS  AN INDICATOR OF  CROP  WATER DEFICIT AND  IRRIGATION  NEED
 IN  RAPESEED (BRASSICA  NAPUS  L.),
 Clarke, J.M.,  and Simpson,  G.M.
 Research  Station,  Research Branch, Agriculture  Canada,  Swift Current, Saskatchewan
 S9H 3X2,  Canada.
 Agricultural  Water Management,  Vol. 1,  No.  4, p 351-356,  December,  1978.   2  fig,
 3 tab, 8  ref.

 Descriptors:   Moisture  deficit, Moisture  content, Water requirements, Moisture
 stress, Moisture tension,  Leaves,  Scheduling, Tensiometers,  Osmotic  pressure,
 Crop production.

 Leaf osmotic  potentials (LOP)  of field-grown rapeseed  (Brassica napus L.) were
 measured  in 1975 and 1976  under rainfed conditions  and  at two  levels of irrigation.
 Irrigations were scheduled on the  basis of  tensiometer  measurements  in  1975,  and
 on  the basis  of  LOP  in  1976.   The  LOP of rainfed plants was  lower  (more negative)
 than that of  irrigated  plants.  Leaf osmotic potential  responded  to  changes  in
 soil  moisture  caused by precipitation or irrigation.  Tensiometers placed at 0.2
 m depth in the high  irrigation treatment were as responsive  to  soil moisture
 changes as LOP.   Scheduling of irrigations  on the basis of LOP  in  1976 produced
 yield differences  between water regimes similar to  those obtained  in 1975.   It
 was concluded  that leaf osmotic potential provides  a satisfactory means for
 determining need for irrigation in B. napus.


 78:021-040
 RESPONSE  TO CORN TO LIMITED IRRIGATION  ON SANDY SOILS,
Wilson, G.D., Watts, D.G.,  and Fischbach,  P.E.
Nebraska  University, North Platte,  Department of Agricultural Engineering.
Paper No.   78-2554, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers,  December 18-20,  1978, Palmer House Hotel, Chicago,
Illinois,   11 p.  6 fig,  5 tab, 3 ref,  1 equ, 3 append.

Descriptors:  Irrigation, Moisture deficit,  Irrigation  effects, Water management
 (applied), Growth stages, Plant populations, Yield equations, Corn  (field),
Water requirements, Crop production.

The objective of this experiment was to provide information for producers to enable
them to make sound decisions concerning irrigation management when water is  limited.
Five irrigation management systems  were evaluated on a Valentine very fine sand
 (Typic Ustipsamment) in North Central  Nebraska in 1977 and 1978.  Two management
systems included limited irrigation.   The latter were subdivided into three treat-
ments each in 1977 providing a total of six discrete limited irrigation treatments.

                                      72

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 Another treatment was added in 1978 making a total of seven limited irrigation
 treatments.  In each year, the limited irrigation treatments were compared to
 nonirrigated and fully irrigated checks.  Significant water savings were achieved
 with the limited irrigation treatments.  Yield variation from full irrigation
 yields ranged from 4750 kg/ha reductions to 900 kg/ha increases.  As much as
 12.2 cm of irrigation water were saved with no yield reduction, even though water
 use was reduced.  Irrigation response ratio was defined as the yield increase
 over the nonirrigated crop per unit of water applied.  It was presented as a
 management tool and was significantly affected by limited irrigation.


 78:021-041
 EVALUATION OF CROP WATER STRESS UNDER LIMITED IRRIGATION,
 Heermann, D., and Duke, H.
 Agricultural Research, Science and Education Administration,  Fort Collins,
 Colorado, United States Department of Agriculture.
 Paper No. 78-2556, Presented at the 1978 Winter Meeting of the American Society
 °f Agricultural Engineers, December 18-20,  1978, Palmer House Hotel, Chicago,
 Illinois, 5 p.   8 fig, 8 ref.

 Descriptors;   Moisture stress. Moisture deficit, Sprinkler irrigation,  Soil
 moisture, Yield equations, Corn (field),  Growth stages,  Water requirements.

 Limited water application plots were established under 2 center pivot systems
 Planted to corn.   Stress was quantified by  measuring water applied,  soil water,
 canopy temperatures and plant  water potentials.   Yield reductions were  linearly
 related to applied water and average canopy temperature  differences between  control
 and stressed  plots.


 78:021-042
 IRRIGATED CORN YIELD RESPONSE  TO WATER,
 Musick, J.T., and Dusek, D.A.
 southwestern Great Plains  Research Center, Bushland, Texas, United States Department

 Paper No. 78-2557, Presented at the  1978 Winter Meeting of the American Society of
 Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago, Illinois
 **> p.   8 fig, 3 tab, 16 ref.                                                       '

 Descriptors:  Irrigation,  Crop response, Moisture deficit, Evapotranspiration,
 Moisture stress, Corn  (field), Water requirements. Yield equations, Growth stages
 water management (applied).

 Corn grain yield response to water deficits and seasonal evapotranspiration-yield
 relationships were determined during a 3-yr study in the Southern High  Plains.
 sensitivity of yields and water-use efficiencies to plant-water stress  indicated
 tnat limited irrigation should not be practiced in the high-evaporative  demand
climate.


 78:021-043
 MAGNESIUM UPTAKE FROM EXCHANGEABLE AND NONEXCHANGEABLE SOURCES IN SOILS AS MEASURED
 BY INTENSIVE CROPPING,
 Christenson, D.R., and Doll, E.G.
 Michigan State University, East Lansing, Department of Crop and Soil Sciences.
 Soil Science, Vol. 126, No. 3, p 166-168, September, 1978.  4 tab, 6 ref.

 Descriptors:  Magnesium, Nutrients, Minerology, Greenhouses, Nutrient removal,
 °ats, Michigan, Plant growth.

 Several soils were cropped with four consecutive crops of oats (Avena sativa,
 Garry") in the greenhouse.  Changes in exchangeable Mg levels were used to indi-
 cate uptake from that source.   The remainder of the uptake was attributed to the
 nonexchangeable source.  Total uptake by the four crops did not appear  to be
 related to total Mg level in the soil, percent clay in the soil, or exchangeable
Mg level.  Mg availability did appear to be related to the mineralogy of the
medium clay fraction.
                                      73

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                                      SECTION  X

                                    WATER CYCLE

                       EROSION AND SEDIMENTATION  (GROUP 02J)


78:02J-001
A SIMPLE LABORATORY APPARATUS TO MEASURE RELATIVE ERODIBILITY OF SOILS,
Chandra, S., and De, S.K.
Allahabad University, India.
Soil Science, Vol. 125, No. 2, p 115-121, February, 1978.   3 fig, 3 tab,' 18 ref.

Descriptors:  *Erosion rates, *Measurement, *Erosion, *Erodibility, Soils,
Laboratory  equipment, Laboratory tests, Clays, Soil conservation. Instrumentation.

A simple laboratory apparatus designed for rapid and inexpensive measurement of
the relative erodibility of soils was described.  Erosion coefficients obtained
with this apparatus were correlated with other erosion indices, viz., erosion
ratio, clay ratio, and silicarsesquioxide ratio, and were found to be in good
agreement.  This apparatus can be used where routine analysis is required of a
large number of soil samples for their relative erodibility by water.


78:02J-002
EROSION RATES OF COHESIVE SOILS,
Ariathurai, R., and Arulanandan, K.
Nielsen Engineering and Research, Incorporated, Mountain View, California.
Journal of  the Hydraulics Division, Proceedings of the American Society of Civil
Engineers,  Vol. 104, No. HY2, Technical Notes, p 279-283, February, 1978.  5 fig,
4 ref, 1 append.

Descriptors:  *Erosion rates, *Cohesive soils, *Laboratory tests. Erosion, Soils,
Shear stress, Clays, Soil types, Cation exchange, Loam, Illitie, Temperature,
Chemical properties, Mechanical properties, Expansive soils, Testing procedures,
Yolo loam.  Sodium adsorption ratio.

The objective was to describe the effects of the principal physical and chemical
factors on  the rate of erosion of saturated cohesive soils.  A number of remolded
samples with different types and amounts of clay and different pore fluid composi-
tions were  preconsolidated in a 7.6-cm diam cylindrical tube at a normal stress of
1 kg/sq cm.  After consolidation, the samples were placed in the eroding fluid
to be used  and were allowed to swell for a few hours.  The results of erosion
tests on over 200 natural and made-up soil samples indicated that the erosion
rate constant M lies in the range 0.003 g/sq cm x min to 0.03 g/sq cm x'min with
few exceptions.  The slopes of the erosion rate curves increases,.with increase
in critical shear stress.  If the relationship between s and critical shear stress
were inverse, then M would be independent of the critical shear stress, although
N may vary with other*chemical and physical parameters.  If further measurements
designed to investigate the relationship between the erodibility constants criti-
cal shear stress and M should yield a functional relationship between the two,
there will be one less parameter to deal with in problems such as the determina-
tion of soil yield from watersheds, and estuarial sediment transport.


78:02J-003
PHYSICAL, CHEMICAL, AND MINERALOGICAL PROPERTIES OF FLUVIAL UNCONSOLIDATED BOTTOM
SEDIMENTS IN NORTHWESTERN OHIO,
Wall, G.J., Wilding, L.P., and Smeck, N.E.
Guelph University, Ontario, Canada NIG 2W1, Agricultural Canada.
Journal of  Environmental Quality, Vol. 7, No.  3, p 319-325, July-September, 1978.
5 fig, 5 tab, 16 ref.

Descriptors:  Fluvial sediments, Unconsolidated sediments, Chemical properties,
Physical properties, Minerology, Water pollution, Water quality, Heavy metals,
Sediment load, Suspended load.
                                      74

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Fluvial unconsolidated bottom sediments that have the potential to become part of
the suspended sediment load in the Maumee River Basin, Ohio, ranged in texture from
sandy loams to' clays.  The water-dispersible clay was lower in mica but higher in
expandable 14 A  (smectite) and quartz constituents than the electrolyte-dispersible
clay.  The mineralogy of clay-sized bottom sediments from upstream agricultural
drainage ditches, major Basin tributaries, and from the Maumee River were found to
be essentially identical.  The 2- to 50-microns fraction was dominated by quartz
with secondary amounts of mico, kaolinite, feldspars, and carbonates.  Mean
calcite, dolomite, and calcium carbonate equivalent values were 4.1, 3.4, and 7.8%,
respectively.  Organic matter content of the fluvial bottom sediments (3 to 7%)
was analogous to Lake Erie bottom sediments and Maumee River suspended sediments.
CEC values ranged from 39 to 55 meq/100 g for the total clay fraction.  Enrichment
of heavy metals of bottom sediments over surficial soil materials occurred for Cu,
Ni, Zn, Ca, and Pb by factors of 1.6, 2.0, 2.3, 3.5, and 3.0, respectively.  Traces
of herbicides and insecticides were detected in the filtered stream water samples
and bottom sediment materials.  Downstream trends in selected physical,  chemical,
and mineralogical properties could not be related to increased urban influences or
increased stream discharge.


78:02J-004
UNIT SEDIMENT GRAPH,
Rendon-Herrero, O.
Mississippi State University, Starkville, Department of Civil Engineering.
Water Resources Research, Vol. 14, No. 5, p 889-901, October, 1978.  12  fig, 3 tab,
23 ref, 3 equ.

Descriptors:  Sediment discharge, Suspended load, Unit hydrographs, Graphical
analysis, Graphical methods, Small watersheds, Surface runoff, Soil erosion,
Precipitation (atmospheric).

The unit hydrograph method was extended to sediment graph analysis, thus yielding  '
a unit sediment graph.  The method is applicable to small uniform watersheds where
the main contribution to suspended sediment transported in the drainage  channels as
the result of runoff derives from upslope erosion, that is, from wash load and not
from entrained bed load material.  Bixler Run, a small wash load-producing water-
shed near Loysville, Pennsylvania, was used as a data source in deriving unit
sediment graphs.  The hydrographs and concomitant sediment graphs used were
generally parallel in shape and coincided during peak flow.


78:02J-005
DEPOSITION OF NONUNIFORM SEDIMENT ON CONCAVE SLOPES,
Davis, S.S., Foster, G.R., and Huggins, L.F.            _        ...
Purdue University, Lafayette, Indiana, Department of Agricultural Engineering.
Paper No. 78-2519, Presented at.the 1978 Winter Meeting of the American  Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 19 p.  8 fig, 4 tab, 20 ref, 3 equ.

Descriptors:  Sediment transport, Simulation analysis, Overland flow, Aggregates,
Sands, Sediment yield, Homogeneity, Heterogeneity, Slopes, Watersheds (basins).

A laboratory study was conducted to investigate behavior of simulated natural
sediments transported and deposited by overland flow.  Aggregate substitutes and
sand were studied both as separate homogeneous-sediments and as weight proportionally
combined heterogeneous sediment mixtures.


78:02J-006
DESIGN AND OPERATION OF GRADIENT TERRACE SYSTEMS,
Bondurant, D.T., and Laflen, J.M.
Soil Conservation Service, Des Moines, Iowa.
Paper No. 78-2520, Presented at the 1978 Winter Meeting of the American  Society
°f Agricultural Engineers, December- 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 7 p.  4 fig, 5 tab, 19 ref.

Descriptors:  Terracing, Erosion control, Pollution abatement, Design criteria,
Costs, Water quality, Graded, Soil conservation, Water conservation, Sediment
control.


                                      75

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Two types of gradient terraces were planned on each of two Iowa fields.  Comparison
shows that the type of terrace selected will have a major effect on cost of
terracing and on farmer acceptance, but little effect on off-field water quality.


78:02J-007
EXCAVATED SEDIMENT TRAPS—WHAT RALPH WALDO EMERSON WAS REALLY TALKING ABOUT,
Tryon, C.P., Parsons, B.L., and Miller, M.R.
Mark Twain National Forest, Rolla, Missouri.
Paper No. 78-2089, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 10 p.  9 ref.

Descriptors:  Sediment control, Sediments, Sediment load, Soil erosion, Detention
reservoirs, Erosion, Cost comparisons, Comparative costs, Missouri.

A decade of experience on large earth moving jobs in the Missouri Ozarks has
shown that excavated sediment traps are incomparably superior to small detention
dams in terms of cost, industry acceptance, and sediment trap efficiency.


78:02J-008
REDUCING STREAM SEDIMENT LOADS BY IRRIGATION DIVERSIONS,
Johnson, C.W., and Smith, J.P.
Northwest Watershed Research Center, Boise, Idaho,
Paper No. 78-2088, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 14 p.  4 fig, 4 tab,
11 ref.

Descriptors:  Sediment control, Sediment load, Sediment discharge, Soil erosion,
Sediments, Streamflow, Diversion, Diversion structures, Irrigation, Idaho.

A streamflow, irrigation diversion, and suspended sediment study on the Reynolds
Creek Experimental Watershed in southwest Idaho shows the effectiveness of an
irrigation system in reducing downstream sediment loads.  About 560 tonnes of
sediment per year was deposited on 690 ha of pasture, hay, and grain cropland,
an average deposition of 0.08 mm per year.  The sediment from natural streamflow
is usually beneficial to crop production in this mountain valley.


78:02J-009
THE DESIGN OF SEDIMENT BASINS,
Ward, A.D., Haan, C.T., and Barfield, B.J.
Kentucky University, Lexington, Department of Agricultural Engineering.
Paper No. 78-2086, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 32 p..  4 fig, 4 tab,
17 ref, 15 egu.

Descriptors:  Sediment control, Sediments, Detention reservoirs, Design, Mining,
Mine wastes, Hydrologic aspects, Regression analysis, Simulation analysis,
Computer programs.

Passage of Public Law 95-87 has placed several new restrictions on the design of
surface mine sediment basins.  It created much controversy as to the required
sizing of the sediment basins, and adequate design methods are not available for
estimating basin performance and effluent sediment concentrations.  This paper
presents guidelines as to how the hydrologic parameters affecting sediment basin
design may be quantified and contains predictive equations for estimating' basin
trap efficiency and peak effluent sediment concentrations.  Multiple regression
analysis techniques were employed with data generated by a hydrograph computer
program and by a simulation model.  The simulation model has been tested on several
actual basins and appears to give a good estimate of basin performance.  It also
gave a good estimate of the performance of Callahan Reservoir during a 60-day
period in 1973.  A new version of the model allows for variation in the particle
size distribution with runoff rate, and in this paper criteria are presented which
account for basins with a permanent pool and also considers base flow conditions
following a design storm event.
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 78:02J-010
 SEDROUTE PROCEDURE FOR ESTIMATING EROSION AND SEDIMENT IMPACTS,
 Kelly, G.D.
 Manti-LaSal National Forest, Price, Utah.
 Paper No. 78-2081, Presented at  the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June  27-30, 1978, Logan, Utah, 7 p.  4 ref, 3 equ.

 Descriptors:  Sediment yield, Surface runoff, Runoff, Sediments, Model studies,
 Sediment load, Data processing,  Mining, Sediment control, Idaho.

 The SEDROUTE procedure predicts  the amount and charge in erosion and sediment
 yield that will occur from a proposed project.  The model uses a minimum of data
 and responds to changing project details.  Impacts are routed downstream to show
 the effects of other water and sediment sources.


 78:02J-011
 SEA RESEARCH PROGRAM FOR CHANNEL STABILITY AND GULLY CONTROL,
 Little, W.C., Piest, R.F., and Robinson, A.R.
 Paper No. 78-2080, Presented at  the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June  27-30, 1978, Logan, Utah, 18 p.  13 ref.

 Descriptors:  Channel erosion. Channel improvement, Stability, Gullies, Gully
 erosion, Stream erosion, Stabilization, Research and development. Environmental
 effects.

 There are a multitude of factors relating to problems of unstable channels and
 active gullies.  There are limited methods of control and additional cost
 effective methods are required.  The potential for improved technology is great.
 The USDA, Science and Education  Administration, Federal Research Program is
 conducting research on stabilization of stream channels and control of gullies.


 78:02J-012
 EROSION SIMULATION FOR LAND USE MANAGEMENT,
 DeCoursey, D.G.
 Sedimentation Laboratory, Oxford, Mississippi, U.S. Department of Agriculture.
 Paper No. 78-2Q82, Presented at  the 1978 Summer Meeting of the'American Society
 of Agricultural Engineers, June  27-30, 1978, Logan, Utah, 18 p.  6 fig, 8 tab.

 Descriptors:  Soil erosion, Erosion, Simulation analysis, Runoff, Surface runoff,
 Sediment yield, Hydrographs, Land management, Land use, Cotton.

 In May, 1976, a paper entitled "Philosophy of Erosion Simulation for Land Use
 Management" by D.G. DeCoursey and L.D, Meyer was presented at a Soil Erosion
Workshop at Purdue University.   The paper described schematically, a concept for
 combining hydrology, infiltration, moisture redistribution,  crop growth, and
 rill-interrill erosion models to produce a dynamic simulation system that can be
 assembled to evaluate the environmental impact of land management alternatives.
Most of the parameters are based on measurable factors or field tests.  This
Paper describes such a simulation system and the data necessary to use it.  Data
 from a cotton field in the Mississippi Delta were used to test and refine the
 system.  Examples showing how the system can be used to evaluate alternative
 land management schemes, are presented.  Output from the system includes runoff,
 sediment, and cotton production.   They were used to show how factors such as
Plant population fertilizer, row spacing, land slope and tillage operations can
affect management alternatives.


 78:02J-013
TOTAL LOAD OF BED MATERIALS IN OPEN CHANNELS,
Kikkawa,  H., and Ishikawa,  T.
Tokyo Institute of Technology, Japan,  Department of Civil Engineering.
Journal of the Hydraulics Division,  American Society of Civil Engineers,  Vol.  104,
No.  HY7,  Proceedings Paper 13895, p 1045-1059,  July, 1978.   10 fig,  12 ref, 2
append.

Descriptors:  *Bed load,  *Open channels,  *Model studies,  *Stochastic models,
Channel flow,  Sediment transport, Stochastic processes,  Suspended load,  Hydraulics,
Sedimentation,  Equations, Mathematical models,  Bed material  load,  Sediment sources,
Synthetic models.

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Bed material  load usually  is  classified  into bed  load and suspended  load.  They
have been  treated individually  in  the previous theoretical studies,  but to obtain
the expression of total  load, their mutual relation must be  formulated.  The main
objective  in  this investigation was to study this relation.  The basic consideration
was that the  bed layer is  formed under the balance of vertical  forces acting on
sediment particles near  and on  the bed surface.and this layer can be regarded as
the source of sediments  to be diffused to the region of suspended load.  According
to this consideration:   (1) a new  stochastic model that interrelates bed load
and suspended load was considered  to simulate the particle movement; and (2) the
equation of dynamic balance in  the bed layer was introduced  and improved by using
the results of basic experiments.  A total load equation was derived by combining
the results of two processes.   The data  presented by U.S.G.S. were used to verify
it.


78:02J-014
DIFFUSION OF  SEDIMENT IN LONG CHANNELS,
Aronsson, G.
Uppsala University, Sweden, Department of Mathematics.
Journal of the Hydraulics  Division, American Society of Civil Engineers, Vol. 104,
No. HY6, Proceedings Paper 13845,  p 821-837, June, 1978.  7  fig, 12  ref, 1 append.

Descriptors:  *Dispersion, *Diffusion, *Sediments, *Model studies, *Long channels,
Mathematical  models, Distribution, Distribution patterns, Sediment distribution.
Spatial distribution, Channels, Turbulence, Sediment transport, Sedimentation,
Mathematics.

A model was presented, treating the transport of suspended material  in a broad
channel under simplifying  assumptions.   The motion of sediment was treated as a
diffusion process, and a differential equation was derived.  The form of an
"equilibrium  distribution" g(y)  was derived, corresponding to the classical distri-
bution of Prandtl and Rouse.  Mathematically the following two results were
proven:  (1)  if a stationary  (time dependent) state prevails downstream at a certain
point P, then the distribution downstream P tends (with increasing distance to
P) exponentially to the "equilibrium distribution"; and (2)   if the sediment dis-
tribution in  the incoming  downstream P will tend to the stationary solution ex-
ponentially with time.  Although these results seem to be physically evident, they
apparently have not been proven before.


78:02J-015
EROSION CONTROL/SEDIMENT MODELING—SOUTHERN IDAHO A PROGRESS REPORT,
Longley, T.S.
Idaho University, Aberdeen, Research and Extension Center.
Paper No. 78-2028, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 6 p.   3 fig, 4 ref,
12 egu.

Descriptors:  Soil erosion, Erosion, Agricultural watersheds, Sediments, Sediment
load, Return flow, Idaho,  Irrigation,  Water quality,  Model studies.

The progress of erosion control/sediment modeling was reported.   The modeling
effort proceeded in three  steps:   (1)  the furrow erosion submodel, (2)  the instream
erosion control practice submodel, and (3)  the routing method to route the water
down through the watershed.  The furrow erosion submodel predicts the sediment
lost from an individual field using furrow hydraulic parameters  and  the stream power
concept explained below.    The instream erosion control practice submodel predicts
the effectiveness of the best management practices in cleaning the sediment from
the return flow, and finally a routing procedure is used to move the flow and
associated sediment through the watershed.


78:02J-016
SCOUR OF BED MATERIAL IN VERY ROUGH CHANNELS,
Bayazit, M.
Technical University, Istanbul,  Turkey, Department of Hydraulics and Water Power.
Journal of the Hydraulics  Division, American Society  of Civil Engineers,  Vol.  104,
No. HY9, p 1345-1349, September, 1978.  3 fig,  2 ref, 4 equ,  1  append.



                                      78

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 Descriptors:  Scour, Open channel flow, Roughness (hydraulic), Beds, Velocity, Flow
 characteristics, Vibrations.

 In this paper an attempt was made to explain the relative roughness effect on the
 scour of bed material in shallow depths on the basis of flow characteristics ob-
 served in a previous study (Bayazit, J. of Hydraulic Res., 14(2), 1976).  Experi-
 ments with densely packed uniform spheres confirmed that the initiation of motion
 of bed material is affected by the relative roughness of the channel.  At shallow
 depths, larger values of the Shields' parameter are required to initiate the motion.
 This was explained by the reduction of nondimensional velocities at the bed level
 with the increase of relative roughness.  The effective value of the instantaneous
 flow velocity was thus achieved at higher bed shear stresses in comparison with
 flows at mild slopes.


 78:02J-017
 NUMERICAL STUDY OF CONTINUOUS SALTATION,
 Reizes, J.A.
 New South Wales University, Sydney,  Australia,  School of Mechanical and
 Industrial Engineering.
 Journal of the Hydraulics Division,  American Society of Civil Engineers, Vol.  104,
 No. HY9, p 1305-1321, September, 1978.   12 fig, 15 ref, 31 egu,  3 append.

 Descriptors:  Saltation, Sediment transport, Numerical analysis,  Mathematical
 models, Computer programs,  Bed load, Simulation analysis,  Drag.

 This paper reported a theoretical study of a particle in continuous saltation
 involving a numerical solution of the three-dimensional equations of particle
 motion including collision  with the  bed.  Some  of  the difficulties and  inaccuracies
 associated with an experimental evaluation of bed  load were avoided by  the use of
 a  computer simulation of a  saltating particle.   Continuous saltation was possible
 as the result of the proposed three-dimensional bed-particle interactions,  even
 in the absence of vertical  fluid velocity component's and lift forces.   Comparison
 with experimental data suggested that the model is at least a reasonable represen-
 tation of the process.   It  was shown that for an isolated  particle near the bed,
 an apparent lift force,  which can be greater than  the gravitational force,  results
 from the nonlinear drag  force.   It was  also shown  in this  study that previously
 attempted single parameter  correlations are inadequate and that at least two
 Parameters are required  to  collapse  the numerical  results  into an orderly array
 of curves.   The  Shields  entrainment  function and the particle Reynolds  number were
 modified to obtain two parameter correlations.


 ?8:02J-018
 TRANSPORT OF  A NONCOHESIVE  SANDY- MIXTURE IN RAINFALL AND RUNOFF EXPERIMENTS,
 Walker,  P.H.,  Kinnell, P.I.A.,  and Green,  P.
 Sediment  Transport Group, Division of Soils,  Box 639,  P.O.  Canberra  City, A.C.T.
 2601,  Australia.
 Soil  Science  Society of  America  Journal, Vol. 42, No.  5, p  793-801,  September-
 October,  1978.   8  fig, 3  tab,  20  ref, 4  equ.

 Descriptors:   Raindrops,  Runoff,  Surface runoff, Suspension,  Rainfall intensity,
 Bed  load,  Suspended  load, Overland flow, Soil erosion.

 Rainfall  intensities  of  45, 100,  and 150 mm/hr with  systematically varied kinetic
 energies were  applied to  a saturated noncohesive, sandy bed 3 m long and set at
 slopes of  0.5  and  5%.  Detailed size analyses of solids discharged showed that the
 *31 micron  fraction was most readily mobilized and behaved as a suspended load;
 and  31- to  250-micron fraction was transported slowly, much apparently as saltating
 bed  load; the  0.25- to 4-mm fraction was transported rapidly, grains tending to
move as rolling bed load; the >4 mm fraction behaved as a lag gravel.  The sedi-
mentary properties of bed deposits also reflected the differentiation of various
 size fractions and minerals in the original mixture.  The effects of raindrop im-
Pacts within the flow were more important in promoting transport of solids than
 the aerial component of splash.  Under conditions where overland flow had
developed, transport of solids was related directly to rainfall intensity and
variations in rainfall energy that were associated with variations in raindrop
 impact frequency.  Increases in rainfall energy due to increasing raindrop sizes
    not result in increases in solids discharged.


                                      79

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78:02J-019
SUBSURFACE DRAINAGE MODEL WITH ASSOCIATED SEDIMENT TRANSPORT,
Bottcher, A.B., Monke, E.J., and Huggins, L.F.
Florida University, Gainesville.
Paper No. 78-2502, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 21 p.  4 fig, 15 ref, 18 equ.

Descriptors:  Subsurface drainage, Model studies, Computer models, Sediment
transport. Simulation analysis. Tile drainage, Water yield, Sediment yield,
Flow rates. Hydraulic conductivity.

A computer model was developed, using the GASP IV simulation language to simulate
the water flow and sediment movement from a subsurface drainage system.  The model
uses a one dimensional form of the Richard's Equation and a steady state tile flow
formula by Toskoz and Kirkham to express the water movement process.  The particle
detachment model, which is based on a force balance relationship, is driven directly
by the output of the flow model.  Data required by the model includes rainfall,
evapotranspiration, soil properties, and the drainage system layout.  Calibration
and verification was completed using data collected from a seventeen hectare tile
drainage system located on a flat Hoytville silty clay soil.  A comparison of the
simulated and observed results indicate that the model will reliably predict
water yield, sediment yield and the sediment concentration curve.  The model had
difficulty in simulating the actual shape of the flow hydrograph.


78:02J-020
FARM LEVEL ECONOMIC EVALUATION OF EROSION CONTROL,
McGrann, J.M.
Iowa State University, Ames.
Paper No. 78-2515, Presented at the 1978 Winter Meeting of the American Society of
Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago, Illinois,
13 p.  2 fig, 3 tab, 15 ref.

Descriptors:  Erosion control, Soil erosion, Cost comparisons, Soil management,
Economic feasibility, Water pollution, Economic impact, Contour farming.

Farm level economic evaluation of erosion control alternatives in three major
soil associations in Iowa indicated that:  (1) residue tillage and contouring is
the most cost effective alternative to reduce soil erosion, (2) the economic impact
of reducing soil loss is less on mixed crop and livestock farms than specialized
crop farms, and C3) although the economic impact of erosion control differs between
soil areas, reduction of soil loss below the 5 ton level can be accomplished through
conservation tillage in large areas of Iowa with little reduction in farm income
without public participation in farm level costs.


78:02J-021
EROSION INVENTORY-SHEET AND RILL EROSION,
Dideriksen, R.I., and Hidlebaugh, A.R.
Soil Conservation Service, Washington, District of Columbia.
Paper No. 78-2514, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 33 p.  3 fig, 14 tab, 13 ref.

Descriptors:  Erosion, Soil erosion, Rill erosion. Sheet erosion, Wind erosion,
Erosion control, Data collections, Conservation.

Erosion by wind and water from farmland remains a serious problem in the United
States.  This inventory takes a new look at the problem and provides current
information on natural and related resources on nonfederal land for all states
except Alaska.  Nearly one quarter million randomly selected sample sites were
observed in the field and farm owners and operators were interviewed.  The data
gathered in 1977 were used in the Universal Soil Loss and Wind Erosion models
to estimate the rate and amount of sheet, rill, and wind erosion for different
soils,  land uses, and management systems.
                                      80

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 78:02J-022
 EVALUATION OF GRASS CHARACTERISTICS RELATED TO SEDIMENT FILTRATION,
 Hayes, j.c., Barfield, B.J., and Barnhisel, R.I.
 Kentucky University, Lexington, Department of Agricultural Engineering.
 Paper No. 78-2513, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago
 Illinois, 21 p.  7 fig, 2 tab, 10 ref.

 Descriptors:  Sediment transport. Sediment control, Filtration, Grasses, Vegetation
 effects, Sediment yield. Water pollution, Regression analysis, Rouahness coeffi-
 cient, Watershed management.                '                      '

 Vegetal filtration was proposed as a means of reducing sediment from disturbed
 areas.  Recent studies using simulated media have led to relationships which
 define deposition within a grass filter.  Several characteristic dimensions were
 required to define the effects of vegetation on flow and sediment transport.
 Quantification of these dimensions, sensitivity of the relations to errors in
 measurement,  and further verification data was included in the paper.


 78:02J-023
 NITROGEN AND PHOSPHORUS LOSSES IN RUNOFF FROM NO-TILL SOYBEANS,
 McDowell, L.L., Ryan,  M.E., McGregor,  K.C.,  and Greer,  J.D.
 Sedimentation Laboratory,  Oxford, Mississippi, United States Department of
 Agriculture.
 Paper No. 78-2508,  Presented at the 1978 Winter Meeting of the American Society
 °f Agricultural Engineers,  December 18-20, 1978,  Palmer House Hotel,  Chicago,
 Illinois, 8 p.   10  fig, 4  tab, 18 ref.
 (See 78:05G-043)


 78:Q2J-024
 A  FINITE  ELEMENT  HYDROLOGIC MODEL TO DETERMINE THE  EFFECT  OF  LAND MANAGEMENT
 PRACTICES ON  EROSION AND SEDIMENTATION IN A WATERSHED,
 Ross,  B.B., Shanholtz,  V.O.,  and  Contractor, D.N.
 Virginia  Polytechnic Institute and State University, Blacksburq, Department  of
 Civil  Engineering.
 Paper  No. 78-2507, Presented at the 1978 Winter Meeting of the  American Society of
 Agricultural  Engineers, December  18-20,  1978,  Palmer House Hotel, Chicago,
 Illinois, 42  p.   11 fig, 7  tab, 41 ref,  12 equ.

 Descriptors:  Soil erosion,  Sedimentation, Sediment transport,  Erosion, Land
 management, Flood routing,  Finite  element analysis, Water  quality, Simulation
 analysis, Model studies.

 The use of a  finite element  flood  routing model for simulating  erosion and sediment
 transport was proposed.  A  conceptual  framework was provided whereby detailed
 spatiotemporal variations in  such  factors as soils, landuse topography and rainfall
 can be integrated to predict water  quantity and quality to determine the effect
 °f various landuse management practices  on erosion and sediment transport.


 78:02J-025
 SEDIMENT SIZES ERODED FROM ROWCROP  SIDESLOPES,
 "eyer, L.D., Harmon, W.C., and McDowell, L.L.
 Sedimentation Laboratory, Oxford, Mississippi, United States Department of
 Agriculture.
 PaPer No. 78-2518, Presented at the 1978 Winter Meeting of the American Society
 °f Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 9 p.  7 fig, 4 tab, 13 ref.

 Descriptors;  Sediments, Sediment distribution, Simulated rainfall,  Soil erosion,
 Size, Rainfall intensity, Canopy.

 Row sideslopes of ten soils were studied under simulated rainstorms  to determine
 the size distributions of their eroded (undispersed) sediment.  The  eroded sediment
 sizes for different soils differed considerably.  These distributions were com-
 pared to the size distributions of the dispersed sediment and original surface
 soil.  The undispersed sediment was coarser than the dispersed soil  or sediment,
much coarser for many soils.  For each soil,  the sediment size distribution changed
relatively little with major changes in rain intensity,  continued erosion, and
crop canopy.                           81

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  78:02J-026
  EROSION DEPOSITS IN TILE-DRAINS,
  Paterson,  E.,  and Mitchell,  B.D.
  The Macaulay Institute for Soil Research,  Braigiebuckler,  Aberdeen AB9  2QJ,
  Great Britian.
  Agricultural Water Management,  Vol.  1,  No.  4,  p  311-317, December,  1978.   2  fig,
  1  tab,  6 ref.

  Descriptors:   Tile drains, Tile drainage,  Silting,  Deposition  (sediments). Soil
  erosion, Sedimentation,  Drainage.

  The mechanism  of silting up  of  tile  field  drains  in two heavy  textured  surface
  water gley soils was examined by comparing  the physical and mineralogical
  characteristics  of deposits  in  drains with  those  of the clay soil directly above
  The deposits consisted of  clay, silt and sand  and are distinctly laminated.  They
  appeared to be the result  of internal erosion  of  the soil.  The processes"operative
  Mnnefnfc^  I6 *een! ^"i  i?flow °f  soil throu?h  ^e drain joints;  (b)  sedimenta-
  tion  in the drain;  (c) elution  of very  fine material.  The possibility  that  this
  silting-up  phenomenon  is not uncommon in the tile field drains of surface water
  gley  soils  of Scotland was recognized.


  78:02J-027
 SIZE DISTRIBUTION  OP ERODED MATERIAL FROM SIMULATED  RAINFALL:  EFFECT OVER A RANGE
 OF TEXTURE,
 Gabriels, D., and Moldenhauer, W.C.
 State University, Ghent, Belgium, Department of Agricultural Sciences.
 Soil Science Society of America Journal, Vol.  42, No. 6,  p 954-958, November-
 December, 1978.  1 fig, 4 tab, 16 ref.

 Descriptors;  Soil erosion, Erosion,  Surface sealing, Particle size, Runoff,
 Simulated rainfall, Soil texture,  Soil aggregates, Water  pollution.

 This study  reported size distributions  and  composition of material  detached by  water
 drops and transported in shallow flow.   The size  distributions  of aggregates  and
 primary particles in the splashed,  washed,  and seal material  at different times
 during a laboratory simulated rainfall  were compared for different  textured soils.
 The wash had more finer material than did the  splash.  The  wash and splash  material
 at  equilibrium were not different from  the  original soil, while the seal of all
 soils had a larger silt content  than  the original soils.  The  silt  loam  soil  had
 seals with  about  the same clay content  as the  original  soil, while  silty clay soils
 had seals with  less clay  than the original  soils.   Of significance  from  this  study
 was the low percentage  of dispersed clay being  eroded compared  to the percent of
 Mm» lnT^en,«rigi?aV0il,,?« that  this  Percenta
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                                   SECTION  XI

                                   WATER CYCLE

                         CHEMICAL PROCESSES  (GROUP 02K)


 78:02K-001
 UTILIZATION OF LABELLED UREA AND AMMONIUM SULFATE BY LOWLAND RICE,
 Reddy, K.R., Patrick, W.H., Jr.
 Louisiana State University, Baton Rouge, Department of Agronomy.
 Soil science Society of America Journal, Vol. 42, No. 3, p 465-467, May-June
 1978.  4 tab, 4 ref.

 Descriptors:   Stable isotopes. Ureas, Ammonium compounds, Nitrogen, Fertilizers,
 Fertilization, Rice, Flood irrigation.

 The objective of this investigation was to compare labelled ammonium sulfate and
 urea in their effect on yield and N utilization in field microplots on Crowley
 silt loam (typic albaqualf).   Nitrogen was applied as an early season topdressing
 or as a midseason topdressing and the grain and straw yield and recovery of
 labelled and native N in the grain straw,  and soil were measured.  No significant
 differences in grain and straw yields were observed for the two sources and two
 times of N application.   Ammonium sulfate  and urea did not differ significantly
 in N utilization by the crop.   For both sources the recovery of labelled N in
 the soil-plant system was highest (34 to  55 kg N/ha)  in the plots receiving early
 season topdressing (30 to 38  kg N/ha).   More native soil N was  taken up by the
 plants during 1976 as compared to the 1975  season.


 78:02K-002
 DETERMINATION OF STABILITY CONSTANTS OF METAL-HUMIC ACID COMPLEXES BY POTENTIO-
 METRIC TITRATION AND ION-SELECTIVE ELECTRODES,
 Takamatsu,  T.,  and Yoshida, T.
 National  Institute for Environmental Studies,  Yatabe-cho,  Ibaraki, Japan,  Water
 and Soil  Environment Division.
 Soil Science,  Vol.  125, No. 6,  p  377-386, June,  1978.   8  fig, 4  tab,  19  ref,  14 equ.

 Descriptors:   Heavy metals, Humic  acids, Electrodes, Pollutants,  Copper, Cadmium,
 Lead.

 A  new technique based on the combined use of potentiometric titration  and  ion-
 selective electrodes  was proposed for determining apparent stability constants
 (successive stability constants and  overall stability constants) of divalent metal
 cation  Cu(++), Pb(++), and Cd(++) complexes with humic acids.  Fourteen humic
 acids  from diverse  sources, including humidified rice straw, were  examined.  The
 stability constants  increased with an increase in pH, and the order of values
 obtained was Cu{++)  >  Pb(++) »Cd(++).  The overall logarithmic stability  con-
 stants with the soil  humic acid examined were" 8.65 for Cu(++), 8.35 for Pb(++),
 and  6.25 for Cd(++) at pH 5.0.  The  overall stability constants of Cd(++)  complexes
 ranged from 430,000 to 4.6 times 10  to the 7th power at pH 6.0.  The overall
 stability constants increased with increasing humification in the higher humifi-
 cation range, and the values correspond to the contents of very weakly acidic
 functional groups.  The binding mechanisms of the metal cation complexes with
 humic acids seemed to accompany the  coordinate bonds of undissociated very weakly
 acidic functional groups, in addition to the ionic bonds through COOH and/or OH
 groups.


 78:02K-003
 FACTORS AFFECTING GYPSUM AND CATION EXCHANGE CAPACITY DETERMINATIONS IN GYPSIFEROUS
 SOILS,
 Sayegh, A.H.,  Khan, N.A., Khan,'P., and Ryan, J.
American University of Beirut, Lebanon, Department of Soils and Irrigation.
Soil Science,  Vol. 125, No. 5, p 294-300,  May,  1978.  4 fig,  15 ref.
                                     83

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Descriptors:  Cation exchange, Gypsum, Calcium, Magnesium, Sodium compounds,
Ammonium compounds. Soil profiles, Particle size.

Profiles of gypsiferous soils from the Euphrates basin of Iraq and Syria were
studied.  Increasing fineness of grinding, from 10, 50, 100, and 170 to 270-mesh,
increased the measured amounts of gypsum and soluble Ca + Mg.  These variables
also increased as the soilrwater ratio increased i.e., 1:50, 1:100, and 1:500.
Cation exchange capacity values at 10, 100, and 270-mesh sizes were determined by
various procedures:  IN NaOAC/NH40AC solutions prepared with distilled water and
with 1:1 water-acetone mixture; pretreatments of the soil with 2N BaC12*2H2O,
saturated Na2C2O4, and saturated (COOH)2-2H20 by shaking for variable periods up
to six days.  After each pretreatment, CEC was determined by the conventional
NaOAC/NH4OAC procedure.  Highest values were obtained after pretreatment, the
order being Na2C204, BaC12-2H20, and (COOH)2-2H20.  Values increased with time of
shaking during pretreatment and with increasing fineness of particle size.
Criteria are presented for determining gypsum and CEC in soils containing
significant amounts of gypsum.


78:02K-004
FERTILIZATION DECISION MODEL-A SYNTHESIS OP SOIL AND PLANT PARAMETERS IN A COM-
PUTERIZED PROGRAM,
Kafkafi, U., Bar-Yosef, B., and Hadas, A.
Institute of Soils and Water, Bet Dagan, Israel, ARO-The Volcani Center.
Soil Science, Vol. 125, No. 4, p 261-268, April, 1978.  1 fig, 2 tab, 43 ref,
3 append.

Descriptors:  Fertilization, Computer models, Plant growth, Nitrates, Nitrogen,
Phosphates, Potassium, Ammonium compounds, Nutrient removal, Root development.

A fertilization decision model was suggested, based on soil and plant parameters.
The optimum concentration range of nitrate nitrogen in the soil solution, during
the uptake period of the growing plant, was suggested to be 50 to 250 ppm N-N03
for all soils and plants.  The optimum bicarbonate-soluble P was found to vary
with plant and soil type, and was determined by response experiments.  Percent
recovery of added fertilizer by bicarbonate extraction was used to calculate the
amount of fertilizer needed to raise the extraction'value to the optimum level.
Exchangeable potassium was considered to be the only source important during
the growing season of an annual crop.  The uptake rate of nutrients during the
growing season, depth of root penetration, and sensitivity to ammonium were con-
sidered to be the main plant parameters.  The model calculates, at preset time
intervals, the balance between the quantity of nutrients in the root zone and
uptake by plants.  A decision to add fertilizer is made if a deviation from the
optimum exceeds a predetermined value.


78:02K-005
SIMULATION OF NITROGEN PROCESSES IN SOILS FOR ESTIMATING FERTILIZER REQUIREMENTS,
Kruh, G., Hagin, J., and Sharon, S.
Technion-Israel Institute of Technology, Haifa, Israel, Faculty of Agricultural
Engineering.
Soil Science, Vol. 125, No. 4, p 255-260, April, 1978.  3 fig, 2 tab, 19 ref.

Descriptors:  Fertilization, Computer models, Simulation analysis, Cotton,
Ammonium compounds, Nitrates, Soil moisture, Crop response, Timing.

In a field experiment on cotton, ammonium sulfate was applied to give 60, 120, and
180 kg N/ha, all in winter, early spring, and late spring applications.  A check
treatment was included.  Soil samples to a depth of 120 cm were taken from time
to time, and moisture and nitrate concentrations were measured.  The early spring
fertilization at the two lower levels of application produced higher yields than
the two other application times, with a maximum at the 120-kg N/ha level.  The
highest level of application induced a yield depression.  The early spring appli-
cation produced a nitrate distribution in the soil profile with a peak in the 20-
40 cm depth.  The yield results were partially explained by the nitrate distri-
bution in the soil profile during the early growth period.  A computer program
simulated well, within experimental errors, the nitrate distribution in the soil
profile.  It was concluded that such a program could improve considerably nitrogen
fertilizer requirements and timing predictions.


                                       84

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78:02K-006
HULA VALLEY PEAT:  REVIEW OF CHEMICAL AND GEOCHEMICAL ASPECTS,
Brenner, S., Ikan, R.,  Agron., N.A., and Nissenbaum, A.
Hebrew University of Jerusalem, Israel, Department of Organic Chemistry.
Soil Science, Vol. 125, No. 4, p 226-232, April, 1978.  3 fig, 2 tab, 32 ref.

Descriptors:  Peat, Chemical properties, Pleistocene epoch, Inorganic compounds,
Organic matter, Stable isotopes, Elements (chemical), Geochemistry.

In the Hula Valley, Israel, four layers of peat of Middle Pleistocene to Holocene
age, interbedded with limriic clays and marls, are found above 300-m depth.  The
main detrital minerals are kaolinite, montmorillonite, and illite.  Average ele-
mental values of organic and inorganic matters (on dry basis)  present in each
horizon and average calorific values of each horizon are reported.  Organic con-
stituents of the upper layer have been identified.  A detailed.quantitative in-
vestigation of the distribution with depth in the top peat layer of the humic,
fulvic, and hymatomelanic acids, as well as of the beta-humus and humin, showed
humin to be the dominant fraction of the organic matter.  Analysis of the peat
organic fractions for carbon and hydrogen stable isotopes shows that with depth
the difference in delta C13 between the humic and fulvic acids disappears and the
delta C13 stabilized at around-18 parts per thousand.  The isotope data indicate
the dynamic nature of the fulvic acid in the peat.  The delta D values were around-
60 parts per thousand,  but the data are too meager for any firm conclusion.


78:02K-007
THE NATURE OF BASALT WEATHERING IN ISRAEL,
Singer, A.
The Hebrew University of Jerusalem, Israel, Department of Soil and Water Science.
Soil Science, Vol. 125, No. 4, p 217-225, April, 1978.  5 fig, 17 ref.

Descriptors:  Weathering, Soil formation, Basalts, Aeolian soils, Saprolites,
Clay minerals, Quartz.

Three major weathering forms of upper Cenozoic basalts are recognized:  a weathering
crust, several millimeters thick, at the interface with the massive basalt; a
weathering zone, several centimeters thick, associated with vesicular basalt; and
thoroughly altered basalt saprolite, mostly obtained under prolonged water-saturated
conditions.  The clay fractions in the weathering crust and zone consist of smectite
and kaolinite with halloysite, while, in the saprolite, smectite is the only clay
Mineral formed.  Si02/A1203 ratios change from 6-7 in the rock to 2-3 in the crust
clay, and this decrease represents maximum desilication obtained under eastern
Mediterranean conditions.  With soil development, a resilioation of soil clays
relative to crust clay may take place in the deeper stable profiles.  Soil develop-
ment also involves aeolian accumulation of quartz in the coarser size fractions,
and Fe and K enrichment in the clay fraction.  Grumusols (Vertisols) represent the
mature, stable end products of basalt weathering on uneroded surfaces in the semi-
arid and subhumid parts of the eastern Mediterranean.  In the more humid parts,
Red and Brown Mediterranean soils  (Xeralfs) become dominant.


78:Q2K-008
APPLICATION OF THE ELECTRICAL DOUBLE LAYER THEORY TO PREDICT ION ADSORPTION IN
MIXED IONIC SYSTEMS,
Ravina, I., and Gur, Y.                                          . ,  ,  ..   .
Technion-lsrael Institute of Technology, Haifa, Israel, Faculty of Agricultural

sSiinIcience, Vol. 125, No. 4, p 204-209, April, 1978.  3 fig, 3 tab, 16 ref, 16 equ.

Descriptors:  Cation adsorption, Alkali metals, Ions, Hydration, Soil chemistry.

A Poisson-Boltzmann equation including hydration forces and the dielectric saturation
effects for describing the electric double layer was presented and compared with
the Gouy-Chapman theory.  Ionic concentrations in the double layer were calculated
by the revised equation showing the specific adsorption of the various alkali metal
cations.
                                       85

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 78:02K-009
 RESIDUAL FORMS OF FERTILIZER NITROGEN IN FIELD SOILS,
 Smith, S.J., Chichester, F.W., and Kissel, D.E.
 U.S. Agricultural Water Quality Management Laboratory, Durant, Oklahoma.
 Soil Science, Vol. 125, No. 3, p 165-169, March, 1978.  1 fig, 2 tab,  17 ref.

 Descriptors:  Fertilizers,  Nitrogen, Chemical analysis, Nitrates, Chemical reactions,
 Aerobic conditions, Soil chemistry.

 Residual fertilizer N was characterized in Houston Black clay and Keene silt loam
 surface soils from recent field microplot-N balance studies involving liberal (328-
 560 kg N/ha) 15N-labeled rates.  Results indicate residual N is readily distributed
 in all_the organic and inorganic soil N forms, even after the first cropping season.
 An equivalent distribution of the residual N with the indigenous soil N, however,  had
 not occurred after three years.  During this period the residual N was more than
 twice as susceptible to mineralization as the soil  N.  Most of the residual N was
 incorporated in amino acid N-forms.


 78:02K-010
 MECHANISM OF ZINC ADSORPTION BY IRON AND ALUMINUM OXIDES,
 Kalbasi,  M., Racz, G.J.,  and Loewen-Rudgers,  L.A.
 University of Manitoba, Winnipeg, Manitoba, Canada,  Department of Soil Science.
 Soil Science, Vol. 125, No.  3, p 146-150,  March,  1978.  1  fig,  1 tab,  13 ref.

 Descriptors:  Adsorption,  Zinc, Iron oxides,  Aluminum, Ion exchange, Aqueous solu-
 tions,  Soil  chemistry,  Hydrogen ion concentration.  Chlorides.

 Adsorption of Zn  from aqueous  solutions  of ZnC12  by  hydrated A1203  and Fe203 was
 highly  pH-dependent and increased markedly with increasing pH.   Fe203  had a higher
 Zn adsorption capacity, at  equivalent pH values,  than A1203.   Experimental observations
 suggested  that  surface  aqus  (-OH2)  and hydrono (-OH)  groups  were  involved in Zn ad-
 sorption.   In addition, experimental observations lead to  the  postulation that two
 types of adsorption,  specific  and nonspecific,  depending upon  reversibility (exchange-
 ability with Ba(2+)), occurred.   Specific  and  nonspecific  adsorptions  of Zn(2+) were
 accounted  for 60  to  90% and  40 to 10%  of the  total Zn adsorption  respectively.  For
 specific adsorption,  an olation bridge structure between Zn(2+)  and two  surface -OH2
 groups was postulated;  and  for nonspecific adsorption,  a single-bond structure in
 which ZnCl(+) replaced  one H(+)from surface -OH2 groups was  postulated.   The ratio
 of specific  to  nonspecific adsorption  increased with  increasing pH.  It  was  concluded
 that specific adsorption of  Zn by A1203  and Fe203 may be at  least partially  responsi-
 ble for the  frequency reported fixation  and unavailability of added Zn  to  soils.


 78:02K-011
 CHEMICAL CHARACTERIZATION OF LOCAL AND STRATOSPHERIC  PLUTONIUM IN OHIO SOILS
 Muller, R.N.
 Argonne National  Laboratory, Argonne,  Illinois, Radiological and  Environmental Re-
 search Division.
 Soil Science, Vol. 125, No.  3,  p  131-136, March, 1978.  1  fig, b  tab, 21 ref, 1 append.

 Descriptors:  Isotope studies,  Chemical  analysis, Ecosystems, Industrial wastes, Soil
 contamination, Ohio.

 The  chemical  nature of  plutonium derived from stratospheric fallout and  industrial
 sources was  studied in  three agricultural soils.  The majority of the soil plutonium
was  associated with a reductant-soluble, hydrous oxide phase that, under most condi-
 tions of terrestrial ecosystems, remains essentially  immobile.  The proportion of
plutonium associated with organic matter  (0.1N NaOH-extractable) varied among soils,
and  increased with decreasing particle size in the same soil.  In a soil containing
 238Pu from a  local fabrication facility and 239,240Pu from stratospheric fallout,
isotopic ratios between the NaOH-extractable and residual phases were essentially  con-
stant, indicating that,  in these soils, plutonium from both sources behaves similarly.
The distribution of soil plutonium with particle size appears to be most directly
related to the mass of the soil particle.
                                       86

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 78-.02K-012
 EFFECTS  OF TEMPERATURE AND TIME ON HYDROXY ALUMINUM PHOSPHATE-MONTMORILLONITE
 COMPLEX,
 Webber,  M.D.
 Soil Research Institute,  Agriculture  Canada,  Ottawa,  Ontario  KlA OC6.
 Soil Science,  Vol.  125, No.  2,  p 107-114,  February,  1978.   3  fig,  3  tab,  16  ref.

 Descriptors:   Montmorillonite,  Aluminum,  Phosphates,  Clay  minerals,  Temperature,  Time,
 Solubility, Suspension, Aerobic conditions, Acidic  soils.

 Hydroxy  aluminum phosphate-montmorillonite complex  persisted  for 320 days  in aqueous
 aerobic  suspensions that  exhibited a  pH range of  2.5  to  3  and were maintained at  10,
 25,  and  35C.   There were  small  changes in  its chemical and x-ray diffraction properties
 with time,  and these occurred more quickly as the temperature was  raised.  It persisted
 for  100  to 200 days at 50C,  but then  variscite  formed and  interlayer material dis-
 appeared  from the clay.   Solubility calculations  indicated that  preparations con-
 taining  the complex were  undersaturated with  respect  to  gibbsite and supersaturated
 with gibbsite,  but  saturated with  variscite.  Seeding the  preparations with  variscite
 and  aging at  25C did not  cause  variscite  to form.   It is postulated  that amorphous
 hydroxy  aluminum phosphate,  which  is  an important soil-fertilizer  reaction product
 and  a good source of phosphorus for plants on neutral soil, is likely to persist
 indefinitely  in temperate acid  soils.


 78:02K-013
 REACTION  PRODUCTS AND SOLUBILITY OF APPLIED ZINC  COMPOUNDS IN SOME MANITOBA  SOILS,
 Kalbasi,  M.,  Racz,  G.J.,  and Lewen-Rudgers, L.A.
 University of  Manitoba, Winnipeg,  Manitoba, Canada, Department of  Soil Science.
 Soil Science,  Vol.  125, No.  1,  p 55-64, January,  1978.   4  fig, 6  tab, 26 ref.

 Descriptors:   Zinc,  Solubility,  Sulfates,  Sulfides, Ammonium  compounds, Fertilizers,
 X-ray diffraction,  Calcareous soils,  Soil  chemistry.

 2nS04, ZnEDTA,  ZnS,  and ZnSO4 plus  NH4H2P04 were  banded  in soils,  and the solid-
 Phase zinc compounds  were identified  using x-ray  diffraction  analysis.  Solubility
 of zinc in soil  adjacent  to  the fertilizer band was determined by  measuring  the zinc
 concentration  in soil-water  extracts.  The reaction product in a noncalcareous soil
 
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 this  time  and  unrecoverable  in  the NaHCO3 solution upon  immediate extraction.  Thus,
 the labile compounds,  like RNA,  its  four 3' nucleotides, and glycerophosphates were
 recoverable in the  0-5M NaHCO3-extracting solution (pH 8.5) of Olsen et al., while
 the Na-phytate,  a relatively resistant compound, was not.  Native Po was only slightly
 affected.  However,   a  relatively constant amount of native Po was extracted, irre-
 spective of extraction periods  lasting 0.5 to 6 h.


 78:02K-015
 THE BEHAVIOR OF  SULPATE ON SALT  INPUT IN PODZOLIC BROWN EARTH,
 Khanna, P.K.,  and Beese, F.
 Georg-August University, Buesgenweg  2, Goettingen, West Germany, Institute of Soil
 Science and Forest  Nutrition.
 Soil  Science,  Vol.  125, No.  1, p 16-22, January, 1978.  4 fig, 3 tab, 17 ref.

 Descriptors:   Sulfates, Salts, Adsorption, Chemical precipitation, Podzols, Effluents*
 Leachate,  Sorption,  Inorganic compounds.

 The behavior of  sulfate concentration in the leachate of an acid podzolic brown earth
 was studied, when a  slug of  neutral  salt (KCl + KN03) passed through the upper
 sulfate-enriched layers of the soil.  The effluent of five undisturbed soil columns
 was collected  daily, and H(+), Cl(-), and SO4(—) concentrations were measured.  A
 constant flux  of water, either 1.0 cm/day or 0.3 cm/day, was maintained.  Sulfate
 concentration  in the leachate showed a decrease when the salt passed the columns.
 The decrease corresponded with an increase of H(+) and Cl(-) concentrations.  The
 behavior of sulfate was almost the same irrespective of the flow rates.  At the lower
 rate, sulfate  retention was  about twice that at the higher rate.  Though precipi-
 tation of  basic  aluminum sulfates cannot be excluded, the behavior of sulfate must
 be interpreted in terms of specific  adsorption.


 78:02K-016
 FIELD PERSISTENCE AND MOVEMENT OF TRIFLURALIN IN TWO SOIL TYPES,
 Duseja, D.R.,  and Holmes, E.E.
 Tennessee  State University, Nashville.
 Soil Science,  Vol. 125, No.  1, p 41-48, January, 1978.  1 fig, 8 tab, 27 ref.

 Descriptors:   Herbicides, Weed control, Weeds,  Johnson grass, Oats,  Movement,
 Persistence.

 Trifluralin (alpha,  alpha, alpha-trifluoro-2,  4, dinitro-N, N-dipropyl-p-toluidine)
was applied in 1973 to Egam  load and Season clay field plots.  Trifluralin
persistence  and movement in both soils was essentially the same, even though higher
herbicide  rates were applied to Beason clay,  according to manufacturer's recommenda-
 tions.  There was an increasing  trend of herbicide residues with excessive rates of
 trifluralin application.   The herbicide essentially dissipated from soils in five
months, with only 2.1 percent and 0.4 percent of the initially applied amounts re-
maining in  the soil profile,  in  the Egam and Beason soils,  respectively, at the
 highest (two times)  rate of herbicide application.  No herbicide was detected in the
 soil the following spring (eleven months after application).  Herbicide persistence
 could be described by a first-order kinetics.   Downward movement of trifluralin
 under the  conditions of this experiment did occur to the eight in depth; further
 penetration of herbicide was essentially nil.   Apparently,  upward movement of
 trifluralin also occurred under  these conditions.  The control of Johnson grass and
 two broadleaf weed species present in the soil lasted from four to five weeks only.


 78:02K-017
NITRAPYRIN  DEGRADATION AND MOVEMENT IN SOIL,
Touchton,  J.T., Hoeft, R.G.,  and Welch, L.F.
Georgia University,  Georgia Station, Experiment, Department of Agronomy.
Agronomy Journal, Vol. 70, No. 5, p 811-816,  September-October, 1978.  5 fig, 5 tab,
 13 ref.

Descriptors:  Nitrification,  Inhibitors,  Degradation (decomposition), Movement,
Ammonium compounds,  Ammonia,  Fertilizers, Soil chemical properties,  Soil physical
properties.
                                       88

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 Nitrapyrin [2-chloro-6-(trichloromethyl)pyridine]  is  applied with ammonium-N
 fertilizers to control nitrification in soil.   However,  little information is avail-
 able on the persistence or loss of field-applied nitrapyrin.   The objective of this
 study was to monitor movement and degradation  of nitrapyrin in soil.   Nitrapyrin
 was applied with anhydrous ammonia in the fall of 1975  and spring of  1975  and 1976.
 Measurable quantities of nitrapyrin were not found beyond  7.5 cm from the  point of.
 release in the soil.  The distance that nitrapyrin moved from the point of release
 in the soil was not affected by nitrapyrin rates.   Greater nitrapyrin movement was
 not detected in one direction from the point of release  in the soil than in another
 direction.  Increasing rates of anhydrous ammonia had no effect on nitrapyrin movement
 of degradation.  The most rapid rate of degradation occurred soon after application
 and decreased with time.   The data suggest that nitrapyrin degradation and movement
 will depend on the physical and chemical characteristics of the soil.   Even though
 degradation rates decreased with time,  no indication  was found to prove that soil
 accumulations of nitrapyrin will result from once-a-year applications.


 78:02K-018
 EFFECT OF NITRAPYRIN ON NITRIFICATION OF FALL  AND SPRING-APPLIED ANHYDROUS AMMONIA,
 Touchton..  .T.T., Hoeft,  R.G.,  and Welch,  L.F.
 Illinois  University, Urbana,  Department of Agronomy.
 Agronomy  Journal,  Vol.  70,  No.  5,  p 805-810, September-October,  1978.   5 fig,  5
 tab,  15 ref.

 Descriptors:   Nitrification,  Inhibitors,  Denitrification,  Nitrates, Fertilizers,
 Ammonia,  Leaching,  Timing,  Rates of application, Soil types.

 Nitrification of ammonium fertilizers  in  late  fall  and early  spring and subsequent
 nitrate losses through  leaching and denitrification are  a  continuing economical
 and environmental  concern.   To  evaluate  the effects of nitrapyrin  on nitrifica-
 tion,  anhydrous ammonia with  and without  nitrapyrin was  applied  in the  fall  and
 spring to  poorly drained  soils.   Nitrogen and  nitrapyrin rates ranged  from  0  to
 268 and 0  to  1.12  kg/ha,  respectively.   Detailed sampling  from ammonia  retention
 zones  was  conducted throughout  the fall,  spring, and  summer.  Effects of nitra-
 pyrin  on  nitrification  varied with time of application,  nitrapyrin rate, and
 soil type.


 78f02K-019
 NITROGEN  RELEASE CHARACTERISTICS OF ISOBUTYLIDENE DIUREA AND  ITS EFFECTIVENESS
 AS  A SOURCE OF N FOR FLUE-CURED TOBACCO,
 Miner,  G.S.,  Lilly,  J.P., and Terry, D.L.
 North  Carolina State University,  Raleigh,  Department of  Soil  Science.
 Agronomy Journal, Vol.  70,  No.  3,  p 434-438, May-June, 1978.  3  fig,  3  tab,  12
 ref.

 Descriptors:   Nitrogen, Leaching,  Tobacco,  Nutrient removal. Fertilizers, Parti-
 cle size.

 The objectives  of this  study were  to investigate the release characteristics of
 isobutylidene  diurea (IBDU), with N-release characteristics dependent primarily
 upon the effects of  particle  size on chemical dissolution rather than the effects
 of  environmental variation on biological activity, in laboratory and  greenhouse
 studies and to  evaluate it as a  source of N for flue-cured tobacco in the field.
 Urea, NaN03, and four particle  sizes of IBDU (1.05, 0.75, 0.55, and 0.40 mm) were
 applied at rates of  200 and 400 mg N per kg of soil to a Norfolk sandy loam
 (Typic paleudult) in lysimeters  and subjected to leaching at ten intervals  over
 a 109-day period.  Percentage removal of N  from these sources were observed at a
 different leaching time.  The effects of particle size of IBDU on dry matter and
 N uptake were studied to determine  their N release characteristics.  IBDU parti-
 cle sizes of 1.05 and 0.40 mm were compared with NaN03 and Urea as N  sources for
 flue-cured tobacco.


 78:02K-020
FATE OF FERTILIZER NITRATE APPLIED TO COASTAL BERMUDAGRASS  ON A SWELLING CLAY SOIL,
Kissel, D.E., and Smith, S.J.
Texas Agricultural Experiment Station, Temple,  Blackland Research Center.
Soil Science Society of America Journal, Vol. 42, No.  1,  p 77-80, January-
February,  1978.  3 tab, 16 ref.

                                       89

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 Descriptors:   Nitrates,  Denitrification, Fertilizers, Bermudagrass, Soil physical
 properties.

 The  disposition  of  N  fertilizer applied  to  Coastal bermudagrass  in the  field over
 two  growing  seasons was  determined by  applying  560 kg N/ha  as  Ca(N03)2  tagged with
 7.599  atom %  15N to a field microplot  during  1974 and measuring  various components
 of the N balance.   Plant uptake of residual N was measured  during  1975.  Forty-nine
 percent of the applied N was recovered in harvested forage in 1974.  About 40% of the
 applied N remained  in the soil as residual  N  at the end of  1974.  About 10% of
 N was  unaccounted for, indicating that denitrification losses  were no more than
 10%  of the applied  N.  Most of the residual N at the end of the  first growing
 season was immobilized N or was present  in  the  root system  of  the grass.  Immobili-
 zation is, therefore,  a major factor causing low recovery of applied N by Coastal
 bermudagrass  on  swelling clay soils.   Moreover,-since only  17% of the residual
 N was  recovered  in  forage during 1975  (7% of  the N applied  in  1974) , most of
 the  immobilized  N was  not available the  following year.


 78:02K-021
 IMPORTANCE OF THE ORGANIC PHOSPHORUS FRACTION IN EXTRACTS OF CALCAREOUS SOIL,
 Abbott,  J.L.
 Cotton Research  Center,  4201 E. Broadway, Phoenix, Arizona   85040.
 Soil Science  Society  of  America Journal, Vol. 42, No. 1, p  81-85, January-February,
 1978.   2  fig,  8  tab,  10  ref.

 Descriptors:   Soil  analysis, Calcareous  soils,  Phosphorus,  Forage sorghum, Ferti-
 lizers,  Organic  compounds, Soil chemistry.

 Laveen clay loam soil  samples were collected  immediately following the  harvest
 of forage  sorghum (Sorghum bicolor (L.) Moench).  Two sets  were prepared before
 growing turnips  (Brassico rapa L.) as  the test  crop in the  greenhouse.  One set
 was without treatment  and the other, to  simulate winter and spring conditions,
 was  incubated for twenty  days after addition  of  N and dextrose.  Phosphorus uptake
 by turnips and changes in soil P forms were positively correlated with  correspond-
 ing measurements  taken during the growth of the  sorghum crop.  Correlations
 among  P  uptake by forage  sorghum, turnips,  and  soil P measurements indicated
 their  value in predicting available P.  Prediction values for  two of the procedures
 were improved by including the extractable  organic P with the  inorganic P for the
 incubated  soil.  Results  showed that (1)  time of sampling,  (2) the crop to be
 grown,  (3) the method of  extraction, and (4)  the means of converting organic P
 to a measurable  inorganic form in the extract are of prime  concern in deciding
 when to  include  extractable organic P in the P evaluation of a given soil.


 78:02K-022
 MINERALIZATION,  IMMOBILIZATION AND NITRIFICATION,
 Broadbent, F.E.
 California University, Davis, Department of Land, Air and Water Resources.
 Proceedings of National Conference on Management of Nitrogen in Irrigated Agri-
 culture, California University, Sacramento, California, p 109-134, May  15-18,
 1978.   5 fig,  3 equ, 33 ref.

 Descriptors:    Nitrogen, Nitrification, Ammonia, Decomposing organic matter,  Soil
microorganism, Inorganic  compounds,  Pollutants,  Inhibitors.

 The decomposition of organic substances containing nitrogen through the acti-
 vities of soil microorganisms and resulting in the release of some of the nitro-
 gen as ammonia is called  nitrogen mineralization.  Net mineralization occurs when
 the quantity of nitrogen  in the material undergoing decomposition exceeds the
 needs of the microbial population for nitrogen to produce new cells.   If the
 decomposing substances do not contain enough nitrogen to meet the needs of the
microbial population,  any inorganic nitrogen present in the  soil  will  be utilized
by the microbes and converted to cell protein and other nitrogenous compounds.
 This process is called immobilization.   In a sense the assimilation of inorganic
 nitrogen by growing plants is also immobilization,  but this  discussion considers
only the microbiological process.   The nitrogen supplying capacity of soils
depends to a  large extent on rates of mineralization and immobilization.  Various
procedures have been utilized to obtain estimates of nitrogen mineralization
over a growing season, the most successful of which have been based on incubation


                                       90                                    "

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 of soil samples under controlled conditions for a few weeks.   Desirable management
 practices should favor not only efficient utilization of fertilizer nitrogen,
 but also maximum crop uptake of mineralized, nitrogen.  Experiments with isotopi-
 cally labeled fertilizers indicate that  these two objectives are compatible
 with each other and also with the need to minimize leachable nitrate.


 78:02K-023
 SIMULATION OF NUTRIENT LOSS FROM SOILS DUE TO RAINFALL ACIDITY,
 Reuss,  J.O.
 Environmental Research Laboratory-Corvallis,  Corvallis, Oregon,  Office of Research
 and Development,  United States Environmental  Protection Agency.
 Publication No.  EPA-600/3-78-053, May, 1978.   45 p,  12 fig,  4 tab, 18 ref.

 Descriptors:   Rainfall,  Water analysis,  Water chemistry,  Soil science,  Soil
 chemistry, Plant nutrition, Ecology.

 This paper describes a simulation model  that  provides a quantitative system uti-
 lizing  established relationships from soil chemistry to predict  the most likely
 effect  of rainfall acidity on the leaching of cations from noncalcareous soils.
 The model utilizes the relationships  between  lime potential  (pH  -  l/2pCa) and
 base saturation  described by Clark and Hill (Soil Sci.  Soc. Amer.  Proc.  28:490-
 492,  1962)  and Turner and Clark (Soil Sci.  99:194-199,  1964),  the  equilibrium
 between CO2  partial pressure and H+ and  HCO3- in solution, the apparent solubi-
 lity product of  AL(OH)3,  the equilibrium of cations  and anions in  solution,  the
 Freundlich isotherm description of ions  between the  solution  and sorbed or  ex-
 changeable phases.   Ionic composition of leachates in response to  rainfall
 composition  can  thus be  computed.  Ions  considered in the present  version are
 H+,  Ca2+,  A13+,  S042-, CL-,  and HC03-.   The model predicts almost  exact chemical
 equivalence  between basic cation removed in the leachate  and  strong acid anions
 entering  the system in  the rainfall  of  pH -  l/2pCa  is  above  3.0,  at which  point
 the base saturation will  generally not exceed 20%.   At  lower  pH  -  l/2pCa values
 leaching of  anions  in association with H+ and A13+ becomes significant  and  these
 cations  predominate when  pH -  l/2pCa  falls below 2.0.


 78:02K-024
 MULTICOMPONENT CATION ADSORPTION DURING  CONVECTIVE-DISPERSIVE  FLOW THROUGH SOILS:
 EXPERIMENTAL  STUDY,
 Lai,  s-H., Jurinak,  J.J.,  and Wagenet, R.J.
 Utah  State University, Logan, Department of Soils  and Biometeorology.
 Soil  Science  Society of America Journal,  Vol.  42,  No. 2, p  240-243,  March-April,
 1978.  5  fig,  14 ref,  2 equ.

 Descriptors:   Cation adsorption-,  Cation  exchange,  Soil water movement, Solutes,
 Sodium, Magnesium,  Calcium,  isotherms.

 The adsorption of H(+), Mg(2+),  and Ca(2+)  from aqueous solutions  flowing through
 soil was  examined under different total  cation  concentrations  and  input pulse
 volumes.  The  pulses  of H(+) and Mg(2+),  which  were  introduced into  a Ca(2+)-
 saturated Yolo loam soil  column,  appeared separately in the effluent.  The degree
 of separation  decreased with total concentration, but was not  affected signifi-
 cantly by the  pulse  volume.  At  constant  total  concentration,  the  initial
 appearance of  the Mg(2+)  pulse was delayed with  increasing pulse volume.  The
 experimental results were  compared to theoretical calculations based on a single
 component linear equilibrium model.  At a low loading (a small amount of adsorb-
 ate with respect to  a large amount of adsorbent), the agreement of the theoreti-
 cal model and  the experimental results was satisfactory.  However, when the
 loading was increased, the discrepancy between  the calculated values and the
 experimental results  increased.


 78:02K-025
ADSORPTION OF ALDICARB BY CLAYS AND SOIL ORGANO-CLAY COMPLEXES,
Supak, J.R., Swoboda, A.R., and Dixon, J.B.
Texas A&M University, College Station,  Department of Soil and Crop Science.
Soil Science Society of America Journal,  Vol.  42, No. 2, p 244-248, March-April,
1978.  3 fig,  3 tab, 22 ref.
                                       91

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 Descriptors:   Carbamate pesticides, Systemics,  Insecticides, Adsorption, Illite,
 Montmorillonite,  Kaolinite,  Clay minerals.

 Adsorption  experiments conducted with S-methyl-14C-aldicarb resulted  in what
 appeared  to be negative adsorption  (exclusion)  of the toxicant on Ca- and Al-
 saturated montmorillonite clays.  Calculated exclusion volumes indicated that
 aldicarb  did not  penetrate  the  interlamellar region.  Aldicarb was excluded from
 at  least  the first  16 layers of water on external surfaces of montmorillonite.
 Positive  adsorption occurred with Ca- and Al- saturated illite and kaolinite
 clays.  Equilibration of aldicarb solutions with one acid and two calcareous
 Vertisols,  and with the organo-clay complexes isolated from these Vertisols,
 produced  negative adsorption isotherms for the  acid and positive adsorption iso-
 therm for calcareous adsorbents.


 78:02K-026
 POTASSIUM AND  RUBIDIUM ADSORPTION AND DIFFUSION IN SOIL,
 Baligar,  V.C.,  and  Barber,  S.A.
 Guelph University,  Ontario, Canada, Department  of Land Resource Science.
 Soil Science Society of America Journal, Vol. 42, No. 2, p 251-254, March-
 April, 1978.   2 fig, 4 tab, 10  ref, 6 egu.

 Descriptors:   Cation adsorption, Cation exchange, Potassium, Cations, Diffusion,
 Correlation analysis, Organic matter.

 The adsorption of K and Rb  by four soils was investigated to determine the
 differences in adsorption of K  and Rb which may occur and how they are affected
 by soil properties  with the view of using this  information to evaluate the in-
 take mechanisms for K and Rb by plant roots" growing in soil.  Rubidium was
 adsorbed  preferentially to  K by all four soils.  Selectivity coefficient k sub
 Rb/K, indicating  the size of the effect ranged  from 1.9 to 4.4.  Adding K
 decreased k sub Rb/K, increased the amount of nonexchangeable Rb and  decreased
 exchangeable Rb.  There was a negative correlation (coefficient of determination
 = 0.78) between exchangeable K  in the soil and  k sub Rb/K.  The level of K in
 the soil  had a greater effect on k sub Rb/K than varying types of exchange sites
 present due to differences  in clay and amounts  of organic matter in the four
 soils investigated.  The size of the selectivity coefficient'indicated that the
 difference  between  K/Rb ratios  in the solution  and exchange phases of these soils
 used and  differences between soils made them suitable for use in plant uptake
 studies of  the mechanisms of K  and Rb uptake.


 78:02K-027
 THE DISTRIBUTION  OF MICRONUTRIENT CATIONS IN SOIL UNDER CONDITIONS OF VARYING
 REDOX POTENTIAL AND pH",
 Sims, J.L., and Patrick, W.H.,  Jr.
 Kentucky  University, Lexington, Department of Agronomy.
 Soil Science Society of America Journal, Vol. 42, No. 2, p 258-262, March-April,
 1978.  5  tab,  19  ref.

 Descriptors:   Iron, Manganese,  Zinc, Copper, Organic matter, Nutrient removal,
 Flooding, Toxicity.

 A laboratory study was conducted to determine the influence of redox potential
 and soil  pH on the distribution of Fe, Mn, Zn,  and Cu in Mhoon silty clay loam
 soil (Typic Fluvaguents)  and to provide insight into factors affecting micro-
 nutrient  dissolution and mobility in soil.  Generally, greater amounts of Fe, Mn,
 Zn, and Cu  were found in  the Na acetate  (exchangeable)  and pyrophosphate  (organic)
 extractions at  low pH and Eh than at high pH or Eh.  In contrast, the amounts
 (except Mn) in  the water-soluble, NH2OH-HC1, and oxalate fractions were greater
 at high pH  or  Eh.  Although the micronutrients were brought into solution at
 low pH and  Eh,   much of the  soluble cations soon associated with the exchange-
 able and organic  fractions.  After reduction, mobilized Fe associated about
 equally with the  exchangeable,  organic,  and NH20H-HC1 fractions; immobilized Mn
with the exchangeable and water-soluble fractions; mobilized Zn with the organic
 fraction; and  the mobilized Cu with the organic and water-soluble fractions.
 Separation  of  the water-soluble fraction into free ions and those complexed by
 soluble organic matter indicated that micronutrient cations were complexed by
organic matter  to a greater extent in reduced soil.


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78:02K-028
DETERMINING SOIL GYPSUM CONTENT AND EXPRESSING PROPERTIES OF GYPSIFEROUS SOILS,
Nelson, R.E., Klameth, L.C., and Nettleton, W.D.
National Soil Survey Laboratory, Lincoln, Nebraska, Soil Conservation Service.
Soil Science Society of America Journal, Vol. 42, No. 4, p 659-661, July-August,
1978.  1 fig, 2 ref, 18 egu.

Descriptors:  Gypsum, Sulfates, Soil water, Soil chemical properties, Soil tests,
Soil chemistry.

The standard method for measuring the gypsum content of soils is a lengthy one,
partly because of the presence of Na and Mg sulfates in most gypsic horizons,
and partly because of the difficulty in dissolving all the gypsum in the sample.
A more rapid method, sufficiently accurate for taxonomic uses, has been developed
and is based on loss of crystal water of gypsum upon heating to 105 C.  Percent
gypsum, calculated on an oven-dry weight basis from loss of crystal water,
equals 1.038 x percent gypsum by the standard chemical method + 0.17.  The
standard error of estimate for the new methods is + 1.8% gypsum.  Equations are
given for expressing properties of gypsiferous soils on an oven-dry + crystal
water of gypsum weight basis.


78:02K-029
THE ACETYLENE INHIBITION METHOD FOR SHORT-TERM MEASUREMENT OF SOIL DENITRIFICATION
AND ITS EVALUATION USING NITROGEN-13,
Smith, M.S., Firestone, M.K., and Tiedje, J.M.
Michigan State University, East Lansing, Department of Crop and Soil Sciences.
Soil Science Society of America Journal, Vol. 42, No. 4, p 611-615, July-August,
1978.  1 fig, 6 tab, 11 ref.

Descriptors:  Denitrification, Inhibitors, Nitrogen, Reduction  (chemical),
Anaerobic conditions, Aerobic treatment.

Acetylene was found to effectively inhibit the reduction of N20 by anaerobic
soils.  With concentrations of C2H2 above 0.1 atm, added N03(-) was quantita-
tively converted to N2O and added N2O was reduced at an insignificant rate.
Experiments with 13N demonstrated that at low soil nitrate concentrations at
least 0.1 atm C2H2 was required for effective inhibition.  Denitrification rates
determined by 13N and by C2H2 inhibition methods correlated well, as did deter-
mination of N2O/(N2 + N2O).  The methods also revealed that an acceleration in
denitrification rate occurred within a few hours after soil was exposed to
anaerobic conditions.  The acetylene method was generally used to measure deni-
trification rates in soils incubated as anaerobic slurries, but was also used
to determine rates for field moist aggregrates incubated anaerobically and
aerobically.  When assayed as anaerobic slurries, initial denitrification rates
ranged from 0.1 to 0.7 mmoles N gas/soil/min for the mineral soils examined.
The denitrification rate in aerobic aggregrates was approximately 1,000 times
less, showing the strong inhibitory effect of 02 on the indigenous denitrifying
enzymes.


78j02K-030
THE MECHANISM OF SULFATE ADSORPTION ON IRON (OXIDES,
Parfitt, R.L., and Smart, R. St. C.
Griffith University, Nathan. 4111, Queensland, Australia, School of Science.
Soil Science Society of America Journal, Vol. 42, No. 1, p 48-50, January-
February, 1978.  5 fig, 2 tab, 17 ref.

Descriptors:  Sulfates, Adsorption, Iron oxides, Isotherms, Spectroscopy,
Structural models, Soil chemistry.

Adsorption isotherms were determined for sulfate adsorption on iron oxides under
acid conditions.  The product of the surface reaction between the iron oxides
and sulfate ions was examined by infrared spectroscopy which showed four bands
in the upsilon S-O stretching region.  Thus a structural model could be obtained
for the reaction.  Two surface hydroxyl groups (or OH2(+) ions) are replaced by
one sulfate ion, and two oxygen atoms of the sulfate ion are coordinated each
to a different Fe(3+) ion, resulting in the binuclear bridging surface complex
Pe-o-S(O2)-0-Fe.  The complex is formed on the surfaces of goethite  (alpha-FeOOH) ,


                                       93

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  akaganeite (beta-FeOOH),  lepidocrocite (gamma-FeOOH),  hematite (alpha-Fe2O3)  and
  amorphous ferric hydroxide.


  78:02K-031
  POTENTIAL USE OF FINELY DISINTEGRATED IRON PYRITE IN SODIC AND IRON-DEFICIENT
  SOILS r
  Vlek, P.L.G.,  and Lindsay, W.L.
  Colorado  State University, Fort  Collins,  Department of Agronomy.
  Journal of Environmental  Quality,  Vol.  7,  No.  1,  p 111-114,  January-March,  1978.
  3  fig, 3  tab,  15 ref.

  Descriptors:   Pyrite, Oxidation, Sulfur,  Fertilizers,  Mine wastes,  Soil  amendments,
  Colorado.

  The rate  of chemical oxidation of  iron  pyrite  in  water was measured as a function
  of particle size.  Reducing the particle  size  greatly  increased the rate of oxi-
  dation.   For pyrite > 250 microns, the  PH  of the  solution  leveled off at 5
  after six hours  while the clay size pyrite  dropped to  pH4  within twenty-four
  hours.  in these studies, pyrite was applied at 1%  initially with an additional
  1% after  one month to a slightly sodic, iron-deficient, loamy sand  soil  from
  Colorado.  The soil/water ratio was 1:2.  When clay size pyrite was used, the
  pH of the soil decreased from 8.3  to 7.8 after 1 mo and to 5.7 after 2 mo   The
  coarser pyrite decreased the PH only slightly.  No significant change in  the
  composition of exchangeable ions occurred during the first month, but the composi-
  tion had  changed sufficiently after 2 mo to flocculate the clay   The DTPA-
 extractable iron increased from 1.5 to  64 PPm for the  finest pyrite treatment
 during 1 mo, copper double,  and manganese quadrupled during this period.   Finely
 disintegrated pyrite may be useful for reclaiming slightly sodium-affected soils
 or for providing slow release available iron.


 78:O2K-032
 PHOSPHATE ADSORPTION-DESORPTION CHARACTERISTICS OF SOILS AND BOTTOM SEDIMENT IN
 THE MAUMEE RIVER BASIN OF  OHIO,
 McCallister,  D.L., and Logan,  T.J.
 Texas  A  &  M University,  College Station, Department of  Agronomy
 Journal of Environmental Quality,  Vol.  7,  No.  1,  p 87-92,  January-March,  1978.
 z rig, 6  tab,  27 ref.

 Descriptors:   Adsorption,  Eutrophication,  Pollutants, Phosphates,  Runoff, Isotherms.

 Langmuir adsorption isotherms  showed  that  Maumee  River  Basin sediments had
 adsorption capacities  10 to 20  times  greater than  Basin soils.   Although  the
 soil clay  fractions had adsorption  capacities  higher than  the whole  soil, they
 were considerably less  than those of  the sediments and  the  difference is  attri-
 buted  to the higher content of amorphous or low-range order iron and aluminum
 components in  the bottom sediments.   Equilibrium phosphorus concentration (EPC)
 and phosphorus  desorbed was similar for  soil and sediments  as well as total  P
 indicating that although the bottom sediments have a high capacity to adsorb P,
 this capacity has not been realized.  Correlations  between adsorption-desorption
 parameters and  soil/sediment properties  are presented.   Bray  PI  "available" P
 was highly correlated with EPC and  P  desorbed in the soils  but  to a  lesser
 extent in  the bottom sediments.  CDB  and oxalate extractable-P was highly cor-
 related with P  adsorption capacity  in the bottom sediments  but  not in the soils.


 78:02K-033
 MICROBIAL  ASPECTS OF THE VOLATILE LOSS OF APPLIED MERCURY (II) FROM  SOILS
 Landa,  E.R.                                                               '
 Oregon State University, Corvallis, Department of Soil  Science and Agricultural
 L-il clnl S T^2Ty •
 Journal of Environmental Quality, Vol. 7, No.1, p 84-86, January-March,  1978.
 1 fig,  1  tab, 21  ref.

 Descriptors:  Autoclaves,  Mercury, Volatility,  Microbial degradation, Soil
amendments, Montana.
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Five surface soils from southeastern Montana were studied to determine the
effects of autoclaving and glucose additions on the volatile loss of applied
divalent inorganic mercury.  Soils were amended to 1 ppm Hg as 203 Hg - Hg
(N03)2, maintained at room temperature near the 1/3-bar moisture content, and
Hg content monitored for seven weeks.  Mercury losses from soils receiving
neither autoclaving or glucose additions ranged from 5 to 30%.  In general,
autoclaving reduced the total quantity of Hg lost, while glucose additions
increased the initial loss rate of applied Hg.


78:02K-034
COPPER AND CADMIUM ADSORPTION CHARACTERISTICS OF SELECTED ACID AND CALCAREOUS
SOILS,
Cavallaro, N.,  and McBride, M.B.
Cornell University, Ithaca, New York, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 4, p 550-556, July-August,
1978.  9 fig, 2 tab, 27 ref.

Descriptors:  Heavy metals, Copper, Cadmium, Adsorption, Ion exchange, Acidic
soils, Calcareous soils, Soil chemistry, New York.

Samples of two New York soils, an acid and a neutral silt loam, were equilibrated
with Cu(2+) and Cd(2+) solutions in concentrations ranging from 0.00001 to 0.0001M
in distilled water and in 0.01M CaCl2.  The extent of complexation and adsorption
of the heavy metals was measured using specific ion electrodes and atomic absorp-
tion.  The data were found to fit the Langmuir adsorption model, and the Cu(2+)
adsorption maxima were greater than those of Cd(2+) for both soils.  Acid soils
demonstrated much less ability to retain the heavy metals than neutral soils.
In the presence of 0.01M CaCl2, adsorption of the metals was much reduced, suggest-
ing Ca(2+) competition for adsorption sites.  A considerable amount of Cu(2+)
was complexed in the soil solutions, but Cd(2+) complexation was much less evident.
The results support an ion exchange mechanism of adsorption in the surface soils,
arid suggest that precipitation occurs in calcareous subsoils.


78:02K-035
THERMODYNAMICS OF POTASSIUM-CALCIUM AND MAGNESIUM-CALCIUM EXCHANGE REACTIONS ON A
KAOLINITIC SOIL CLAY,
Udo, E.J.
Ibadan University, Nigeria, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 4, p 556-560, July-August,
1978.  2 fig, 3 tab, 22 ref, 15 equ.

Descriptors:  Thermodynamics, Cation exchange, Kaolinite, Potassium, Calcium,
Magnesium, Adsorption, Isotherms, Selectivity, Soil profiles.

Thermodynamic parameters derived from experimental results were determined for the
potassium-calcium and magnesium-calcium exchange reactions on a kaolinitic soil
clay separated from the B horizon of a strongly weathered soil Profile.  The clay
samples were equilibrated at 10 and 30 C with a mixed solution of KCl and CaC12
for the K-Ca system or MgCl2 and CaCl2 for the Mg-Ca system.  For the K-Ca system,
the selectivity coefficients were high indicating a greater affinity of the clay
for K than for Ca.  The high equilibrium constant and the negative values of
standard free energy and enthalpy changes for the exchange of Ca for K also revealed
a preference of the clay for K relative to Ca ions.  In the Mg-Ca system, the
exchange isotherms and the low selectivity coefficients indicated a preference of
Ca ions for the clay phase.  This exchange of Ca for Mg was accompanied by an in-
crease in the free energy and enthalpy changes also pointing to a more stable Ca-
clay than Mg-clay.


78:02K-036
PREDICTION OF PHOSPHORUS DIFFUSION FROM FERTILIZER SOURCE,
Hira, G.S., and Singh, N.T.                   .                   .,
Punjab Agricultural University, Ludhiana, India, Department of Soils.
Soil science Society of America Journal, Vol. 42, No. 4, p 561-565, July-August,
1978.  7 fig, 2 tab, 11 ref, 11 equ.

Descriptors:  Phosphorus, Diffusion, Fertilization, Diffusivity, Adsorption,
Isotherms, Soil chemistry.


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Rate of P diffusion from fertilizer applied at the soil surface was studied using
Pick's law of diffusion.  The diffusion coefficient of P was determined from a
knowledge of the tortuosity factor and P adsorption isotherm.  Phosphorus diffu-
sion coefficient calculated from Nye's equation did not prove suitable at very
low or high concentration of P at the soil surface.  The phosphorus diffusion
coefficient calculated from experimental data increased linearly with the square
root of P concentration applied at the source.  Predicted P concentration-distance
profiles were very close to the experimental values estimated by employing a
sectioning technique.


78:02K-037
PHOSPHATE DESORPTION FROM KAOLINITE SUSPENSIONS,
Bar-Yosef, B., and Kafkafi, U.
Division of Soil Chemistry and Plant Nutrition, Bet Dagan, Israel, The Volcani
Center.
Soil Science Society of America Journal, Vol. 42, No. 4, p 570-574, July-August,
1978.  5 fig, 2 tab, 18 ref, 2 equ.

Descriptors:  Phosphates, Kaolinite, Activation energy, Hysteresis.

The objective of this work was to study the effect of the .desorption method used,
equilibration time and the dissolved silica on the desorption of P from kaolinite.
Two desorption methods were used:  (i) diluting 1% suspensions by various volumes
of the same electrolyte,-arid (ii) immersing a dialysis tube containing 0.25%
suspension (+P) in an identical suspension initially free of P.  The desorption
process in both cases could be divided into a rapid and a slow first-order
reaction.  The rapid reaction rate constant was similar in both systems (about
4.65 x 0.001/hour at 25 C).  The slow reaction constants were 0.3 x 0.001/hour and
1.15 x 0.001/hour for cases (i)  and (ii) , respectively.  The activation energy of
the desorption process in case (ii) was 16.2 Kcal/mole for the rapid and 4.8 Real/
mole for the slow reaction.  The amount of silica dissolved from kaolinite due to
dilution with 0.01M KC1 depended on the dilution ratio and reached 16 mg SiO2/g
kaolinite when the suspension was diluted 100-fold.  Readsorption of part of the
dissolved silica is stipulated to contribute to the fast P desorption process.


78:02K-038
FACTORS AFFECTING DENITRIFICATION IN A SONORAN DESERT SOIL,
Westerman, R.L., and Tucker, T.C.
Oklahoma State University,  Stillwater, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 4, p 596-599, July-August,
1978.  4 fig, 3 tab, 6 ref.
                     «
Descriptors:  Denitrification, Nitrogen, Temperature, Moisture content, Time, Arid
climates, Deserts, Carbon,  Depth.                  ',

Incubation studies were conducted to determine the effect of temperature, moisture
content, organic C, soil depth,  and time on transformations of added 15NO3(-N) to
a Sonoran Desert soil in open and closed systems.  In open system studies, increasing
temperature from 20 to 37 C, adding organic C, and increasing moisture content from
field capacity to saturation increased denitrification losses 16, 22, and 2%,
respectively.  There were no apparent differences in immobilization of 15N03(-N)
due to temperature, time, moisture content, or soil depth without organic C'amend-
ments.  However, immobilization of 15N03C-N)  soil with organic C amendments was
increased markedly with increased temperature and time, but initial moisture con-
tent had little effect.  At C/N ratios of 150:1 only traces of 15N appeared in
NH4(-N), however, at C/N ratios of 15:1 to 45:1 ammonification and immobilization
occurred simultaneously.  Closed system investigations with organic C and 15N03(-N)
amendments showed 79% loss in five days with the remaining 21% accumulating as
organic-15N.  Denitrification losses in open systems with soil moisture contents
representative of saturated conditions were 70% of the loss observed under closed
systems at the same moisture content.
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 78:02K-039
 SURFACE CHARGE MANIPULATION OF CONSTANT SURFACE POTENTIAL SOIL COLLOIDS:  I
 RELATION TO SORBED PHOSPHORUS,
 Warm, S.S., and Uehara, G.
 Hawaii University, Honolulu, Department of Agronomy and Soil Science.
 Soil Science Society of America Journal, Vol. 42, No. 4, p 565-570, July-August
 1978.  7 fig, 4 tab, 20 ref, 7 equ.

 Descriptors:  Colloids, Phosphorus, Cation adsorption, Cation exchange, Soil
 management, Soil chemistry.

 A significant correlation was found between the zero point of charge and the
 quantity of phosphorus applied to soil material from an Oxisol.   Sorbed phosphorus
 lowered the zero point of charge and increased surface charge density at any pH
 above the zero point of charge.  The soil was treated with 0, 100,  500, and 1,500
 Ppm P as (NH4J2HPO4.    For the soil with no added phosphorus, low concentration
 of monovalent electrolyte and within two pH units of the zero point of charge,
 diffuse layer theory adequately predicted surface charge.   For high electrolyte
 concentration and high pH, the Stern theory with specific adsorption energy
 predicted the experimental results.  The calculated results indicated charge
 reversal in the high-phosphorus samples.


 78:02K-040
 EFFECTS OF  SOLUTION CHEMISTRY AND ENVIRONMENTAL CONDITIONS ON AMMONIA VOLATILIZATION
 LOSSES FROM AQUEOUS SYSTEMS,
 Vlek,  P.L.G.,  and Stumpe,  J.M.
 International Fertilizer Development Center,  Florence, Alabama, Agro-Economic
 Division.
 Soil Science Society of America Journal, Vol.  42,  No.  3,  p 416-421,  May-June, 1978.
 5  fig,  1 tab,  17 ref,  7 equ.

 Descriptors:   Nitrogen, Ammonia,  Volatility,  Rice,  Fertilization, Aqueous  solutions,
 Kinetics.

 Laboratory  studies were conducted to explain the wide  variation in  reported  esti-
 mates  of ammonia volatilization losses from N-fertilized paddy fields.   The  ammonia
 volatilization capacity of a system was found  to be equivalent to its  alkalinity.
 In solutions  lacking  alkalinity,  loss of (NH4)2SO4  was limited, whereas  loss  of
 (NH4)2C03 was  essentially  complete.   Ammonia  loss  from solution is best  described
 as a consecutive reaction  with  opposing step.   Ammonia volatilization  per  se
 followed first-order  reaction kinetics.   The rate of ammonia  volatilization was
 severely restricted by  limiting the movement of air above  the water, as  is often
 the case in the  laboratory and  field studies reported  to date.  Ammonia  volatili-
 zation was  enhanced by  water turbulence and increased  exponentially with temperature
 from almost nil  at 0  C  to  approximately 20  mg N/100 sq cm/5 hours at 46  C.


 78:02K-041
 CALCIUM-SUPPLYING  CHARACTERISTICS OF TWO GYPSUM MATERIALS ON  SOUTHEASTERN COASTAL
 PLAIN SOILS,
 Keisling, T.C.,  and Walker,  M.E.
 Texas A  & M University, Overton, Agricultural Research and Extension Center.
 Soil Science Society of America Journal, Vol. 42, No.  3, p 513-517, May-June, 1978.
 2  fig, 2 tab,  16 ref.

 Descriptors:   Gypsum, Calcium sulfate, Peanuts,  Granules, Leaching, Particle size,
 Coastal plains.

 Field studies were  conducted on two  soils to study  the manner in which finely and
 coarsely divided gypsum materials supplied Ca to the soil depth where peanut
 (Arachis hypogaea L.) fruit  absorb Ca.  The finely divided material was charac-
 terized chemically  as CaS04-2H20, approximately  72% CaS04 or  20.2% Ca and physically
 as having 88% of the particles < 0.25 mm in diameter.  The coarsely divided material
was characterized chemically as CaSOR, approximately 92% CaS04 or 26.5% Ca and
Physically as having 82% with particle diameters <  4.2 mm, but >  0.5 mm.  The
amount of Ca transported to a given soil depth was found to be related to the
n^agnitude, order, and frequency of rainfall events.  The fine gypsum material was
found to be more effective in supplying Ca to the soil depth where peanut fruit


                                      97

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are absorbing  it early  in the growing  season than the coarser material.  Dissolu-
tion of gypsum sources  consisting of different particle sizes and subsequent
transport of Ca into the fruiting zone of peanuts was not always closely related
to the total amount of  rainfall.  Either the finely or coarsely divided gypsum
could supply more Ca to the fruiting zone depending on the rainfall pattern.


78:02K-042
COMETABOLISM OF FOREIGN COMPOUNDS,
Golovleva, L.A., and Skryabin, G.K.
Institute of Biochemistry and Physiology of Microorganisms.
In:  Symposium on Environmental Transport and Transformation of Pesticides,
October, 1976, Tbilis,  USSR.  EPA-600/9-78-003, February, 1978, Athens, Georgia,
P 73-85.  6 fig, 11 ref.

Descriptors:   Microbial degradation, Soil microbiology, Microorganism, Soil
microorganism, Herbicides, Chemical degradation, Environmental control.

The fermentative conversions of many organic substances are closely connected or
even depend on oxidation of other compounds—cosubstrates.  This dependence is
generally called cometabolism.  The best known are the cometabolism processes of
foreign compounds—xenobiotics, though there are also the examples of cometabolism
of natural compounds for instance steroids and terpenes as well as such substrates
as xylose, widely spread in nature and easily metabolized.  The investigations
conducted by the authors proved that conversions of many xenobiotics are possible
only under cometabolism conditions.  The experiments with introduction of micro-
organisms into natural  water reservoirs did not give positive results.  However,
the degradation of herbicides was significantly accelerated after introducing
cosubstrates.  So, analysis of 2,4-D dynamics in waste waters of rice fields has
shown that 2,4-D disappeared more quickly if propionate was used as cosubstrate.
In this case,  the herbicide was not detected in the water in three days; at the
same time, about 25% of initial 2,4-D  was present in control experiments (without
propionate).


78:02K-043
AMMONIA VOLATILIZATION  LOSSES FROM FLOODED RICE SOILS,
Mikkelsen, D.S., De Datta, S.K., and Obsemea, W.N.
The International Rice  Research Institute, Los Banos, Laguna, Department of
Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 5, p 725-730, September-
October, 1978.  8 fig,  10 ref.
                   K
Descriptors:   Nitrogen, Volatility, Hydrogen ion concentration, Diurnal, Ammonia,
Submerged plants, Fertilization.

The pH of the  flood water in rice fields is largely determined by the chemical
equilibria that exist between the C02  balance achieved by the aquatic biota and
the various solutes, solids, and gases in the water.  Water pH values undergo
diurnal changes increasing by midday to values as high as pH 9.5-10 and decreasing
as much as 2-3 pH units during the night.  The pH of shallow flood water is greatly
affected by the total respiration activity of all the heterotrophic organisms and
the gross photosynthesis of the species present.  Ammonium from fertilizers broad-
cast into a high pH water are highly susceptible to direct NH3 volatilization
losses.  Nitrogen losses from fertilizer broadcast into flood water on a fertile,
neutral-pH Maahas clay  were as high as 20% of the amount applied, but losses varied
depending upon water pH, the nitrogen  source, rate, time, and method of applica-
tion.  Losses  from an acid Luisiana clay, where the flood water was not conducive
to algal growth and did not exceed pH  6.8, produced NH3 volatilization losses
consistently less than  1% of the total N applied.  Placement of N fertilizer in
the soil at depths of 10-12 cm reduced NH3 volatilization losses to less than
1% of the total N applied.


78:02K-044
CHEMISTRY OF SNOW MELTWATER:  CHANGES  IN CONCENTRATION DURING MELTING,
Johannessen, M., and Henriksen, A.
Norsk Institute for Vannforskning, Blindern.
Water Resources Research, Vol. 14, No.  4, p 615-619, August, 1978.  7 fig,  4 tab,'
12 ref.


                                       98

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Descriptors:  *Snow, *Snowmelt, *Melt water, *Water chemistry, Laboratory tests,
On-site investigations, Lysimeters, Snowpacks, Hydrogen ion concentration, Acids.

Over much of Norway a large portion of the yearly precipitation falls as snow,
and the pollutants contained in precipitation accumulate in the snowpack to be
released during a short period in spring.  Atmospheric fallout of sulfur com-
pounds has been estimated to be about 30% of the total deposition in Norway, but
fallout on the snow cover is probably considerably smaller.  During winters with
little or not snowmelt before spring, most of the pollutant load is retained in
the snowpack.  Laboratory and field lysimeter experiments indicated that 5-80%
of the pollutant load is released with the first 30% of the meltwater.  The
average concentration of pollutants in this fraction is 2-2.5 times the concen-
tration in the snowpack itself.  The very first fractions may contain more than
5 times the snowpack itself.  These high concentrations may be due to a freeze-
concentration process during snow recrystallization and melting in which contami-
nants accumulate preferentially at the surfaces of ice particles.  The resulting
increase in the acid concentration of low-buffered water courses occassionally
leads to social physiological stress to fish and other aquatic organisms and even
to massive fish kills.  This process occurs at a time which is critical to the
hatching stage of salmonid fish species.


78:02K-045
ELECTRON PROBE MICROANALYSIS OF CALCITE GRAINS CONTAINING PHOSPHORUS IN SOIL,
Qureshi, R.H., and Jenkins, D.A.
Agricultural University, Lyallpur, Department of Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 5, p 703-705, September-
October, 1978.  4 fig, 11 ref.

Descriptors:  Calcite, Phosphorus, Chemical analysis. Soil tests, Nutrients,
Soil analysis, Analytical techniques.

Calcite, comprising both clastic sand-sized grains and fossil foraminifera
inherited from a marine Cretaceous (Gault)clay, was isolated from a haplaquept
(gleyic brown calcareous earth) in the United Kingdom and shown by wet chemical
analysis to contain an average of 0.3% phosphorus.  Electron probe microanalysis
indicated that this phosphorus is uniformly distributed within the calcite
rather than concentrated as discrete calcium phosphates, and it was concluded
that it was biogenic-diagenic rather than pedogenic in origin.  Such sources
were found to constitute 50-80% of the total soil phosphorus and thus suggested
to be relatively available in the upper horizons of the profile.


78:02K-046
THE SPECTROPHOTOMETRIC AND FLUOROMETRIC DETERMINATION OF ALUMINUM WITH 8-
HYDROXYGUINOLINE AND BUTYL ACETATE EXTRACTION,
Bloom, P.R., Weaver, R.M. , and McBride, M.B.
Minnesota University, St. Paul, Department of Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 5, p 713-716, September-
October, 1978.  2 fig, 3 tab, 11 ref.
(See: 78S07B-018)


78:02K-047
CATION EXCHANGE EQUILIBRIA IN A MIXED SOIL SYSTEM CONTAINING THREE HETEROVALENT
CATIONS ,
Wiedenfeld, R.P., and Hossner, L.R.                             .
Texas Agricultural Experiment Station, Weslaco, Department of Soil and Crop
   .
Soil Science Society of America Journal, Vol. 42, No. 5, p 709-712, September-
October, 1978.  4 fig, 1 tab, 12 ref, 15 equ.

Descriptors:  Cation exchange, Cations, Chemical reactions, Thermodynamic
behavior, Equilibrium, Calcium, Magnesium, Sodium.

Cation exchange equations used with soils have been suitable only for systems
containing two cations.  Theoretical exchange equilibria relationships for a
mixed soil system containing three heterovalent cations: Ca(2+>, Mg(2+), and
Na(+); were presented.  Predictive equations for this tertiary system were derived
                                                                      i,

                                      99

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 using  solid  phase  activity  coefficients  and thermodynamic equilibrium constants
 for  the  three  binary  systems obtained  from experimental data.  Theoretical
 cation exchange  equilibria  described for this  tertiary system were  in agreement
 with recognized  exchange properties for  these  three cations.  Interactions between
 two  cations  as they affect  the exchange  behavior of a third cation  were also
 predicted.   The  methods presented are  applicable to systems containing any
 number of heterovalent cations.


 78:02K-048
 TEMPERATURE  AND  pH AS LIMITING FACTORS IN LOSS OF NITRATE FROM SATURATED ATLANTIC
 COASTAL  PLAIN  SOILS,
 Gilliam, J.W., and Gambrell, R.P.
 North  Carolina State  University, Raleigh, Department of Soil Science.
 Journal  of Environmental Quality, Vol. 7, No.  4, p 526-532, October-December,
 1978.  5 fig,  2  tab,  35 ref.

 Descriptors:   Nitrates, Reduction (chemical),  Denitrification, Nitrogen, Water
 pollution, Groundwater, Atlantic Coastal  Plain.

 Nitrate  reduction  rates under water-saturated  conditions were determined for two
 acid Atlantic  Coastal 'Plain topsoils and their acid subsoils at 5,  15, and 25 C.
 Nitrate  reduction  readily occurred in  subsoils even at pH values of 4.5 when an
 energy source  was  added.  It was concluded that the acid pH values which commonly
 occur  in Atlantic  Coastal Plain soils  is  not a serious limiting factor in NO3(-)
 reduction.   It was also concluded that the temperatures of 5 to 15  C which exist
 in the shallow groundwater  of the Atlantic Coastal Plain soils during much of
 the  winter limits  the .rate  of N03(-) reduction and nitrate reduction can occur
 in these soils at  5 C but the rate is  relatively slow and is highly dependent
 upon the amount  of available C.  A significant amount of NO3(-) reduction was
 expected during  the winter  in poorly drained soils which contain relatively high
 organic  matter contents.


 78:02K-049
 METABOLISM OF  NITROPHENOLS  IN FLOODED  SOILS,
 Sudhakar-Barik,  and Sethunathan, N.
 Central  Rice Research Institute, Cuttack-753006, India, Laboratory of Soil
 Microbiology.
 Journal of Environmental Quality, Vol.  7, No.  3, p 349-352, July-September, 1978.
 4 tab, 12 ref.

 Descriptors:  Orgdnophosphorus compounds, Flooding, Water pollution, Nitrites,
 Isotope  studies,  Pollutants.

 Nitrophenols (p-,0-> and m-isomers and 2,4-dinitrophenol)  disappeared fairly rapidly
 from flooded alluvial and organic matter-rich acid sulfate (pokkali) soils inoc-
 ulated with parathion (0,0-diethyl 0,p-nitrophenyl phosphorothioate)-enrichment
 cultures from the  respective soils.   Nitrite,  one of the reported end-products of
 nitrophenol  (0,0-dimethyl 0,p-nitrophenyl phosphorothioate)  metabolism, accumulated
 only in inoculated alluvial soil, irrespective of the type of nitrophenol added.
 In an  isotope study, ring cleavage of p-nitrophenol leading to carbon dioxide
was  demonstrated in flooded soils inoculated with parathion-enrichment culture,
particularly under stirred conditions.   Nitrophenols decomposed also in uninoculated
 samples of both soil types,  though slowly as compared to inoculated soils;  but
nitrite and carbon dioxide were not formed.   Resting cells of a bacterium,'
Pseudomonas sp. ATCC 29353,  readily hydrolyzed parathion and then liberated nitrite  .
 from p-nitrophenol.  In cell-free suspension,  the reaction ceased at the p-nitropheno1
 stage.   In bacterial cultures,  parathion was hydrolyzed without proliferation while
subsequent degradation of p-nitrophenol involved metabolism leading to bacterial
enrichment.


 78:02K-050
CATION-EXCHANGE CAPACITY OF CLAY-RICH SOILS  IN RELATION TO ORGANIC MATTER,  MINERAL
COMPOSITION,  AND SURFACE AREA,
Martel, Y.A., De Kimpe,  C.R.,  and Laverdiere,  M.R.
Agriculture Canada, 2560 chemin Gomin,  Sainte-Foy,  Quebec, GIV 2J3, Canada.
Soil Science Society of America Journal,  Vol.  42, No.  5,  p 764-767, September-
October,  1978.   1 fig, 7 tab,  16 ref.

                                     100

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Descriptors:  Cation exchange, Clay minerals, Clays, Organic matter, Minerology,
Soil horizons, Regression analysis, Soil texture.

Regression analyses were used to correlate organic matter, texture and surface
area values to the cation-exchange capacity (CEC) or clay-rich soils in the low-
lands of Quebec.  The Ap, Bg and Cg horizons of 11 Gleysolic soils (Agu-Suborders)
were analyzed for CEC, exchangeable bases and acidity, total and fine clay contents,
organic matter, surface area and mineralogical composition.  The soils contained
illite, chlorite, smectite, and vermiculite in addition to quartz and feldspars.
In the Ap horizon, total clay and fine clay contents were better related to CEC
than organic matter and surface area.  In the Bg and Cg horizons, surface area
gave the best correlation with CEC.  As calculated by multiple regression equa-
tions, CEC values of organic matter increased with depth from 56.5 to 223 meq/
100 g, while CEC values of total clay decreased from 37.7 to 22.5 meq/100 g and
that of fine clay decreased from 57.5 to 50.7 meq/100 g.  Variations in the
mineralogical composition, although small, were sufficient to explain nearly 50%
of the variations in the CEC.


78:02K-051
ADSORPTION AND EXTRACTABILITY OF MOLYBDENUM IN RELATION TO SOME CHEMICAL PROPERTIES
OF SOIL,
Karimian, N., and Cox,F.R.
Pahlavi University, Shiraz, Iran, College of Agriculture, Department of Soil
Science.
Soil Science Society of America Journal, Vol. 42, No. 5, p 757-761, September-
October, 1978.  3 fig, 4 tab, 32 ref.

Descriptors:  Molybdenum, Adsorption, Soil chemical properties, Soil tests,
Iron oxides, Organic matter, Hydrogen ion concentration, Phosphorus.

Adsorption of Mo from aqueous solutions was determined for eight soils from the
Atlantic Coastal Plain and Piedmont regions.  The data followed the Freundlich
isotherm more consistently than the Langmuir.  Adsorption increased as the organic
matter and/or Fe oxide contents of the soils increased.  Adsorption from an
aqueous solution that was initially 0.3 mM Mo (AdMo) also was determined on 32
soils collected from the regions.  The AdMo level was positively correlated with
Fe oxide and organic matter contents and negatively correlated with pH and P
levels.  The level of Mo extracted with acid ammonium oxalate (Grigg Mo)  and an
anion exchange resin (resin Mo) were also determined and related to soil chemical
properties and a lime treatment.  Grigg Mo was positively correlated with amor-
phous and free Fe oxide by oxalate.  Resin Mo was positively correlated with pH
but not with other soil properties.  Incubating soils with CaC03 increased the
level of resin Mo.


78:02K-052
CHEMICAL CHARACTERIZATION OF THE GASEOUS AND LIQUID ENVIRONMENTS OF SUBSURFACE
DRAIN SYSTEMS,
Meek, B.D., Grass, L.B., and MacKenzie, A.J.
Imperial Valley Conservation Research Center, Brawley, California.
Soil Science Society of America Journal, Vol. 42, No. 5, p 693-698, September-
October, 1978.  3 fig, 6 tab, 14 ref.

Descriptors:  Chemical precipitation, Subsurface drains, Subsurface drainage,
Aeration, Iron, Manganese, Oxygen, Drainage water, Oxidation, Reduction (chemical).

Chemical composition of subsurface drain effluents was determined in the field as
a function of location (various depths and soil textures), entry point of the
solution into the drainpipe, and distance from outlet (with or without a water
trap).  Liquid samples were analyzed for Fe, Mn, NO3-N, HC03, organic carbon,
electrical conductivity, pH, and dissolved oxygen, and gas samples were analyzed
for 02 and C02.


78:02K-053
BIOLOGICAL HYDROLYSIS OF PARATHION IN NATURAL ECOSYSTEMS,
Sudhakar-Barik, and Sethunathan, N.
Central Rice Research Institute, Cuttack-753006, India, Laboratory of Soil
Microbiology.

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 Journal of Environmental Quality,  Vol.  7,  No.  3,  p 346-348,  July-September,
 1978.   5 tab,  11  ref.

 Descriptors:   Organophosphorus  compounds.  Flooding,  Hydrolysis, Water pollution.

 Parathion (0,0-diethyl  0,p-nitrophenyl  phosphorothioate) was applied to  flooded
 soils  and to water  and  sediment river,  lake, and  pond  samples at  15-day  intervals.
 While  p-nitrophenol (0,0-dimethyl  0,p-nitrophenyl phosphorothioate), the hydrolysis
 product of parathion, was not detected,  even at the  end of 12 days  after the  first
 addition,  it was  detected in all samples within 6 hours after two or three additions
 of  the insecticide.  Enrichment cultures from  the samples of different ecosystems
 lost their ability  to hydrolyze parathion  following  autoclaving,  suggesting micro-
 bial participation  in parathion hydrolysis.


 78:02K-054
 EXTRACTABILITY OF CADMIUM, COPPER, NICKEL, AND ZINC  BY DOUBLE ACID  VERSUS DTPA
 AND PLANT CONTENT AT EXCESSIVE  SOIL LEVELS,
 Korcak,  R.F.,  and Fanning, D.S.
 United States  Department of Agriculture, Science  and Education Administration,
 Fruit  Laboratory, Beltsville Agricultural  Research Center-West, Beltsville,
 Maryland.
 Journal of Environmental Quality,  Vol.  7,  No.  4,  p 506-512,  October-December, 1978.
 1 fig,  9 tab,  18  ref.
 (See 78:021-032)


 78:02K-055
 INFLUENCE  OF THE  CHEMICAL FORM  OF  MERCURY  ON ITS  ADSORPTION  AND ABILITY  TO LEACH
 THROUGH  SOILS,
 Hogg,  T.J., Stewart, J.W.B., and Bettany,  J.R.
 Saskatchewan University,  Saskatoon, Saskatchewan,  Canada, Institute of Pedology.
 Journal  of Environmental Quality,  Vol.  7,  No.  3,  p 440-445,  July-September, 1978.
 2 fig,  4  tab,  19  ref.

 Descriptors:   Mercury, Adsorption, Leaching, Volatility, Sewage effluents, Sewage
 disposal,  Irrigation, Soil analysis.

 The  adsorption of Hg by  two soils, differing in chemical and physical characteristic3'
 indicated  that both methyl mercuric chloride {MMC) and phnyl  mercuric  acetate  (PMA)
 and  mercuric chloride (HgC12)  followed the linear  form of the Langmuir adsorption
 isotherm.   The highest adsorption maxima for all Hg  compounds were  found for the
 soils which had the higher organic matter  content  and clay content.  Adsorption
 maxima  increased  in the  order MMC  < PMA  < HgC12.   A  two-rate effluent leaching
 experiment was conducted utilizing undisturbed soil  cores of the  same two soils and
 the  same three Hg compounds (labeled with  203Hg) which were  applied uniformly to
 the  top  0-10 cm  >f each  column.  In contrast to the movement of other cations in
 the  effluent and  soil, even at  the higher  irrigation rate, none of the applied Hg
 was  found  to move below  the 10-  to 20-cm soil  layer.  The lack of movement of
 Hg and the  high adsorption maxima was a consequence of the strong, binding between
 Hg compounds and  soil.   The inability of weak chemical extractants  (CaC12, NH40AC,
 DTPA, EDTA) to remove significant quantities of Hg confirmed this hypothesis.
 Seven to 31% of the applied Hg was lost from the columns during the experiment
 presumably by  volatilization.


 78:02K-056
 SEASONAL VARIATION IN PC02 AND  13C CONTENT OF SOIL ATMOSPHERE,
 Rightmire,  C.T.
 United States  Geologic Survey,  Idaho National Engineering Laboratory,  Idaho Falls.
Water Resources Research, Vol.  14,  No. 4, p 691-692, August,   1978.  1 fig, 9 ref,
 2 equ.

 Descriptors:   Soil gases, Soil environment, Carbon dioxide,  Seasonal,  Groundwater
 recharge, Artificial recharge.

 Soil carbon dioxide is the dominant source of dissolved inorganic carbon in
 recharging waters.  Samples of soil C02 were collected to determine if seasonal .
 variations  in  13C content parallel those previously observed  for PCO2.   Signifi-
 cant seasonal  variations  in both PC02 and 13C content were observed.  The data

                                     102

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presented  in this paper  indicated that the studies of groundwater carbonate
chemistry  require knowledge of the season during which major recharge occurs.


78:02K-057
LONG-TERM  DENITRIFICATION STUDIES IN SOILS FERTILIZED WITH  (15NH4)2S04(1),
Focht, D.D., and Stolzy, L.H.
California  University, Riverside, Department of Soil and Environmental Sciences.
Soil Science Society of  America Journal, Vol. 42, No. 6, p  894-898, November-
December,  1978.  6 fig,  1 tab, 31 ref, 3 egu.

Descriptors:  Denitrification, Nitrogen, Nitrates, Nitrogen cycle, Soil gases,
Air pollution, Lysimeters, Isotope studies, Fertilization.

A 2-year study was conducted in lysimeters containing four different soils with
successive  summer and winter crops of corn and barley, respectively.  The crops
were fertilized with (15NH4)2SO4 at application rates equivalent to 134, 108,
415, and 440 Kg N/ha for the respective summer 1973, winter 1974, summer 1974, and
winter 1975 crops.  The  frequency of 15N dinitrogen samples was higher in the
summer and high at the lower fertilizer rates, while the reverse was true for
NO3(-J concentrations in leach water and N20 concentrations in the soil profile.
Emissions of N20 from soil, even where the higher concentrations were observed,
were low in terms of N losses with the greatest mass emission at any time
amounting  to 6.5 g/ha over a 1-day period.  Nitrogen gas emissions over a 1-week
period in one instance were estimated at 5.2 kg N/ha:  it was observed that this
amount could be generated from low (1 ppm or less) concentrations of N20.


78:02K-058
EXCHANGE ADSORPTION OF TRACE QUANTITIES OF CADMIUM IN SOILS TREATED WITH CALCIUM
AND SODIUM:  A REAPPRAISAL,
Milberg, R.P., Brower, D.L., and Lagerwerff, J.V.
Agricultural Environmental Quality Institute, Beltsville Agricultural Research
Center, Beltsville, Maryland  20705.
Soil Science Society of America Journal, Vol. 42, No. 6, p 892-894, November-
December, 1978.  2 tab,  4 ref, 1 equ.

Descriptors:  Cation exchange, Cation adsorption, Cadmium, Calcium, Sodium,
Organic matter.

This paper presents a reevaluation and revision of the data on Ca-Cd and Na-Cd
exchange in three soils originally presented in an earlier paper (Lagerwerff
and Brower, Soil Sci. Am. Proc. 36:734-737).  Cadmium was selectively adsorbed
over Ca in Cecil, Winsum, and Yolo soils with up to 1.7% of the total cation
exchange capacity occupied by Cd.   Selectivity was greatest in Yolo and least
in Cecil.  Effects of undissociated Cd in solution were minor.   Separation
factors decreased with increasing exchangeable Cd.  Reexamination of Cd-Na
exchange revealed that anomalous earlier results were due to the dispersion
of organic matter during treatment with Na2CO3 in the preparation of Na-saturated
soils.  Na-Cd exchange was normal where organic matter loss was prevented.


78:02K-059
SERIOUS INTERFERENCES IN THE DETERMINATION OF TRACE METALS IN SOILS BY FLAME
AND FLAMELESS ATOMIC ABSORPTION SPECTROMETRY,
Mubarak,  A., Hageman, L., Howald,  R.A.,  and Woodriff, R.
Montana College of Mineral Science and Technology, Butte, Department of
Chemistry.
Soil Science Society of America Journal, Vol. 42, No. 6, p 889-891, November-
December, 1978.  5 tab, 14 ref.

Descriptors:  Trace elements, Spectrometers, Chemical analysis. Soil chemistry;
Absorption.

Negative interfering effects on the carbon rod atomizer (CRA)  absorbances of Mn,
Fe,  and Ni were found to occur in the presence of the chlorides of the major
cations (Ca, Mg,  Na)  in the soil solution.   These interferences were corrected
either by precipitation of the chlorides with silver nitrate or by incorporating
a relatively high level of sulfuric or nitric acid into the sample volume.


                                     103

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Magnesium ion,  irrespective of the associated anion, was found to lower the Cd
signal on the CRA.  High concentrations of MgSO4 caused lowering of the Mn
signal when using air-acetylene 'flame.  This lowering effect of MgS04 was
avoided  upon using N2O-acetylene  flame.  No interferences were noticed for Mn and
Zn when  using the constant temperature furnace developed at Montana State
University.


78:02K-060
SURFACE  CHARGE  MANIPULATION IN CONSTANT SURFACE POTENTIAL SOIL COLLOIDS:  II.
EFFECT ON SOLUTE TRANSPORT,
Wann, S.S., and Uehara, G.
Hawaii University, Honolulu, Department of Agronomy and Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 6, p 886-888, November-
December,  1978.  6 fig, 2 tab, 6  ref, 1 equ.

Descriptors:  Ion transport, Ion  exchange. Colloids, Nutrient removal, Potassium,
Phosphorus, Isotherms.

Potassium breakthrough curves from soil columns containing samples collected from
an oxic  horizon of a Typic Torrox shifted to the right as the sample was treated
with increasing levels of P.  The shift in the breakthrough curve was significantly
related  to a lowering of the zero point of charge.  The lowering of the zero
point of charge was in turn related to levels of applied P.  The anion accompanying
K also had a marked effect on the position of the breakthrough curve.  When
the accompanying anion was Cl, S, and P respectively, the K concentration in the
effluent attained one-half of influent concentration at 4.25, 5.30, and 8.20 pore
volumes.


78:02K-061
FIELD MEASUREMENT OF DENITRIFICATION:  I. FLUX OF N2 AND N2O,
Rolston,  D.E.,  Hoffman, D.L., and Toy, D.H.
California University, Davis, Department of Land, Air and Water Resources.
Soil Science Society of America Journal, Vol. 42, No. 6, p 863-869, November-
December,  1978.  7 fig, 3 tab, 16 ref, 3 equ.

Descriptors:  Denitrification, Nitrogen, Nitrogen cycle, Measurement, Soil gases,
Diffusion, Soil moisture, Soil temperature. Water pollution.
                  •
The objective of the research reported in this paper was to measure denitrificatibn
in a field soil directly from the fluxes of N2 and N2O at the soil surface at a
high and low soil temperature, at two water contents near saturation, and at three
levels of  C input (cropped, uncropped, and manure).  The research was conducted
on small one-m2 field plots because of the large cost of N03(-) fertilizer tagged
with high  enrichments of 15N.


78:02K-062
DETERMINATION OF THE APPARENT DISPERSION COEFFICIENT OF.SOLUTES IN UNSATURATED
SOIL,
Paetzold,  R.F., and Scott, H.D.
United States Department of Agriculture, Soil Conservation Service, National Soil
Survey Laboratory, Lincoln, Nebraska  68508.
Soil Science Society of America Journal, Vol.  42, No. 6,  p 874-877, November-
December,  1978.  3 fig, 1 tab, 14 ref, 16 equ.

Descriptors:  Dispersion, Solutes, Diffusion,  Convection,  Unsaturated flow,
Radioisotopes, Pesticides, Herbicides, Soil chemistry.

A method for determining the apparent dispersion coefficient of a solute in
unsaturated soils at relatively low soil water flow rates  was presented.   Two
soil cores with different initial water contents were joined and water allowed to
flow between the soil cores for a specified time interval.   The distribution of
a radioactively tagged solute, initially present in one of the soil cores, was
subsequently determined by freezing the cores  in liquid air,  sectioning the soil •
with a refrigerated microtome, and analyzing the soil sections for solute content
using liquid scintillation techniques.  Apparent dispersion coefficients could-be
determined either with or against the water, flow.  The solutes used in this study
were tritiated water, chloride, and metribuzin (a herbicide).

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 78:02K-063
 A UNIVERSAL DIMENSIONLESS PHOSPHATE ADSORPTION ISOTHERM FOR SOIL,
 Shayan,  A., and Davey,  B.C.
 Arya-Mehr University of Technology, Isfahan,  Iran.
 Soil Science Society of America Journal,  Vol.  42, No.  6,  p 878-882,  November-
 December, 1978.  3 fig, 1 tab, 20 ref,  5  equ.

 Descriptors:  Adsorption, Phosphates,  Isotherms, Kaolinite, Chemical potential,
 Fertilizers, Soil chemistry.

 A unique dimensionless  phosphate adsorption isotherm,  covering the solution
 concentration range 0.000001  to 0.1M P, which  has been found to fit  17  materials
 including 15 soils, pure kaolinite and  amorphous Al(OH)3,  was derived.   The soils
 shown to fit the isotherm included chronic luvisols, pellic vertisols,  calcic
 luvisols, a tropeptic eutrorthox, a volcanic ash soil  from New Zealand,  and a
 number of English soils.  The necessary parameters  to  derive  a complete adsorp-
 tion isotherm for a particular soil from the  universal isotherm,  required  three
 adsorption experiments  in the high concentration range (0.000001 to  0.0001H P)
 to define the linear portion  of the isotherm and the critical concentration.
 Three other determinations in the range 0.000001 to 0.0001N P were needed to ob-
 tain the areundlich isotherm  from the data after correction, for the  effect  of the
 linear region of the isotherm at high concentration.   The  advantage  of  this
 universal isotherm over conventional isotherms, is  that it requires  less experi-
 mental work to define and is  applicable over a wide range  of P concentrations
 such as  might be found  surrounding a fertilizer granule.


 78:02K-064
 CHLORIDE AS A FACTOR IN MOBILITIES OF Ni{II),  Cu(II),  AND  Cd(II) IN  SOIL,
 Doner, H.E.
 California University,  Berkeley,  Department of Soils and Plant Nutrition.
 Soil Science Society of America Journal,  Vol.  42, No.  6, p 882-885,  November-
 December,  1978.   5 fig,  3 tab,  15 ref,  4  equ.

 Descriptors:   Trace elements/  Metals, Chlorides, Adsorption,  Ion transport,
 Leachate,  Chemical analysis,  Soil analysis, Water pollution.  Laboratory  tests.

 An investigation was undertaken to study  the mobility  of chloro-complexes of
 Ni(ii),  Cu(II),  and Cd(II) through soil.   Soil columns were leached  with 0.1,
 0.2,  0.3,  or 0.5M  NaCl  or CaC104  solutions, each containing 10 microgram/ml
 Ni(ii),  Cu(II),  or Cd(II).  Sodium perchlorate solutions were  used as a  compari-
 son with CaCl at the same ionic strength  since perchlorate is  not  considered  to
 form complexes with the metals.   Leachates  from columns and soils were collected
 and analyzed.  Mobility of all  metals tested in chloride solutions was from 1.1
 to 4  times greater than that  in C104(-) solution.   Chloride  increased the
 mobility of Cd(II)  the  most which corresponds  to its having  the  largest  stability
 constants.   Copper (II)   was slowest to appear  in the leachate and was strongest
 adsorbed as evidenced by analysis of soil by digestion with  either 4N HN03 or
 acidified  NH20H-HC1.  These results  showed  that Cl(-)   has  a marked effect on  the
 mobility of Cd(II)  and,  to a  lesser extent, Ni(II)   and Cu(II).


 78:02K-065
 A  KINETIC  STUDY  OF THE  CaCO3 PRECIPITATION REACTION,
 Gilmour, J.T., Shirk, K.S., Ferguson, J.A., and Griffis, C.L.
 Arkansas University,  Fayetteville,  Department  of Agronomy.
 Agricultural Hater Management, Vol.  1, No. 3,  p 253-262, November,  1978.  2 fig,
 4  tab, 10  ref, 5 equ.

 Descriptors:  Chemical precipitation, Chemical reactions. Soil chemistry,
 Calcium  carbonate,  Magnesium carbonate. Kinetics, Water management (applied),
 Mathematical models,  Rice.

 In order to develop water management practices which would minimize localized
 precipitation of Ca  and Mg carbonates on Arkansas'  rice fields, a description
 of  the precipitation reaction was needed.   Waters studied were prepared solutions
which contained varying amounts of Ca(HCO3)2, Mg
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 order kinetics  where Ca was  the  rate  determining  ion.  An  empirical equation
 was  developed which showed that  the rate  constant could be calculated  from
 temperature and solution composition  data.  An  evaluation  of  the rates of Ca and
 Mg loss  from solution for the  experimental periods studied showed  that Mg losses
 were small  when compared to  Ca losses.


 78:02K-066
 THE  NITROGEN-15 ABUNDANCE IN A WIDE VARIETY OP  SOILS,
 Shearer,  G.,  Kohl,  D.H.,  and Chien, S-H.
 Washington  University,  St. Louis, Missouri, Center for the Biology of Natural
 Systems.
 Soil Science  Society of America  Journal,  Vol. 42,  No. 6, p 899-902, November-
 December, 1978.   1  fig,  6 tab, 13 ref,  2  equ.

 Descriptors:  Nitrogen,  Soil chemical properties,  Fertilizers, Environment,
 Soil chemistry,  Sampling, Correlation analysis.

 One  hundred thirty-nine soil samples from 20 states were analyzed for 15N
 abundance.  Soil characteristics and environmental conditions at the sampling
 sites  varied  widely.  The total N of surface soil  samples  had a mean delta 15N
 value  (per  mill 15N excess)  slightly but  significantly higher than the mean
 value  for soils collected from deeper layers, although the  relationship between
 delta  15N and soil  depth  was not consistent from  location  to location.  Differences
 among  mean  delta 15N values  for the total N of  soil samples collected from crop-
 land,  pasture,  uncultivated  land (with  native herbs), and  forest were not
 striking.   There was no  systematic effect of variation in  the rate of application
 of N fertilizer on  the  delta 15N of the total N of soils.   The mean delta 15N
 value  of surface soils, with respect to atmospheric N, was  +9.22 and the
 standard deviation  was  2.10  delta 15N units.  The  range within which 90% of the
 samples fell  was  +5.1 to  +12.3 delta 15N  units.  Less than  half of the variation
 among  the soils  in  delta  15N of the total N could  be accounted for by differences
 in environmental variables or soil characteristics.


 78:02K-067
 NITROGEN MINERALIZATION AND  DENITRIFICATION IN  ORGANIC SOILS,
 Guthrie, T.F.,  and  Duxbury,  J.M.
 Cornell University,  Ithaca,  New York, Department of Soil Organic Chemistry.
 Soil Science  Society of America Journal, Vol. 42,  No. 6, p  908-912, November-
 December, 1978.   1  fig,  6 tab, 13 ref.

 Descriptors:  Nitrogen, Denitrification, Organic soils. Nitrates, Leachate,
 Laboratory  tests.

 The quantities  of N mineralized when columns of Histosols were incubated at field
 capacity for  period  up to 28 days corresponded  to  500-600 kg N/ha per year without
 correction  for N lost by denitrification.   An absorption train utilizing molecular
 sieve  5A to collect N2O was  used in denitrification experiments.   Under an argon
 stream, 52-53% of the added NO3(-)-N was recovered as N2O,  whereas the maximum
 concentration of N20 accumulating in the headspace of closed vessels amounted to
 65% of the  added N03(-)-N.   The quantity of N2O either collected or accumulating
 in a headspace was  reduced to 15-41% of the N03(-)-N denitrified when a second
 addition of N03(-) was made  to the soils.   Denitrification occurred in both drained
 and flooded soil columns amended with N03(-).   The N20 recovered ranged from 2.5-
 9% and 9-19% of the N03(-)-N denitrified in the drained and flooded columns,
 respectively.' From 78-98% of the N2O was  recovered in leachate from the flooded
 columns and the corresponding range for the drained columns was 11-52%.


 78:02K-068
NITRATE REDUCTION TO AMMONIUM IN  ANAEROBIC SOIL,
Buresh, R.J., and Patrick, W.H.
Louisiana State University,  Baton Rouge, Center for Wetland Resources.
Soil Science Society of America Journal, Vol.  42, No.  6,-p 913-918, November-
 December, 1978.   3 fig, 3 tab,  32 ref.

Descriptors:  Nitrates, Reduction (chemical),  Anaerobic conditions, Denitrifica-
 tion, Nitrogen,  Oxidation-reduction potential.  Soil chemistry.


                                      106

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The objectives of  this  study were:   (i)  to compare the influence of various C
substrates  upon  the extent of NO3(-) reduction to NH4(+) relative to denitrifi-
cation  in anaerobic soil, and  (ii)  to determine the significance of NO3(-)
conversion  to NH4(+) and organic N  in unamended anaerobic soil.  Ammonium
accumulates by way of mineralization under anaerobic conditions, consequently
15N-labelled N03(-) was employed to distinguish between soil and NO3{-) -derived
NH4(+).  It was  concluded that transformation of significant amounts of N03(-)
to NH4(+) and organic N required intensely reduced soil conditions.  The reaction
was apparently not suppressed by NH4(+).  Evidence indicated that NO3(-) was
reduced to  NH4(+)  by a nonassimilatory pathway in which NO3(-) functioned as a
terminal electron  acceptor.


78:02K-069
PHOSPHORUS  SUPPLYING CAPACITIES OP  PREVIOUSLY HEAVILY FERTILIZED SOILS,
Novais, R., and  Kamprath, E.J.
Universidade Federal de Vicosa, Brazil,  Department of Soils.
Soil Science Society of America Journal, Vol. 42, No. 6, p 931-935, November-
December, 1978.  3 fig, 7 tab, 22 ref.

Descriptors:  Phosphorus, Soil tests, Soil chemical properties, Fertilizers,
Nutrient removal,  Chemical analysis, Soil analysis, North Carolina.

Four Coastal Plain soils and one Piedmont soil heavily fertilized in the past were
intensively cropped in greenhouse pots to determine changes in extractable soil
P  as measured by North Carolina, Bray I and Olsen extractants.  Slopes relating
changes in  extractable P with P removed by cropping were very similar for the
three sandy soils.  Changes in extractable P with the North Carolina and Bray
I extractants were correlated with  P buffer capacity, % clay, and soil surface
area.  The  principal source of P removed by cropping was NH4F-P in sandy Coastal
Plain soils; NH4F-P and NaOH-P supplied equal amounts in the clayey Piedmont
soil.  Sandy Coastal Plain soils which originally contained more than 74 ppm
North Carolina extractable P and 71 ppm Bray I extractable P supplied 82 to 108
kg P/ha to  nine  crops of pearl millet (Pennisetum americanum, cv. Gahi-1).


78:02K-070
CATION EXCHANGE  EQUILIBRIA IN FLORIDA AND INDIANA HISTOSOLS,
Baligar, V.C., Barber, S.A., and Myhre, D.L.
Purdue University, West Lafayette,  Indiana.
Soil Science, Vol. 126, No. 2, p 109-117, August, 1978.  2 fig, 4 tab, 31 ref,
8 egu.

Descriptors:  Cation exchange, Organic soils, Cation adsorption, Selectivity,
Potassium,  Isotherms, Soil chemistry, Soil chemical properties, Florida, Indiana,

Ion exchange equilibria have been investigated in mineral soils, but little infor-
mation is available for organic soils.  This investigation was undertaken to
characterize the cation selectivity' of differing histosols and to determine a
suitable cation  exchange equation to express the ion selectivity in these soils.
Four histosols were incubated for 3 weeks with 5 levels of K and Rb.  At the end
of incubation, ions in soil solution and on the adsorbed phase were determined.
All soils had a  greater fraction of Ca in the exchange phase than in solution,
whereas with Mg,  Mn, K, and Rb, the reverse occurred.  Increasing K and Rb satura-
tion was related to an increase in selectivity coefficient for Rb-K.  On the
Pahokee muck soils, Rb was adsorbed more tightly than K,  where the amount of Rb
added exceeded 1.0 me/100 g of soil.  On the Edwards muck soil, Rb was adsorbed
preferentially to K at all levels.   Magnesium was adsorbed preferentially to Ca
on the Edwards muck soil, but not on the Pahokee soils.  Selectivity coefficients
for K-Ca were calculated using the Kerr, Gapon,  Krishnamoorthy and Overstreet,
Vanselow, and Scheffer and Ulrich equations.   In all but the Scheffer and ulrich
equation, the selectivity coefficient decreased as K and Rb were increased.   In
the latter it increased.  No equation satisfactorily described the system.
                                      107

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 78:02K-071
 NITROGEN AND CHLORIDE LEACHING IN A SANDY FIELD PLOT,
 Cameron, D.R., Kowalenko, C.G., and Ivarson, K.C.
 Soil  Research Institute, Agriculture Canada, Ottawa, Ontario K1A OC6.
 Soil  Science, Vol. 126, No. 3, p 174-180, September, 1978.  3 fig, 2 tab, 15 ref.

 Descriptors:  Nitrogen, Chloride, Leaching, Leachate, Environmental sanitation,
 Denitrification, Nitrates.

 In field experiments conducted on a well-drained, sandy soil, 59 and 99 percent
 of the added chloride was lost by leaching from the 0-75-cm layer by the end
 of October in 1975 and 1976, respectively.  Chloride losses were proportional to
 total precipitation.  The average spring-to-fall rates of N losses for 1975 and
 1976  were 0.65 and 1.45 kg N/ha/day, and were directly proportional to N
 fertilization rates of 120 and 255 kg/ha, respectively.  N03-N and Cl tended to
 show  similar distribution patterns in the profile, and ratios of Cl to N03-N in-
 dicated predominant leaching rather than denitrification losses.  N and Cl losses
 appeared to be associated with irregular, diffuse bulges, rather than with distinct
 peaks of solute moving steadily downward.


 78:02K-072
 INFLUENCE OF PHOSPHORUS ON ZINC, IRON, MANGANESE, AND COPPER UPTAKE BY PLANTS,
 Wallace, A., Mueller, R.T., and Alexander, G.V.
 California University, Los Angeles, Laboratory of Nuclear Medicine and Radiation
 Biology.
 Soil  Science, Vol. 126, No. 6, p 336-341, December, 1978.  3 tab, 28 ref.

 Descriptors:  Nutrient removal, Nutrients, Zinc, Iron, Manganese, Copper,
 Phosphorus, Plant growth, Beans.

 Five  cultivars of soybeans (Glycine max. L.) and a bush bean (Phaseolus vulgaris
 L. cv "Improved Tendergreen")  were grown in nutrient solutions with different
 P levels, solution pH, and, in the case of bush bean, at different Fe levels.
 The objective of the experiments was to obtain more definitive answers to problems
 of P-induced Zn and Fe deficiencies.  Differential solution pH, obtained by
 adding solid phase CaCO3 to the nutrient solution (about pH 7)  vs. a regular
 solution (about pH 4-5), indicates that pH is very important in the effects ob-
 tained.  At high pH, increasing solution P decreased the leaf,  stem, and root
 concentrations of Zn, Mn, and Cu in soybeans.  Iron was decreased in roots, but
 not in leaves and stems.  In contrast, at low pH, increasing the P resulted in
 more  Zn, Mn, and Cu but less Fe in leaves, stems, and roots.  Results with bush
 beans were only slightly different from those with soybeans, and the Zn-P effects
 were  modified slightly by Fe levels.  High P decreased Fe transport to leaves in
 bush  beans at low and high pH, but only at the high Fe level.


 78:02K-073
 EFFECT OF SULFATE IONS ON THE STABILITY AND EXCHANGE CHARACTERISTICS OF AN
 ALUMINUM-INTERLAYERED WYOMING BENTONITE,
 Singh, S.S., and Miles, N.M.
 Soil  Research Institute, Research Branch, Agriculture Canada, Ottawa, Ontario
 K1A 06C, Canada.
 Soil  Science, Vol. 126, No. 6, p 323-329, December, 1978.  2 fig, 4 tab, 16 ref.

 Descriptors:  Bentonite, Suspension, Clay minerals, Sulfates, Chemical precipi-
 tation, X-ray diffraction, Chemical properties, Soil chemistry.

 Alurainura-interlayered, Wyoming bentonite suspensions, containing different
 amounts of precipitated Al, were equilibrated with S04 solutions at different
 concentrations.   The amount of Al precipitated as Al-hydroxy complex was 400,
 550,  and 750 me/100 g clay, and the concentration of SO4 in solution as 10, 20,
 and 30 me/1.  On equilibration, the hydroxy-Al interlayer precipitate in the
Wyoming bentonite reacted with S04 ions, and a neutral precipitate of aluminum
 hydroxy sulfate was formed. Heating the Wyoming bentonite to 700°C resulted in
 complete collapse, showing that the precipitate was no longer present in the
 interlayer space.  A crystalline compound of aluminum liydroxy sulfate was formed
 as evidenced by x-ray diffraction patterns.   In the case of Al-interlayered,
Wyoming bentonite suspensions  that were not equilibrated with SO4 solution, the
 Al-hydroxy precipitate remained in the interlayer space and blocked the exchange
 sites.  Treatment of these samples with S04 solutions resulted in an increase of
 exchange capacity that was concentration-dependent.
                                    108

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 78:02K-074
 EVALUATION OF AMMONIUM  RELEASE BY ALKALINE PERMANGANATE EXTRACTION AS AN INDEX
 OF SOIL NITROGEN AVAILABILITY,
 Stanford, G.
 United States Department of Agriculture, Science and Education Administration,
 Northeastern Region, Biological and Waste Management and Soil Nitrogen Laboratory,
 Beltsville, Maryland  20705.
 Soil Science, Vol.  126, No. 4, p 244-253, October, 1978.  1 fig, 4 tab, 27 ref.

 Descriptors:  Nitrogen, Chemical analysis, Soil chemistry, Organic matter.
 Laboratory tests, Hydrolysis, Oxidation.

 The relation of potentially mineralizable soil nitrogen, NO, to hydrolytic and
 oxidative release of NH4-N from soil organic matter by extraction with alkaline
 permanganate was investigated using 62 soils representing several major agricultural
 regions in the United States.  The NH4-N was recovered by steam-distilling 1-g
 samples of soil during  extraction for 4 min with several concentrations of NaOH
 and KMn04 in different  combinations.  The same concentrations of NaOH, without
 KMn04, were used to determine amounts of NH4-N released by hydrolysis (B)  during
 steam distillation.  Oxidative release was estimated as the difference between
 total NH4-N produced during alkaline permanganate extraction (BOx) and that
 derived by NaOH distillation.  With few exceptions, correlations of NO with BOx
 were as good as, or better than, simple correlations of NO with B or (BOx - B).
 Thus, the extra effort  required for separate NaOH and NaOH-KMn04 extractions did
 not appear to be justified.  It was concluded that the alkaline permanganate
 methods thus far reported by various investigators, as well as modifications
 evaluated in this study, offer a less precise and reliable basis for predicting
 NO than does acid permanganate extraction for measuring oxidative release of
 NH4-N.


 78:02K-075
 OXIDATIVE RELEASE OF POTENTIALLY MINERALIZABLE SOIL NITROGEN BY ACID PERMANAGANATE
 EXTRACTION,
 Stanford, G., and Smith, S.J.
 United States Department of Agriculture, Agricultural Research Service,  Biological
Waste Management and Soil Nitrogen Laboratory, Beltsville, Maryland  20705.
 Soil Science, Vol. 126, No. 4, p 210-218, October, 1978.  6 fig, 2 tab,  13 ref.

 Descriptors:  Nitrogen, Chemical analysis, Soil tests, Organic matter,  Soil
 chemistry. Laboratory tests, Oxidation.

 The relation of potentially mineralizable soil nitrogen, NO, to the oxidative release
of NH4-N from soil organic matter during extraction with acid KMn04 was  investigated,
using 62 soils.   Included in the study were members of 8 soil orders comprising
 43 noncalcareous and 19 calcareous soils.  Soils were extracted with 1 N H2S04 solu-
 tions of 0.05 and 0.1N KMn04 (HOx)  and with 1 N H2S04 (H)  alone for 1 h  at room
 temperature, and amounts of NH4-N released were determined.   The expression HOx -
H denotes the quantity of NH4-N released owning to partial oxidation of  soil organic
matter.   Later,  a more direct and simpler procedure for determining oxidative
NH4-N release was adopted,  in which soils were preextracted with 1 N acid,  and the
soil residues were extracted with acidic KMn04.  Regression equations that may be
useful in predicting NO from the oxidative release of NH4-N were developed.  Amounts
of NH4-N released by oxidation with 1 N H2SO4 solutions of 0.05 and 1.0  N  KMn04,
respectively, were approximately one-third and one-half of NO.   It was concluded
that the NH4-N was derived from oxidation of the soil organic N fraction most readily
susceptible to biological mineralization.
                                     109

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                                   SECTION XII


                 WATER SUPPLY AUGMENTATION AND CONSERVATION

                     WATER YIELD IMPROVEMENT  (GROUP 03B)


78:03B-001
ANALYSIS OF FALLOW-FARMING SYSTEMS IN SEMI-ARID AFRICA USING A MODEL TO SIMULATE
THE HYDROLOGIC BUDGET,
Hall, A.E., and Dancette, C.
California University, Riverside, Department of Plant Sciences.
Agronomy Journal, Vol. 70, No. 5, p 816-823, September-October, 1978.  10 fig,
4 tab, 16 ref, 7 equ.

Descriptors:  Semiarid climates. Fallowing, Model studies, Simulation analysis,
Hydrologic budget, Evaporation, Water conservation, Soil moisture, Root system.

A model was developed to predict bare soil evaporation, crop water use, and the
distribution of water in the soil.  Comparisons with hydrologic budget data ob-
tained in the field with bare soil, cowpeas (Vigna unguiculata (L.) Walp.), and
millet (Pennisetum typhoides  (Burm. f.) S. and W.) indicated that the models
performed adequately for the conditions and objectives of the study.  Simulations
of annual fallow, predicted that the amounts of water conserved in the soil would
rapidly decrease with decreases in annual rainfall.  The simulations predicted
that substantial quantities of water may be conserved in the soil by partial
fallow during wetter years.  More soil moisture would be conserved with the
shorter cycle variety, but the longer cycle variety would have greater need for
this moisture in this climatic zone during dry years, indicating a possible
advantage of rotations involving short cycle,  and long cycle crops.  The simula-
tions predicted that present varieties may only use a small proportion of the
moisture that may be stored below 150 cm depth in the soil by partial fallow,
indicating a possible need for developing varieties with faster growing, deeper,
root systems.
                                     110

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                                 SECTION XIII

                  WATER SUPPLY AUGMENTATION AND CONSERVATION

                 USE OF WATER OF IMPAIRED QUALITY (GROUP 03C)


 78:03C-001
 TESTING SALT TOLERANCE VARIABILITY AMONG TALL WHEATGRASS LINES,
 Shannon, M.C.
 United States Salinity Laboratory, United States Department of Agriculture,
 4500 Glenwood Drive,  Riverside, California  92501.
 Agronomy Journal,  Vol. 70,  No.  5,  p 719-722,  September-October,  1978.   1 fig,
 3 tab, 22 ref.

 Descriptors: Wheatgrass,  Salt tolerance,  Varieties,  Variability,  Plant
 breeding, Plant physiology.

 In the present  study  a screening procedure was evaluated to determine  its
 usefulness in detecting variation  among introductions of tall wheatgrass (Agro-
 pyron elongatum (Host) Beauv.). In greenhouse sand flats,  32 lines  of tall
 wheatgrass were established and subjected to  stepwise increases  in salinity  up
 to 765 meq/liter or until  severe leaf  damage  resulted.   The lines  were classified
 into five groups based on  relative leaf damage and recovery rates  from salt
 treatment.  Repeating the  screening procedure on seven each of the most tolerant
 and most sensitive lines reaffirmed the results of the first screening.   Mineral
 analyses indicated that tolerance  was  associated with restricted accumulation
 of Na,  Ca, and  Cl  in  the shoots.   Proline  and soluble sugars  contributed to
 osmotic adjustment at high  salinities,  but sensitive  and tolerant  lines did  not
 differ in proline  content.   This screening technique  appeared to discriminate
 between lines with different ion transport properties and different  salt
 tolerances.   The sensitive  and  tolerant lines identified may  be  beneficial in
 future breeding and physiological  studies.


 78:03C-002
 ROOT GROWTH ALONG  PLEXIGLAS  SURFACES BY SUGARCANE UNDER DIFFERENT  SOIL SALINITY
 CONDITIONS,
 Gerard,  C.J.
 Texas ASM University,  Vernon,  Texas Agricultural Experiment Station.
 Agronomy Journal,  Vol.  70, No.  4,  p 639-643,  July-August, 1978.  7 fig,  1 tab,
 12 ref.

 Descriptors:  Root development,  Salinity, Moisture stress,  Growth  stages, Sugar-
 cane,  Plant growth, Saline soils,  Crop  response,  Saline water.

 Root growth of  sugarcane (Saccharum officinarum L.)  in  soils  irrigated with
waters  with electrical conductivities of 1.1,  5.0, and  8.0 mmhos/cm varied with
 stage of plant  growth,  time  and salinity treatments.  Root growth was greatest
 at soil depths  of  20  to  60 cm in May, June, and  July,  a period of high growth
 rate and high evaporative conditions.   During  these months, average root inten-
 sities  of  sugarcane,  irrigated with waters with  salinities of  1.1, 5.0, and  8.0
mmhos/cm,  were  about  0.5, 1.0,  and  1.5  mm/sq  cm,  respectively.  Moisture stress
 induced by osmotic  potentials of about  -1.8 and  -2.9 bar  and high evaporative
 conditions  stimulated  root intensities  but reduced top growth by 22 and 50%,
 respectively.   These  studies using root chambers  have contributed to a better
understanding of the  interactive influences of stages  of plant growth, salinity,
and  environment on  root  growth by sugarcane.


 78:03C-003
THE  EFFECT OF SALT  PRECIPITATION AND HIGH SODIUM CONCENTRATIONS ON SOIL HYDRAULIC
CONDUCTIVITY AND WATER RETENTION,
Frenkel, H., Hadas, A.,  and Jury, W.A.
California University, Riverside, Department of Soil and Environmental Sciences.
Water Resources Research, Vol.  14,  No.  2, p 217-222,  April, 1978.  5 fig, 4 tab,
21 ref,  8  equ.


                                      Ill

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 Descriptors:   Saline water, Water  quality,  Salinity,  Irrigation,  Leaching,  Crop
 response,  Pollution abatement,  Chemical  precipitation,  Hydraulic  conductivity,
 Soil-water-plant relationships.

 Controlled irrigation management of  moderate  to poor  quality water must assure
 sufficient movement of solution through  the root  zone to maintain a  salinity
 regime which  a crop can tolerate while at the same  time minimizing the deteriora-
 tion  of groundwater or river  quality.  The  work reported here analyzes the  major
 plant-soil-salinity interactions resulting  from irrigation with saline water at
 controlled leaching fractions.   Simulations are run for leaching  fractions  of
 0.30,  0.05, and 0.01 and three  different water uptake patterns for two high-sul-
 fate  waters with different salinity  levels:   2.1  and  6.6 mmho/cm.  Results
 suggest that  soil hydraulic conductivity and  water  retention should  not be  ad-
 versely affected by high sodium levels or cumulative  salt precipitation even at
 very  low leaching fractions.  However, it is  probable that plant  activity will
 be  impaired by the  lower leaching  fractions because of  high osmotic  pressure
 within the root zone and that root proliferation  could  be reduced by soil struc-
 ture  cementation resulting from salt precipitation.


 78:030-004
 GRAPEFRUIT RESPONSE TO VARIABLE  SALINITY IN IRRIGATION  WATER AND  SOIL,
 Bielorai,  H.,  Shalhevet,  J.,  and Levy, Y.
 Institute  of  Soils  and Water, Agricultural  Research Organization, The Volcani
 Center,  Bet Dagan,  Israel, Division  of Environmental  Physiology and  Irrigation.
 Irrigation Science,  Vol.  1, No,  1, August,  1978,  p  61-70.  3 fig, 4  tab, 16 ref.

 Descriptors:   Saline water, Irrigation water.  Salinity, Crop response, Grapefruit,
 Osmotic  pressure, Salts,  Leaching, Saline soils.

 Results  were  reported from a  long-term field  experiment designed  to  determine the
 effect of  irrigation water salinity  on the yield  and  water uptake of mature grape-
 fruit  trees.   Treatments  were started in 1970  and consisted of chloride concen-
 trations in the irrigation water of  7.1, 11.4  and 17.1  meq/1 added as NaCl +
 CaC12  at a 1:1  weight ratio.  For  the last  four years of the experiment, 1973 to
 1976,  yield was linearly  related to  the  mean  chloride concentration  in the soil
 saturation extract  weighted according to the distribution of water uptake with
 depth  and  time.   There was a 1.45% yield  reduction for each 1 meq/1 increase in
 chloride concentration above a threshold value of 4.5 meq/1.  This corresponded
 to  a  13.5% decrease per 1 mmho/cm increase  in  the electrical conductivity of the
 soil saturation extract above a  threshold value of  1.2  mmho/cm.  Total water up-
 take was reduced as salt  concentration in the  soil  increased.  Salt  accumulation
 in  the  soil depended on the quantity and salt  concentration of the irrigation
 water,  rainfall,  and on the amount of leaching.  No leaf symptoms of either Cl(-)
 or  Na(+) injury were observed.   The  results indicate  an osmotic—rather than a
 specific ion effect—of salinity on  grapefruit yield.


 78:030-005
 SALT TOLERANCE  IN THE WILD RELATIVES OF  THE CULTIVATED  TOMATO:  RESPONSES OF
 SOLANUM  PENNELLII TO HIGH SALINITY,
 Dehan, K.,  and  Tal,  M.
 Ben Gurion University  of  the Negev, Beer Sheva, Israel, Department of Biology,
 Irrigation Science,  Vol.  1, No.   1,  August, 1978, p  71-76.   5 tab, 12 ref.

 Descriptors:  Salt  tolerance, Salinity, Tomatoes,  Moisture deficit,  Ions,.
 Saline soils.

 The cultivated  tomato Lycopersicon esculentum/ cultivar Rheinlands Ruhm,  and the
wild species Solanum pennellii accession Atico, were compared with respect to
 their salt tolerance.   The wild  species was found to be more salt tolerant than
 the cultivated  tomato.  In contrast  to L. esculentum plants, the growth of the
wild species was not impaired by the high salinity,  although the latter accumulated
more C1C-3  and Na(-i-)  ions and its K+ level decreased under salinity.   The smaller
 increase in water deficit under salinity in the wild species was attributed to
 its higher accumulation of ions.
                                    112

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78:030006
DRAINAGE PRACTICE IN IMPERIAL VALLEY,
Hermsmeier, L.F.
Imperial Valley Conservation Research Center, United States Department of
Agriculture-Agricultural Research Service, Brawley, California.
Transactions of the American Society of Agricultural Engineers, Special Edition,
Vol. 21SW, No. 1, p 105-109, February 20, 1978.  1 fig, 7 tab, 10 ref.

Descriptors:  Salinity, Drainage practices, Drainage, Drainage programs, Colorado
River Basin, Saline water, Water quality. Salt balance, Colorado River,
California.

The Imperial Valley in California has been irrigated by Colorado river water from
the start of the century.  The irrigation water quality was recognized as
presenting possible drainage and salinity problems.  As early as in 1902, irriga-
tion engineers of the United States Department of Agriculture indicated that
the water table and salinity of the valley needed to be controlled.  Even to
this day, the salinity remains to be a problem in the Imperial Valley.  The
purpose of this paper was to describe briefly all the drainage studies and develop-
ments that have taken place until the recent years.  It also reports the soil
types, climate, drainage cost and the crops grown in the valley.
                                     113

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                                 SECTION XIV


                 WATER SUPPLY AUGMENTATION AND CONSERVATION

           CONSERVATION IN'DOMESTIC AND MUNICIPAL USE (GROUP 03D)


78:030-001
ESTIMATION OF URBAN IRRIGATION WATER USE AND REQUIREMENT,
Fok, Y-S., and Murabayashi, E.T.
Hawaii University, Honolulu, Department of Civil Engineering.
Paper No. 78-2030, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 7 p.  7 ref,.l equ.

Descriptors:  Water conservation. Irrigation water. Landscaping, Consumptive use,
Water requirements, Aesthetics, Water utilization, Vegetation, Estimating,
Methodology.

The difference between normal urban irrigation water use and the consumptive use
requirement is the potential amount of water that might be saved without ad-
verse economic consequences to urban property values.  These savings fit the
general demand on better urban water use efficiency and/or urban water conserva-
tion.  Methods for the estimation of urban irrigation water use and requirement
are presented in this paper.
                                    114

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                                   SECTION XV

                    WATER SUPPLY AUGMENTATION AND CONSERVATION

                      CONSERVATION  IN AGRICULTURE  (GROUP  03F)


 78:03F-001
 MANAGEMENT OF  IRRIGATED  SOYBEANS ON A MODERATELY COARSE-TEXTURED SOIL IN THE UPPER
 MIDWEST,
 Cassel,  O.K.,  Bauer,  A.,  and Whited, D.A.
 North  Carolina State  University, Charlotte, Department of Soil Science.
 Agronomy Journal, Vol. 70, No. 1,  p 100-104, January-February, 1978.  2 fig, 4
 tab, 22  ref.

 Descriptors:   Soybeans,  Supplemental irrigation, Water management  (applied), Fer-
tilization,  Nitrogen,  Nitrates, Tensiometers,  Leaching,  Irrigation programs.

 The objectives of this study were  to determine the yield potential of supplementally
 irrigated soybeans  on moderately coarse-textured soils and to develop an irrigation
 schedule  for efficient water management.  The study, conducted on Maddock sandy
 loam from 1972 to 1974,  employed a split-split plot design with water level as the
 main block and N fertility rates (0, 56, 112, and 224 kg/ha) as subplots.  Water
 levels were Wl (dryland), W2  (underirrigation), W3 (optimum) and W4  (overirrigation).
 Sub-subplotS were planting dates in 1972 and cultivars in 1973 and 1974.  Grain
 yields were significantly different for water levels during each of the three years.
 Three-year yield means were 543, 1,823, 2,428,'and 2,164 kg/ha for Wl, W2, W3,
 and W4,  respectively.  The application of 224 kg/ha N fertilizer in 1972 increased
 grain yield at the  0.95  probability level.  An irrigation scheduling based upon
 tensiometers proved effective  in applying irrigation water.  Based upon results
 of this  study,  it was concluded that soybeans can be seriously considered as a
 crop to be included in cropping systems for irrigated, moderately coarse-textured
 soils in  the Upper  Midwest.


 78:03F-002
 EFFECTS OF CULTURAL PRACTICES  ON GRAIN YIELD OF IRRIGATED WHEAT,
 Day, A.D., Jackson, E.B., and  Alemu, A.
 Arizona University, Tucson, Department of Plant Sciences.
Agronomy  Journal, Vol. 70, No..2, p 279-282, March-April, 1978.  4 tab, 21 ref.

 Descriptors:   Wheat,  Cultural  control, Nitrogen, Fertilization, Crop production,
 Planting  management, Beds, Irrigation.

 Experiments were conducted at  Yuma, Arizona, to study the effects of N fertilizer
 treatments in  combination with methods of planting and row positions on beds, on
 the yield and  quality of wheat grain.  Six N fertilizer treatments (34, 17 + 17,
 68, 34 +  34, 136, and 68 + 68  kg/ha), two methods of planting (on the flat and on
 beds) , and four row positions  on beds (north, south,  east, and west)  were evaluated.
 Flat plantings resulted  in higher wheat grain yields than did bed plantings;
however,  bed plantings produced higher grain volume-weights. -Within planting
methods,  N fertilizer treatments did not significantly influence grain yields or
 grain volume-weights.  Grain yield components were similar for both planting
methods.  Wheat grown on beds with an east-west orientation produced more heads
per unit  area, more seeds per  head, and higher grain yields than did wheat pro-
duced on  beds  oriented in a north-south direction.  Wheat responded to N fertili-
 zation when grown on both flat and bed plantings during the winter months in the
Southwest.


 78:03F-003
EFFECT OF FERTILIZATION ON PENNCROSS CREEPING BENTGRASS,
Waddington,  D.V., Turner, T.R., Duich, J.M., and Moberg, E.L.
Pennsylvania State  university, University Park, Department of Agronomy.
Agronomy  Journal, Vol. 70, No. 5, p 713-718, September-October, 1978.  2 fig, 7
tab, 15 ref.
                                    115

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 Descriptors:  Fertilization, Turf grasses, Fertility, Productivity, Nitrogen,
 Phosphorus, Potassium, Soil tests.

 A field study was conducted on fine, mixed soil to determine the effects of N
 sources (agrinite, Milorganite, ureaform, and urea), P rates (0, 0.49, 0.98, and
 1.95 kg/100 m2), and K rates (0, 0.76, and 1.52 kg/100 m2) on soil nutrient levels
 and the growth, quality, and chemical composition of "Penncross" creeping bentgrass
 (Agrostis palustris Huds.) maintained as putting green turf.  Wilting, disease,
 chlorosis, and annual bluegrass (Poa annua L.)  infestation were used to assess
 quality.  Fertilization with Milorganite increased available soil P and Mg.
 Application of K increased both tissue and available soil K.  However, a greater
 increase in soil K and a smaller increase in tissue K were obtained by the second
 additional increment of K than the first one.  The greatest change in tissue P
 occurred with the first incremental addition of P.  Tissue P was not greatly
 affected by soil P above 224 ppm.   Less severe  summer wilting was observed with
 Agrinite,  Milorganite, and K treatments.  Annual bluegrass invasion was favored
 by P and K fertilization and the effect of one  was enhanced by the other.  Mil-
 organite,  which increased soil P,  also favored  annual bluegrass.


 78:03F-004
 EFFECTIVENESS OF NITRAPYRIN IN CONTROLLING NITRIFICATION OF FALL AND SPRING-
 APPLIED ANHYDROUS AMMONIA,
 Hendrickson,  L.L.,  Walsh, L.M.,  and Keeney,  D.R.
 Wisconsin University,  Madison,  Department of Soil  Science.
 Agronomy Journal,  Vol.  70, No.  5,  p 704-708,  September-October,  .1978.   4 tab,  18
 ref.

 Descriptors:   Nitrification,  Inhibitors,  Denitrification,  Nitrogen,  Ammonia,  Crop
 response,  Fertilizers,  Corn (field).

 Fertilizer N  applied in the fall for  the next growing season is  often  less
 efficient  than N applied closer  to  the time of  plant use.   Efficiency  might be
 greatly improved by  maintaining  the N as NH4, through the  use of the nitrification
 inhibitor,  Nitrapyrin  t2-chloro-6  (trichloromethyl)  pyridine].   To evaluate this
 hypothesis, field  trials were established during 1975 to 1977 in south central
 Wisconsin  using 84  to  168 kg/ha N applied as  anhydrous ammonia with  and without
 0.55 kg/ha Nitrapyrin.   The results indicated that while nitrification can  be
 significantly  slowed by  application of nitrapyrin, a yield response  does  not
 result.  It was  thought  that a response might have been  obtained had a crop been
 grown on the poorly-drained area adjacent to  the harvested area  since  appreciable
 N appeared to  have been  denitrified at this site.  Nitrification inhibition by
 nitrapyrin varied widely within the same  field.  The results  illustrated  the
 problems involved  in predicting whether nitrapyrin application will  be effective
 in reducing nitrogen losses and increasing yields,


 78:03F-005
 EVALUATION  OF  NITRAPYRIN AS A MEANS OF IMPROVING N EFFICIENCY IN IRRIGATED  SANDS,
 Hendrickson, L.L., Keeney,  D.R., Walsh, L.M., and Liegel,  E.A.
 Wisconsin University, Madison, Department of Soil Science.
 Agronomy Journal, Vol. 70,  No. 5, p 699-703, September-October,  1978.   3  fig, 5
 tab, 24  ref.

 Descriptors:  Nitrification, Inhibitors,  Nitrogen, Ammonia, Nitrates, Fertilizers,
 Potatoes, Leaching, Osmotic pressure.

 The objective of this research was to  determine  if optimum levels of N might be
 maintained throughout the growing season  by delaying nitrification with a nitri-
 fication inhibitor, Nitrapyrin.  Several  field experiments were  conducted oh a
 Plainfield loamy sand involving various N sources,  rates,  and times of application
with and without Nitrapyrin.  Potato tuber yield and the forms and distribution
of N in and below the fertilizer bands were determined.  Nitrapyrin extended the
persistence of applied NH4  in all experiments, but inhibition of nitrification wasof
relatively short duration.  Nitrapyrin persistence was likely reduced by the more
rapid volatilization and hydrolysis in sandy soils.  Further, the effectiveness
of Nitrapyrin was likely limited by rapid leaching NH4 out of the Nitrapyrin-
 treated zone.   Application of Nitrapyrin reduced both total tuber yield and the
proportion of marketable tubers.  The soil sampling data showed that Nitrapyrin
maintained a much higher NH4-N/NO3-N ratio than comparable nonnitrapyrin treatments-

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It appears that the predominance of NH4-N interfered with plant metabolism so
that both yield and normal development of tubers were impaired.


78:03F-006
ZINC NUTRITION OF RICE AS INFLUENCED BY RATES OF GYPSUM AND ZN FERTILIZATION OF
ALKALI SOILS,
Takkar, P.N., and Singh, T.
Punjab Agriculture University, Ludhiana, Department of Soils.
Agronomy Journal, Vol. 70, No. 3, p 447-450, May-June, 1978.  2 fig, 2 tab, 15
ref, 2 egu.

Descriptors:  Rice, Nutrient requirements, Zinc, Gypsum, Alkaline soils, Crop
response, Fertilization, Reclamation, Submerged plants.

Three field experiments were conducted on Zn deficient alkali soils, two on
Natraquic calciorthids, and one on Aquic Camborthids, to determine the effect of
gypsum and Zn fertilization alone and in combination on the Zn nutrition of rice
IR 8.  Three rates of gypsum and three rates of Zn and their possible combinations
were tried.  At all the three locations, the growth of the rice crop was very
poor and exhibited Zn deficiency symptoms in control plots.  The yield and Zn
uptake was higher in alkali soil high in CaCO3 and low in pH than in soils low
in CaCO3 and high in pH.  Gypsum application markedly decreased the available
Zn from deficient to adequate levels.  Optimum response of rice to Zn was ob-
served at 11.2 kg Zn/ha except in one of.the Nitraquic calciorthids where it was
22.4 kg Zn/ha.  The beneficial effect of Zn application to rice grown on the
alkali soils under investigation was far more than that of gypsum.


78:03F-007
RADIATION AND ENERGY BALANCE OF SPRINKLER AND TRICKLE IRRIGATED FIELDS,
Ben-Asher, J., Fuchs, M., and Goldberg, D.
Ben-Gurion University, Beer Sheva, Israel, Institute of Soil and Water.
Agronomy Journal, Vol. 70, No. 3, p 415-417, May-June, 1978.  1 fig, 2 tab, 13
ref, 8 equ.

Descriptors:  Water conservation, Sprinkler irrigation, Tomato, Evaporation,
Energy budget, Evapotranspiration, Radiation, Albedo.

Water conservation claims in favor of trickle irrigation are poorly documented.
The radiation and energy balance of tomatoes grown on sand dune soil and on bare
soil irrigated by sprinkling and trickling were compared.  Under trickle irrigation,
the average ratio of five energy balance measurements of evapotranspiration over
evaporation pan (Class A)  was 0.3, compared with 0.60 obtained under sprinkler
irrigation.  The comparison of radiation balance over the trickle and sprinkler
irrigated plots indicates that the increased radiant heat loss and albedo from the
dry portion of the trickle irrigated plot decreases the available evaporative
energy at ground level.   The smaller radiant heat load combines with the resis-
tance of the dry soil to water flux to reduce the evaporation of the trickle
irrigated plot.


78:03F-008
INFLUENCE OF WATER AND FERTILIZER MANAGEMENT ON YIELD AND WATER-INPUT EFFICIENCY
OF CORN,
Rhoads, F.M., Manse11, R.S., and Hammond, L.C.
Florida University, Quincy, Department of Soil Sciences.
Agronomy Journal, Vol. 70, No. 2, p 305-308, March-April, 1978.  2 fig, 4 tab, 9 ref.

Descriptors:  Corn (field), Water management (applied), Fertilizers, Nutrients,
Irrigation, Leaching, Soil-water-plant relationships.

This study was conducted to evaluate efficiency of water input in terms of corn
grain yield per unit of water, with two fertilizer application methods under three
soil-water management systems on a Troup loamy sand.  Water management consisted
of (a)  control—natural rainfall only, (b)  trickle irrigation scheduled daily
(0.64 cm/day), and (c) trickle irrigation scheduled by tensiometer (1.30 cm/
application).  Tensiometers were placed in each treatment at six depths between
15 and 150 cm below the soil surface and rea'dings were recorded daily.  Methods



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 of applying fertilizers were designated (a)  conventional—1/3 of N and all P and
 K applied broadcast preplant, and remainder of N applied in two sidedressings;
 (b)  program fertilization—N-P-K applied broadcast in small increments (5, 5,  10,
 20,  20, 20,  and 20%)  at two-week intervals after corn emerged.   Average grain
 yields for the above water management treatments were 2,790,  4,160,  and 5,700  kg/
 ha respectively.   Highest irrigation water-input efficiency (150  kg/ha/cm)
 occurred with program fertilization and tensiometer scheduled irrigation.   Irri-
 gation water-input efficiency was lowest (10 kg/ha/cm)  with corn receiving daily
 irrigation and conventional fertilization.


 78:03F-009
 ECONOMIC ANALYSIS OF IRRIGATION PRODUCTION FUNCTIONS:  AN APPLICATION OF LINEAR
 PROGRAMMING,
 Pomareda,  C.
 International Bank for Reconstruction and Development,  Washington,  D.C., Develop-
 ment Research Center.
 Water Resources Bulletin,  Vol.  14,  No.  1,  p 24-34,  February,  1978.   1 fig, 4 tab,
 9  ref.

 Descriptors:   *Economic analysis,  *Irrigated agriculture,  "Linear programming,
 *Water utilization,  *Production function,  Optimization,  Resource allocation,
 Profit,  Crops,  Mathematical models.

 For  estimating the yield response to irrigation water,  good and varied information
 is available;  however,  little and only  partial (for individual  crops)  economic
 analysis has  been made  of  this  information.   Herein,  the economic analysis of
 irrigation production  functions is  discussed and a  modified separable linear
 programming model is used  for examining optimal levels  of  water use when,  at the
 farm level, various  crops  with different water response functions compete  for the
 same scarce resource.   The effects  of alternative water availabilities on  the
 optimal  levels  of water use are explored using a multicrop farm model in which,
 in principle,  the full  water response function for  each crop  can be included.   The
 farm objective  function is specified as the  maximization of profits from various
 crops,  given  a  restriction in the  availability of water and other inputs.  This
 method  provides advantage  over  the  partial one-crop type of analyses  because it
 captures intercrop, tradeoffs in water and  land use  in response  to economic policies
 or changes in water  supply.


 78:03F-010
 NITROGEN BALANCES FOR THE  SANTA MARIA VALLEY,
 Lund, L.J., Ryden, J.C., Miller,  R.J.,  Laag,  A.E.,  and Bendixen,  W.E.
 California University,  Riverside,  Department of Soil  and Environmental Sciences.
 Proceedings of  National Conference on Management of Nitrogen  in  Irrigated  Agri-
 culture, California University,  Sacramento,  California,  p  395-413, May 15-18,
 1978.   6 tab, 7 ref.

 Descriptors:  Nitrogen,  Nutrient removal,  Denitrificatiqn,  Vegetable  crops,
 Leaching.

 A  simplified steady-state  model  has  been used to  develop nitrogen balances in the
 Santa Maria Valley, California.  Balances  have  been developed for selected manage-
 ment units and  for the  valley as a whole.  The  balance developed  for  a  field
 cropped  with vegetables  for  the  past twelve  years showed that 30% of  the applied
 nitrogen was removed in harvested crop,  37% was  leached  below the root  zone and
 33%  was  unaccounted-for, which was attributed to  gaseous losses of nitrogen as
 products of denitrification.  Direct  field measurement of denitrification over an
 eight-month period at one  site  in the same field  found a 29% loss of  the applied
 nitrogen.  The  first estimation of the  nitrogen balance  in  the valley  attributed
 24%  of the applied nitrogen  to removal  in harvested crops,  39% to leaching and 37%
 to denitrification.


 78:03F-011
 ECONOMIC CONCEPTS AND POLICIES RELATED  TO CONTROLLING NONPOINT SOURCE POLLUTION
 STEMMING FROM AGRICULTURE,
Whittlesey, N.K.,  and Barkely, P.W.
Washington State  University, Pullman, Department of Agricultural Economics.
 Proceedings of  National Conference on Management of Nitrogen in Irrigated

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 Agriculture,  California University,  Sacramento,  California,  p 333-353,  May 15-18,
 1978.   14 ref.

 Descriptor:   Pollution abatement.

 This paper describes the role of economics in solving nonpoint source pollution
 problems in terms that are understandable for the  noneconomist.   An economist
 attempts to watch over the process of converting natural  resources  into marketable
 commodities  to  assure that the process achieves  the greatest possible good for
 members of society.   Economic tools  are well  equipped to  handle  this process for
 goods  and resources  known as  private property, those items used  exclusively by  the
 individual owners.   Unfortunately, most pollution  problems occur through the use
 and misuse of public property,  those items owned and used jointly by all members
 of society.   Air and water are the most common examples of public property.  The
 paper  describes economic concepts and public  policies that are useful for inter-
 nalizing the  costs caused by  pollution and abating or solving pollution caused
 problems.   The  concepts of opportunity cost and  income distribution and their
 role in pollution abatement are discussed.  Methods of choosing  levels  of abate-
 ment include  the extremes of  zero pollution and  that which can be achieved by
 best management practices. The economic and  social optimum  probably lies between
 these  extremes.   Arbitrary standards are sometimes imposed as a  compromise between
 the extremes  of zero pollution and no abatement  in an effort to  approximate optimal
 levels of  abatement.


 78:03F-012
 DIAGNOSTIC TECHNIQUES  USED TO IDENTIFY OPTIMUM LEVELS OF  NITROGEN FERTILIZATION
 FOR IRRIGATED CROPS,
 Jackson,  T.L.
 Oregon State  University,  Corvallis,  Department 'of  Soil Science.
 Proceedings of  National Conference on Management of Nitrogen in  Irrigated
 Agriculture,  California University,  Sacramento,  California,  p 321-332,  May  15-18,
 1978.   27  ref.

 Descriptors:  Nitrogen,  Fertilization,  Irrigation  water,  Nitrates.

 The nitrogen  available for plant growth comes primarily from 1)  the  nitrogen
 released  from soil humus  and  crop residues, 2) nitrogen added as  commercial ferti-
 lizers  and 3) residual inorganic nitrogen  from previous growing  seasons  or pre-
 vious  crops.  Irrigation  ensures adequate moisture and relatively uniform yields
 from year  to  year.   Irrigation  also  makes  feasible the application of fertilizer
 nitrogen during  the  growth of  the crop and  this  provides  the  opportunity to use
 soil and plant  analysis early  in the crop  season to assess nitrogen  needs.
 Examples of the  use  of diagnostic techniques  for estimating  the  fertilizer nitro-
 gen required  to  supplement residual  nitrogen  levels  and the  capacity of  the soil
 to  release nitrogen  are presented.


 78:03F-013
 USE OF MATHEMATICAL  RELATIONSHIPS TO  DESCRIBE THE  BEHAVIOR OF NITROGEN  IN THE
 CROP ROOT  ZONE,
 Davidson,  J.M.,  and  Rao,  P.S.C.
 Florida University, Gainesville, Department of Soil Science.
 Proceedings of National Conference on  Management of Nitrogen  in Irrigated
 Agriculture, California University,  Sacramento, California,  p 291-319,  May 15-18,
 1978.   7 fig, 3  tab, 27 ref,  7  equ.

 Descriptors:  Nitrogen, Denitrification, Root 2one, Soil water movement, Mathemati-
 cal  studies.

 A procedure to estimate the movement of water-soluble  nitrogen species  (N03 and
 NH4) was developed by  assuming  that  (i) the soil-water residing in all pore-
 sequences participates  in  the transport process,  and that (ii) the soil-water
 initially present in the soil profile was completely displaced ahead of the
water entering at the  soil surface.   Field-capacity and initial soil-water con-
 tent distribution in addition to total water inputs were necessary parameters to
 estimate solute transport  in the root  zone.  First-order kinetics were assumed  to
describe the nitrogen transformations  (mineralization, immobilization,  nitrifica-
 tion, and denitrification).  These transformation processes were considered to
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 occur under  ideal  conditions.   Plant  uptake of water and nitrogen  (nitrate
 and ammonium) was  estimated, respectively, from potential evapotranspiration and
 nitrogen uptake  rate  under  ideal  environmental conditions for a given crop.  Actual
 plant uptake of  water and nitrogen was  dependent upon  the available soil water
 and total mineral  nitrogen  within the crop root zone.  These mathematical rela-
 tionships could  be solved using a programmable desk-top calculator; however, a
 larger computer  was needed  when more  complex submodels were employed to describe
 soil-water uptake.  The proposed  mathematical relationships can provide field
 managers  and regulatory personnel with  an integrated description of the behavior
 of  nitrogen  in  the root zone during a crop growing  season.


 78:03F-014
 MONITORING WATER FOR  NITROGEN LOSSES  FROM CROPLANDS,
 Tanrji,  K.K.
 California University, Davis, Department of Land, Air and Water Resources.
 Proceedings  of National Conference on Management of Nitrogen in Irrigated Agri-
 culture,  California University, Sacramento, California, p 251-263, May 15-18,
 1978.   10 ref.

 Descriptors:  Nitrogen, Return  flow,  Irrigated lands, Monitoring, Water quality.

 This  paper reviews  monitoring for nitrogen in surface and subsurface return flows
 from  irrigated lands.  Presented  are  the elements of a monitoring program:
 objectives of monitoring, parameters  to be measured, sampling programs that in-
 clude site selection,  sampling  frequency and sampling method, laboratory methods
 for nitrogen determinations, requirements for resources and facilities, evaluations
 of  collected data  and other support information and data, and dissemination of
 monitored results.  Each of these elements are appraised and a conclusion is
 drawn on  monitoring waters  for  nitrogen losses from croplands.


 78:03F-015
 EFFECT OF WATER  MANAGEMENT  ON NITRATE LEACHING,
 Letey, J., Biggar,  J.W., Stolzy,  L.H., and Ayers, R.S.
 California University, Riverside, Department of Soil and Environmental Sciences.
 Proceedings  of National Conference on Management o-f Nitrogen in Irrigated Agri-
 culture,  California University, Sacramento, California, p 231-249, May 15-18,
 1978.  4  fig, 3  tab.

 Descriptors:  Nitrates, Leaching, Water pollution, Water management, Nitrogen,
 Fertilization, Effluents,  Correlation analysis.
            *
 Nitrates which are  leached  (transported below the root zone)  represent a resource
 loss  and  a potential  contribution to  water pollution.  The amounts of leached
 nitrates  for a given  time period  were determined at various commercial farming
 sites  in  California and in  a carefully controlled experimental plot receiving
 various water and  fertilizer application treatments.  Some of the agricultural
 sites had  tile drainage systems and others had "free drainage" to the groundwater.
 Linear regression analyses were conducted on the data.  Similar results were
 observed  for the tile  and free drainage systems.   The highest correlation coeffi-
 cient was  for amount  leached versus drainage volume followed by amount leached
 versus fertilizer nitrogen  application.   In most cases there was no significant
 correlation between nitrate concentration in the water below the root zone and
 drainage volume or  fertilizer nitrogen application.  A significant linear relation-
 ship between amount of leached nitrate and drainage volume was also obtained at
 the experimental plot.


 78:03F-016
 LEACHING OF NITRATE FROM SOILS,
 McNeal, B.L., and Pratt, P.P.
Washington State University, Pullman,  Department of Agronomy and Soils.
 Proceedings of National Conference on Management of Nitrogen in Irrigated
 Agriculture, California University,  Sacramento, California,  p 195-230., May 15-18,
 1978.  4  fig, 5 tab,  35 ref.

 Descriptors:  Nitrates, Nitrogen, Leaching,  Irrigated land,  Denitrification,
Waste disposal.
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Calculation of soil solution nitrate concentrations, and of mass emissions of
nitrate, are illustrated.  Estimation of average water flux from nitrate/chloride
ratios, and from drain field outflows, are discussed.  The high potential for
nitrate leaching from irrigated animal and municipal waste disposal sites is
mentioned, with stress being placed on the high denitrification potential at
many such sites, because of high soluble carbon loadings, high soil microbe
levels, and rapid oxygen depletion.  Root zone and subsoil nitrate-nitrogen
values are provided for typical croplands of southern California and central
Washington.  Such values are related to irrigation management and to downward
water flux.  Crop differences in ability to utilize all soluble nitrate from the
soil solution are stressed, and some management alternatives for preventing deep
percolation losses of nitrate are detailed.  Predictions of nitrate leaching losses
from data for nitrogen application rate and drainage water volume are discussed.
Typical predictions are presented and are compared to experimentally-measured
values.  Overpredictiori of nitrate leaching estimates for some furrow-irrigated
tracts in the Pacific Northwest is demonstrated.


78:03F-017
VOLATILE LOSSES OF NITROGEN FROM SOIL,
Rolston, U.E.
California University, Davis, Department of Land, Air and Water Resources.
Proceedings of National Conference on Management of Nitrogen in Irrigated
Agriculture, California University, Sacramento, California, p 169-193, May 15-18,
1978.  4 fig, 18 ref.

Descriptors:  Denitrification, Volatility, Nitrogen, Fertilization.

Nitrogen may be lost from soil inlhe gaseous form by two major mechanisms, ammonia
volatilization and denitrification.  Ammonia gas may be lost to the atmosphere
whenever ammonium compounds are applied to the soil surface.  The greatest ammonia
losses occur from calcareous soils at high soil pH.  Fertilizers such as urea and
ammonium sulfate result in greater ammonia loss than that from ammonium nitrate
when applied to a moist soil surface.  More than 50% of the applied fertilizer may
be lost by ammonia volatilization if precautions are not taken.  The best solution
for minimizing ammonia loss is to incorporate or place ammonium compounds approxi-
mately 10 cm below relatively dry surface soil.  The volatile products of denitri-
fication, nitrous oxide and nitrogen gas, may be lost from the soil whenever the
soil becomes wet enough that oxygen becomes depleted and sufficient carbon is
available from organic materials to support microbial activity.  Denitrification
occurs significantly only over a very narrow soil-water content range near
saturation and in those portions of the soil profile with fairly high organic
material.  Consequently, denitrification will generally only occur in the surface
60 cm of most soils of arid regions unless perched water tables exist at a buried
surface horizon.  Management practices to either minimize or maximize denitrifi-
cation should be directed at controlling nitrate position and water content in the
surface soil.


78:03F-018
REMOVAL OF NITROGEN BY VARIOUS IRRIGATED CROPS,
Tucker, T.C., and Hauck, R.D.
Arizona University, Tucson, Department of Soils, Water and Engineering.
Proceedings of National Conference on Management of Nitrogen in Irrigated Agri-
culture, California University, Sacramento, California, p 135-167, May 15-18,
1978.  2 fig, 7 tab, 16 ref.

Descriptors:  Nitrogen, Nutrient removal, Crop production, Fertilizers, Soil
management.

Harvested agronomic and horticultural plants, excluding rice,  are grown under
irrigation on over 16 million hectares of land in 33 states.  Results of a
survey of published and recent unpublished information on removal of soil and
fertilizer nitrogen from irrigated land in the harvested portion of crops was
presented.  The amount of nitrogen removed varied considerably among different
plant species and within the same species when grown under widely different manage-
ment and environmental conditions.  The amount of fertilizer nitrogen apparently
removed by grain crops generally was within the average range for all crops, 40
to 60% of the nitrogen applied.  Fertilizer efficiency is discussed from three


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 main viewpoints:  in terms of (1)  the amount of applied nitrogen found in the
 plant, (2)  the yield of harvested plant parts in relation to amount of fertilizer
 nitrogen applied, and (3)  the cash value of marketable crop in relation to nitro-
 gen cost.  Examples are given, using data for coastal bermudagrass and wheat, pf
 fertilizer efficiency as calculated on the basis of these viewpoints.   Methodo-
 logical problems of collecting data and problems of data interpretation are dis-
 cussed in relation to the several concepts of fertilizer efficiency,  and emphasis
 is placed on the need to recognize the role of all soil, fertilizer,  and crop
 management factors in determining the efficiency by which plants use nitrogen^.


 78:03F-019
 THE INDISPENSABLE ROLE OF NITROGEN IN AGRICULTURAL PRODUCTION,
 Olson, R.A.
 Nebraska University,  Lincoln,  Department of Agronomy.
 Proceedings  of National Conference on Management of Nitrogen in Irrigated Agri-
 culture,  California University,  Sacramento,  California,  p 1-31, May 15-18,
 1978.   10 fig,  2 tab,  35 ref.

 Descriptors:   Nitrogen,  Fertilizers,  Nutrients,  Crop production, Crop  response,
 Pollutants.

 The indispensable role of nitrogen in food and fiber production for the world's
 people cannot be disputed.   There  is  no substitute for nitrogen in its essential
 roles  as  a component of the chlorophyll and protein constituents of crop plants.
 The quantity required for  obtaining an economic yield of most crops exceeds that
 of all other  soil-derived essential nutrients.   The advent of relatively cheap
 fertilizer nitrogen in the 1950's  caused radical increases in yields obtainable
 with most crops in the developed countries and provided the spark that ignited
 the Green Revolution in many of  the Less Developed Countries in the 1960's  as
 well.   Its preeminence in the  food production chain notwithstanding, nitrogen has
 been subjected recently to more  critical surveillance than any other element in
 agriculture by reason of energy  expended in its  conversion into fertilizers,  its
 monetary  cost to the farmer,  and its  potential  role as environmental pollutant.
 The economic  and environmental problems can be minimized,  however,  by  matching
 rate and  timing of applied nitrogen with the amount likely to be provided the
 soil during  the growing  season and with the water regime afforded.  The agricultur-
al sector must achieve this matching objective promptly if it is not to be
 condemned by  the rest of society in the long term.


 78:03F-020
 ASSESSING THE SPATIAL  VARIABILITY  OF  IRRIGATION  WATER APPLICATIONS,
 Karmeli,  D.,  Salazar,  L.J.,  and  Walker,  W.R.
 Colorado  State  University,  Fort  Collins,  Colorado,  Department of Agricultural
 and Chemical  Engineering.
 Publication No.  EPA-600/2-78-041,  March,  1978.   201 p,  38  fig,  25 tab,  71 ref,
 6  append.

 Descriptors:   Irrigation,  Efficiency,  Sprinkler  irrigation.

 The current state of  the art regarding the spatial  distributions of irrigation
 water  applications under surface,  sprinkler,  and trickle irrigation systems  has
 been assessed.   The analyses found in  the literature and several new uniformity
 concepts  have been integrated  into models which  can be used in both field and
 research  applications.   These  models  stimulate the  spatial distributions of  applied
 irrigation wat'er under specified design and  operating  conditions.   The  performance
 of an  irrigation system  has been described by a  series of  "quality" parameters
 relating  to:   (1)  uniformity in  an irrigated field;  (2)  adequacy of the irrigation
 system in meeting crop requirements;  (3)  volume  of  applied water wasted as  deep
 percolation;  and (4) in  the case of surface  irrigation,  the water leaving the
 field  as  tailwater.  Verification  of the  models  developed  during this project was
 made against most of tfte data  identified  in  the  literature as well  as  an intensive
 collection effort as part of this  project.   The  results  illustrate  both the  use
 of the analytical approach and the procedures for field  data collection.
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 78:03F-021
 RELATIVE EVALUATION OF WATER STRESS INDICATORS FOR SOYBEANS,
 Sivakumar, M.V.K., and Shaw, R.H.
 International Crops Research Institute for Semi-Arid Tropics,  Hyderabad 500 016,
 India.
 Agronomy Journal,  Vol. 70,  No.  4,  p 619-623,  July-August,  1978.   7 fig,  1 tab,  23
 ref,  1  egu.

 Descriptors:   Soybeans, Soil-water-plant relationships,  Moisture stress,  Moisture
 deficit, Growth rates, Plant growth,  Soil water,  Iowa,  Indicators.

 Field studies were conducted during 1976 on Ida silt loam  (fine,  silty, mixed
 (calcareous)  mesic family of Typic Udorthents)  at the Western  Iowa Experimental
 Farm, Castana, Iowa,  to evaluate three plant  measurements  (vis.,  stomatal conduct-
 ance, leaf-water potential,  and leaf  area)  as water stress  indicators  for soybeans
 (Glycine max  (L.)  Merr.).  Daily means of stomatal conductance and leaf-water
 potential measured several  times during the growing season  were  closely related
 to changes in soil-water potential.  "Rate of leaf-area  expansion" which  is
 defined as the change in average leaf area (leaf  area/number of  leaves) per plant
 over  a  period of time, also  showed a  close correspondence with soil-water potential.
 Relative growth rates of soybeans showed a negative correlation  with stomatal con-
 ductance, leaf-water potential, and rate of leaf-area expansion.   The  three plant
 measurements  should prove useful in explaining water-deficit effects quantitatively
 under field conditions.


 78:03F-022
 ACCUMULATION  AND REDISTRIBUTION PATTERN OF DRY MATTER AND N IN TRITICALE  AND WHEAT
 VARIETIES UNDER WATER STRESS CONDITION,
 Lai,  P.,  Reddy,  G.G.,  and Modi,  M.S.
 California University, Davis, Department of Land,  Air and Water Resources.
 Agronomy Journal,  Vol. 70, No.  4,  p 623-626,  July-August, 1978.   1 fig, 3 tab,  16
 ref.

 Descriptors:   Cereal  crops,  Wheat,  Moisture stress,  Varieties, Nitrogen,  Economic
 efficiency, Translocation, Moisture deficit,  Crop  production,  Grains (crops).

 The objective of this  study  was to  screen varieties  of triticale  (Triticale  hexa-
 ploide  Lar.)  relative  to  wheat  (Triticum aestivum  L.) for their high translocation
 ability  and N utilization efficiency.   A field  experiment was  conducted on  silt
 loam  soil (Typic Hapludoll)  during  1973-74  at Pantnagar, India.   Treatments  con-
 sisting  of five  varieties each  of  triticale and wheat were  arranged  in a  randomized
 block design  with  five replications.   Plant samples  were collected from a 0.125-sq
 m  area  for dry matter  and N  content studies in  culm,  lower  leaf,  flag leaf,  spike
 chaff,  and grain at successive  stages.   The loss of  dry matter from different plant
 parts was assumed  to be translocated  to  the grains.   Both triticale and wheat
 cultivars differed greatly in their capacity  to accumulate  and redistribute  dry
 matter and N.  On  an average, triticale  cultivars  removed larger  amounts  of  N than
 the wheat.


 78:03F-023
 INFLUENCE ON  MANURE APPLICATION RATES  AND CONTINUOUS  CORN ON SOIL-N,
 Magdoff,  F.R.
 Vermont  University, Burlington,  Department  of Plant  and Soil Science.
 Agronomy  Journal,  Vol.  70, No.  4, p 629-632,  July-August, 1978.   2 tab, 18 ref,
 6  equ.

 Descriptors:   Corn(field), Decomposing organic  matter, Organic matter, Nitrogen,
 Crop  response, Nutrient requirements,  Rates of  application, Sites.

 The manure-N  experiments with continuous  corn (Zea mays L.)  were  conducted on both
 a  somewhat poorly  drained Panton clay  (Typic  Ochraqualf) and a well-drained Calais
 loam  (Typic Fragiorthod).  Manure rates of  0,  22,  44, and 66 metric tons/ha/year
were combined  in factorial arrangement with ammonium  nitrate rates of 0,  112, and
 224 kg N/ha/year.  Comparison of calculated theoretical soil-N with experimentally
 determined levels  after five years and the  response of corn to fertilizer-N  indi-
 cate that mineralization of manure organic-N,  when applied  to the Panton  clay, was
 less than when applied  to the Calais loam.  Thus, manure-N was less available to
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 the  growing  crop  on  the  clay -and  accumulated  in  the  soil  at  a greater  rate  than
 in the  loam.   The annual manure application rates  required to maintain initial
 soil N  levels  in  Panton  clay  and  Calais  loam  under continuous corn  production were
 calculated to  be  40  to 52  tons/ha respectively.  Two mineralization models  were
 examined:  Model  1 assumed only the  first year manure mineralization rate above
 native  soil  organic  matter decomposition rate; Model 2 assumed  a  five-year
 mineralization decay series.  Both were  effective  in predicting final  soil-N
 levels.


 78:03F-024
 INFLUENCE OF FERTILIZER  AND RESIDUE  MANAGEMENT ON  GRASS SEED PRODUCTION,
 Canode, C.L.,  and Law, A.G.
 Washington State  University,  Pullman, Department of  Agronomy.
 Agronomy Journal,  Vol. 70, No. 4,  p  543-546,  July-August, 1978.   3  tab, 8 ref.

 Descriptors:   Grasses, Wheatgrass, Fescues, Bromegrass, Fertilization,  Burning,
 Air  pollution.

 The  experiments were conducted on a  silt loam soil (Pachi Ultic Haploxerolls) as
 a split-plot within  each grass species.  Main plots  were  three  levels  of 18-10-
 10-7 fertilizer applied  to supply N  at 90, 112,  and  135 kg/ha,  with an associated
 increase in  P, K,  and S.   Main plots were split  for  open burning  and two levels
 of mechanical  residue removal.  Two  crops of  red fescue and  four  seed  crops of
 smooth bromegrass  and crested wheatgrass were evaluated.  Average seed  yields
 (kg/ha) for  burning  compared  with  mechanical  straw removal were 636 vs. 495 for
 red  fescue,  1,122  vs. 848  for smooth bromegrass, and 872 vs. 790  for crested
 wheatgrass.  Interactions  of  fertilizer  rates and  residue management were not
 significant.   The  increase in seed production resulting from burning residue
 apparently was associated  with control of downy  bromegrass (Bromus  tectorum L.)
 and  increased  vigor  of autumn growth.


 78:03F-025
 RESPONSE OF  CORN TO  ZN IN  ORTHO- AND PYROPHOSPHATE FERTILIZERS, AS  AFFECTED BY
 SOIL TEMPERATURE AND MOISTURE,
 Giordano, P.M., and  Mortvedt, J.J.
 National Fertilizer  Development Center,  Tennessee Valley Authority, Muscle Shoals,
 Alabama, Soil  and  Fertilizer  Research Branch.
 Agronomy Journal,  Vol. 70, No. 4,  p  531-534,  July-August, 1978.   2  fig, 2 tab,
 8 ref.

 Descriptors:-  Fertilizers, Phosphates, Sweet  corn. Zinc, Phosphorus, Soil moisture,
 Soil  temperature,  Crop response, Plant growth.

 The  purpose of this  investigation was to determine the effects  of both  soil
 temperature and moisture regimes on  the  uptake of  Zn and P by corn  (Zea mays L.)
 from ZnS04, granulated with ammonium ortho- and polyphosphate fertilizers and
 applied to Nolichucky scl  (pH 7.6), a Typic Paleudult soil.  In a series of green-
 house experiments, corn grown under various soil temperature (16  to 32 C)  and
 moisture regimes  (0.3 to 0.15 atm) showed a marked reduction in dry matter yield,
 as well as in  Zn and P uptake, at  low temperature, but varying  soil moisture levels
 had  little effect.   Uptake of Zn was greater when triammonium pyrophosphate rather
 than monoammonium phosphate was the source of applied P, but uptake of P-from
 the  two P sources was comparable.  Although lower Zn uptake appears to be a
 function of depressed growth under cool soil  conditions, it is  likely that
 deficiency arises because early Zn requirements cannot be met when  the available
 Zn supply is low.  Uptake and yield results further suggest that  early growth
 retardation sometimes attributed to Zn deficiency during cool springs also may
 be related to suppression of P uptake.


 78.-03F-026
 RADIATION AND ENERGY BALANCE ON A TRICKLE-IRRIGATED LEMON GROVE,
Ben-Asher, J.,  and Sammis, T.W.
Arizona University, Tucson, Water Resources Research Institute.
Agronomy Journal, Vol. 70, No. 4, p 568-572, July-August, 1978.    4  fig, 2 tab,
 7 ref, 7 equ.
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 Descriptors:   Water conservation,  Irrigation,  Irrigation  systems, Energy budget,
 Evapotranspiration, Lemons,  Albedo,  Radiation.

 This study  was conducted to  evaluate the water  saving potential  and  evapotranspi-
 ration from a trickle irrigated lemon grove  (Citrus  limon L.  "Lisbon").  Detailed
 measurements  of global,  reflected,  and net radiation and  its  dissipation above
 the plant,  the unshaded  sandy  soil,  and the  area  as  a whole were made  in the
 spring and  summer  of 1975.   Two sources of radiant energy were observed:   net
 radiation which accounted for  70%  of the energy utilized  in evapotranspiration
 and reflected radiation  from the unshaded  soil  accounting for 30%.   Experimentally
 the net radiation  and evapotranspiration of  the wet  complex increased  as the
 average net radiation and the  evapotranspiration  from the area as a  whole  de-
 creased and vice versa.   On  the other hand,  evapotranspiration and its ratio to
 evaporation from a class A pan were  smaller  than  any previously  reported values.
 Therefore,  it is suggested that for  these  two periods the contribution of  energy
 from the dry  area  to the wet did not reflect a  specific disadvantage for trickle
 irrigation.


 78:03P-027
 YIELDS,  NUTRIENT REMOVAL,  AND  NUTRIENT CONCENTRATIONS OF  DOUBLE-CROPPED CORN
 AND SMALL GRAIN SILAGE,
 Murdock,  L.W.,  and Wells,  K.L.
 Kentucky University,  Lexington,  Department of Agronomy.
 Agronomy Journal,  Vol. 70, No.  4, p  573-576, July-August,  1978.  7 tab, 7  ref.

 Descriptors:   Sweet corn,  Barley, Oats,  Silage, Crop response, Crop  production,
 Nutrient removal,  Kentucky.

 The study was initiated  to determine production levels from double-cropped silage,
 the most compatible small  grain species  for  double-cropped silage, and the rate
 and method  of fertilizer application needed  for high production.  Field experiments
 were established on Huntington (fine-silty,  mixed mesic fluventic Hapludoll) and
 Pope (coarse-loamy,  mixed, mesic fluventic Dystrochrept)  soils.  Three fertility
 levels were tested with  392-128-280,  280-89-232, or  168-54-140 kg/ha of N-P-K
 being applied each year.   Single and split applications of K were studied.  Barley
 (Hordeum vulgare L.)  and oats  (Avena sativa  L.) were compared as small grain
 species.  This  study indicates  that  double-cropped corn and small grain for
 silage can  result  in substantially higher  dry matter production  per unit land
 area than single-cropped corn.   Large amounts of minerals  are removed, however,
 particularly  K,  by the small grain component of the  double-cropping system.


 78:03F-028
 SUGAR BEET  GENOTYPE,  N,  AND SOIL MOISTURE  AVAILABILITY INTERACTIONS IN COMPONENTS
 OF  BEET  YIELD AND  QUALITY,
 James,  D.W.,  Doney,  D.L., Theurer, J.C., and Hurst,  R.L.
 Utah State  University, Logan,  Department of  Applied  Statistics and Computer Science.
 Agronomy Journal,  Vol. 70, No.  4, p  525-531, July-August,  1978.   8 fig, 2  tab,
 16  ref.

 Descriptors:  Sugar beets, Nitrogen,  Soil moisture.  Crop response, Crop production,
 Varieties.

 This study was  conducted to investigate the  genotype of sugar beet (Beta vulgaris
 L.)  X soil N  and genotype X soil water interaction from a broad genetic base.
 A series  of 20  genetically different  genotypes differing in yield, sugar percent,
 and  impurity  index potential were field tested  in 1974 at  four N levels:   0, 84,
 210,  and  525  kg/ha.   In  1975, eight  genetically diverse genotypes were field
 tested at five  N levels and four irrigation  levels.  The soil type was coarse,
 loamy mixed mesic  family of calcic haploxerolls.  Analysis of data were for root
 yield,   sucrose percent,  gross sugar, and  impurity index,   Highly significant
main  effects  due to N in 1974 and 1975 and water in  1975 were observed for all
measured  parameters.  A significant genotype (V) X (N)  interaction was obtained in
 1974  for  all  parameters.   There was an apparent genotype X water interaction in
 1975; however,  unbiased statistical inferences could not be made because of the
 experimental  design.  These interactions indicate that genetic variation exists
 such  that new cultivars may be developed that give high sugar production at low
N levels  or are  not affected adversely in quality at a high N level.


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 78:03F-029
 INHIBITION  OF  UREASE  ACTIVITY BY  HETEROCYCLIC  SULFUR  COMPOUNDS,
 Gould,  W.D., Cook,  F.D.,  and Bulat,  J.A.
 Alberta University, T6G  2E1, Edmonton, Alberta,  Canada,  Department of Soil Science.
 Soil  Science Society  of  America Journal, Vol.  42, No.  1, p  66-71, January-February,
 1978.   3 fig,  5  tab,  30  ref.

 Descriptors:   Urea, Nitrogen, Nitrification, Inhibitors, Sulfur compounds. Soil
 investigations,  Volatility, Hydrolysis.

 The inhibition of both jack bean  urease and soil urease  by  several heterocyclic
 mercaptans  was investigated.  The following compounds  not previously tested as
 urease  inhibitors were found to be effective inhibitors  of  jack bean urease:
 1,3,4-thiadiazole-2,5-dithiol; 5-mercapto-3-phenyl-l,3,4-thiadiazole-2-thione;
 and 5-amino-l,3,4-thiadiazole-2-thiol.  The disulfides of the  latter two com-
 pounds  were found to  be  very potent  inhibitors of jack bean urease.  The results
 are consistent with an inhibition mechanism involving  a  thiol-disulfide exchange
 reaction between a disulfide and  one or more of  the sulfhydryl groups of urease.
 The results also imply that inhibition of urease by the  heterocyclic mercaptans
 was due to  trace amounts  of the corresponding  disulfides or polysulfides in the
 mercaptan preparations.   A number of heterocyclic mercaptans,  two disulfides,
 and a number of  known urease inhibitors were evaluated as soil urease inhibitors,
 and the following compounds were  the most effective:   1,4-benzoquinone; hydro-
 guinone > 2,5-dimethyl-1,4-benzoquinone; catechol; 1,3,4-thiadiazole-2,5-dithiol;
 2,6-dimethy1-1,4-benzoquinone.


 78:03F-030
 NONUNIFORM  SPRINKLER  IRRIGATION APPLICATION EFFICIENCY,
 Chaudhry, F.H.
 de Sao  Paulo Universidade, Sao Carlos, Brazil, Department of Hydraulics and
 Sanitary Engineering.
 Journal of  the Irrigation and Drainage Division, American Society of Civil
 Engineers,  Vol.  104,  No.  IR2, p 165-178, June, 1978.   4  fig, 15 ref, 43 equ,
 3  append.

 Descriptors:   Irrigation  efficiency, Sprinkler irrigation,  Uniformity coefficient,
 Distribution,  Statistical methods, Irrigation, Irrigation design.

 Application efficiency offers a physically significant characterization of
 nonuniform  irrigation which can help in striking a balance  between the cost of
 maintaining higher uniformity and  the cost of water.   This  paper quantifies the
 role of asymmetry in  the  various  efficiency parameters of nonuniform irrigation
 representing its areal pattern by  a  skew distribution.  It  is  shown that if the
 application ratio or  the  coefficient of variation, or  both, are small, the appli-
 cation  efficiency approaches the value of the application ratio.  The equality
 between the application ratio and  the application efficiency can be obtained at
 relatively  larger coefficients of  variation (or  smaller uniformity coefficients)
 for positively skewed distributions.  Given the  statistical properties of the
 sprinkler or surface  irrigation distribution and the proposed  application ratio,
 the results of this study should permit a more accurate evaluation of the appli-
 cation  efficiency and thus of the  economics of the proposed installations.


 78:03F-031
 EFFECT  OF IRRIGATION  REGIME ON MAIZE YIELDS,
 Barrett,  J.W.H.,  and  Skogerboe, G.V.
 Colorado  State University, Fort Collins, Department of Agriculture and Chemical
 Engineering.
 Journal  of  the Irrigation and Drainage Division, American Society of Civil Engineers/
Vol. 104, No.   IR2, p  179-194, June,  1978.   9 fig, 2 tab, 20 ref, 1 append.

 Descriptors:  Yield equations,  Sweet corn, Crop  response, Moisture stress,  Water
 requirements,  Growth  stages, Evapotranspiration, Crop production, Irrigation,
 Irrigation  efficiency.

 To determine the economically optimal allocation of irrigation water to a given
 crop,  the relationship between the yield of the crop and its use of the supplied
water must be known.  Different shapes of the function relating yield to water


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use have been obtained by various researchers.  The strongly linear relationship
between wheat grain yield and precipitation  has been supported by container and
field experiments that have demonstrated for many crops a linear relationship
between yield and water use until maximum- yield is obtained.  The purpose of
this paper is to present field  evidence substantiating the form of the crop
yield-water use function and to demonstrate the effects of different irrigation
regimes on the yield of corn.


78:03F-032
WATER TREATMENTS IN TRICKLE IRRIGATION SYSTEMS,
Nakayama, F.S., Gilbert, R.G., and Bucks, D.A.
Agricultural Research Service, Phoenix, Arizona, Department of Agriculture.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 104, No. IRl, p 23-34, March, 1978.  11 fig, 1 tab, 12 ref, 1
append.

Descriptors:  Irrigation water, Water treatment, Irrigation systems, Clogging,
Orifices, Water quality, Water analysis, Water pollution control, Filtration,
Colorado River.

A comprehensive two-year study on trickle irrigation systems using Colorado River
water in southwestern Arizona has shown that adequate water filtration is a primary
requirement for reliable emitter operation.  Filtration systems must be able to
handle local peak loads in suspended particulates from the source water.  For
the long-term operation of the trickle system, the practice of flushing mains,
submains and lateral lines, and chemical water treatment is essential for control-
ling the buildup of sediment, precipitates, and microbial slime.  Precautions
must be taken to ensure that the emitters,  line materials, and other equipment
are resistant to chemicals such as fertilizer, bactericide, insecticide, and
herbicide that may be injected into the system.


78:03F-033
BASIC IRRIGATION SCHEDULING PROCEDURES,
Fischbach, P.E.
Nebraska University, Lincoln, Department of Agricultural Engineering.
Irrigation Age, Vol. 12, No. 7,  p 66-67, April, 1978.  2 fig.

Descriptors:  Irrigation, Irrigation water, Scheduling, Soil moisture, Moisture
content, Growth stages, Sweet corn. Moisture meters, Evapotranspiration, Water
conservation.

On a fine textured deep soil, four basic irrigation scheduling procedures were
compared on corn.   The procedures consisted of irrigations according to (1) the
calculated crop water use, (2)- the average electrical resistance block reaching,
(3) the soil moisture content (feel method) at three stages of growth of the
corn plant, and (4)  a predetermined range of net water application every fourteen
days.  The difference between grain corn yields were not significant at the 5%
level between scheduling procedures.  The least effort to schedule irrigations
was with the electrical resistance blocks.   Applying only 2 inches of net irri-
gation water or less each irrigation is important so that nitrogen, water or
energy is not wasted.  Using a water measuring meter to know how much water was
applied appears to be the most critical measurement to save nitrogen, water and
energy.


78:03F-034
ON-FARM LEVEL-BASIN IRRIGATION—SAVE WATER AND ENERGY,
Dedrick, A.R., Replogle, J.A., and Erie, L.J.
Agricultural Research Service, Phoenix, Arizona, U.S. Department of Agriculture.
Civil Engineering, Vol. 48, No. 1, p 60-65, January, 1978.  8 fig.

Descriptors:  Surface irrigation, "Basins, Irrigation efficiency, Irrigation
systems, Irrigation practices, Water distribution (applied), Energy loss, Water
conservation, Automation.

Spiraling energy costs, and the doubtful availability of electricity or natural
gas for pumping, stand as a serious threat to future high-energy-consuming water


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application  techniques.  Even with the growing concern for water conservation,
we may  run out of energy before we run out of water.  Surface irrigation,
because of its lower energy requirements, deserve renewed attention.  Thus,
despite the  merits of sprinkler and trickle irrigation, conversion from surface
irrigation should be approached cautiously, especially where properly designed
surface irrigation techniques are suitable.  Uniformity of application and
resultant minimal water loss over the irrigated area are prime criteria of an
irrigation system.  These can be attained with level basins by balancing the
basin size to the irrigation water supply and soil intake characteristics.
The key factors in boosting irrigation efficiencies are suggested as:  (1)
using lasers to make the farm field as level as possible, (2) using special
flumes  and weirs to measure water flow, and (3) using automated gates to control
the amount of water applied to a field.


78:03F-035
TAILWATER PITS GAIN POPULARITY IN TEXAS,
Blair,  J.
Big Spring,  Texas.
Irrigation Age, Vol. 12, No. 7, p 70-71, April, 1978.  4 fig.

Descriptors:  Tailwater, Silts, Irrigation, Water conservation, Irrigation
practices, Crop production, Water shortage.

Tailwater pits are one of the best methods yet devised to save irrigation water
on the  hardlands of northwest Texas and eastern New Mexico.   Interest in them
is still high, though the construction rate has slowed because of rising costs
and the increase in sprinkler systems.  In the recent years tailwater pits are
designed according to the size of the field and amount of expected runoff with
efficient silt traps.  The report also suggests to check pump and motor
occasionally to increase their efficiencies.  It also suggests to irrigate alter-
nate rows, learn when the crops go through stress periods, use limited tillage
to'reduce evaporation, improve tillage to reduce fuel costs, grow crops that
use less water, and go back to terracing the fields if necessary.


78:03F-036
"NO ROOM FOR ERROR" SAYS YOUNG IRRIGATOR,
Irrigation Age, Vol. 12, No. 5, p 77, February, 1978.

Descriptors:  Crop production, Management, Agriculture, Idaho, Potatoes,
Fertilizers, Herbicides, Pesticides-
          *
The total management approach towards agricultural crop production of a Idaho
farmer was discussed.  The approach includes frequent soil and plant testing,
selection of good seed varieties, timely applications of fertilizers, herbicides,
and pesticides of the right kind and amount including a good crop rotation program.


78:03F-037
STUBBLE BURN SCORES,
Irrigation Age, Vol. 12, No. 4, p 16, January, 1978.

Descriptors:  Burning, Infiltration, Infiltration rates, Crop production-, Econo-
mics,  Adoption of practices, Comparative benefits, Comparative costs, Comparative
productivity.

A study conducted at Texas A & M University compared plots where the straw was
worked, where it was removed by bailing and where the straw and stubble was burnt
off.  The results showed that the difference in yields from the three types of
plots was statistically insignificant.  But the calculated annual savings from
burning off each year rather than bailing or working back into the soil was $4.02/
acre;  whereas burning every other year and every third year could save $2.01 and
$1.34/acre  respectively.  Another study involving infiltration rate showed that
the infiltration rate for the burnt area was. slower in the first hour, but in-
creased later during a 22-hour-period..  Total infiltration for the period for
the plot with straw worked in was 2.58 inches compared with 2.50 for straw
removed and 2.28 inches for the burned area.  The effect of straw disposal treat-
ments on soil structure including changes in soil aggregates, bulk density,
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gas,
organic matter and compaction was studied.  Results of dry and wet sieve
analyses showed no significant differences among the three treatments.


78:03F-038
NEW MEXICO PUMP STUDY POINTS TO FARMERS' NEED FOR EFFICIENCY KNOWLEDGE,
Irrigation Age, Vol. 12, No. 4, p 34-35, 58, January, 1978.  3 tab.

Descriptors:  Pump testing, Pumping plants, Pumps, Efficiencies, Natural
Operation and maintenance, New Mexico.

A New Mexico irrigation pump study suggests farmers should know more about
pump efficiency and should have expert help in selecting pumps.  Overall effi-
ciency of a pumping plant, according to the report, should range from 15 to
20%.  A study conducted by Texas Tech College which covered power requirements
and efficiencies of 46 natural gas pumps revealed that only € pumps exceeded
15% overall efficiency while 16 had overall efficiencies below 10% and the
average was 10.7%.  The study conducted in New Mexico suggested that the average
pump efficiency could be improved to 15% and thereby about 1.4 million cubic
feet of natural gas used for irrigation pumping during an average year in New
Mexico could be saved.  This report also provides some guidelines for studying
pumping plant efficiency.


78:03F-039
TENSIOMETERS TEACH HOW TO SAVE FUEL AND WATER,
Rodgers, N.
Littlefield, Texas.
Irrigation Age, Vol. 12, No. 4, p 45-46, January, 1978.

Descriptors:  Tensiometers, Equipment, Data collections, Irrigation, Irrigation
efficiency, Soil moisture, Moisture tension, Moisture content, Water conservation.

Tensiometers axe valuable tools for the irrigator helping him to save money and
water during the irrigation season.  The irrigation schedule, based on soil
moisture tension, can be varied during different periods of the growing season,
depending upon the water requirements of the plant.  However, they can mislead
the irrigator if the tensiometers are not properly placed and maintained.
Reading tensiometers daily has been suggested since it will indicate the danger
of the tensiometers breaking suction and thus taking false readings can be
avoided.


78:03F-040
DRAINAGE AND THE CENTER PIVOT SPRINKLER METHOD OF IRRIGATION,
Alvi, A.A.
Valmont International, Valley, Nebraska  68064.
ICID Bulletin, Vol. 27, No. 1, p 76-78, January, 1978.  7 ref.

Descriptors:  Sprinkler irrigation, Irrigation, Drainage, Flooding, Salinity.

The surface method of flood irrigation is a source of drainage problems and it
also does not provide controlled amounts of water to crops as and when required.
The Center Pivot Sprinkler method of irrigation helps to solve these problems
and has some other additional advantages.  This method of irrigation in combina-
tion with integrated drainage construction is hoped to meet growing needs of
food and fiber for the increasing world population.


78:03F-041
DEVELOPMENT OF AGRICULTURAL IRRIGATION IN THE FEDERAL REPUBLIC OF GERMANY,
Zanker, K.
Federal Ministry sof Food, Agriculture and Forestry, Bonn, Regierungsdirektor.
ICID Bulletin, Vol. 27, No. 1, p 85-88, January, 1978.  3 tab, 4 ref.

Descriptors:  Irrigation, Irrigation systems, Sprinkler irrigation. Water
conservation. Water shortage, Arid climates, Semiarid climates.

Although the Federal Republic of Germany is situated in the temperate zone and
owing to its quite high rainfall has no real water shortage in the strict sense

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 of the term,  modern irrigation methods  do,  however,  offer the possibility of doina
 the available water supply more rationally  and more  economically.   This  is parti-
 cularly true  for years with low rainfall.   In granting new water rights,
 the authorities should strive to reserve  the  supply  of groundwater  primarily for
 drinking purposes.   In most cases for irrigation,  surface water or  effluent is
 sufficient (the latter,  of course,  subject  to standards of hygiene  being  met).
 The results of the  present paper can  be usefully  applied to areas where a real
 water  shortage exists-arid and semi-arid  zones of  the  earth.   The more economical
 use of water  available,  made possible by  more modern irrigation methods,  which
 can lead to a considerable saving of  water, can be of  great importance, especially
 when water is in particularly short supply.


 78:03F-042
 STANDARDS  FOR THE CALCULATION OF IRRIGATION EFFICIENCIES,
 ICID Committee on "Assembling Irrigation  Efficiency  Data."
 ICID Bulletin,  Vol.  27,  No.  1,  p 91-101,  January,  1978.   6  tab, 6 egu.

 Descriptors:   Standards,  Irrigation efficiency, Irrigation,  Irrigation ditches,
 Irrigation canals,  Irrigated land,  Irrigation design.

 The efficient management of irrigation  water  is becoming more and more important
 as  the competition  for water of good  quality  grows ever keener with the world's
 increasing population.   Reliable measurements of water are  vital in preventing
 wastage and in the  attainment of maximum  beneficial  use.   Measurements should be
 made and records kept  of  all water  flowing  into and  through the supply system and
 of  all deliveries made from the system.   Discharge measurements should be  made
 as  accurately as is  practicable and action  should  be taken  to restrain overdelivery-
 The purpose of this  paper is to lay down  a  standard  procedure for assessing
 efficiency of water  use  in conveyance,  distribution  and field application  operations-


 78:03F-043
 DRIP SYSTEMS  STANDARDS AND SPECIFICATIONS,
 Irrigation Journal,  Vol.  28,  No.  3, p 12-13,  32, May-June,  1978.

 Descriptors:   standards,  Specifications,  Irrigation, Irrigation systems, Water
 conservation,  Irrigation  design,  Installation.

 These  standards  and  specifications  of drip  irrigation  systems  outlined by  the
 Florida  Irrigation Society contains useful  information and  guidelines for  the
 irrigation industry.


 78:03F-044
 UNDER-TREE IRRIGATION  SYSTEM,
 Irrigation Journal, Vol.  28,  No.  3, p 34, May-June, 1978.

 Descriptors:   Irrigation,  Water  conservation,  Irrigation systems,  Sprinkler
 irrigation, Drainage, Leaching.

A paper  entitled, "Irrigation in Ihe 21st Century-Today," which appeared in the
May/June 1976  issue of the Irrigation Journal, dealt with the  advantages of the
Micro  Jet  and referred to  it as  the irrigation system of the  future.  The purpose
of this  paper is  to describe an  Israeli emitter, or minisprinkler which has been
in operation  for  a number  of years and also shows a great potential for the
future.


78:03F-045
DRIP AND/OR SPRINKLER,
Olson,  B.R., Jr.
Olson Engineering System,  Indio, California.
Irrigation Journal,  Vol.  28, No. 3, p 46-47, May-June,  1978.

Descriptors:  Water conservation, Irrigation systems, Sprinkler irrigation, Water
management  (applied), Irrigation water,  Filtration.

The purpose of this  report is to discuss the various aspects of a  drip irrigation
system associated with its applicability and how it compares with  a sprinkler
irrigation system.
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  78:03F-046
  COMPUTER SCHEDULING CAN SAVE MORE WATER,
  Irrigation Age, Vol. 12, No. 6, p 17, March, 1978.

  Descriptors:  Irrigation programs, Scheduling, Irrigation efficiency, Water
  conservation, Computer models, Computer programs, Water management  (applied),
  Nebraska, Irrigation systems.

  It is reported that scheduling of irrigation water application through the use
  of electrical resistance blocks to determine soil moisture content, with data
  feedback to a computer system, can save up to 38% of the water and energy being
  used in most irrigation operations without reducing yields.  One such irrigation
  scheduling computer program developed at the University of Nebraska-Lincoln has
  been discussed in this report.


  78:03F-047
 BETTER WATER USE,  SAYS TEXANS,
 Blair,  J.
 Big Spring,  Texas.
 Irrigation Age,  Vol.  12,  No. 6, p 26, March, 1978.

 Descriptors:   Water conservation,  Irrigation,  Irrigation wells,  Texas,  Irrigation
 efficiency,  Grain sorghum,  Cotton,  Drought resistance,  Surface irrigation,
 Sprinkler irrigation.

 Irrigation on the Southern  High Plains will continue the trends  started a few
 years ago when production costs escalated.   There will  be greater emphasis  on
 irrigation efficiency,  more timely  watering,  fewer irrigations,  and a slow-down
 in buying of  new equipment.  Also  there will be a shift in crop  acreages, with
 some  of the  corn and wheat  land being put  in milo and cotton.  Consensus  of
 opinion of the farmers  is that  despite higher  irrigation costs most farmers will
 pump  the wells in  1978.  But there  will be  continued improvement in pumping effi-
 ciency,  more  water conservation methods used, more dependence  on rainfall and
 a shift to drought resistant crops,  such as cotton and  grain sorghum.


 78:03P-048
 CORN  YIELDS FROM IRRIGATION WITH ADEQUATE AND DEFICIENT WATER,
 Kroutil, W.F.
 Nebraska University, North  Platte,  Department of  Agricultural  Engineering.
 Paper No.  78-2555,  Presented at the  1978 Winter Meeting of the American Society
 of Agricultural  Engineers,  December  18-20,  1978,  Palmer House  Hotel, Chicago,
 Illinois, 19  p.  11 fig, 2  tab,  25  ref.

 Descriptors:  Water management "(applied), Corn (field), Moisture deficit, Yield
 equations, Crop  response, Crop  production,  Growth stages, Evapotranspiration,
 Water conservation, Irrigation  efficiency.

 In 1974  and 1975,  the effects of varying the time and the amounts of applied
 irrigation water on corn yield .was studied  on field plots at Fort Collins,
 Colorado.  A single irrigation  sprinkler line extending through the center of
 each  plot provided the sole  source of  irrigation water.   With  this irrigation
 design,  the corn experienced greater water  deficiency outward  from the sprinkler
 line. . In addition, irrigation water was withheld  from some treatments during
 various growth periods throughout the  season.  The field plots were preplant
 irrigatdd to wet the soil profile to a depth in excess of three meters.   Primary
 comparisons were made of actual and/or relative yields of grain and dry matter
 for different water application amounts and for evapotranspiration.  Omitting
 irrigation water during certain growth periods generally reduced yields.  High
 soil water holding capacity reduced the necessity for frequent irrigation.
 Omitting all irrigations during two growth periods reduced yields substantially.
 Omitting irrigations was not always detrimental if adequate water was available
 in the soil profile to maintain adequate evapotranspiration.   Of major signi-
 ficance was the result that, with few exceptions,  regular application of less
 irrigation water than that required for maximum evapotranspiration produced
 the best water use efficiencies expressed as yield-per-unit of  water consumptively
used.
                                     131

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 78:03F-049
 IRRIGATE—A SCHEDULING MODEL,
 Tscheschke, P.,  Gilley, J.R.,  Thompson,  T.,  and Pischbach,  P.
 Nebraska University,  Lincoln,  Department of  Agricultural Engineering.
 Agricultural Engineering,  Vol.  59,  No.  1, p  45-46,  January, 1978.   1 fig,  4  ref.

 Descriptors:  Water conservation,  Scheduling,  Irrigation, Computer models, Timing,
 Crop production,  Computer  programs, Crop production,  Evapotranspiration,  Climatic
 data, Irrigation systems.

 Irrigation is a  major consumer of  the three  scarce  commodities:   energy,  water,
 fertilizer.  The need for  conservation through good irrigation management prac-
 tices is urgent.   To help  meet these needs,  University of Nebraska has developed
 an irrigation scheduling program called IRRIGATE for its AGNET (Agricultural
 Computer Network)  system.   The network serves  the Institute of Agriculture and
 Natural Resources at the University of Nebraska-Lincoln and benefits the  agri-
 cultural community directly.   As with all AGNET models, IRRIGATE is designed for
 teaching, research and extension work.   Access to AGNET can be made through  small
 portable computer terminals.   These are priced from $2000 and  are about the  size
 and shape of a portable typewriter.  IRRIGATE  records a field's  soil moisture
 status since planting and  answers  the important questions of when and how much
 water should be  applied in future  irrigations.  IRRIGATE 'is designed to be user
 oriented.  IRRIGATE can be used with a wide  variety of irrigation systems, with
 nine commonly grown area crops, with eight common soil types and with a minimum
 of climatic data (maximum  and  minimum temperature only) if necessary.   The irri-
 gation scheduling for about 25,000  acres was handled through IRRIGATE and AGNET
 in 1977.


 78:03P-050
 DRIP IRRIGATION-CHEMICAL,  PHYSICAL  WAYS  TO KEEP EMITTERS OPEN,
 Crops and Soils  Magazine,  Vol.  30,  No.  6, p  15-18,  March, 1978.   9 fig.

 Descriptors:  Maintenance,  Clogging, Irrigation systems, Water conservation,
 Treatment,  Chemical precipitation.

 The most serious  problem in drip irrigation  is plugging of 'emitters caused by
 chemical or biological buildup in minute water passageways. Preventing that
 buildup is a key to successfully operating most drip irrigation  systems.   Re-
 searchers at Yuma and Phoenix,  Arizona approached the clogging problem and
 reclaimed old drip lines by adding  dilute H2SO4 and hypochlorite solution
 (laundry bleach)  to the irrigation  water entering the lines.  After the initial
 "slug" treatment,  the emitters were operating  at 95%  of the designed flow.   After
 the 24- to 36-hour treatment,  the  entire system was treated with lower concen-
 trations of chlorine and acid,  keeping the system at  about 1 ppm chlorine and
 a pH of 7.   That continuous treatment maintained satisfactory  emitter  performance,
 not only in the  older lines but in  a newly installed  system.  More research  is
 being done to expand guidelines for maintaining emitter performance.


 78:03F-051
 LIMITED IRRIGATION TESTS GET RESULTS,
 Irrigation Age Magazine.
 Irrigation Age,  Vol.  12, No. 8, p  72-74, May-June,  1978.  2 fig.

 Descriptors:  Water conservation, Moisture deficit,  Growth stages, Timing, Corn
 (field), Irrigation practices,  Sorghum,  Soybeans, Kansas, Nebraska.

 Limited irrigation experiments were conducted  in Kansas and Nebraska on corn,
 sorghum and soybean.   It was observed by the researchers in the  two states that
 corn yield was reduced by  limiting' irrigation  at any  stage of  growth but  a single
 irrigation was most effective  just  before the  silking stage.  With soybeans, they
 observed that the  most critical period was at  the beginning of pod development,
^whereas with sorghum,  the  timing of irrigation was  not found to  be important
 which gives it a management advantage when using limited water.   The experiments
 showed that the  limited irrigation  techniques  help  in saving water,  energy and
 irrigation equipment,wear  and  tear.
                                     132

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 78:03F-052
 HOW  IDAHO IRRIGATORS TRIM BACK POWER COSTS,
 Henry, C.
 Irrigation Age Magazine.
 Irrigation Age, Vol. 12, No.  8, p  82-84, May-June,  1978.

 Descriptors:  Scheduling, Irrigation,  Irrigation practices/ Electric power costs.
 Fertilizers, Water  conservation, Crop  production, Idaho, Water management  (applied)

 The ibenefits obtained by an Idaho farmer by  irrigation scheduling were reported.
 Irrigation scheduling has not only helped to keep the power cost down but also
 it has reduced labor-hour requirement, leaching of  fertilizers and has resulted
 in increased yields.  One other additional  advantage was in management operations,
 such as thinning  and cultivations, during periods indicated by favorable moisture
 content.


 78:03F-053
 FLOAT VALVES IMPROVE PIPELINE SYSTEMS,
 Humpherys, A.
 Snake River Conservation Research, Agricultural Engineering Division, Kimberly,
 Idaho.
 Irrigation Age, Vol. 12, No.  7, p  12-15, April, 1978.   1 fig, 1 tab.

 Descriptors:  Water conservation,  Floats, Valves, Flow  control, Pipelines, Water
 shortage, Irrigation efficiency.

 Water shortages and rising  energy  and  labor costs are forcing irrigators to look
 for  ways to increase irrigation efficiency and reduce operating costs.  To
 accomplish this,  they need  maximum system flexibility and ease of operation.
 Many  low pressure pipeline  systems can be improved by using float valves to
 provide better and  easier water control.  Float valves  are relatively new and
 since most of them  are used in California where they were developed, many
 farmers are not familiar with them.  This paper discusses the applicability of
 float valves in various situations of field irrigation  systems.


 78:03F-054
 DISTRIBUTION PATTERNS AND LOSSES FOR FURROW IRRIGATION,
 Karmeli, D.
 Colorado State University,  Fort Collins, Department of Agricultural and Chemical
 Engineering.
 Journal of the Irrigation and Drainage Division, American Society of Civil
 Engineers, Vol. 104, No. IR1, p 59-68, March, 197R.  4  fig, 1 fig, 10 ref, 22
 equ,  1 append.

Descriptors:  Furrow irrigation, Surface irrigation, Distribution patterns,
 Irrigation efficiency, Model  studies, Mathematical models, Recession curves,
 Infiltration, Runoff.

A model was developed to describe  the distribution patterns and efficiencies for
 furrow irrigation.  The model consisted of the following:  (1)   A frequency
curve of the diraensionless  infiltration depth (actual infiltered depth/desired
infiltration depth), versus fractional length of run (distance from end of field/
total length of field); (2)    Description of the frequency curve by a mathematical
model that enables the comparison of systems by using the model to establish
the various efficiencies and  other statistical parameters such as the deviation
from  desired application depth.  The model, based on the power curve fit for
surface irrigation systems, was found to be a good representation of actual
patterns of distribution in an irrigated field.  The model suggested allows for
integration of the various  functions related to irrigation performance such as
water-yield function.


78:03F-055
STRAW-MULCH RATE EFFECT ON SOIL WATER STORAGE AND SORGHUM YIELD,
Unger, P.W.
United States Department of Agriculture,  Southwestern Great Plains Research
Center,  Bushland, Texas  79012.
Soil Science Society of America Journal,  Vol.  42,  No.  3, p 486-491, May-June,
1978.  4 fig,  3 tab, 12 ref.
                                     133

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Descriptors:   Mulching, Water conservation, Moisture availability, Grain sorghum,
 Moisture content, Fallowing, Crop response.

 A field study was conducted to determine the effects of straw mulch rates on soil
 water storage during fallow and on subsequent grain sorghum production.  Wheat
 straw at rates of O(check), 1, 2, 4, 8, or 12 metric tons/ha was placed on field
 plots in July 1973, 1974, and 1975.  A different area, previously cropped to dry-
 land wheat, was used each year.  Atrazine (2-chloro-4(ethylamino)-6(isopropylamino)
 -s-triazine) was applied for volunteer wheat and weed control before mulch placement'
 Soil water content was measured periodically from July until the following May,
 when grain sorghum was planted, and during the sorghum growing season.  Available
 soil water at planting averaged 12.3 and 21.4 cm for the 0- and 12-metric tons/ha
 mulch treatments, respectively.  The additional water, along with greater infil-
 tration and lower evaporation during the growing season, increased grain yields,
 which averaged 1,780 and 3,990 kg/ha for the respective treatments.  Water-use
 efficiency increased from 55.6 kg/ha-cm for no mulch to 115.0 kg/ha-cm'for 12
 metric tons mulch/ha.


 78:03F-056
 A SOIL-WATER-NITROGEN MODEL FOR IRRIGATED CORN ON SANDY SOILS,
 Watts, D.G., and Hanks, R.J.
 Nebraska University, Lincoln, Department of Agricultural Engineering.
 Soil Science Society of America Journal, Vol. 42, No. 3, p 492-499, May-June,
 1978.  8 fig,  25 ref,  20 egu, 1 append.

 Descriptors:  Nitrogen, Nitrates, Leaching, Model studies, Soil-water-plant
 relationships, Sweet corn,  Diffusion,  Convection, Water balance, Irrigation.

 A model was developed which describes  the net changes of nitrogen amounts due to
 transformations and the movement, uptake, and loss of nitrogen from the root
 system of irrigated corn (Zea mays L.)  grown on sandy soils.  A potential
 nitrogen uptake function developed from field data is used to determine the
 maximum uptake for nonlimiting soil water and nitrogen availability.   Actual
 uptake is calculated as less than potential when soil water content and/or
 mineral nitrogen concentration and distribution limit convective and diffusive
 movement of nitrate to the  root system.  Separate calculations are made for
 uptake resulting from each  of these two mechanisms.   Seasonal nitrogen uptake
 was  computed within ±15% of measured uptake on field plots where uptake by
 above ground plant material ranged from 105 to 218 kg/ha.   Computed nitrate
 leaching losses compared favorably with losses estimated by multiplying perco-
 lation loss determined from a weekly water balance,  by measured nitrate concen-
 tration at 150 cm depth. Field leaching losses estimated by the water balance-
concentration method ranged  from 37 to  154 kg/ha.


78:03F-057
NITROGEN SOURCES FOR HAY PRODUCTION ON FLOODED MEADOWS,
Ludwick, A.E.,  Rumburg, C.B., and Siemer, E.G.
Colorado State University, Fort Collins, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 3, p 509-512, May-June,  1978.
7 tab, 13 ref.

Descriptors:  Nitrogen, Nitrogen compounds, Ammonium compounds, Fertilizers,
Ureas, Nitrates, Denitrification, Hay,  Flooding, Volatility.

Three experiments were conducted over a 3-year period to compare various urea
materials and ammonium nitrate as N sources for hay production on flooded meadow
sites.  Each experiment was a complete factorial combination of fertilizer N
sources and rates broadcast once in the spring on established forage prior to
flood irrigation.  The N sources in these experiments consisted of ammonium
nitrate, urea,  sulfur-coated urea, urea ammonium polyphosphate and urea ammonium
sulfate.  Hay yields and N uptake were significantly increased by N fertilizer
at each location; there was no significant response in hay yield or N uptake
resulting from residual N in the second season of Experiment 1.  Source of N
did not influence hay yields nor N uptake..  The N content of the hay was signifi-
cantly influenced by the N fertilizer rate at two locations and the N source at
one location.  In general, hay yields and N uptake increased with increasing
rates of fertilizer N.  Fertilizer efficiency was low, at all locations, ranging



                                     134

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between 8.5 and 19.6 kg hay/kg N.  Fertilizer N recovery was <30% for all
treatments.  Both efficiency and recovery of N tended to decrease with increasing
N rates.


78:03F-058
COMPUTER PROGRAMMING SOLID SET SYSTEMS,
Griffin, S.G.
The Toro Company, Riverside, California.
Paper No. 78-2012, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 9 p.

Descriptors:  Sprinkler irrigation, Uniformity coefficient, Computer programs,
Water shortage. Testing, Simulation analysis, Nozzles, Water pressure, Design
criteria, Irrigation efficiency.

Solid set sprinkler system uniformity is of great importance in today's
agriculture.  A computer program for evaluating sprinkler performance has been
developed.  This program has shown to be valuable in product development as well
as providing more accurate information on system operation to the grower in
the field.


78:03F-059
CONTOUR FURROW IRRIGATION WITH LIQUID MANURE USING "MICROTUBING" FOR FLOW CONTROL,
DeTar, W.R.
Pennsylvania State University, University Park, Department of Agricultural
Engineering.
Paper No. 78-2027, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 45 p.  15 fig, 9 tab,
4 ref, 78 equ.

Descriptors:  Contour furrows, Furrow irrigation, Fertilizers, Liquid wastes,
Flow control, Irrigation systems, Irrigation, Water management (applied).

The trickle-furrow concept is introduced.  The low infiltration rate of dilute
liquid manure makes possible 100 ft lengths of run with only 0.3 gpm/furrow.
Furrows can run 8 hrs/set.  Proposed is a solid-set arrangement of 1000 ft of
corrugated plastic tubing laterals descending 5-10% slopes with microtubing
outlets at each furrow.  Field experiment yields rate-of-advance curves.  A
prediction equation is given for length of run.  Friction loss data are
presented.  Work is still in progress.


78:03F-060
MANAGEMENT FOR MINIMIZING NITROGEN LEACHING LOSSES ON IRRIGATED SANDY SOILS,
Watts, D., Martin, D., Tscheschke, P., and England, M.
Nebraska University, Lincoln, Department of Agricultural Engineering.
Paper No. 78-2025, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 22 p.  14 fig, 8 ref.

Descriptors:  Nutrient removal, Nitrogen, Nitrates, Leaching, Organic matter,
Water management (applied), Nitrogen fixation, Corn (field), Nebraska, Soil
texture.

A model study was made to evaluate nitrogen uptake and the loss of water and
nitrate from the root zone of irrigated corn on sandy soils in Western Nebraska.
Three N sources, two N amounts and a wide range of irrigation applications were
simulated for growing seasons with normal and 75 percent above normal rainfall.
Control of irrigation amounts to minimize percolation and proper selection of
nitrogen amount and source all had a significant effect on nitrate leaching loss.
                                     135

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 78:03F-061
 PEACH TREE  RESPONSE TO DRIP APPLICATION OF WATER AND NUTRIENTS,
 Chesness, J.L., and Couvillon, G.A.
 Georgia University, Athens, Department of Agricultural Engineering.
 Paper No. 78-2019, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 19 p.  1 fig, 4
 tab, 36 ref.

 Descriptors:  Irrigation systems, Crop response, Crop production, Peaches, Water
 management  (applied), Fertilization, Nutrients, Nutrient requirements, Irrigation,
 Southeast United States.

 Two years of peach tree response to drip irrigation were reported on.  Four
 treatments  involving two water regimens and two water applied fertilizer rates
 were investigated.  Yield in kg/cm trunk diameter/tree averaged 43 percent
 higher for  the irrigated treatments.  There was no significant differences in
 the yield and elemental leaf tissue levels for trees receiving one-half levels
 of nutrients applied through the system.


 78:03F-062
 QUANTIFICATION OF RICE YIELD BENEFITS ATTRIBUTABLE TO IRRIGATION WATER,
 Bhuiyan, S.I., and Sumayao, A.
 International Rice Research Institute, Los Banos, Laguna, Philippines,
 Department  of Irrigation and Water Management.
 Paper No. 78-2022, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 12 p.  15 fig, 1 tab,
 16 ref.

 Descriptors:  Rice, Irrigation, Water management (applied), Moisture stress,
 Crop response, Crop production, Yield equations/ Regression analysis, Management,
 Irrigation  effects.

 An experiment with a split-plot design was conducted at three different locations
 to grow LR-36 variety of rice in the dry season when no crop can be grown without
 irrigation water in order to quantify rice yield benefits due to irrigation under
 farmers' field condition.  Five irrigation treatments, representing various
 degrees of water stress during the reproductive growth stage of the crop, were
 imposed in  the main plots and three management package treatments, representing
 the average farmer's level, intermediate level and high level use of other
 inputs, were imposed in the subplots.  High level of management combined with
 adequate water produced about 5.1 t/ha, whereas farmer level management under
 adequate water yielded 2.9 t/ha.  Yield was reduced consistently as stress days
 increased.  An average of thirty one stress days caused a yield reduction of
 1.0 t/ha under the farmer level, management, but an average reduction of about
 1.5 t/ha under the two higher level managements.  A regression model developed
 showed that the location of the experiment had no significant effect on the
yield.  The model predicts yield variation due to stress days and level of
management.  Management was found to have a much stronger influence on yield
 than water  stress.


 78:03F-063
POTATO AND LETTUCE RESPONSE TO IRRIGATION METHODS AND PRACTICES,
Sammis, T.W., and Hanson, E.G.
New Mexico State University, Las Cruces.
Paper No. 78-2020, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 11 p.  2 fig, 7 tab,
 9 ref.

Descriptors: Irrigation practices, Irrigation systems. Surface irrigation,
Subsurface irrigation. Sprinkler irrigation, Potatoes, Lettuce, Irrigation
efficiency, Crop response, Crop production.

Spring potatoes and fall lettuce were irrigated with sprinkler, trickle, sub-
surface, and furrow irrigations for two consecutive years.   Results are pre-
sented that pertain to the influence of these methods on crop yield,  water-use
efficiency, quality at maturity, and the variability of measurements.  The lowest
irrigation ratio for two consecutive years was achieved by trickle and subsurface.


                                     136

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 Water-use efficiency was  indeterminate  for  the  1975  lettuce  cropping year.   In
 1976,  lettuce that was  subsurface  irrigated resulted in  the  highest water-use
 efficiency.   Potatoes subsurface and trickle irrigated resulted  in the highest
 water-use efficiency in 1975,  and  those irrigated  by subsurface  irrigation
 resulted in  the  highest water-use  efficiency in 1976.


 78:03F-064
 ASSESSING TRICKLE  EMITTER APPLICATION UNIFORMITY,
 Nakayama,  F.S.,  Bucks,  D.A., and Clemmens,  A.J.
 U.S. Water Conservation Laboratory,  4331 East Broadway,  Phoenix, Arizona  85040.
 Paper  No.  78-2017, Presented at the  1978 Summer Meeting  of the American Society
 of  Agricultural  Engineers, June 27-30,  1978,  Logan,  Utah, 7  p.   6 fig, 2 tab,
 4 ref,  14  equ, 2 append.

 Descriptors:   Irrigation  systems,  Uniformity  coefficient, Water  conservation,
 Application methods,  Irrigation efficiency,  Sprinkler irrigation, Statistical
 methods,  Flow rates,  Frequency curves,  Irrigation.

 A method was  developed  for showing the  uniformity  of water application by trickle
 emitters based on  the emitter's coefficient of  variation.  The derived design
 uniformity coefficient  equation for  different numbers of emitters per plant
 was related to the uniformity  coefficient used  in  sprinkler  irrigation.  The
 interrelationship between the  computed  design uniformity coefficient, the
 manufacturer's coefficient of  variation for the  emitter, and the number of
 emitters per  plant can  be used as  a  guide for selecting  the  number of emitters
 per plant.  In addition,  a field uniformity coefficient and  a field emitter
 coefficient of variation  were  related to the  fraction of plants  adequately
 irrigated.


 78:03F-065
 DRIP IRRIGATION  OF ORANGE TREES IN HUMID CLIMATE,
 Myers,  J.M.,  and Harrison, D.S.
 Florida University,  Gainesville, Department of Agricultural  Engineering.
 Paper  No.  78-2018, Presented at the  1978 Summer  Meeting of the American Society
 of Agricultural  Engineers, June 27-30,  1978,  Logan,  Utah, 7  p. .  9 tab, 8 ref.

 Descriptors:   Sprinkler irrigation,  Irrigation systems, Oranges, Humid climates,
 Fertilization, Citrus fruits.  Crop production, Irrigation, Statistical methods,
 Florida.

 Results of a  four-year  study of drip and overhead sprinkler  irrigation on orange
 trees grown in Florida  on a sandy  soil  indicate  responses are highly dependent on
 rainfall amounts and characteristics.   For a  year with rainfall 28% below normal
 average yields from  trees with 2,  4 and  6 emitters/tree were 4.00, 4.24 and 4.83
 boxes/tree, respectively.   Yields  for sprinkler  and no irrigation checks were
 4.41 and 2.37 boxes/tree.   Differences  In yield  between the  three drip irrigation
 treatments and the sprinkler check were not significant at the 95% confidence
 level, however,  all  four  of these  treatments were significantly better than the
 no irrigation  check.  Average yields for quantities of water for drip irrigation
were 4.13, 5.16  and  5.43  boxes/tree for low medium and high amounts,  respectively.
 The statistical  significance of the water quantity results are identical to those
 for the emitter  density results.  Supplemental fertilizer application,  through
 the drip water distribution system, of  19-0-19 k/ha/year and 38-0-38 k/ha/year
 of N-P-K did not appear to influence yields of oranges.  Irrigation treatments
 did not significantly affect production in years with average or above average
 rainfall.  Juice content  and quality was not  influenced by irrigation treatment
 or rainfall.


 78:03F-066
A SOLAR-POWERED  PUMP FOR  IRRIGATION,
Alexander, G.H.
Battelle Memorial Institute, Columbus, Ohio, Columbus: Laboratories.
Proceedings of The Irrigation Association,  Stouffer's Towers, Cincinnati,  Ohio,
p 1-19, February 26-28,  1978.   8 fig.

Descriptors:   Pumps,  Pumping plants,  Irrigation, Energy conversion,  Economic
feasibility.

                                     137

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 A solar-powered irrigation pump designed for the Northwestern Mutual Life
 Insurance Company by Battelle Memorial Institute has been in experimental and
 developmental operation at Northwestern Mutual's Paloma Ranch near Gila Bend,
 Arizona, since April 1977.  An objective of this program was to design and
 construct a prototype 35- to 50-horsepower solar-energy pumping system to
 evaluate its applicability in a working irrigation environment.  The range
 includes approximately 22,000 irrigated acres; the yearly energy bill for
 pumping water is approximately $1.5 million.


 78:03F-067
 ENERGY AND IRRIGATION,
 Oostermeyer,  J.S.
 Shell Chemical Company,  Houston,  Texas.
 Proceedings  of The Irrigation Association,  Stouffer's  Towers,  Cincinnati,  Ohio,
 p  20-27, February  26-28,  1978.

 Descriptors:   Energy, Energy  conversion,  Irrigation, Agriculture,  Irrigation
 practices, Pesticides, Fertilizers,  Nuclear energy,  Oil,  Natural gas.

 This  paper reviews the energy situation  in  the United  States  and how the  energy
 shortage is  going  to affect the national  economy,  thereby,  the irrigated
 agriculture.   It also suggests  the  directions  of a sound  national  energy  policy
 to deal with  the situation and  recommends better farm  management practices to
 reduce the cost  of energy in  irrigated agriculture.


 78:03F-068
 SOLID STATE  CONTROL SYSTEMS FOR IRRIGATION,
 Marian,  M.B.
 Solar Wind Systems,  Incorporated, San  Rafael,  California.
 Proceedings of The Irrigation Association,  Stouffer's  Towers,  Cincinnati, Ohio,
 p 35-37,  February  26-28,  1978.

 Descriptors:   Irrigation  programs,  Irrigation, Scheduling,  Control  systems,
 Automatic control.  Computer programs,  Computer models.

 This  paper discusses  the  basic  principles of solid state  control systems, causes
 of failure or  malfunction of  the systems, customer's responsibilities to insure
 proper function, and  their applicabilities  in  irrigation  scheduling.  Further,
 it discusses  three basic  ways to program an irrigation controller and recommends
 the use  of removable media such as programming with a mark  sense card.


 78:03F-069
 ELECTRICAL LOAD AND WATER MANAGEMENT,
 Heermann, D.F., and Duke,  H.R.
 Science  and Education Administration, Fort Collins, Colorado, United States
 Department of  Agriculture.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p 60-67,  February  26-28,  1978.  4 fig, 9 ref.

 Descriptors:   Load distribution. Electric power demand, Water management  (applied)*
 Peak  loads, Sprinkler irrigation.

 The objective of this paper is first, to review the presently used techniques
 for retducing peak demands on electrical systems,  second, to examine a technique
 for improving  the water management of center pivot sprinkler systems and, third,
 to explore the integration of load management and water management.  An analysis
 of these  aspects led to the conclusion that an integrated load and water manage-
ment  control system offers significant cost savings to today's irrigator.


 78.-03F-070
CENTER PIVOTS ON SOILS MARGINALLY SUITED FOR IRRIGATION IN MANITOBA, CANADA,
Penkava, F.F.
Manitoba University, Winnipeg, Manitoba, Canada,  Department of Agricultural
Engineering.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati,  Ohio>
p 68-75, February 26-28,  1978.  3 fig,  7 ref.

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 Descriptors:  Sprinkler irrigation, Irrigation effects, Soil classification,
 Productivity, Crop production, Soil erosion, Runoff, Potatoes, Soil physical
 properties, Canada.

 The Almasippi series soils of Manitoba have poor moisture holding capacity and
 high groundwater tables.  In spite of those very serious disadvantages irrigated
 potato production will likely expand on the Almasippi soils.  In order to acquire
 more knowledge on the proper use of center pivot irrigation and on the possible
 problems and measures for their elimination, a research project was initiated
 in the spring of 1977 on two localities on which center pivot units were just
 being installed.  The following preliminary conclusions were made based on the
 research findings:   (1) Center pivots, or any other irrigation systems used on
 the Almasippi series soils in Manitoba must be carefully designed and operated;
 (2)  Single applications should not exceed 20 mm;  (3)  Application intensities
 must be carefully balanced with infiltration capacities of the soils and no
 credit must be given to surface water detention; (4)  In carbonated areas applica-
 tion intensity should not exceed 5 mm per hour (0.2 inch/hr); (5)  Oversized
 center pivot units with high precipitation intensities near the end tower should
 not be used; (6) Random subsurface drainage should be used to control the
 groundwater levels in the depressions; and (7)  Research should continue under
 real irrigation conditions.


 78:03F-071
 APPLICATION OF END GUNS ON CENTER PIVOTS,
 Hanson, R.E.
 Nelson Irrigation Corporation, Grand Island, Nebraska.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p 91-103, February 26-28, 1978.   8 fig.

 Descriptors:  Sprinkler irrigation, Uniformity coefficient, Distribution patterns,
 Drops (fluids),  Application equipment. Crop production. Water management (applied),

 The main factors probably considered by the pivot irrigator in selecting the use
 of end guns are the favorable cost per acre and obtaining the maximum corner
 coverage.  Use of end guns in combination with corner covering type systems, end
 gun :sizes in combination and larger end guns have been more recent adaptations
 on center pivots to extend the corner coverage.  Many factors affect the corner
 coverage obtainable with an end gun.  Some of these factors can only be determined
 through a complete system design for the conditions.   Selection of the end gun
 for the system conditions are based primarily on the gun performance, arc setting,
 pressure, trajectory angle and nozzle size.  Proper application of end guns
 generally involves the same field, soil, crop,  climatic and water  supply condi-
 tions that must be considered in center pivot application.   In addition to ob-
 taining maximum effective corner coverage, other considerations are uniformity
 of application,  droplet impact conditions and application rate.  This paper
 discusses the factors affecting these considerations in the use of end guns on
 center pivot systems.


 78:03F-072
 LIMITS OF LOW PRESSURE SPRINKLERS AND SPRAY NOZZLES ON  CENTER PIVOT APPLICATIONS,
 Gilley,  J.R.
 Nebraska University,  Lincoln, Department of Agricultural Engineering.
 Proceedings of The Irrigation Association, Stouffer's Towers,  Cincinnati, Ohio,
 p 104-115, February 26-28, 1978.   6 fig, 3 tab, 9 ref,  1 equ.

 Descriptors:  Sprinkler irrigation, Limiting factors, Nozzles,  Application
 equipment, Uniformity coefficient, Pressure head, Irrigation efficiency,  Runoff,
 Soil erosion.

Low pressure center pivot irrigation systems offer the potential of applying
irrigation water with significant energy savings.  However,  lowering the pressure
of center pivot systems may create potential problems of runoff and soil erosion,
uniformity of water application and operation.  The future use of low pressure
systems is dependent upon the solutions of these problems.  In some cases low
pressure systems should not be used.  This paper presents an analysis and
discussion of the effects of lower pressures on center pivot applications.



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 78:03F-073
 SCHEDULING OF WATER AND NITROGEN FOR CORN IN THE HUMID MIDWEST,
 Vitosh, M.L.
 Michigan State University, East Lansing, Crop and Soil Science Department.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p  116-123, February 26-28, 1978.  1 fig, 4 tab, 11 ref.

 Descriptors:  Scheduling, Irrigation, Water management (applied), Sweet corn,
 Nitrogen, Fertilization, Humid climates, Michigan.

 This study was conducted in Michigan on irrigated sandy soils where irrigation
 of corn is a relatively new practice compared to the semi-arid regions.  It was
 recommended that application rate should not exceed 30% of the water holding
 capacity in the effective rooting zone since the optimum soil moisture level
 for corn is usually between 50 and 80% of the available water holding capacity.
 This will prevent or minimize the leaching of nitrate-nitrogen from the rooting
 zone in the event of rain.  Adequate moisture must be available at the end of the
 growing season to carry the crop to maturity.  Further, it was recommended to
 apply approximately one-third of the total N requirement for the crop as:  (a)
 preplant incorporated or pre-emergence with a herbicide;  (b) one-third sidedress
 or pre-emergence if the first third was applied preplant; and (c) one-third through
 the irrigation system which should be applied prior to pollination.


 78:03F-074
 THE ROLE OF SPRINKLER IRRIGATION IN PRODUCING SPECIALTY CROPS,
 Patterson, C.
 Patterson Farms, China Grove, North Carolina.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p 124-125, February 26-28, 1978.

 Descriptors:  Sprinkler irrigation, Frost protection, Freezing, Tomatoes,
 Strawberries, North Carolina.

 The benefits of using a solid set sprinkler irrigation system for frost and freeze
 protection of tomato and strawberry production in North Carolina were discussed.


 78:03F-075
 THE USE OF OVERTREE IRRIGATION FOR CROP COOLING AND FROST AND FREEZE PROTECTION
 ON APPLES,
 Unrath,- C.R., and Sneed, R.E.
 North Carolina State University, Raleigh, Department of Horticultural Science.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p 131-134, February 26-28, 1978.

 Descriptors:  Sprinkler irrigation, Cooling, Freezing, Frost protection, Apples,
 Peaches, Fruit crops,  North Carolina.

 Overtree irrigation for apple orchard cooling has proven to be an effective method
 of microclimate modification resulting in markedly improved fruit quality and
 greater grower returns.  The experimental results showed that the evaporative
 cooling resulted in increased fruit coloration of red varieties' apples and in-
 creased sugar content, fruit size and reduced incidence of cork spot and bitter
pit.  The application rates of 0.16 in/hr to 0.18 in/hr were found to be effective
 and to provide higher water use efficiency than lower application rates.  Over-
 tree irrigation for frost and freeze protection was also evaluated and application
 rate between 0.16 in/hr to O.18 in/hr was recommended for severity of freeze
 conditions.


 78:03F-076
OPTIMIZING TRAVELING SPRINKLER SYSTEM PERFORMANCE,
 Rupar,  B.
Nelson Irrigation Corporation, Walla Walla, Washington.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 152-159, February 26-28, 1978.  5 fig,  1 tab, 2 equ.
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Descriptors:  Sprinkler  irrigation, Uniformity coefficient, Application equipment,
Pressure head, Distribution pattern, wind velocity.

Many  factors affect the  proper performance of traveling sprinkler irrigation
systems.  Among  the most important considerations are uniformity of application,
water droplet conditions and the application rate of the system.  Test data, as
well  as actual field experience, confirms that a high degree of uniformity is
achievable with  a traveler, as long as proper lane spacing arid travel direction
are utilized, as well as proper arc setting the pressure.  Acceptable droplet
conditions can be achieved only through the use of adequate pressure and proper
selection of trajectory  angle for a given nozzle size.  Application rates for
travelers are sufficiently low to make them adaptable for most soil conditions.


78:03F-077
INTRODUCTION TO  IRRIGATION EFFICIENCY AND SCHEDULING,
Aljibury, F.K.
California University, Parlier, Cooperative Extension.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 160-161, February 26-28, 1978.  1 tab.

Descriptors:  Irrigation efficiency, Scheduling, Water shortage, Sprinkler
irrigation, Consumptive  use, Agriculture.

The subject of rational  use of water is of vital interest.  The allocation of
existing supplies of water is becoming difficult and controversial.  Irrigation
efficiency and scheduling concepts play important roles in this context.


78:03F-078
FACTORS INFLUENCING SYSTEM SELECTION IN HUMID REGIONS,
Curtis, L.M.
Auburn University, Auburn, Alabama, Alabama Cooperative Extension Service.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 126-130, February 26-28, 1978.  5 fig.

Descriptors:  Irrigation, Humid areas. Humid climates. Southeast United States,
Irrigation systems, Sprinkler irrigation.

Factors and difficulties that should be evaluated in considering cable tow and
center pivot irrigation  systems of 'farms in the Southeast United States were
discussed.  The  following factors have been analyzed:  (1) water supply; (2)
topography and surface characteristics; (3)  crops grown and rotation schemes;
and (4) economic considerations.  It was concluded that the factors influencing
system selection in the  Southeast are numerous.   The less favorable factors
may slow or prohibit development of irrigation in some areas.  However, continued
expansion of irrigated cropland appears likely as farmers incorporate irrigation
as a production or management tool in their overall farming operation.


78:03F-079
SOCIETAL ATTITUDES AND RESULTANT POLICIES CALL FOR WATER CONSERVATION,
Hagan, R.M.
California University, Davis, Department of Land, Air and Water Resources.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 162-179, February 26-28, 1978.

Descriptors:  Water conservation,  Social aspects, Social impact, Social
participation, Water policy, Agriculture, Irrigation practices. Irrigation
efficiency,  Evapotranspiration, California.

The water situation and, to some extent, societal attitudes have changed
dramatically in California within the past few months.  This paper briefly touches
on a number of aspects in order to provide a sample of the kinds of thoughts
being expressed about irrigation agriculture, especially by environmental
leaders.  Several points are covered in some detail.   Hopefully, these comments
will provide a useful indication of what some vocal elements in today's society
are saying which bear on agricultural water conservation and on the irrigation
industry.


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 78:03F-080
 WATER EFFICIENCY WITH DEFICIT AND SUBOPTIMAL  IRRIGATION,
 Aljibury, F.K./ Gerdts, M., and Beutel, J.
 California  University, Parlier, Cooperative Extension.
 Proceedings of The  Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p  180-182,  February 26-28, 1978.  3 tab.

 Descriptors:  Cultural control, Water shortage, Water conservation, Irrigation,
 Furrow irrigation,  Fruit crops, Water management  (applied), Irrigation systems,
 Irrigation  efficiency, California.

 Irrigation  is considered one of the most important cultural practices in the arid
 and semi-arid irrigated areas of the world.   The  increasing demand for water and
 its limited supplies requires maximum efficiency  in its use for irrigation.  To
 achieve this end, many water specialists and  plant scientists have been conducting
 studies to  determine the effect of deficit irrigation on the production "of food
 and fibrous crops.  The objectives of such experiments are to maximize production
 under  conditions of drought or limited water  supplies.  The authors concluded
 from  their  experimental results that the effect of deficit irrigation by furrow
 irrigation  on the early growth of the plum trees was not significant.  The
 deficit irrigation  did not cause unusual leaf abscission or premature fruit drop.
 Total  production was not affected but water savings was significant.  The effect
 of deficit water treatments in the drip irrigated plots, on the soil water
 potential and deep moisture extraction was found  to be very evident.  These
 irrigations did not effect the number of fruits per tree and bud initiation of
 future seasons significantly but produced fruits of smaller size.


 78:03F-081
 COMPARATIVE EFFICIENCY OF IRRIGATION SYSTEMS,
 Shearer, M.N.
 Oregon State University, Corvallis.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p 183-188, February 26-28, 1978.  4 fig, 2 tab.

 Descriptors:  Irrigation efficiency, Irrigation systems, Uniformity coefficient,
 Sprinkler irrigation, Surface irrigation, Seepage, Runoff, Evaporation.

 The purpose of this paper is to compare efficiencies obtainable with various
 irrigation systems having reasonably good designs.  Also, several concepts of
 field  irrigation efficiency have been discussed.


 78:03F-082
 IRRIGATION EFFICIENCY IN SCHEDULING,
 Tribe, G.
 Cornell Pump Company, Portland, Oregon.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
 p 189-191, February 26-28, 1978.

 Descriptors:  Pumps, Pumping plants, Pump testing, Efficiencies, Design criteria.

 Testing and experimentation have proven that a pump's ability to convert rotating
 kinetic energy to hydraulic pressure energy is predictable.  This energy conversion
 efficiency can be improved by the application of proven engineering fundamentals.
 This paper discusses the need for improving pump efficiency and the factors which
must be considered for improved pump design and to reduce the cost of ownership.


 78s03F-083
AUTOMATION OF SURFACE IRRIGATION,
Eisenhauer,  D.E.,  and Fischbach, P.E.
Nebraska University, Clay Center,  South Central Station.
 Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 196-205, February 26-28, 1978.  1 fig, 4 tab, 7 ref.

 Descriptors:  Surface irrigation,  Automation control,  Irrigation efficiency,
 Irrigation systems,  Cost comparisons,  Nebraska.
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 Efficient and low labor irrigation systems  appear  to be  the way of  the future.
 Automation of conventional  gated  pipe  systems  is a good  way of improving
 efficiency and yet holding  down labor  requirements.  The main additional com-
 ponent of the automatic system is the  automatic valve.   One such valve is on
 the  market now and another  will be available soon.  Design of automatic systems
 involves  properly sizing pipeline and  other components,  using normal engineering
 criteria, plus designing for  the  proper  field  length and furrow stream size.
 Annual costs  of automatic gated pipe is  higher than conventional gated pipe
 systems,  but  recent trends  in automatic  sprinkler  systems suggest that farmers
 are  willing to invest  the extra capital  to  reduce  labor  demands.


 78:03F-084
 PRACTICAL SURFACE IRRIGATION,
 Gosling,  R.
 West Side Pump Company,  Dos Palos,  California.
 Proceedings of The Irrigation Association,  Stouffer's Towers, Cincinnati, Ohio,
 p  206-208,  February 26-28,  1978.

 Descriptors:   Surface  irrigation,  Sprinkler irrigation,  Irrigation  systems,
 Automation, Cost  comparisons,  Flexibility,  California.

 This paper discusses and makes a  comparative analysis of gated pipe surface
 irrigation systems with respect to other systems.


 78:03F-085
 MEASURING EFFICIENCY OF SURFACE IRRIGATION  SYSTEMS,
 Robinson,  S.C.
 Bennett & Bennett Irrigation  Pipe  Company,  Hanford, California.
 Proceedings of The Irrigation Association,  Stouffer's Towers, Cincinnati, Ohio,
 p  209-212, February 26-28,  1978.

 Descriptors:   Surface  irrigation,  Irrigation efficiency, Application methods,
 Application equipment,  Return flow, Irrigation systems,  Measurement, Border
 irrigation, Furrow irrigation, Sprinkler irrigation.

 The  reasons behind the  concept of  irrigation efficiency, the definition of
 application efficiency,  and the various  components of efficiency measurement of
 surface irrigation systems  were discussed.  Moreover, the rules of thumb were
 outlined  which could be  used  in field  applications to attain high application
 efficiency of  surface  irrigation systems.


 78:03F-086
 SOLAR  CELL IRRIGATION,
 Fischbach, P.E.,  and Matlin,  R.W.
 Nebraska  University, Lincoln, Department of Agricultural Engineering.
 Proceedings of  The  Irrigation Association,  Stouffer's Towers, Cincinnati, Ohio,
 P  213-217, February 26-28,  1978.    1 fig, 2  tab.

 Descriptors:   Irrigation, Energy,  Energy conversion, Irrigation systems,  Surface
 irrigation, Automation,  Computer programs,  Irrigation programs, Nebraska,
 Application equipment.

 In the first project of  its kind,  the  largest solar cell-powered crop irrigation
 system on earth has been constructed on  the University of Nebraska field
 laboratory in Mead, Nebraska.  Success of the experimental irrigation system could
 demonstrate an  alternate source of energy for irrigation.  A discussion about the
 photovoltaic solar  cells used in the project,  how they converted the solar energy
 to electrical energy and how the 80 acre-irrigation project was run and managed
 by the system were discussed.


 78:03F-087
EVALUATION CRITERIA FOR TRICKLE IRRIGATION EMISSION DEVICES,
Solomon, K.
 Rain Bird Technical Services, Logan, Utah.
Proceedings of The Irrigation Association,  Stouffer's Towers,  Cincinnati,  Ohio,
p 218-225, February 26-28,  1978.   4 ref.

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Descriptors:  Irrigation, Irrigation systems, Trickling filters, Clogging, Pressure
head, Variability, Costs, Risks.

The emission device is sometimes referred to as the heart of a trickle irrigation
system.  It is important to compare carefully the different types of emission
devices available in order to choose wisely from among possible alternatives.
This paper suggested and discussed some of the factors to be considered when
judging and comparing emission devices.  The author suggested that the following
seven fundamental factors should be examined to select a particular emission
device to use in a system:  (1) General suitability;  (2) Pressure-flow relation-
ships; (3) Manufacturing variability;  (4) Flow rate sensitivity to water tempera-
ture; (5) Sensitivity to clogging; (6) Cost and (7) Risk.  Some of these can be
considered engineering performance factors, and hence can be measured and
evaluated only subjectively.


78:03F-088
TRICKLE DESIGN FOR MIDWEST CONDITIONS,
Gamble, J.
Farm Bureau Services, Incorporated, Hart, Michigan.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 226-230, February 26-28, 1978.

Descriptors:  Irrigation, Irrigation systems, Irrigation design, Irrigation
operation and maintenance, Clogging, Pipelines, Water shortage, Water conservation.

This paper discussed trickle irrigation design concepts, water resources used
for this system in the midwest United States, and installation and operation
criteria for such a system.  Current problems facing the users and/or the
installer of the system were also discussed.


78:03F-089
TRICKLE IRRIGATION IN HUMID ZONES,
Braud, H.J.
Louisiana State University, Baton Rouge, Departmen-t of Agricultural Engineering.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 231-238, February 26-28, 1978.  2 fig, 2 tab, 6 ref.

Descriptors:  Irrigation systems, Irrigation, Irrigation design, Humid areas,
Louisiana, Productivity, Citrus fruits. Sugarcane.

The need for irrigation in a humid area is specific to the particular crop-soil-
climate.   Not all crops respond to irrigation:  Citrus does, but not sugarcane
in Louisiana.  Work group meetings of scientists interested or involved in
trickle irrigation were held last year to define the most important problems of
trickle irrigation.  A regional research project draft was written, "Trickle
Irrigation in Humid Regions," with the following objectives:  1) To determine
water requirements and water management techniques; 2). To develop best procedures
for applying N, P and K; 3)  To determine causes of clogging in humid regions and
develop methods to minimize it; 4) To optimize crop management practices; 5) To
examine water and nutrient flow patterns and related root development; 6) To
examine the costs, returns and profitability of trickle irrigation.  Research on
trickle is underway or planned at 17 state agricultural experiment stations and
United States Department of Agriculture, Agricultural Research Service research
stations in Louisiana.


78:03F-090
BACTERIAL CLOGGING IN LOW PRESSURE IRRIGATION SYSTEMS,
Ford, H.W.
Florida University, Lake Alfred, Institute of Food and Agricultural Sciences.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 239-244, February 26-28, 1978.  2 fig, 7 ref.

Descriptors:  Irrigation systems, Low-flow augmentation, Clogging, Irrigation,
Bacteria, Slime.
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Bacterial slimes are the fundamental cause of most clogging problems.  There are
no types of low pressure irrigation systems immune to slime clogging.  Chlorine,
when used in combination with suitable filtration, will control most of the
slimes and associated agents that clog irrigation emitters.  Chlorine, like
other pesticides, requires a special use label in order to be used in drip
irrigation systems.


78:03F-091
IA SPRINKLER TEST STANDARDS,
Bruce, D.A.
Product Design & Systems Engineering, Ag-Turf Division, Johns-Manville Sales
Corporation, Fresno, California.
Proceedings of The Irrigation Association, Stouffer's Towers, Cincinnati, Ohio,
p 282-289, February 26-28, 1978.  2 tab.

Descriptors:  Sprinkler irrigation, Testing procedures. Standards, Testing,
Performance, Irrigation, Evaluation.

After many years of discussion, rejection and frustration, the irrigation industry
is on the threshold of adopting a uniform method of testing sprinklers, collecting
test data and reporting product performance.  This paper outlives the sprinkler
test procedure developed by a working committee formed by The Irrigation
Association.  The IA is attempting to issue a joint standard with the American
Society of Agricultural Engineers.


78:03F-092
A NOTE ON THE ECONOMIC SIGNIFICANCE OF UNIFORM WATER APPLICATION,
Seginer, I.
Technion, Haifa, Israel, Department of Agricultural Engineering.
Irrigation Science, Vol. 1, No. 1, August, 1978, p 19-25.  3 fig, 7 ref, 23 equ.

Descriptors:  Water distribution  (applied), Crop production, Water costs,
Optimization, Economics, Distribution patterns, Sprinkler irrigation, Yield
equations.

It was shown how a yield vs water application diagram, with uniformity of water-
distribution and price of water as parameters, can be used to determine the
optimum water application and the expected income for a certain crop.  The
diagram can further be used to explore the possible outcome of changing water
uniformity and/or price.  The diagram was based on simplified forms of the
yield and water-distribution functions.


78:03F-093
ANALYSIS OF TRICKLE IRRIGATION WITH APPLICATION TO DESIGN PROBLEMS,
Bresler, E.
Institute of Soils and Water, Agricultural Research Organization, The Volcani
Center, Bet Dagan, Israel, Division of Soil Physics.
Irrigation Science, Vol. 1, No. 1, August, 1978, p 3-17.  6 fig, 1 tab, 18 ref,
19 equ.

Descriptors:  Irrigation design, Water conservation, Design, Flow rates,
Infiltration, Hydraulic conductivity, Unsaturated flow.

An existing numerical solution to nonsteady state infiltration was used to
quantify the effect of soil hydraulic properties and trickle discharge rates
on emitter spacing.  The results of the analysis suggested the possibility of
controlling the wetted volume of a soil by regulating the emitter discharge
according to soil properties.  The surface distribution of a transformed soil
water content (or pressure) function was derived from a linearized solution
to steady infiltration.  The analysis of steady and nonsteady infiltration
was employed to estimate the spacing between emitters as a function of discharge
and water pressure conditions between emitters using hydraulic soil data.
Hydraulic conductivity parameters were given for 17 different soils which were
used for design purposes.  Theoretical analysis of soil water was combined with
hydraulic principles to derive lateral diameter and length for engineering
design requirements.


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 78:03F-094
 CENTER PIVOT IRRIGATION IN THE COLUMBIA BASIN OF WASHINGTON AND OREGON:   DYNAMICS
 AND IMPLICATIONS,
 Muckleston,  K.W.,  and Highsmith,  R.M.
 Oregon State University,  Corvallis,  Department of Geography.
 Water Resources Bulletin,  Vol. 14,  No.  5,  p 1121-1128,  October, 1978.   1 fig,
 13 ref.
(See 78:06A-007)


 78:03F-095
 METHODOLOGY  AND EMPIRICAL  ESTIMATES  OF  THE RESPONSE  FUNCTION OF SORGHUM  TO  IRRIGATION
 AND SOIL MOISTURE,
 Bielorai,  H.,  and  Yaron, D.
 Institute of Soils  and Water,  The Volcani  Center,  Bet-Dagan, Israel, Institute  of
 Agricultural Research.
 Water Resources  Bulletin,  Vol.  14, No.  4,  p 966-977, August, 1978.   3  tab,  4 fig,
 17 ref.

 Descriptors:  *Methodology,  *Irrigation, *Soil moisture,  *Sorghum,  *Crop response,
 Estimating,  Equations,  Systems analysis, Response  function,  Critical days.

 Presented is a methodology for the estimation of response functions of crops to
 irrigation and soil moisture.   A  systems analysis  framework  is  applied to describe
 the relationships  involved.  Two  subsystems are distinguished,  with the  first one
 involving  the  relationship between irrigation decision  variables and soil state
 variables, and the  second  involving  the relation between  soil state variables and
 crop yield.  A method for  tracing and predicting soil moisture  profile variations
 over time  and  depth is presented, and empirical estimates of the response function
 of grain sorghum to soil moisture are derived.   In the  specification of  the response
 function the concept  of "critical days" is applied with a "critical day"  being
 defined  as one where  the soil  moisture  is  depleted below  a certain critical level.
 The paper  provides  empirical evidence for  the usefulness  of  the approach.


 78:03F-096
 ECONOMIC AND AGRONOMIC EFFECTS  OF HIGH  IRRIGATION  LEVELS  ON  ALFALFA AND  BARLEY,
 Delaney,  R.H., Jacobs,  J.J., Borrelli,  J.,  Clark,  R.T., and  Hedstrom, W.E.
 Wyoming  University, Laramie, Water Resources  Research Institute.
 Water Resources  Series  No.  68,  January, 1978,  78 p.  7  fig,  27  tab, 46 ref.

 Descriptors:   Irrigation  effects, *Agronomic crops, *Drainage, *Agricultural
 econcwd.cs, *Irrigation practices, Income,  Labor savings,  Profit, Surface
 irrigation,  Crop response,  Irrigation efficiency,  Leaching,  Water injury,
 Alfalfa, Barley, Feed barley,  Malt barley,  Overirrigation, Excess water.

 Five  water levels were  used on  alfalfa, feed  barley, and  malt barley.  Treatments
 2,  4  and 5 were  irrigated  with quantities  of  water sufficient to bring the soil
 to field capacity  (FC)  from 50% of the  available moisture  (AM), twice this
 quantity and four times this quantity,  respectively.  Treatments 1 and 3  were
 irrigated  to FC  when  90 and 10% respectively, of the AM was  depleted.  The
 highest  irrigation  level on alfalfa yielded an  average  of  2  mt/ha/yr less than
 level 1  over the 3  year study  and 1-1/2 mt/ha/yr less than level 2, which was
 the  check treatment.   The  phosphorus content  of  the forage was  reduced -by the
 two  driest irrigation levels and  could  require  P supplementation when fed to
 some  classes of  livestock.  The yield of feed barley for  the highest irrigation
 level was reduced 18% when compared to  the  driest  treatment.  The average yield
 of malt barley for  the  2 years was reduced  22%  by  irrigation level 5 compared to
 irrigation level 1.   An economic  analysis of  the plot yield  data showed that
 irrigation practice No. 1  provided the  largest  return to management and land.
 These results  suggest that irrigators might be  able to  reduce the quantity of
water used and increase yields as well.  An analysis of the  yield data for crops,
both  with and without  irrigation scheduling fIS), showed  that yields were
generally higher when  a crop was under  IS.   An  economic analysis of the yield
 increase for alfalfa  and barley indicated that  the increased yield would more
 than  pay for the cost of the IS service.  For the given physical situation and
 irrigation practices  similar to those used  in water level  3,  the drainage system
would cost $86/ha/yr,  for water level 4-$272/ha/yr, and for water level 5-
 $1038/ha/yr.


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  78:03F-097
  PERFORMANCE OF CENTER-PIVOT SPRINKLER IRRIGATION SYSTEMS OPERATING AT REDUCED
  PRESSURES /
  All, S.M.A., and Barefoot, A.D.
  Oklahoir*  State University, Stillwater,  Department of Agricultural Encrineerincr
  Paper N.,. 78-2005,  Presented at the 1978 Summer Meeting of the American Society
  14  re"   tUral Engineers, June 27-30,  1978,  Logan,  Utah,  19 p.   4 fig,  4 tab,
  Descriptors:   Sprinkler irrigation,  Irrigation systems,  Performance,  Water
  pressure,  Low flow,  Uniformity coefficient,  Distribution patterns,  Evaporation
  J- 1T3T iCfcl tlOTl *

  Spray distribution obtained  from a single stationary  sprinkler head was  utilized
  to determine  the effects  of  reduced  operating  pressure on evaporation loss,
  uniformity of application, sprinkler spacing,  and  application  rate  of a  center-
  pivot sprinkler  irrigation system.   Results  indicated that at  reduced pressure
  the  sprinkler performances were satisfactory.


  78:03F-098
  "CORNER PIVOT" AN EFFECTIVE  CORNER WATERING  SYSTEM,
  Callies, R.E.
  Lindsay Manufacturing Company,  Lindsay, Nebraska.
  Paper No.  78-2006, Presented at the  1978  Summer Meeting  of  the American  Society
  of Agricultural  Engineers, June 27-30, 1978, Logan, Utah,  18 p.

  Descriptors:  Sprinkler irrigation,  Irrigated  land, Irrigation efficiency,
  Irrigation systems, Design, Performance,  Distribution, Distribution systems,
  Irrigation.

 The "Corner Pivot" system incorporates the use of a long span single tower center
 pivot irrigation machine which  is attached to and pivots about the outer most
 tower of a conventional center pivot irrigation machine.   This attachment is used
 to extend the reach of the standard machine for the purpose of watering the
 corners  or irregularly shaped areas along the perimeter of the field which could
 not normally be reached by a conventional center pivot machine.


 78:03F-099
 MATHEMATICAL MODELS AND BORDER IRRIGATION DESIGN,
 Fangmeier,  D.D.,  and  Strelkoff, T.
 Arizona  University, Tucson,  Department of Soil, Water  and Engineering.
 Paper No.  78-2007, Presented  at the 1978  Summer Meeting of the  American Society
 of Agricultural Engineers, June 27-30, 1978,  Logan, Utah, 11 p.   11  fig,  4 tab,
 6 ref, 19 equ.

 Descriptors:   Border  irrigation, Irrigation design, Mathematical models,
 Evaluation, Runoff, Design criteria,  Infiltration rates,  Recession curves,  Time
 lag,  Irrigation efficiency.

 A mathematical model  of  flow  in irrigation borders  assuming zero  inertia  was  used
 to evaluate U.S.  Soil Conservation Service design criteria for  sloping borders
 with  runoff and to demonstrate  model  capabilities.   Model results  indicated that
 the Soil Conservation Service design  criteria are reasonable.


 78:03F-100
 BORDER-STRIP IRRIGATION  DESIGN—PRACTICAL  APPROACH  FROM A THEORETICAL BASIS,
 Merriam, J.L.
 California Polytechnic State  University, San  Luis Obispo,  Department of Agricultural
 Engineering.
 Paper No. 78-2008,  Presented at  the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June  27-30, 1978, Logan,  Utah,   14 p.  14 fig,  1 tab,
 2 ref, 3 equ.

 Descriptors:   Irrigation design, Border irrigation,  Surface irrigation, Graphical
methods,  Recession  curves. Flow  rates, Irrigation efficiency, Moisture deficit,
Time lag, Infiltration.



                                     147

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A graphical procedure was developed for designing border-strip irrigation
systems.  It is based on the principle that the shape of the recession curve
is relatively unchanging for any specific field, and therefore, it is the
controlling key condition for design or operation.  Conditions modifiable by
the designer or operator to obtain high efficiency are:  (1) the stream size
that controls the rate of advance; (2) the Management Allowed Deficiency of
soil moisture at the time of irrigation;  (3) the length of the strip; and
(4) the distance down the strip at which flow is cut off.


78:03F-101
RAPIDLY OBTAINING OPTIMAL IRRIGATION SYSTEM DESIGNS,
Busch, J.R., Galinato, G.D., Brockway, C.E., and Steinbach, G.E.
Idaho University, Aberdeen.
Paper No. 78-2009, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 16 p.  6 fig, 8 ref.

Descriptors:  Irrigation design, Irrigation systems, Irrigation, Optimization,
Computer programs, Computer models, Cost allocation, Costs, Dynamic programming,
Linear programming.

A methodology was developed and tested that will allow irrigation planners
to obtain optimal system designs.  Computer routines were used to obtain costs
of individual system components.  The optimization procedures produce least
cost designs subject to specified constraints and these constraints can easily
be changed to allow rapid evaluation of alternatives.


78:'03P-102
COMPUTER MODEL FOR CENTER PIVOT SPRINKLER DESIGN,
Kelso, G.L., and Jarrett, A.R.
Pennsylvania State University, University Park, Department of Agricultural
Engineering.
Paper No. 78-2003, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 19 p.  12 fig, 6 tab,
7 ref, 42 equ.

Descriptors:  Sprinkler irrigation, Computer models, Computer programs, Irrigation
systems, Flow rates, Uniformity coefficient, Irrigation design, Irrigation.

A computer aided center pivot design program was presented.  The program selected
specific sprinklers and nozzles from input parameters of flow rate to the pivot,
system length, sprinkler spacing and desirability of an endgun.  The program also
computed a uniformity coefficient for the system based on the sprinklers and
nozzles selected.


78:03F-103
THE USE OF COMPUTERS TO NOZZLE CENTER PIVOT SYSTEMS,
Morgan, R.M.
The Toro Company, Riverside, California  92504.
Paper No. 78-2002, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 8 p.

Descriptors:  Sprinkler irrigation, Distribution patterns, Computer programs,
Distribution, Nozzles, Irrigation systems. Water distribution (applied). Irrigation.

The practice of irrigation by sprinkler head distribution on center pivot machines
has been a system of application crops for nearly twenty years.  Many types of
heads and spacings have been used with a goal toward achieving more even distribution'
The art of computer-use to predetermine distribution uniformity was discussed.


78:03F-104
DETERMINING CENTER-PIVOT SPRINKLER UNIFORMITIES,
Ring, L., and Heermann, D.F.
Agriculture Center, Lethbridge, Alberta T1J 4C7, Alberta Agriculture.
Paper No. 78-2001, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 18 p.  3 fig, 6 tab,
12 ref, 4 egu.

                                     148

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Descriptors:  Sprinkler irrigation, Uniformity coefficient, Irrigation efficiency,
Distribution, Distribution patterns, Irrigation design, Evaluation, Irrigation.

Catch can evaluations were conducted and the water application and uniformity were
calculated for different can spacings and number of rows.  Results were compared
to each other and to a theoretical application pattern.  A recommended procedure
for the field evaluation of center-pivot systems was suggested.


78:03F-105
VARIABILITY OF SPRINKLER COEFFICIENT OF UNIFORMITY TEST RESULTS,
Solomon, K.
RainBird Technical Services, Logan, Utah.
Paper No. 78-2010, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 10 p.  2 fig, 2 tab,
4 ref.

Descriptors:  Sprinkler irrigation, Uniformity coefficient. Irrigation efficiency,
Statistical methods, Regression analysis. Variability.

Sprinkler coefficient of uniformity (UC)  test results were analyzed and found to
vary significantly, even under similar test conditions.  The amount of anticipated
variation in measured UC values was correlated with the UC value itself.  Factors
influencing this variation were discussed.


78:03F-106
REUSE PITS:  CHEAPEST WATER ON THE FARM,
White, J.G.
Denver, Colorado.
Irrigation Age, Vol. 13, No. 3, p 58, 62, November-December, 1978.  2 fig.

Descriptors:  Tailwater, Water conservation, Irrigation efficiency, Irrigation,
Crop production. Irrigation practices, Nebraska, Agricultural runoff.

This article describes the benefits of using tailwater pits as experienced by
farmers in Nebraska.  It was found that the pumping cost was reduced by one-
fourth compared with what it costs to pump from the deep wells, reduced the
time and labor, and reduced the amount of deep-well water use by 20%.  It was also
estimated that the gravity irrigation efficiency was increased by almost 15%.


78:03F-107
A PROGRAM TO PROMOTE IRRIGATION CONSERVATION IN IDAHO,
Hammond, J.
State of Idaho, Statehouse, Boise, Department of Water Resources.
Pacific Northwest Regional Commission, March, 1978.  43 p, 6 fig, 12 ref.

Descriptors:  Water conservation, Irrigation, Programs, Idaho, Water management
(applied), Water law, Water costs, Social aspects, Legal aspects, Water delivery.

This study investigated the economic, social, legal and institutional factors
affecting irrigation efficiency and sought incentives for promoting irrigation
water conservation.  This report presents the results of the study and outlines
alternatives for formulating a comprehensive irrigation conservation program.
Specifically, it discusses the promotion of irrigation water conservation, attitudes
and incentives involved in such conservation, water conservation aspects of Idaho
laws, and evaluates three alternative programs for pomoting irrigation water
conservation.


78:03F-108
CONSERVATION AND CONVENTIONAL SYSTEMS FOR CONTINUOUS PRODUCTION OF CORN,
Erbach, D.C., Lovely, W.G., and Ayres, G.E.
Iowa State University, Ames, Department of Agricultural Engineering.
Paper No. 78-2517, Presented at the 1978  Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 9 p.  4 fig, 9 tab, 22 ref.
                                     149

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 Descriptors:   Till,  Soil management,  Conservation, Crop production, Corn  (field),
 Economics,  Weed  control, Iowa.

 Seven tillage  systems were  evaluated  for  continuous production of corn in Central
 Iowa  on a soil from  the Clarion-Nicollet-Webster Soil Association.  Comparative
 week  control,  stand  establishment,  surface plant residue, soil nutrient profile,
 yield,  and  economic  results were  discussed.


 78:03F-109
 WATER BALANCE  IN IRRIGATED  SOILS,
 Botzan,  M., and  Merculiev,  O.
 Academy of  Agriculture and  Forest Sciences, Bucharest, Romania.
 ICID  Bulletin, Vol.  27, No. 2, p  23-29, 35, July, 1978.  26 ref.

 Descriptors:   Water  balance. Irrigation design, Irrigation programs, Consumptive
 use,  Soil-water-plant relationships.  Leaching, Evapotranspiration, Irrigation.

 The paper presented  the results obtained  by land experimental research works
 carried out in different pedoclimatic zones of Romania (temperate zone) between
 1945-1947 and  continuously  since  1951.  The water balance elements (initial
 reserve, final reserve, winter and  summer precipitations, groundwater supply, soil
 water consumption on different calculated probabilities on crops and pedoclimatic
 zones,  the  water application and  the  irrigation rates during the vegetation and
 supply  periods)  were quantitatively characterized.  Interrelationships of water
 consumption with the type of crop and pedoclimatic zone, soil humidity, air
 temperature, and crop yield were  established.  These correlations allowed for
 establishing an  indirect water-consumption calculation method.  For the irriga-
 tion  project designing model, the basic elements and the limitative conditions
 were  established.  Both the irrigation as required and irrigation by rotation
 were  analyzed  for the water application forecast and programming.  Also, the basic
 participating  elements of the model in the prognosis stage were established
 together with  the limitative conditions which determine the water application
 program in  the row for plots irrigated in a single rotation.


 78:03F-110
 LATERALLY CONFINED FLOW FROM A POINT  SOURCE AT THE SURFACE OF AN INHOMOGENEOUS
 SOIL  COLUMN,
 Merrill, S.D., Raats, P.A.C., and Dirksen, C.
 Northern Great Plains Research Center, P.O. Box 459, Mandan, North Dakota  58554.
 Soil  Science Society of America Journal, Vol. 42, No. 6,  p 851-857, November-
 December, 1978.   8 fig, 18  ref, 22 equ.

 Descriptors:   Confined water, Steady  flow, Infiltration,  Irrigation,  Hydraulic
 conductivity,  Irrigation design, Distribution, Pressure head, Water conservation.

 Solution of a  linearized flow equation for steady, axisymmetric, laterally
 confined infiltration from a point source located at the soil surface was com-
 pared with pressure  head patterns measured in an undisturbed column of sandy
 loam.  The geometry  approximated an array of trickle irrigation emitters.  The
 hydraulic conductivity could be represented as an exponential function of both
 the pressure head and the depth in the column.  This implied that steady, multi-
 dimensional flow  in  the column could be described by a linear flow equation.
Measured and predicted distributions of pressure head agreed most closely at an
 application rate of  0.5 cm/day.  Increase in the size of a saturated  zone about
 the point source at  application rates higher than 0.5 cm/day caused isolines
of pressure head to be distorted from the predicted shape.   Flow patterns for
 homogeneous and heterogeneous soil were compared.  Measured distributions of
pressure heads under intermittent trickle application were compared with steady
 infiltration patterns.   It was concluded that a steady-flow solution  will give
 an approximate prediction of intermittent pressure head patterns for  continuously
repeated application cycles over part of the flow region and during part of the
 time.


 78:03F-111
WATER BALANCE OF FLOODED RICE PADDIES,
Brown, K.W., Turner,  F.T.,  Thomas, J.C.,  Deuel, L.E., and Keener, M.E.


                                      150

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 Texas  A &  M University,  College Station, Department of Soil and Crop Sciences.
 Agricultural Water  Management, Vol.  1, No.  3, p 277-291, November, 1978.  10 fig,
 3  tab,  8 ref.
(See  78:021-037)


 78:03F-112
 REMOTE SENSING FOR  AGRICULTURAL WATER MANAGEMENT AND CROP YIELD PREDICTION,
 Idso,  S.B.,  Jackson,  R.D.,  and Reginato, R.J.
 United States Water Conservation Laboratory, Phoenix, Arizona.
 Agricultural Water  Management, Vol.  1, No.  4, p 299-310, December, 1978.  5 fig,
 32 ref,  5  equ.

 Descriptors:  Remote  sensing, Water  management (applied), Crop production,
 Scheduling,  Irrigation,  Albedo, Soil moisture, Evaporation, Reviews.

 This paper reviewed the  research conducted  at the U.S. Water Conservation
 Laboratory,  Phoenix,  Arizona over the past  several years relative to agricultural
 application of remote sensing.  In addition, new data were presented.  The
 subjects treated were soil  moisture, evaporation, irrigation scheduling, and
 crop yield estimation.   The analyses indicated that we have the technology at
 hand to successfully  integrate remote sensing techniques into agricultural
 operations designed to enhance production via intelligent water management.


 78:03F-113
 BEST USE OF CROP RESIDUES,
 Fenster, C.R., Follett,  R.H., and Williamson., E.J.
 Nebraska University,  Lincoln, Department of Agronomy.
 Crops  and  Soils Magazine, Vol. 30, No. 9, p 10-13, August-September, 1978.
 3  fig,  2 tab.

 Descriptors:  Feeds,  Crops, Organic  matter, Soil erosion, Energy.

 This paper looks at the  present and  some potential uses of crop residues.
 It concluded that the best  use of crop residues depends on the crop, the soil,
 the  location of the place where the  particular crop and soil exist, and a
 number  of  other problems directly and remotely related to agriculture.


 78:03F-114
 CHEMICAL INJECTION  POPULAR  IN NORTHWEST,
 Henry,  C.
 Irrigation Age, Northwest/Pacific Editor.
 Irrigation Age, Vol.  13, No. 3,'p 46-47, November-December, 1978.  3 fig.

 Descriptors:  Irrigation, Fertilizers, Fertilization, Chemicals, Sprinkler
 irrigation, Application methods, Application equipment, Injection.

 This article reports  and discusses the methods and benefits of applying liquid
 chemicals  and fertilizers with irrigation water.


 78:03F-115
 ELECTRONIC TIMERS FOR AUTOMATED SURFACE IRRIGATION SYSTEMS,
 Fisher, H.D., Humpherys, A.S., and Worstell, R.V.
 Snake River Conservation Research Center, Kimberly, Idaho, United States
 Department of Agriculture.
 Paper No.  78-2544,  Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20,  1978,  Palmer House Hotel,  Chicago,
 Illinois,  7 p.   3 fig, 5 ref.

Descriptors:  Surface irrigation,  Automatic control,  Control systems,  Automation,
Timing, Electronic  equipment.  Instrumentation,  Furrow irrigation, Irrigation
systems.

Electronic timers were developed to replace alarm clocks and mechanical timers
 for semirutomated irrigation structures and valves.   Timer-controllers including



                                     151

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 a micro-processor unit were designed for a field tested with automatic cutback,
 buried lateral and multiset furrow irrigation systems.


 78:03P-116
 VOLUMETRIC CONTROL FOR IRRIGATION AUTOMATION,
 Duke, H.R., Payne, M.L. , and Kincaid, D.C.
 Agricultural Research, Science and Education Administration, United States
 Department of Agriculture.
 Paper No. 78-2545, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 8 p.  3 fig, 4 ref.

 Descriptors:  Surface irrigation, Automatic control, Control systems, Automation,
 Electronic equipment, Instrumentation,  Irrigation programs, Irrigation systems.

 A digital electronic controller was developed for use in surface irrigation
 automation.   This controller has full random-multiplexing capabilities and is
 capable of integrating flow rates as measured through a nonlinear open channel
 flow measurement device.


 78:03F-117
 UTILIZATION  OF A PORTABLE SOLID STATE FURROW IRRIGATION VALVE  CONTROLLER,
 Edling,  R.J.,  Duke,  H.R. , and  Payne,  M.L.
 Nebraska  University,  Scottsbluff.
 Paper No.  78-2546, Presented at the 1978 winter  Meeting of  the American Society
 of Agricultural Engineers,  December 18-20,  1978,  Palmer House Hotel,  Chicago,
 Illinois,  13 p.   3 fig,  4 ref.

 ?*MnnPtarSi\  F^rOW  ^gation, Valves, Control  systems, Automation,  Instrumen-
 tation, Application  equipment,  Electronic equipment,  Irrigation  systems.

 Research was conducted during  the  summers of  1977-1978  on an USDA-SEA  controller
 to allow semi-automatic changing of  furrow  irrigation sets.  Two types of  control
 valves were used with the controller.  After  initial  diff iculties , satisfactory
 use was obtained with the controller and both types of  valves.   Additional work
 in an on-farm situation was advised before  the controllers  use is recommended.


 78:03F-118
 DIGITAL CONTROLLER FOR TRICKLE  IRRIGATION,
 Fangmeier, D.D., and  Busman, J.D.
 Arizona University, Tucson, Department of Soils, Water  and Engineering.
 Paper No. 78-2547, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago?
 Illinois, 7 p.   5 fig, 1  tab, 5 ref.

              Contr°l systems,  Irrigation systems, Water conservation, Electronic
use
                                                  ,            rvaon,   ec
   ipment, Evaporation, Soil moisture, Moisture tension, Timing, Consumptive
   , Application equipment.
                  er *aa*eBi<3ne* U8i*g complementary metal oxide semiconductor
™sr  *        controller uses measured evaporation pan depths and- soil
moisture tensions to determine the time required to apply the desired
of water on a daily basis.  Circuit diagrams for major components
78:03F-119
RESPONSE OF CORN TO LIMITED IRRIGATION ON SANDY SOILS,
Wilson, G.D. , Watts, D.G., and Fischbach, P.E.
2at«r8S U™V^ity£ N°rth ?latte' Department of Agricultural Engineering.
of lari-Jn™? *' *resented at the ^78 Winter Meeting of the American Society
Ulinois  S o  En9ineers, December 18-20, 1978' ^Uner House Hotel, Chicago,
(See 5^621-040)
                                     152

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 78:03F-120
 EVALUATION OF CROP WATER STRESS UNDER LIMITED IRRIGATION,
 Heermann, D., and Duke, H.
 Agricultural Research, Science and Education Administration, Fort Collins,
 Colorado, United States Department of Agriculture.
 Paper No. 78-2556, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicaero
 Illinois, 5 p.  8 fig, 8 ref.
 (See 78:021-041)


 78:03F-121
 IRRIGATED CORN YIELD RESPONSE TO WATER,
 Musick, J.T., and Dusek,  D.A.
 Southwestern Great Plains Research Center, Bushland, Texas, United States
 Department of Agriculture.
 Paper. No. 78-2557, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 26 p.   8 fig, 3 tab, 16 ref.
 (See 78:021-042}


 78:03F-122
 CORN YIELD RESPONSES TO WATER STRESS MANAGEMENT,
 Stegman,  E.G.,  and Aflatouni, M.
 North Dakota state University, Fargo,  Department of Agricultural Engineering.
 Paper No. 78-2558, Presented at the 1978 Winter Meeting of the American'Society
 of Agricultural  Engineers,  December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 9  p.   8  fig,  3  tab, 18  ref,  1 equ.
 (See 78:021-034)


 78:03F-123
 HARVESTING RUNOFF  FROM PRECIPITATION ON IRRIGATED LANDS,
 Manges, H.L.,  and  Mao,  L.-T.
 Kansas  Agricultural  Experiment Station,  Manhattan,  Kansas.
 Paper No. 78-2559, Presented at the 1978 Winter Meeting of  the American Society
 of Agricultural  Engineers,  December 18-20, 1978, Palmer House Hotel,  Chicago,
 Illinois, 10  p.  2 fig, 3  tab,  10  ref,  11 equ.

 Descriptors:  Water  harvesting, Runoff,  Precipitation  (atmospheric),  Tailwater,
 Climatic  data, Model studies,  Evapotranspiration, Water balance,  Irrigation,
 Corn Cfield).

 A  tailwater management model  was developed to simulate  runoff from precipitation
 on irrigated  land.   The model was  tested for corn using 25 years  of  climatological
 data for  Garden  City, Kansas.   Runoff from precipitation repumped onto  the field
 averaged  69 and  39 millimeters  annually  for two  commonly irrigated soils.
                                                        >

 78:03F-124
 THE  TIMELINESS BENEFIT OF SUBSURFACE DRAINAGE,
 Wendte, L.W., Drablos, C.J.W., and  Lembke,  W.D.
 Soil  Conservation Service, Kankakee, Illinois.
 Transactions of  the American  Society of Agricultural Engineering, Vol.  21, No.  3,
 p  484-488, May-June, 1978.  6 fig,  3 tab,  21 ref.

 Descriptors:  *Subsurface drainage, *Agriculture, *Benefits, *Model studies,
 Mathematical models, Planting management,  Farm management, Drains, Tile drains,
 Economics.

 A  simulation model was developed to predict available spring workdays and the
 earliest  possible planting dates for soils with  a subsurface drainage system.
Applying  the model to two Illinois  soils,  it was found  that as many as two available
workdays  in April and 19 days in May are gained by installing a recommended sub-
 surface drainage system.  The optimum drain spacing based on the timeliness benefit
of earlier corn planting ranged from 24 to  61 m, depending on permeability and  soil
 type.  The average annual timeliness benefit for installing the optimum subsurface
drainage  system was $37 to $156/ha.


                                     153

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 78.-03F-125
 WATER TABLE  DEPTH  AND IRRIGATION  EFFECTS  ON WATER USE  EFFICIENCIES OF  THREE CROPS,
 Benz,  L.C.,  Reichman,  G.A.,  Doering,  E.J., and Follett,  R.F.
 Agricultural Research Service, Northern Great Plains Research  Center,  Mandan,
 North Dakota.
 Paper No. 77-2039  presented  at the  1977 Annual Meeting of  the  American Society of
 Agricultural Engineers,  June 26-29,  1977,  Raleigh, North Carolina, 17  p.   7 fig,
 3  tab,  14 ref.

 Descriptors:  *Corn (field),  *Sugarbeets,  *Water  table, Irrigation effects, *Alfalfa*
 Irrigation,  Irrigation efficiency,  Irrigation practices.

 Production and  applied water-use  efficiencies  (AWUE) of  corn,  sugarbeets,  and alfalf*
 from  a 3-year field  experiment at three water table depths and four irrigation rates
 were  highest from  the shallow water table treatment without irrigation.


 78.-03F-126
 ESTIMATING SPRINKLER DISTRIBUTION PATTERNS USING LINEAR  REGRESSION,
 Karmeli, D.
 Colorado State  University, Fort Collins,  Department of Agricultural and Chemical
 Engineering.
 Transactions  of the  American Society  of Agricultural Engineers, Special Edition,
 Vol.  21SW, No.  4,  p  682-686, August  20, 1978.  5  fig,  2  tab, 5 ref, 9  equ.

 Descriptors:  Sprinkler  irrigation,  Distribution  patterns, Estimating  equations,
 Regression analysis,  Spatial distribution.

 The linear regression was used to describe sprinkler distribution patterns.  The
 linear fit was  found to  approximate  the distribution very well in a wide range.
 This approximation proved to produce  good estimates for both high and  low  quality
 distributions.  In the higher quality distributions, the linear regressions model
 estimated the actual field data as well as the normal model.  However, in  lower
 quality distributions  the linear  regression model proved significantly better than
 the normal model in  its  estimates.  A new coefficient, UCL, was suggested  for
 practical use.


 78:03F-127
 TRICKLE IRRIGATION UNIFORMITY AND EFFICIENCY,
 Solomon, K.,  and Keller, J.
 Rain Bird Technical  Services, Glendora, California.
 Journal of the  Irrigation and Drainage Division,  American Society of Civil Engineer*1
 Vol. 104, No, IR3, p 293-306, September,  1978.   5 fig, 1 tab,  8 ref, 16 equ.

 Descriptors:  Irrigation efficiency,  Irrigation practices, Water conservation,
 Uniformity coefficient, Water pressure, Water distribution (applied),  Pressure
 head,  Design criteria.

 Expressions were developed for the pressure head  in a trickle irrigation lateral
 and throughout  the pipe network for three common  types of manifolds.   Histograms
were drawn showing the distributions  of pressure  in typical trickle irrigation
 systems.  The distributions were  skewed toward the low head end, and the degree
 of s,kew depended on  the type of manifold and the  ratio of manifold head loss to
 lateral head loss.   Flow rate histograms were drawn showing the combined effects
on emitter discharge spread, manifold construction, head losses and variation in
emitter manufacture.  Coefficient of  manufacturing variation was shown to be as
 important a design consideration  as the amount of head loss in the system.  Values
of emission uniformity and absolute emission uniformity were tabulated for various
emitter and system configurations on  level ground.  It was pointed out that in
many cases the results of this study  can be applied to sloping terrain as well.


 78s03F-128
AUTOMATION OF ON-FARM IRRIGATION TURNOUTS UTILIZING JACK-GATES,
Dedrick, A.R., and Erie,  L.J.
United States Water Conservation Laboratory,  Phoenix, Arizona.
Transactions of the American Society  of Agricultural Engineers, Special Edition,
Vol. 21SW, No.  1, p  92-96, February 20, 1978.   6  fig, 3 tab, 7 ref.


                                      154

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Descriptors:  Irrigation, Surface irrigation, Automation, Automatic control,
Turnouts.

The design, development, and installation of equipment used to automate existing
single outlet turnouts  (jack-gates) on a 26.3-ha  (65-acre) field were described.
Specific jack-gate modifications and equipment requirements; control center
design associated with  safety overflow, excess water after irrigation, and
sequencing functions; and system operations were all discussed.


78:03F-129
THE ROLE OF EVAPOTRANSPIRATION MODELS IN IRRIGATION SCHEDULING,
Jensen, M.E., and Wright, J.L.
Snake River Conservation Research Center, United States Department of Agriculture-
Agricultural Research Service, Kimberly, Idaho.
Transactions*of the American Society of Agricultural Engineers, Special Edition,
Vol. 21SW, No. 1, p 82-87, February 20, 1978.  4 fig, 2 tab, 25 ref, 3 equ.
(See 78:020-007)


78:03F-130
AUTOMATION OF AN OPEN-DITCH IRRIGATION CONVEYANCE SYSTEM UTILIZING TILE OUTLETS,
Erie, L.J., and Dedrick, A.R.
United States Water Conservation Laboratory, Phoenix, Arizona.
Transactions of the American Society of Agricultural Engineers, Special Edition,
Vol. 21SW, No. 1 p 119-123, February 20, 1978.  6 fig, 6 ref.

Descriptors:  Irrigation ditches, Automation, Automatic control, Tiles,
Irrigation, Conveyance  structures.

Nearly 80% of the irrigated lands in the United States use surface irrigation
techniques.  Most of the on-farm, irrigation-water distribution systems are of
the open-ditch type.  The latest trend in western Arizona and parts of California
is to dead-level fields, then irrigate from single or multiple outlets with large
streams of water.  These level basins are well adapted to automation.  An automated
irrigation system reduces farm labor requirements and, as an irrigation management
tool, can reduce water  application, improve crop production, and minimize scalding
and thus stand loss.  A 28.4-ha  (70-acre) field irrigated with tile outlets was
pneumatically automated using two types of pillows on the outlet side, in combina-
tion with automated jack-gates, from a centrally located concrete-lined canal.
The present system is being used by the farmer, observed and amended by the
researchers, and demonstrated to many U.S. and foreign visitors.
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                                   SECTION  XVI


                     WATER QUANTITY MANAGEMENT AND CONTROL

                  CONTROL OF WATER ON THE SURFACE (GROUP 04A)
 78:04A-001
 A STOCHASTIC MODEL OF THE OPERATION OF A STREAM-AQUIFER SYSTEM,
 Flores, E.Z., Gutjahr, A.L., and Gelhar, L.W.
 New Mexico Institute of Mining and Technology, Socorro.
 Water Resources Research, Vol. 14, No. 1, p 30-38, February, 1978.  3 fig, 1 tab,
 34 ref.

 Descriptors:  *Reservoir operation, *Stochastic processes, *Linear programming,
 *Water management  (applied) , Optimization, Aquifers, Streams, Decision making.
 Effects, Wells.

 A simple lumped parameter stochastic model for optimal water management in a
 stream-connected aquifer system is examined.  The physical system is represented
 by a linear reservoir model, and a conditional probability approach is used to
 estimate the effect of parameter variability.  A drawdown correction is used to
 incorporate the local drawdown of the wells and is a crucial part of the model.
 A management analysis is accomplished by using a linear decision rule to minimize
 the expected value of the discounted costs with appropriate chance constraints,
 and the resulting nonlinear optimization problem is solved iteratively using a
 standard linear programming package.  In order to evaluate the limitations of the
 lumped parameter model in a management context, the results of the management
 technique are compared with results from Maddock (1974)  who used a distributed
 representation of the aquifer.   The conclusions of this  analysis indicate that
 stochastic effects are not very important in arriving at an operating policy but
 are important in determining the expected cost.


 78:04A-002
 A  VARIATIONAL INEQUALITY METHOD APPLIED TO FREE SURFACE  SEEPAGE FROM A TRIANGULAR
 DITCH,
 Bruch,  J.C.,  Jr.,  and Sloss,  J.M.
 California University,  Santa Barbara,  Department of Mechanical and Environmental
 Engineering.
 Water Resources  Research,  Vol.  14,  No.  1,  p 119-124,  February,  1978.   2 fig,
 2  tab,  12  ref.

 Descriptors:   *Mathematical models,  *Seepage,  *Ditches,  Drains,  Equations,  Ground-
 water movement.  Numerical  analysis,  Free  surfaces,  Soils,  Depth.

 Two-dimensional  seepage  from  a  single  triangular channel into  permeable soil
 underlain  at a finite depth by  a drain was  solved by  reducing  the  problem  to a
 variational inequality.  The  results obtained  consist of the location of the free
 surface, and thus,  the shape  of the  seepage region,  the velocity potential  and
 stream  function  at  a series of  mesh  points, and  the seepage flow rate.  The
 successive overrelaxation method with  projection was  used  to solve the-numerical
 problem.  The numerical  results compared very  favorably with the analytical
 solution to the  same problem.


 78:04A-003
 INTERTEMPORAL ALLOCATION OF IRRIGATION WATER IN THE MAYURAKSHI PROJECT  (INDIA),
AN APPLICATION OF CHANCE-CONSTRAINED LINEAR PROGRAMMING,
Maji, C.C., and Heady, E.O.
 Indian Agricultural Research  Institute, New Delhi, Water Technology Centre.
Water Resources Research, Vol.  14, No. 2, p 190-196, April, 1978.  10 tab,  29
equ, 14 ref.
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  Descriptors:   "Irrigation water,  *Water allocation  (applied),  *Linear program-
  ming,  *Reservoir operation,  "Cropping pattern,  *Chance-constrained models,
  Projects, Water policy, Optimization, Economic  efficiency.

  Developed is an optimal cropping  pattern and a  reservoir management policy for
  the Mayurakshi irrigation project in India.  Two chance-constrained linear
  programming models are formulated to account for the stochastic nature of the
  monthly inflows.  The models also consider the  increased economic opportunity
  offered by the introduction of new high-yielding crop varieties.  The results
  clearly indicate that a change in the existing  cropping pattern and reservoir
  management policy is desirable and is consistent with the maximization of net
  return to the project area.  The existing supply of nitrogen fertilizer in the
  command area is found to be inadequate to allow for the best use of other re-
  sources, including irrigation water.  As the probability of occurrence of a
  drought or a flood is kept within a limit of 10%, the crop activities in the
  optimal cropping pattern suffer from drought or flood conditions no more than
  10% of the time.  Thus the resulting cropping patterns should be preferred by
  the -tradition-bound farmers of the command area, who have a low risk-bearinq
  ability.                                                                   y


  78:04A-004
 SEQUENTIAL EXPLICITLY STOCHASTIC LINEAR PROGRAMMING MODELS:  A PROPOSED METHOD
 FOR DESIGN AND MANAGEMENT OF MULTIPURPOSE RESERVOIR SYSTEMS,
 Houck, M.H.,  and Cohon, J.L.
 Purdue University,  Lafayette, Indiana,  School of Civil Engineering.
 Water Resources Research,  Vol.  14, No.  2,  p 161-169, April, 1978.   12  ref.

 Descriptors:   "Multiple-purpose reservoirs,  *Reservoir design,  "Reservoir
 operation,  "Linear  programming, "Stochastic  processes,  "Nonlinear  programming,
 "Economic efficiency,  Optimization,  Water  management (applied), Operating rules.

 A sequential  explicitly stochastic linear  programming model (SESLP) which con-
 sists of a  nonlinear  program and an algorithm for obtaining an  approximate  solu-
 tion is presented.  The SESLP model can  be used to determine for a multipurpose
 multiple-reservoir  system either both a  design and a management policy  or only  a
 management  policy. , A discrete  lag-one Markov process is  explicitly included  in
 the model as  the streamflow description.   The approximate solution to  the non-
 linear program is obtained by sequentially solving two linear programs which  are
 subsets of  the nonlinear program.   A method  of significantly reducing the compu-
 tational burden and data requirements of the SESLP model  is also presented.   The
 method (system coordinated performance-individual operation (Scorpio))  is effec-
 tive because  within the SESLP/Scorpio model,  although the operating rules for
 each reservoir are  dependent on events occurring only at  that reservoir  site,
 system-wide performance levels  are measured  and  the  operation of each reservoir
 is  coordinated with all other reservoirs.  Problem objectives include food loss
 minimization  and benefit maximization.


 78:04A-005
 EFFECT OF DRAIN TUBE OPENINGS ON WATER-TABLE  DRAWDOWNS,
 Skaggs,  R.W.
 North  Carolina  State University at Raleigh, Department of Biological and Agricul-
 tural  Engineering.
 Journal of the  Irrigation and Drainage Division,  American  Society of Civil
 Engineers, Vol. 104, No 1R1, Proceedings Paper 13606, p 13-21, March, 1978.   5
 fig, 2  tab, 13  ref, 1 append.

 Descriptors:  "Tile drainage, "Drawdown, "Model  studies, Mathematical models,
 Drains, Tile drains, Groundwater, Soil water, Soil water movement, Filters.

 Conventional methods assume that the drain tube  is completely open and offers no
 resistance to the entry of water.  An approximate method of determining the
 effect of drain tube openings on water table drawdown was presented,  based on the
 use of Hooghoudt's equivalent depth to account for convergence near the drain
 during water table drawdown.  Data from the literature were used to define an
 effective drain tube radius, r sub e, for drains with a finite number of open-
 ings.  The r sub e value was used then to define the Hooghoudt equivalent depth
which was, in turn,  used in solutions to the Boussinesq equation for water table


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drawdown.  The use of an envelope wrap material will permit a somewhat wider
drain spacing for all cases with a large increase in spacing for the deeper
profile.  The allowable increase in spacing for both cases was relatively small,
and the total system cost with the envelope wrap was about 6% higher than with-
out the wrap for the shallow profile and about 7% lower for the deep profile.


78:04A-006
HYDROLOGIC IMPACT OF GRAZING ON INFILTRATION:  A CRITICAL REVIEW,
Gifford, G.F., and Hawkins, R.H.
Utah State University, Logan, College of Natural Resources, Watershed Science
Unit.
Water Resources Research, Vol. 14, No, 2, p 305-313, April, 1978.  5 fig, 4 tab,
37 ref.

Descriptors:  Grazing, Infiltration, Infiltration rates, Hydrologic aspects,
Reviews, Ranges, Runoff, Hydrographs, Water yield.

The hydrologic importance of grazing is receiving increased attention on range-
lands in the United States.  The literature on this topic is fragmented.  This
paper explores the available literature for information useful in understanding
the hydrologic impacts of grazing intensity as related primarily to infiltration
and runoff.  Generally, data relative to range condition are not adequate for
evaluating hydrologic impacts.  Data relating grazing intensity to infiltration
rates are available, yet distinct limitations are evident.  These limitations
are discussed in terms of identifying future research needs.  The greatest need
appears to be a detailed definition of the long-term effects of grazing  (by year
and season) on infiltration rates as a function of site, range condition, and
grazing intensity.  Once obtained, infiltration rates must be coupled with an
appropriate method for generating runoff volumes, storm hydrographs, and long-
term water yields.


78:04A-007
A KINEMATIC MODEL FOR SURFACE IRRIGATION,
Sherman, B., and Singh, V.P.
New Mexico Institute of Mining and Technology, Socorro, New Mexico  87801.
Water Resources Research, Vol. 14, No. 2, p 357-364, April, 1978.  10 fig, 41
ref, 46 equ.

Descriptors:  Surface irrigation, Mathematical models, Analytical techniques,
Infiltration, Hydrodynamics, Momentum equation.

A kinematic wave model is developed to study surface irrigation.  Depending on
the variability of infiltration and the kinematic wave friction parameter, three
cases are distinguished.  Explicit analytical solutions are obtained for the
case when infiltration is constant, and a possible approach is suggested for the
case when it is not.


78:04A-008
RESERVOIR STORAGE WITH DEPENDENT, PERIODIC NET INPUTS,
Troutman, B.M.
Geological Survey, Denver, Colorado, Water Resources Division.
Water Resources Research, Vol. 14, No. 3, p 395-401, June, 1978.  5 fig, 20 ref.

Descriptors:  *Reservoirs, *Reservoir storage, *Storage capacity, *Projections,
^Stochastic processes, Inflow, Water demand, Time series analysis. Seasonal,
Storms.

Two random quantities, the range and the maximum deficit, which may provide a
measure of the required storage capacity of a reservoir over a fixed length of
time, are considered.  Interest in the range from an engineering point of view
was initiated by Hurst (1951), who demonstrated that for certain geophysical
time series, sample values of the range exhibit a property that has subsequently
become known as the "Hurst phenomenon".  This property is discussed briefly,
primarily with the intention of showing that the Hurst phenomenon can be inter-
preted so as to be consistent with the asymptotic results on the range.  The
second quantity, the maximum deficit, is simply the.storage obtained when one


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 applied the  sequent  peak  algorithm.   Of  primary  concern  is  the manner  in which
 the  statistical  behavoir  of  these  quantities  is  affected by dependence and  per-
 iodicity in  the  net  inputs to  the  reservoir.   Dependence, sometimes  referred  to
 as persistence or  serial  correlation,  is seen, for  example,  in the fact that  a
 large  stream discharge  on a  given  day will  tend  to  be  followed by a  large dis-
 charge on the next day.   The periodicities  are due  primarily to  seasonal
 variations in factors such as  precipitation and  demand for  stored water.


 78:04A-009
 FLAT CHANNEL TERRACES FOR POLLUTION ABATEMENT AND SEDIMENT  CONTROL,
 Buchta,  H.G., Liesemeyer, W.W., and Jackson,  L.G.
 United States Department  of  Agriculture,  Soil Conservation  Service,  Grand Island,
 Nebraska.
 Paper  No.  78-2521, Presented at the 1978 Winter  Meeting  of  the American Society
 of Agricultural  Engineers, December 18-20,  1978, Palmer  House Hotel, Chicago,
 Illinois,  5  p.   1  fig,  4  ref.

 Descriptors:  Terracing,  Pollution abatement, Sediment control,  Runoff, Crop
 production,  Semiarid climates, Computer  programs, Diversion, Gullies,  Nebraska.

 Flat channel terraces have been effectively used to control  and  use  runoff
 water.   The  runoff can  help  stabilize  crop  production  in a  simiarid  climate.
 Parallel flat channel terraces are growing  in popularity.


 78:04A-010
 PARALLEL TERRACES  ON FLAT SLOPES,
 Fryrear,  D.W., and Archer, E.
 United States Department  of  Agriculture,  Big  Spring, Texas.
 Paper  No.  78-2522, Presented at the 1978  Winter  Meeting  of  the American Society
 of Agricultural  Engineers, December 18-20,  1978, Palmer  House Hotel, Chicago,
 Illinois,  15 p.  2 fig, 1 tab, 8 ref.

 Descriptors:  Terracing,  Slopes, Slope stabilization,  Soil conservation, Water
 conservation, Crop production, Dryfarming,  Texas, Runoff, Economic justification.

 West Texas has more  terraces constructed  each year then  most states.   This manu-
 script describes the design, layout, and  construction  of parallel terracing
 systems  in this  part of the  state.  Several farmers were interviewed concerning
 their  feelings about parallel terraces and why they are  used on  their  farms.
 The  farmers  are  enthusiastic with  the benefits of terraces particularly if they
 are  involved in  the  design and construction of the system.  Despite the point
 rows, more skilled operators, and  increased time in the  field, some producers
 feel that  the increased production from  terraced fields  will pay for the con-
 struction  costs  in four to five years.


 78:04A-011
 DESIGN AND OPERATION OF GRADIENT TERRACE  SYSTEMS,
 Bondurant, D.T., and Laflen, J.M.
 Soil Conservation  Service, Des Moines, Iowa.
 Paper  No.  78-2520, Presented at the 1978  Winter Meeting  of the American Society
 of Agricultural  Engineers, December 18-20,  1978, Palmer  House Hotel, Chicago,
 Illinois,  7-p.   4  fig,  5  tab, 19 ref.
 (See 78:02J-006)


 78:04A-012
LAND USE EFFECTS ON CLAYPAN SOIL HYDROLOGY,
Kramer,  L.A., and Burwell, R.E.
Science  and  Education Administration, Federal Research,  Columbia, Missouri,  United
States Department of Agriculture.
Paper No.  78-2070, Presented at the 1978  Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan,  Utah, 14 p.   7 tab, 5 ref.

Descriptors:   Land use,  Water yield, Land management, Clays, Runoff,  Surface
runoff, Corn (field), Wheat,  Fallowing, Pastures.
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Water yield data  from  0.02-acre research plots for a ten-year study period of
constant  land use treatments are presented.  The SCS Curve Number Procedure for
runoff prediction gave ten-year average annual runoff values very similar to the
observed  land cover of fallow, continuous corn, small grain, and rotation
meadow.


78:04A-013
CONTROLLING IRRIGATION RUNOFF LOSSES WITH PROPER MANAGEMENT,
Fitzsimmons, D.W., Busch, J.R., Lewis, G.C., and Berg, C.W.
Idaho University, Moscow, Department of Agricultural Engineering.
Paper No. 78-2090, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 14 p.  1 fig, 9 tab,
8 ref.

Descriptors:  Surface  runoff, Runoff, Tailwater, Erosion, Water management (applied) i
Pollutants, Surface irrigation, Water loss, Sediment control, Nutrient removal.

Field investigations to determine the effectiveness of irrigation, tillage and
other practices in controlling surface runoff and resulting pollutant losses
from surface-irrigated fields were conducted during two irrigation seasons.  The
results indicate  that  water, sediment and nutrient losses can be reduced or
eliminated by the use  of proper management practices.


78:04A-014
CHEMICAL CHARACTERIZATION OF THE GASEOUS AND LIQUID ENVIRONMENTS OF SUBSURFACE
DRAIN SYSTEMS,
Meek, B.D., Grass, L.B., and MacKenzie, A.J.
Imperial Valley Conservation Research Center, Brawley, California.
Soil Science Society of America Journal, Vol. 42, No. 5, p 693-698, September-
October, 1978.  3 fig, 6 tab, 14 ref.
(See 78:02K-052)


78:04A-015
EFFECTS OF DRAINAGE PROJECTS ON RUNOFF FROM DEPRES.SIONAL WATERSHEDS,
Moore, I.D., and  Larson, C.L.
Minnesota University,  St. Paul, Department of Agricultural Engineering.
Paper No. 78-2504, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 5 p.

Descriptors:  Drainage effects, Drainage practices, Surface drainage. Subsurface
drainage, Surface runoff, Subsurface runoff. Peak discharge, Small watersheds,
Mathematical models, Statistical methods.

Runoff from watersheds characterized by numerous depressions was studied
statistically and by use of a special purpose watershed model.  Application of
the model to two small watersheds indicated that drainage development increases
annual runoff, storm runoff and peak discharges.


78:04A-016
LEACHING CONTROL CAN'T BE PERFECT,
Larsen, R.
Irrigation Age, Associate Editor.
Irrigation Age, Vol. 13, No. 2, p 49, October, 1973.  1 fig.

Descriptors:  Leaching, Leachate, Nitrogen, Nitrates, Irrigation, Scheduling,
Water pollution, Nebraska.

This article reported  the study to minimize losses from leaching conducted on
sandy soils by some members of the Agricultural Engineering Department, University
of Nebraska-Lincoln.  The major conclusion of the study was that scheduling
of irrigations to minimize percolation and proper selection of nitrogen (N)
amount and source can have a significant effect on nitrate leaching loss when
corn is produced on sandy soils.   The study, however, indicated that reducing
the loss to zero is not a practical goal on sandy'soils.


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78:04A-017
INFLUENCE OF ROW SPACING OF GRAIN SORGHUM ON GROUND COVER, RUNOFF, AND EROSION,
Adams, J.E., Richardson, C.W., and Burnett, E.
Grassland, Soil and Water Research Laboratory, P.O. Box 748, Temple, Texas
76501.
Soil Science Society of America Journal, Vol. 42, No. 6, p 959-962, November-
December, 1978.  4 fig, 2 tab, 9 ref.

Descriptors:  Runoff, Surface runoff, Erosion, Soil erosion, Canopy, Rainfall,
Rainfall intensity, Grain sorghum. Cover crops.

A study was begun at Temple, Texas, in 1972 to assess the effect of narrow (50-cm)
and conventional (100-cm) row spacing of grain sorghum on runoff and erosion from
field-sized areas.  Sorghum in narrow rows established a more complete plant
canopy earlier than sorghum with conventional row spacing and provided more ground
cover for much of the growing season.  In 1973, runoff was 45% less and soil loss
was 39% less from narrow-row grain sorghum than from sorghum with conventional
row spacing.  Narrow-row spacing of sorghum increased ground cover significantly
(5% level) 35 days after emergence in 1974.  Canopy cover was at maximum by 63
days after seeding emergence and provided a ground cover of 46 and 81% for sorghum
with 100- and 50-cm row spacing, respectively.


78:04A-018
SEEPAGE CONTROL BY PARTICLE SIZE SELECTION,
Hauser, V.L.
Science and Education Administration, Temple, Texas, Grassland-Forage .Research
Center.
Transactions of the American Society of Agricultural Engineers, Vol. 21, No.  4,
p 691-695, July-August, 1978.  9 fig, 1 tab, 12 ref.  .

Descriptors:  *Linings, *Clays, *Gravels, *Aggregates, *Seepage control, Canal
linings, Reservoirs, Canals, Hydraulic conductivity, Permeability, Soils, Sands,
Seepage.

Earth linings are used frequently in reservoirs, canals, and other earth structures
to control liquid movement for the purposes of pollution control, water conserva-
tion, and structural stability.  Clays or chemicals often are added to linings to
reduce the hydraulic conductivity of the native soil; however, both additives
sometimes decrease in effectiveness with time.  Under ordinary conditions, gravel
is nearly inert and does not change properties with time.   The hydraulic conductivity
of permeable soil was reduced substantially by adding gravel that was at least 15
times larger than the particle size of the soil.  The amount of clay required to
control seepage was reduced by half by the addition of gravel.
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                                  SECTION XVII


                    WATER QUANTITY MANAGEMENT AND  CONTROL

                       GROUNDWATER MANAGEMENT (GROUP 04B)


 78:048-001
 WATER SUPPLY DILEMMAS OF GEOTHERMAL DEVELOPMENT IN THE IMPERIAL VALLEY OF
 CALIFORNIA,
 Layton, D.W.
 California University, Livermore, Lawrence Livermore Laboratory.
 Water Resources Bulletin,  Vol. 14,  No. 1, p 133-143, February, 1978.  4 fig,
 22 ref.

 Descriptors:  *Geothermal studies,  *Therraal powerplants, *California, *Cooling
 water, *Water supply, *Imperial Valley (California), *Salton Sea (California),
 Water resources, Powerplants, Water requirements.

 There are four known geothermal resource areas in the Imperial Valley that have
 a combined potential of over 4,000  megawatts of electrical energy for 25 years.
 Water resources available to support geothermal energy development are imported
 Colorado River water, agricultural  waste waters, Salton Sea water,  and ground-
 water.  In addition,  geothermal power plants can produce their own cooling water
 from steam condensate.  Nevertheless, the relatively high water requirements of
 geothermal facilities along with a  series of real  and potential constraints may
 cause water supply dilemmas involving both the acquisition and use of cooling
 water.  Important constraints are institutional policies,  water supply costs,
 technical problems, and impacts upon the Salton Sea.  These constraints and
 related dilemmas were examined in light of relevant information on the valley's
 water resources, geothermal resources and energy technologies, cooling water
 requirements, and water supply options.


 78:04B-002
 ARTIFICIAL GROUNDWATER RECHARGE WITH CAPILLARITY,
 Ortiz, N.V., Duke, H.R.,  Sunada,  O.K., and McWhorter,  D.B.
 Colorado State University,  Fort Collins,  Department of Civil Engineering.
'journal of the Irrigation  and Drainage Division, American Society of Civil
 Engineers, Vol.  104,  No.  1R1, Proceeding Paper 13627,  March, 1978.   11 fig,
 1 tab, 21 ref.

 Descriptors:  *Groundwater  recharge,  *Capillary action,  *Artificial recharge,
 •Numerical analysis,  *Model studies,  *Capillary flow,  *Capillary zone, *Ground-
 water mounds, Water table,  Porous media.

 The effect of capillarity on the  transient response of the  water table to
 recharge was evaluated by a numerical and a porous media model.   The numerical
 model was developed to simulate the  growth and spread  of groundwater mounds,
 taking into consideration the flow and storage in  the  capillary regions.   The
 contribution 'from the capillary region was  described analytically in terms of
 recharge rates and the measureable soil properties of  bubbling pressure, pore-
 size distribution index, and hydraulic conductivity.   The numerical model  was
 verified by comparing its predictions for various  flow conditions with the
 result obtained  from  the porous media model.   The  effects of bubbling-pressure
 head,  pore-size  distribution index,  initial saturated  depth, depth  to water
 table, and recharge rate on the predicted mound height were determined.  It was
 shown that the effect of the capillary region  significantly influences the
 growth and spread of  groundwater  mounds.


 78:04B-003
 DIURNAL PERIODICITY IN GROUNDWATER RECHARGE RATES,
 Webb,  S.N.,  and  Watson, K.K.
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New South Wales University, Kensington, Australia, School of Civil Engineering.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 104, No. IRl, Proceedings Paper 13613, March, 1978.  2 fig,
1 tab, 11 ref.

Descriptors:  *Groundwater recharge, *Groundwater, *Algae, *Permeability,
*Pore pressure, *Diurnal, *Australia, Frequency, Pore water, Pit recharge.

In an investigation of the flow characteristics of a recharge pit used for
artificial groundwater recharge purposes, diurnal variations of a cyclic nature
were detected in the intake rate.  The output from soil water pressure sensors
installed between the base of the pit and the water table indicated similar
cyclic variations.  The maximum intake rate occurred regularly each day at
approximately 2 a.m. - 3 a.m. and the minimum approximately 12 hours later.  It
was concluded that these variations are due to the activity of algae on the base
of the pit and in the top layer of sand.  Diurnal peaks and troughs of the algae
oxygen production result in changes in the hydraulic conductivity of the pro-
file.  This would appear to be related to changes in the volume of the occluded
oxygen which exists as bubbles in the soil pores.  These reduce the flow area
available for recharge and thus cause a reduction in the intake rate.


78:046-004
MANAGEMENT ASPECTS OF CYCLIC STORAGE OF WATER IN AQUIFER SYSTEMS,
Greydanus, H.W.
State of California, Resources Agency, Department of Water Resources, Box 388,
Sacramento  95802.
Water Resources Bulletin, Vol. 14, No. 2, p 477-480, April, 1978.

Descriptors:  Aquifer systems, Groundwater basins, Water storage, Water manage-
ment (applied), California, Legal aspects, Water quality, Water rights, Water
law, Environmental effects.

Most of California's precipitation falls at the wrong place in the wrong season
in relation to the water needs.  Redistribution and regulation are essential.
Aquifer systems - groundwater basins - can provide a share of the future cyclic
storage regulation.  There are some differences in management concepts in using
a full basin in comparison with a partially dewatered basin.  Legal, water
quality, and physical impacts on aquifer systems, including subsidence, are
concerns.  Storage may be for the benefit of overlying water users or for dis-
tant areas.  Extraction during dry periods or recharge methods will require
careful planning.  Existing rights and uses and equitable treatment of all
parties must be assured.  Financial compensation may be involved.  Changes in
methods of operation or degree of self-determination by affected water agencies
will require committed watermanship to resolve.  Legislation or amendments to
organic acts may be needed but much can be accomplished within existing statutes.
Environmental impacts which can be avoided by not using large surface storage
sites are important.  Energy for pumping will be a key consideration.  About
40% of California is underlain by aquifer systems.  This resource offers major
potential in overcoming the maldistribution of natural water resources.


78:048-005
SUBSURFACE DRAINAGE OF AN ALLUVIAL CLAY SOIL FOR SOYBEANS,
Carter,  C.E., and Camp, C.R.
P.O. Drawer U, University Station, Baton Rouge, Louisiana  70893.
Paper No. 78-2040, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers,  June 27-30, 1978,  Logan,  Utah, 6 p.   3 fig,  2 tab,
7 ref.

Descriptors:  Subsurface drainage. Subsurface drains. Soybeans,  Crop response,
Crop production,  Clays, Louisiana, Economic feasibility.

A subsurface drainage field experiment was conducted on a 4 ha site of an
alluvial clay soil in Tensas Parish, Louisiana, during 1974-1977.  Subsurface
drains spaced 7.5 and 15 m apart did not effectively control the water table but
the soil water regime near the drains was improved somewhat.  Soybean yields were
significantly increased by this improved drainage three of four years with drains
spaced 7.5 m apart and two of four years with drains spaced 15 m apart.


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 78:048-006
 FIELD EVALUATIONS OF GROUNDWATER CONTROL BY TRENCH AND TRENCHLESS METHODS OF
 INSTALLED DRAINS—LOWER RIO GRANDE VALLEY OF TEXAS,
 Vittetoe, G.C., and Garner, B.J.
 Soil Conservation Service, Temple, Texas, United States Department of Agricul-
 ture.
 Paper No. 78-2043, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Utah, 6 p.  7 fig.

 Descriptors:   Subsurface drainage, Subsurface drains, Drainage practices,
 Trenches, Installation, Salinity, Flow rates, Groundwater, Water quality con-
 trol, Texas.

 This paper presents the result of field evaluations of the flow performance of
 209 subsurface drainage systems in the Lower Rio Grande Valley of Texas.  These
 drain systems  are installed to control groundwater and serve as artificial sub-
 surface drainage arteries for salinity management in an irrigated area.  Of the
 209 examined installations, 141 were installed by the trench method and 68 by
 the trenchless method.  All systems were installed in calendar years 1975 and
 1976, and all  utilized perforated corrugated plastic tubing, of 4- to 6-inch
 diameter size, and nylon fabric filters.  The evaluations reveal the ability
 Of the 209 drain systems to discharge flow in the prescence of a groundwater
 flow source, with the surface of the groundwater variously ranging from 2 to 6
 feet below the ground surface.  The data displays a strong general disparity in
 the unit flow  for systems installed by the trench and trenchless methods, with
 the trench method showing a noticeably higher flow performance for seemingly
 similar conditions.  In repeated instances, the flow performances of systems
 installed by the trenchless method were less than that believed to be needed to
 satisfy minimal drainage coefficients for the area.


 78:04B-007
 ANALYSIS OF COMBINATION SURFACE-SUBSURFACE DRAINAGE SYSTEMS FOR HUMID REGION
 SOILS,
 Skaggs, R.W.
 North Carolina State University, Raleigh, Department of Biological and Agricul-
 tural Engineering.
 Paper No. 78-2541, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 16 p.  13 fig, 5 tab, 20 ref, 3 equ.

 Descriptors:  Surface drainage, Subsurface drainage, Drainage systems, Drainage,
 Simulation analysis, Trafficability, Humid areas, Humid climates, Model studies,
 Crop production.

 Various designs of combination surface-subsurface drainage systems were analyzed
 by simulating their performance over twenty-five years of climatological record.
 Simulations were conducted and results analyzed for four soils at three loca-
 tions:  Jacksonville, Florida, Wilmington, North Carolina, and Columbus, Ohio.


 78-.04B-008
 INCORPORATING CROP NEEDS INTO DRAINAGE SYSTEM DESIGN,
 Ravelo, C.J., Reddell, D.L., Hiler, E.A., and Skaggs, R.W.
 Texas A & M University, College Station, Department of Agricultural Engineering.
 Paper No. 78-2540, Presented at the 1978 Winter Meeting of the American-Society
 of Agricultural Engineers, December 18-20, -1978, Palmer House Hotel, Chicago,
 Illinois, p 20.

 Descriptors:  Drainage practices, Drainage systems, Drainage, Computer models,
Water table, Soil water, Soil-water-plant relationships, Simulation analysis,
 Crop production, Water management (applied).

An improved approach is proposed for incorporating crop drainage requirements
 into drainage design procedures.   The overall methodology links crop drainage
 requirements, climatological data, and drainage theory into a workable design
method through incorporation of the stress-day index concept into a water manage-
ment model.   (Skaggs, 1975.   A water management model for high water table soils-
 Paper No. 75-2524, ASAE Winter Meeting.)


                                    164

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 78:04B-009
 SUBSURFACE DRAIN SPACING FROM WATER TABLE AND OUTFLOW MEASUREMENTS,
 Michener,  D.W.,  Schwab,  G.O.,  Skaggs,  R.W.,  Gordos,  J.D.,  and Olosky,  C.J.
 North Carolina State University,  Raleigh,  Department of Biological and Agricul-
 tural Engineering.
 Paper No.  78-2536,  Presented at the 1978  Winter  Meeting of the American Society
 of Agricultural Engineers,  December 18-20,  1978,  Palmer House Hotel, Chicago,
 Illinois,  12  p.   2  fig,  8 tab,  6  ref.

 Descriptors:   Subsurface drains,  Subsurface  drainage,  Water table,  Drawdown,
 Hydraulic  conductivity,  Porosity,  Discharge  measurement, Soil texture,  Design,
 Statistical methods.

 Hydraulic  conductivity and  drainable porosity were determined from water table
 drawdown and  outflow measurements  for  six fine-textured soils in  Ohio.   Drain
 spacings were computed for  three  drawdown rates  with a coefficient of  variation
 of about 30%.   When drawdown was  corrected for evapotranspiration,  spacings were
 reduced about 16%.


 78:048-010
 RESEARCH INTO THE EFFECTS OF ARTIFICIAL GROUNDWATER  RECHARGE,  LEA VALLEY,
 LONDON,ENGLAND,
 Edworthy,  K.J.,  Stott, D.A., and Wilkinson,  W.B.
 Water Research Centre, Medmenham,  England, Resources Division.
 Water Resources  Bulletin, Vol.  14,  No. 3,  p  554-575,  June,  1978.   11 fig, 2 tab,
 9  ref.

 Descriptors:   *Groundwater,  *Artificial recharge, *Recharge wells, *Lea  Valley
 (England),  *London  Basin (England),  Aquifers,  Chalk,  Sands,  Wells, On-site
 investigations.

 Large-scale groundwater  abstraction from  the Cretaceous Chalk/Lower Tertiary
 Basal Sands aquifer system  of  the  London Basin in the  last  150  years has devel-
 oped  storage  of  more  than 1,000,000 cu m.  Limited operational  recharge  was
 undertaken in  the 1950's encouraging further detailed  study of  the wider possi-
 bilities.   Following  a comprehensive hydrogeological  reappraisal, an economic
 and engineering  study, and  pilot-scale experiments,  the Lea Valley was shown to
 have  the greatest potential for recharge.  Artificial  recharge  into the  Chalk at
 a  rate  of  9,000  cu  m/d appears  possible, through acidized 900 mm  diameter bore-
 holes.  An understanding of the degree of interconnection between the Chalk and
 Basal Sands and  of  the causes of changes in  quality  of recharge water during
 storage was shown to  be  of  particular importance to  the successful operation of
 any recharge  scheme using this  system.  A two-layer numerical groundwater model
 of  the  800  sq  km area and a surface/groundwater simulation model  was used to
 assist with the  design of the  84,000 cu m/d  prototype  scheme, and also will help
 in  assessing  its efficiency.  The models ultimately will be  used  to manage the
 operation  of the first stage development, now coming into use.


 78:048-011
 THREE-DIMENSIONAL MODELING  OF GROUNDWATER FLOW SYSTEMS,
 Frind, E.G., and Verge,  M.J.
 Waterloo University,  Waterloo,  Ontario, Canada N2L 3G1, Department of Earth
 Sciences.
 Water Resources  Research, Vol.  14,  No. 5, p  844-856, October, 1978.  15  fig, 3
 tab,  30 ref, 15  equ,  1 append.

 Descriptors:   Groundwater movement, Model studies, Finite element analysis,
 Continuity  equation,  Saturated  flow, Unsaturated flow, Groundwater basins, Cost
 analysis, Feasibility studies,  Computer models.

 Practical aspects of  three-dimensional (3-D) modeling of groundwater flow systems
were  closely examined.   A Galerkin  finite element model was designed with a view
 to providing flexibility, user  convenience,  and a high degree of efficiency,
qualities which  are critical to the success  of 3-D modeling of real systems.  The
model was based  on  the general  saturated-unsaturated continuity equation.  Sev-
eral  integration schemes and matrix solvers were compared,  and relative costs were
expressed as functions of grid  size.  Examples presented include a hypothetical


                                     165

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system and a real system.  Simulation costs were generally found to be reasonable
for grids' of the size encountered with real systems.  It was found that the
remaining obstacle to the unified treatment of saturated-unsaturated systems was
that the optimum element sizes required for saturated and unsaturated flow were
not always compatible because of constraints arising from the physical properties
of the materials.  In general, however, it appeared that with presently available
tools, 3-D analysis is a practical option.


78:046-012
FINITE ELEMENT METHOD FOR SUBSURFACE HYDROLOGY USING A MIXED EXPLICIT-IMPLICIT
SCHEME,
Narasimhan, T.N., Neuman, S.P., and Witherspoon, P.A.
California University, Berkeley, Lawrence Berkeley Laboratory.
Water Resources Research, Vol. 14, No. 5, p 863-877, October, 1978.  19.fig, 2
tab, 32 ref, 38 equ, 2 append.

Descriptors:  Subsurface flow, Finite element analysis, Model studies, Computer
programs, Groundwater movement, Aquifer management, Infiltration, Drainage,
Saturated flow, Unsaturated flow.

The mixed explicit-implicit Galerkin finite element method developed previously
by the authors was shown to be ideally suited for a wide class of problems
arising in subsurface hydrology.  These problems include confined saturated
flow, unconfined flow under free surface conditions subject to the Dupuit
assumption, flow in aquifers which are partly confined and partly unconfined,
axisymmetric flow to a well with storage, and flow in saturated-unsaturated
soils.  A single computer program, entitled Flump, can handle all of these
problems.  The"mixed explicit-implicit solution strategy employed in the program
insured a high level of accuracy and computation efficiency in most cases.  Some
of the outstanding features of this solution strategy included an automatic
control of time step size,  reclassification of nodes from explicit to implicit
during execution, automatic adjustment of the implicit time-weighting factor,
and the treatment of boundary conditions and source terms as arbitrary functions
of time of the state of the system.   Five examples were presented to demonstrate
the versatility and power of this new approach.  A purely physical derivation of
the finite element equations which does not rely on the Galerkin formalism was
also included in one of the appendices.


78:046-013
USE OF BOUNDING WELLS TO COUNTERACT THE EFFECTS OF PREEXISTING GROUNDWATER
MOVEMENT,
Whitehead, W.R., and Langhetee, E.J.
Louisiana State University, Baton Rouge, Department of Petroleum Engineering.
Water Resources Research, Vol. 14, No. 2, p 273-280, April, 1978.  8 fig, 5 ref.

Descriptors:  *Salaquifers, * Bounding wells, *Water storage, *Injection wells,
*Underground storage/ Groundwater movement, Potentiometric level, Least squares
method, Computer programs.

Underground storage of freshwater in salaquifers is feasible under natural or
man-made conditions.  Since recovery efficiency is inversely proportional to
the rate of groundwater flow, reducing the potentiometric gradient reduces
fresh-water loss.  This can be done by installing injection and producing
bounding wells.  A desired balanced potentiometric level was selected, then the
required rates of the bounding wells were computed using a Fortran IV computer
program which employed a least squares solution.  The results of the computer
runs indicated that bounding well flow rates vary directly with the magnitude
of groundwater movement, inversely with the number of bounding well, and
directly with the distance the wells are placed from the boundaries.  The only
limitations are that the distance should not be less than 30 degrees of the
radius of the storage area, there should be at least one bounding well in each
quadrant of the storage area, and the sum of the production rates must equal
the sum of the injection rates.  The latter limitation ensures that the environ-
mental impact of the system is negligible.  A cost comparison chart indicated
that the in-place water cost at which a bounding well system will become economi-
cally attractive decreases as the volume stored increases.
                                     166

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78:048-014
SHOULD INTEGRATE PEAK LOAD WITH WATER MANAGEMENT,
Irrigation Age, Management.
Irrigation Age, Vol. 13, No. 1, p 64, September, 1978.  1 fig.

Descriptors:  Irrigation practices, Irrigation efficiency, Pumping, Energy,
Sprinkler irrigation, Water reuse, Center pivot systems, Water pressure, Farm
equipment, Fertilizers.

Center pivot irrigators who rely on electricity could save up to $72 million a
year if more "integrated" peak electrical load and water management control
systems were designed.  And, the technical knowledge is available.  At the same
time, power suppliers would be able to more successfully deal with the problems
of high peak electrical demands.  The problem is that short term peaks require
generation and transmission facilities that are under-utilized during much of
the year.  Key to success with an integrated approach is that irrigation scheduling
techniques, geared to saving both water and energy, would be used.  Savings in
nitrogen, pumping costs and system wear could amount to another $60 million
annually with better water management.
                                     167

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                                  SECTION XVIII


                    WATER QUANTITY MANAGEMENT AND CONTROL

          EFFECT ON WATER OF MAN'S NONWATER ACTIVITIES (GROUP 04C)


78:04C-001
TO SOLVE HIGHWAY AND FARM WATER MANAGEMENT PROBLEMS,
Smith, R.L., and Drablos, C.J.W.
Illinois University, Urbana, Department of Agricultural Engineering.
Agricultural Engineering, Vol. 59, No. 2, p 22-24, February, 1978.  4 fig.

Descriptors:  Highway effects. Drainage, Drainage water, Soil erosion, Sedimenta-
tion, Legal aspects, Soil conservation. Water management (applied).

Wherever agricultural lands are crossed by highways, drainage interrelationships
between the highway authorities and the adjoining landowners become complex.
Engineering and legal judgment plays an important role in finding the satisfac-
tory solutions to these problems.  While it may be permissible to temporarily
obstruct local highways with ponded water, eroded material, and debris, such
conditions should not permanently exist on highways which are subject to heavy,
high-speed traffic.  And care must be exercised to reduce adverse effects on
adjoining lands as a result of the highway facilities—for example, the diversion
of water from natural water courses, the interception of subsurface drainage
systems, the obstruction of the natural water flow.  This paper discusses the
various aspects of these problems and suggests how the magnitude of most problems
can be reduced which will cause least disruption.


78:04C-002
DRAINAGE PRACTICE IN IMPERIAL VALLEY,
Hermsmeier, L.F.
Imperial Valley Conservation Research Center, United States Department of
Agriculture-Agricultural Research Service, Brawley, California.
Transactions of the American Society of Agricultural Engineers, Special Edition,
Vol. 21SW, No. 1, p 105-109, February 20, 1978.  1 fig, 7 tab, 10 ref.
(See 78:03C-006)
                                     168

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                                     SECTION XIX


                        WATER QUANTITY MANAGEMENT AND CONTROL

                          WATERSHED PROTECTION  (GROUP 04D)


78:040-001
EROSIONAL REMOVAL OF FALLOUT PLUTONIUM FROM A LARGE MIDWESTERN WATERSHED,
Sprugel, D.G., and Bartelt, G.E.
A  onne National Laboratory, Illinois, Radiological and Environmental Research
Division.
Journal of Environmental Quality, Vol. 7, No. 2, p 175-177, April-June, 1978.
2 tab, 28 ref.

Descriptors:  *Erosion, *Sediments, *Plutonium, Watersheds (basins), Sampling,
Data processing, Sediment transport, Sorption, Soils, Soil erosion, Suspended
solids.

The Great Miami River at Sidney, Ohio, drains a 1,401-sq km watershed which is
generally flat and predominantly agricultural.  Samples of river water
collected over a wide range of flow and sediment loading conditions showed that
the concentrations of 239, 240 Pu in filtered water and suspended sediment were
fairly constant, which means of 0.15 fCi/liter for water and 14 fCi/g for suspended
sediment.  Plutonium concentrations in suspended sediment are somewhat higher than
plow-layer soil concentrations, probably due to settling of larger soil particles
in ponds and backwaters in the upper reaches of the river.  Annual plutonium
transport from the watershed by erosion averages 1.2 mCi, or 0.9 pCi/sq m, which
is about 0.05% of the total plutonium in the watershed soil.   The primary mechanism
for plutonium removal is erosion of small soil particles to which the element is
sorbed.


78:040-002
EROSIONAL TRANSPORT AND DEPOSITION OF PLUTONIUM AND CESIUM IN TWO SMALL MIDWESTERN
WATERSHEDS,
Muller, R.N., Sprugel, D.S., and Kohn, B.
Argonne National Laboratory, Illinois, Radiological and Environmental Research
Division.
Journal of Environmental Quality, Vol. 7, No. 2, p 171-174, April-June, 1978.
4 fig, 1 tab, 18 ref.

Descriptors:  *Sediment transport, *Sediment sorting, *Particle size, On-site
investigations, Sediments, Radioisotopes, Plutonium,  Cesium,  Soils, Clays,

The soils and sediments of two small watersheds and their retaining ponds were
sampled in a study of the erosional transport of plutonium and cesium in mid-
western ecosystems.  In a watershed which had been used exclusively for row crops,
no relationship was observed between plutonium content of the sediments and location
in the pond or clay content.  In a pasture watershed, sorting of the eroded material
had occurred prior to entry into the pond and also withia the pond.  Clay content
in the pasture pond sediments was significantly higher than in the soils of the
surrounding watershed and increased with increasing distance from the inlet.
Plutonium concentration in the sediments was strongly correlated with clay content,
reflecting the higher plutonium content of finer soil particles.  Cesium behaved
similarly to plutonium in the soils and sediments of  both watersheds.  Where sort-
ing occurs, as in the pasture watershed, deposits of  fine sediments will contain
higher plutonium and cesiumiconcentrations than in the original surface soil.


78:04D-003
TRANSPORT OF AGRICULTURAL CHEMICALS FROM SMALL UPLAND PIEDMONT WATERSHEDS,
Smith, C.N., Leonard, R.A.,  Langdale,  G.W., and Bailey,  G.W.
Environmental Research Laboratory, Athens, Georgia  30605 and Southern Piedmont
Conservation Research Center, Watkinsville, Georgia  30677.
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 Publication No.  EPA-600/3-78-056,  May,  1978.   364  p,  96  fig,  177  tab,  41  ref,
 8 append.

 Descriptors:   Herbicides,  Fertilizers,  Pesticides,  Surface water  runoff.

 Data were  collected from four  small watersheds  (1.3 to 2.7 ha)  located  in the
 Southern Piedmont region.   Two watersheds were  managed without  conservation
 measures;  the other two watersheds were parallel-terraced and included  grassed
 waterways  for soil erosion control.   Total  losses  of  applied  herbicides were
 affected by the  occurrence of  runoff  in close proximity  to application  date,
 mode of  application,  and persistence  in the soil runoff  zone.   Most of  the
 total annual  losses by  runoff  were in the first three runoff  events for all
 compounds  except paraquat.   Runoff of trifluralin was very low  {0.1 to  0.3% of
 the  annual application).   Total runoff  losses of other herbicides were  commonly
 less than  1.0% except when runoff  occurred  shortly  after application.   Sediment
 yield from terraced watersheds was significantly less than from watersheds
 managed  without  terraces.   Except  for paraquat, however, pesticide yields in
 runoff were not  reduced in proportion to sediment  reduction because solution
 transport  was the major mode of loss  for the soluble  herbicide  phase.   Annual
 runoff losses of soluble plant nutrients were 5.0  and 1.3 kg/ha for chloride
 and  nitrate,  respectively.   Losses of soluble phosphorus from both watersheds
 were very  low, about  380 g/ha.


 78:040-004
 EFFECT OF  MULCHING ON SEDIMENT IN  RUNOFF FROM SIMULATED  RAINFALL,
 singer,  M.J.,  and Blackard,  J.
 California University,  Davis,  Department of Land, Air, and Water Resources.
 Soil Science  Society  of America Journal, Vol. 42, No. 3, p 481-486, May-June,
 1978.  2 fig,  2  tab,  22 ref.

 Descriptors:   *Erosion  control, *Mulching,  *Simulated rainfall, Laboratory tests,
 Erosion, Soil erosion,  Litter,  Leaves,  Data processing,  Sediments.

 Simulated  rainfall was  used  to test the relationship  between  sediment in  runoff
 and  percent of the soil  that was mulch  covered.  Oak  leaves,  redwood litter, and
 oat  straw  were used as  mulches  on  a 0.37 sq m plot  of Auburn  (loamy, mixed,
 thermic, Ruptic-Lithic  Xerochrepts) surface soil at a 9% slope.  Cover percentage
 was  related to sediment  in surface runoff by a parabolic relationship.  The
 relationship  between  redwood and oak  covers and sediment in runoff was not
 significantly different, but both were  significantly  different  from oat straw.
-Cover  shape or distribution  of  inter-cover  space appears to be  important  in
 affecting  sediment loss.   Runoff volume was reduced significantly by high cover
 levels which  protected  the soil from  sealing and helped maintain a high infiltra-
 tion rate.


 78:040-005
 A SEDIMENT  GRAPH MODEL BASED ON AN INSTANTANEOUS UNIT SEDIMENT GRAPH,
 Williams,  J.R.
 Agricultural  Research Service, Temple, Texas, Grassland Forage Research Center.
 Water  Resources  Research, Vol.  14, No.  4, p 659-664, August,  1978.  2 fig, 3 tab,
 10 ref.

 Descriptors:   *Sedimentation rates, *Erosion, *Texas,  *Storm runoff, -*Model studies*
 Mathematical models, Sediments, Rainfall, Watersheds  (basins), Land use.

 A model was developed for predicting  sediment graphs  from agricultural watersheds.
 Storm sediment graphs were predicted by convolving  source runoff with an  instan-
 taneous unit sediment graph  (IUSG).  The IUSG is the distribution of sediment from
 an instantaneous burst of rainfall producing one unit of runoff.  The IUSG is the
 product of   an instantaneous unit hydrograph and the sediment concentration dis-
 tribution.   Initial sediment concentration of IUSG was assumed to vary linearly
with source runoff volume.  A sediment-routing function,  based on travel time and
 sediment particle  size,  was used to predict the sediment concentration distribution.
Tests with  50 storms from 5 watersheds showed that the model is applicable to
 agricultural watersheds  in the Texas blacklands.  It should be useful  in designing
 reservoirs  or in water quality-modeling problems.
                                      170

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 78:040-006
 FAILURE SEQUENCE OF GULLY HEADWALLS IN WESTERN IOWA,
 Bradford, J.M., Piest, R.F. , and Sportier, R.G.
 Missouri Agricultural Experimental Station,.Columbia.
 Soil Science Society of America Journal, Vol. 42, No. 2, p 323-328, March, 1978
 6 fig, 1 tab, 20 ref.

 Descriptors:  *Erosion, *Iowa, *Missouri, *South Carolina, *Soil morphology,
 Soil strength, Sedimentation, Slope stability, Gully erosion, Loess.

 A characterization of the failure sequence of gully headwalls and banks is
 necessary to predict gully erosion rates and to develop controls.  A model was
 given for the sequential nature of gully growth in the thick loessial area of
 western Iowa.  The failure sequence includes a popout or alcove failure near the
 toe of a near-vertical wall; columnar sloughing of the overhanging material;
 and finally, the transport of the eroded material downstream.  The initiating
 failure at the base of the wall is a result of weakening of the soil material
 by wetting.   The gully bank failure sequence and geometry in the western Iowa
 loess region were compared to gully erosion studies in the glacial drift region
 of northwestern Missouri and in the Piedmont of South Carolina.


 78:040-007
 CONTROLLING  DUST IN THE MOHAVE VALLEY,
 Halderman, A.D.
 Arizona Agricultural Experiment Station,  Tucson.
 Agricultural Engineering,  Vol.  59,  No.  2,  p 25-26,  February,  1978.

 Descriptors:  *Soil management,  *Dust,  *Air pollution,  *Wind  erosion,  *Arizona,
 *Colorado  River,  *Mohave Valley  (Arizona)',  Soil erosion,  Land reclamation,  Grading.

 Land grading to  adapt Indian lands  for  irrigated  farming  along the  Colorado River
 in Mohave  County, Arizona,  has  created  dust problems  severe enough  to  close
 schools  and  alarm health authorities.   Between the  removal of vegetation and  the
 establishment of a  crop, the land is particularly vulnerable  to blowing.  Members
 of the  University of  Arizona Department of  Soils, Water and Engineering have
 offered  several recommendations  to  alleviate the  problem:  Limiting the amount
 of land  graded at any  one  time,  coordinating clearing operations with  prevailing
 winds to avoid blowing  toward urban and commercial  centers, digging wells to wet
 the  land after brush  removal and before grading,  and the  establishment of crops
 as soon as possible after grading.  These recommendations can be adapted to local
 conditions and are presently being  implemented.


 78:040-008
 MAXIMUM NONEROSIVE FURROW IRRIGATION STREAM  SIZE,
 Hamad, S.N., and Stringham,  G.E.
 Utah State University, Logan, Department of  Agricultural and Irrigation Engineering.
 Journal of the Irrigation and Drainage Division, American Society of Civil
 Engineers, Vol. 104, No. IR3, Proceedings Paper 14021, p 275-281, September,
 1978.  3 fig, 1 tab, 13 ref,  2 append.

 Descriptors:   *Furrow irrigation, *Erosion,  *Irrigation ditches,  Size, Slopes,
 Slope stability, Channels,  Channel erosion. Channel flow, Irrigation, Surface
 irrigation, Soils, Water pollution, Sediments.

A technique was presented to predict maximum nonerosive irrigation stream size for
 furrows as a function of soil type and bed slope.  Data for different soils and
 field conditions were analyzed to estimate the coefficients of a  prediction equa-
tion.  A table giving the estimated coefficients for each soil type was given.
                                     171

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                                  SECTION  XX


                    WATER QUALITY MANAGEMENT AND PROTECTION

                   IDENTIFICATION OF POLLUTANTS (GROUP 05A)


78:05A-001
IMPACT OF LAND USE ON GROUNDWATER QUALITY IN THE GRAND TRAVERSE BAY REGION OF
MICHIGAN,
Rajagopal, R.
Duke University, Durham, North Carolina, School of Forestry and Environmental
Studies.
Journal of Environmental Quality, Vol. 7, No. 1, p 93-98, January-March, 1978.
6 fig, 5 tab, 17 ref.

Descriptors:  *Groundwater, *Water quality, *Land use, *Michigan, *Grand
Traverse Bay Region  (Michigan), Surveys, Sampling, Pollutants, Water pollution,
Path of pollutants.

Investigations in townships surrounding the Grand Traverse Bay of Michigan
showed an identifiable geographic relationship between groundwater quality and
land use.  Wells averaging 32 m deep in thinly populated areas measured an
average of 3.75 ppm nitrate-N, indicating the effect of prolonged years of
fertilizer application.  Wells averaging 19 m deep in predominantly residential
areas had an average of 1.31 ppm nitrate-N, indicating possible contamination
from septic tank effluents.  An average of 0.18 ppm of ammonia-N was detected in
marshy wetlands.  An analysis of temporal variations in groundwater quality with
reference to precipitation, streamflow, and a trend component provided high as
well as low R sq (0.92 to 0.12;R sq = square of the multiple correlation coeffi-
cient) producing regression models, indicating the'effect of site specific con-
ditions.  A year-long observation of a sample well (43 m deep) surrounded by
cherry orchards has an average of 18.25 ppm nitrate-N in a range of 13.09 to
20.64 ppm, almost double the standard considered safe for human consumption.
Ammonia-N and chloride measurements from a shallow well  (12.5 m deep), sur-
rounded by residential and commercial activities, showed synchronized variations
over a year (correlation coefficient r = 0.75, significant at 1% level), sug-
gesting the existence of a common source of contamination.  In summary, it was
reiterated that the analysis of groundwater quality problems requires a differ-
ent philosophical approach from the approaches used for water quantity and
surface water quality modeling.


78:05A-002
ARSENIC POLLUTION FROM UNDERDRAINAGE AND RUNOFF FROM GOLF GREENS,
Duble, R.L., Thomas, J.C., and Brown, K.W.
Texas A & M University, College Station, Department of Soil and Crop Sciences.
Agronomy Journal, Vol. 70, No. 1, p 71-74, January-February, 1978.  4 fig, 6 ref.

Descriptors:  Golf courses, Arsenicals (pesticides), Pollutants, Leachate,
Runoff, Return flows, Sprinkler irrigation, Turf grasses.

A field study was conducted using four lysimeters (each 3 m by 3 m) containing a
Tabor sandy loam soil  (Udertic Paleustales) and 16 lysimeters containing differ-
ent sand-soil-peat mixtures, each equipped with a gravel underdrainage system.
Bermudagrass (Cynodon dactylan L.) turf was maintained at a height of approxi-
mately 1 cm of water daily.  Tricalcium arsenate was applied on two dates at a
rate of 88 kg ha"1.  Arsenic was found in significant concentrations in both
drainage and runoff from lysimeters.  Particularly high concentration  (8 ppm As)
were found in the drainage from plots previously cored for soil samples.  Con-
centrations of As in the runoff were as great as 14 ppm when a heavy rain
occurred shortly after application of Ca3(As04)2.  Drainage from the plots
                                     172

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 typically  contained  1  to  3  ppm and  decreased  slowly with  time.  Arsenic  concen-
 trations of  0.8  ppm  were  still found  in  the drainage  115  days after  application.
 Concentrations of  As in the runoff  and drainage  from  all  the plots exceeded
 acceptable limits  for  irrigation water established by the U.S. Public  Health
 Service.


 78:05A-003
 ATRAZINE MOBILITY  IN TWO  SOILS UNDER  CONVENTIONAL TILLAGE,
 Hall, J.K.,  and  Hartwig,  N.L.
 Pennsylvania Agricultural Experiment  Station, University  Park, Soil  Chemistry
 and Weed Science.
 Journal of Environmental  Quality, Vol. 7, No. 1, p 63-68,  January-March,  1978..
 7  tab, 20  ref.

 Descriptors:  Pesticides, Herbicides, Leaching, Lysimeters, Bioassay,  Soil
 contamination, Pennsylvania.

 Atrazine mobility  was  studied  in two  different Pennsylvania soils under  conven-
 tional tillage.  Atrazine mobility,-dissipation rate,  and residual activity were
 evaluated  by chemical  analysis and  oat bioassay of soil cores sampled  at 15-cm
 increments to 122  cm and  from  chemical analysis of suction lysimeter leachates.
 It appeared  from this  study that application  of atrazine  to fine-textured, con-
 ventionally  tilled soils  at rates ranging from-1.0 to 4.5 kg/ha would  not seriously
 affect groundwater supplies through contamination by  internal soil damage.


 78:05A-004
 NITRATE ACCUMULATION IN SOILS  AND LOSS IN TILE DRAINAGE FOLLOWING NITROGEN
 APPLICATIONS TO  CONTINUOUS  CORN,
 Cast, R.G.,  Nelson,  W.W., and  Randall, G.W.
 Minnesota  University,  St. Paul, Minnesota Agricultural Experiment Station.
 Journal of Environmental  Quality, Vol. 7, No. 2, p 258-261, April-June,  1978.
 1  fig, 4 tab, 9  ref.

 Descriptors:  Nutrient removal, Denitrification, Nitrates, Tile drainage, Water
 pollution, Sweet corn, Minnesota.

 Nitrate-N  concentration in  tile water, loss from tile  lines, and accumulation  in
 soil profiles were determined  following each of three annual applications of 20,
 112, 224,  and 448  kg N/ha to continuous corn  (Zea mays L.) grown on a Webster
 clay loam  (Typic Haplaguoll) in southern Minnesota.   Plots were isolated to a
 depth of 1.8 m with  plastic to allow an accurate assessment of the area drained.
 There was  relatively little increased N03-N accumulation  in the soil profile or
 loss from  tile lines at the recommended application rate  of 112 kg N/ha compared
 to that for the  check  treatment.  Nitrate-N losses through tile lines in 1975
 (after 3 years treatment)  were  19, 25, 59, and 120 kg/ha  for the 20,  112, 224,
 and 448 kg N/ha  applications,  respectively, which had N03-N accumulations in the
 0-3 m soil profiles  of 54,  100, 426, and 770 kg N03-N/ha.  Maximum N03-N accumu-
 lation in  the soil profiles occurred at a depth of about  1 m with little evidence
 of movement below  about 2.2 m.


 78:05A-005
 EFFECTS OF TRACE ELEMENTS ON NITRIFICATION IN SOILS,
 Liang, C.N.,  and Tabatabai,  M.A.
 Iowa State University, Ames, Department of Agronomy.
 Journal of Environmental Quality, Vol. 7, No.  2, p 291-293, April-June, 1978.
 3 tab, 15  ref.

 Descriptors:   Nitrification, Inhibitors,  Nitrates,  Nitrites,  Trace elements,
Heavy metals, Pollutants.

Studies to evaluate the effects on nitrification of 19 trace elements showed that
all these elements inhibited nitrification of NH4(+)-N added to soils.   Results
 showed that the relative effectiveness of the trace elements in inhibition of
nitrification depends on the soils.   When the trace elements were compared to
using 5 micromoles/g of soil, Ag(I), Hg{II),  Cd(II),  Ni (II),  As(III), Cr(III),
                                        173

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B(III), Al(III), Se(IV), and Mo(VI) were the most effective  inhibitors  (average
inhibition  >50%, and Mn(II) and Pb(II) the  least effective  (average inhibition
<25%)  inhibitors.  The average inhibition by the elements Co(II), Cu(II),
Sn(II), Fe(II), Zn(II), Fe(III), V(IV), and W(VI) ranged from  33% with W(VI) to
49% with Fe(III).  Silver(I), Ni(II),  Co(II), Zn(II), Mn(II),  Pb(II), As(III),
B(III), Fe(III), As(V), Mo(VI), and W(VI) inhibited Nitrobacter, causing accumu-
lation of N02(-)-N in one of the soils used.


78:05A-006
A METHOD FOR PARAMETER SENSITIVITY ANALYSIS IN DIFFERENTIAL  EQUATION MODELS,
Kohberger,  R.C., Scavia, D., and Wilkinson, J.W.
Albany Medical College, New York, Division  of Computer Science.
Water  Resources Research, Vol. 14, No. 1, p 25-29, February, 1978.  4 fig, 4
tab, 13 ref, 9 equ.

Descriptors:  Mathematical models, Least squares method, Analytical techniques,
Probability.

A numeric method for analyzing global  parameter sensitivity  about a fixed point
in parameter space for differential equation models is presented.  The method is
suitable for large-scale, multiresponse systems which may not  be in steady
state.  By  using a quadratic model, the relationship between several global
response characteristics and parameter perturbations is examined.  Sensitivity
relationships are defined with both backward elimination regression model selec-
tion procedures and eigenvalue-eigenvector  analyses.  An example of the method
is given using an ecosystem model consisting of 14 coupled differential equa-
tions.


78:05A-007
DESIGN CONSIDERATIONS FOR AMBIENT STREAM QUALITY MONITORING,
Lettenmaier, D.P.
Washington  University, Seattle, Department  of Civil Engineering.
Water  Resources Bulletin, Vol. 14, No. 4, p 884-902, August, 1978.  3 fig, 5
tab, 21 ref.

Descriptors:  *Monitoring, *Water quality,  *Network design,  *Mathematical
models, Networks, Sampling, Streams, Pollutants, Statistics, Statistical models.

Existing ambient water quality monitoring programs have resulted in data which
are often unsuitable for assessment of water quality trends.  A primary concern
in designing a stream quality monitoring network is the selection of a temporal
sampling strategy.  It is extremely important that data for  trend assessment be
collected uniformly in time.   Greatly  superior trend detection power results for
such a strategy as compared to stratified sampling strategies.  In general, it
is desirable that sampling frequencies be at least monthly but not greater than
biweekly; higher sampling frequencies  usually result in little additional infor-
mation.  An upper limit on trend detectability exists such that for both five
and ten year base periods it is often  impossible to detect trends in time series
where  the ratio of the trend magnitude to time series standard deviation is less
than about  0.5.  For the same record lengths, trends in records with trend to
standard deviation ratios greater than about one usually can be detected with
very high power when a uniform sampling strategy is followed.


78:05A-008
SAMPLING FREQUENCY FOR RIVER QUALITY MONITORING,
Sanders,  T.G.,  and Adrian, D.D.
Colorado State University, Fort Collins,  Department of Civil Engineering.
Water  Resources Research, Vol. 14, No. 4, p 569-576, 1978.    5 fig, 3 tab, 25 ref.

Descriptors:  *Sampling,  *Monitoring,  *Water quality, *Connecticut River,
Control,  Water analysis,  Statistical methods, Chemical analysis, River basins,
River  flow.

Sampling frequency for a water quality monitoring network is presented, and for
illustrative purposes the criterion is applied to the Massachusetts portion of
the Connecticut River basin.   The proposed  frequency criterion is based upon the


                                     174

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  assumption  that  the  primary  objectives  of  future  river  quality monitoring  net-
  works  are the  determination  of  ambient  water  quality  conditions  and  an  assess-
  ment of yearly trends  rather than  detection, of  stream or effluent  standards
  violations.  The  sampling  frequency criterion is  derived as a function  of  the
  random variability of  the  river flow.   The  criterion  is specifically related to
  the magnitude  of  the expected half width of the confidence interval  of  the mean
  of the random  component of the  annual statistic--mean log river  flow.   The
  appropriate sampling intervals  (at each sampling  station within  the  river  basin)
  are determined by specifying equality of this confidence interval  half  width
  which  insures  a uniform reliability of  the  annual statistic.                '


  78:05A-009
  FIELD  MEASUREMENT OF DENITRIFICATION,
  Rolston, D.E., and Broadbent, F.E.
  California University, Davis, Department of Land, Air and Water  Resources
  Report No. EPA-600/2-77-233, November,  1977.  75 p, 40 fig, 15 tab,  13  ref.

  Descriptors:   *Denitrification,  *Soil moisture, *Vegetation effects, *Gas  flux,
  Irrigation,  Nitrates, Nitrites, Nitrogen compounds, Soil environment, Soil
 management.

 Denitrification from a Yolo loam field profile was studied in relation to the
 influence of soil-water content, organic carbon source,  and temperature.  Field
 plots were instrumented with soil atmosphere samplers, soil solution samplers,
 and tensiometers.  The two soil-water pressure treatments  were applied in top-
 soil.   Three levels of soil carbon were studied by evaluating plots cropped with
 ryegrass,  uncropped plots,  and plots  amended with manure.   Experiments were
 conducted at soil temperatures of 8 and 23C.  Fertilizer was  applied as KN03
 enriched-with N15.  The flux of volatile gases at the  soil  surface  was measured
 from the accumulation of N20 and nitrogen gas  isotopes beneath an airtight  cover
 placed  over  the soil  surface.  Denitrification at 23C  ranged  from 73% of the
 fertilizer nitrogen for the manure treatment to 1% for the  uncropped treatment.
 At 8C,  denitrification ranged from 11%  for the manure  treatment  to  zero for
 uncropped plots.   The nitrite flux at  the soil surface varied between 5  and 26%
 of total  denitrification.   The results  demonstrated that denitrification of soil
 can occur  at high rates (highest soon  after application  of  N03(-) fertilizer to
 wet soil), and  that  the presence of a  crop root  system has  a  large  positive
 influence  on denitrification.


 78:05A-010
 CARBON  CONTENTS AND SOURCES IN GROUNDWATERS  OF THE CENTRAL  PLATTE REGION IN
 NEBRASKA,
 Spalding,  R.F., Gormly, J.R.,  and Nash,  K.G.
 Nebraska University,  Lincoln,  Conservation  and Survey  Division.
 Journal of Environmental Quality, Vol.  7, No.  3, p 428-434, July-September, 1978.
 2 fig,  3 tab, 23  ref.

 Descriptors:  *Groundwater,  *Dissolved oxygen, *Dissolved organic carbon,
 *Carbon, *Nebraska, *Platte River (Nebraska),  *Alkalinity, Water  chemistry,
 Water wells, Land  use.

 Fifty-one groundwater samples  collected  in a losing reach of the  Platte  River
 were analyzed for  alkalinity,  dissolved  oxygen  (DO), and'dissolved  organic  carbon
 (DOC).  Ranges  in  concentrations were 24.8 to  109 mg/liter, .0 to 5.5 rag/liter,
 and 0.5 to 4.8  mg/liter for organic carbon,  DO, DOC, respectively.  The  concen-
 trations of these  constituents are primarily associated with land use and well
 depth.  Carbon  isotope  fractionation can be  useful in  determining sources of
 organic carbon  to  the groundwater.


 78:05A-011
AN IMPROVED SOIL-SAMPLING PROCEDURE FOR  THE PREDICTION OF DISSOLVED INORGANIC
PHOSPHATE CONCENTRATIONS IN SURFACE RUNOFF FROM PASTURE,
Sharpley, A.N., Syers, J.K., and Tillman, R.W.
Massey University, Palmerston North, New Zealand, Agricultural and Horticultural
Sciences.
                                     175

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Journal of Environmental Quality, Vol. 7, No. 3, p 455-456, 1978.
3 ref.
3 fig,  1 tab,
Descriptors:  *Phosphates, *Agricultural runoff, *Soil analysis, *Sampling,
*Phosphorus compounds, *Dissolved inorganic phosphates, *Phosphate transport,
*Soil sampling procedure, *Surface-runoff plots, Soil sampling.

Linear relationships were obtained between the mean concentration of dissolved
inorganic phosphate  (DIP) in each of several surface-runoff events and the
amounts of inorganic P extracted by 0.1M NaCl from the top 1 cm of soil sampled
prior to the event.  These relationships were similar for both unfertilized and
fertilized, undrained pasture.  This contrasted with the data obtained in the
previous year for the same surface-runoff plots, receiving the same treatments,
where markedly different linear relationships were obtained using a 0.5 cm soil-
sampling depth.  The modified soil-sampling procedure provides more generally
applicable method of predicting the concentration of DIP in surface runoff from
pastures of widely differing P status.


78:05A-012
PRECIPITATION AND THROUGHFALL CHEMISTRY IN THE SAN FRANCISCO BAY AREA,
McColl, J.G., and Bush, D.S.
California University, Berkeley, Department of Soils and Plant Nutrition.
Journal of Environmental Quality, Vol. 7, No. 3, p 352-357, July-September,
1978.  3 fig, 1 tab, 36 ref.

Descriptors:  Precipitation (atmospheric), Throughfall, Rainfall, Chemical
analysis, Forest soils, Air pollution, Nutrients, Acidity, California.

At Berkeley, California, main ionic constituents of bulk precipitation during
the wet season of 1974-1975 were S04(2-), Cl'(-) , HC03(-), Na(+) , and Ca(2+) ,
and mean H(+) concentration was 10.7 ± 1.5 microequivalents/liter (pH 5.0).
Although S04(2-) comprised 50% of the anions in bulk precipitation, H(+) con-
centration had the highest correlation with N03(-).  Impacted air pollutants
accumulated on tree leaves between major rainstorms.  Atmospheric N and S were
correlated with N03(-) and S04(2-) in bulk precipitation and leafwash in a
Eucalyptus globulus forest.  Ionic composition of bulk precipitation resembled
that of surface-soil solution in an adjoining, recently clear-cut area.


78:05A-013
METABOLISM OF NITROPHENOLS IN FLOODED SOILS,
Sudhakar-Barik, and Sethunathan, N.
Central Rice Research Institute, Cuttack-753006, India, Laboratory of Soil
Microbiology.
Journal of Environmental Quality, Vol. 7, No. 3, p 349-352, July-September,
1978.  4 tab, 12 ref.
(See 78:02K-049)


78:05A-014
BIOLOGICAL HYDROLYSIS OF PARATHION IN NATURAL ECOSYSTEMS,
Sudhakar-Barik, and Sethunathan, N.
Central Rice Research Institute, Cuttack-753006, India, Laboratory of Soil
Microbiology.
Journal of Environmental Quality, Vol. 7,-No. 3, p 346-348, July-September,
1978.  5 tab, 11 ref.
(See 78:02K-053)


78:05A-015
SOME PROPERTIES OF THE GEOMETRIC MEAN AND ITS USE IN HATER QUALITY STANDARDS,
Landwehr, J.M.
Geological Survey, Reston, Virginia, Water Resources Division.
Water Resources Research, Vol. 14, No. 3, p 467-473, June, 1978.  4 fig, 7 tab,
17 ref.
                                    176

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Descriptors:  *Water quality standards, *Coliforms, *Water analysis, *Analytical
techniques, *Statistical methods, *Swimming facilities, *Geometric mean, Proper-
ties, Sampling, Evaluation,

The geometric mean is often used to express acceptable levels of fecal coliform
counts in Federal and State water quality criteria or standards.  The expected
value of the geometric mean is shown to be a function of the sample size and to
be very sensitive to the skew as well as to the form of the underlying distri-
bution function.  Implications of these findings are discussed with regard to
standards.  In particular, it is noted that great care must be taken in specify-
ing the minimal sample size to be used.


78:05A-016
ESTIMATION AND MANAGEMENT  OF THE CONTRIBUTION BY MANURE FROM LIVESTOCK IN THE
ONTARIO GREAT LAKES BASIN  TO THE PHOSPHORUS LOADING OF THE GREAT LAKES,
Draper, D.W., Robinson, J.B., and Coote, D.R.                       ,_,„.,
Guelph University, Guelph, Ontario, Canada, Department of Environmental Biology.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p
159-174.   2 fig,  4 tab, 39 ref,  3 equ.

Descriptors:  Agricultural runoff. Nutrient removal, Phosphorus, Livestock, Great
Lakes, Water pollution, Water quality, Feed lots.

As part of the work of the International Reference Group on Great Lakes Pollution
from Land Use Activities  (PLUARG) a simple model has been developed for estimating
contributions of  total phosphorus to Great Lakes tributary loading originating
with  livestock manure produced  in the Basin.  Total loads attributable to live-
stock sources and a range  of probable unit loads on a per animal unit per year
basis were calculated.



PHOSPHORUS—A POTENTIAL NONPOINT SOURCE POLLUTION PROBLEM IN THE LAND AREAS
RECEIVING LONG-TERM APPLICATION OF WASTES,
Reddy, K.R., Khaleel, R. ,  Overcash, M.R. , and Westerman, P.W.
North Carolina  State University, Raleigh, Department of Biological and

P?oceedings1ofntheei9789Cornell Agricultural Waste Management conference, p 193-
211.  7  fig, 7  tab, 29 ref,  3 equ.

Descriptors:  Wastes, Phosphorus, Water quality, Runoff, Water  pollution sources,
Nutrients, Water  pollution.

The  main objective of this work was to describe  the P behavior  in the soils
treated  with wastes and  their relationship  to the  surface water quality.  The
resJlS  obtained  from these  studies indicated that application  of animal wastes
decreased P  sorption capacity of the  soil and increased P concentration in the
soil solution,  thus increasing  the equilibrium P concentration  (EPC) , at which
no net adsorption or desorption takes  place.  A  s*?f **C*"h ?J Js £ Scl T
observed between  EPC values  and P extracted with dilute acid  (0.05 N HC1 +
0.025 N  H2S04).   Continuous  application of wastes with high loading rates of P
resulted in P movement  into  deeper  layers.  Transport of ^^Jherinto deeper
soil layers  or  in the surface runoff water was dependent on the availability
or soluSle P in the soil  surface at  the  time of  rainfall event. Simple equations
were developed to describe the  availability of P at the soil surface, and the
processes controlling P  availability were  also  taken  into consideration.



ANIMAL'MANURE  MOVEMENT  IN WINTER RUNOFF  FOR DIFFERENT SURFACE CONDITIONS,
Thompson, D,B..  Loudon,  T.L., and Gerrish,  J.B.      _       *„„',, •*>-*„„
Minnesota University,  St.  Paul, Department of Agricultural  Engineering.
Proceedings of the  1978  Cornell Agricultural Waste Management Conference, p
145-157.   1 fig,  4  tab,  16 ref.

Descriptors:   Agricultural runoff,  Water quality,  Water pollution.  Nutrient
removal, Runoff,  Return flow, Water quality control.  Chemical oxygen demand,
Chemical degradation.
                                     177

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 This  experiment was  designed to observe  the impact of  selected  management
 practices  on winter  runoff  quality.   The effects  of various  surface  conditions
 and buffer zones on  runoff  quality  associated with land  application  of  animal
 waste on frozen,  snow-covered soil  were  evaluated.-  Three  different  surface
 covers with two lengths  of  buffer zone were compared as  management practices
 which could be  utilized  for the reduction of nutrients contained  in  runoff from
 land  application areas.   The surface  conditions used for the plots were corn
 stalk stubble with rows  running across the slope,  corn stalk stubble which had
 been  fall  disked across  the slope,  and established orchard grass.  Runoff
 samples were analyzed for concentrations of ammonia, total Kjeldahl  nitrogen,
 total phosphorus, chemical  oxygen demand (COD), total  and  volatile solids.
 Twelve plots were established on a  Hillsdale sandy loam  soil with a  3.5% slope.
 The plots  were  3  x 58 meters with the upslope 3 x 24 meters  receviing the
 manure application.   Four plots were  used for each surface conditions,  two control
 and two spread  with  62.7 M  ton/ha of  fresh dairy  manure.   The results of the
 experiment have been reported with  discussion.


 78:05A-019
 ESTIMATING PHOSPHORUS LOADING FROM  LIVESTOCK WASTES:   SOME WISCONSIN RESULTS,
 Moore,  I.e.,  Madison,  F.W.,  and Schneider,  R.R.
 Wisconsin  University,  Madison,  Water  Resources Center.
 Proceedings of  the 1978  Cornell Agricultural Waste Management Conference, p 175-
 192.   3 fig,  7  tab,  17 ref.

 Descriptors:  Wastes,  Water pollution. Water pollution control, Livestock, Water
 quality control,  Phosphorus,  Agricultural watersheds,  Pollutant identification,
 Agricultural  runoff,  Analytical techniques.

 A description of  an  approach used to  estimate phosphorus loading to  the Great
 Lakes  from livestock wastes  in Wisconsin was presented.  The  results reported
 represent  minimum annual loadings of  total phosphorus  to Lake Superior  and Lake
 Michigan from areas  of Wisconsin in these drainage basins.   Estimates of the
 total  phosphorus  reaching surface waters from manure sources  in the  rest of the
 state  were made on a per animal unit  basis.  The analytical  techniques  employed
 were  reported separately.   The emphasis  was placed on  the  data requirements of
 the analysis.   A  key assumption of the methodology is  that phosphorus in surface
 runoff  will be  linearly  attentuated as long as the overland  flow remains un-
 channelized.  Thus,  data on  the location of barnlots and manure-spread  fields
 with  relation to  surface features capable of channelizing  flow were  considered
 to  be  of primary  importance.   Problems encountered in  determining this distribu-
 tion of animal  concentrations with respect  to channels over a large  and physio-
 graphical  diverse region were  discussed.


 78:05A-020
 NUTRIENT AND  PESTICIDE MOVEMENT FROM  FIELD  TO STREAM:  A FIELD STUDY,
 Baker,  J.L.,  Johnson,  H.P.,  Borcherding,   M.A., and Payne, W.R.
 Iowa State University, Ames,  Department  of  Agricultural Engineering.
 Proceedings of  the 1978  Cornell  Agricultural Waste  Management Conference, p 213-
 245.   10 fig, 7 tab,  21  ref.

 Descriptors:  Nutrient removal,  Pesticide removal,  Agricultural runoff, Hydrologic
 aspects, Nitrogen, Phosphorus, Water  quality, Water pollution. Mathematical
 models, Sedimentation.

 The general .objective of  this  field study is to provide a better understanding of
 the relationships between management  farm systems  and  stream water quality and to
 enable  analysis of such  systems  using mathematical  models.   Specific objectives
 are (1)  to collect data  to refine an  Agricultural  Runoff Model proposed by U.S.
 Environmental Protection Agency; (2)  to  relate runoff  and soil-erosion nutrient
 {nitrogen  and phosphorus) losses to hydrologic factors as altered by land manage-
 ment;   (3)  to  relate  losses of pesticides   in  runoff  to pesticide properties and
 to hydrologic and management factors; and  (4) to relate sedimentation to hydrologic
 and management  factors.  In  this paper,   the  study was described and initial results
were presented.
                                     178

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 78:05A-021
 SEARCH  FOR  NITRIFYING  AGENTS  IN WATER AND  SOILS AS SOURCES OF NITRATES  IN
 SURFACE WATER,
 Phillips, N.A.,  and  Todd,  R.L.
 Georgia University,  Athens, Department of  Agronomy and  Institute of Ecology.
 Technical Completion Report,  USDI/OWRT Project No. A-066-GA, February,  1978.
 89 p, 9 tab,  61  ref, 1 append.

 Descriptors:  Nitrogen,  Nitrates, Surface  waters, Nitrification, Small watersheds,
 Forest  watersheds, Agriculture, Land  use.  Soil bacteria, Water quality.

 The  soil and  surrounding water of seventeen diverse types of watersheds were
 analyzed over a  one-year sampling period for a variety  of parameters.  Terrestrial
 nitrifying  populations were quantified.  Concentrations of ammonia, nitrate,
 and  total nitrogen and pH  were measured from soil extracts.  The water was
 analyzed for  concentrations of nitrate, ammonia, and seven'selected cations.  The
 terrestrial nitrifying bacteria were  found to be positively correlated to nitrate
 and  cation  loss  from so-called "natural" systems, i.e., ones that were not ferti-
 lized.  Those heavily  managed  (fertilized) systems showed no relationship bet-
 ween nitrate  and cation  discharge and numbers of nitrifying bacteria.  The average
 concentration of nitrate-nitrogen lost from natural systems was 0.07 mg/1 over
 the  year.   That  lost from  the fertilized systems averaged 0.47 mg/1, approximately
 a 7-fold increase.   Similiar relationships were found for average cation discharge.


 78:05A-022
 SOIL WATER  CONTENT AND TEMPERATURE AS FACTORS IN THE VOLATILE LOSS OF APPLIED
MERCURY (II)  FROM SOILS,
Landa, E.R.
Oregon  State  University, Corvallis, Departments of Soil Science and Agricultural
Chemistry.
Soil Science, Vol. 126,  No. 1, p 44-48, July, 1978. .2 fig, 1 tab, 16 ref.

Descriptors:  Mercury, Volatility, Soil contamination, Moisture content, Soil
temperature,  Pollutants, Pollutant identification, Water pollution sources.

Five surface  soils from  southeastern Montana were studied to determine the effects
of soil water content  and  temperature on the volatile loss of applied divalent
inorganic mercury.  Soils were amended to  1 ppm Hg as 203 Hg-Hg(NO3)2.  The
water content studies  involved soil samples at room temperature (18-25CC), either
allowed to  air-dry or maintained near the  1/3-bar or the 80% saturated moisture
levels.   The  temperature studies involved samples at the 1/3-bar moisture level
maintained  at either 10°C, room temperature, or 35°C.   Residual Hg content was
monitored for 5-7 weeks.  Hg losses were higher at the 1/3-bar moisture content
than at air-dryness or 80% saturation.  At 35°C the initial Hg loss rate was
accelerated with respect to room temperature, while at 10°C,  losses were con-
siderably reduced.
                                     179

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                                         SECTION  XXI

                           WATER QUALITY MANAGEMENT AND PROTECTION

                           SOURCES AND FATE OF POLLUTION  (GROUP  05B)


 78:053-001
 NITROGEN FERTILIZER AND NITRATE CONCENTRATIONS IN TRIBUTARIES OF THE UPPER
 SANGAMON RIVER  IN ILLINOIS,
 Klepper, R.
 Washington University, St. Louis, Missouri, Center for the Biology of Natural
 Systems.
 Journal of Environmental Quality, Vol.  7, No. 1, p 13-22, January-March,
 1978.  1 fig, 9  tab,  12 ref, 1 append.

 Descriptors:  *Nitrates, *Water pollution, *Fertilizers, *Farm  management,
 *Illinois, Regression analysis, Drainage, Tributaries, Soybeans, Data
 collections.

 Cross section multiple regressions were  used to test the importance of nitrogen
 fertilizer use  for variations in the nitrate nitrogen concentrations in 16 small
 tributaries of  the Sangamon River in east central Illinois.  Data were collected
 and regressions were  run for two years,  1974 and 1975.  Nitrate nitrogen con-
 centrations in  the spring  of each year were regressed on estimated nitrogen
 fertilizer use  per hectare of watershed  in the previous crop or calendar year and
 on variables representing  other aspects  of agronomic practice and hydrologic
 features.  The  fertilizer  data were collected by surveying approximately 300
 farmers.  Nitrate nitrogen concentrations were measured at four-week intervals.
 The regression  results are not clear-cut but lend support to nitrogen fertilizer
 use as an important explanatory variable for varia-tions in nitrate nitrogen
 concentrations.


 78:058-002
 POLLUTANT CONTRIBUTIONS FROM IRRIGATION  SURFACE RETURN FLOWS,
 Miller, W.W., Guitjens, J.C., Mahannah,  C.N., and Joung, H.M.
 Max C. Fleischmann College of Agriculture, Reno, Nevada.
 Journal of Environmental Quality, Vol. 7, No. 1, p 35-40, January-March, 1978.
 2 fig, 5 tab, 10 ref.

 Descriptors:  Water pollution effects, *Water quality control,  *Water pollution
 sources, *Flood irrigation, *Nevada, *Return flow, Water sampling, On-site
 investigations, Surface-groundwater relationships, Oxidation.

 Four study/sites, located in the Carson  River Basin, Nevada, containing approxi-
 mately 500,000 acres  irrigated by surface flooding, were selected for a two-year
 investigation of causes and sources of irrigation surface return flow pollution
 and the interrelationships among pollution components.  Irrigation applications
 and surface return flows were metered, net applied water was computed, and
 volume of infiltrated water was determined, based on water sampling and 'laboratory
 analysis of DO,  BOD, TDS, NO3,  -N, TN, PO4-P, and TP.  Phosphate content was
 determined,  via the persulfate digestion method.  Filterable orthophosphate was
 determined by the ascorbic acid method.  Study conclusions suggest:  (1) BOD,
 arid to a less extent, P4-P, are identified as major pollutants; (2) significant
 decrease in DO is noted as water moves from head to tail; (3) diffuse subsurface
 return flows appear to be sources of certain pollutants for surface water;  and
 (4)  water quality differences may be attributed in part to changes in water
 quantities/  suggesting the need for further investigation.


 78:058-003
EFFECTS OF SOIL, COVER CROP,  AND NUTRIENT SOURCE ON AMOUNTS AND FORMS OF PHOSPHORUS
MOVEMENT UNDER SIMULATED RAINFALL CONDITIONS,
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 Reddy,\G.Y., McLean, E.O., Hoyt, G.D., and Logan, T.J.
 Ohio Agricultural Research and Development Center, Wooster.
 Journal of Environmental Quality, Vol. 7, No. 1,  p 50-54,  January-March, 1978.
 1 fig, 4 tab, 20 ref.

 Descriptors:  *Phosphorus, *Runoff, *Sediraents,  laboratory  tests, *Path of
 pollutants, Erosion, Soil erosion, Soils,  Leachate,  Chemical analysis.

 Three soils (Toledo silty clay, Rossmoyne silt loam,  and Wauseon sandy loam)
 in greenhouse microplots were treated with chemical,  chemical + straw, and
 manure sources of N, P, and K, were cropped or left bare,  and were subjected
 to simulated rainfall.  Phosphorus moving in runoff sediments, runoff solution,
 and leachate was measured.  Most P moved as a component of sediments.   Cropping
 decreased sediment and solution losses,  while manure  generally increased losses
 in both.   Most P moving in runoff solution was inorganic.  However,  except
 where percolation swept inorganic P downward without  reaction with the soil,
 most P moving in leachate was organic.  Fractionations of  soil P revealed
 that P treatments increased the HN4C1- and NH4F-extractable  fractions  markedly,
 had less  effect on the NaOH-extractable  fraction,  and had  still less  effect
 on the H2SO4-extractable and organic fractions.   All  phosphorus sources
 markedly  increased the equilibrium P concentrations (EPC)  of all soils.   Manure
 increased EPC more than the other sources in the  Rossmoyne and Wauseon soils.
 The tendency is for more sediment P to be lost from manure and for manure-
 treated soil to mobilize P into solution, make erosion control especially im-
 portant if much manure is to be applied  to soils  and  if eutrophication of
 surface waters is to be minimized.


 78:053-004
 SURVIVAL  AND MOVEMENT OF FECAL INDICATOR BACTERIA IN  SOIL  UNDER CONDITIONS  OF
 SATURATED FLOW,
 Hagedorn,  C.,  Hansen,  D.T.,  and Simonson, G.H.
 Oregon State University,  Corvallis,  Department of  Microbiology.
 Journal of Environmental Quality,  Vol. 7, No.  1,  p 55-59,  January-March,  1978.
 2  fig,  3  tab,  8  ref.

 Descriptors:   *Bioindicators,  *Septic  tanks,  *Soil disposal  fields, *Water
 pollution  sources,  *Sewage bacteria, Disposal, Soil contamination, Public health,
 Coliforms,  Bacteria.

 Antibiotic-resistant fecal bacteria were  used  to monitor the degree of movement
 and subsequent groundwater contamination  by  septic tank effluent discharged into
 a  drainfield  under  saturated  conditions.   Two pits of different depths were
 constructed to simulate drainfield beds,  and groundwater samples were removed
 during thirty-two day  sampling intervals  from  sampling wells installed at set
 distances  from each  inoculation pit.   The bacteria added to the deep pit were
 released into  a B2t  horizon which contained  a higher clay  content than the A
 horizon in which  the shallower pit was installed.  Streptomycin-resistant strains
 of  Escherichia coli  and Streptococcus  faecalis amended to each pit site moved in
 a  directional  manner,  required more time  to reach  sampling wells when inoculated
 into the deeper of the two pits, and moved relatively long distances when con-
 sidering that  the area where  the sites were located .had only  a 2% slope.
 Bacterial  numbers peaked  in the  sampling  wells in  association with major rainfall
 patterns and the  populations required  longer periods to peak  in the wells
 furthest from  the inoculation  pits.  The  results indicated that antibiotic-
 resistant bacteria eliminated  the problem of differentiating  between the
 amended bacteria  and those nonresistant strains already in the soil, and the
 potential is excellent  for including this  type of microbiological procedure
 for assessing  the suitability  of a soil site for septic tank  and waste water
 drainfield  installations.


 78:05B-005
VIRUS ADSORPTION BY FIVE SOILS,
Surge, W.D., and Enkiri, N.K.
Agricultural Research Service, Beltsville, Maryland,  Agricultural Environmental
Quality Institute.
Journal of Environmental Quality, Vol.  7, No. 1,  p 73-76, 1978.  4 fig, 3 tab,
14 ref.


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 Descriptors:   *Bacteriophage,  *Soil  types,  *Clay loam,  *Silts,  *Adsorption,
 Waste water  treatment,  Sands,  Loam,  Sodium  chloride,  Cation exchange.

 The  Freundlich isotherm was applied  to  the  adsorption kinetics  of phi  X-174
 bacteriophage  in  five soil types with varying  physical  and  chemical properties.
 Adsorption rates  of  6 ml  of the bacteriophage  were  observed in  6 g samples of
 Aastad clay  loam,  Kranzburg silt loam,  Palouse silt loam, Parshall silt  loam,
 and  Quincy loamy  sand.  The Freundlich  isotherm and adsorption  rate constants
 were calculated for  adsorption of  the virus by the  soil were also determined.
 The  Quincy soil with a pH of 7.2 showed no  adsorption of the virus, due
 possibly  to  its high organic content.   Bacteriophage  adsorption was represented
 as a function  of  the square root of  time.   The cation exchange  capacity, speci-
 fic  surface  area,  and organic  carbon content of the soil correlated with the
 virus adsorption  rates  of the  four remaining soils.   The influence of  pH was
 found to  be  significant in the adsorption of the virus  by the soil.


 78:05B-006
 TRANSPORT OF ATRAZINE AND SIMAZINE IN RUNOFF FROM CONVENTIONAL  AND NO-TILLAGE
 CORN,
 Triplett,  G.B., Jr.,  Conner, B.J., and  Edwards,  W.M.
 Ohio Agricultural  Research and Development  Center,  Wooster.
 Journal of Environmental  Quality,  Vol.  7, No.  1,  p  77-84, January-March, 1978.
 1 fig,  7  tab,  25  ref.

 Descriptors:   *Herbicides, *Runoff,  *Weed control,  *Farm management, Storm
 runoff, Rainfall,  Corn  (field), Precipitation  (atmospheric), Pollutants, Crops.

 On    0.4-  to 3.5-ha  watersheds, highest  concentrations  of atrazine (0.48 ppm)
 and  simazine (1.2  ppm)  were present  in  runoff  occurring soon after application
 and  declined rapidly for  later events.   Quantity of herbicides  transported
 increased  with  the amount of runoff  and  was inversely related to the length of
 time between application  and the runoff  event.   A maximum of 6% of the applied
 herbicide  was  transported from the field even  under the most favorable condi-
 tions, and the  average  for all watersheds was  less  than 2%.  Less runoff and
 herbicide  loss  occurred from areas planted to  no-tillage than to conventional
 corn.  In  a multiple  regression analysis of the  factors, the natural logarithm
 (In)   of days after application and a tillage X application rate interaction
 were useful in  predicting the  natural logarithm of herbicide concentration in
 runoff.  Factors from the multiple regression  analysis  used in ttiis study were
 important  in predicting concentration of atrazine and other pesticides when
 applied to data published by other workers.


 78:058-007
 PHOSPHATE  ADSORPTION-DESORPTION CHARACTERISTICS  OF SUSPENDED SEDIMENTS IN THE
 MAUMEE RIVER BASIN OF OHIO,
 Green, D.B.,  Logan, T.J.,  and  Smeck,  N.E.
 Ohio Agricultural  Research and Development Center, Wooster, Department of
 Agronomy.
 Journal of Environmental  Quality,  Vol.  7, No.   2, p 208-212, April-June, 1978.
 3 fig, 3 tab, 15 ref.

 Descriptors:   *Phosphates, *Eutrophication,  *Algae,  Ohio,  Water pollution,
 *Phosphorus compounds, Water properties, Calcite, Surface runoff,  Soil erosion.

 Phosphorus (P)  adsorption-desorption characteristics of Maumee River Basin
 suspended sediments were  compared with those of Basin soils and stream bottom
 sediments.  Suspended sediment contained more total P than either soils or
bottom sediments.   The  increase in total P over soils is attributed to enrich-
ment of P  in sediment by selective erosion of fine particles and adsorption of
P during fluvial transport.   The suspended sediment had higher adsorption maxima
 than Basin soils,  but lower than bottom sediments, and had lower adsorption
energies than either soils or bottom sediments.  Calcite content of the sus-
pended sediments was correlated positively with total P, EPC (equilibrium P
concentration), and P desorbed and negatively correlated with adsorption
energy, implying that, although calcite is a sink for P, the adsorption is weak
compared with other sites  for P adsorption such as hydrous oxides  of Fe and Al.
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  78:05B-008
  SEASONAL RUNOFF LOSSES  OF NITROGEN AND PHOSPHORUS  FROM MISSOURI  VALLEY  LOESS
  WATERSHEDS^,
  Alberts,  E.E.,  Schuman,  G.E.,  and  Burwell,  R.E.
  Journal  of Environmental Quality,  Vol.  7, No.  2, p 203-208, April-June   1978
  6  tab,  21 ref.                                                         '

  Descriptors:   *Phosphates,  *Nitrogen,  ^Missouri, *Iowa,  *Surface runoff,  *Water
  quality,  *Soil  erosion,  *Nutrient  removal,  Phosphorus  compounds, Sediments.

  Seasonal  losses of nitrogen and phosphorus  in  surface  runoff were determined
  for a seven-year period  from three  corn-cropped watersheds in southwestern
  Iowa.  Three seasonal periods were  defined:  fertilizer, seedbed, and esta-
  blishment period from April through June  (PI); reproduction and  maturation
  period from July through November  (P2); and residue period from  December  through
  March (P3).  Most of the average annual total  N and P  losses were associated
  with the  sediment portion of runoff and occurred during PI.  The extreme  sus-
  ceptibility of  the loess soils to erosion during PI must be taken into account
  when designing  conservation practices to control plants nutrient losses.
  Seasonal  discharges of runoff, sediment, and nutrients were much lower from a
  level-terraced  watershed than from  two contour-farmed watersheds, which demon-
  strates the benefit of terracing in resource conservation.  Average annual
  soluble N  and P  losses were quite low and never exceeded 1% of the annual
  fertilizer application.   These losses were the highest during P3 from the
  contour-farmed watersheds.  Water and sediment weighted nutrient concentrations
 were the highest from the contour-farmed watersheds during P3, when residues
  covered the soil surface.  Leaching of soluble nutrients from the residue
 and the greater selectivity of the  soil erosion process for the finer fractions
 of the soil (i.e.,  clay and organic material)  during snowmelt runoff are
 probably the factors responsible.


 78:058-009
 A WATER QUALITY PLANNING MODEL WITH MULTIPLE TIME,  POLLUTANT,  AND SOURCE
 CAPABILITIES,
 DeLucia,  R.,  McBean,  E.,  and Harrington, J.
 Meta Systems  Inc.,  Cambridge,  Massachusetts.
 Water Resources Research, Vol.  14,  No.  1,  p  9-14, February,  1978.  4 fig,  12 ref.

 Descriptors:   *Water pollution control, *Planning,  *Waste treatment, Constraints,
 Optimization,  Mathematical models,  Systems analysis,  Economies of scale.

 The imposition of recent U.S.  legislative  requirements  (Public Law  (PL)  92-500)
 with the  1977  and 1983-1985 water quality  goals requires that water  quality
 management plans must weigh both degree of treatment and capacity expansion
 questions. A  planning model capable of reflecting  the  implications  of the
 pollutant constraints and the  scale economies of point  source abatement implicit
 in  the legislation  is developed.  The model  captures within a mathematical pro-
 gramming  format  important characteristics  of decisions  associated with the time-
 related water pollution  control goals of PL  92-500.  The  model's  unique features
 are the utilization of a  biomass potential parameter as  a measure of water quality
 and a set  of heuristic procedures involving  linearization of the  waste treat-
 ment capacity-removal curves.  These features allow avoidance of  nonconvexity
 problems associated with  analogous models.   The model also includes  the usual
 BOD, DO, N, and  P water quality measures;  it was applied  in a recent planning
 study for  the Saint John  Basin in Maine.


 78:058-010
 STEADY STATE RIVER QUALITY MODELING  BY SEQUENTIAL EXTENDED KALMAN FILTERS,
 Bowles, D.S., and Grenney, W.J.
 Utah Water  Research Laboratory, Logan.
Water Resources  Research,  Vol. 14,  -No. 1, p 84-96,  February, 1978.  11 fig, 3
 tab, 14 ref, 1 append.

 Descriptors:  *Water quality, *Utah, *Rivers, *Model studies, *Mathematical
models., Pollutants,  Dissolved oxygen, Water pollution, Biochemical oxygen demand.
Algae.
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 Sequential  extended Kalman  filters  (EKF) were applied as a  technique for steady-
 state  river water quality modeling.  The approach was demonstrated by using
 water  quality  data collected over a  36.4-mi  stretch of the  Jordan River, Utah.
 Each EKF was used to represent a river reach in which hydraulic and quality
 characteristics were judged fairly uniform.  Mean and variance boundary condi-
 tions  between  successive filters were adjusted to represent the effects of
 variance estimates of 'the system state (water quality parameters) ana confidence
 intervals on these estimates were provided by combining two independent estimates
 of  the system  state.  The independent estimates were based  on  (1) predictions
 from an "internally meaningful" model of the stream transport processes and bio-
 chemical transformations, and  (2) measurements of the water quality parameters.
 The estimates  were combined by a weighting procedure based  on uncertainties
 associated  with each estimate.  A smoothing  algorithm also  was applied in
 order  that  estimates from passes of  the filter procedure in both the downstream
 and upstream directions could be combined.   In this way, information contained
 in  the measurements was used both upstream and downstream of the location of the
 measurement.   The calibration capability of  the filter procedure was demonstrated
 by  simultaneous estimation  of the state vector and one of the model coefficients.
 This capability also was used to estimate simultaneously the rate of lateral
 loading for one of the water quality parameters.  Simultaneous estimation of
 coefficients of lateral loading was  shown to increase the uncertainty associated
 with filter estimates because of the inclusion of uncertainty associated with
 these  coefficients and lateral loading rates.


 78:05B-011
 EFFECT OF SOIL MIXTURES AND IRRIGATION METHODS ON LEACHING  OF N IN GOLF GREENS,
 Mitchell, W.H., Morehart, A.L., Cotnoir, L.J., Hesseltine,  B.B., and Langton, D.N.,
 III.
 Delaware University, Newark, Department of Plant Science.
 Agronomy Journal, Vol. 70,  No. 1, p  29-35, January-February, 1978.  5 fig, 5 tab,
 15 ref.

 Descriptors:   Leaching, Golf courses, Nitrogen, Nitrates, Mixing, Sprinkler
 irrigation. Subsurface irrigation, Environmental effects, Turf grasses, Inhibitors.

 The influence  of soil mixtures, irrigation systems, and N sources on N leaching
 was studied in experimental, though  functional, golf greens from 1973 to 1976.
 Sprinkler irrigation was compared with subsurface irrigation.  Soil mixtures
 contained from 60 to 80 percent sand and variable amounts of silt loam topsoil,
 calcined clay  and humus.  Nitrogen treatments included activated sewage sludge,
 ureaform, ammonium nitrate, 30% N solution,  anhydrous ammonia and nitrapyrin.
 Nitrogen leached primarily  as NO3-N.  Even though about 75% of the added was
 NH4-N, N solution (30% N)  applied through the subsurface irrigation system
 caused a sharp increase in  N03-N in the drainage water.  Anhydrous ammonia with
 or without  nitrapyrin reduced NO3-N leaching losses for one to two weeks but
 had little  effect on the average N03-N concentration over a forty-seven day
 period.  Subsurface irrigation stimulated turfgrass growth  in bands about 20 cm
 wide located above the irrigation lines.  Appearance of growth bands was
 associated  with low temperatures and increased levels of NO3-N in proximity to
 the irrigation lines.  Banding was most apparent in soil mixtures containing low
 levels of residual soil N and absent when turfgrass was adequately fertilized
 with N.


 78:058-012
 NATURAL VEGETATION AS A SOURCE OF DIFFUSE SALT WITHIN THE COLORADO RIVER BASIN,
 Malekuti, A.,  and Gifford,  G.F.
 Utah State  University, Logan,'Department of  Range Science.
 Water  Resources Bulletin,  Vol. 14, No. 1, p  195-205, February, 1978.  8 fig,
 4 ref.

 Descriptors:   *Salts, *Colorado River Basin, *Ranges, ^Vegetation, Leachate,
 Overland flow,  Gullies, Channels, Dissolved  solids, Subsurface flow.

 Foliage and litter leachate from selected natural vegetation in the Price River
 Basin  (within  the Upper Colorado River Basin) was studied to determine the
 probable impact of plants on the amount of diffuse salt movement from rangeland
watersheds.  Calculations using concentrations of various leachates and


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 characteristics of range sites expected to be high salt producers indicated that
 plants contribute between 0.01 and 0.02% or less of the total annual salt load
 to the Price River.  Therefore, it was concluded that plants are not a significant
 source of diffuse salt within the Colorado River Basin.


 78:058-013
 LINE SOURCE DISPERSION WITH APPLICATION TO MIXING IN RIVER CHANNELS,
 Shen, H.T.
 Clarkson College of Technology, Potsdam,  New York,  Department of Civil and
 Environmental Engineering.
 Water Resources Bulletin, Vol.  14,  No.  1, p 35-45,  February,  1978.   4  fig,  22 ref.

 Descriptors:   *Dispersion,  *Solutes,  *Rivers,  *Model studies,  *Path of pollutants,
 Channel flow,  Lime, Mixing,  Uniform flow,  Hydraulics.

 Two-dimensional solutions for transient dispersion of nonconservative dispersants
 in uniform flow resulting from a transverse line source of variable concentration
 were obtained using multiple integral transformations.   In general, the solutions
 were in integral forms,  which can be  evaluated efficiently using Filon's
 quadratures.   Examples were  presented for  cases of practical  interest.  Applicabi-
 lity of the solution for modeling dispersion in natural river  channel where  the
 distribution  of flows across the channel  is nonuniform was discussed.


 78:058-014
 ASSESSMENT OF METHODS FOR COMPUTING STORM  RUNOFF LOADS,
 Wu,  J.S.,  and Ahlert,  R.C.
 Rutgers University,  Piscataway,  New Jersey,  Department of  Chemical  and  Biochemical
 Engineering.
 Water Resources Bulletin, Vol.  14,  No.  2,  p 429-439,  April, 1978.   1  fig,  1  tab,
 21 ref.

 Descriptors:   *Storm runoff,  *Water pollution  sources,  *Model  studies,  Mathematical
 models,  Evaluation,  Land use, Water quality, Path of pollutants, Runoff, Computer
 models.

 Nonpoint source pollution has been  characterized,  in magnitude and  in concentrations
 of pollutants,  by  intermittent  and  impulse-type  discharges  into  receiving waters,
 causing shockloading problems for the  ecosystems  of  these water bodies.  The
 quality of storm runoff  appears  random  and  complex  in  nature.  There  are not yet
 universally applicable assessment tools for  analysis and evaluation of  the impacts
 and  contributions  of pollutant  loads  to receiving waters.  This paper reviewed
 and  recommended methods  for  predicting  storm runoff loads.  The state-of-the-art
 for  storm  runoff pollution prediction includes:  zero-order, direct,  statistical,
 and  descriptive methods.  For transient water quality analysis of individual
 storm events,  it is  essential to  have an efficient sampling program for data
 collection and  a technically  sounded  method of data analysis.  Intensive sampling
 is considered necessary  to a  detailed time history of runoff flows and  loadings
within  a storm  and for a limited  number of storms.  Homogeneous-land-use and
 statistical-synthetic approaches  are  recommended as accurate and practical
methods  for storm-runoff-load..prediction. These two approaches are event-oriented,
 predicting time-varying  runoff loads  for transient water quality analysis, uti-
 lizing  data collected from intensive  sampling programs.


 78:058-015
MODEL FOR  SHORT-ATTACHED THERMAL  PLUMES IN RIVERS,
Paily, P.P., and Sayre, W.W.
NALCO Environmental Sciences, Northbrook, Illinois.
Journal of  the Hydraulics Division, American Society of Civil Engineers, Vol.
104, No. HY5, Proceedings Paper 13762, p 709-723, May, 1978.  8 fig, 1 tab,
18 ref, 2  append.

Descriptors:  *Thermal pollution, *Rivers, *Powerplants, *Missouri river,  Model
studies, Mathematical models, Turbulence, Heated water, Temperature, Mixing.

Side discharges of power plants thermal effluents into natural rivers  cause the
formation of thermal plumes,  the shape and orientation of which depend upon both


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 the discharge conditions and the ambient flow characteristics.   When the
 turbulence level of the ambient flow is high, rapid vertical mixing is  achieved
 between the effluent discharge and the river flow,  and the thermal  plume becomes
 shore-attached with the maximum temperatures within the plume occurring along
 the near shore.  In order to determine the isotherm patterns within shore-
 attached thermal plumes, a solution of the depth-integrated steady-state
 convection-diffusion equation was obtained.   The solution was cast  in terms  of
 space-cumulative discharge coordinates, thus allowing the inclusion of  the
 effects of cross-channel flow induced by channel curvature in the model.


 78:05B-016
 TWO-DIMENSIONAL PLUME IN UNIFORM GROUNDWATER PLOW,
 Wilson, J.L.,  and Miller,  P.J.
 Massachusetts  Institute of Technology,  Cambridge, Department of  Civil Engineering.
 Journal of the Hydraulics Division,  American Society of Civil Engineers;  Vol.
 104,  No.  HY4,  Proceedings Paper 13665,  p 503-514, April,  1978.   6 fig,  17 ref,
 3  append.

 Descriptors:   *Groundwater,  *Dispersion, *Water  pollution,  *New  York, Model
 studies,  Mathematical models,  Adsorption,  Path of pollutants, Wells,  Groundwater
 movement.

 A  simple  analytical model of a two-dimensional plume of groundwater pollution
 was  developed  and applied to the study  of  hexavalent chromium contamination  of
 Long  Island, New York.   The  model was based  on a depth-averaged  mass  transport
 equation  accounting for convection,  dispersion,  linear equilibrium  adsorption,
 and decay,  and was  applicable  to the study of pollution migration from  point
 sources in shallow groundwater aquifers.   The pollutant concentration description
 was based  on a depth-averaged  mass transport equation accounting for  convection,
 dispersion, linear  equilibrium adsorption, and decay,  and was applicable  to  the
 study of pollution  migration from point sources  in  shallow  groundwater  aquifers.
 The pollutant  concentration  description was  based on an asymptotic  solution  to
 Hantush's  well function for  a  leaky  aquifer  and  was  accurate in  the far field
 downstream of  the source.  The  model results were easily  visualized and evaluated
 when  plotted as contour lines  of equal  concentration using  a simple graphical
 procedure,  making it convenient to examine the development  of the plume over
 time  and  to evaluate the sensitivity of the  plume to parameters.


 78:058-017
 DISPERSIVE SOURCES  IN UNIFORM GROUNDWATER  FLOW,
 Hunt, B.
 Canterbury  University,  Christchurch,  New Zealand, Department of  Civil Engineering.
 Journal of  the Hydraulics  Division,  American Society of Civil Engineers,  Vol.
 104,  No. HY1,  Proceedings  Paper  13467,  p 75-85,  January,  1978.   2 fig,  9  ref, 3
 append.

 Descriptors:   *Dispersion, *Groundwater, *Uniform flow,  *Water pollution  sources,
 Water resources,  Steady  flow, Groundwater  movement,  Model studies,  Mathematical
 mode'ls, Equations.

 Solutions were  given  for  instantaneous,  continuous,  and steady-state sources of
 pollution  in uniform  groundwater  flow.  Then  the  solutions were  used to determine
 how long a  continuous source must  be  in place before  steady-state conditions are
 approached, to  determine  the effect  of  a finite  aquifer depth upon  solutions for
 an infinite aquifer depth, to calculate maximum  concentrations for  instantaneous
 sources, and to determine  the time required  for  solutions for a  po'int source and
 a source of finite size  to approach  each other.


 78:05B-018
 SIMULATION OF NITROGEN MOVEMENT, TRANSFORMATIONS, AND PLANT UPTAKE  IN THE ROOT
 ZONE,
 Davidson, J.M., Rao, P.S.C., and Selim, H.M.
 Florida University, Gainesville, Department of Soil Science.'
 In:  Proceedings of National Conference on Irrigation Return Flow Quality Manage-
ment, Colorado State University, Fort Collins, Colorado, p 9-18,  May 16-18,  1977.
 7 fig,  1 tab,   28 ref.


                                     186

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 Descriptors:   *Simulation  analysis, Model studies, Nitrogen, Soil water, Soil
 water movement,  Irrigation, Nitrification, Denitrification, Mineralization.

 Two simulation models, a detailed research-type and a conceptual management-type,
 for describing the fate of nitrogen in-the plant root zone are discussed.  Pro-
 cesses considered in both models were:  one-dimensional transport of water and
 water-soluble  N-species as a result of irrigation/rainfall events, microbiologi-
 cal N-transformations  and  uptake of water and nitrogen species by a growing crop.
 The research-type model involves a finite-difference approximation  (explicit-
 implicit) of the partial differential equations describing one-dimensional water
 flow and convective-dispersive NH4 and NO3 transport, along with simultaneous
 plant uptake and microbiological N-transformations.  Ion-exchange (adsorption-
 desorption) of NH4 was also considered.  The microbiological transformation
 incorporated into the model describe nitrification, denitrification, minerali-
 zation and immobilization.  All transformation processes were assumed to be
 first-order kinetic processes.  The numerical solution was flexibile in its
 soil surface boundary conditions, as well as initial conditions for soil water
 content and nitrogen concentration distributions in the soil profile.  The
 solution can also be used for nonhomogeneous or multilayered soil systems.   The
 research-type model involves a detailed description of the individual process
 and requires a large number of input parameters, most of which are frequently
 unavailable.   Because of this, a more simple  management-type model was developed.
 Several simplifying assumptions were introduced into the management model.
 This model requires a minimal amount of input data by the user,  and provides
 a gross description of the behavior of various nitrogen species  in the plant
 root zone.


 78:05B-019
 TRANSPORT OF MICROORGANISMS IN SAND COLUMNS,
 Wollum,  A.G.,  II, and Cassel,  O.K.
 North  Carolina State University,  Raleigh,  Department of Soil  Science.
 Soil Science Society of America Journal,  Vol.  42,  No.  1,  p 72-76,  January-February,
 1978.   6  fig,  5 tab,  8 ref.

 Descriptors:   Micoorganisms,  Saturated flow,  Wastes,  Sewage effluents,  Bacteria.

 Transport of  streptomycete conidia  through  saturated columns  of  uniformly packed
 sand was  studied  using miscible displacement  techniques.   Autoclaved sand was
 uniformly packed  to give sand  columns  20.3  and 152 cm high.   Mean  pore  water
 velocities  ranged from 14.4 to  131  cm/hour.   A pulse of sterile water containing
 from 10000  to  1000000  conidia  and tagged with 36C1 was  displaced through each
 column with sterile water.   Column  effluent was  collected'and analyzed  for
 conidia by  serial dilution techniques  utilizing  starch-casein agar.  At the  termi-
 nation of each  run,  the column  was  sampled and analyzed for conidia distribution.


 78:058-020
 A CASE STUDY-NITRATES  IN THE UPPER  SANTA ANA  RIVER BASIN  IN RELATION TO GROUNDWATER
 POLLUTION,
 Ayers, R.S.
 California University,  Davis, Department of Land,  Air and Water Resources.
 Proceedings of  National Conference on Management of Nitrogen  in Irrigated Agricul-
 ture, California  University, Sacramento, California, p 355-367, May 15-18, 1978.
 2 fig, 1  tab, 4 ref.

 Descriptors:  Nitrates, Nitrogen, Water managment  (applied), Fertilization, Waste
 disposal, Pollutant identification.

 In response to  a  request from the Santa Ana Watershed Planning Agency (a regional
 planning  agency)  the Kearney Foundation of Soil Science of the University of
 California conducted an interdisciplinary three-month study of the nitrate prob-
 lem in the Basin.  The study was limited to the upper part of the basin where
 nitrate degradation of waters was more serious.  The study included 1)  a review
 of available data to identify existing areas of high nitrate concentrations in
 underground waters, 2) a review of past land use, water and fertilizer use and
waste disposal practices, and 3) estimates of the impact of irrigation, fertili-
 zation and use of animal wastes on leaching of nitrate from root zones.  Guide-
 lines for the use of water, fertilizers and manures were developed.


                                    187

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 78:05B-021
 ESTIMATING THE INFLUENCE OF SOIL RESIDENCE TIME ON EFFLUENT WATER QUALITY,
 Jury, W.A.
 California University, Riverside, Department of Soil and Environmental Sciences.
 Proceedings of National Conference on Management of Nitrogen in Irrigated Agri-
 culture, California University, Sacramento, California, p 265-290, May 15-18,
 1978.  6 fig, 1 tab, 30 ref, 12 equ.

 Descriptors:  Effluents, Water quality, Travel time, Drainage, Tile drainage,
 Nitrates.

 Models are proposed to calculate the time required for dissolved chemicals to move
 from the soil surface to either underlying groundwater in the case of free drain-
 age or to tile drain outlets in the case of artificial drainage.  The models
 assume that dissolved substances are transported primarily by moving soil solu-
 tion, which displaces soil water initially present in the wetted pore space
 (piston flow approximation).  For free drainage, this results in a single travel
 time equation which is a function of soil water content and drainage volume.  For
 tile drainage, the travel time /depends also on the surface entry point, which is
 illustrated with a graph showing residence time as a function of place or origin.
 This graph may be used for all tile drain systems.  Calculations are presented
 to show the influence of travel time on drainage concentrations, illustrating
 also how tile drain concentrations are a mixture of contributions from different
 parts of the field arriving at different times.  Field studies of salt movement
 are analyzed and compared to the model predictions, with differences explained on
 the basis of soil variability or stagnant water in part of the wetted pore space.


 78:058-022
 "BEST MANAGEMENT PRACTICES" FOR SALINITY CONTROL IN GRAND VALLEY,
Walker, W.R., Skogerboe, G.V., and Evans, R.G.
 Colorado1 State University, Fort Collins, Colorado, Department of Agricultural
 and Chemical Engineering.
 Publication No. EPA-600/2-78-162, July, 1978.  113 p, 21 fig, 11 tab, 46 ref.

 Descriptors:  Irrigation, Fluid infiltration, Salinity, Seepage, Water distribution,
Water loss, Water pollution, Water quality, Sprinkler irrigation.

A nontechnical summary of several research activities in the Grand Valley is given.
Analyses of alternative measures of reducing the salt load originating from the
Valley as a result of irrigation return flows are presented.  These alternatives
 include conveyance channel linings, field relief drainage, on-farm improvements
 (such as irrigation scheduling, head ditch linings, sprinkler and trickle irriga-
 tion) , economic control measures such as taxation and land retirement, modified
 legal constraints, and collection and treatment of return flows, with desalting
 systems.  The best management practices for salinity control in the Grand Valley
 should be primarily the structural rehabilitation and operational modification
of the local irrigation system lying below the turnouts from the major canal
 systems.  Canal linings appear in the optimal strategies at higher levels of
valley-wide salinity control emphasis but only so far as lining the Government
Highline Canal is concerned.  Desalting would become a cost-effective alternative
after major irrigation system improvements are implemented.


 78:058-023
LOSS OF SPRAY AND PELLETED PICLORAM IN SURFACE RUNOFF WATER,
Bovey, R.W., Richardson, C., Burnett, E., Merkle, M.G., and Meyer, .R.E.
Agricultural Research Service, College Station:, Texas.
Journal of Environmental Quality, Vol. 7, No. 2, p 178-180, April-June, 1978.
 3 tab, 9 ref.

Descriptors:  *Texas, "Herbicides,  *Agricultural runoff, *Weed control, *Pesticide
residues, ^Surface runoff, Watersheds (basins), Rainfall, Precipitation (atmo-
 spheric), Rainfall-runoff relationships.

This investigation was. conducted to determine the concentration of picloram,
applied as the pelleted formulation, in surface runoff water that may move from
a treated watershed to untreated areas as a result of natural or simulated rainfall*
Movement of surface and subsurface applied picloram in surface runoff water also



                                      188

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 was investigated.  The potassium salt of pelleted picloram was applied at 2.24
 kg/ha  (acid^equivalent) to a 1.3-ha rangeland watershed supporting stands of
 honey mesquite.  Surface runoff of 1.5 cm from a 2.1 cm rain received two days
 after treatment contained an average of 2.8 ppm picloram.  Picloram content
 declined rapidly and runoff water contained less than 5 ppm picloram by 2.5 mo
 after application.  Loss of the potassium salt of picloram from grassland*
 watersheds in surface runoff water was similar whether the picloram was applied
 as an aqueous spray or as a pellet.  Picloram applied subsurface was lost in
 surface runoff water, but in lower concentrations than when applied to the soil
 surface.


 78:058-024
 ARSENIC CONCENTRATIONS IN SURFACE RUNOFF FROM SMALL WATERSHEDS IN TEXAS,
 Richardson, C.W., Price, J.D., and Burnett, E.
 Agricultural Research Service, Temple, Texas.
 Journal of Environmental Quality, Vol. 7, No.  2, p 189-192,  April-June,  1978.
 1 fig, 5 tab, 10 ref.

 Descriptors:  *Arsenicals (pesticides),  *Cotton, *Texas,  *Desiccants,  Arsenic
 compounds.  Water quality, Pesticides,  Surface  runoff,  Soil contamination.

 This study was conducted to determine  the movement of  arsenic  by surface  runoff
 after application of arsenic acid for  desiccation of cotton.  Arsenic  acid was
 applied at 6.6 kg/ha during the cotton year of a cotton-grain  sorghum-oats
 rotation.   The concentration of arsenic  dissolved in the  runoff water  was  highest
 during the  first runoff event after application and decreased  during subsequent
 events.  Arsenic concentrations in the first runoff after treatment ranged from
 250 to 18  ppb, depending on time and tillage after application.   Tillage  that
 incorporated treated plant material into the soil reduced arsenic concentration
 in runoff water.   After two or three runoff events,  the arsenic concentration
 decreased  to 10 to 20 ppb and remained essentially constant  until the  next appli-
 cation three years later.   The arsenic concentration of the  sediment from  the
 watersheds  averaged 20 ppm and appeared  to be  related more to  the arsenic  con-
 tent of the soil than to the length of time or the tillage between arsenic acid
 application and first runoff.   Assuming  average annual  runoff  and sediment yield,
 the amount  of arsenic that would be transported from a  watershed  by runoff and
 erosion is  about 7% of the:amount applied.   Part of  the arsenic  that moves from
 a  watershed may be arsenic that occurs naturally in  the soil.  Of the  total
 arsenic  moved by a watershed,  38% would  be in  solution  and 62% would be attached
 to the sediment.


 78:05B-025
 DISPOSITION OF 15N-LABELED FERTILIZER  NITRATE  APPLIED DURING CORN CULTURE  IN
 FIELD  LYSIMETERS,
 Chichester,  F.W.,  and Smith, S.J.
 Grassland-Forage  Research  Center,  Temple,  Texas.
 Journal  of  Environmental Quality, Vol. 7,  No.  2,  p 227-233, April-June, 1978.
 3  fig,  5 tab,  21  ref.

 Descriptors:   Nitrates, Fertilizers, Water quality,  Denitrification, Leachate,
 Runoff,  Nitrogen  cycle, Lysimeters, Sweet  corn, Ohio.

 Calcium  nitrate labeled with 5.5%  15N was  applied at 336 kg/ha nitrogen (N) to
 each of  two conventional tillage  and two mulch minimum  tillage field lysimeters
 continuously  cropped  to corn  (Zea mays L.).  Disposition of the labeled N was
 followed for  three  years, particularly relative to its effect on water quality.
An  accounting  of applied 15N for  the study period showed that< 2% moved in runoff,
 approximately  30% was  leached in percolate, 25 to 30% was recovered by the corn
crop, and from 10 to  30% remained in the soil.   On the basis of a balance sheet
constructed from the data, 15N gaseous loss  (presumably mainly by denitrification)
was estimated  to range from 6 to 26% of that applied.  The magnitude of gaseous
 loss of N appeared  to vary as a function of lysimeter management history,  with
the systems under improved soil fertility management exhibiting less gaseous
 loss due to greater immobilization of 15N in the soil organic fraction.
                                      189

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  78:058-026
  PERSISTENCE  OF  TEBUTHIURON  IN SURFACE  RUNOFF WATER,  SOIL, AND VEGETATION IN THE
  TEXAS  BLACKLANDS  PRAIRIE,
  Bovey,  R.W.,  Burnett,  E., Meyer,  R.E. ,  Richardson, ~C.,  and  Loh, A.
  Agricultural Research  Service,  College  Station, Texas.
  Journal of Environmental Quality,  Vol.  7, No.  2, p 233-236, April-June, 1978.
  5  tab,  12 ref.

  Descriptors:  *Herbicides,  *Agricultural chemicals,  Water quality, *Texas, Urea
  pesticides,  *Agricultural runoff,  Leaching, Soil contamination, Water pollution
  sources, Persis tence.

  The  concentration of tebuthiuron  herbicide applied in the spray or pellet form
  was  measured in surface runoff  water from watersheds which  received natural or
  simulated rainfall.  The persistence of tebuthiuron  in  soil and vegetation was
  also investigated.  Pelleted tebuthiuron was applied at 2.24 kg/ha (active
  ingredient)  to  a 1.3-ha rangeland watershed.  A 2.8-cm  rain, two days after
  application,  produced  0.94  cm runoff which contained an average of 2.2 ppm of
  tebuthiuron.  Tebuthiuron concentration decreased rapidly with each subsequent
  runoff  event and after 3 mo was less than 0.05 ppm;  none was detected in runoff
  water  one year  after treatment.   The concentration of tebuthiuron, applied as a
  spray  at 1.12 kg/ha, decreased  to  less  than 0.01 ppm within 4 mo in runoff from a
  small plot which received simulated rainfall.  On 0.6-ha plots, mean tebuthiuron
  (sprays and  granules)  concentration was 0.50 ppm or  less in water when the first
  runoff  event  occurred  2 mo  after  application.  Concentrations of tebuthiuron in
  soil and grass  from pellet  applications were Ibst (less  than 1 ppm) and decreased
  with time.


  78:058-027
  THE  EFFECT OF HIGH  2,4-D  CONCENTRATIONS ON DEGRADATION AND CARBON DIOXIDE
  EVOLUTION IN  SOILS,
  Ou,  L-rT. Rothwell, D.F. , Wheeler,  W.B., and Davidson, J.M.
  Florida University, Gainesville,  Department of Soil  Science and Food Science.
  Journal of Environmental Quality,  Vol. 7, No. 2, p 241-246, April-June, 1978.
  6  fig,  6 tab, 13 ref.

  Descriptors:  Pesticides,  Herbicides, Pesticide residues, Persistence, Microbial
  degradation,  Pesticide toxicity, Carbon dioxide, Waste disposal.

 A  laboratory  experiment was conducted to determine the degradation of high
  concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid) and C02 evolution in
three soils.  Two forms of 2,4-D technical grade and  formulated, were added to each
soil  at  rates of 50, 500, 5,000  and 20,000 micrograms/g of soil (ppm).  Degradation
of  the 2,4-D was measured by 14C02  evolution resulting from the oxidation of uni-
formly ring-labeled carbon.  At  an  application rate of 500 ppm, all three soils
degraded 2,4-D.  At 5,000 and 20,000 ppm, degradation occurred in the Webster
silty clay loam and Terra Ceia organic soil, but not  in the Cecil sandy loam
during 80 days of incubation.  The  degradation rate was generally higher for the
formulated 2,4-D than the technical grade material.   For the higher 2,4-D concen-
trations, 5,000 or 20,000 ppm, when extensive degradation occurred, total C02
evolution was also greatly stimulated, and the pattern of total C02 evolution rate
exhibited a two-peak response.  Carbon dioxide-carbon (C02-C) from the first peak
appeared to be mainly from the formulation materials or from the impurities and
C02-C from the second peak was mainly from 2,4-D-C.


78:058-028
PARAQUAT SORPTION AS A FUNCTION OF PARTICLE SIZE IN NATURAL SEDIMENTS,
Karickhoff,  S.W., and Brown,  D.S.
Environmental Research Laboratory,  Athens,  Georgia  30605.
Journal of Environmental Quality, Vol. 7, No.  2, p 246-252,  April-June, 1978.  1
fig, 6 tab,  13 ref, 9 equ.

Descriptors:   Paraquat,  Sorption, Adsorption,  Particle size,  Pesticides,  Pollutants/
Sediments, Isotherms, Cation exchange, Clay minerals.

The distribution of sorbed  paraquat as a function of particle size (sand through
clay)  was determined on five  natural sediments.   Paraquat concentrations  in



                                      190

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 individual size fractions varied as much as two orders of magnitude within a
 given sedimeht, showing a pronounced preference for the fine silt and clay
 fractions.  Adsorption isotherms were measured for individual size separates
 on one sediment.  Paraquat distributions in the whole sediment agreed well
 with those computed using the isotherm coefficients determined on individual
 size separates.  Paraquat sorbs by ion exchange, and sorption partition co-
 efficients showed a definite correlation with the cation exchange capacity
 (CEC)  of individual size fractions.  However, exchange sites in different
 fractions differed in their effectiveness in sorbing paraquat, with the fine
 silt and clay exchange sites being more effective than those of the larger
 separates.  In pure clay suspensions (hectorite and montmorillonite), sorbed
 paraquat did not distribute uniformly throughout the clay particle size
 range.  It was concluded that for highly sorbed compounds such as paraquat,
 conventional phase separation techniques for measuring sorption may not
 distinguish sorbed vs. "free" compounds.


 78:058-029
 FATE OF  2, 4-D IN A NAFF SILT LOAM SOIL,
 Wilson,  R.G.,  Jr., and Cheng, H.H.
 Nebraska Panhandle Station University,  Scottsbluff.
 Journal  of Environmental Quality,  Vol.  7,  No.  2,  p 281-286,  April-June,  1978.
 3  fig, 4 tab,  16 ref.

 Descriptors:   Adsorption,  Hydrolysis,  Chemical degradation,  Microbial degrada-
 tion,  Weed control,  Pesticides,  Runoff.

 Laboratory studies were conducted  to determine the adsorption,  desorption,
 hydrolysis,  and breakdown  of commercially formulated isooctyl  ester and  di-
 methylamine  salt of (2,4-dichlorophenoxy)  acetic  acid (2,4-D)  in  a Naff  silt
 loam soil.   More 2,4-D was adsorbed to  the surface soil  than to soil  at  lower
 depths,  and  the percentage of 2,4-D adsorbed decreased as  the  total amount  of
 2,4-D  present  increased.   Formulated 2,4-D isooctyl  ester  applied to  moist
 soil underwent hydrolysis  to the anionic form at  a rapid  rate,  with >80% of the
 ester  hydrolyzed in  72 hours.  High amounts  of 2,4-D in  runoff  (sediment and
 water) retarded the  active degradation  of  carboxyl-14C 2,4-D when 2,4-D was
 incubated  in runoff  from a wheat field  treated with  various  formulations and
 rates  of 2,4-D.   The presence of the ester formulation at  the high rate of
 application  increased  the  lag period before  degradation of carboxyl-14C and
 ring-14C 2,4-D occurred in soil.   However, once the  active breakdown  of
 carboxyl-14C and ring-14c  2,4-D was initiated,  little  difference  could be
 detected in the degradation patterns.  At  the  end  of the 10  weeks  of  incubation
 in runoff  or in soil,  only 1%  of the 14C-2,  4-D originally applied  to the soil
 could  be identified as 2,4-D.


 78:058-030
 TRANSFORMATION AND TRANSPORT  PROCESSES IN AQUATIC  SYSTEMS,
 Baughman,  G.L.
 Environmental  Research Laboratory,  United  States Environmental Protection
Agency,  College  Station Road, Athens, Georgia   30601.
 In:  Symposium on  Environmental Transport and Transformation of Pesticides,
 October,  1976,  Tbilis,  USSR.  EPA-600/9-78-003, February,  1978, Athens, Georgia,
p 98-102.  25  ref, 1 equ.

Descriptors:   Pesticide kinetics, Pesticide removal, Pesticides, Aquatic
environment, Chemical  degradation,  Pollutants, Water pollution, Water pollution
control,  Water  quality, Volatility.

Dynamics  of transformation and transport are described in terms of their controlling
environmental  parameters.  Recent advances in our ability to mathematically
describe  the rate  and  extent of microbiological, chemical, and physical processes
are discussed  and data are presented to illustrate interrelationships between
these processes.
                                      191

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78:058-031
ESTIMATION OF ORGANOCHLORINE PESTICIDE LOSS IN SURFACE RUNOFF WATERS,
Bobovnikova, Ts.I., Virchenko, E.P., Morozova, G.K., Sinitsyna, Z.A., and
Cherkhanov, Yu.P.
Institute of Experimental Meteorology, Obninsk, Union of Soviet Socialist
Republics.
In:  Symposium on Environmental Transport and Transformation of Pesticides,
October, 1976, Tbilis, USSR.  EPA-600/9-78-003, February, 1978, Athens, Georgia,
p 103-107.  1 ref, 1 egu.

Descriptors:  Pesticide removal, Pesticides, Pollutants, Runoff, Water quality,
Water pollution sources. Water pollution, Estimating.

Pesticide migration in water is one of the major pathways of their transport in
the environment.  Surface runoff water which occurs at the watershed as the
result of snowmelt or rainfall causes pesticide removal from the watershed area
(agricultural lands and forests) and their entering rivers and basins.  Investi-
gations in Russia showed that surface runoff from the watershed was the major
source of river water pollution with pesticides.  The experimental results
obtained show that the loss coefficients of organochlorine.pesticides—DDT and
gamma-BBC—were low both at the natural watersheds and at the experimental runoff
plots -{tenth and hundredth fractions of percent).  The gamma-BHC loss coefficient
did not exceed 3.7% even when gamma-BHC was applied in the snow cover before the
snowmelt, that is under the best runoff conditions.


78:058-032
HEXACHLOROCYCLOHEXANE,' METAPHOS, AND CHLOROPHOS DECOMPOSITION IN SOIL AND THEIR
MIGRATION WITH THE WATERS OF SURFACE RUNOFF,
Tarasov, M.N., Korotova, L.G., Demchenko, A.S., and Bra2hnikova, L.V.
Hydrochemical Institute, Novocherkassk, Union of Soviet Socialist of Republics.
In:  Symposium on Environmental Transport and Transformation of Pesticides,
October, 1976, Tbilis, USSR.  EPA-600/9-78-003, February, 1978, Athens, Georgia,
p 108-116.  3 fig, 2 tab, 1 equ.

Descriptors:  Pesticides, Pesticide removal, Pesticide kinetics, Runoff, Pollutants,
Pollution abatement, Water quality, Water pollution.

Great quantities of chemicals and among them pesticides> enter the biosphere due
to intensive chemicalization of agriculture. «Upon the influence of different
factors the greater part of pesticides is decomposed in soil forming primary
products and certain preparations are preserved in soil for a long time due to
high persistency.  Systematic usage of persistent pesticides and those with high
cumulative properties at vast watersheds occupied by agricultural lands may result
in pollution of natural waters.  In order to predict pollution of natural bodies
by pesticides, it is necessary to study the rate of their decomposition in
different soils, migration capability as well as to obtain quantitative charac-
teristics of their removal from agricultural lands.  This paper reports the re-
sults obtained from studies of hexachlorocyclohexane (BHC),  metaphors, and
chlorophors decomposition in soil, their migration capability as well as the
possibility of washing out by surface runoff.


78:053-033
CERTAIN LAWS OF ORGANOCHLORINE PESTICIDE REDISTRIBUTION IN THE SOIL-WATER,
SOIL-PLANT SYSTEM,
Zhdamirov, G.G., Popov, E.E., and Lapina, N.F.
Institute of Experimental Meteorology, Obninsk, Union of Soviet Socialist
Republics.
In:  Symposium on Environmental Transport and Transformation of Pesticides,
October, 1976, Tbilis, USSR.  EPA-600/9-78-003, February, 1978, Athens,
Georgia, p 47-60.  4 fig, 3 tab, 9 ref.

Descriptors:  Pesticides, Pesticide residues, Evaporation, Sorption, DDT,
Environmental effects. Estimating, Persistence, Barley, Clovers.

One of the objectives of this research work was to find the simplest method of
estimating organochlorine pesticide evaporation from soils,  water, and surfaces.
The other one was to determine the quantitative characteristics of pesticide
transport into various species of plants and their distribution in aerial and
root parts of plants depending on their content in soil.
                                      192

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 73:05B-034
 GENERAL LAWS OF THE MIGRATION OF PESTICIDE RESIDUES IN THE DELTA LANDSCAPE UNDER
 IRRIGATION,  ,.
 Sokolov, M.S.
 Institute of Agrochemistry and Soil Science,  Puschino, Union of Soviet Socialist
 Republics, Academy of Sciences.
 In:   Symposium on Environmental Transport and Transformation of Pesticides
 October, 1976,  Tbilis,  USSR.   EPA-600/9-78-003,  February,  1978, Athens,  Georgia,
 p 38-46.

 Descriptors:  Pesticide residues,  Pesticides,  Pollutants,  Herbicides,  Surface
 runoff,  Subsurface runoff,  Self-purification,  Migration, Water  pollution,
 Sorption.

 The  process of  migration determines diverse after  effects  caused by biocides  and
 other zenobiotics (landscape-regional,  regional-basin  and  global ones)  in  the
 biosphere.  Migration can be  characterized as  a  complex of processes of  redistri-
 bution of  zenobiotics (and  the products of their transformation)  in space  and in
 time.   In  the process of redistribution a pesticide can be transformed  into
 various products.   The  leftovers of the parent compound together with  the  pro-
 ducts of its transformation are defined as pesticide residues.   Xenobiotics are
 mainly transported in aquatic medium, in atmosphere and through organism migration.
 In the aquatic  medium xenobiotics  are transported  in the form of a  liquid  runoff
 (true solutions of electrolytes, compounds with  neutral molecules,  and colloidal
 solutions),  and in the  form of a .solid  runoff  (suspensions,  sorbed  substances
 with precolloidal particles or organo-mineral  colloids).   The subsurface transport
 of xenobiotics  is carried out principally in the form  of a liquid runoff.   This
 paper reviews and analyzes  investigations conducted on the aspect of migration
 and  transport of pesticide  residues through surface and subsurface  runoff.


 78:058-035
 BROMACIL IN LAKELAND  SOIL GROUNDWATER,
 Hebb,  E.A.,  and Wheeler,  W.B.
 United States Department of Agriculture,  Forest  Service, Southeast  Forest
 Experiment Station, Marianna,  Florida   32446.
 Journal  of Environmental Quality,  Vol.  7,  No.  4, p  598-601,  October-December,
 1978.  1 fig, 1 tab,  21  ref.

 Descriptors:  Pesticides, Herbicides, Leaching,  Groundwater,  Water  pollution,
 Water  table,  Pesticide residues, Persistence.

 The  objective of  this study was  to evaluate the  probable magnitude  of the problem
 of the leaching of pesticides  into groundwater under extreme  conditions:  a
 sandy  soil  low  in organic matter,  a persistent and mobile  herbicide applied at
 a high rate,  plentiful rainfall, and a water table within  6 m.  Bromacil
 (5-bromo-3-sec-butyl-6-methyluracil) was  applied at the rate  of 22  kg/ha to a
 Lakeland sand bearing scrub vegetation of  small oaks and poor grasses.
 Groundwater  (at depths ranging from 4.5  to 6 m) was sampled from bromacil
 residue  at weekly intervals for two years.  Residue was first found in the
 groundwater  3 mo after application  and was highest  (1.25 ppm) one month later.
 Thereafter,  the amount declined to <0.1 ppm in about a year and <0.001 ppm in two
 years.   Peaks in residues generally followed periods of increased rainfall by
 about two weeks.  Residues  (0.24 ppm) were still detected  in the surface soil
 two years after application.


 78:05B-036
CLOSED FORM  SOLUTION FOR PESTICIDE  LOSS IN RUNOFF WATER,
 Steenhuis, T.S., and Walter, M.F.
Cornell  University, Ithaca, New York, Department of Agricultural Engineering.
Paper No. 78-2031, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers,  June 27-30,  1978, Logan, Utah,  27 p.   4 fig, 5 tab,
17 ref,  25 equ, 1 append.

Descriptors:  Pesticide removal, Pesticide residues, Runoff, Erosion, Overland
flow, Adsorption, Pesticides,  Regression analysis.
                                      193

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A closed form solution for pesticide loss in overland flow is presented based on
the principle that in a zone near the soil surface, mixing zone, rain, soil, and
pesticides intermix.  All input variables are easily measurable except the depth
of the mixing zone.  A depth of 0.9 cm for this zone was found by regression
using pesticide runoff data reported in literature.  For verification, pesticide
runoff data from Southern Georgia was used and a reasonable agreement existed
between observed and predicted values.


78:05B-037
NONPOINT SOURCE POLLUTION FROM COASTAL PLAIN SOILS IN DELAWARE,
Ritter, W.F., Eastburn, R.P., and Jones, J.P.
Delaware University, Newark, Department of Agricultural Engineering.
Paper No. 78-2046, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 26 p.  6 fig, 11 tab,
14 ref.

Descriptors:  Nutrient removal, Runoff, Surface runoff, Return flow, Pollutants,
Water pollution, Water quality, Agricultural watersheds, Rainfall, Delaware.

Nitrogen, phosphorus and organic matter were monitored on four agricultural
watersheds in the Delaware Coastal Plain.  Total nitrogen and total phosphorus
loads in runoff and baseflow were less than the nitrogen and phosphorus loads
in rainfall.


78:053-038
SALT PICKUP BY OVERLAND FLOW IN THE PRICE RIVER BASIN, UTAH,
Ponce, S.L., and Hawkins, R.H.
Colorado State University, Fort Collins, Department of Earth Resources.
Water Resources Bulletin, Vol. 14, No. 5, p 1187-1200, October, 1978.  5 fig,
2 tab, 10 ref, 1 equ.

Descriptors:  Salts, Saline soils, Salt balance, Overland flow, Shales,
Salinity, Utah, Water pollution, Water quality, Colorado River Basin.

This study emphasized a field investigation of salt release to overland flow
from Mancos shale lands of the Price River Basin, Utah.  Although a high degree
of natural variation existed in the data, which precluded the separation of
factors affecting diffuse salt loading that occurs during overland flow, a
simplistic nonpoint source loading function developed on empirical concepts was
fit to the data.  This function was then used to calculate the average annual
salt yield to the Price River by overland flow.  It was found that even under
severe conditions, the salt yields from Mancos shale lands due to overland flow
is relatively minor, accounting for less than 1.5% of the average annual salt
mass transported from the basin by the Price River.


78:05B-039
CONTAMINANT TRANSPORT TO DEEP WELLS,
Weston, R.F., Phillips, K.J., and Gelhar, L.W.
Weston Incorporated, Rosyln, New York.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol.
104, No. HY6, Proceedings Paper 13824, p 807-819, June, 1978.  9 fig, 2 tab,
12 ref.

Descriptors:  *Pollutants, *Water wells, *Groundwater, *Water pollution,
*Groundwater movement, *Groundwater quality, Wastes, Wells, Base flow, Model
studies, Soil water movement, Analytical techniques, Mathematical models,
Theoretical analysis, Water quality, Nitrates, Soil contamination, Well
contamination.

Described herein by analytical and numerical techniques was the process of
convective transport of a conservative contaminant to a deep, partially
screened pumping well overlain by a zone of contaminated water.  The three-.
dimensional flow to the well was treated as a point sink in an anisotropic
medium.  The effects of a regional downward flow, a phreatic surface above the
well, and an impervious lower boundary were evaluated.  The theoretical results
were compared with the observed mitrate contamination of wells in Long Island,


                                       194

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 New York.  It was shown that the local convective transport produced due to
 pumping greatly accelerates the process of contamination and decontamination
 of the wells.


 78:05B-040
 QUALITY OF PERCOLATE BELOW THE ROOT ZONE OF SELECTED VEGETABLES GROWN IN
 NORTHERN GUAM,
 Demeterio, J.L.
 Guam University, Agana. Water Resources Research Center.
 Completion Report PB-280 666, April, 1978, 28 p. 14 tab, 15 ref.

 Descriptors:   *Percolating water, *Water pollution, *Clays, *Fertilizers, *Guam,
 Pesticides, Vegetables, Root zone,  Sevin, Diazinon, Malathion,  Dibron,  Farm
 wastes, Ammonium sulfate,  Nitrogen, Phosphorus,  Percolation, Potassium nitrate
 Tomatoes, Cabbage,  Peppers, Eggplant,  Water quality.

 Northern Guam farms were surveyed in 1976 and 1977 for pesticide and fertilizer
 usage.   The major pesticides used in 1976 and 1977 were sevin,  diazinon,  malathion,
 and dibron.  Kethane was widely used in 1976 but not in 1977.   Animal manure,
 15-15-15 and 16-16-16 were the most widely used  fertilizers in  1976 and 1977.
 A notable increase in the  use of ammonium sulfate occurred in 1977.  The  chance
 of groundwater contamination from agricultural chemicals is minimal since a very
 small  percentage of the land area is currently being utilized for full-time
 farming.   Bench scale lysimeter studies were conducted to determine the concen-
 trations of nitrogen and phosphorus in percolate water after passing the  root
 zone of selected fertilized vegetables.  Tomatoes,  Chinese cabbage, head  cabbage,
 eggplant,  and bell  pepper  were grown using ammonium sulfate, chicken manure,
 potassium nitrate,  and 15-15-15 as  fertilizers.   Potassium nitrate is the best
 nitrogen source but is cost prohibitive and 15-15-15 percolates excessive amounts
 of nitrate and ammonia nitrogen.  Actively growing vegetables used the  nitrogen
 in the  ammonium sulfate and chicken manure at comparable rates.


 78:053-041
 ATMOSPHERIC NITROGEN AND PHOSPHORUS LOADING TO HARP LAKE,  ONTARIO,  CANADA,
 Nicholls,  K.H.,  and Cox, C.M.
 Ontario Ministry of  the Environment, Rexdale,  Water Resources Branch.
 Water Resources  Research,  Vol.  14,  No.  4,  p 589-592,  August, 1978.   2 fig,  3 tab,
 13  ref.

 Descriptors:   *Nitrogen, *Phosphorus,  *Lakes,  *Canada,  *Harp Lake,  Nutrients,
 On-site investigations,  On-site data collections, Atmosphere, Water pollution
 sources. Precipitation  (atmospheric),  Rain,  Snow, Trees,  Pollen,  Hydrogen
 ion concentration, Water pollution.

 Nitrogen and  phosphorus  in precipitation and dry  fallout  (aeolian  sources), as
 well as the pH of rainfall, were measured  over Harp  Lake  in Ontario during  1974.
 Weighted mean concentrations of total  N and total P  during the  ice-free period
 of  collection were 1.91 mg N/l  and  0.105 mg P/l.   Winter  concentrations of  total
 N were  similar, but  total  P concentrations were much lower, averaging 0.013 mg/1
 in  fresh snow.  Total atmospheric loading  of P to the lake was  74.4  P/sq m  yr,
 and the total N loading was 1600 mg N/sq m yr.  About 52%, or 39.0 mg P/sq m yr
 of  the  total  P loading  from the atmosphere was total dissolved  P  (0,22-micrometer
 filtrate), and 28%,  or  20.6 mg  P/sq m  yr, of the total P  loading was dissolved
 reactive P  ("orthophosphate" P).  Dissolved inorganic N loading at  1010 mg  N/sq
m yr comprised about 63% of the total N loading from the atmosphere.  Pollen,
 from a variety of trees surrounding the lake, contributed about 20% of the  total
 P input.  The pH of  rainfall samples ranged from 3.2-to 5.1 with a median value
of  3.9  (n = 14).


 78:058-042
EFFECT OF PH  ON THE ADSORPTION OF TRACE RADIOACTIVE CESIUM BY SEDIMENTS,
Elprince, A.M.
King Faisal University, Dammam, Saudi Arabia, Department of Soil and Water.
Water Resources Research, Vol. 14, No.  4, p 696-698, August, 1978.  1 fig, 1 tab,
12 ref.
                                      195

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 Descriptors:   *Hydrogen ion concentration,  *Cesium,  *Adsorption,  *Sediraents,
 Trace elements,  Radioactive wastes,  Radioactivity, Model  studies, Mathematical
 models,  Sampling,  Surveys,  Laboratory  tests. Water pollution,  Streams,  Rivers.

 The  adsorption of  trace radioactive  cesium  by  sediments from the  Savannah River
 Plant area  follows a  theoretically expected linear relationship between In Kd
 and  the  pH  of  the  equilibrium solution, where  Kd  is  the equilibrium distribution
 coefficient:   Cs adsorbed  (meq/g)/Cs(+) in  solution  (meq/ml).  Theoretically,
 the  slope of these plots is proportional  to the fraction  of surface area occupied
 by pH dependent  charges.   Experimentally, the  slope  becomes 0  after removal of
 hydroxy  Al  interlayers  with citrate  pretreatment.  Thus,  hydroxy  Al interlayers
 are  the  main source for the pH dependent  charges  making Cs+ adsorption  pH
 dependent.


 78:058-043
 NITROGEN INPUTS  AND LOSSES  TOBACCO,  BEAN, AND  POTATO FIELDS IN A _SANDY  LOAM
 WATERSHED,
 Cameron, D.R., DeJong,  R.,  and Chang,  C.
 Agriculture Canada, Swift  Current, Saskatchewan.
 Journal  of  Environmental Quality, Vol. 7, No.  4,  p 545-55.0, October-December, 1978.
 4 fig, 1 tab,  20 ref.

 Descriptors:   Nitrogen  removal, Leaching, Nitrates,  Denitrification, Fertilization*
 Tobacco, Beans,  Potatoes.

 Results  from a 2-year study concerned  with  additions and  losses of N from cropped
 fields in an intensively farmed sandy  loam  watershed in southern  Ontario indicated
 that heavily fertilized burley tobacco (220 kg N/ha  per year)  and potato (165 kg
 N/ha per year) fields can potentially  lose  up  to  52  and 92 kg  N/ha per  year,
 respectively,  from the  75-cm profile by leaching  and denitrification.   Mineral N
 production  rates calculated from results  obtained in the  field over the growing
 season varied  from 0.0  to  0.73 kg N/ha per  year.  The lower rate  resulted from
 leaching losses.   The monitored N03-N  profile  distributions under fertilized bur-
 ley  tobacco and  potato  crops showed  definite leaching patterns.   Soil water samples
 taken periodically from the potato field  at 90 and 150 cm showed NO3-N  moving
 through  the lower  profile in response  to  rainfall 'events.  A plot treated with
 Cl showed no significant Cl leaching losses until early fall when rains moved
 about 45% of the added  Cl below 75 cm.


 78:058-044
 NUTRIENT RUNOFF  FROM FERTILIZED AND  UNFERTILIZED FIELDS IN WESTERN CANADA,
 Nicholaichuk, W.,  and Read,  D.W.L.
 Research Station,  Research  Branch, Agricultural Canada, Swift  Canada, Saskatchewan
 S9H  3X2.
 Journal  of  Environmental Quality, Vol. 7, No.  4, p 542-544, October-December, 1978.
 2 tab, 13 ref.

 Descriptors:  Water quality,  Nitrogen, Phosphorus, Sediments,  Surface runoff,
 Fertilization, Wheat, Snowmelt, Fallowing,  Canada.

 Nutrient transport in surface runoff from snow was measured from -fertilized and
 unfertilized cropped and summer fallowed Wood  Mountain loam fields in semiarid
 southwest Saskatchewan.  The  amount  of nitrogen lost from unfertilized  fields
 during spring runoff exceeded the limits purported to result in algal growth;
 however, the loss was agronomically  insignificant.   It was concluded that since
 the N and P concentrations  in runoff from unfertilized fertile agricultural soils
 exceed Saskatchewan Water Quality criteria, these guidelines may be regarded as
 unattainable under the  present system of cereal cropping  in western Canada.


 78:058-045
TEMPERATURE AND pH AS LIMITING FACTORS IN LOSS OF NITRATE FROM SATURATED ATLANTIC
COASTAL PLAIN SOILS,
Gilliam, J.W., and Gambrell,  R.p.
North Carolina State University,  Raleigh,  Department of Soil Science.
Journal of Environmental Quality, Vol. 7,  No.  4, p 526-532, October-December,
1978.  5 fig,  2 tab, 35 ref.
 (See 78:02K-048)


                                     196

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 7S-.05B-046
 NITROGEN AND PHOSPHORUS LOSSES FROM ORGANIC SOILS,
 Duxbury, J.M., and Peverly, J.H.
 Cornell University, Ithaca, New York, Department of Soil Organic Chemistry.
 Journal of Environmental Quality, Vol. 7, No. 4, p 566-570, October-December,
 1978.  3 fig, 2 tab, 15 ref.

 Descriptors:  Nutrient removal, Organic soils, Leaching, Nitrogen, Phosphorus,
 Runoff, Drainage water, Water quality. Fertilization, Water pollution.

 The nutrient content of drainage water from Histosols located in New York was
 monitored from June 1975 through July 1977.  Continuous flow records and
 nutrient concentration data obtained from daily composite samples were used
 to calculate annual nutrient outputs which ranged from 0.6 to 30.7 kg/ha for
 P04(3-)-P, 39.2 to 87.5 kg/ha for NO3(-)-N, and <1.0 to 1.9 kg/ha for NH4(+)
 -N.  Nutrient concentrations in the drainage water increased with increasing
 flow, so that the greatest output of nutrients was during late winter and
 spring high-flow events.  Maximum observed concentrations were 35 mg/liter
 for NO3(-) and 10 mg/liter for PO4{3-)-P.  The amount of N lost in drainage
 water was similar at all sites and was about 10% of that mineralized; the
 remainder was presumed to be denitrified.  The fiftyfold variability in
 phosphorus output appeared to be related to interactions within the soil pro-
 file rather than fertilizer practices, although these probably contributed to
 the generally high levels found.  It was concluded that fertilizer nitrogen
 additions were unlikely to affect the quantity of N03(-> leached.  The study
 showed that organic soils can contribute to N and P in land runoff in much
 greater proportions than indicated by their area.


 78:05B-047
 REDOX POTENTIALS IN A CROPPED POTATO PROCESSING WASTE WATER DISPOSAL FIELD
 WITH A DEEP WATER TABLE,
 Smith, J.H., Gilbert, R.G., and Miller, J.B.
 Snake River Conservation Research Center, Kimberly, Idaho  83341.
 Journal of Environmental Quality, Vol. "7, No. 4, p 571-574, October-December,
 1978.  2 fig, 2 tab, 9 ref.

 Descriptors:  Oxidation-reduction potential, Waste water (pollution), Waste
 water disposal, Denitrification, Nitrification, Nitrogen, Nitrates, Flood
 irrigation, Water pollution, Groundwater.

 Kedox potential measurements were made in a field irrigated with potato processing
waste water at seven depths of 5 to 150 cm for 14 months.  Irrigation with canal
water mixed with waste water in the summer, and with waste water in the winter,
 decreased redox potentials in the field at some depths for a short time but not
 enough to cause denitrification.  However, as the soil temperature increased in
 the spring, and decomposition of the accumulated waste organic matter accelerated,
 redox potentials decreased after each irrigation at all observed depths.   During
April, redox potentials low enough to promote denitrification (below +225 mV)  at
 90-, 120-, and 150-cm depths in the soil persisted for 2 weeks.  Irrigation with
nondiluted waste water in June and July decreased .redox potentials and denitrifi-
 cation occurred for up to 3 days after irrigations.  As the soil temperature in-
creased in the spring,  nitrification of accumulated organic matter increased soil
nitrates.  Waste watlr irrigations from April to July promoted denitrification,
 removing most of the nitrate from the soil, and thereby decreasing the potential
 for groundwater pollution.



 SIMAZINE4RESIDUE LEVELS IN IRRIGATION WATER AFTER DITCHBANK APPLICATION FOR WEED
CONTROL,

^teeeY^r^e6^^

JSSS 5-S&S2
 1978.  8 fig, 2 tab, 20 ref.
                                      197

-------
Descriptors:  Aquatic weed control, Aquatic weeds, Herbicides, Irrigation water,
Water quality, Gas chromatography.

A field study was conducted to determine the amount of simazine <2-chloro-4,6-
bis  (ethylamino)-s-triazine) likely to be found in irrigation water after ditch-
bank treatment for weed control.  Resulting data are useful in evaluating the
potential impact of simazine on crops irrigated from sprayed canals.  Canals -
were selected in California, Colorado, and Washington for the application of
simazine to both watered and dewatered sites at rates of 2.25 to 7.43 kg/ha.
Simazine levels in flowing canal water immediately after herbicide application
did not exceed 60 raicrograms/liter.  In first-flow samples collected in the
spring from the sites that were dewatered at application, simazine levels peaked
at about 250 micrograms/liter within the treated section but decreased rapidly
to <5 micrograms/liter.


78-.05B-049
STREAM CHEMISTRY AND WATERSHED NUTRIENT ECONOMY FOLLOWING WILDFIRE AND
FERTILIZATION IN EASTERN WASHINGTON,
Tiedemann, A.R., Helvey, J.D., and Anderson, T.D.
United States Department of Agriculture Forest Service, Pacific Northwest
Forest and Range Experiment Station, Forest Hydrology Laboratory, Wenatchee,
Washington  98801.

Descriptors:  Streams, Forest fires, Fertilization, Ureas, Ammonium compounds,
Nutrients, Water quality, Nutrient removal, Washington.

During the first three years after a severe wildfire in 1970, maximum
concentrations of nitrate-N  (NO3-N) in stream water increased from prefire
levels of <0.016 to 0.56 mg/liter on a burned, unfertilized watershed and to
0.54 and 1,47 mg/liter on two watersheds that were burned and fertilized.
Maximum N03-N concentration in stream from an unburned watershed was 0.066 mg/
liter.  Organic N concentrations in streamflow were nearly doubled during the
second year after fire compared to prefire levels.  Concentrations of total
phosphorus in streams from one burned and two burned-fertilized watersheds were
1.5 to 3 times greater than from an unburned watershed.  Combined concentrations
of Ca, Mg, K, and Na in streams prior to fire ranged from 12.0 to 14.9 mg/liter.
Concentrations declined to 7.4-10.5 mg/liter in streams from burned and burned-
fertilized watersheds during the second year after fire  (1972) because of
dilution resulting from increased discharge and were still less in 1975 than pre-
fire levels.  Average inputs of N, P, and the four cations during the five
years of study were 1.23, 0, and 3.56 kg/ha per year.  Yearly N input from pre-
cipitation was sufficient to balance solution losses in three of the five post-
fire years.  Cation losses in solution greatly exceeded precipitation inputs in
all years.  Results indicate that fire and fertilization exerted negligible effects
on chemical water quality for municipal use.


78:058-050
EFFECT OF ENVIRONMENTAL FACTORS ON SURVIVAL OF SALMONELLA TYPHIMURIUM IN SOIL,
Zibilske, L.M., and Weaver, R.W.
Missouri University, Columbia, Department of Agronomy.
Journal of Environmental Quality, Vol. 7, No. 4, p 593-597, October-December, 1978.
6 tab, 18 ref.

Descriptors:  Waste disposal, Pathogenic bacteria, Microorganism, Environment,
Laboratory tests, Persistence.

This investigation was undertaken in the laboratory to determine how accurately
salmonella survival can be predicted when environmental conditions are known.
Salmonella typhimurium was  inoculated into two Texas soils, a clay^and a fine
sandy loam, using cattle manure slurry and saline as inoculum carriers.  Soil
samples were  incubated in the laboratory at three temperatures and moistures:
5, 22, and 39 C; and  0, 0.5, and  >22 atm tension, respectively.  Survival was
monitored  for 12 weeks by direct  spread plating of soil dilutions onto dulcitol-
iron thiosulfate  (DIT) medium developed for this experiment;  The DIT medium
restricted growth of  normal  soil microflora but allowed growth and differentiation
of S. typhimurium.  Statistical evaluation of treatment effects was complex be-
cause of  three  factor  interactions.  Soil moisture and temperature.interacted as


                                      198

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 did soil moisture and inoculation method.  Time as a factor strongly interacted
 with moisture, soil, and temperature.  S. typhimurium died within 1 week in dry
 soil incubated at 39 C, interactions occurred that resulted in survival to 42
 days.  Survival at 5 and 22 C was comparable and-usually longer than at 39 C.
 Salmonella populations increased in some samples at 3 days but declined
 afterward.


 78:053-052
 TRANSPORT OP ANTIBIOTIC-RESISTANT ESCHERICHIA COLI THROUGH WESTERN OREGON
 HILLSLOPE SOILS UNDER CONDITIONS OF SATURATED FLOW,
 Rahe, T.M., Hagedorn, C.,  McCoy, E.L.,  and Kling, G.F.
 Oregon State University, Corvallis, Department of Soil  Science and Microbiology.
 Journal of Environmental Quality, Vol.  7, No. 4, p 487-494,  October-December
 1978.  3 fig, 3 tab, 16 ref.

 Descriptors:   Sewage effluents,  Coliforms,  Groundwater,  Water pollution,  Tracers,
 Waste disposal, Septic tanks, Sewage disposal, Perched  water,  Subsurface  flow.

 Field experiments using strains  of antibiotic resistant Escherichia coli  were
 conducted to evaluate the  events which  would occur when a  septic-tank drainfield
 became submerged in a perched water table and fecal bacteria were  subsequently
 released into the groundwater.   Three separately distinguishable bacterial  strains
 were inoculated into three horizontal lines installed in the A, B,  and C  horizons
 of two western Oregon hillslope  soils.   Movement was evaluated by  collecting
 groundwater samples from rows of modified piezometers (six piezometers/row)
 placed at various depths and  distances  downslope from the  injection lines.   Trans-
 port of E.  coli differed at both sites  with respect to movement rates,  zones in
 the soil profiles through  which  major translocation occurred,  and  the relative
 numbers of cells transported  over time.   Movement rates  of at  least 1,500 cm/hour
 were observed in the B horizon at dhe site.   The strains of  E. coli survived in
 large numbers in the soils examined for at  least 96 hours  and  appeared to be
 satisfactory  as tracers of subsurface water flow.   The  concept of  partial dis-
 placement (or turbulent flow  through macropores)  was discussed as  an explanation
 of the rapid  movement of substantial numbers of microbial  cells through saturated
 profiles.


 78:05B-053
 LEACHING OF CATIONS  AND CHLORIDE FROM MANURE APPLIED TO  AN IRRIGATED SOIL,
 Pratt,  P.F.
 California  University,  Riverside,  Department of Soil Science.
 Journal of  Environmental Quality,  Vol.  7, No.  4,  p  513-516,  October-December,
 1978.   3  fig,  15  ref,  8  equ.
 (See  78:05G-042)


 78:058-054
 EFFECTS OF  SO2  AND NO2 ON  NITRIFICATION  IN  SOIL,
 Labeda,  D.P.,  and Alexander,  M.
 Abbott  Laboratories,  North Chicago,  Illinois   60064.
 Journal of  Environmental Quality, Vol. 7, No.  4, p  523-526, October-December, 1978.
 4  fig,  1  tab,  24 ref.

 Descriptors:  Air pollution,  Nitrification, Nitrates, Fumigants, Nitrites, Ecology.

 Nitrification  in Lima loam, pH 7.2, was not affected by continuous exposure of the
 soil to 0.5 ppm of S02 or to  brief exposures  to higher S02 levels.    Such treat-
 ment did not  increase the levels of  soluble K, Mg, Ca, Mn, Fe, and Al.  Intermit-
 tent exposure of Hudson silty clay loam, pH  5.0, to  S02 reduced the  rate of
 nitrate  formation.  Continuous fumigation of Lima loam with 5 ppm NO2 inhibited
 the rate of ammonium disappearance,  led to greater rates of nitrate  formation,
 and resulted  in nitrite accumulation'.  Nitrite at a  level of 30 micrograms N/g
 of soil also  reduced the rate of ammonium disappearance.  The results demonstrated
 that nitrification in certain soil could be inhibited in areas acutely polluted
with S02 and NO2.
                                      199

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 78:05B-055
 ZINC AND CADMIUM CONTENTS OF AGRICULTURAL SOILS AND CORN  IN NORTHWESTERN
 INDIANA,
 Pietz, R.I., Vetter, R.J., Masarik, D., and McFee, W.W.
 The Metropolitan Sanitary District of Greater Chicago, Canton,  Illinois,
 Research and Development Laboratory.
 Journal of Environmental Quality, Vol. 7, No. 3, p 381-385, July-September,
 1978.  1 fig, 3 tab, 26 ref.

 Descriptors:  Heavy metals, Soil contamination, Environmental effects, Crop
 response, Pollutants, Zinc, Cadmium, Industrial plants, Urbanization, Corn
 (field).

 Soil and corn (Zea mays L.) leaf and grain samplings were conducted in
 northwestern Indiana to determine if airborne heavy metal particulates con-
 taining Cd and Zn from the northwestern Indiana industrial-urban complex,
 situated on the south side of Lake Michigan, were contaminating soils and crops.
 Sampling in the region revealed no widespread metal contamination.  Some metal
 enrichment had occurred on agricultural soils in Gary and East Gary, Indiana.
 Corn leaf concentrations of Cd, Pb, and Zn fluctuated with sampling location,
 but grain Cd and Pb levels remained essentially constant at <0.05 and <0.4
 microgram/gram, respectively.  A comparison of Zn/Cd ratios in soils, and in
 corn leaves and grain, suggested that Cd was more actively accumulated in the
 corn plant but not the grain.  Because of the limited acreage affected and the
 relatively low metal levels observed, no human or animal health problems are
 expected from harvested crops or silage.  The use of log distance vs. log metal
 concentration in regression analysis showed that the limited metal contamination
 of agricultural soils was mainly in a southeasterly direction from the industrial-
 urban area.


 78:05B-056
 PERSISTENCE AND FACTORS AFFECTING DISSIPATION OF MOLINATE UNDER FLOODED RICE
 CULTURE,
 Deuel, L.E., Turner, F.T., Brown, K.W., and Price, J.D.
 Texas A & M University, College Station, Department of Soil and Crop Science.
 Journal of Environmental Quality, Vol. 7, No. 3, p 373-377, July-September,
 1978.  2 fig, 5 tab, 7 ref.

 Descriptors:  Pesticides, Persistence, Return flow, Degradation (decomposition),
 Microbial degradation, Pesticide residues, Submergence, Rice, Oxidation-reduction
 potential, Water pollution.

 Pesticides, essential for the economical production of rice (Oryza sativa L.),
 could pose a serious problem if transported to surface impoundments and estuaries
 along the Gulf Coast via the return flow associated with flooded rice culture.
 Field experiments were conducted under flooded rice cultivation to determine per-
 sistence and half-life of molinate (S-ethyl-hexahydro-1-H-azepine 1-lcarbothioate).
 Persistence and half-life were evaluated with respect to intermittent and con-
 tinuous flow irrigation schemes at normal and excessive application rates of 3.4
 and 11.2 kg/ha molinate, respectively.  Persistence at statistically significant
 levels ranged from 96 to 384 hours following the application, and generally was
more a function of the application rate than irrigation scheme.  Half-life values
 averaged 96 ± 22 hours in intermittent flow plots, and 54 ± 17 hours in continuous
 flow plots over the 3-year experiment.  Application rate had little effect on half-
 life.  Best fit analysis of field data to the first order biological decay equation
 and laboratory studies under flooded soil conditions suggested that biological
 degradation was the principle mode by which molinate was dissipated in the field
 experiment.


 78:058-057
EVALUATING THE ENVIRONMENTAL CONSEQUENCES OF GROUNDWATER CONTAMINATION 1. AN OVER-
VIEW OF CONTAMINANT ARRIVAL DISTRIBUTIONS AS GENERAL EVALUATION REQUIREMENTS,
Nelson, R.W.
BCS Richland, incorporated, Washington, Department of Scientific Systems.
Water Resources Research, Vol. 14, No. 3, p 409-415, June, 1978.  8 fig, 1 tab,
 9 ref.
                                       200

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 Descriptors:   *Groundwater,  *Water pollution,  *Path of pollutants,  *Environmental
 effects,  Model studies, Mathematical models,  Equations,  Pollutants,  Soil contami-
 nation,  Groundwater movement,  Water pollution sources.
            \
 The environmental consequences of subsurface  contamination problems  can be
 evaluated completely and effectively by fulfilling  the following five requirements:
 (1)   determining each present  or future outflow boundary of contaminated ground-
 water,  (2)  providing the location/arrival  time distributions,  (3) providing the
 location/outflow quantity distributions,  (4)  providing these distributions for  each
 individual chemical or biological constituent of environmental  importance, and
 (5)  using the arrival distribution to determine the quantity and concentration
 of each  contaminant that will  interface with  the environment as time passes.  The
 arrival  distributions on which these requirements are  based provide  a reference
 point for communication among  scientists and  public decision makers  by enabling
 complicated scientific analyses to be presented as  simple summary relationships.


 78:05B-058
 EVALUATING THE ENVIRONMENTAL CONSEQUENCES  OF  GROUNDWATER CONTAMINATION 2.  OBTAIN-
 ING LOCATION/ARRIVAL TIME AND  LOCATION/OUTFLOW QUANTITY  DISTRIBUTIONS  FOR STEADY
 FLOW SYSTEMS,
 Nelson,  R.W.
 BCS  Richland,  Incorporated,  Washington,  Department  of  Scientific Systems.
 Water Resources Research,  Vol.  14,  No.  3,  p 416-428, June,  1978.  11  fig,  3 tab,
 20 ref.

 Descriptors:   *Groundwater,  *Water pollution,  *Path of pollutants, *Model  studies.
 Mathematical  models.  Environmental effects, Equations, Pollutants, Soil  contamina-
 tion, Groundwater movement,  Water pollution sources.

 A  steady,  two-dimensional  flow system was  used to demonstrate the application of
 location/arrival time and  location/outflow quantity curves  in determining  the
 environmental  consequences of  groundwater  contamination.  The subsurface geologic
 and  hydrologic evaluations needed to obtain the  arrival  results  involve  a  sequence
 of four phases:   system identification,  new potential determination,  flow  system
 kinematics, and contaminant  transport analysis.   Once  these phases are completed,
 they are  summarized effectively and easily used  to  evaluate environmental  conse-
 quences through the arrival  distributions.


 78:058-059
 EVALUATING  THE ENVIRONMENTAL CONSEQUENCES OF GROUNDWATER CONTAMINATION 3. OBTAIN-
 ING  CONTAMINANT  ARRIVAL DISTRIBUTIONS FOR STEADY  FLOW IN  HETEROGENEOUS SYSTEMS,
 Nelson, R.W.
 BCS  Richland,  Incorporated,  Washington, Department  of Scientific Systems.
 Water Resources  Research,  Vol.  14,  No.  3, p 429-440, June, 1978.  9 fig, 1 tab,
 8  ref.

 Descriptors:   *Water  pollution,  *Groundwater resources,  *Contaminant arrival
 distributions, Groundwater movement, Hydrology, Environmental effects, Grpundwater
 recharge, Mathematical  models,  Steady flow.

 The  versatility  of  the  new contaminant arrival distributions for determining
 environmental  consequences of  subsurface pollution problems is demonstrated through
 application.to a field  example  involving land drainage in heterogeneous porous
materials.  Though  the  four  phases of the hydrologic evaluations are complicated
because of  the material heterogeneity encountered in the  field problem, the
 arrival distributions still  effectively summarize the minimal amount of data re-
quired to determine the environmental implications.  'These arrival distributions
yield a single graph  or tabular set of data giving the consequences of the subsur-
 face pollution problems.  Accordingly, public control authorities would be well
advised to request  that the  results of subsurface pollution investigations be
provided in the  form  of arrival distributions and the resulting simpler summary
curve or tabulation.  Such an objective is most easily accomplished through com-
pliance with the requirements presented by Nelson for assuring a complete sub-
surface evaluation.
                                     201

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 78:05B-060
 EVALUATING  THE  ENVIRONMENTAL CONSEQUENCES  OP  GROUNDWATER CONTAMINATION  4. OB-
 TAINING  AND UTILIZING CONTAMINANT  ARRIVAL  DISTRIBUTIONS  IN  TRANSIENT  FLOW SYSTEMS,
 Nelson,  R.W.
 BCS  Richland, Incorporated,  Washington,  Department  of  Scientific  Systems.
 Water  Resources Research, Vol.  14,  No.  3,  p 441-450, June,  1978.   10  fig, 4  tab,
 4  ref.

 Descriptors:  *Water  pollution,  *Groundwater  contamination, Groundwater resources,
 Groundwater movement,  Hydrology, Environmental effects,  Groundwater recharge,
 Mathematical models,  Transient  flow system.

 The  versatility of  the new contaminant  arrival distributions for  determining
 environmental consequences of subsurface pollution  problems is demonstrated
 through  application to a transient  flow system.   Though  some of the four phases
 of the hydrologic evaluations are more  complicated  because of the time dependence
 of the flow and input contaminant  concentrations, the  arrival distributions  still
 effectively summarize the data required to determine the environmental implica-
 tions.   These arrival distributions  yield  two graphs or  tabular sets  of data giving
 the  consequences of the subsurface  pollution problems  in a simple and direct form.
 Accordingly, the public control  authorities would be able to use  these results
 to choose alternatives or to initiate corrective  actions, depending on the indi-
 cated environmental consequences.


 78:05B-061
 PREDICTIONS OF  HEAT AND MASS  TRANSFER IN OPEN CHANNELS,
 Rastogi, A.K.,  and  Rodi, W.
 Karlsruhe University,  West Germany.
 Journal  of  the  Hydraulics Division,  American Society of  Civil Engineers, Vol. 104,
 No.  HY3, Proceedings  Paper 13639, p  397-420, March, 1978.  6 fig,  24  ref, 2  append.

 Descriptors:  *Mass transfer, *Heat  transfer, *0pen channels, *Model  studies,
 Effluents,  Turbulence,  Dispersion,  Cooling water, Buoyancy, Fluid flow, Froude
 number.

 The  paper described a  three-dimensional  model for calculating the distribution of
 velocity, temperature,  and pollutant concentration  in  open channel flows, and a
 depth-averaged  two-dimensional version  for situations with insignificant stratifi-
 cation and  secondary  currents.  Both models .were  restricted to parabolic flows,
where influences cannot be transmitted upstream.  The  turbulent stresses and heat
 concentration fluxes  appearing in these  equations were determined from the so-
 called k-epsilon turbulence model that solves differential transport  equations
 for  the  turbulence  kinetic energy k and  the rate of its  dissipation epsilon.  In
 the  depth-averaged  model, the bottom shear stress surface heat flux and turbulence
production  due  to bottom shear stress are  accounted for  by source/sink terms in
 the  relevant equations.  The  3D calculations compared  favorably with  available
measurements.   The  2D  and 3D predictions agreed well for high Froude  numbers; for
 a Froude number of  5  they agreed only for  the rough bed, while for the smooth bed
 they start  to deviate  significantly at a Froude number of 10.


 78:058-062
 CASING DEPTHS AND SOLUTE TRAVEL TIMES TO WELLS,
Kirkham, D., and Sotres, M.O.
 Iowa State  University, Ames, Department of Agronomy.
Water Resources Research, Vol. 14, No. 2, p 237-243, April, 1978.   7  fig, 9 ref.

Descriptors:  *Travel  time, *Solutes, *Well casings, Flow nets, Flow  rates, Water
pollution sources,  Water wells,  Aquifers, Path of pollutants.

Partially-penetrating well casing may offer some protection against chemical solutes
such as nitrates and acids from agriculture industry, strip mines, sanitary land-
fills or other pollution sources near wells.  Travel times for solutes depend on
the well and aquifer geometric factors such as well and aquifer geometric factors
 such as well radius, screened length of the well, and thickness of the aquifer.
The  longest and shortest travel times and flow nets were computed for 18 well-
aquifer geometries   assuming piston flow in a steady state along streamlines in a
phreatic (water-table) aquifer and a fixed radius of influence.    Dimensionless


                                      202

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  travel time t1,  increases as the impervious  well  casing  length increases.   Multi-
  plication of t'  by a factor (p/KH)  times  b squared gives the real travel'time,
  where f is aquifer porosity, K is conductivity, H is  the difference in head
  between the water table level and the level  in  the pumped-down well,  and b  is  the
  radius of influence.   These travel  times  should be useful in well design and pro-
  tection from solutes.   Curves of t1  versus 4/b, where r  is  horizontal distance
  from the well center to a point on  top of the aquifer were  given  for  a number of
  geometries.


  78:05B-063
  PHOSPHORUS—A POTENTIAL NONPOINT SOURCE POLLUTION  PROBLEM IN THE  LAND AREAS
  RECEIVING LONG-TERM APPLICATION OF WASTES,
  Reddy,  K.R,,  Khaleel,  R.,  Overcash,  M.R.,  and Westerman,  P.W.
  North  Carolina State University,  Raleigh,  Department of Biological and Agricultural
  Engineering.
  Proceedings of the  1978  Cornell  Agricultural Waste Management Conference  p  193-
  211.   7  fig,  7 tab,  29  ref,  3  equ.
  (See 78:05A-017)


  78:05B-064
  THE PATE OF NITRATE IN SMALL STREAMS AND ITS MANAGEMENT IMPLICATIONS,
  Robinson, J.B., Whiteley, H.R., Stammers,  W., Kaushik, N.K., and Sain, P.
 Guelph University, Guelph, Ontario, Canada, Department of Environmental Biology.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 247-
  259.  6 fig, 2 tab, 20 ref.

 Descriptors:  Nitrates, Nitrogen, Water pollution, Water  quality,  Nitrogen  cycle,
 Streams, Laboratory tests, Management, Denitrification, Nutrient removal.

 The present paper is a continuation of earlier investigations conducted by  the
 authors on nitrogen transformations in'stream-sediment-water systems.   This  paper
 provides further evidence for significant  amounts  of nitrogen loss during transport
 in streams and indicates the stream management options which should enhance  the
 process.


 78:05B-065
 AN APPROACH TO WATER RESOURCES EVALUATION  OF  NONPOINT SOURCES FROM SILVICULTURAL
 ACTIVITIES—A PROCEDURAL HANDBOOK,
 Currier,  J.B., Siverts,  L.E., and Maloney,  R.C.
 Watershed Systems Development Group,  United States  Department of Agriculture—
 Forest Service, Fort Collins, Colorado.
 Proceedings of the 1978 Cornell Agricultural Waste  Management Conference, p  271-
 280.   1 fig,  1 ref.

 Descriptors:   Water pollution control, Water pollution sources,  Forest watersheds,
 Forest  management,  Soil  erosion,  Streamflow, Sediment discharge, Dissolved oxygen,
 Methodology.

 This handbook  provided  an analysis methodology that can be used  to describe and
 evaluate  the changes  to  the water resource  due to nonpoint sources from silvi-
 cultural  activities.  It covered  only  the pollutant generation and transport
 processes  and  did not consider  the economic, social and political aspects of
 pollution  control.   It provided quantitative techniques for estimating potential
 changes in  streamflow, surface  erosion, mass wasting, -total potential  sediment
 discharge,  and temperature.   Qualitative discussions of the impacts of silvicultural
 activities  on dissolved  oxygen, organic matter, nutrients, and introduced chemicals
were also included.  A control section provided a list of demonstrated effective
 control practices and a methodology to be used to select mixtures of these con-
 trols for the prevention and mitigation of water resource  impacts.   Such mixtures
are the technical basis for formulating "Best Management Practices" (BMP's).
Because economic, social, and political analyses were not  discussed in this  chap-
ter, the resulting mixtures of controls are not BMP's.
                                     203

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78:056-067
NONPOINT SOURCES:  STATE-OF-THE-ART OVERVIEW,
Sweeten, J.M., and Reddell, D.L.
Texas A and M University, College Station.
Transactions  of the American Society of Agricultural Engineers, Vol. 21, No. 3,
p 474-483, May-June, 1978.  3 fig, 2 tab, 62 ref.

Descriptors:  *Water pollution sources, *Pollutants, *Nonpoint pollution sources,
Agriculture,  Nutrients, Nitrogen, Biochemical oxygen demand, Chemical oxygen
demand, Farm  wastes, Water pollution.

During the past few years, the term nonpoint pollution source has become ex-
ceedingly important to agriculture.  In 1972, Federal legislation (Public
Law 92-500) was passed bringing many forms of agriculturally related nonpoint
pollution under regulatory authority.  Section 208 of Public Law 92-500 created
a cooperative local/state/Federal system for areawide water quality planning.
Nonpoint pollution sources are a major concern to these Section 208 planners.
During the past, both basic and applied research have been conducted on such
classical soil and water conservation topics as erosion control, sediment tran-
sport, soil chemistry and physics, crop production, range management, agricultural
chemicals, animal science, and forestry.  The challenge today is to locate,
interpret, and compile this past knowledge into forms useful for Section 208
planners.  This paper reviewed the current knowledge concerning the occurrence
of nonpoint pollution sources such as sediment, nutrients, pesticides, and fecal
contaminants.  Sediment transport equations were reviewed and described, and the
pollution potential of range and pasture livestock production was discussed.


78:050-068
SEDIMENT AND NUTRIENT CONTRIBUTIONS TO THE MAUMEE RIVER FROM AN AGRICULTURAL
WATERSHED,
Nelson, D.W., Monke, E.J., Bottcher, A.D., and Sommers, L.E.
Purdue University, West Lafayette, Indiana, Department of Agronomy.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 491-
505.  1 fig,  9 tab, 8 ref.

Descriptors:  Sediment discharge. Sediment load, Nutrient removal, Agricultural
watersheds, Agricultural runoff. Sediment transport, Water pollution, Water
quality, Water pollution sources, Indiana.

Total amounts of water, sediment, and nutrients discharged from two subwatersheds
of the Black  Creek study area (5000 ha) Allen County, Indiana, were determined
during 1975 and 1976.  Above average precipitation was experienced during 1975,
whereas 1976 was unusually dry.   From 400 to 3700 kg of sediment/ha/yr was lost
from the subwatersheds; land slope being the dominant factor in soil loss during
the wet year  and land use being the primary factor in drier year.  Most of the
total P transported was sediment-bound P, whereas a substantial proportion to
total N in discharge water was nitrate.  A few large rainfall events contributed
to the transport of a high proportion of sediment and sediment-bound nutrients;
whereas snow melt runoff accounted for disproportionally high transport of soluble
nutrients.  Surface runoff was the major source of sediment, sediment-bound
nutrients, ammonium N and soluble organic N and P transported from the subwater-
sheds.  A substantial proportion of soluble inorganic P was derived from septic
tank effluent in one subwatershed.  The relationship between fertility practices
in the subwatersheds and quality of water being discharged was discussed.  It
was concluded that the effects of agricultural nonpoint source pollution and
point source pollution on our water resources-are sufficiently different that
direct comparisons between them cannot be made.
                                     204

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                                       SECTION XXII


                        WATER QUALITY MANAGEMENT AND PROTECTION

                           EFFECTS OF POLLUTION (GROUP 05C)


 78:05C-001
 EFFECTS OF EVAPORATIVE SALT WATER COOLING TOWERS ON SALT DRIFT AND SALT
 DEPOSITION ON SURROUNDING SOILS,
 Wiedenfeld, R.P., Hossner, L.R., and McWilliams,  E.L.
 Texas A & M University, College Station, Texas Agricultural Experiment Station
 Journal of Environmental Quality, Vol. 7, No. 2,  p 293-298, April-June, 1978.

 Descriptors:  Cooling towers, Saline water, Saltation, Drifting (aquatic),
 Environmental effects, Texas.

 Five salt water cooling towers recently constructed near Galveston Bay, Texas,
 have been shown to contribute to salt deposition  in the surrounding area.
 Levels as high as 1,200 kg/ha per year of total salt were encountered within
 100 m of the towers, but decreased in a logrithmic fashion with distance to
  <300 kg/ha per year at 434 m with only 16% attributable to the cooling towers.
 The remaining deposition was caused by natural sea spray which varies widely
 but averages about 250 kg/ha per year in the study area.   Changes  in composition
 of air-borne salts with distance from the cooling towers were  noted,  primarily
 as a narrowing of the Na/Ca ratio.   Salinity levels  in the soil are in equili-
 brium with naturally deposited salts.   Enhanced salt deposition levels due to
 the cooling towers initially caused only slight effects  in the soils  closest
 to the towers, but may eventually lead-to both salinization and solonization
 in the surrounding vicinity.


 78:05C-002
 ON THE ESTIMATION OF THE  ANTHROPOGENIC POLLUTION  EFFECT ON THE FUNCTION STATE
 OF THE SOIL MICROFLORA,
 Gaponyuk,  E.I.,  and Kobzev, V.A.
 Institute  of Experimental Meteorology, Obninsk, Union  of  Soviet Socialist
 Republics.
 In:   Symposium on Environmental Transport and Transformation of Pesticides,
 October, 1976,  Tbilis,  USSR.  EPA-600/9-78-003, February,  1978,  Athens, Georgia,
 P  86-97.   2  fig,  2 tab, 13  ref.

 Descriptors:   Industrial wastes, Agricultural chemicals, Pesticides, Pesticide
 toxicity,  Environmental effects, Pollutants,  Soil microorganism. Soil micro-
 biology, Estimating.

 Experiments were  conducted  in Russia to estimate the anthropogenic pollution
 effect on  the  functional state of the soil microflora.   The dehydrogenase
 activity was chosen  as a criterion for evaluating the effect of  industrial and
 agricultural toxicants on the biological activity of soil microflora.  The
 toxic effect of high concentrations of heavy metals in soils of industrial
 regions was found  to be greater than that of pesticides.  The experimental re-
 sults indicate that  the toxic effect of chlororganic pesticides on the soil
 microflora may be  accounted for by the disturbance of the dehydration processes
which are of energetical value for the cell.  And the decrease  in the dehydrogenase
 activity may lead  to a decrease in the biotransformation processes associated
with it.


 78:05C-003
 INHIBITION OF PHOTOSYNTHESIS AND NITROGEN FIXATION IN ALGAE BY  VOLATILE NITROGBN
 BASES,
 Hosier, A.R.
 Agricultural Experiment Station, Fort Collins, Colorado.
                                     205

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 Journal  of  Environmental  Quality,  Vol.  7,  No.  2, p  237-240,  1978.   4  fig,  2 tab,
 20  ref.

 Descriptors:   *Nitrogen fixation,  *Anabaena  subcylindrica,  *Chlorella ellipsoidea,
 *Ammonia, *Photosynthesis,  *Amines, Aliphatic  amines, Feed  lots, Acetylene
 reduction,  Nitrogen.

 Inhibitory  effects  of  ammonia  and  amines on  oxygen  production by the  green alga
 Chlorella ellipsoidea  and the  nitrogen-fixing  blue-green alga Anabaena subcy-
 lindrica were  studied.  Objectives were to determine whether amines and ammonia
 affected:   (1)  oxygen  production in the algae  as in isolated plant chloroplasts,
 (2)  the  two algae differently,  or  (3) nitrogen fixation by A. subcylindrica.
 Aliphatic amines  (1-5  carbons)  and ammonia decreased C. ellopsoidea oxygen
 production  by  50% at concentration of 1.2-23.5 x 10 to the minus 9th  power micro-
 grams  free  amine N/cell and 160 x  10 to the  minus 9th power micrograms free
 ammonia  N/cell.  Amine (1-6 carbons) concentrations of 3.0-248 x 10 to the minus
 9th power micrograms free amine N/cell  decreased.   A subcylindrica oxygen pro-
 duction  and nitrogen fixation  50%, as estimated by  the acetylene reduction tech-
 nique.   Reduction of A. Subcylindrica oxygen production by 50% required ammonia
 concentrations  of 12-2510 times greater than any single amine concentration, and
 decrease of acetylene  reduction by 50%  required ammonia concentrations of 14-
 1220 times  greater.  The  effect of the  chemicals on C. ellipsoidea was reversible
 and depended on pH  and free amine  concentration.  Algae were axenically grown
 in  batch culture in flasks  containing Knopp's  solution adjusted to pH 7.2.


 78:050004
 NUTRIENT RUNOFF FROM FERTILIZED AND UNFERTILIZED FIELDS IN WESTERN CANADA,
 Nicholaichuk, W., and  Read,  D.W.L.
 Research Station, Research  Branch, Agricultural Canada, Swift Current,
 Saskatchewan S9H 3X2.
 Journal  of  Environmental  Quality,  Vol.  7,  No.  4, p  542-544, October-December,
 1978.  2 tab, 13 ref.
 (See 78:058-044)


 78:05C-005
 EFFECT OF SULFUR DIOXIDE  ON ALGAE,
 Wodzinski,  R.S., and Alexander, M.
 Ithaca College, New York, Department of Biology.
 Journal  of  Environmental  Quality,  Vol.  7,  No.  3, p  358-360, July-September,
 1978.  2 tab, 10 ref.

 Descriptors:  Algae, Air  pollution, Photosynthesis, Aquatic environment, Acidic
 soils, Air  pollution effects.

 Photosynthetic  activity in  soil of pH 7.1  was  unaffected by a 10-day exposure to
 0.5 ppm  sulfur  dioxide (S02) in air.  However,  the  photosynthetic activity of
 Anabaena flos-aquae and Chlamydomonas reinhardtii suspended in a thin layer of
 medium at an initial pH of  6.0 was almost  totally inhibited within 24 hours by
 treatment with  1.0 ppm S02  in air.  The pH of  the medium decreased to 5.2 or
 below during this period.    If the  decrease in  pH was prevented by the addition
 of  soil  or  phosphate buffer, no inhibition of  photosynthesis was observed.  In
 contrast, addition of an  acidic soil to a medium of pH 4.9 offered no protection
 from the adverse effects  of S02.   The data indicate that the decrease in pH of
 samples exposed to S02 was  not  the sole cause  of the inhibition of photosynthetic
activity.


 78:05C-006
HETEROTROPHIC UTILIZATION OF ORGANIC CARBON IN AQUATIC ENVIRONMENTS,
 Sayler, G.S.,  and Gilmour,  C.M.
 Tennessee University, Knoxville.
Journal of Environmental Quality,  Vol.  7,  No.  3, p  385-391, July-September, 1978.
 12 fig,  1 tab,  22 ref.

Descriptors:  Eutrophication, Aquatic environment.  Bacteria, Waste water,  Sewage,
 Respiration, Biomass, Trophic level, Water pollution,  Idaho.
                                     206

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 Field and laboratory investigations were performed to determine the contribution
 of dissolved organic carbon (DOC)  to the eutrophication process and its effect on
 heterotrophic bacterial activity.   Results indicated growth factors or vitamin
 limitations "Occurred in some aquatic samples-.   Significant responses to hetero-
 genous carbon substrates were detected at substrate concentrations commonly
 occurring in pristine, low DOC waters.  A direct linear relationship existed
 between heterotrophic activity and the concentration of available DOC.   Assuming
 no deficiency in other essential nutrients,  the DOC concentration was shown to
 regulate the rate and net response of heterotrophic bacterial  growth and activity
 in aquatic environments.  DOC levels were found to reflect net trophic  conditions
 unique to individual sampling locations,  thereby lending itself to assays for
 eutrophication assessment and pollution.


 78:05C-007
 THE IMPACT OF BROADLY APPLIED EFFLUENT PHOSPHORUS  STANDARDS ON EUTROPHICATION
 CONTROL,
 Gakstatter,  J.H.,  Bartsch,  A.F., and Callahan,  C.A.
 United States Environmental Protection Agency,  Corvallis Environmental  Reseach
 Laboratory,  Corvallis,  Oregon  97330.
 Water  Resources  Research, Vol.  14,  No.  6,  p  1155-1158,  December,  1978.   1  fig,
 18  ref,  1 equ.

 Descriptors:   Eutrophication,  Sewage effluents,  Effluents, Phosphorus,  Municipal
 wastes, Sewage disposal, Model studies, Trophic level, Water quality.

 The  potential trophic benefits  to  lakes and  reservoirs of a 1 mg/1 and  zero-
 discharge total  phosphorus  effluent standard for municipal sewage treatment plants
 were examined by using  two  phosphorus mass balance models.  The analysis included
 255  lakes and reservoirs receiving  municipal sewage treatment plant effluents and
 located in the eastern  half of  the  United States.  These water bodies, their
 significant  tributaries, and contributing effluents were sampled during the U.S.
 Environmental Protection Agency's National Eutrophication Survey.  Improvement in
 trophic condition  is  defined as a predicted decrease of at least 25% in external
 phosphorus supply, which would  cause  the predicted in-lake total phosphorus con-
 centration to (1)  decrease  from greater to less than 40 micrograms/liter but
 remain above  20  micrograms/liter,  (2) decrease  from above 20 micrograms/liter to
 less than 20  micrograms/liter,  or  (3) decrease from less than 20 micrograms/liter
 to a lower concentration.   Using the definition stated above,  the two models in-
 dicated that  18-22% of  the water bodies would benefit from a 1  mg/1 effluent
 standard.  If the  requirement were  zero phosphorus, 28% of the  water bodies would
benefit.
                                    207

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                                  SECTION XXIII


                   WATER QUALITY MANAGEMENT AND PROTECTION

                    WASTE TREATMENT PROCESSES (GROUP 05D)


78:050-001
EXTRACTABILITY OF 238PU AND 242 CM PROM A CONTAMINATED SOIL AS A FUNCTION OF PH
AND CERTAIN SOIL COMPONENTS:  HN03-NaOH SYSTEM,
Nishita, H., Hamilton, M., and Steen, A.J.
California University, Los Angeles, Laboratory of Nuclear Medicine and Radiation
Biology.
Soil Science Society of America Journal, Vol. 42, No. 1, p 51-56, January-
February, 1978.  3 fig, 3 tab, 37 ref.

Descriptors:  Soil contamination, Pollutants, Radioactivity, Nitrates, Organic
matter. Iron oxides, Hydrogen ion concentration, Silica, Ion exchange, Sorption.

The study involved an equilibrium batch technique using HN03-NaOH extracting
system.  The influence of various soil components on 238Pu and 242Cm extract-
ability was determined indirectly by selectively removing them from the soil.
Soil organic matter, free iron oxides, and free silica, alumina, and amorphous
alumino-silicates influenced the chemical e'xtractability of 238Pu and 242Cm.
The influence of these soil components depended on the pH of the soil suspension.
Below pH close to 4.5, 238Pu appeared to be more strongly sorbed on the mineral
fraction of the soil than 242Cm, but above pH close to 4.5, both were strongly
sorbed on the mineral fraction.  With the contaminated virgin soil, the 238Pu and
242Cm extractability ranged from 4.82 to 53.05% and 0.15 to 64.58% of dose,
respectively, depending on the pH of the extracting solution.  The lowest ex-
tractability occurred around pH 7.1 for 238Pu and in the range of pH 4.7 to 5.6
for 242Cm.
                                     208

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                                        SECTION XXIV

                           WATER QUALITY MANAGEMENT AND PROTECTION
                                    •

                              WATER QUALITY CONTROL (GROUP 05G)


 78:05G-001
 EFFECTS OF WETTING AGENTS ON WATER INFILTRATION INTO  WATER-REPELLENT COAL
 MINE SPOILS,
 Miyamoto,  S.
 Texas A &  M University,  El Paso, Research Center.
 Soil Science,"vol. 125,  No.  3,  p 184-187, 1978.   3 tab,  9 ref.

 Descriptors:   *Surfactants,  *Wetting,  *Strip mine  wastes,  "Infiltration,  •
 *Sulfonates,  Spoil banks, Revegetation,  Ethers,  Alcohols,  Effects.

 Improved water infiltration may enhance  revegetation  of  water repellent coal
 mine spoils.   Commercially available wetting agents,  therefore, were studied
 for their  effect on increasing  infiltration.   The  tested wetting  agents
 included linear sulfonate (anionic), alkyl polyethylene  glycol ether (nonionic),
 and ethoxolated alcohol  (nonionic)  compounds.   The infiltration tests'were
 performed  under greenhouse conditions  for soil as  well as water applied wetting
 agents.  Results indicated that in both  cases  the  sulfonate compound, but not
 necessarily the other, improves infiltration.


 78:05G-002
 PREVENTION OF  NITRATE LEAKAGE FROM THE HULA BASIN,  ISRAEL:  A CASE STUDY  IN
 WATERSHED  MANAGEMENT,
 Avnimelech, Y.,  Dasberg,  S.,  Harpaz, A.,  and Levin, I.
 Technion-Israel Institute of  Technology,  Haifa (Israel),    Department of Agri-
 cultural Engineering.
 Soil Science,  Vol.  125, No.  4,  p 233-239,  April, 1978.   4  fig, 2  tab, 17  ref.

 Descriptors:   *Watershed  management, *Nitrates,  *Leakage,  Leaching,  Nitrification,
 Drainage effects,  Water table,  Sprinkler  irrigation, Organic soils,  Crops.

 Drainage of the Hula basin led  to  the  exposure of  about  2,000 ha of organic soils.
 Corollary  to a high subsidence  rate, extensive nitrification and  leaching of
 nitrates became  evident,  endangering the  quality of the water in Lake Kinneret
 (Sea of  Galilee).  The problem  is being solved by  (1)  improving the drainage
 system and reducing water flow  through the basin;  (2)  maintaining a relatively
 high water table during the summer, thus minimizing the depth of the oxidized
 layer;  (3)  inducing denitrification through the use of sprinkler irrigation; and
 (4)  selecting  crops that  reduce  the accumulation of nitrates in the soil.


 78:05G-003
MEASUREMENT OF SEDIMENT CONTROL  IMPACTS ON AGRICULTURE,
Wade, J.C., and  Heady, E.G.
Arizona  University, Tucson, Department of Agricultural Economics.
Water Resources  Research, Vol. 14, No.  1, p 1-8, February, 1978.   2 fig,  5 tab,
 13 ref.

Descriptors:   *Sediment control, *Water pollution control, "Agriculture,  *Measure-
ment, Optimization, Linear programming, Land use, Mathematical models, Equations,
Systems analysis.

Environmental policy has been explicitly expanded in order to consider nonpoint
or dispersed sources of water pollutants.  This study  utilizes a national  agri-
cultural model to evaluate hypothetical policies of sediment control  viewing the
problem as  primarily a national  one of  agricultural land use.  A sediment  sector
is added to the basic Center for Agricultural and Rural Development National
                                    209

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 Water Assessment model to test the impacts of sediment control  policies  on  the
 agricultural production system.   Costs of alternative control policies are
 analyzed;  these costs are defined as the additional costs to agriculture of
 several alternative sediment'control policies.   Using linear programming, the
 minimum cost of the minimum feasible total sediment load is  determined,  a
 single restraint imposed at the national level.


 78:05G-004
 PLANNING DIFFUSE POLLUTION CONTROL:   AN ANALYTICAL FRAMEWORK,
 Schneider, R.R.
 Williams College,  Williamstown,  Massachusetts, Department of Economics.
 Water Resources  Research, Vol.  14, No.  2,  p 322-336,  April,  1978.   4  fig, 2
 tab,  39 ref.

 Descriptors:   *Planning,  *Water  pollution control,  Benefits, Costs, Analytical
 techniques,  Agriculture,  Optimum development plans, Systems  analysis, Evaluation.

 Determination of an optimal nonpoint pollution control strategy demands  informa-
 tion  relating to (1)  costs of pollutant reduction;  (2)  transport of pollutants;
 (3) water  quality  impact  of pollutants;  and (4)  the economic impact of water
 quality changes.   This paper briefly reviews the literature  in  each of these
 areas and  suggests an analytical framework useful  in  the development  of  an
 optimal nonpoint pollutant control strategy.


 78:050-005
 OVERVIEW OF  NITROGEN IN IRRIGATED AGRICULTURE,
 Rauschkolb,  R.S.
 California University,  Davis,  Cooperative  Extension.
 Proceedings  of National Conference on Management of Nitrogen in Irrigated
 Agriculture,  California University,  Sacramento,  California, p 53-60, May  15-
 18, 1978.  3  ref.

 Descriptors:   Water  quality.  Nitrogen,  Pollution abatement, Pollutant identifica-
 tion,  Fertilization, Water  management (applied),Irrigated land, Water law.

 Events  of  the recent past have been  moving  agriculture  rapidly  towards the
 point where  it can no  longer  afford  the  luxury of being  concerned with production
 of food and  fiber  alone.   One of  the principle reasons  for the  change in atti-
 tudes  has  been the Federal  Water  Pollution  Control Act Amendment of 1972,
 commonly referred  to as Public Law 92-500.  Within this  law  there is a section
 dealing with  areawide planning, Section  208.  Under this  section each state is
 to develop waste water  management strategies which indicate methods for control
 or treatment  of  all point and nonpoint  sources of pollution within an area.
 Specific outputs resulting  from Section  208  area-wide planning  include a regu-
 latory  program to  control or treat all point and nonpoint pollution sources,
 including  in-place or accumulated pollution sources.  This represents only one
 of the  many outputs that  are expected from area  208 planning, but it is one
 that  seems to  be the most  important with respect to nitrogen management in
 irrigated  agriculture.


 78:05B-006
 ECONOMIC IMPACTS OF CONTROLLING NITROGEN CONCENTRATION AND OTHER WATER QUALITY
 DETERMINANTS  IN THE YAKIMA  RIVER  BASIN,
 Pfeiffer, G.-H., and Whittlesey, N.K.
 North Dakota State University, Fargo, Department of Agricultural. Economics.
 Proceedings of National Conference on Management of Nitrogen in Irrigated
 Agriculture, California University, Sacramento, California, p 415-422, May 15-
 18, 1978.  4 fig,  4 tab, 9  ref, 2 equ.

 Descriptors:  Water quality, Nitrogen, Economic impact, Return  flow, Pollution
 abatement.

 The nonpoint source nature of water quality degradation caused  by irrigation
 return  flows makes control nearly impossible with traditionally effective
measures, such as limitations or  taxes on effluents.  As a consequence,  control
or taxation of those inputs to production which are involved in effluent input-
output relationships is a possible alternative.  In the Yakima  River Basin,  three

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 determinants of river water quality were identified:  nitrogen concentration,
 river water temperature, and soil erosion by irrigation water.  Among the
 pollution control policies considered for effectiveness, producer cost, and
 social cost were taxation of nitrogen fertilizer, increasing the charge for
 irrigation water, reduction of irrigation water rights, and restrictions on the
 types of irrigation systems used.  Results showed that policies which affect the
 level of one pollutant may or may not significantly affect the levels of others.
 Furthermore, policies taxing or charging for inputs, such as fertilizer and
 irrigation water, cause a substantial reduction in producer income if acceptable
 water quality is to be attained.   Therefore, water quality policy formulation
 and evaluation should consider the interactions which exist among water quality
 determinants and considerations of both the expected benefits of improved water
 quality and the level and distribution of improvement costs.


 78:05G-007
 SOURCES OF NITROGEN FOR CROP UTILIZATION,
 Murphy, L.S.
 Potash/Phosphate Institute,  Manhattan, Kansas,  Great Plains Director.
 Proceedings of National Conference on Management of Nitrogen in Irrigated
 Agriculture, California University,  Sacramento, California, p 61-107,  May 15-
 18,  1978.   23 tab,  40 ref,  2 equ.

 Descriptors:  Nitrogen, Fertilizers,  Crop production,  Nitrogen fixation,  Corn
 (field),  Soybeans,  Alfalfa,  Symbiosis, Ammonium compounds,  Irrigation  water.

 Nitrogen  fertilization of crops is essential for maximum food production.
 Nitrogen  from organic matter in the soil declines with continued  cultivation
 to the point that supplemental  nitrogen applications are necessary.  Supplemental
 sources of nitrogen for crop production include symbiotically fixed nitrogen
 from legumes,  nonsymbiotically  fixed  nitrogen from free-living organisms  in
 the  soil,  inorganic nitrogen from lightning  discharges and  industrial  emissions,
 industrially fixed  nitrogen  and nitrogen from various  waste products.   Recommenda-
 tions  for  nitrogen  applications in either dryland or irrigated agriculture are
 based  on  crop need  as  determined by agricultureJ- research.   Soil  analysis is  an
 important  tool in determination of needs.  Use  of present and future recommenda-
 tions  will  both maximize production of food  and maintain environmental  quality.


 78:05G-008
 NITROGEN FORMS  AND  CYCLING IN RELATION TO WATER QUALITY,
 Menzel, R.G.
 Water  Quality  Management Laboratory,  Science  and Education  Administration, U.S.
 Department  of Agriculture, Durant, Oklahoma   74701.

 Descriptors:  Water quality, Nitrogen,  Nitrogen  compounds,  Nitrogen cycle,
 Nitrogen fixation, Denitrification, Eutrophication.

 The  intended use of water determines  the  significance of various forms of
 nitrogen in water quality.  Upper  limit  concentrations have been recommended for
 several forms of nitrogen in water used  for public water supplies, freshwater
 aquatic life, marine aquatic life, and  agricultural uses.  The concentrations
 are  lowest for  cyanide,  and increase  in  the order ammonium, nitrite,  and nitrate.
 Nevertheless, nitrate is more often of  concern in water quality than are the first
 three  forms of  nitrogen.  Much of  the total nitrogen in surface waters occurs in
 particulate or  dissolved organic forms.  Plant growth is often excessive when
 the  total nitrogen concentration exceeds 0.5 mg/1 if other nutrients  are ade-
 quately supplied and growth conditions are favorable.  Nitrogen supply limits
 growth in many ocean areas and in a few lakes, mainly eutrophic ones.   Nitrogen
 fixation by blue-green algae tends to correct nitrogen deficiencies.   Denitrifi-
 cation by bacteria tends to correct excesses.  These features indicate that high
 nitrogen concentrations may be an effect, rather than a cause, of eutrophication.
78:05G-009
EVALUATION OF IRRIGATION METHODS FOR SALINITY CONTROL IN GRAND VALLEY,
Evans, R.G., Walker, W.R., Skogerboe, G.V.,  and Smitft, s.w.
                                    211

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 Colorado  State  University/ Fort  Collins,  Department of Agricultural and
 Chemical  Engineering.

 Descriptors:  Irrigation, Salinity, Saline soils, Water quality, Water loss,
 Water  pollution.

 Irrigation  return  flows  in the Upper Colorado River carry large salt loads as a
 result of contact  with the saline  soils and the marine derived geologic substra-
 tum.   The Grand Valley of western  Colorado is a major contributor to the salinity
 problems  of the basin and is, therefore,  a logical region to test the effective-
 ness of agricultural salinity control alternatives.  This study emphasized the
 implementation  of  on-farm salinity control alternatives; primarily evaluating
 irrigation  scheduling, furrow irrigation, sprinkler irrigation, and trickle
 irrigation. Border irrigation was also evaluated, but was not implemented as
 part of this study.  The cost-effectiveness of the various on-farm alternatives
 in the Grand Valley is summarized  and presented in this report.


 78:05G-010
 INTEGRATING DESALINATION AND AGRICULTURAL SALINITY CONTROL ALTERNATIVES,
 Walker, W.R.
 Colorado  State  University, Fort  Collins, Department of Agricultural and Chemical
 Engineering.
 Publication No. EPA-600/2-78-074,  April, 1978.  182 p, 30 fig, 17 tab, 55 ref,
 2 append.

 Descriptors:  Cost-effectiveness,  Desalting, Optimization, Salinity, Sprinkler
 irrigation, Water  quality.

 The cost-effectiveness relationships for various agricultural and desalination
 alternatives for controlling salinity in irrigation return flows are developed.
 Selection of optimal salinity management strategies on a river basin scale is
 described as a  problem of integrating optimal strategies with individual sub-
 basins  and  irrigated valleys.  Desalination systems include seven processes:
 (1) multi-stage distillation; (2)  vertical tube evaporation in conjunction with
 (1); (3)  a  vapor compression form  of (2); (4) electrodialysis,* (5) reverse
 osmosis;  (6) vacuum freezing - vapor compression; and (7) ion exchange.  Agri-
 cultural  salinity  control alternatives include conveyance linings, irrigation
 scheduling, automation,  sprinkler  irrigation systems, and trickle irrigation
 systems.  A case study of the Grand Valley in western Colorado is presented to
 demonstrate the analysis developed.  Results indicate that treatments of the
 agricultural system are  generally  more cost-effective than desalting except for
 high levels of  potential salinity  control.  Lateral linings and on-farm improve-
 ments  are the best agricultural  alternatives.


 78:05G-011
 IMPLEMENTATION  OF AGRICULTURAL SALINITY CONTROL TECHNOLOGY IN GRAND VALLEY,
 Evans,  R.G., Walker, W.R., Skogerboe, G.V.,  and Binder, C.W.
 Colorado  State  University, Fort  Collins, Department of Agricultural and Chemical
 Engineering.
 Publication No. EPA-600/2-78-160, July, 1978.  193 p, 62 fig, 29 tab, 46 ref.

 Descriptors:  Irrigation, Ditches, Irrigation canals, Salinity, Saline soils,
 Salt water, Seepage, Water distribution.

A summary of the results of applied research on salinity control of irrigation
return flows in the Grand Valley of Colorado -is presented for the period of
 1969 to 1976.   Salinity and economic impacts are described for the Grand Valley
Salinity  Control Demonstration Project which contains approximately 1,600
hectares  and involves most of the local irrigation companies in the Valley.
During the  eight years of the demonstration project, 12.2 km of canals were
 lined, 26.54 km of laterals were lined, 16,400 meters of drainage tile were
 installed, a wide variety of on-farm improvements were constructed, and an
 irrigation scheduling program was  implemented.  On-farm improvements evaluated
were solid-set sprinklers, side-roll sprinklers,  drip (trickle) irrigation,
furrow irrigation, and automatic cut-back furrow irrigation.  The total value
of the constructed improvements  in the demonstration area was about $750.000.
The total improvements resulted  in a salt reduction of 12,300 metric tons per
year reaching the Colorado River.  This salt reduction results in an annual

                                     212

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  benefit to downstream water users of nearly $2,000,000.  In addition, there are
  benefits to the local water users with increased crop yields, and to the neoole
  of Grand Valley in increased business.                                   ^  *


  78:05G-012
  SOCIO-ECONOMIC AND INSTITUTIONAL FACTORS IN IRRIGATION RETURN FLOW DMATTTV
  CONTROL VOLUME I:   METHODOLOGY,                                    WUAi,j.ix
  Vlachos, E.G., Huszar,  P.C., Radosevich, G.E., Skogerboe, G.V. ,  and Trock  W
  Colorado State University, Fort Collins, Colorado  80523.                '
  Publication No. EPA-600/2-78-174a, August,  1978.   132 p,  21 fig, 10 tab, 32 ref.

  Descriptors:   Water law, Water rights, Irrigation,  Irrigated land,  Water pollution
  W3.t61T CfUclllty •
  The purpose of this study has been to develop an effective process  for implement-
  ing technical and institutional solutions  to the problem of return  flow pollution
  The process developed:   a)  defines the problem in terms  of its  legal,  physical
  economic,  and social parameters;  b)  identifies potential solutions  in  relation'
  to  the parameters of the problem;  c)  assesses potential  solutions for  diverse
  situations;  d)  specifies those solutions or  groups of solutions which  are  the
  most effective in reducing  pollution and are implementable.  This process  is
  conceptualized in Volume I  of the  study.   The general results of its application
  are further presented in three separate volumes  concerning  the specific  case
  studies of  Yakima Valley (Washington) , Middle Rio Grande Valley (New Mexico and
  Texas) , and Grand Valley (Colorado) .


  78:05G-013
  SOCIO-ECONOMIC AND INSTITUTIONAL FACTORS IN  IRRIGATION RETURN FLOW QUALITY CONTROL
  VOLUME II:   YAKIMA VALLEY CASE STUDY,
  Huszar, P.C., Radosevich, G.E., Skogerboe, G.V. , Trock,  W.L. , and Vlachos, E.G.
  Colorado State University, Fort Collins, Colorado  80523.
  Publication  No. EPA-600/2-78-174b, August, 1978.  140 p,  19 fig, 12 tab, 113 ref
  1 append.                                                                       '

 Descriptors:  Water law, Water rights, Irrigation, Irrigated land,  Water pollution
 Water quality.                                               '                     '

 The goal of this research project has been to develop an  effective  process for
 implementing technical and institutional solutions to the problem of irrigation
 return flow pollution.  This report contains  the findings of a  case  study of the
 Yakima Valley, Washington.  The findings are  reported according to  the  proposed
 process,  namely:  a) defining the problem in  terms of its physical,  legal,  and
 economic,  and social parameters; b) identifying potential solutions  in  relation
 to the key parameters of the problem; c)  assessing the range of  potential solutions
 for  the specific area of concern;  and d)  specifying those solutions  or  groups of
 solutions  which are most effective in reducing pollution  and are implementable.
 The  basic  conclusions of the report are that:  a)  irrigation methods used in many
 parts of  the Valley are  inappropriate to  the  topography and soils, thus causing
 return flow pollution; b)  neither  state nor  federal  water  quality regulations
 have had a  significant impact on the pollution problem; c)  a major cause  of the
 problem is  the underpricing  of irrigation water caused by the absence of  economic
 markets  for  its  allocation;  d)  the  first step in solving  the problem is  the
 creation of  an economic  market to  allocate  irrigation water;  ej  perception and
 demonstration of  the problem are vital  for  any efforts to implement  any solutions;
 and  f ) holistic  thinking by  farmers regarding water in the Valley and individual
 acknowledgment of  contributions  to  the  problem are necessary to its  solution.


 78:05G-014
 SOCIO-ECONOMIC AND  INSTITUTIONAL FACTORS IN IRRIGATION RETURN FLOW QUALITY
 CONTROL VOLUME III:  MIDDLE RIO GRANDE VALLEY  CASE STUDY,
 Trock, W.L., Huszar, P. C. , Radosevich, G.E., Skogerboe, G.V. , and Vlachos, E.G.
 Colorado State University, Fort Collins, Colorado  80523.
 Publication No. EPA-600/2-78-174c, August, 1978.  137  p,  14 fig, 15  tab, 146 ref,
 2 append.

 Descriptors:  Water law,  Water rights, Irrigation/ Irrigated land, Water pollution,
Water quality.


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 Degradation of water quality as a consequence of use in irrigation in the Lower
 Rio Grande Valley of New Mexico is a largely unavoidable phenomenon.   In this
 region, annual allocations of water to irrigated farms,  about 2.5 acre-feet per
 acre,  are little more than enough to produce crops.   Evaporation and  transpiration,
 occurring because of irrigation, cause concentrations of salts in return flows
 to be  greatly increased, and the addition of these highly saline return flows
 to a quite limited flow of water in the Rio Grande causes the quality of the
 river  water to be significantly reduced.   It is possible to affect the quantity
 and quality of return flows by improvement of water transport facilities (canals,
 laterals  and ditches)  and by improved management of water on some farms.  These
 two technical improvements can be accomplished by extension of technical assistance
 through existing federal and state agencies and by cost-sharing programs such as
 the Agricultural Conservation Program.  But it is also  possible to achieve im-
 proved management of water on farms by facilitating exchanges or sales of allot-
 ments  among farmers who are members of irrigation districts.   Such transfers
 ordinarily result in improved use of water, i.e., a more conservative use of
 water  and employment of this scarce input in higher-valued uses.  The consequence
 is some reduction in return flows and thus improvement  in the quality of water
 in the Rio Grande River.


 78:05G-015
 SOCIO-ECONOMIC AND INSTITUTIONAL FACTORS  IN IRRIGATION  RETURN FLOW QUALITY CONTROL
 VOLUME IV:  GRAND VALLEY CASE STUDY,
 Skogerboe, G.V.,  Huszar, P.C.,  Radosevich, G.E.,  Trock,  W.L., and Vlachos, E.G.
 Colorado  State University,  Fort Collins,  Colorado  80523.
 Publication No.  EPA-600/2-78-174d,  August, 1978.   139 p,  17 fig, 14 tab, 39 ref,
 2  append.

 Descriptors:   Water law, Water  rights, Irrigation,  Irrigated  land,  Water pollution/
 Water  quality.

 The Grand Valley  was used as a  case study area for developing an effective process
 for implementing  technical  and  institutional solutions  to  the problem of pollution
 from irrigation return flows.   This area  is the most significant agricultural
 salt source in the Upper Colorado River Basin.   The  primary source  of salinity
 is from the extremely  saline aquifers overlying the  marine deposited  Mancos
 Shale  formation.   Subsurface irrigation return flows resulting from conveyance
 seepage losses  and overirrigation of  croplands dissolve  salts from  this  formation
 before returning  to the Colorado River.   The most cost-effective technologies
 for reducing the  salt  load  are  a combination of lateral  lining and  on-farm
 improvements.   Farmer  participation in such a program is very important.  Imple-
 mentation will  result  in excess water being available for  selling,  renting,  or
 leasing to water  users upstream from  Grand Valley.


 78:05G-016
 ECONOMIC  IMPACT OF  WATER QUALITY ON RIVER BASIN MANAGEMENT,
 Helweg, O.J., and Alvarez,  D.
 California University,  Davis, Department  of Civil Engineering.
 California Water Resources  Center,  Davis,  Completion Report,  Contribution 168,
 March, 1978.  61 p,  47  fig,  16  tab, 47  ref.

Descriptors:  *Groundwater,  *Irrigation,  *Water quality, *Water  costs, 'Economic
 impact, California, *San Luis  River basin  (California), Irrigation practices,
Saline water, Pricing, Water demand, River  basin management, Water pollution.

Groundwater quality degradation caused by  irrigation affects as much as  one-third
of the irrigated area of the world.  This problem is particularly insidious be-
cause the  process is slow and hidden.  A management  tool called  the Accelerated
Salt Transport  (ASTRAN) method  has  recently been proposed to help control ground-
water degradation.  The ASTRAN method distributes the different  qualities of
available   irrigation water over the basin in a way that controls groundwater
degradation at minimum cost.  To implement  the solution, the water supplier must
give some   irrigators poorer quality water than others.  If water is sold merely
by the quantity used, irrigators who receive the poor quality water will certainly
object; consequently, the price of water should be determined by water quality as....
well as quantity.  This study investigated a way to price water quality  and quantify
by approximating its value with a derived demand surface.  This value was then used


                                     214

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   In Q  *u   S °Ptimally distributed water.  The data from the San Luis RivPr R
   In southern California were used to test the results which are presented in a
   series of figures along with a detailed description of the approach Ssed.


   78:05G-017
   NORTH CAROLINA 208 CASE STUDY,
   Jrrnev'  L.F.,  Koehler,  F.A.,  and Bliven,  L.F.
   "Orth Carolina S-t-at-o TTm' TTQ vai -l-if  Dala'i^Vi   n^v,., »-4-m,,_ j. -f  nj_i_  j   ,    ,
                                                        or  Biological  and
  ^aper No.  78-2584,  Presented at  the  1978  Winter Meeting  of  the  American
  Ulinois,  6  p.   4 ref.    '                ,      ,  a mer  House Hotel,  Chicago,
  (See 7S:06E-009)


  78:05G-018
  EFFECT OF DRAINAGE  SYSTEM DESIGN AND OPERATION ON NITRATE TRANSPORT
  jKaggs, R.w., and Gilliam, J.W.
   orth Carolina State University, Raleigh, Department of Biological and
  Agricultural Engineering.
  £aper No.  78-2501, Presented at the 1978 Winter Meeting of the American Societv
  "f Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicaan
  Illinois,  13 p.  9 fig, 3 tab, 18 ref, 4 equ.                             g '

  Descriptors:  Water pollution, Nitrates, Water quality, Simulation analysis,
  dr tnage e^^ects, Drainage systems, Drainage density,  Drainage water,  Surface
  Drainage,  Subsurface drainage.

  s^™ulations were conducted to predict N03(-)  movement  from artificially drained
  Noi";8'   Effects of alternative drainage designs  and operational  procedures on
    3(~) outflow to drainage waters were presented.


  78:05G-019
  NONPOINT SOURCE  CONTROL GUIDANCE, AGRICULTURAL ACTIVITIES,
  •"-nronson, R.E.
  ^nited states  Environmental Protection  Agency, Washington, D.C., Water  Planning

  3T^S/PB~280/845,  EPA-440/3-78-001,  February,  1978.  147 p.  40 fig, 8 tab, 101 ref,


               Water pollution, Water pollution control, Water quality, Water
         control, Water pollution sources, Sediment discharge, Agricultural
         "  Salinity, Grazing, Waste disposal.
      publication presents technical and management guidance information regarding
      em identification and assessment, information needs and analyses, and best
  anagement practices (BMP's)  to provide state and areawide water quality management
  yencies and other concerned groups with assistance in the development and imple-
  entation of programs to control nonpoint sources of pollution.


 78:05G-020
  PPECT  OF SALINITY ON AGRICULTURE IN IRAQ,
 Al-Layla,  M.A.
  °sul University,  Iraq,  Department of Engineering.
  ournal  of the  Irrigation and  Drainage Division,  American  Society of Civil
 engineers,  Vol.  104,  No.  IR2,  p 195-207,  June,  1978.   2  fig,  3 tab, 3  ref,  1 append.

 wa?Crlptors:  Salinity, Agriculture,  Irrigation effects, Return  flow,  Drainage
  ater, Water quality  control,  Water pollution,  Asia.
Jfffgation has progressed considerably in Iraq, but it has resulted in soil
£a-i-inity thereby reducing the productivity of the agricultural lands.  Land has
wafn reclaimed by taking up drainage projects, but the discharge of the drainage
water into the river has considerably increased the salinity of the river water
fusing deterioration in its quality.  The increase in salinity of  river  water creates
Problems for irrigation and municipal uses, and therefore, the discharge of drainage
                                         215

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water to the river must be controlled.  To obtain maximum benefit from the use of
land and water resources, the problems of irrigation, drainage, control of river
water quality, and education of farmers must be tackled as a whole and not in
parts.


78:05G-021
A RATIONAL APPROACH FOR OPTIMIZING APPLICATION RATES OF FERTILIZER NITROGEN TO
REDUCE POTENTIAL NITRATE POLLUTION OF NATURAL WATERS,
Singh, B., Biswas, C.R., and Sekhon, G.S.
Punjab Agricultural University, Ludhiana 141004, India, Department of Soils.
Agriculture and Environment, Vol. 4, No. 1, p 57-64, April, 1978.  3 fig, 2 tab,
6 ref.

Descriptors:  Nitrogen, Fertilizers, Nitrates, Pollutants, Pollution abatement,
Water pollution control, Wheat, Sweet corn, Crop response, Leaching, Crop
production.

Yield, N uptake and residual N03(-)-N data for wheat and maize, raised in a long-
term experiment, have been discussed to determine optimum rates of fertilizer
N application at which yields are least affected, while unused nitrogen, which
is a potential pollutant, is reduced to a permissible level.  Computation of
fertilizer N rates corresponding to the points of greatest economic return and
permissible N loss has been described.  Optimum fertilizer N rate-is the smaller
of the two fertilizer N rates.  By assuming a loss of 60 kg N/ha or less, as
environmentally permissible, it was observed that a small yield increment of
maize would have to be sacrificed for the protection of the environment? whereas,
for wheat, nitrogen can be applied safely up to the point of greatest economic
return.  Coincidence of the rainy season with the growth period of maize in the
study area seems to have reduced the fertilizer N rate, corresponding to the
point of permissible N loss, lower than that for greatest economic return.


78:056-022
AGRICULTURE AND SALINITY,
Gardner, B.D., and Stewart, C.E.
Values and Choices In the Development of The Colorado River Basin, The University
of Arizona Press, Tucson, Arizona, 1978, p  121-143;  7 fig, 4 tab, 14 ref.

Descriptors:  Colorado River, Colorado River Basin, Return flow, Water quality
act, Water quantity control, Water pollution control, Water pollution sources,
Salinity, Mexican water treaty.

This paper discusses the saline return flow problems of the Colorado River due
to irrigated agriculture of the Colorado River Basin.


78:05G-023
FINANCING REGIONAL DRAINAGE FACILITIES UNDER 1978 ECONOMIC CONDITIONS,
Johnston, W.R., and Beck, L.A.
Westlands Water District, P.O. Box 5222, Fresno, California  93755.
Paper No. 78-2535, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 12 p. ' 3 fig, 3 tab.

Descriptors:  Drainage problems, Drainage, Financing, Saline water, Salinity,
California, Cost-benefit analysis, Crop production, Surface drainage. Subsurface
drainage.

The benefits, costs, and a recommended financial program to solve saline drainage
problems on over 400,000 hectares (1,000,000 acres) of irrigated land in the San
Joaquin Valley of California, USA, are discussed.  The heed to provide long-term
financing for major drainage facilities is demonstrated.
                                      216

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 78:050-024
 APPLICATION OF LAND TREATMENT FOR WATER QUALITY IMPROVEMENT,
 Wheaton, R.2.
 Purdue University, Lafeyette, Indiana, Department of Agricultural Engineering.
 Paper No. 78-2533, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 3 p.

 Descriptors:  Water quality control, Water quality, Land management, Control
 structures, Cultural control, Soil conservation, Pollution abatement, Agricultural
 watersheds, Small watersheds, Water law.

 Application of Land Treatment measures is considered to be a means of controlling
 Agricultural Non-Point Pollution.   Experiences gained during a demonstration
 project of these principles is reviewed.  The problems of absolute water quality
 standards and monitoring for compliance of non-point pollution are discussed and
 alternatives suggested.


 78:05G-025
 AGRICULTURAL DRAINAGE PROBLEMS IN  KERN COUNTY, CALIFORNIA,
 Rector,  M.R.,  and Donnan,  W.W.
 Kern County Water Agency,  Bakersfield,  California.
 Paper No. 78-2532, Presented at the 1978 Winter Meeting of  the American  Society
 of Agricultural  Engineers, December 18-^20,  1978,  Palmer House Hotel,  Chicago,
 Illinois, 15 p.   3 fig.

 Descriptors:   Drainage, Drainage area,  Tile drainage,  Crop  production. Perched
 water,  Salinity,  Drilling, Water quality,  Water table,  California.

 This paper describes  procedures followed in the diagnosis,  monitoring and  evaluation
 of the  drainage  problem areas within. Kern County, California as a  case history
 for use  by others who are  facing these  same problems.


 78:05G-026
 SUBSURFACE DRAINAGE SYSTEMS INSTALLATIONS IN ARID LANDS—THE STATE OF THE ART,
 True, G.
 Advanced  Drainage Systems, Incorporated,  Fresno, California,  Department of
 Agricultural Engineering.
 Paper No.  78-2528,  Presented  at  the 1978  Winter Meeting of  the American Society
 of Agricultural Engineers, December 18-20,  1978, Palmer House Hotel,  Chicago,
 Illinois,  2 p.

 Descriptors:   Subsurface drainage,  Drainage, Installation, Arid lands. Equipment,
 Materials, Trenches, Grading,  Maintenance,  Irrigated land.

 Agricultural drainage  contractors are quickly  adapting to new techniques and
 equipment  that result  in better  and more efficient drainage  systems.  The.se
 relatively inexpensive  drainage  systems are maintaining the  long-term viability
 of irrigated agriculture and  increasing crop yields far above the value of energy
 and capital invested in drainage.


 78:05G-027
 DESIGN AND OPERATION OF GRADIENT TERRACE SYSTEMS,
 Bondurant, D.T., and Laflen, J.M.
 Soil Conservation Service, Des Moines, Iowa.
 Paper No. 78-2520, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 7 p.  4 fig,  5 tab, 19 ref.
 (See 78:02J-006)


 78:05G-028
 GROUNDWATER AND SALINITY IN THE GRAND VALLEY OF COLORADO,

United states Department of Agriculture, Science and Education Administration,
Agricultural Research, Fort Collins, Colorado.


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Paper No. 78-2530, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 21 p.  5 fig, 3 tab, 14 ref.

Descriptors:  Salinity, Saline water, Saline soils, Salts, Groundwater, Water
management  (applied), Colorado, Colorado River, Colorado River Basin, Structures.

This paper describes causes and magnitudes of groundwater flows and salt loading
in the Grand Valley in western Colorado.  Structural measures and management
practices most likely to reduce salt loading are described.


78:05G-029
PLANT NUTRIENT LOSSES FROM FOLIAR-FERTILIZED SOYBEANS,
Baker, J.L., and Laflen, J.M.
Iowa State University, Ames, Department of Agricultural Engineering.
Paper No. 78-2084, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 11 p.  5 fig, 1 tab,
4 ref.

Descriptors:  Fertilization, Nutrient removal, Nutrients, Foliar application,
Water quality, Runoff, Foliar, Soybeans, Simulated rainfall, Corn (field).

To determine the impact of foliar-fertilization of soybeans on runoff water
quality, simulated rainfall was applied to soybeans and corn receiving no
fertilizer and to soybean plots foliar-fertilized  (20 kg/ha N, 2 kg/ha P) 39
and 13 hr before rainfall.  Washoff water from plants and surface runoff water
were analyzed for NH4-N, N03-N, total N, PO4-P, and hydrolyzable-P.  Foliar-
fertilization did initially increase concentrations of dissolved nutrients in
runoff, but most N and P washed from plants was retained by the soil within
plot areas.


78:05G-030
TRANSPORT CHARACTERISTICS OF PHOSPHORUS IN CHANNELIZED AND MEANDERING STREAMS,
Rosendahl, P.C., and Waite, T.D.
United States National Park Service, South Florida Research Center, Everglades
National Park, Homestead, Florida  33030.
Water Resources Bulletin, Vol. 14, No. 5, p 1227-1238, October, 1978.  4 fig, 1 tab,
20 ref, 7 equ.

Descriptors:  Nutrients, Phosphorus, Water quality, Meanders, Channeling,
Phosphates, Surface runoff, Dispersion, Mathematical models, Plankton.

Comparisons were made between rates of movement of orthophosphate in a canal
and a meandering stream.  The meander stream had greater algal and macrophyte
phosphate uptake rates, and lower plankton and sediment release rates compared
to the canal.  Chemical precipitation and direct rainfall influences on
orthophosphate movement were insignificant relative to other terms.   The major
source of phosphorus to both systems was from upland runoff.  The impact of this
source was greater on the meandering system due to the smaller channel volume.
When secondary effects of meandering were considered such as march inundation,
the net orthophosphate movement within the meandering channel was less than that
for the canal; due to the lower concentrations of phosphorus in march effluent
waters.  Field experiments were conducted to compare the longitudinal dispersion
coefficient between a canal and meandering river system; the meandering stream
had a dispersion coefficient over 17 times that measured for the canal.  Rates
of orthophosphate movement were combined into a single mass transport equation,
and a numerical solution was obtained.  Internal river and canal'channel processes
were overshadowed by external point source loadings.


78:05G-031
A PARTITIONING PROCEDURE FOR WATER QUALITY MANAGEMENT MODELS,
Rossman, L.A., and Vanecek, F.T.
Environmental Protection Agency, Cincinnati, Ohio.
Water Resources Bulletin, Vol. 14, No. 4, p 842-855, August, 1978.  2 fig, 2 tab,
25 ref.
                                      218

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Descriptors:  *Water quality,  *Management, *Economic efficiency, *Partitioning
procedure, *0ptimization,  Thermal pollution, Decision making,  Standards, Water
temperature, River systems,  Dissolved oxygen. Biochemical  oxygen demand,
Mathematical mqdels, Systems analysis. Equations,  Cooling  levels, Stream
response. Nonlinear programming, Gradient search procedure.

An improved computational  procedure for solving water quality  management models
containing interacting pollutants and control policies is  presented.  The method
is developed with respect  to the specific problem of minimizing the costs of
basin-wide thermal and organic pollution control to meet water quality standards.
It views the problem in partitioned form where a master problem is sued to find
cooling levels for thermal polluters while subproblems determine optimal organic
pollutant reductions for fixed cooling levels.  A gradient-based search procedure
is used to solve the master  problem.  Computational results  for several river
systems are presented.  Application of the method to other water quality manage-
ment models should improve computational efficiency and make the use of such
models more attractive to  basin planners.



IMPROVING3 IRRIGATION RETURN  FLOW QUALITY WITH A WATER RENTAL MARKET,

SloradoPStatea!toi?SSty!!'Fort Collins, Department of Economics.
Water Resources Bulletin,  Vol. 14, No. 4, p 978-987, August, 1978.  3 fig, 1 tab,
5 ref.

Descriptors:  'Irrigation. 'Return flow, 'Water quality, 'Improvement, 'Rental
market  Water transfer  Water  allocation  policy), River systems, Effects,
?osts%a?er pollulfon! Conceptual model , Yakima Valley (Washington), Systems
analysis.

Current policies for correcting the problem of irrigation  return flow pollution
tend to  ttack the symptoms  of t he problem ^*™     aslhe* ou^ce
     eroem                          wate  quality benefits of altering


33 s-sass.psis j s     H r%ss-^cS s^^r^^^"
and rent the surplus *°°^t,l market ciuld Improve »lter quality In the Yakima
crop production.



AN CATION OF THE POTENTIAL FOR USING DRAINAGE CONTROL TO REDUCE NITRATE LOSS
FROM AGRICULTURAL FIELDS TO SURFACE WATERS,

                    '4~£J!$£ 5S2SS o«  Soil sc^e.

                £SS£ ISJt^S P! *S SST « «S-  32 -f, 2 appen*.
„             u.   j        ,,4-wvi   **Mtrates. 'Soil water movement, 'North Carolina,
Descriptors: /Drainage control,  Citrates,   Denitrification, Agricultural
Nitrogen, Agricultural soils,  Surrace watej-o,
runoff, Soil drainage, Coastal plain sons.
                         ,.v   * *,v.a,Hmi<* work which revealed that considerable
This study was. an outgrowth  of Pfev*°uf *f *JJs £ith high water tables.  This
denitrification occurred in  poorly araineu    ,      waters than occurred in better
resulted in less nitrate leaving  "~JS TV I were used:  one in the poorly drained
drained soils.   Two  N.C. CoaBt"  *£ „£,."  in the moderately well drained soils of
soils of the Tidewater area  and the other  type water control stuctures were
the Lower Coastal Plains,  ^"^f1 J^ Ration.  Each control structure was
installed in four main tile  lines at eacn ioc      ti  total outfiow of drainage
equipped with a weir and a stage  x*°°™?*t     installed at each weir to take
water.  A semi-proportional  watei .falructures were very effective in controlling
samples for chemical analyses.  The struc u         drained soils.  The annual
the loss of nitrate-nitrogen on the moderately wex
                                    219

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loss of nitrate-nitrogen under controlled conditions was 1-7 kg/ha as compared
to the 25-40 kg/ha under uncontrolled conditions.  This reduction is due entirely
to prevention of water movement through the tile lines, however, and there is no
indication that the water control resulted in the anticipated increased denitrifi-
cation in the fields.  Water table control on the poorly drained soils was much
more successful.  By controlling and maintaining the water table at higher levels,
no significant difference in oxidation-reduction potential throughout the soil
profile was observed.  Also, there was no significant change in the nitrogen
concentration in water leaving the fields in the drainage ditches under
controlled and uncontrolled conditions.


78:05G-035
SALINITY MANAGEMENT OPTIONS FOR THE COLORADO RIVER, DAMAGE ESTIMATES AND CONTROL
PROGRAM IMPACTS,
Andersen, J.C., Kleinman, A. P., Brown, F.B., Cannon, J.R., and d'Arge, R.C.
Utah Water Research Laboratory, Logan.
Water Resources Planning Series Report P-78-003, June, 1978, 344 p.  53 fig, 365
tab, 7 append.

Descriptors:  *Economic efficiency, *Resource allocation, *Salinity, *Agricultural
damages, *Alternative costs, *Colorado River, Regional analysis, Water quality,
River basins, Water management  (applied), Estimating, Costs, Economic impact,
Input-output analysis.

Rivers draining arid basins increase in salinity content in the downstream area of
the point where water users are often significantly damaged.  The problem in some
cases can be ameliorated by altering upstream water and land use practices .  An
economic trade-off exists between the cost of such upstream efforts and the down-
stream benefits achieved.  This study sought to provide additional information
to estimate  (1) economic and  (2) economic costs of salinity control measures by
upstream water users.  Damages were estimated for high salinity levels to provide
guidelines to project future conditions.  Control costs were estimated with a
physical model developed to predict the response of soil, water, and crop factors.
Input-output models were used to estimate indirect economic impacts.


78:05G-036
EFFICIENT AMENDMENT USE  IN  SODIA SOIL RECLAMATION,
Prather, R.J.,  Goertzen, J.O.,  Rhoades, J.D., and Frenkel, H
Institute of  Soils and Water, Volcani Center, P.O. Box 6, Bet Dagan, Israel.
Soil  Science  Society of America Journal, Vol. 42, NO.  5, p  782-786,  September-
October, 1978.   8 fig,  5 tab, 9 ref.                                  r

Descriptors:   Reclamation,  Alkali  soils,  Soil amendments, Calcium  sulfate,
Gypsum,  Calcium chloride, Sodium,  Leaching,  Regression analysis.

A laboratory  column  study of  sodic  soil reclamation was carried out  using  two
 soils high  in exchangeable  sodium  percentage (ESP) and cation exchange  (CEC) .
Three amendments (CaS04-2H20, CaC12«2H20, and H2S04)  were used  singly and  in
combination to test  their effectiveness and efficiencies with respect to amount
of amendment,  tine,  and leaching needed.  As a  single amendment,  H2S04 was  found
 to be more  effective than CaS04 and results in  a more desirable ESP  profile  than
CaC12.   Combining either CaC12  or  H2S04 with CaS04  (proportions of 1/4  and  3/4,
 respectively)  appreciably reduced  the  time  and  leaching needed  to achieve
 reclamation as compared with CaS04 alone,   it was  observed  that certain  soil
 conditions  preclude  or make undesirable  the use of CaS04  alone  and combinina
 amendments  results in effective reclamation and a  potential savSgs
 costs.


 78:05G-037

                                    SED1MENT DISCHARGES IN RUNOFF  FROM OKLAHOMA
 CRDRAAD
 Menzel, R.G., Rhoades, E.D., Olness, A.E., and Smith  S J
 Agricultural Research Service, Durant, Oklahoma, Water Quality Management Laboratory.
 Journal of Environmental Quality, Vol. 7,  No.  3, p 401-406,  1978   I fig? 4 tab?
 22 ref.
                                      220

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Descriptors:  *0klahoma, *Fertilizers, *Nutrients, *Agricultural runoff, *Sediment
yield, *Water quality, *Soluble nutrients, Nitrates, Agricultural chemicals,
Water pollution sources, Nitrogen compounds, Nitrogen> Phosphorus, Soil properties.
Water pollution, Rainfall, Soil erosion, Sediments, Pollutants.
                                   \
Nitrogen and phosphorus discharges in runoff from nearly level cropland and 3%
sloping rangeland were measured from July 1972 to June 1976.  Sediment discharges
and runoff amounts from these 5- to 18-ha watersheds were measured from July 1966
to June 1976.  Sediment and nutrient discharges varied greatly from year to year
and between different land uses.  It was concluded that long records are needed to
compare discharge from different management practices.  The average and maximum
annual sediment discharges, respectively, were 3,600 and 8,900 kg/ha from irrigated
cotton, 900 and 3,900 kg/ha from dryland wheat, 400 and 1,800 kg/ha from range
with limited grazing, and 9,000 and 23,000 kg/ha from overgraze range.  Maximum
annual sediment discharges occurred during the period in which nutrient discharges
were measured.  Maximum annual nutrient discharges were 13 kg/ha total N, 4 kg/ha
nitrate N, 11 kg/ha total P, and 2 kg/ha soluble P.  The average annual discharge
for each nutrient form and land use was about half of its maximum value.  Nitrate
accounted for 10 to 30% of the total N discharged.  Soluble phosphate accounted
for about 20% of the total P discharged from cropland and less than 10% of that
discharged from rangeland.  Annual deposition in rainfall averaged kg/ha N and 0.15
kg/ha P.


78:05G-038
IRRIGATION WATER SALT CONCENTRATION INFLUENCES ON SEDIMENT REMOVAL BY PONDS,
Robbins, C.W., and Brockway, C.E.
Agricultural Research Service, Kimberly, Idaho, Snake River Conservation Research
Center.
Soil Science Society of America Journal, Vol. 42, No. 3, p 478-481, May-June, 1978.
2 fig, 2 tab, 12 ref.

Descriptors:  *Sediment control, *Irrigation, *Salts, Irrigation return flow,
Ponds, Water treatment, Coagulation, Flocculation, Runoff, Sediments, On-site
investigation, Laboratory tests, Irrigation water, Irrigation practices, Sedimen-
tation.

Irrigation water salt concentration effects on sediment pond efficiency were
investigated to demonstrate the necessity of considering the salt concentration
in the irrigation waters when designing sediment retention ponds.  The influence
of dissolved salt was determined by adding concentrated CaC12 solutions to three
ponds and then measuring electrical conductivities and sediment concentrations
at the pond outlets.  Increasing the salt concentration increased the sediment
removal efficiencies when the retention time in the pond exceeded 1 hour or the
inflow sediment concentration exceeded 500 ppm for the three soils studied.
Adding salt to laboratory soil sample suspensions increased the settling rates
for the two soils studied.  That data indicated that the salt concentration in
irrigation water is an important factor in determining sediment pond size and
retention time.  Using pond design criteria obtained from sediment ponds receiving
water of a given salt concentration to design ponds that will receive water with
a different salt concentration should include adjustments for salt concentration
differences.  A simple laboratory test was suggested to predict which soils will
respond to irrigation water salt concentration changes that are likely to result
in sediment pond efficiency changes.


78:05G-039
DEVELOPMENT OF MANAGEMENT GUIDELINES TO PREVENT POLLUTION BY IRRIGATION RETURN
FLOW FROM RICE FIELDS,
Brown, K.W., Deuel,  L., Price, J., DeMichele, D., and Teague, W.R.
Texas A & M University, College Station, Texas.
Publication No. EPA-600/2-78-082, April, 1978.  570 p, 147 fig, 78 tab, 170 ref,
15 append, 96 egu.

Descriptors:  Water management {applied), Water quality control,  Water quality,
Return flow, Water pollution control,  Rice,  Irrigation practices, Fertilization,
Ion transport, Computer programs.
                                       221

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A  three-year  field and  laboratory study was conducted to determine the influence
of management practices on the quantity and quality of irrigation return flow
from rice  paddies.  Continuous and intermittent irrigation techniques were used
on replanted  field plots which received either recommended or excessive applications
of fertilizer and four  selected pesticides.  Water quality was evaluated with
respect  to fertilizer amendments, pesticides, pH and total salt load.  Pesticides
monitored  included propanil molinate, carbofuran, carbaryl and their respective
metabolites.  Present water management practices result in large return flow volumes.
Occasionally  concentrations of NH4 exceeded drinking water standards.  Losses of
nitrate  were  below such limits and the total nitrogen losses were a small fraction
of the fertilizer applied.  A model was developed to simulate the ionic constitericy
of the return flow.  Propanil was washed from the foliage into the flood water and
dissipated within 24 hours.  Evidence is given that carbaryl is washed from the
leaves by  rainfall, thus providing available source to contaminate return flow.
As long  as 8  days were required to dissipate residue resulting from recommended
applications.  Retention times to assure low concentrations in the irrigation
return flow for carbofuran are of the order of 16 days.  Granular applied molinate
necessitates  a retention time of 4 days to assure concentrations are within 10%
of the TLM to fish.  It is suggested that through improved water management and
knowledge  of  dissipation rates, the quanity of irrigation return flow can be
reduced  and the quality improved.


78:05G-040
TIMING AND RATE OF FERTILIZER NITROGEN FOR SUGARBEETS RELATED TO NITROGEN UPTAKE
AND POLLUTION POTENTIAL,
Hills, F.J.,  Broadbent, F.E., and Fried, M.
California University, Davis, Department of Soil Microbiology.
Journal  of  Environmental Quality, Vol. 7, No. 3, p 368-372, July-September, 1978.
4  fig, 3 tab, 11 ref.
(See 78:021-030)


78:05G-041
THE PESTICIDE CONTENT OF SURFACE WATER DRAINING FROM AGRICULTURAL FIELDS—A REVIEW,
Wauchope,  R.D.
Southern Weed Science Laboratory, Science and Education Administration, Federal
Research,  United States Department of Agriculture, Stoneville, Mississippi  38776.
Journal of  Environmental Quality, Vol. 7, No. 4, p 459-472, October-December, 1978.
3  fig, 4 tab, 69 ref.
(See 78:10C-003)


78:05G-042
LEACHING,OF CATIONS AND CHLORIDE FROM MANURE APPLIED TO AN IRRIGATED SOIL,
Pratt, P.P.
California  University, Riverside, Department of Soil Science.
Journal of  Environmental Quality, Vol. 7, No. 4, p 513-516, October-December, 1978.
3  fig, 15  ref, 8 equ.

Descriptors:  Leachate, Leaching, Organic wastes, Cations, Chlorides, Irrigation,
Water pollution, Water quality, Water management (applied).

Data for leached cations,  (the sum of Ca(2+), Mg(2+), Na(+) and K(+)), and leached
Cl(-)  and  the ratio of cations to Cl(-)  leached from the root zone during a 4-year
experiment with bovine manures on a Hanford soil were presented.   Cation accumulation
in the soil and the cations leached were linearly correlated with cation input.
The removal of cations in harvested crops reached a maximum and then decreased as
the input of cations increased.  Leached Cl(-)  increased at a ratio of 1:1 with the
Cl(-)  input in excess of removal in harvested crops, whereas leached cations in-
creased with  increase in inputs in excess of removal in^crops and decreased with
decrease in the volume of leachate.   At low leachate volumes and with dry weights
of liquid and solid manures at 21 and 40 metric tons/ha per year,  respectively,
the cations leached were less than in the check plots.   At high leachate volumes
manures increased the cations leached relative to the check treatment at all rates
of manure.  The dominant factor in cation leaching was volume of leachate.  Care-
fully controlled irrigation to attain low leachate volumes combined with manure
applications at reasonable rates could be used to reduce the overall effect of
irrigation on the leaching of salts to groundwater.


                                      222

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 78:05G-043
 NITROGEN AND PHOSPHORUS LOSSES  IN RUNOFF FROM NO-TILL SOYBEANS,
 McDowell, L.L.,  Ryan, M.E., McGregor, K.C.,'and Greer, J.D.
 Sedimentation Laboratory, Oxford, Mississippi, United States Department of
 Agriculture.                       %
 Paper No. 78-2508, Presented at the 1978 Winter Meeting of the American Society
 of Agricultural  Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
 Illinois, 8 p.   10 fig, 4 tab,  18 ref.

 Descriptors:  Water pollution,  Water pollution control, Nitrogen, Phosphorus,
 Soil erosion, Runoff, Nutrients, Water quality control, Soybeans, Mississippi.

 No-till soybeans and corn can be grown on highly erodible loessial soils in
 north Mississippi with reduced  soil and plant nutrient losses.  Soil loss in
 1973 from no-till soybeans, planted directly through previous crop residues,
 was only 0.4 metric tons per hectare (t/ha) compared with 19 t/ha from conven-
 tional till.  Total (solution plus sediment) nitrogen (N) and phosphorus (P)
 losses from no-till soybeans were only 4.7 and 2.8 kg/ha, respectively, compared
 with 46.4 and 17.6 kg/ha from conventional till.  Where applicable, no-till is
 a best management practice for  reducing potential nonpoint pollution by sediments
 and plant nutrients in surface  runoff from agriculture.


 78:05G-044
 MINIMIZING SALT  IN DRAIN WATER  BY IRRIGATION MANAGEMENT—DESIGN AND INITIAL
 RESULTS OF ARIZONA FIELD STUDIES,
 Hoffman, G.J., Dirksen, C. , Ingvalson, R.D., Maas, E.V., and Oster, J.D.
 United States Salinity Laboratory, Agricultural Research Service, United States
 Department of Agriculture, 4500 Glenwood Drive, Riverside, California  92502.
 Agricultural Water Management,  Vol. 1, No. 3, p 233-252, November, 1978.  11 fig,
 3 tab, 19 ref.

 Descriptors:  Water management  (applied), Salinity, Drainage water, Water quality,
 Leaching, Return flow, Evapotranspiration, Oranges, Alfalfa, Arizona.

 Two field experiments were established in the We11ton-Mohawk Irrigation and Drainage
 District of southwestern Arizona to test the feasibility of decreasing the salt
 load in drainage water by reduced leaching.  Results were given for the initial
 2 years of the test for Valencia orange trees and the first year for alfalfa.  The
water application data, substantiated by salinity sensor readings and measures
 of soil chloride, indicated that the annual evapotranspiration of Valencia orange
was approximately 1375 mm on a  total area basis.  After 2 years, fruit yield and
 quality and tree growth were not significantly different from flood-irrigated
 trees that received 40% more water.  It was concluded that if these results per-
 sist, the salt load from citrus in the district could be reduced 40,000 Mg annually
by reduced leaching.   More importantly, because of the salinity of the groundwater
pumped for water table control, the salt load exported from the district could be
 reduced initially by 130,000 Mg annually.  Results indicated that the alfalfa
 experiment was underirrigated the first year and evapotranspiration was about
 1950 mm annually.  Comparisons  indicated that the level basin flood irrigated
check yielded 20% more than the experiment and had about 10% leaching, an effi-
ciency that can probably not be improved.


 78:050-045
 RESIDUAL NITRATE-N IN FINE SAND AS INFLUENCED BY N FERTILIZER AND WATER MANAGEMENT
PRACTICES,
Smika, D.E., and Watts, D.G.
United States Department of Agriculture, Science and Education Administration,
Akron, Colorado.
Soil Science Society of America Journal, Vol. 42, No.  6, p 923-926, November-
December, 1978.  5 fig, 1 tab,  6 ref.

Descriptors:  Nitrogen, Nitrates, Water management (applied), Nitrification,
Application methods,  Irrigation systems, Groundwater,  Water pollution, Return
flow, Corn (field).
                                      223

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This study showed that on fine sandy soils fertilizer N and water management
are the key to controlling NO3(-)N movement below the root zone of an irrigated
corn crop.  When the N was applied in one broadcast application at seeding, very
little N03(-)N remained in the soil at the end of the growing season, regardless
of the amount of growing season water application.,  Overwinter leaching of NO3(-)N
below the ISO-cm sampling depth was minimal with 13 cm of precipitation received
during these months.  When N was applied through the solid set sprinkler irrigation
system during the growing season before tasseling, water application rate and
total N applied determined the amount of N03(-)N that remained in the soil at the
end of the growing season.  During the overwinter period, NO3(-)N actually in-
creased in the soil due to nitrification of some of the NH4(+)-N.  With proper
N application and water management, the potential for NO3(-)N leaching below
the crops' root zone can be greatly reduced.


78:056-046
RELATIONSHIPS BETWEEN AGRICULTURAL LAND AND WATER QUALITY,
Coote, D.R., MacDonald, E.M., and DeHaan, R.
Land Resource Research Institute, Central Experimental Farm, Agriculture Canada,
Ottawa, Ontario.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 79-
92.  5 tab, 11 ref.

Descriptors:  Water quality, Water pollution. Land use, Agricultural watersheds,
Agricultural chemicals. Statistical methods. Great Lakes, Regression analysis.

The study described in this paper was developed as an adjunct to the Pilot
Watershed Studies of the International Reference Group on Great Lakes Pollution
from Land Use Activities (PLUARG) of the International Joint Commission (IJC)
with the objective of determining the relationships among water quality, pollu-
tant loadings and land use data gathered in watersheds representative of different
agricultural areas.  The approach taken was to:  (1)  identify and survey a number
of purely agricultural watersheds (nonagricultural land use essentially absent)
representative of different agricultural systems in the Canadian Great Lake Basin;
(2) monitor the water quality at the watershed outlet; and (3) examine statistical
relationships between the characteristics of these watersheds and the water quality
observed at their outlets.  A further objective of -the study was to provide a basis
for predictions of water quality in unmonitored agricultural areas of the Canadian
Great Lakes Basin.


78:05G-047
BEST MANAGEMENT PRACTICES FOR AGRICULTURE AND SILVICULTURE:  AN INTEGRATED
OVERVIEW,
Bailey, G.W., and Waddell, T.E.
United States Environmental Protection Agency, Environmental Research Laboratory,
Athens, Georgia.
Proceedings of the 1978 Cornell Agricultural Water Management Conference, p 33-56.
5 fig, 3 tab, 17 ref.

Descriptors:  Water management (applied), Management, Water pollution control,
Water pollution sources, Water quality, Legislation,  Social aspects, Economic
feasibility, Institutional constraints, Forest management.

The evolution of agricultural and silvicultural practices were examined to place
the environmental effectiveness of BMPs in perspective within today's control
efforts.  In addition, recent legislation was reviewed in terms of BMP identifica-
tion, selection, and implementation approaches.  The technical, social, and
economic aspects of BMPs were examined by means of a systems approach.  First,
the physical system characterized by natural and man-made inputs, system pro-
perties (e.g., topography and soil)  and outputs/pollutant load (i.e., sediment,
pesticides, plant nutrients, heavy metals, pathogens and easily oxidizable
organics) were discussed.  Second, this system was viewed as a partially con-
trollable system within the context of a larger socio-economic setting driven
by a multiplicity of exogenous forces.  Socio-economic aspects of BMPs were dis-
cussed in terms of economic efficiency, social acceptability, equity, implemen-
tation incentives, and institutional arrangements.  The paper identified and dis-
cussed a number of critical issues that demand attention.
                                     224

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 78:05G-048
 CONSERVATION  DISTRICT INVOLVEMENT  IN  208 NONPOINT SOURCE  IMPLEMENTATION,
 Williams, R.E.,  and  Lake, J.E.
 National Association of  Conservation  Districts, Washington, D.C.
 Proceedings of the 1978  Cornell Agricultural Waste Management Conference, p 57-
 67.

 Descriptors:   Water  pollution  control, Water quality act, Water law, Legislation,
 Water  management (applied). Erosion control, Sediment control, Water pollution
 sources, Water quality,  Soil conservation.

 A brief  history  of the establishment  of conservation districts was presented
 including their  authorities under  the state laws enabling conservation districts
 organization.  In addition, fifteen states have passed additional legislation
 providing districts  with the authority to participate in special erosion and
 sediment control programs.  Examples  of how these programs are working in several
 of the states  were discussed.  The relationships of these and other programs with
 the  new  thrust toward implementing nonpoint water quality plans using the Best
 Management Practice  approach was covered.  Three case studies were presented where
 districts have demonstrated their  abilities to be management agencies for imple-
 menting  Best Management  Practices.  Finally, conservation districts' involve-
 ment in  carrying out 208 nonpoint  implementation as a result of recent legislation
 (exj   Culver amendment)  was provided.  Administrative, technical, and funding
 roles  of state soil  conservation agencies and conservation districts in imple-
 menting  BMP's  were stressed.


 78:050-049
 THE  ROLE OF CONSERVATION PRACTICES AS BEST MANAGEMENT PRACTICES,
 Johnson, J.S.
 Soil Conservation Service, United  States Department of Agriculture, Washington,
 D.C.
 Proceedings of the 1978  Cornell Agricultural Waste Management Conference, p 69-
 78.  16  ref.

 Descriptors:   Water  pollution  control, Water pollution, Water quality control,
 Water  quality  act. Water quality,  Soil conservation. Management, Water pollution
 sources. Irrigation, Water conservation.

 The  combination  of conservation practices selected to meet the needs of a particu-
 lar  land and water problem and achieve the desired results was viewed as a resource
 management system.   Experience and research have shown that many resource manage-
 ment systems are highly  effective  in protecting and improving water quality.  The
 resource management  system selected may include agronomic, managerial, and struc-
 tural  practices  that reduce nonpoint source pollution and protect water quality.
 The best resource management system is one that keeps the water where it falls,
 protects the resource  base, and maintains water quality of the water that runs
 off.   it was suggested that such proved resource management systems can be used
 in achieving national  goals of improved water quality, and because of the recog-
 nized  effectiveness  of conservation practices and resource management sys.tem in
 controlling nonpoint source pollution, many of them can be selected and listed
 as BMP in Section 208  Water quality Management plans.


 78:050-050
 INTEGRATING WATER QUALITY AND  BEST MANAGEMENT PRACTICES,
 Taverni, A.P., and Dworsky, R.P.
 The New York State Assembly, Research Staff,  Albany, New York.
 Proceedings of the 1978  Cornell Agricultural Waste Management Conference, p 93-
 115.    4 fig, 6 tab,  15 ref.

 Descriptors:  Water quality control, Water quality,  Water pollution control,
Water quality act, Planning, Management, Water pollution, Hudson River,  Salinity.

 This paper discusses in detail the New York State Level B plans (section 209 of
 Public Law 92-500) which contribute to improved water quality through the use
 of common techniques.  Specifically, this paper focused on the Genesee River,
Hudson River and Lake Champlain.  It provided a summary of Best Management
 Practices and the relation of Best Management Practices to overall water quality
management.   Lastly,  this paper demonstrated the viability of a state integrated
planning approach.
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 78:05G-051
 ENVIRONMENTAL  IMPLICATIONS OF  TRENDS  IN AGRICULTURE AND  SILVICULTURE,
 Unger,  S.G.
 Development  Planning  and  Research Associates,  Incorporated, Manhattan, Kansas.
 Proceedings  of the  1978 Cornell Agricultural Waste Management Conference,
 p  117-131.   1  fig,  2  tab.

 Descriptors:   Environmental  sanitation, Pollutant identification, Water pollution
 sources, Water quality control, Agriculture, Pasture management, Range manage-
 ment, Forest management,  Environmental control, Pollution abatement.

 In a study sponsored  by the  Environmental Protection Agency  (EPA) the environmental
 implications of production-related  trends were assessed  in the  following five
 subsectors:  Agriculture—(1)  Nonirrigated crop production,  (2) Irrigated crop
 production,  (3) Livestock feedlot production,  (4)  Range and pasture management,
 and, Silviculture—(5)  Silviculture  and harvest management.  The period of
 analysis was 1976-2010, and  the emphasis was on the long-term future under
 moderate growth assumptions.   This  presentation summarized the  findings of the
 EPA study including the rating and  rankings—by a national evaluation workshop—
 of environmentally-related trends within each  of the five subsectors.  Also, a
 further analysis of the various types of trends within the crop production sub-
 sectors was made to determine  the relative importance of management practices—
 compared to  input-use restraints and  residual-output treatments—within the crop
 production system as  a potential means of environmental pollution control in the
 future.


 78:05G-052
 ESTIMATION AND MANAGEMENT OF THE CONTRIBUTION  BY MANURE FROM LIVESTOCK IN THE
 ONTARIO GREAT  LAKES BASIN TO THE PHOSPHORUS LOADING OF THE GREAT LAKES,
 Draper, D.W.,  Robinson, J.B.,  and Coote, D.R.
 Guelph  University, Guelph, Ontario, Canada, Department of Environmental Biology.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 159-
 174.  2 fig, 4  tab, 39 ref,  3  equ.
 (See 78:05A-016)


 78:05G-053
 THE FATE OF NITRATE IN SMALL STREAMS AND ITS MANAGEMENT IMPLICATIONS,
 Robinson, J.B., Whiteley, H.R., Stammers, W..,  Kaushik, N.K., and Sain, P.
 Guelph  University, Geulph, Ontario, Canada, Department of Environmental Biology.
 Proceedings of  the 1978 Cornell Agricultural Waste Management Conference, p 247-259.
 6  fig,  2 tab,  20 ref.
 (See 78:058-064)


 78:05G-054
 AN APPROACH TO WATER  RESOURCES EVALUATION OF NONPOINT SOURCES FROM SILVICULTURAL
 ACTIVITIES—A  PROCEDURAL HANDBOOK,
 Currier, J.B.,  Siverts, L.E.,  and Maloney, R.C.
 Watershed Systems Development  Group, United States Department of Agriculture—
 Forest  Service, Fort  Collins,  Colorado.
 Proceedings of  the 1978 Cornell Agricultural Waste Management Conference, p 271-280.
 1  fig,  1 ref.
 (See 78:05B-065)


 78:05G-055
 NONPOINT SOURCE POLLUTION FROM AGRICULTURE:  SOME SOCIOLOGICAL CONSIDERATIONS FOR
 IMPLEMENTING POLICY,
 van Es, J.C.,  and Keasler, L.C.
 Illinois University,  Urbana-Champaign, Department of Agricultural Economics.
 Proceedings of  the 1978 Cornell Agricultural Waste Management Conference, p 311-319.
 1  fig,  8 ref.

 Descriptors:  Water pollution  control, Social  aspects, Social participation,
Water pollution, Water quality, Water quality  control, Water policy, Water
 management (applied).
                                      226

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Most of the discussion on NFS pollution control deals with the economics and the
technical aspects of the issue.  In this paper the contributions sociological
analysis can make to the administration and' implementation of a NFS-pollution
control program were demonstrated.  The first theme developed in the paper
dealt with the distinction between policy goals and the objectives of specific
programs created to reach the policy goals.  The second theme dealt with the
issue of participation in programs.  The paper discussed the experience in
agriculture with voluntary and mandatory programs of change and the likely conse-
quences of choosing programs with voluntary or mandatory participation strategies.
It was concluded that the program administrators will be in a better position
to administer programs if they understand the relationship of the program ob-
jectives to the policy goal and make program implementation compatible with the
various programs objectives.


78:05G-056
ANIMAL MANURE MOVEMENT IN WINTER RUNOFF FOR DIFFERENT SURFACE CONDITIONS,
Thompson, D.B., Loudon, T.L., and Gerrish, J.B.
Minnesota University, St. Paul, Department of Agricultural Engineering.
Proceedings of the 1978 Cornell Agricultural Waste Management'Conference, p 145-
157.  1 fig, 4 tab, 16 ref.
(See 78:05A-018)


78:050-057
ESTIMATING PHOSPHORUS LOADING FROM LIVESTOCK WASTES:  SOME WISCONSIN RESULTS,
Moore, I.e., Madison, F.W., and Schneider, R.R.
Wisconsin University, Madison, Water Resources Center.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 175-
192.  3 fig, 7 tab, 17 ref.
(See 78:05A-019)


78:050-058
ECONOMIC IMPACTS OF POLICIES TO CONTROL EROSION AND SEDIMENTATION IN ILLINOIS
AND OTHER CORN-BELT STATES,
Seitz, W.D., Osteen, C., and Nelson, M.C.
Illinois University, Urbana, Institute for Environmental Studies.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 373-
382.  10 ref.

Descriptors:  Erosion control, Sediment control, Sedimentation, Soil erosion,
Economic impact, Agricultural watersheds, Linear programming, Water pollution
control, Water quality control, Corn belt.

This paper addressed 1) the costs to society of controlling agricultural nonpoint
sources of pollution, specifically erosion and sedimentation, and 2) the variation
in economic impacts as states or/and areas enact varying levels of control.  A
large linear programming model of the corn-belt region which accounts for
variable corn and soybean production and prices was used in the analysis.  This
model was used to evaluate alternative erosion control policies implemented in
selected areas of the corn belt.  At the corn belt level, impacts on social
cost, farm income, food costs, commodity prices and production, land use, and soil
loss were discussed.  The analysis of varying controls by areas was measured in
terms of impacts on the comparative advantage, farm income, crop production, land
use and soil loss of controls applied in Illinois and Wisconsin.  The paper also
reported the results of an analysis of the long-run impacts of soil erosion and
soil erosion control policies on farm income.  This analysis was conducted on a
representative watershed using a series of linear programming models with adjust-
ments to reflect the impacts of erosion on productivity.


78:05G-059
INSTITUTIONAL AND TECHNICAL ASPECTS OF THE DEVELOPMENT OF AGRICULTURAL BMPs IN
A GIVE-COUNTY RURAL/URBAN MICHIGAN REGION,
Jones, J.P., and Sutherland, J.C.
Williams & Works, Incorporated, Grand Rapids, Michigan.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 455-
462.  2 fig.


                                     227

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Descriptors:   Runoff, Soil erosion, Waste treatment, Water quality, Water
pollution, Management, Water pollution control, Water law, Michigan.

This  is a case history of the development of a truly management oriented Waste
Treatment Management Plan under the provisions of Section 208 of Public Law
92-500.  It emphasized the management organization at all levels—state, regional
and local—for the implementation of best management practices to control non-
point diffuse  sources of water pollution.  Major emphasis of the control and
management effort was directed toward urban and rural runoff and sedimentation;
agricultural pollution such as that from herbicides and pesticides; pollution
from construction practices and lesser nonpoint sources of water pollution such
as septic systems and sanitary landfills.


78:05G-060
DEVELOPMENT OF BMPs FOR AGRICULTURE—NEW YORK STATE STRATEGY,
Robillard, P.O., Walter, M.F., and Gilmour, R.
Cornell University, Ithaca, New York, Department of Agricultural Engineering.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 581-
595.  7 fig, 7 tab, 6 ref.

Descriptors:   Water quality control. Water pollution control, Water quality,
Water pollution, Water management (applied), Soil conservation, Farm management,
Planning, New  York, Sediment control.

The identification of specific problems, knowledge of the cause-effect relation-
ships, direct  installation costs and expected changes in farm income circumvent
the choice of  appropriate BMP's and their potential water quality benefits.  How
these concepts might be incorporated into a BMP development program for New York
State were reviewed.  Associated stages of BMP development and implementation
techniques were proposed.  Examples of this methodology were presented for two
case study dairy farms.  Candidate management practices were judged qualitatively
and quantitatively in reducing potential soil, plant nutrient and manurial
organic matter losses from cropland.  Estimated changes in farm income were cal-
culated for each measure.  The risk in adopting new farm management measures and
technology were considered in this BMP selection process.  The potential for
integrating soil erosion, agronomic recommendations and farm management concepts
into the water quality elements of conservation farm plans were found to be good.
Examples of this approach were presented.


78:05G-061
DEVELOPMENT OF A "208 PLAN" FOR AGRICULTURAL NONPOINT POLLUTION SOURCES IN ILLINOIS,
Vanderholm, D.H., Frank, J.F., and Taylor, A.G.
Illinois University, Urbana-Champaign, Department of Agricultural Engineering.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 563-580.

Descriptors:  Water pollution control, Water quality control, Water pollution,
Water quality, Planning, Pollution abatement, Water pollution sources, Soil conser-
vation, Illinois.

In June 1976",  a task force on Agricultural Non-Point Sources of Pollution was
appointed to advise the Illinois Environmental Protection Agency in producing a
comprehensive water pollution control plan.  Task force membership included
representatives from agriculture, state and federal agencies, universities, and
environmental groups.  The task force was divided into subcommittees to deal with
the specific areas of pesticide,  soil erosion, fertilizers,  livestock waste and
forestry and fruit production.  The problem assessment phase of the plan was com-
pleted in March of 1977 and the recommended Best Management Practices (BMPs) were
completed in October, 1977.  The last phase of the report deals with recommended
implementation methods and was completed in March 1978.  The objective of this
paper was to report the approach used by the task force for assessment of the
pollution problem from agricultural nonpoint sources, suggested BMPs, and imple-
mentation strategy as recommended by the task force for adoption in Illinois.


78:050-062
APPROACH FOR ANALYZING AND MANAGING AGRICULTURAL NONPOINT SOURCES IN THE STATE
OF MARYLAND,
Schoenhofer, R.F., Knight, W.A.,  and Hancock, C.V.

                                     228

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Water Resources Administration, State of Maryland Department of Natural
Resources, Annapolis, Maryland.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 551-
561.  2 fig, 9 ref.
                                \
Descriptors:  Water pollution control, Water quality control, Water quality, Water
quality act, Water pollution sources, Maryland, Management, Decision making,
Planning, Agricultural chemicals.

This paper covered the following topics:  (1) A description of the State of
Maryland, its 208 planning areas and agencies, and a brief history of nonpoint
source control efforts before the onset of 208 planning, which was prompted by
P.L. 92-500; (2) A description of the organizational structure of the agencies
involved in 208 planning as it related to agriculture; (3)  A description of the
philosophy and the benchmark decisions relating to the development of the agri-
cultural nonpoint source management program; and (4)  A description of an infor-
mation management system developed by the 208 program in cooperation with the
Soil Conservation Districts, and its application as a part of program development.


78:05G-063
ESTIMATION OF AGRICULTURAL NONPOINT LOADS TO THE WAKARUSA RIVER BASIN USING THE
"NONPOINT CALCULATOR",
Davis, M.J., and Nebgen, J.W.
Midwest Research Institute, Kansas City, Missouri.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 525-
550.  1 fig, 14 tab, 2 ref, 7 equ.

Descriptors:  Water pollution, Water quality, Water pollution control, Land
management, Programs, Agricultural watersheds, Sediment load, Pollutants,
Estimating, Kansas.

An analysis of the nonpoint pollution sources in the Wakarusa River basin in
eastern "Kansas was undertaken.  The Wakarusa basin is primarily rural, with the
principal nonpoint pollutant loads arising from agricultural land.  Soil
Conservation Service information for this basis was used to develop the "nonpoint-
calculator," a computerized methodology for estimating nonpoint loads.  This
procedure was developed under the sponsorship of the U.S. Environmental Protection
Agency.  The nonpoint calculator considers a variety of sources; pervious areas
(erosion-related pollutants), impervious areas (urban sources), feedlots, land-
fills, salinity from irrigation return flow, and acid mine drainage.  For the
Wakarusa River basin study, the nonpoint calculator was used only for previous
agricultural land.  The presentation described how the nonpoint calculator
operates, and the type of information needed for input,  it was shown that
analysis of the output from the nonpoint calculator can pinpoint areas which re-
quire the development of plans for load reduction, either to preserve water
quality or to maintain the soil resource.


78:05G-064
INTERACTIVE EFFECTS OF PESTICIDE PROPERTIES AND SELECTED CONSERVATION PRACTICES
ON RUNOFF LOSSES:  A SIMULATION STUDY,
Dean, J.D., and Mulkey, L.A.
Technology Development and Applications Branch, Environmental Research Laboratory,
United States Environmental Protection Agency, Athens, Georgia.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 715-
734.  7 fig, 3 tab, 28 ref.

Descriptors:  Agricultural runoff, Pesticide removal. Conservation, Simulation
analysis, Agricultural chemicals. Management, Sediment discharge, Water pollu-
tion, Water pollution control, Water quality.

The prohibitive cost of long-term collection of chemical runoff data from
agricultural activities makes the use of models attractive in evaluating impacts
of management practices.  This paper described a general methodology for model
implementation and cited a specific case to indicate the potential of simulation
studies for characterizing runoff losses.  To test the methodology, a study was
made using two different conservation practices on opposite ends of the managerial
spectrum, three different sorptive pesticide properties, ten gradually increasing
pesticide half-lives, and three meteorological input sequences for a total of 180

                                     229

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 simulation years.  The U.S. Environmental Protection Agency's Agricultural
 Runoff Management Model  (ARM) and data from the Southern Piedmont agricultural
 region were  used in  the  investigation.  Results showed the interactive effects
 of pesticidal properties, watershed hydrology, and conservation practices on
 runoff losses of the chemicals, in water and on sediment.


 78:05G-065
 MODELING SOIL AND WATER  CONSERVATION PRACTICES,
 Beyerlein, D.C., and Donigian, A.S.
 Hydrocomp, Incorporated, Palo Alto, California.
 Proceedings  of the 1978  Cornell Agricultural Waste Management Conference, p 687-
 713.  9 fig, 4 tab,  16 ref, 5 equ.

 Descriptors:  Agricultural runoff, Water conservation, Soil conservation, Water
 pollution, Model studies, Water quality, Agricultural watersheds, Sediment
 discharge, Frequency analysis, Watershed management.

 The U.S. Environmental Protection Agency's agricultural Runoff Management (ARM)
 Model was used to study  the effects of soil and water conservation practices
 (SWCP) on nonpoint pollution from agricultural lands.  The base conditions were
 defined as conventional  agricultural practices for the region.  Model parameters
 were then changed to represent the effects of a particular SWCP.  The three
 major SWCPs  studied  were terracing, contouring, and conservation tillage.  Con-
 tinuous simulations  of three to ten years in length were made to quantify the
 effects of each of the SWCPs compared to the base conditions.  Runoff, sediment
 loss, and pesticide  and  nutrient washoff in solution and on sediment for a SWCP
 were compared with the base condition results.  Results were analyzed both by
 total monthly and yearly amounts and by frequency of occurrence.  ARM Model
 results were displayed with a Calcomp plotter to give a visual representation
 of how and when runoff and pollutant amounts changed with different SWCPs.  The
 simulation methodology,  the selection and evaluation of model parameters for
 particular practices, and the evaluation of the results in terms of the effects
 of different SWCPs were  discussed.  Limitations of the model to represent certain
 agricultural practices were presented along with areas for future research.


 78:05G-066
 MATHEMATICAL MODELING OF WATER QUALITY EFFECTS OF AGRICULTURAL BEST MANAGEMENT
 PRACTICES,
 Tang, C.
 URS Company, Seattle, Washington.
 Proceedings of the 1978  Cornell Agricultural Waste Management Conference, p 625-
 647.  6 fig, 5 tab,  5 ref.

 Descriptors:  Water  quality control, Water pollution control, Water quality,
 Water pollution, Mathematical models, Agricultural runoff, Biochemical oxygen
 demand,  Ammonia, Coliforms, Washington.

 A series of computer models were used in the SNOMET/King County (Washington State)
 208 study to determine the water quality effects of the implementation of best
 management practices (BMPs) designed to reduce nonpoint pollutant runoff from
 agricultural activities.   Simulated results showed that under existing land use
 conditions, the pollutant reductions for BOD,  ammonia and fecal coliform loads
 in the study area after BMP application were about 70%, 85% and 75%, respectively.
 Under the simulation condition,  a combina'tion of 7 day - 10 year low flow regime
 and an annual summer storm, the results showed that the in-stream concentration
of  fecal coliforms after BMP application in the Upper Snohomish River, was
 greatly improved from a frequent violation to a satisfactory level with respect
 to the State Standards.  The results of these simulations helped to guide in the
 selection of BMPs for the agricultural areas.


 78:050-067
THE EVALUATION OF BEST MANAGEMENT PRACTICES FOR THE REDUCTION OF DIFFUSE POLLU-
TANTS IN AN AGRICULTURAL WATERSHED,
Cahill,  T.H., Pierson,  R.W.,  and Cohen, B.
 Resource Management Associates,  West Chester,  Pennsylvania.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p  465-
 490.  14 fig, 9 tab,  10 ref.

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Descriptors:  Agricultural watersheds, Land management/ Water pollution, Water
quality, Water quality control, Agricultural runoff, Eutrophication, Lake Erie,
Model studies, Great Lakes.

The Honey Creek watershed  (180 s*m.) in the Sandusky basin of north central Ohio
has been the subject of research by several agencies and institutions during
1976 and 1977.  The basin has served as a pilot study area for the development
of agricultural land management practices to reduce phosphorus input to Lake
Erie.  A computerized land resource data base has been created to evaluate options.
Current research centers on the calibration of the EPA Nonpoint Source Model
(NFS) for the watershed, with model parameter evaluation for BMP sensitivity.
Because of the size of the basin with respect to prior NPS model calibration
studies, 14 subbasin simulations were produced using the data base.  Routing
sub-routines were developed, using wave velocity for hydrographs and particle
velocity for chemographs.  Recommendations were made for model parameter inputs,
to reflect greater sensitivity for management analysis.


78:05G-068
A STATE PERSPECTIVE ON NONPOINT SOURCE MANAGEMENT,
Berle, P.A.A.
New York State Department of Environmental Conservation, Albany, New York.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 17-
24.

Descriptors:  Water pollution control, Water quality control, Water quality act,
Soil conservation, Water conservation, Water management (applied), State
governments, New York.

This paper projects the governmental perspective of the New York state on nonpoint
pollution control strategy.  The concept of Best Management Practice (BMP) for
nonpoint source control and management was endorsed.  To prevent water pollution
from rural nonpoint sources, it was felt necessary to develop BMP's tailored to
meet New York's unique physical, economic and agricultural conditions;  to identify
serious nonpoint water quality problems for special priority attention; and
participation by every landowner in the^existing cooperative soil and water con-
servation program.  It was concluded that since technically nonpoint pollution
control is a new and relatively unexplored area of concern, the initial BMP systems
must be carefully designed to stay within the limits of our current knowledge.


78:05G-069
BEST MANAGEMENT PRACTICES FOR SILVICULTURE,
Harper, W.C.
Weyerhaeuser Company, Tacoma, Washington.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 263-270.

Descriptors:  Forest management. Forest watersheds. Water quality control, Water
pollution control, Water quality, Management, Water quality act, Pollution abatement.

The silvicultural aspects related to Section 208 planning of Public Law 92-500 was
addressed to ensure that the resulting plan is compatible with long-term forest
management objectives.  It was suggested that alternative management practices are
developed for each site to allow land managers to select among an appropriate range
of acceptable management practices.  It was also suggested that an assessment of the
effectiveness of Best Management Practices in meeting land management goals, in-
cluding both water quality and timber production, must be conducted following im-
plementation of the 208 plan.


78:05G-070
BEST MANAGEMENT PRACTICES FOR FERTILIZER USE,
White, W.C., and Plate, H.
The Fertilizer Institute, Washington, D.C.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 133-141.
3 tab, 9 ref.

Descriptors:  Nutrient removal. Nutrient requirements, Fertilizers, Environmental
sanitation, Water pollution, Water quality. Management, Application methods, Timing,
Water quality control.

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A few examples were presented to illustrate the wide range of factors to consider
in controlling nutrient levels in soils as to maximize plant recovery and to
minimize loss to the environment.  Even with the best available matrix mathematics,
all individual factors cannot be quantitatively evaluated for every single eventual
possible field condition.  The judgement of the farmer must come into play in
exercising Best Management Practices (BMP's)  for nutrient use in crop production.
It was suggested that the following four BMP's for plant-nutrient use deserve
special attention:  (1)  matching rate of application closely to the need of each
soil-crop combination, (2)  time of fertilizer application, (3)   method of
application, and (4) forms of nutrients relative to crop recovery and loss to the
environment.


78:05G-071
BEST MANAGEMENT PRACTICES FOR AGRICULTURE AND SILVICULTURE,
Loehr, R.C., Haith, D.A., Walter, M.F., and Martin, C.S., Editors.
Cornell University, Ithaca, New York, College of Agriculture and Life Sciences.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, 154 fig,
159 tab, 490 ref, 57 equ.

Descriptors:  Conferences, Water quality, Water pollution, Water quality control,
Water pollution control, Water quality act, Federal water pollution control act,
Water management (applied), Conservation, Wastes.

The papers presented at the 1978 Cornell Agricultural Waste Management Conference
were grouped into the following catagories and published:  Governmental aspects;
Approaches for Best Management Practice (BMP)  selection; Nutrient management;
Silviculture; Economic, policy and institutional aspects; State and watershed
approaches; and Modeling Studies.  The emphasis for control of nonpoint pollution
sources was placed upon the use of BMP's rather than on the collection, treatment
and effluent standards approach used for control of point sources.


78:050-072
USER'S MANUAL FOR AGRICULTURAL RUNOFF MANAGEMENT  (ARM) MODEL,
Donigian, A.S., and Davis, H.H.
Hydrocomp Incorporated, Palo Alto, California  94304:
Publication No. EPA-600/3-78-080, August, 1978.   163 p,  16 fig, 25 tab, 33 ref,
3 append.

Descriptors:  Agricultural runoff, Model studies. Computer models, Computer
programs, Simulation analysis, Water pollution, Hydrologic budget, Sediment
load, Pesticide residues, Nutrient removal.

This user manual provides detailed instructions and guidelines for using the
Agricultural Runoff Management  (ARM) Model, Versions I and II.  The manual includes
a brief general description of the ARM Model structure,  operation, and components,
but the primary purpose of this document is to supply information, or sources of
information, to assist potential users in using,  calibrating, and applying the
ARM Model.  Data requirements and sources, model  input and output, and model
parameters has been described and discussed.  Extensive  guidelines are provided
for parameter evaluation and model calibration for runoff, sediment, pesticide,
and nutrient simulation.  Sample input sequences  and examples of model output
are included to clarify the tables describing model input and output.  The manual
also has discussed computer requirements and methods of  analysis of the continuous
information provided by the model.  This manual, when used with an understanding
of the simulated processes and the model algorithms, can provide a sound basis
for using  the ARM Model in the analysis of agricultural  nonpoint pollution pro-
blems and management practices.


78:05G-073
POLLUTION CONTROL MANUAL FOR IRRIGATED AGRICULTURE,
Kepler, K., Carlson, D., and Pitts, W.T.
Toups Corporation,  1966 West 15th Street, Loveland, Colorado  80537.
Publication No. EPA-908/3-78-002, August, 1978.   213 p,  30 fig, 28 tab, 131  ref,
4 append.
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Descriptors:  Water pollution, Water quality, Water pollution control, Agriculture,
Return flow, Salinity, Sediment, Nitrates, Pesticides, Water law, Salt balance.

The manual is intended to expand understanding of irrigated agriculture-water
quality relationships to a broad, group, including water quality interests, water
resource interests, and agricultural field technicians.  Information on collecting
pertinent information on the irrigation system, sampling techniques, and evaluation
techniques for determining the water quality impacts of return flows, combined
with beneficial use aspects allow irrigation to be put into perspective with other
elements of a water quality plan.  Development of best management practices (BMP's)
incorporate this water quality information plus information on the various agri-
cultural practices.  Understanding of local conditions affecting BMP's can be
developed within the evaluation framework.  Technical information on irrigated
agricultural practices and the pollutants associated with return flows is pre-
sented in a thoroughly-organized manner which makes it available to the layman
as well as to experienced personnel.  Traditional and recently developed irriga-
tion practices are developed and evaluated in terms of use, pollutant loading
pathways, cost, and effectiveness.  Pollutants are discussed in terms of occurence
in nature, loading mechanisms, evaluation techniques, and effect upon beneficial
use.


78:050-074
AN EVALUATION OF THE POTENTIAL FOR USING DRAINAGE CONTROL TO REDUCE NITRATE LOSS
FROM AGRICULTURAL FIELDS TO SURFACE WATERS,
Gilliam, J.W., Skaggs, R.W., and Weed, S.B.
North Carolina State University, Raleigh, Department of Soil Science, Agricultural
Experiment Station.
Water Resources Research Institute Report No. 128, PB 280 575, January, 1978.
108 p, 23 fig, 4 tab, 32 ref, 3 append.

Descriptors:  Nitrogen, Nitrates, Denitrification, Drainage water, Drainage
effects, Oxidation-reduction potential, Agriculture, Water pollution, Return
flow, Water pollution control.

The potential of drainage control to reduce the nitrate losses to surface waters
from artificially drained agricultural fields was investigated. . This research
was an outgrowth of previous work which showed that considerable denitrification
occurred in poorly drained soils with high water tables.  This resulted in less
nitrate leaving the fields in drainage waters than occurred in better drained
soils.  Two locations were selected for these experiments so as to cover a range
of soil conditions representative of large areas of drained soils in the Coastal
Plains of North Carolina.  Flashboard riser type water control structures were
installed in the four main tile lines or four collector ditches at each location.
Drainage was allowed to proceed normally or was prevented until water table in
the field reached any predetermined elevation.  The experimental observation
showed no significant change in nitrogen concentration of the drainage water
under controlled and uncontrolled conditions.  However, approximately 50%
reduction in drainage discharge was observed under controlled conditions resulting
in approximately 50% reduction in total nitrogen loss through drainage compared
to uncontrolled conditions.  It was concluded that it is potentially possible to
reduce the average winter loss of nitrate-nitrogen under controlled drainage
conditions.


78:05G-075
SALINITY MANAGEMENT OPTIONS FOR THE COLORADO RIVER,
Andersen, J.C., and Kleinman, A.P.
Utah State University, Logan, Utah Water Research Laboratory.
Water Resources Planning Series Report P-78-003, June, 1978.  344 p, 53 fig, 364
tab, 249 ref, 7 append.

Descriptors:  Colorado River, Colorado River Basin, Salinity, Water quality,
Water quality control, Water pollution, Economic impact, Linear programming,
Return flow, Model studies.

The study sought to provide additional information to estimate 1)  economic
damages caused by various salt concentrations to agricultural and municipal
water users and 2)  economic costs of salinity control measures by upstream
water users.  Damages were estimated for high salinity levels to provide

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 guidelines to project future  conditions.   Control  costs were  estimated with a
 physical model developed to predict the response of  soil, water, and crop
 factors.   Input-output models were  used to estimate  indirect  economic impacts.


 78:05G-076
 CROPPING AN ABANDONED FEEDLOT TO  PREVENT  DEEP PERCOLATION OF  NITRATE-NITROGEN,
 Schuman,  G.E.,  and  Elliott, L.F.
 United  States Department of Agriculture,  Agricultural Research Service, Route
 1,  Box  698,  Cheyenne,  Wyoming  82001.
 Soil  Science,  Vol.  126,  No. 4,  p  237-243,  October, 1978.  6 fig, 2 tab, 6 ref.

 Descriptors:   Nitrogen,  Nitrates, Feed lots, Water pollution, Water quality,
 Water quality control,  Groundwater,  Leachate, Crop production, Nebraska.

 An  abandoned feedlot was cropped  to  corn  (Zea mays L.) and alfalfa (Medicago
 sativa  L.)  to prevent  excess  buildup and  deep percolation of  NO3-N from the
 organic and  NH4-N accumulations from the  feedlot operation.   To eliminate part
 of  the  N  and salt accumulation, 15  cm of  surface material was removed from half
 the plots and replaced with field soil.   Alfalfa production was 14.1 and 11.8
 metric  tons/ha, and corn forage production was 8.0 and 6.7 metric tons/ha,
 from  the  intact surface  and removed  surface treatments, respectively.  Nitrogen
 uptake  was two and  one-half to  three times greater for alfalfa than for corn,
 which was reflected by the NO3-N  content  of the respective soil profiles.
 Nitrate-N content of the corn forage exceeded 2000 ppm (above the acceptable
 limit for livestock consumption), whereas  the alfalfa averaged only 857 ppm,
 which would  allow using  it as a feed without ensiling.  Nitrate buildup in
 the soil  profiles was  greater when the surface material remained in place; the
 results indicated that with proper cropping, however, either method would prevent
 excess  NO3-N  accumulation.


 78:05G-077
 GROUNDWATER CONTAMINATION BY FERTILIZER NITROGEN,
 Duke, H.R., Smika,  D.E.,  and Heermann, D.F.
 United  States  Department  of Agriculture, Fort Collins, Colorado  80521.
 Journal of the Irrigation and Drainage Division, American Society of Civil
 Engineers, Vol. 104, No.  IR3,  p 283-291, September, 1978.   6 fig, 2 tab, 8 ref.

 Descriptors:  Water pollution, Water pollution control, Nitrogen, Fertilizers,
 Nitrates,  Denitrification, Groundwater, Water quality, Return flow, Water
 management  (applied),  Leachate.

 It was  shown that excessive irrigation of the sandy soils  to which center pivot
 sprinklers are adaptable can result  in leaching of significant amounts of nitrogen
 fertilizer as N03(-).   Careful water management is an effective means of controlling
 N03-N losses.  The USDA  irrigation scheduling program was  used successfully to
 determine  the timing and amount of irrigation necessary to maintain high crop
 yields yet minimize leaching losses.  Although significant NO3-N losses  were
measured  from fields in the study area, neither the fraction of that NO3(-)  pre-
 sent  in return flows nor the mechanism of possible denitrification had been
 identified.  It was expected that if, in fact, significant denitrification occurred
 in  the vicinity of the water table as the data suggested,  the potential  for
groundwater pollution by leached nitrates is considerably  reduced.   Even so,  care-
 ful water management was considered to be an important factor in the irrigation
program as it affects  efficiency of fertilizer utilization,  cost of energy for
pumping, and ultimately the yield of crops produced.
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                                   SECTION XXV


                           WATER RESOURCES AND PLANNING

                        TECHNIQUES OF PLANNING (GROUP 06A)


 78:06A-001
 IDENTIFICATION AND INITIAL EVALUATION OF IRRIGATION RETURN FLOW MODELS,
 Walker, W.R.
 Irrigation Hydrology Company,  P.O.  Box 1544, Fort Collins, Colorado  80522.
 Publication No. EPA-600/2-78-144,  July,  1978.  124 p,  3 fig, 4 tab, 160 ref,  6
 append.

 Descriptors:  Mathematical models,  Irrigation,  Water resources,  Water pollution,
 Water,  Simulation, Prediction,  Water quality, Soil water, Soil chemistry.

 A broad based literature review was undertaken  to identify studies that had
 yielded digital computer models applicable to irrigation return flow (IRF)
 systems.  The programs not listed  in technical  reports or papers were requested
 from the various authors.  The  results of this  work are 43 computer models
 applicable all or in part to the analysis of IRF's and their quality.   A brief
 evaluation of each model is given.   IRF  modeling technology is well developed
 theoretically but not completely verified due to the large scale of the irriga-
 tion system.  Most models remain in the  research sphere and need to be redefined
 for the wider utilization of planners.   Field data are generally not available
 to satisfy the input requirements of most IRF models.   Accuracies of predictions
 need to be determined against standardized conditions  in order to further model
 development and parameter sensitivities  should  be investigated to isolate the
 most important field data.


 78:06A-002
 MATHEMATICAL MODELING OF PESTICIDES IN THE ENVIRONMENT,
 Hill, J.  IV
 Environmental Research Laboratory,  United States Environmental Protection Agency,
 College Station Road,  Athens, Georgia 30601.
 In:  Symposium on  Environmental  Transport and Transformation of  Pesticides, Octo-
 ber, 1976,  Tbilis,  USSR.  EPA-600/9-78-003,  February,  1978,  Athens,  Georgia,  p
 194-197.   24  ref.

 Descriptors:   Pesticides, Pesticide toxicity, Mathematical models,  Environmental
 effects,  Ecosystems,  Model  studies.

 This paper recommends  that  research needs to be  directed toward  mathematical
 modeling  that allows  translation of laboratory measurements of pesticide effects
 on  growth,  physiology,  and  environmental  interaction to  field conditions.  Fur-
 ther, it  suggests  that models need  to be  developed that  estimate whole  system
 behavior  based upon data representing a limited  set of  component interactions.
 Hierarchial models with constrained subsystems and homomorphic structures derived
 from influence analysis may accomplish these goals in  the near future.


 78:06A-003
 PREDICTING  AND SIMULATING PESTICIDE TRANSPORT FROM AGRICULTURAL  LAND:   MATHEMAT-
 ICAL MODEL  DEVELOPMENT AND  TESTING,
 Bailey, G.W.  and Nicholson,  H.P.
 Environmental  Research Laboratory,  United States Environmental Protection Agency,
 College Station Road,  Athens, Georgia 30601.
In:  Symposium on Environmental Transport and Transformation of Pesticides,  Octo-
ber, 1976, Tbilis, USSR.  EPA-600/9-78-003, February, 1978, Athens, Georgia,  p 30-
37.  26  ref.
                                      235

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 Descriptors:   Pesticides, Pesticide toxicity, Pollutants, Pollution abatement,
 Environmental  effects, Computer models, Mathematical models, Simulation analysis.
 Small watersheds, Basins.

 The  transport  of pesticides  from agricultural lands and other compartments of the
 environment has generated public apprehension concerning the fate and effects of
 these compounds.  Legislative mandates require guidelines to be developed cover-
 ing  pesticide  use in order to prevent or minimize water pollution resulting from
 pesticide  transport from agricultural land.  Computer simulation models of the
 dynamic multiple rainfall-event type are being developed and refined to describe
 and  predict quantitatively transport of pesticides from soil as a function of
 agricultural management practices, watershed characteristics, climatic factors,
 and  properties of soils and  pesticides.  This paper discusses the steps involved
 in development, testing and  verification of such models.


 78:06A-004
 TRANSIENT  SUBSURFACE DRAINAGE ON SLOPING IRRIGATED LAND,
 Yeh, H.J., and King, L.G.
 Washington State University, Pullman, Department of Agricultural Engineering.
 Paper No.  78-2037, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 21 p.  7 fig, 15 ref,
 2 equ.

 Descriptors:   Subsurface drainage, Subsurface drains, Irrigated land, Canal
 seepage, Slopes, Interception, Numerical analysis. Water table, Irrigation,
 Hydrodynamics.

 Parallel subsurface drains on sloping land were studied.  Source of water was
 upslope seepage such as from a canal as well as intermittant irrigation over the
 drains.  The ground surface  was treated as a boundary so that both fully and
 partially  saturated flow conditions existed within the soil region under study.
 The water  table location was determined from the numerical solution of hydraulic
 head as a  function of space  coordinates.  ADI methods were used to solve the basic
 partial differential equation together with appropriate initial and boundary
 values.  Land  slopes of up to 15 degrees from the horizontal were studied.  Water
 table fluctuation and drain  discharge were obtained over several irrigation cycles.
 During recession of the water table following an irrigation, the location of the
 maximum water  table height between the drains moved toward the lower drain.  The
water table recession following an irrigation was compared with existing theories
 using only saturated flow for parallel drains on flat land.  The results of this
 study showed the water table height as a function of time to be greater than pre-
 dicted by existing theories  even for quite small slopes.  The effects of partially
 saturated flow and land slope on this result are discussed.


 78:06A-005
 INTERCEPTOR DRAINS ON SLOPING LAND,
 Gharaaty-Sani, R.,  and King, L.G.
Washington State University, Pullman, Department of Agricultural Engineering.
 Paper No. 78-2038,  Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 21 p.  11 fig, 2 tab,
 21 ref.

 Descriptors:  Subsurface drains,  Subsurface drainage,  Interception, Canal seepage,
 Seepage control, Steady flow. Numerical analysis. Seepage, Flow rates,  Water
 table.

A single subsurface drain intercepting seepage from an upslope source such as a
 canal was studied under steady flow conditions.   Numerical methods were used to
 solve the nonlinear partial differential equation describing the two-dimensional
problem with both partially and fully saturated flow occurring.  Three different
soils and three different depths  of water in the canal were studied using this
model.  The resulting water table  and drain discharge were compared with pub-
 lished theory based upon laboratory flume studies which neglected or minimized
partially saturated flow.   The published theory predicts water table shape arid
 location adequately for design purposes; however, the drain discharge given by
 such theory is low (sometimes for  fine textured soils,  as low as fifty percent of
                                      236

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that given by this study).  Neglecting partially saturated flow could lead to
undersized drains on sloping lands.


78:06A-006
DRAINAGE REQUIREMENTS FOR LOWLAND RICE,
Undan, R.C., Phillips, A.L., and Hill, R.W.
Utah State University, Logan, Department of Agriculture and Irrigation
Engineering.
Paper No. 78-2041, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 21 p.   10 fig, 5 tab,
2 ref.

Descriptors:  Drainage, Rice, Drainage effects, Submerged plants, Submergence,
Rainfall, Simulation analysis, Computer models, Submerged vegetation stage,
Construction costs.

Field experiments were conducted in the Philippines with the IR-30 variety to
determine the effects of depth and duration of submergence on rice yields, and
the data used with rainfall and other physical information as bases for develop-
ing guidelines for drainage system capacity selection.


78:06A-007
CENTER PIVOT IRRIGATION IN THE COLUMBIA BASIN OF WASHINGTON AND OREGON:  DYNAMICS
AND IMPLICATIONS,
Muckleston, K.W., and Highsmith, R.M.
Oregon State University, Corvallis, Department of Geography.
Water Resources Bulletin, Vol. 14, No. 5, p 1121-1128, October, 1978.  1 fig, 13
ref.

Descriptors:  Irrigation, Sprinkler irrigation, Columbia River, Hydroelectric
power, Institutions, Water law, Oregon, Washington, Social impact, Economic
impact.

Impacts of center pivot irrigation in the Columbia Basin were reviewed.  As of
1976, over 225,000 acres were being irrigated by center pivot units in a five-
county area of the basin in Oregon and Washington.  Most of the development took
place since 1970.  Dynamic application of center pivot technology altered the
concept of irrigability in the study area, converting lands that were often roll-
ing, sandy, and plagued by wind erosion from low grade grazing to productive
irrigated units.  This development was entirely by private enterprise, with large
corporate farms accounting for much of the effort.  Little prior comprehensive
planning or coordination took place.  When the circulation of water is altered on
such a massive scale, however, unplanned impacts may be far reaching.  In this
case they include:  1)  acceleration of the shift to high cost thermoelectric
generation, 2) alteration of state institutions designed to allocate water, and
3) possible significant alterations of the socioeconomic fabric of small rural
service centers.


78:06A-008
OPTIMAL OPERATION OF LARGE AGRICULTURAL WATERSHEDS WITH WATER QUALITY CONSTRAINTS,
Williams, J.R., and Hann, R.W., Jr.
Texas ASM University, College Station,  Department of Civil Engineering.
Publication No. 96, April, 1978.  151 p,  7 fig, 16 tab, 50 ref, 127 equ.

Descriptors:  Agricultural watersheds, Sediment yield, Phosphorus, Nitrogen,
Runoff, Forecasting, Model studies, Routing, Water quality,  Linear programming.
Optimization.

Models were developed for predicting daily sediment, phosphorus,  and nitrogen
yields from small watersheds; routing the yields through large watersheds;  and
determining the optimal operating policy of the large watershed.   The model for
predicting daily sediment, phosphorus, and nitrogen was developed by refining
existing models and building new ones when existing models were considered
inadequate.
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78:06A-009
NUMERICAL MODEL FOR SATURATED-UNSATURATED FLOW IN DEFORMABLE POROUS MEDIA 3.
APPLICATIONS,
Narasimhan, T.N., and Witherspoon, P.A.
California University, Berkeley, Earth Sciences Division.
Water Resources Research, Vol. 14, No. 6, p 1017-1034, December, 1978.  46 fig,
1 tab, 26 ref, 14 equ.

Descriptors:  Saturated flow, Unsaturated flow, Porous media, Deformation,
Numerical analysis, Model studies, Computer models, Land subsidence, Soil water
movement, Subsurface flow.

This is the third and conclusive part of a three-paper series and describes the
application of a numerical model for saturated-unsaturated flow in deformable
porous media.  In all, ten illustrative examples were presented not only to
demonstrate the validity of the method but also to highlight the fundamental
unity that exists in the basic principles of the fields of hydrogeology, soil
mechanics, and soil physics.  The chosen examples involved such diverse phenomena
as soil consolidation, infiltration, and drainage and generation of fluid pres-
sures due to cyclic loading such as earthquakes.


78:06A-010
ON THE CHOICE OF THE "APPROPRIATE MODEL" FOR WATER RESOURCES PLANNING AND MANAGE-
MENT,
Rogers, P.
Harvard University, Cambridge, Massachusetts, Department of City and Regional
Planning.
Water Resources Research, Vol. 14, No. 6, p 1003-1010, December, 1978.  4 fig,
6 tab, 14 ref, 36 equ.

Descriptors:  Water resources, Water resources development, Planning, Management,
Model studies, Computer models, Computer programs, Mathematical models, Opera-
tions research. Analytical techniques.

The use of symbolic models has become widespread in water resources planning and
management.  The operations research literature, however, gives little guide as
to the choice of the most appropriate model for any situation.  This paper out-
lined a method for comparing models of differing complexity applied to a given
situation.  The hypothesis that simpler models are more appropriate than more
representative but more complex models were tested on two simple irrigation
examples.


 78:06A-011
 THREE-DIMENSIONAL MODELING  OF GROUNDWATER FLOW  SYSTEMS,
 Frind,  E.O.,  and Verge, M.J.
Waterloo  University, Waterloo, Ontario,  Canada  N2L  3G1,  Department of Earth
 Sciences.
Water Resources Research, Vol. 14,  No.  5, p  844-856,  October,  1978.   15  fig,
 3  tab,  30  refr 15  equ,  1  append.
 (See 78:043-011)


 78:06A-012
 CLIMATE,  SOIL AND  VEGETATION 7.   A DERIVED DISTRIBUTION  OF ANNUAL WATER YIELD,
 Eagleson,  P.S.                                                            .
 Massachusetts Institute of  Technology,  Cambridge,  Department of Civil Engineering.
 Water Resources  Research, Vol.  14,  No.  5, p  765-776,  October,  1978.   10  fig,
 3  tab,  13 ref,  35  equ.
 (See 78:02A-007)


 78:06A-013
 SOME PROPOSITIONS  ABOUT IRRIGATION PROJECT AND SYSTEM MANAGEMENT,
 Bottrall,  A.F.                                                           .  .
 Overseas Development Institute,  London,  United Kingdom,  Agricultural Administra-
 tion Unit.
 ICID Bulletin,  Vol.  27,  No.  2, p 68-72,  July,  1978.   1 tab.
                                     238

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 Descriptors:  Water management  (applied), Irrigation, Irrigation programs.
 Agriculture,  Decision making. Management, Project planning, Irrigation design,
 Irrigation operation and maintenance, Crop production.

 This  is a modified version of a gaper presented at the Overseas Development
 Institute Workshop on Choices in Irrigation Management, held from 27 September-
 1 October, 1976 at the University of Kent, Canterbury, (U.K.).  The object
 of this paper is  to put forward some generalized propositions about certain
 aspects of irrigation management in developing countries on which, whatever the
 characteristics of a particular project or system may be, strategic decisions
 will  at some  point have to be mdde.  The propositions are concerned primarily
 with  projects dependent on surface water delivery systems.  The propositions
 advanced in this  paper are derived primarily from observations made during field
 research in North West India and from the desk review of case studies in other
 parts of the  developing world.  The first set of propositions is concerned
 with  the broader  aspects of project organization and management, the second
 set with more detailed aspects of water delivery system design and operations.
 But there is  clearly a large degree of interdependence between propositions in
 each  set.


 78:06A-014
 ESTIMATING IMPACTS OF SILVICULTURAL MANAGEMENT PRACTICES ON FOREST ECOSYSTEMS,
 Larson, P.R., Ffolliott, P.P., Rasmussen, W.O., and Carder, D.R.
 Rocky Mountain Forest and Range Experiment Station, United States Department
 of Agriculture—Forest Service, Flagstaff, Arizona.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference,
 p 281-294.  19 ref.

 Descriptors:  Forest management, Forestry, Ecosystems, Computer models, Simula-
 tion analysis, Land use, Planning, Water quality, Streamflow.

 A family of computer simulation modules was described that would aid forest
 managers and  land use planners estimate the impact of management activities on
 the natural resources of the forest ecosystem.   This family, called ECOSIM,
 includes three general modules:  FLORA for estimating responses of the forest
 overstory, herbaceous understory, and organic matter; FAUNA for evaluating
 animal habitats,  carrying capacity, and population dynamics; and WATER for
 assessing streamflow yield, sedimentation, and chemical quality.  A command
 system enables users to operate all modules through a common language written
 in straight forward user terminology.  The design gives flexibility in repre-
 senting management activities by operating selected modules interactively on
 an appropriate data base.


 78-.06A-015
 SIMULATION OF STORMWATER RUNOFF AND SEDIMENT YIELD FOR ASSESSING THE IMPACT
 OF SILVICULTURE PRACTICES,
 Li,  R.M., Eggert,  K.G., and Simons, D.B.
 Colorado State University, Fort Collins,  Department of Civil Engineering.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference,
 p. 295-307.  6 fig, 11 ref, 11 equ.

 Descriptors:  Watershed management. Water yield.  Sediment yield, Forest
management, Model studies, Simulation analysis, Storm runoff.

 During the past two decades several watershed modeling techniques have been
 developed to  allow the prediction of water and sediment yield.   The estimation
of infiltration,  runoff and sediment yield are the major process components
 required for  simulating watershed response.   These process models,  when based
 on sound physical reasoning are generally recognized as an important predictive
 tool in assessing the impact of land use  and silviculture management schemes
 on the environment.  Unfortunately, these models  are often necessarily complex
 in formulation and require considerable expertise and computer time to achieve
 reasonable results.  Therefore,  although  quite accurate,  their complexity
often seems to inhibit their utility.  In order to generate an answer quickly
and with reasonable expenditure, easier techniques such as the basin recharge
method,  the unit hydrograph and the Universal Soil Loss Equation are often
used despite  their deficiencies.  The simple watershed model presented in this
paper combines the advantages of a nonlinear,  physically based approach with
 the utility of an interactive format.
                                    239

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78:06A-016
METHODOLOGY FOR DETERMINING THE OPTIMAL MIX OF BMPs AND AGRICULTURAL PRODUCTION
MODIFICATIONS,
Heaney, J.P., and Ammon, D.C.
Florida University, Gainesville, Department of Environmental Engineering Sciences.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p
649-664.  17 fig, 1 tab, 11 ref, 3 equ.

Descriptors:  Wastes, Pollution abatement, Pollutants, Detention reservoirs,
Sediment control, Linear programming, Model studies, Sediment discharge, Dairy
industry. Water pollution.

A simple procedure for determining the optimal mix of upstream and downstream
controls in an urban area was presented by Heaney and Nix (EPA-600/2-77-083,
1977).  This procedure was extended to permit evaluation of agricultural areas.
The main different between urban  and agricultural problems is that the farmer
may consider production modifications in response to an imposed restriction on
pollutant discharge.  A linear programming model was developed earlier by other
research workers which allows one to determine the production adjustments that
could be made on a dairy farm facing nutrient limitations.  This model was
coupled with information on Best Management Practices' effectiveness presented
in another publication and was extended to evaluate waste management problems.


78:06A-017
USER'S MANUAL FOR AGRICULTURAL RUNOFF MANAGEMENT (ARM)  MODEL,
Donigian, A.S., and Davis, H.H.
Hydrocomp Incorporated, Palo Alto, California  94304.
Publication No. EPA-600/3-78-080, August, 1978.  163 p, 16 fig, 25 tab, 33 ref,
3 append.
(See 78:05G-072)
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                                     SECTION XXVI


                              WATER RESOURCES PLANNING

                            EVALUATION PROCESS (GROUP 06B)


 78:068-001
 AN ECONOMIC METHODOLOGY FOR EVALUATING "BEST MANAGEMENT PRACTICES" IN THE SAN
 JOAQUIN VALLEY OF CALIFORNIA,
 Horner, G.L., Dudek, D.J., and McKusick, R.B.
 Economics, Statistics, and Cooperatives Service, United States Department of
 Agriculture.
 Proceedings of National Conference on Management of Nitrogen in Irrigated
 Agriculture, California University, Sacramento,  California, p 369-393, May 15-18,
 1978.  1 fig, 1 tab, 20 ref.

 Descriptors:  Return flow, Economic prediction,  Water quality, Management,
 Environmental effects.

 Section 208 of Public Law 92-500 (The Federal Water Pollution Control Act
 Amendments of 1972)  requires the preparation of  areawide waste treatment management
 plans.  Agricultural related pollutants such as  subsurface drainage water and
 irrigation tailwater containing nutrients,  sediment and pesticides must be
 identified and procedures and methods to control such discharges specified.
 Under Section 208, the reduction of pollutants may be achieved by adopting a
 set of "best management practices" that could include varying economic incentives,
 establishing resource use controls and suggesting public resource investment.
 To determine the economic and environmental impact of "best management practices,"
 a methodology must be derived that specifies the relationship of agricultural
 production practices to water and land quality and the economic cost and benefit
 of changing those practices.  Such a methodology is being developed to systemati-
 cally collect and organize physical and economic data, specify the physical
 and economic relationships and estimate the changes in agricultural production,
 income, employment and resource demands from proposed "best management practices."


 78:06B-002
 EVALUATION OF MEASURES FOR CONTROLLING SEDIMENT  AND NUTRIENT LOSSES FROM IRRIGATED
 AREAS,
 Fitzsimmons, D.W., Brockway, C.E., Busch, J.R.,  Conklin,  L.R., and Long,  R.B.
 Idaho University,  Moscow, Idaho Agricultural Experiment Station.
 Publication No.  EPA-600/2-78-138, July, 1978.  150 p, 51 fig, 82  tab, 59  ref.

 Descriptors:  Irrigation, Soil conservation, Water quality, Salinity, Economic
 analysis,  Management.

 Field studies were conducted in two southern Idaho areas to determine the effects
 of different management practices on the quality and quantity of  the runoff from
 surface-irrigated fields.  Pollutant removal systems (primarily mini-basins,
 vegetated  buffer strips and sediment retention ponds)  were installed at some  of
 the study  sites  and evaluated to determine  their effectiveness in removing sediment
 and other  materials from return flows.  The results indicate that water,  sediment
 and nutrient losses from surface-irrigated  areas can be greatly reduced or elimi-
 nated by the use of certain types of management  practices  and/or  pollutant removal
 systems.   Linear programming models were used to determine the economic impacts  of
'using different  types of practices to control surface runoff and  sediment losses
 from model farms.   The results indicate that sediment losses from surface-irrigated
 fields can be reduced by as much as 50 percent at modest cost. Elimination of
 surface runoff and sediment losses would require the use of sprinkler irrigation
 systems and would  decrease net income by about 15%.   Some  of the  overall  impacts
 of pollutant losses from surface-irrigated  areas were evaluated.   The annual
 cost of removing sediment from canals and ditches in the Boise Valley was found
 to be about $20  per hectare.  Irrigation return  flows contribute  to water quality
 problems in the  Boise River and downstream  in the Snake River.
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 78:068-003
 TOPOLOGICAL  CLASSIFICATIONS  OF  DRAINAGE NETWORKS:  AN EVALUATION,
 Onesti,  L.J.,  and  Miller, T.K.
 Indiana  University, Bloomington,  Department of Geography.
 Water  Resources  Research, Vol.  14, No. 1, p 144-148, February, 1978.  3 fig, 2 tab,
 17  ref.

 Descriptors:   Drainage, Channels, Geomorphology, Networks, Classification, Basins,
 Correlation  analysis.

 Channel  networks for  103 drainage basins ranging in size from 0.65 to 199 sq km
 were classified  according to 9  topologic systems ranging from Strahler's order
 and Shreve's magnitude to those recently derived by Werner and Smart.  Correlation
 coefficients and coefficients of  determination were calculated to test the
 relationship between  these systems and {10} characteristics of drainage basins
 and stream channels.  The results suggest that (1) network properties are closely
 associated with basin area and  with other characteristics primarily determined by
 area,  (2) the  hydraulic variables are essentially unrelated to all topologic
 systems  analyzed,  and (3) certain newly proposed topologic systems* are unrelated
 to  all characteristics tested,  including area.


 78:06B-004
 IMPACT OF ENERGY DEVELOPMENT ON GROUNDWATER,
 The Task Committee on the Impact of Energy Development on Groundwater Resources
 of  the Groundwater Hydrology Committee of the Hydraulics Division,
 American Society of Civil Engineers, New York, New York.
 Journal  of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
 No. HY2, p 157-168, February, 1978.  3 fig, 4 tab, 4 ref, 1 append.

 Descriptors:   Groundwater resources, Energy, Hydrology, Hydrologic aspects, Oil,
 Gases, Coals,  Oil  shales, Nuclear energy.

 Available information indicates that energy development in the U.S. will not soon
 deplete  or degrade groundwater  resources over widespread areas,  Very acute effects
 may occur locally  in the next few years, and many isolated, but serious, problems
 exist now.  Impacts beyond about 1990 are difficult to anticipate because of uncer-
 tainties about developable energy resources, development economics and policies,
 and technological  advancement.  However, it seems likely that predicted energy
 development will cause further  competition for both surface- and groundwater
 resources and  that the consequent greater waste outputs will add to pollution
 impacts.  These adverse impacts can be avoided or reduced by timely and compre-
 hensive planning which also should serve to enhance potential beneficial impacts.


 78:06B-005
 DESCRIBING IRRIGATION EFFICIENCY AND UNIFORMITY,
 On-Farm Irrigation Committee of the Irrigation and Drainage Division,
 American Society of Civil Engineers.
 Journal of the Irrigation and Drainage Division,  American Society of Civil
 Engineers, Vol. 104, No. IR1, p 35-41, March, 1978.  3 fig, 11 ref, 6 equ, 1 append.

 Descriptors:   Irrigation efficiency, Uniformity coefficient, Standards,  Irrigation,
 Soil moisture, Efficiencies,  Distribution.

 There is an urgent need for standardization of efficiency terms used in on-farm
 irrigation.   The purpose of this paper is to provide meanings for several such
 terms to reduce the vagueness and resulting confusion that now exists.  The
 committee hopes these definitions will be accepted as standards,  thus reducing
 conflicting usage and the consequent need for redefinition each time such terms
 are used.  Only terms applicable to on-farm irrigation practices  are presented,
 although many may be usable for larger units such as irrigation districts or basin
wide projects.


 78:066-006
 COMPUTER PROGRAMMING SOLID SET SYSTEMS,
 Griffin, S.G.
The Toro Company, Riverside,  California.


                                      242

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 Paper No. 79-2012, Presented at the 1978 Summer Meeting of  the American Society
 of Agricultural Engineers,  June 27-30,  1978,  Logan,  Utah,  9 p.
 (See 78:03F-058)


 78:068-007
 ECONOMICS OF IRRIGATION,
 Sheffield, L.F.
 Nebraska University,  Lincoln,  Department of Agricultural Economics.
 Proceedings of The Irrigation  Association, Stouffer's  Towers,  Cincinnati,  Ohio,
 p  76-90, February 26-28,  1978.   5  fig,  7 tab.

 Descriptors:  Sprinkler irrigation.  Economic  prediction, Economic  impact,  Irrigation,
 Irrigated land,  Cost  analysis,  Agriculture, Corn belt,  Great Plains.

 This paper reviews and discusses the accelerated growth of  irrigated  agriculture
 with center pivot irrigation systems in the Great Plains Region in the  1970's,
 and the reasons  behind the  severity  and widespread effects  of  the  current  cost-
 price squeeze on farmers  and agri-business community.   A detailed  analysis of the
 economics of irrigation leads  to the conclusion that irrigated  agriculture and  the
 irrigation industry in the  United  States faces  a bright future  despite  its present
 temporary problems.


 78:068-008
 PREDICTING YIELDS,
 Haun,  J.R.
 Clemson University, South Carolina,  Department  of Horticulture.
 Crops  and Soils Magazine, Vol.  31, No.  2, p 7-9,  November,  1978.   3 fig.
 (See 78:021-035)


 78:068-009
 DETERMINATION OF  OPTIMAL WELL CAPACITIES FOR CONTINUOUS IRRIGATION PROGRAMS,
 Sanghi,  A.K.,  Johnson,  D.,  and  Kuepper,  G.
 Washington University,  St.  Louis, Missouri, Center for  the Biology of Natural
 Systems.
 CBNS-AE-9,  NSF/RA-78-0017,  January,  1978.  50 p,  11  fig, 17  tab, 18 ref, 2 append,
 11  equ.

 Descriptors:   Water management  (applied), Irrigation programs, Model studies,
 Wells,  Evapotranspiration,  Net  profit, Economic prediction, Growth stages,
 Timing,  Groundwater.

 A method was  developed  to predict optimal and acceptable suboptimal well capacities
 using  a  model developed at  the  University of California, Davis.  Net revenue values
 were calculated at various well capacities using  a budget for a 132-acre field and
 an  equation  for determining yield reduction.   The well  capacities were chosen based
 on  growth  periods found to have  a differential impact on corn yields.   These
 differential  effects were discussed  in terms of the optimal and suboptimal well
 capacities  that will fulfill water requirements through certain parts  of the growth
 season.  This model may provide  a farmer with a predictive tool so that he may
 consider optimally timed water  application by an optimal well capacity to maxi-
mize net revenue.  In addition,  it may provide information for policy  makers to
 enact  regulations, which would make  the use of groundwater resources more bene-
 ficial  to  the  society.


 78:068-010
 SOCIAL  COSTS  AND EFFECTIVENESS OF ALTERNATIVE NONPOINT POLLUTION CONTROL PRACTICES,
Alt, K.F., Miranowski, J.A., and Heady,  E.O.
 Economics, Statistics, and Cooperatives Service, United States Department of
Agriculture, Ames, Iowa.
Proceedings of the 1978 Cornell Agricultural  Waste Management Conference, p 321-
 327.   1 tab,  11 ref.

Descriptors:  Water pollution control, Water quality  control, Water pollution,
Social aspects, Cost comparisons, Cost-benefit analysis, Alternative costs,
Social  impact, Environmental control.


                                     243

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A study was undertaken  to estimate the magnitude of the farm production cost
adjustments that would  result from implementing specific environmental policies
in  an  intensively cropped river basin of about 940,000 acres in East-Central
Iowa.  A linear programming model was used to simulate the crop growing and
erosion management activities of the area.  An exponential abatement cost
function resulted for the total cost of reducing the sedimentation rate of a
reservoir at the mouth  of the watershed.  Some of the pollution control policies
considered in the study did not restrict the farmer's choice to that particular
crop management system  which was most effective from an engineering standpoint.
It  was concluded that the choice of future pollution control policies needs to
be  based on the costs changes incurred by farmers as well as the administration
and surveillance costs  incurred by the public agency which administers the
pollution policy, and therefore, a truly optimal choice among alternative
pollution control policies can only be made when the total of all public and
private costs is weighed against the total of all benefits received.


78:06B-011
THE ECONOMIC IMPLICATIONS OF EROSION AND SEDIMENTATION CONTROL PLANS FOR SELECTED
PENNSYLVANIA DAIRY FARMS,
White, G.B., and Partenheimer, E.J.
Cornell University, Ithaca, New York, Department of Agricultural Economics.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 341-
357.  6 tab, 8 ref.

Descriptors:  Erosion control, Sediment control, Economic impact, Dairy industry,
Water law, Soil conservation, Linear programming, Pennsylvania.

Amendments to the Clean Streams Law of Pennsylvania required the state's
agricultural landowners to have erosion and sedimentation control plans imple-
mented by July 1, 1977.  The purpose of this research was to investigate the
effects of implementation on the income of commercial dairy farms.  The research
focused on conservation plans made by the Soil Conservation Service (SCS) for
twelve case study farms.  Linear programming was used to estimate returns to
fixed resources and farm organization for three plans for each farm.  These in-
cluded the base plan, before implementation of the SCS plan; the farm plan incor-
porating SCS recommendations; and a plan incorporating no-till corn production
as  an alternate or supplement to other conservation practices.


78:06B-012
FARM-LEVEL ECONOMIC EVALUATION OF EROSION CONTROL AND REDUCED CHEMICAL USE IN
IOWA,
McGrann, J.M., and Meyer, J.
Iowa State University, Ames, Department of Economics.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 359-
372.  1 fig, 3 tab, 11  ref.

Descriptors:  Erosion control, Fertilizers, Pesticide toxicity, Water pollution
sources, Economic impact, Model studies, Linear programming, Terracing,
Institutional constraints, Iowa.

This study concentrated on the farm-level economic impact of soil loss control
and reduced chemical use.  The farms analyzed are typical of three major soil
associations in Iowa which cover a wide spectrum of farming conditions in the
state.  The analysis investigated the impact of restricting soil loss from the
present to several reduced levels on net farm.income and land rents for both
specialized crop and mixed crop and livestock farms.  The waste disposal pro-
blem of the limited sized livestock enterprises was not addressed in this study.
A limited analysis was made of the effect that reducing fertilizer and banning
pesticide use would have on farm income as an alternative to reduce nonpoint
pollution.   Policy alternatives to control erosion, including tax rates to
achieve reduced soil loss and cost-sharing schemes for terracing, were evaluated
in farm-level models.  Consideration was also made as to how information generated
in the study can be used for extensionist and farmer training.
                                     244

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78:068-013
ECONOMIC IMPACTS OF POLICIES TO CONTROL EROSION AND SEDIMENTATION IN ILLINOIS
AND OTHER CORN-BELT STATES,
Seitz, W.D., Osteen, C., and Nelson, M.C.
Illinois University, Urbana, Institute for Environmental Studies.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference,
p 373-382.  10 ref.
(See 78:05G-058)


78:068-014
PROCEDURE FOR ECONOMIC EVALUATION OF BEST MANAGEMENT PRACTICES,
Dempster, T.H., and stierna, J.H.
United States Department of Agriculture, Soil Conservation Service, Washington,
D.C.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference,
p 383-391.  1 fig, 1 tab, 3 ref.

Descriptors:  Soil conservation, Soil erosion, Management, Economic impact,
Environmental effects, Water pollution, Water pollution control, Water quality,
Water quality control.

Evaluation procedures for best management practices (BMP) were discussed with
emphasis on alternative practices affecting water conservation and quality, and
production efficiency.  Onsite and offsite resource problems that were identified
and measured, include those related to reduced agricultural production and in-
creased production and maintenance costs per unit of output which can result
from erosion, sedimentation, impaired water quality and reduced soil moisture.
Quantified data from the use of universalt soil loss equation, research studies
of extension, universities and Agricultural Research Services (ARS), and com-
piling of experienced crop yields were evaluated with computerized methods such
as the Crop Budget System (CBS), linear programming and value of agricultural
production.  CBS is a system designed for efficient storage, rapid retrieval,
use and revision of crop budgets used to evaluate alternative systems of BMP.
Qualifying statements on nonmonetary impacts, primarily environmental issues,
were also discussed.  Procedures describing the estimation of installation,
operation and maintenance costs of BMP were included, as well as methods to
assess income foregone and adverse environmental effects.


78:068-015
AN ECONOMIC ANALYSIS OF EROSION CONTROL OPTIONS IN TEXAS,
Reneau, D.R., and Taylor, C.R.
Texas ASM University, College Station) Department of Agricultural Economics.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 393-
418.  4 fig, 8 tab, 11 ref.

Descriptors:  Erosion control, Soil erosion, Economic impact, Sediment control,
Water pollution, Water pollution control, Water quality, Water quality control,
Model studies, Texas.

A model for estimating the changes in farming practices, farm income, soil loss,
off-site sediment damages, and social welfare over a long planning horizon for
a watershed under various nonpoint source control options was presented.  The
model was sufficiently general to permit the study of several possible nonpoint
source control options, including:  (a)  per acre soil loss limits; (b)   soil
loss taxes; (c)  conservation practice cost sharing arrangement; and (d)  combi-
nations thereof.  On-farm economics of conservation was imbedded in the model.
Results from this modeling approach for Lavon Reservoir Watershed were presented.
Included were the esimated changes in farming practices, farm income, soil loss,
and off-site sediment damages for the selected nonpoint source control options.


78:068-016
MODELING SOIL AND WATER CONSERVATION PRACTICES,
Beyerlein, D.C., and Donigian, A.S.
Hydrocomp, Incorporated, Palo Alto, California.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 687-
713.  9 fig, 4 tab, 16 ref, 5 equ.
 (See  78:056-065)

                                      245

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 78:06B-017
 MODELING NUTRIENT EXPORT  IN RAINFALL AND SNOWMELT RUNOFF,
 Haith,  D.A., and Tubbs, L.J.
 Cornell University, Ithaca, New York, Departments of Agricultural Engineering
 and Environmental Engineering.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 665-
 685.   3 fig, 11 tab,  22 ref, 19 equ.

 Descriptors:  Nutrient removal, Agricultural watersheds, Mathematical models,
 Agricultural runoff,  Model studies, Snowmelt, Water quality, Water pollution,
 New York.

 Several mathematical  models are available for the prediction of nutrient losses
 from agricultural watersheds.  Most models have complex structures, require
 large  computer programs and data banks and must be calibrated using streamflow
 data.   There are obvious  advantages, at least for planning purposes, in simpler
 modelling approaches  with modest data and computational requirements.  One such
 approach, which was evaluated in this paper, is the estimation of runoff from
 each unit source area within a watershed, multiplication of these runoff esti-
 mates  by appropriate  nutrient concentrations and summing the resulting mass fluxes
 for all source areas  in the watershed.  The approach is roughly equivalent to a
 distributed watershed model in which all flows are instantaneously routed to the
 watershed outlet.  Mass fluxes of dissolved nitrogen, dissolved phosphorus and
 total  phosphorus from agricultural runoff were estimated for each storm during
 a period of 18 months in  1972-1974 for the Fall Creek Watershed in upstate New
 York.   The nutrient flux  estimates were compared with measured nutrient exports
 from the watershed determined from water quality samples.


 78:068-018
 MATHEMATICAL MODELING OF WATER QUALITY EFFECTS OF AGRICULTURAL BEST MANAGEMENT
 PRACTICES,
 Tang,  C.
 URS Company, Seattle, Washington.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 625-
 647.   6 fig, 5 tab, 5 ref.
 (See 78:05G-066)


 78:06B-019
 EVALUATION OF CONTROLS FOR AGRICULTURAL NONPOINT SOURCE POLLUTION,
Wineman, J.J., Walker, W., Kuhner, J., Smith, D.V., and Ginberg, P.
 Meta Systems, Incorporated, Cambridge, Massachusetts.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 599-
 624.   8 fig, 5 tab, 10 ref.

 Descriptors:  Water quality,  Methodology, Assessments, Model studies, Alternative
 planning, Water pollution, Water quality control, Evaluation.

A proposed methodology for assessing the water quality and socioeconomic impacts
 of agricultural practices was described and tested in a case study based on
 corn belt farming in northeastern Indiana.   The potential use of the methodology
 to evaluate agricultural nonpoint source pollution control policies and the
 effects of alternative futures was illustrated.   The development of such a
methodology for state level planning appeared feasible and to be of significant
value  for broad analyses of large numbers of policy alternatives, including
 identification of Best Management Practices.  However, the methodology was at a
preliminary stage of development when this report was presented.


 78:066-020
WATER QUALITY MODELING IN THE DELAWARE COASTAL PLAIN REGION,
Ritter, W.F., and Jensen,  P.A.
Delaware University,  Newark,  Department of Agricultural Engineering.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 507-
 524.  7 fig, 3 tab,  24 ref.

Descriptors:  Agricultural runoff, Model studies, Water quality, Water pollution,
Nitrogen,  Simulation analysis, Storm runoff, Nitrogen cycle, Coastal Plains,
Delaware.

                                      246

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A study of nonpoint modeling and the effect nonpoint sources have on water quality
was conducted for the Coastal Sussex County 208 Water Quality Program.  The EPA
Agricultural Runoff Model was used in1conjunction with a one dimensional water
quality model of eleven parameters (NH-N, NO2-N, N03-N, phytoplankton-N, benthic
N, herbivore N,  particular orgarfic N, dissolved organic N, ultimate BOD, dissolved
oxygen and total coliform) to analyze the effects of land use changes on water
quality.  The ARM Model and water quality model were used in Indian River Bay,
Little Assawoman Bay, Rehoboth Bay and the Broadkill River.  The ARM Model gave
satisfactory results for nitrogen and phosphorus nonpoint source loads.  A
simulation study indicated that there would be no major water quality effects
resulting from 20 year projected increases in urban areas or other land use
changes.



METHODOLOGIES FOR VALUATION OF AGRICULTURAL CROP YIELD CHANGES—A REVIEW,
Leung, S., Reed, W., Cauchois, S., and Howitt, R.                     ,.f.
Eureka Laboratories, Incorporated, 401 N. 16th Street, Sacramento, California

Publication No. EPA-600/5-78-018, August, 1978.  167 p,  5 fig,  3 tab, 433 ref.

Descriptors:  Crop  production,•Economic  impact, Economic prediction,  Yield
equations, Model studies, Methodology, Reviews, Pollutants, Air pollution,
Agriculture.

This  research effort was  initiated with  the objective  to complete a review  and
evaluation of the methodological and  analytical techniques used to assess and
quantify  the economic  impact of changes  in agricultural  crop yields.  The review
focused on two major areas:   (1)  physical effects of man-made  and natural
factors on agricultural crop yield, and  (2)  methodologies and  models used  to
evaluate  and quantify  the economic impacts of crop yield changes on the farm,
the agricultural industry and  finally the consumers.   The major natural environ-
mental  factors included in this report are climate and weather, soil  and biological
conditions   Air pollution was the main  consideration  under the man-made factors.
Three alternative models  were  identified for the evaluation of  the cost to  an
individual farm due to changes in crop yield.  These models are (a)   mathematical
optimization model, (b)   simulation model, and  (c)  econometric model.   Also
outlined  were the regional input-output  model and the  regional  spatial  programming
model as  two feasible  approaches  in  evaluating  the secondary economic impacts.
Finallv   the market supply and demand theories were identified  as  relevant  con-
cepts in  analyzing  the overall impacts on consumers due  to crop yield changes.


78:06B-022
AN EVALUATION OF THE POTENTIAL FOR USING DRAINAGE CONTROL TO REDUCE NITRATE LOSS
FROM  AGRICULTURAL FIELDS  TO SURFACE WATERS,
Gillian,  J.W., Skaggs, R.W., and Weed, S.B.
North Carolina State University, Raleigh, Department of  Soil Science, Agricultural

wSJrResources1 Research  Institute Report No. 128, PB  280 575,  January,  1978.
108 p, 23 fig, 4 tab,  32  ref,  3 append.
(See  78:050-074)
                                      247

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                                  SECTION XXVII


                          WATER RESOURCES PLANNING

        COST ALLOCATION, COST SHARING, PRICING/REPAYMENT (GROUP 06C)


78:06C-001
DRAINAGE INSTALLATION EQUIPMENTS "ECONOMICS OF THE ART",
Marsee, C.W.
Speicher Corporation, Celina, Ohio.
Paper No. 78-2527, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 9 p.

Descriptors:  Drainage, Subsurface drains. Equipment, Trenches, Installation,
Costs, Return (monetary), Investment, Economics.

There are two objectives being brought out of the "Economics of the Art" on
Drainage Equipment.  First, to make the drainage contractor more aware of his
cost of operation and his return on investment.  Second, to illustrate the cost
of operation and return on investment between the wheel and chain trenching
machines.


78:06C-002
SOCIAL OVERHEAD CAPITAL COSTS OF IRRIGATION DEVELOPMENT IN WASHINGTON STATE,
Whittlesey, N.K., Gibbs, K.C., and Butcher, W.R.
Washington State University, Pullman, Department of Agricultural Economics.
Water Resources Bulletin, Vol. 14, No. 3, p 663-678, June,  1978.  2 fig, 4 tab,
7 ref.

Descriptors:  Irrigation, Energy, Social impact. Costs, Washington, Irrigation
effects. Water resources development, Columbia river.

Increased irrigation as a means of achieving economic development can impose
significant social costs on the state or region of growth.   The growth in
population induced by additional irrigation will require roads, water and sewage
facilities, schools, fire and police protection, etc.  Also the increased energy
demands due to irrigation and growth in economic activity must be met.  Capital
investments required to service these needs of new development can become very
large.  This study attempted to measure such social overhead costs or irrigation
development for some specific irrigation project areas of Eastern Washington.
It was shown that investment costs in overhead items can reach $2,000 per acre
irrigated or $70,000 per job created.  Alternatively, the annual costs can equal
$180 per acre or $6,700 per worker.  These costs must be paid locally through
increased taxes, utility rates, or costs for services.
                                     243

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                               SECTION XXVIII


                          WATER RESOURCES PLANNING

                          WATER DEMAND (GROUP 06D)


78:060-001
REMOTE SENSING OF AGRICULTURAL WATER DEMAND INFORMATION:  A CALIFORNIA STUDY,
Estes, J.E., Jensen, J.R., and Tinney, L.R.
California University, Santa Barbara, Department of Geography.
Water Resources Research, Vol. 14, No. 2, p 170-176, April, 1978.  3 fig, 3 tab,
8 ref.

Descriptors:  *Reraote sensing, *Water demand, "Computer models, *Groundwater
basins, *California, Agriculture, Crops,  Statistics, Prediction, Simulation
analysis.

This study focuses on the use of LANDSTAT image-processing techniques to produce
cropland and crop type statistics for input into agricultural water demand pre-
diction procedures currently being employed by the Kern County Water Agency in
Kern County, California.  The potential of remote sensing to provide input to
the Kern County Water Agency's groundwater basin model in a more accurate and
timely fashion is the objective of the research discussed herein.  Current
accuracies associated with LANDSTAT cropland/noncropland identifications are of
the order of 98% absolute accuracy.  These data are being operationally incor-
porated into model calculations on a quarterly basis.  Crop specific accuracies,
although somewhat lower, are steadily being improved, and prospects for eventual
incorporation appear good.  The model, which divides the San Joaquin Valley
floor portion of the Kern County groundwater basin into 251 nodal regions, is
designed to produce a total simulation of water transmission and storage through-
out the model area; it incorporates detailed, relatively' stable geologic infor-
mation in conjunction with the capabilities provided by remote sensing, the
potential exists to sample current information continually for both short-term
and long-term agricultural water demand forecasting.


78:060-002
ANALYSIS OF WATER REQUIREMENTS FOR AGRICULTURAL IRRIGATION IN PENNSYLVANIA,
Kibler, D.F., Fritton, D.D., White, E.L., Trotter, R.J., and Tandy, D.F.
Pennsylvania State University, University Park, Institute for Research on Land
and Water Resources.
Research Publication 99, September, 1977, 228 p.  28 fig, 35 tab, 6 ref.

Descriptors:  *Crop production, *Climates, *Irrigation water, *Soil moisture,
*Water demand, *Water requirements, *Pennsylvania, Irrigation, Application
methods, Crops.

The objective is to identify the crops which are likely to be irrigated under
Pennsylvania's climatic conditions.  The decisions are made on the basis of
the historical use of irrigation for crops as documented in census records and
on the basis of published irrigation research experiments and other carefully
documented investigations which apply.  The attempt is to base decisions on
documented yield increases of a crop under irrigated conditions when compared
to yields produced by natural rainfall.  The specific purpose of this investi-
gation has been to develop quantitive estimates of expected irrigation demand
by analyzing the frequency distribution of rainfall, effective precipitation
and soil moisture deficit as they vary by crop and location throughout the State.
Frequency analysis of these irrigation parameters is based upon an extensive
data base describing the hydrologic, climatologic, and agronomic conditions
found at 65 potential irrigation sites located in the primary agricultural
areas of the State.  All data were analyzed by computer methods to obtain fre-
quency estimate of soil moisture deficit by crop and region.  The soil moisture
deficit is a primary indicator of irrigation need which can be used to project
future irrigation demands in Pennsylvania.
                                     249

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                                     SECTION  XXIX


                               WATER RESOURCES  PLANNING

                         WATER LAW  AND  INSTITUTIONS  (GROUP  06E)


 78:06E-001
 WESTERN WATER  LAWS  AND  IRRIGATION  RETURN FLOW,
 Radosevich,  G.E.
 Resources Administration and  Development,  Incorporated, P.O. Box  1028, Fort
 Collins, Colorado   80522.
 Publication  No. EPA-600/2-78-180,  August,  1978.   257 p, 5  fig,  3  tab, 107 ref,
 1  append.

 Descriptors:   Water law. Water rights.  Irrigation,  Irrigated land, Water
 pollution, Water quality.

 The  impact of  water law upon  allocation and use of waters within  the Western
 United States  is currently recognized  as one of the major  constraints to adapta-
 tion by irrigated agriculture of more  efficient operation  practices.  This pro-
 ject provides  a background of the  law  and  evaluation of the potentials through
 water law interpretations or  changes to implementing improved water management
 technology.  Specifically, this report provides a synthesis of water laws of
 each of the  17 western  states, as  well  as  providing a state-by-state account of
 the  water quantity  laws, paying particular attention to features  in the laws
 and  their administration that direct the manner of use and provide incentives
 or disincentives to more efficient use.  General recommendations  are offered
 that will permit or induce more efficient  and effective water management.
 Specific recommendations identify  areas requiring additional research to reno-
 vate state water laws consistent with  present and prospective policies and needs.


 78:06E-002
 ALTERNATIVE POLICIES FOR CONTROLLING NONPOINT AGRICULTURAL SOURCES OF WATER
 POLLUTION,
 Seitz, W.D., Gardner, D.M., Gove,  S.K., Guntermann, K.L., and Karr, J.R.
 Illinois University, Urbana-Champaign,  Urbana, Illinois  61801.
 Publication No. EPA-600/5-78-005,  April, 1978.  314 p, 22 fig, 55 tab, 168 ref,
 8 append.

 Descriptors:  Water pollution, Soil erosion, Economics.

 This study of policies  for controlling water pollution from nonpoint agricultural
 sources includes a  survey of  existing state and Federal programs, agencies, and
 laws directed to the control  of soil erosion.  Six policies representing a variety
 of approaches to this pollution problem are analyzed.  The aggregate economic
 impact of such policies is investigated using a state-of-the-art, market-equili-
 brium, linear-programming model of crop production in the corn belt.  The economic
 effects of the policies at the level of individual forms and their impacts on
 long-term soil productivity are analyzed through the use of a watershed model.
 The  institutional arrangements needed to implement the policies are examined, as
 are  the associated  costs for  a typical county.  Literature on the social aspects
 of policy acceptance is reviewed, and the results of a survey of the reaction of
 farmers and ASCS directors in Illinois  to different policies are presented.  The •
 equity of the policies  is examined and  legal precedents are reviewed.


 78:06E-003
 AN ANALYSIS OF PLAYA LAKE WATER UTILIZATION ON THE TEXAS HIGH PLAINS,
 Templer, O.W.
 Texas Tech University, Lubbock, Department of Geography.
Water Resources Bulletin, Vol. 14,  No.   2,  p 454-465, April, 1978.  3 fig, 34 ref.
                                     250

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 Descriptors:  Water utilization, Playas, Texas, Semi-arid climates, Water rights,
 Water  law, Groundwater recharge, Runoff, Groundwater, Irrigated land.

 This paper examines the spatial, temporal and legal aspects of playa lake water
 utilization on  the semi-arid Texas High Plains.  These small basins of interior
 drainage  collect and briefly hold an estimated two to three million acre-feet of
 runoff water annually, representing from one-fourth to one-third the quantity of
 groundwater pumped from the dwindling Ogallala aquifer.  Once considered a detri-
 ment to farming operations, there is now increased interest in using playa water
 more effectively.  At present direct pumping is the chief method of utilization,
 and modification of lake bottoms to concentrate runoff and reduce evaporation is
 the most  widespread conservation practice.  The use of playa water for ground-
 water  recharge  is hampered by as yet unsolved technical problems.  For many years,
 the question of ownership of playa water remained unsettled.  The Texas Water
 Rights Commission now classes it as diffused surface water, which under Texas law
 may be used by  the landowner, though some legal problems remain.  For playa
 lakes  to  be effectively integrated into the regional water resource it becomes
 imperative that all present and prospective water utilization problems be
 identified and  resolved.


 78:06E-004
 208 WATER QUALITY PLANNING HOW IT WILL AFFECT YOU,
 Humenik,  F.J.
 North Carolina State University, Raleigh, United States Department of Agriculture.
 Irrigation Journal, Vol. 28, No. 3, p 6-7, 17, 24, 25, May-June, 1978.

 Descriptors:  Water law, Water pollution control, Water pollution, Water
 pollution sources, Waste water disposal, Waste water treatment. Water quality
 act, Water quality control, Water resources planning act, Planning.

 208 is actually a section of Public Law 92-500, the Federal Water Pollution
 Control Act Amendment of 1972.  General goals of this sweeping legislation are
 to restore and maintain the chemical, physical, and biological integrity of the
 Nation's  waters.  A comprehensive discussion of "Section 208" is presented in this
 article.


 78:06E-005
 NON-POINT POLLUTION AND THE SCS,
 Agricultural Engineering, Vol. 59, No. 5, p 19-20, May, 1978.

 Descriptors:  Water pollution, Water pollution sources. Water pollution control,
Water quality act, Pollution abatement, Soil conservation, Legal aspects,
 Agricultural engineering.

Agricultural Engineering interviews Glen H. Loomis, PE, director of the Environmen-
 tal Services Division of USDA-SCS, on the Culver Amendment to the Clean Water Act.


 78:06E-006
 INTERNATIONAL PROBLEMS,
Holburt,  M.B.
Values and Choices In the Development of The Colorado River Basin, The University
 of Arizona Press, Tucson, Arizona, 1978, p 220-237.  2 fig, 1 tab, 11 ref.

 Descriptors:  Colorado River, Colorado River Basin, Water quality act, Water
quality,  Water quality control, Water pollution control, Mexican Water Treaty,
 Legislation, Salinity.

This paper discusses the Colorado River water quality and quantity problems
between the United States and Mexico, considerations that have led to the several
 agreements between the two countries, and possible future actions,


 78:06E-007
THE LEGALIZATION OF GROUNDWATER STORAGE,
Gleason,  V.E.
Southern  California Metropolitan Water District, Los Angeles.
Water Resources Bulletin, Vol. 14, No. 3, p 532-541, June, 1978.  1 fig, 16 ref.

                                     251

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 Descriptors:   *Water law,  *Water rights, *Appropriative rights, *California,
 *Water storage, Legal aspects, Aquifer management, Judicial decisions, Groundwater,
 Water supply.

 California courts recently recognized underground aquifer storage rights that
 allow public agencies to store imported waters in aquifers, to prevent others from
 expropriating  that water, and to recapture that water when it is needed.  The two
 appellate decisions representing the common-law development of aquifer storage
 rights are discussed.  One decision, entitled Niles Sand and Gravel Company vs.
 Alameda County Water District 37 C.A. 3d 924 (1974), involved an aquifer managed
 under statutory authority, while the other, City of Los Angeles vs. City of San
 Fernando 14 Cal. 3d 199 (1975) , dealt with an aquifer managed under judicial
 authority.  These decisions offer two rationales for aquifer storage rights:  (1)
 to protect water supplies necessary for the overlying community, and (2) to
 increase water supply efficiency by using natural underground storage whenever
 possible.  This paper analyzes the relationship between aquifer storage rights and
 conventional groundwater rights, indicating aspects of storage rights that need
 further development.


 78:06E-008
 A PROGRAM TO PROMOTE IRRIGATION CONSERVATION IN IDAHO,
 Hammond, J.
 State of Idaho, Statehouse, Boise, Department of Water Resources.
 Pacific Northwest Regional Commission, March, 1978.  43 p, 6 fig, 12 ref.
 (See 78:03F-107)


 78:06E-009
 NORTH CAROLINA 208 CASE STUDY,
 Horney, L.F., Koehler, F.A., and Bliven, L.F.
 North Carolina State University, Raleigh, Department of Biological and Agricultural
 Engineering.
 Paper No. 78-2584, Presented at the 1978 Winter Meeting of the American Society of
 Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago, Illinois,
 6 p.  4 ref.

 Descriptors:  Water pollution. Water quality, Water pollution control, Water
 quality control. Planning, Water management (applied), Water law, Legislation,
 Agriculture, North Carolina.


 The North Carolina approach for the development of the agricultural portion of the
 statewide 208 plan has been influenced by unanswered questions concerning actual
water quality and relationships between agricultural practices, conservation techni-
ques and areawide water quality.  The planning organization and responsibilities,
approaches and studies undertaken leading to plan recommendations were discussed
 in this paper.


 78:06E-010
 NONPOINT SOURCE POLLUTION CONTROL STRATEGY,
 Groszyk, W.S.
Water Planning Division, United States Environmental Protection Agency, Washington,
 D.C.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 3-10.

 Descriptors:  Water pollution control, Water pollution. Water quality. Water
quality control. Federal water pollution control act.  Water quality act, Water
 law. Management.

 This paper discussed the two major elements of the U.S. Environmental Protection
Agency's nonpoint source (NPS) pollution control strategy, and how two amendments
 in the Clean Water Act of 1977 provide with additional ways to implement NPS
 control programs, and thus solve some of the critical water quality problems.  These
 two major elements of EPA's nonpoint source control program were described to be:
 (1)  to accelerate the implementation of NPS control programs and the application
 of Best Management Practices  (BMP's) and, (2)   to focus the available resources
 on solving the most severe problems first.  This paper discussed these elements
 in details.

                                     252

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 78:06E-011
 RESEARCH  NEEDS AND  CURRENT ACTIVITIES,
 Murphy, T.A.
 Office of Research  and  Development, United States Environmental Protection Agency,
 Washington, D.C.
 Proceedings of the  1978 Cornell Agricultural Waste Management Conference, p 25-30.

 Descriptors:  Water pollution, Water quality control, Water management  (applied),
 Soil  conservation,  Water conservation, Management, Federal project policy,
 Mathematical models, Environmental control.

 This  paper focused  on broad topics regarding the renewable resources industry,
 including the current concerns, issues, and emerging environmental problems.  The
 role  of EPA in agricultural research was discussed in terms of both the nature and
 extent of our activities, within the context of cooperation with the agribusiness
 community.  Reliance on typical soil.and water conservation measures as best manage-
 ment  practices for  maintenance of water quality was viewed from the perspective
 of present technical knowledge and system assessment capabilities.  Additional
 studies necessary to confirm the link between water quality and best management
 practices were suggested.  It was suggested that improved monitoring techniques,
 instream  water quality  surveys, and a better understanding of sediment/pollutant
 adsorption and desorption mechanisms are required in the near future to sharpen
 the guidelines for  establishing agricultural nonpoint source management systems.
 Needed area-wide pollution problem assessment methodologies, BMP field evaluation,
 mathematical modeling of transport phenomena, and predictive techniques for BMP
 system comparisons  were outlined.  The projected extent of EPA/ORD involvement
 in these  future activities was examined in light of potential resource availability
 and was compared with similar activities in other Federal, State, and local
 agencies  and institutions.


 78:06E-012
 CONSERVATION DISTRICT INVOLVEMENT IN 208 NONPOINT SOURCE IMPLEMENTATION,
 Williams, R.E., and Lake, J.E.
 National  Association of Conservation Districts/ Washington, D.C.
 Proceedings of the  1978 Cornell Agricultural Waste Management Conference, p 57-67.
 (See  78:05G-048)


 78:06E-013
 MANAGEMENT AND FINANCING OF AGRICULTURAL BMPs,
 Rice, J.M.
 URS Company, Seattle, Washington.
 Proceedings of the  1978 Cornell Agricultural Waste Management Conference, p 329-
 340.  2 fig, 1 tab, 5 ref.

 Descriptors:  Water quality control, Water quality, Water pollution, Planning,
 Management,  Agricultural runoff, Water pollution sources, Water pollution con-
 trol, Programs, Washington.

 One of the major goals  of the Section 208 areawide waste management planning
 program,  mandated by PL 92-500 and administered by the U.S. Environmental Protec-
 tion Agency (EPA),  is to develop solutions to identified water pollution problems
which can and will  be put into practice.  The agricultural program developed in
 SNOMET/King County  (Washington)  represents one approach to implementing nonpoint
water pollution control measures which both satisfies the technical and other
 requirements of EPA concerning water quality management and satisfied the more
 pragmatic requirements  of working farmers who are concerned both about making a
 living and about conservation.  This paper presented the results of that program
with special emphasis on unique aspects of the social and political setting of
 the SNOMET/King County  area.   The implemented program is in one sense no
 different than those developed in many other agricultural areas of the country;
 yet its acceptance  by the local farming community and their willingness to
participate in implementation of the program represent an institutional achieve-
ment in itself.  Process,  not product,  then was a major focus of this paper.
                                     253

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 78:06E-014
 THE POLICY RELEVANCE OF ALTERNATIVE INSTITUTIONAL APPROACHES TO 208 PLANNING,
 Hamilton, A., and Libby, L.W.
 Michigan State University, East Lansing, Department of Agricultural Economics.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 419-
 428.   4 tab, 3 ref.

 Descriptors:  Water quality control, Water quality act, Water pollution, Planning,
 Decision making, Alternative planning, Water quality, Local governments.

 The power to implement many of the best management practices to control nonpoint
 pollution being considered in 208 planning lies with local governments  (county,
 city,  town, village).  But the planning for reduction of nonpoint sources of
 pollution, is being done at the regional (usually multi county) of the state level,
 The tradeoffs between coordination and implementation that occur at these two
 different institutional boundaries were examined in this paper.  It was believed
 that this research will have relevance not only to the water quality planning
 process but to a number of other planning exercises as well.  The paper has
 drawn preliminary conclusions on the policy relevance of the different planning
 models discussed.


 78:06E-015
 ECONOMIC, INSTITUTIONAL AND WATER QUALITY CONSIDERATIONS IN THE ANALYSIS OF
 SEDIMENT CONTROL ALTERNATIVES:  A CASE STUDY,
 Sharp, B.M.H., and Berkowitz, S.J.
 Wisconsin University, Madison, Department of Agricultural Economics.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 429-
 453.   6 fig, 8 tab, 20 ref, 6 equ.

 Descriptors:  Sediment control, Economic impact, Institutional constraints,
Water quality, Linear programming, Soil conservation, Sediment yield, Sediment
 load, Model studies, Decision making.

Traditional economic analyses of the impact of conservation policies on the farm
 firm have relied solely upon the establishment of soil loss constraints to
 induce compliance.  There are, however, different approaches to inducing a pattern
of behavior which are also consistent with achieving the desired reduction in
sediment.  These policy options also have differing economic,  institutional and
water quality implications.  The results of a study, conducted in a 440 acre water-
 shed in Washington County,  Wisconsin, which explicitly recognizes a set of institu-
 tional alternatives designed to modify operator behavior, were presented in this
paper.  In addition, the water quality implications of these alternatives with
respect to sediment loads were illustrated.


 78:06E-016
 INSTITUTIONAL AND TECHNICAL ASPECTS OF THE DEVELOPMENT OF AGRICULTURAL BMPs IN
 A FIVE-COUNTY RURAL/URBAN MICHIGAN REGION,
 Jones, J.P.,  and Sutherland,  J.C.
 Williams & Works, Incorporated,  Grand Rapids,  Michigan.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference,  p 455-
 462.   2 fig.
 (See 78:05G-059)


 78:06E-017
 DEVELOPMENT OF A "208 PLAN" FOR AGRICULTURAL NONPOINT POLLUTION SOURCES IN
 ILLINOIS,
 Vanderholm, D.H., Frank, J.F., and Taylor, A.G.
 Illinois University,  Urbana-Champaign, Department of Agricultural Engineering.
 Proceedings of the 1978 Cornell Agricultural Waste Management Conference,  p 563-
 580.
 (See 78:056-061)


 78:06E-018
 APPROACH FOR ANALYZING AND MANAGING AGRICULTURAL NONPOINT SOURCES IN THE STATE
 OF MARYLAND,
 Schoenhofer,  R.F., Knight, W.A., and Hancock, C.V.


                                       254

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Water Resources Administration, State of Maryland Department of Natural Resources,
Annapolis, Maryland.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 551-
561.  2 fig, 9 ref.
(See 78:05G-062)


78:06E-019
A STATE PERSPECTIVE ON NONPOINT SOURCE MANAGEMENT,
Berle, P.A.A.
New York State Department of Environmental Conservation, Albany, New York.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 17-24.
(See 78.-05G-068)


78:06E-020
IMPROVING WATER QUALITY IN AGRICULTURE AND SILVICULTURE,
Unger, D.G.
Agriculture for Conservation, Research and Education, United States Department of
Agriculture, Washington, D.C.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference, p 11-16.

Descriptors:  Water pollution, Water quality, Water quality control, Water
pollution control, Water law, Water management (applied), Programs, Federal water
pollution control act, Federal project policy, Federal government.

This paper reports the viewpoints of U.S. Department of Agriculture on America's
water quality needs and the programs designed to meet them,  it was stressed
that the overall job of upgrading water quality requires an effective combination
of good management, technical assistance, economic incentives, research and
education.


78:06E-021
POTENTIAL EFFECTS OF ENVIRONMENTAL POLICIES ON RESOURCE USE AND REGIONAL INCOMES
IN AGRICULTURE,
Vocke, G.F., and Heady, E.O.
Iowa State University of Science and Technology,  Ames, Iowa.
Agriculture and Environment, Vol. 4, No. 2, p 99-109, August, 1978.  1 fig, 6 tab,
8 ref.

Descriptors:  Agriculture, Crop production, Economics, Environment, Fertilizers,
Land management,  Land resources, Land use.

The results of this study indicate that U.S. agriculture can comply with restric-
tive environmental policies but not without significant consequences for farmers
and their incomes.  The imposition of a soil conservation policy alters crop
production patterns, changes the regional distribution of agricultural incomes,
and implies higher food expenses for consumers.   A restriction on the use of
nitrogen fertilizer requires substantial substitutes of other resources to main-
tain agricultural output.  However, regional production patterns are altered,
thus changing regional incomes from agriculture.   A ban on the use of the organo-
chlorine insecticides Chlordane and Haptachlor causes few major changes for
agriculture but there is the potential that the incomes of some Midwest corn
farmers may be drastically reduced by an insect infestation.  Requiring feedlot
operators to control the runoff from their feedlots will be particularly costly
for small livestock producers but does not significantly alter regional live-
stock production patterns.  Under high exports which are not restrained by
environmental measures, land used for crops increases by 67 million acres, fert-
ilizer use increases by 29 percent, and pesticide expenditures increase by 50
percent.  When the several environmental restrictions are applied simultaneously,
the value of exports must decline by 40 percent.   Accompanying the reduction in
exports is a 60 percent decline in soil erosion and a 30 percent reduction in
nitrogen use.
                                     255

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                                  SECTION XXX


                          WATER RESOURCES PLANNING


             ECOLOGICAL IMPACT OF WATER DEVELOPMENT (GROUP 06G)


78:06G-001
IRRIGATION MANAGEMENT SERVICE AND MOSQUITO CONTROL,
Hayes, R.O., and Nielsen, R.L.
Colorado State University, Fort Collins, Vector-Borne Diseases Division, Center
for Disease Control.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 104, No. IR2, p 153-163, June, 1978.  1 fig, 2 tab, 19 ref,
1 append.

Descriptors:  Irrigation programs, Mosquitoes, Irrigation practices, Vectors
(biological), Diseases, Disease resistence, Water management (applied), Crop
production. Water pollution, Irrigated land.

The importance of irrigation to the production of agricultural crops has led to
its widespread use throughout the  United States.  Mosquito production and
vector-borne diseases often have been problems in intensely irrigated areas,
but in some areas good irrigation water management practices have been shown
to minimize such problems.  The evaluation of the Mesa County, Colorado, Irrigation
Management Service (IMS) program found it associated with lower site and habitat
infestation rates only among the IMS orchard sites, whereas the IMS program was
not associated with reduced mosquito production among either alfalfa or corn
fields, and no mosquito production was found associated with sugar beet crops,
either in or out of the IMS program.  Although pastures were not included in
the IMS program, they were included in this evaluation, and a high percentage
of the pastures examined were associated with mosquito production.  The results
also revealed that the mosquito fauna, the principal types of mosquito larval
habitats, and the water sources for mosquito breeding in the irrigated areas
of Mesa County were nearly the same in 1975 as in 1959.


78:06G-002
AGRICULTURE AND CONSERVATION—ECOLOGICAL AND SOCIAL ASPECTS,
Hampicke, U.
Agriculture and Environment, Vol. 4, No. 1, p 25-42, April, 1978.  70 ref.

Descriptors:  Agriculture, Conservation, Ecology, Social aspects, Political
aspects. Pesticides, Planning, Economic impact.

The technological features and the economic and political repercussions were
discussed of an agricultural system which would meet strict conservation re-
quirements in central Europe, should they exist.  The rate and number of species
losses, classification of endangered species and destruction of environmental
variety were discussed.  It was suggested that the countryside be divided
systematically into areas of high productivity, and others where traditional
methods of land use are continued.  Three possibilities for protecting ecologically
valuable regions were discussed:  abolishing the use of pesticides, etc. al-
together; improved methods of crop spraying to prevent spray falling onto adja-
cent areas; and adaptation to unavoidable spray scattering by spatial structuring,.
i.e., installing buffer areas between productive and protected zones.  With re-
gard to the political and economic consequences of such a system, three indis-
pensable prerequisites were identified:  an adequate system of value judgments
in society; sufficient economic flexibility to allow changes; and proper means
of coordination, i.e./ economic planning.  It was concluded that gradual im-
provements on a local scale are possible and should be encouraged.


78:06G-003
ENVIRONMENTAL AND INSTITUTIONAL ASPECTS OF IRRIGATION AGRICULTURE,
van Schilfgaarde, J.
U.S. Salinity Laboratory, Riverside, California.

                                     256

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Paper No. 78-2045, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 6 p.  7 ref.

Descriptors:  Irrigation, Salinj>ty, Drainage, Institutional constraints, Environ-
mental effects, Social aspects, Irrigated land. Irrigation design, Water
management  (applied), Agriculture.

Irrigation agriculture requires drainage, but design options and water management
choices impact not only agricultural production.  A host of institutional and
societal considerations affect the viability of technically feasible alternatives.
Drainage, as an integral part of water management, must be viewed within this
larger framework and options identified that optimize total resource use.
                                     257

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                                 SECTION  XXXI

                               RESOURCES DATA

                          NETWORK DESIGN  (GROUP  OTA)


 78:07A-001
 LEARNING TO  IRRIGATE.  .  .WITH 5000 TENSIOMETERS,
 Henry, C.
 Irrigation Age, Northwest/Pacific Editor.
 Irrigation Age, Vol. 13,  No. 3,  p 6-8, November-December, 1978.  4 fig.

 Descriptors:  Tensiometers, Scheduling,  Irrigation, Idaho.

 This article reports the  experience of an irrigation consultant with the use
 of tensiometers for irrigation scheduling.


 78:07A-002
 PREDICTING IRRIGATION  RETURN FLOW RATES,
 Bondurant, J.A., Brockway, C.E., and Brown, M.J.
 United States Department  of Agriculture-Science and Education Administration,
 Brawley, California.
 Transactions of the American Society of Agricultural Engineers, Special Edition,
 Vol. 21SW, No.  6, p 1142-1143, December  20, 1978.  2 fig, 2 tab, 4 ref, 1 equ.

 Descriptors:  Return flow, Sediment load, Sediment distribution, Streamflow,
 Design flow, Irrigation.

 Return flows from irrigated areas in southern Idaho were analyzed and a
 relationship was developed that  characterizes flows by relating the cummulative
 percent of total seasonal flow to maximum flow rate.  Since maximum flow rate
 can be estimated from  channel characteristics and flow evidence, it was suggested
 that design flow rates' sediment ponds can be selected where flow records are
 not available.


 78:07A-003
 SPATIAL VARIABILITY OF SOLUBLE SALT CONTENT IN A MANGOS SHALE WATERSHED,
Wagenet, R.J., and Jurinak, J.J.
 Utah State University,  Logan, Department of Soil Science and Biometeorology.
Soil Science, Vol. 126, No. 6, p 342-349, December, 1978.  4 fig, 2 tab, 11 ref,
 4 equ.

 Descriptors:  Salinity, Saline water, Saline soils, Spatial distribution, Colorado
 River Basin, Water quality, Sampling, Statistical methods, Soil chemical properties.

A study was conducted  to examine data collected in the microwatershed land process
studies with regard to quantifying spatially variable soil properties.  All 35
sampling sites were classified as occurring on the Mancos shale formation within
a 777 sq km  (300 sq mi) area of the Price River Basin.  Samples were taken at 0-2.5,
 2.5-7.5, and 7.5-15.0-cm depths.  Using the electrical conductivity (EC) of either
the 1:1 or saturation extract as the salinity index parameter, it was found that
EC values were distributed log-normally about the mean EC value of 35 observations.
The coefficient of determination for the log-normal statistical plots was 1.00 for
all three depths sampled at the 35 sites.  The variance in the EC values increased.
with depth.
                                     258

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                                     SECTION XXXII


                                    RESOURCES DATA

                             DATA ACQUISITION (GROUP 07B)


 78:078-001
 ASSEMBLY FOR MOUNTING HYDRAULIC SOIL CORE SAMPLER ON TRACTOR FRONT,
 Ginn, L.H., Heatherly, L.G., and Russell, W.J.
 United States Department of Agriculture, Agricultural Research Service,
 stoneville, Mississippi.
 Soil Science Society of America Journal, Vol.  42, No. 3,  p 512-514, May-June
 1978.  4 fig, 6 ref.

 Descriptors:  Cores, Sampling,  Soil types,  Hydraulic equipment.

 A front-mounted tractor assembly for support of a hydraulic soil core sampler
 was constructed.   The design satisfies requirements for rapid soil or root
 core sampling.   An essential part of the assembly is a tool bar  which allows
 lateral movement of the mounted core sampler.   The assembly with mounted
 sampler is capable of extracting 1.9 to 10.2-cm diameter  cores to depths as
 great as 125 cm throughout a 102-cm lateral path.


 78:078-002
 IMPROVED TECHNIQUES FOR MARKING AND SAMPLING BAND-APPLIED FERTILIZERS AND
 PESTICIDES,
 Hendrickson, L.L.,  Keeney,  D.R.,  Lesczynski, D.B.,  and Walsh,  L.M.
 Wisconsin University,  Madison,  Department of Soil Science.
 Soil Science Society of America Journal,  Vol. 42, No.  3,  p 507-508,  May-June
 1978.   1 fig,  1 tab, 10 ref.

 Descriptors:  Nitrification,  Inhibitors,  Sampling,  Marking,  Techniques,  Nitrogen
 compounds.

 Techniques for  marking and  sampling banded  fertilizers  were  developed to estimate
 the rate of nitrification and the recovery  of N  from the  band  treated with a
 nitrification  inhibitor.  The band was  marked by applying  prilled elemental  S at
 the point of fertilizer application.   The sampler was  constructed of  stainless
 steel  and was  15 by 15 by 40  cm long.   It was inserted  into  the  soil  above the
 previously located  band and then  removed  and disassembled, and the soil  subsec-
 tioned for a vertical  profile of  constituents in the band.   The  expanded dimen-
 sions  of the sampler reduced  sample variability,  yet still allowed sufficient
 sampling efficiency to obtain adequate  replication.  These techniques  provided
 more  accurate estimates of  nitrification  and recovery of applied N and should
 find application in monitoring other fertilizers  or pesticides on easily  pene-
 trated soils devoid of rocks.


 78:078-003
 COLORIMETRIC DETERMINATION  OF UREA  IN SOIL EXTRACTS USING AN AUTOMATED SYSTEM,
 Douglas,  L.A,,  Sochtig,  H., and Flaig, W.
 Melbourne  University,  Australia,  School of Agriculture and Forestry.
 Soil Science Society of America Journal, Vol. 42, No. 2, p 291-292, March-April,
 1978.   1  fig, 1 tab, 2  ref.

 Descriptors:  Ureas, Coloriraetry, Analytical techniques. Inhibitors, Soil tests,
 Automation.

 A method  is  described  for using an automated system to determine urea  in 2M KCl
 soil extracts that  contain  a urease inhibitor (phenylmercuric acetate).  The
method is sensitive and precise and allows 90-120 extracts to be analyzed per day.


                                     259

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78:078-004
A NEW APPROACH TO SOIL TESTING: III.  DIFFERENTIAL ADSORPTION OF POTASSIUM,
Stout, W.L., and Baker, D.E.
Pennsylvania State University, University Park, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 2, p 307-310, March-April,
1978.  1 fig, 7 tab, 17 ref, 10 equ.

Descriptors:  Soil tests. Potassium, Cation adsorption, Nutrient requirements,
Cation exchange, Soil chemical properties. Regression analysis.

Donnan type ratios were used to develop an index to account for the differential
adsorption of K in two widely different soils of the Rayne and Hublersburg series.
This index was used to calculate an adjusted K requirement for the soils using
the approach of Baker.  Three corn hybrids (Zea mays L.) were grown in the two
soils treated with different levels of K and multiple regression analysis was
used to relate soil test variables to plant K content.  Most of the variation
in the index, K sub E/S, was associated with soil effects, making the index
useful in characterizing the two soils with respect to differential K adsorption
and in calculating soil K requirements.  Over 60% of the variation in plant K
content was explained by the soil K requirement calculated from the index.
Compared with a critical K level of 98 ppm exchangeable K for soils with a CEC
of 10 mez/100 g and a K sub E/S of 1.0, the comparable critical values for K
were 71 ppm for the Rayne and 114 ppm for the Hublersburg.


78:07B-005
QUANTITATIVE ESTIMATION OF LIVING WHEAT-ROOT LENGTHS IN SOIL CORES,
Ward, K.J., Klepper, B., Rickman, R.W., and Allmaras, R.R.
Columbia Plateau Conservation Research Center, Pendleton, Oregon, United States
Department of Agriculture.
Agronomy Journal, Vol. 70, No. 4, p 675-677,  July-August, 1978.  4 tab, 5 ref.

Descriptors:  Root development, Wheat, Dicots, Monocots, Sampling, Cores.

A rapid, efficient method for separating living wheat (Triticum aestivum L.) roots
from dead roots in field soil samples has been proposed.  Combined techniques of
separation, staining and length measurements were used to determine root density
with an accuracy of ^9%.  It was observed that most monocot roots stained more
intensely than dicot roots, indicating that monocot-dicot root separation from
the same root medium may facilitate studies of root competition.


78:078-006
MEASURING SYMBIOTIC NITROGEN FIXATION IN RANGELAND PLOTS OF TRIFOLIUM
SUBTERRANEUM L. AND BROMUS MOLLIS L.,
Phillips, D.A., and Bennett, J.P.
California University, Davis, Department of Agronomy and Range Science and
Vegetable Crops.
Agronomy Journal, Vol. 70, No. 4, p 671-674,  July-August, 1978.  3 fig, 1 tab,
16 ref.

Descriptors:  Nitrogen fixation, Range grasses, Legumes, Clovers, Range management,
Symbiosis, Isotop studies.

The 15N A-value technique and the acetylene reduction method were compared for
their accuracy in determining seasonal symbiotic N2 fixation on a ground area basis
in rangeland plots of Trifolium subterraneum L. and Bromus moHis L.  To simulate
range management practices, seeds-were planted at 10, 141, or 1970 seeds/sq m in
pure stands of 50:50 mixtures in Laughlin loam, a member of the fine-loamy, mixed,
raesic family of Ultic Haploxerolls.  Amounts of N2 fixed, calculated by the 15N
A-value technique, varied significantly with planting density and proportion of
clover at different densities.  Seasonal, symbiotic N2 fixation, calculated from
the acetylene reduction method, did not vary significantly with either planting
density or proportion of clover.  It is concluded that with appropriate studies
on possible differences in isotope accumulation by a grass and a legume, including
morphological, physiological, and bio-chemical differences, the 15N A-value
technique should be more quantitative and discriminatory than the acetylene
reduction technique.  The single seasonal sampling requirement of the 15N A-value
technique also is more amenable to the overall goal of determining the effect of
range management systems on symbiotic N2 fixation.

                                      260

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78:078-007
RELATIONSHIP BETWEEN LEAF AREA AND DRY MATTER IN WINTER WHEAT,
Aase, J.K.
Northern Plains Soil and Water Research Center, P.O. Box 1109, Sidney,
Montana  59270.                4
Agronomy Journal, Vol. 70, No. 4, p 563-565, July-August, 1978.  3 fig, 14 ref.

Descriptors:  Wheat, Leaves, Plant growth, Growth stages, Montana.

Models of plant growth and plant water use often require leaf-area measurements,
a potentially time-consuming and costly process.  The objective of this study
was to determine if by establishing a relationship between leaf area and dry
matter in winter wheat (Triticum aestivum L. em Thell), that dry matter can be
substituted for leaf area.  Four cultivars of winter wheat were seeded on Dooley
sandy loam .and Williams loam (fine-loamy, mixed, Typic Argiborolls) in northeastern
Montana in three divergent growing seasons.  Leaf area and dry matter determina-
tions, from random 30-cm row plant samples cut at ground level, were made weekly
throughout the season.  Leaf area and leaf dry matter were closely correlated
(coefficient of determination = 0.951).  Leaf area vs. plant dry matter also was
closely correlated (coefficient of determination = 0.948) through the fifth
growth stage (leaf sheaths strongly erect, tillering complete).  Thus it appears
that in studies and modeling efforts where leaf area indices are needed, at least
for winter wheat, leaf dry matter may be substituted for leaf  area index.


78:07B-008
THE AUTOMATIC DETERMINATION OF ppb LEVELS OF AMMONIA, NITRATE  PLUS NITRITE, AND
PHOSPHATE IN WATER IN THE PRESENCE OF ADDED MERCURY  (II) CHLORIDE,
Skjemstad, J.O., and Reeve, R.
Commonwealth Scientific and Industrial Research Organization,  St. Lucia,
Queensland 4067, Australia, Division of Soils.
Journal of Environmental Quality, Vol. 7, No. 1, p 137-141, January-March, 1978.
4 fig, 3 tab, 17 ref.

Descriptors:  Ammonia, Nitrates,  Nitrites, Phosphates, Preservation, Chemical
analysis.

Three automated procedures are reported for the simultaneous determination of
ammonia, nitrate plus nitrite, and phosphate in water.  The ammonia determina-
tion is based on the salicylate-dichloroisocyanurate reaction  in the presence
of nitroprusside preceded by in-line distillation.  Nitrate plus nitrite is
estimated by using an in-line copperized cadmium reductor, diazotizing the ni-
trite with sulphanilamide, and coupling with N-1-naphthylethylenediamine.
Phosphate is estimated by reaction with molybdate and reduction to molybdenum
blue with ferrous ammonium sulphate.  Mercury (II) chloride used as a preserva-
tive does not interfere with the methods and good precision at ppb levels can
be obtained.


78:07B-009
A NEUTRON ACTIVATION METHOD FOR DETERMINING SUBMICROGRAM SELENIUM IN FORAGE
GRASSES,
Cook, K.A., and Graham, E.R.
Missouri University, Columbia, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 1, p 57-60, January-
February, 1978.  1 fig, 5 tab, 7  ref.

Descriptors:  Fescues, Forage grasses, Neutron activation analysis, Radiochemical
analysis, Irradiation.

Neutron activation as a method for the analysis of submicrogram amounts of Se
in fescue and orchard leaves was  evaluated.  It was observed that the Se content
of National Bureau of Standards orchard leaves was 0.078 ppm compared with the
NBS reported value of 0.080 ppm Se.  The relative standard deviation for the
orchard leaves was found to be 5.3%.  Following irradiation and nitric-perchloric
acid digestion, Se was extracted  from a 4M HBr solution using benzene containing
1% phenol.  The method is sufficiently sensitive to measure with accuracy 0.010
ppm Se in 0.250 g of material.  The method is straightforward and accurate and
requires the extraction of Se in  benzene which is completely free of phosphorus.


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 78:078-010
 SODIUM BICARBONATE EXTRACTION TO ESTIMATE NITROGEN,  PHOSPHORUS,  AND POTASSIUM
 AVAILABILITY IN SOILS,
 Bar-Yosef, B,,  and Akiri,  B.
 Division of Soil Chemistry and Plant Nutrition,  Bet  Dagan,  Israel,  The
 Volcani Center.
 Soil  Science Society of America Journal,  Vol.  42,  No.  2,  p  319-323,  March-April,
 1978.   6 fig,  3 tab, 8  ref,  2 equ.

 Descriptors:   Soil analysis,  Soil chemical properties,  Soil tests.  Nitrogen,
 Phosphorus,  Potassium,  Calcareous soils.  Sodium  compounds,  Nutrients.

 The extractability of N03-N,  P,  and  K from five  calcareous  soils differing  in
 physical and chemical characteristics by  NaHCO3  (0.5M,  pH 8.5) was  studied  under
 laboratory conditions.  The  extracted amounts  of the three  ions  were related  to
 time  since their application  to the  soils,  to  the  equilibration  period of the
 soils  with the  extractants,  to the concentration of  the ions in  the soils,  and
 to the clay content of  the soils.  After  about 70  days  in the soil,  the extract-
 ability of each  ion at  a given application level was independent of  time.   The
 recovery percentage of  P and  K as  a  function of  the  applied amounts  of these
 elements depended mainly on  the clay content of  the  soils,  while NO3-N recovery
 was independent  of the  factors studied.   Linear  relationships were  obtained
 between NaHC03-  and NH4OAC-extracted K, and NaHC03-  and KCl-extracted  NO3-N.
 The slopes for  N03-N were  45  degrees for  all soils,  but were specific  for each
 soil  in the  case of K.


 78:073-011
 NEW FLUME BREAKTHROUGH  FOR DITCH  IRRIGATORS,
 Clemmens,  A.J.,  and Replogle,  J.A.
 United States Water Conservation  Laboratory, Science and  Education Administration,
 Phoenix,  Arizona.
 Irrigation Age,  Vol.  12, No.  7, p  82-88,  April,  1978.   3  fig,  3  tab.

 Descriptors:  Flumes, Equipment, Open channel  flow.  Flow  measurement,  Cost
 analysis.  Cost  comparisons, Critical flow.  Ditches,  Irrigation,  Arizona.

 New design methods  for  critical-flow flumes installed in  open channels  make on-
 farm flow measurement simple,  accurate, and inexpensive.  This paper describes
 the methods and  construction procedures used in  developing  a  new flume  to
 measure water flow in open channels.   The  cost analysis of  the eight flumes
 tested shows that the cost of  the  flume is very  inexpensive compared with other
 types  of flumes.   It also  claims  to  be precise within j^2%.


 78:07B-012
 DEVELOPMENT OF A DTPA SOIL TEST FOR  ZINC,  IRON,  MANGANESE,  AND COPPER,
 Lindsay, W.L., and  Norvell, W.A.
 Colorado State University, Fort Collins,  Department  of Agronomy.
 Soil Science Society of America Journal, Vol.  42, No. 3,  p  421-428, May-June,
 1978.   4 fig, 7  tab,  31 ref.

 Descriptors:  Chelation, Soil  tests,  Spectrophometry, Nutrients, Fertilizers,
 Sweet  corn, Sorghum,  Colorado.

 A DTPA soil test was  developed to identify near-neutral and  calcareous  soils
with insufficient available Zn, Fe,  Mn, or Cu for maximum yields of crops.
 The extractant consists of 0.005M DTPA, O.lM triethanolamine, and O.OlM CaC12,
with a pH of 7.3.   The  soil test successfully separated 77  Colorado soils on
 the basis of crop response to  Zn, Fe,  and Mn fertilizers.    Development of the
 soil test was based,  in part, on theoretical considerations.  The extractant
 is buffered at pH 7.30 and contains  CaC12 so that equilibrium with CaCO3 is
 established at a CO2  level about 10  times that of the atmosphere.  Thus, the
 extractant precludes dissolution of  CaC03 and the release of occluded nutrients
which  are normally not available to  plants.  DTPA was selected as the chelating
agent because it can effectively extract all four micronutrient metals.  Factors
 such as pH, concentration of chelating agent, time of shaking, and temperature
of extraction affect the amount of micronutrients extracted and were adjusted
 for maximum overall effectiveness.


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 78:078-013
 A RAPID METHOD FOR ESTIMATING THE NITROGEN-SUPPLYING CAPABILITY OF A SOIL,
 Fox, R.H., and Piekielek, W.P.
 Pennsylvania State University, University Park, Department of Agronomy.
 Soil Science Society of America*Journal,  Vol.  42, No. 5,  p 751-753, September-
 October, 1978.  2 fig, 1 tab, 8 ref.

 Descriptors:  Nitrogen, Nutrient requirements,  Fertilization, Nutrients,  Crop
 response,  Corn (field), Correlation analysis,  Estimating,  Data collections.

 Nitrogen fertilizer recommendations in humid regions have  been primarily  based
 on crop N requirements without regard for the  variability  in the N-supplying
 capability of the soil.  The authors  found (reported in a  separate article)  that
 two previously proposed N availability indexes, 0.01M KaHC03 and boiling  0.01.M
 CaC12 extractable N,  were well correlated (r=0.77 and 0.86,  respectively;  P  <
 0.01 for both) with the capability of eight Pennsylvania  soils to supply  N to
 field grown corn, (Zea mays L.)   However, the  time and expense required for
 these analyses may preclude their routine use  by soil testing laboratories.   In
 seeking ways to shorten and simplify  the  analyses, it was  found that the  ultra-
 violet (UV)  absorption by the 0.01M NaHC03 soil extract at 260 nm was as  well
 correlated with the N-supplying capability of  the test soils (r=0.865 P <  0.01)
 as the best of the previously evaluated extractable N indexes.   This new method
 is as rapid, simple,  and inexpensive  as the methods currently used to measure
 availability of other essential nutrients in the soil.   It was also demonstrated
 how this method can be used to predict more accurately the fertilizer N needs
 for corn.


 78:07B-014
 GREENHOUSE EVALUATION OF RESIDUAL PHOSPHATE BY  FOUR PHOSPHORUS METHODS IN
 NEUTRAL AND CALCAREOUS SOILS,
 Bowman,  R.A.,  Olsen/  S.R.,  and Watanabe,  F.S.
 Colorado State University,  Fort Collins,  Department of Agronomy.
 Soil Science Society  of America Journal,  Vol.  42,  No.  3,- p 451-454,  May-June,
 1978.   3 fig,  3 tab,  32 ref,  2 equ.

 Descriptors:   Phosphorus, Chemical  analysis, Soil  chemical properties.  Calcareous
 soils,  Carriers,  Greenhouses.

 Four determinations of phosphorus—Olsen  P,  Colwell-P,  total exchangeable  P,  and
 reain-extractable P—were evaluated in terms of  total  plant  P uptake  in a  3-year
 continuous greenhouse study of 23 high P  calcareous  and neutral  soils.  All
 methods  were highly correlated with the total P  taken  up from the  soils by 5-8
 successive greenhouse crops.   The Olsen-P  procedure  extracted an average of
 nearly  50% of  the total plant  P while  the  colwell  procedure  extracted nearly
 80%.   Rasin-extractable P and  total exchangeable P values  approximated  the total
 plant P  uptake, and served as  good biological measures of  the total plant-
 available  P  in the soil.  No significant differences were  observed between the
 carrier  and  carrier-free  32P methods on the  23  tests soils.


 73:G7B-Q15
 AN  INEXPENSIVE PRECIPITATION GAUGE,
 Buchanan,  B.A., DeVelice, R.L. and  Urquhart, N.S.
 New  Mexico State  University, University Park, Department of Agronomy.
 Soil Science Society  of America Journal, Vol. 42,  No.  3, p 532-533, May-June,
 1978.  2 fig,  2 ref.

 Descriptors:   *Rain gages, *Design, *Equipment, Precipitation  (atmospheric),
 Rainfall,  Measurement,  Instrumentation, Gages, Arid lands,  Meteorology.

An  inexpensive, yet accurate, precipitation gauge was developed from readily
 available materials.  The gauge accurately estimated precipitation as measured
by a standard Weather Bureau gauge for  35  precipitation events in a one-year
period.  This  inexpensive gauge has been used successfully in the field for two
years.
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78:078-016
PESTICIDE TRANSPORT AND METABOLISM IN MODEL SYSTEMS,
Kaufman, D.D., Kearney, P.C., and Nash, R.G.
Pesticide Degradation Laboratory, Beltsville,  Maryland  20705.
In:  Symposium on Environmental Transport and Transformation of Pesticides,
October, 1976, Tbilis, USSR.  EPA-600/9-78-003, February, 1978, Athens,  Georgia,
p 61-72.  6 fig, 2 tab, 14 ref.

Descriptors:  Pesticides, Pesticide kinetics,  Pesticide residues,  Metabolism,
Assay, Soil microbiology, Microbial degradation, Sorption, Ecosystems,  Laboratory
tests.

Laboratory studies devoted to investigating the environmental fate of pesticides
have usually examined individual processes such as microbial metabolism, soil
leaching, surface and vapor phase photodecomposition, volatilization from plant
or soil surfaces, and plant uptake.  In the environment, however,  all of these
processes may be operative on the molecule, so that in each stage  of the pesticide
dissipation process, one or more processes may play a major role.   It has been
extremely difficult to study two or more of these processes under  controlled
conditions which will enable a clear understanding of the contribution of each.
Simplified model laboratory systems are now being developed which  enable simul-
taneous measurement of numerous factors affecting pesticide dissipation in the
environment.  This paper is a discussion of a few model laboratory systems.


78:076-017
RAPID DETERMINATION OF SOIL WATER CHARACTERISTIC BY THERMOCOUPLE PSYCHROMETRY,
Riggle, F.R., and Slack, D.C.
Minnesota University, St. Paul, Department of Agricultural Engineering.
Paper No. 78-2026, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978,  Logan, Utah, 24 p.  6 fig,  1 tab,
34 ref, 4 equ.

Descriptors:  Soil water, Moisture content, Moisture tension, Soil moisture,
Soil properties. Moisture availability, Soil tests, Drying, Irrigation,  Osmotic
pressure.

A procedure was developed for determination of the soil water characteristic
curve with thermocouple psychrometry.  Complete soil water characteristic curves
were obtained for a Nicollet clay loam, a Waukegan silt loam, and  a Hubbard
sandy loam within one week in ambient air conditions.  The curves  obtained by
the psychrometer method compared favorably with those obtained by  pressure
methods.


78:07B-018
THE SPECTROPHOTOMETRIC AND FLUOROMETRIC DETERMINATION OF ALUMINUM WITH 8-
HYDROXYGUINOLINE AND BUTYL ACETATE EXTRACTION,
Bloom P.R., Weaver, R.M., and McBride, M.B.
Minnesota University, St. Paul, Department of Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 5, p 713-716, September-
October, 1978.  2 .fig, 3 tab, 11 ref.

Descriptors:  Aluminum, Chemical analysis, Analysis, Spectrophotometry, Fluorometryi
Acidic soils, Solvent extractions, Organic matter.

A spectrophotometric method and a fluorometric method for the determination of Al
by the extraction of the Al-hydroxyquinolate complex with butyl acetate were
evaluated.  The Al complex was found to be very stable in butyl acetate.  The
spectrophotometric method was found to be useful for the analysis  of solutions
containing 50 ppb Al or greater.  The spectrophatometric response was linear up
to absorbance = 1.1.  The relative error in midrange was <2.5%.  The quantity
of Al determined in soil extracts was shown for some soils to be strongly dependent
on the time of contact with the complexing reagents before extraction with butyl
acetate.  This was attributed to the complexation of Al by organic matter in the
soil solutions.  The fluorometric method was found to have a detection limi/t of
about 0.3 ppb Al.  The fluorometric response was nearly linear in the most sensi-
tive range of the fluorometer but was less linear for higher Al concentrations.
The relative error was <8% except near the detection limit.  There was no


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interference with either method from Na(+), K(+), Mg(2+), Ca(2+), Sr(2+), Ba(2+),
Fe(2+), Fe(3+), F(-), PO4(3-), S04(2-), and S03(2-) at the levels found in most
soil extracts.


78:07B-019
ELECTRON PROBE MICROANALYTICAL STUDIES OF PHOSPHORUS DISTRIBUTION WITHIN SOIL
FABRIC,
Qureshi, R.H., Jenkins, D.A., and Davies, R.I.
Agricultural University, Lyallpur, Department of Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 5, p 698-703, September-
October, 1978.  4 fig, 13 ref.

Descriptors:  Phosphorus, Chemical analysis, Soil analysis. Soil tests. Analytical
techniques, Elements  (chemical), Root zone, Voids, Iron, Nutrients.

Electron probe microanalysis was used to follow the distribution of phosphorus
and associated elements within soil features to establish the composition of the
immediate root environment.  Various qualitative analytical modes of using the
instrument were described involving either specimen traverse or spectrometer
scanning with a static beam, line scanning, one-dimensional scanning, area
scanning, or successive rast counting.  By these means phosphorus was found to
occur variously as discrete grains of rare-earth phosphates, in preferential
association with iron in iron/manganese concretions, as concentrations within
undifferentiated soil matrix and ferrans at void surfaces, and to be associated
with calcium in a fresh root and possibly with iron rather than calcium, aluminum,
or potassium in an old root.


78:076-020
ELECTRON PROBE MICROANALYSIS OF CALCITE GRAINS CONTAINING PHOSPHORUS IN SOIL,
Qureshi, R.H., and Jenkins, D.A.
Agricultural University, Lyallpur, Department of Soil Science.
Soil Science Society of America Journal, Vol. 42, No. 5, p 703-705, September-
October, 1978.  4 fig, 11 ref.
(See 78:02K-045)


78:078-021
MEASUREMENT OF FURROW INFILTRATION RATES MADE EASY,
Miller, D.E., and Rasmussen, W.w.
Federal Research, Science and Education Administration, Prosser, Washington,
United States Department of Agriculture.
Soil Science Society of America Journal, Vol. 42, No. 5, p 838-839, September-
October, 1978.  3 fig, 1 tab, 9 ref.

Descriptors:  Infiltration rates,  Infiltration, Furrow irrigation, Infiltrometers,
Computer programs, Measurement.

An irrigation system was developed for infiltration studies that utilized overflow
controls to maintain nearly constant inflow into irrigation furrows.  Furrow out-
flow was measured with HS flumes equipped with water-level recorders.  Data were
easily and rapidly converted to infiltration rates and cumulative infiltration
by a computer.


78:078-022
GRAVIMETRIC VS. VOLUMETRIC DETERMINATION OF WATER STORAGE IN VERTICALLY UNSTABLE
TILLAGE LAYERS,
Steinhardt, R.                   ,„•,„      ,.„.,:,,.,.
Institute of Soils and Water, Agricultural Research Organization, The Volcani
Center, Bet Dagan, Israel, Division of Soil Physics.
Soil Science Society of America Journal, Vol. 42, No. 5, p 836-837, September-
October, 1978.  1 tab, 14 ref, 5 equ.

Descriptors:  Water storage, Soil water, Moisture content, Soil compaction,
Frost heaving, Drainage, Irrigation, Gravimetric analysis, Volumetric analysis,
Methodology.
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 Methods  of determining water  storage  (W)  in  a  tillage  layer of  changing height
 were analyzed to  compare the  effects  of  agrotechnical  management on W.  It
 was  shown that changes in W may be  evaluated from  a  single estimate of the  solid
 mass per unit area at a  state of  reference and periodic observations of the
 gravimetric water content of  the  tillage layer, which  is  equivalent to the  usual
 procedure of stable soils.


 78:07B-023
 DIRECT IN-FIELD MEASUREMENT OP NITROUS OXIDE FLUX  FROM SOILS,
 Ryden, J.C., Lund,  L.J.,  and  Focht, D.D.
 California University, Riverside, Department of Soil and  Environmental Science.
 Soil Science Society of  America Journal,  Vol.  42,  No.  5,  p 731-737, September-
 October,  1978.  2 fig, 5  tab,  29  ref.

 Descriptors:  Denitrification, Nitrates,  Gas chromatography, Measurement,
 Fertilization,  Ozone, Methodology,  Data  collections.

 A method was developed whereby nitrous oxide N20 effusing from  a soil surface
 could be contained and selectively  trapped for subsequent analysis.  The methodo-
 logy proposed provides a  direct measurement  of N20 flux which is integrated over
 the  sampling period used.   The methodology is  sufficiently simple that it em-
 bodies a monitoring capability which  can  be  used to measure N20 evolution in
 on-going agricultural practice.   The  method  may also provide a  basis for the
 direct measurement of total N loss  as a  result of  denitrification, if the further
 reduction of N20  to N2 can  be  inhibited.


 78:07B-024
 FIELD TESTING OF  SEVERAL  NITROGEN AVAILABILITY INDEXES,
 Fox,  R.H.,  and Piekielek, W.P.
 Pennsylvania State  University, University Park, Department of Agronomy.
 Soil Science Society of America Journal,  Vol.  42,  No.  5, p 747-750, September-
 October,  1978.  2 fig, 3  tab,  9 ref.

 Descriptors:   Nitrogen, Fertilization, Soil  tests, Crop production, Chemical
 analysis,  Crop response,  Corn  (field), Laboratory  tests.

 Eight N  availability indexes were correlated with  the  capability of eight
 Pennsylvania soils  to supply N to field-grown  corn (Zea mays L.) in 1976 and 1977.
 Boiling  O.OlM CaC12  and 0.01M NaHC03-extractable N were both significantly correlated
 at the 1%  level (r  = 0.86 and  0.77, respectively) with the N-supplying capability
 of the soils from the combined 1976 and  1977 experiments.  Autoclave-extractable
 NH4-N and total soil N were significantly correlated with the soil supplying
 capability at the 5%  confidence level (r=0.70  and  0.68, respectively).  Walkley-
 Black soil organic  matter, Soil NO3(-), and  H2S04-extractable and KCl-extractable
 N were not significantly  correlated with  N availability in the  field.   Though four
 of the indexes were well  correlated with  the N availability in  the soil, time and
 expense  necessary for these analyses may preclude their being used routinely by
 soil  testing laboratories.


 78:078-025
 REMOTE SENSING OF WATER LEVELS IN SMALL DIAMETER WELLS,
 Lovell, A.D., Ellis, J.W., Bruce, R.R., and  Thomas, A.W.
 United States Department  of Agriculture, Science and Education Administration,
Watkinsville, Georgia  30677.
Agricultural Engineering, Vol. 59, No. 10, p 44-45, October,  1978.   4  fig.

 Descriptors:  Water  level recorders, Water level fluctuations, Water levels, Remote
 sensing, Pressure head,  Piezometers.

A remote sensing  device was developed that measures water level changes in
potentiometer resistance.  This device is capable to follow water levels in small-
diameter piezometer  tubes installed at depth ranging from 125 cm to 305 cm and can
measure the water level to within about 5 mm.
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 78:073-026
 AUTOMATED SAMPLING ANALYSIS OF RURAL NONPOINT SOURCE WATER QUALITY,
 Humenik, F.J., Bliven, L.F.,  Koehler, F.A.,  and Overcash,  M.R.
 North Carolina State University^ Raleigh,  Department of Biological and
 Agricultural Engineering.
 Paper No. 78-2509, Presented at the 1978 Winter Meeting of the  American Society
 of Agricultural Engineers,  December 18-20,  1978, Palmer House Hotel,  Chicago,
 Illinois, 10 p.  5 fig, 4  tab, 18 ref,  2 equ.

 Descriptors:  Water quality,  Water pollution,  Water sampling, Water pollution
 sources, Automation, Water  yield, Ion transport, Base flow,  Flow duration.

 Automated sampling was employed to assess  constituent (COD,  TOC,  TP,  TKN, NO3-N,
 and Cl)  yields and concentrations from two Piedmont sites  in Virginia and two
 poorly-drained Coastal Plain  sites in North  Carolina within  the Chowan River
 watershed.   These data were analyzed to provide a mechanistic interpretation
 of subbasin processes.  Characteristic  Piedmont and Coastal  Plain seasonal water
 yield cycles which have winter maximums and  summer  minimums  were  related to
 regional potential water yields (rainfall minus evapotranspiration).   Large
 water yield variations for  subbasins within  each region, however,  were attributed
 by physical differences between subbasins.   Greater water  yield from  the
 agricultural Piedmont site  than from the forested Piedmont site reflected in-
 creased  cleared land plus greater channelization both on the basis of channel
 density  and channel gradient  at the agricultural site.  Elevated  baseflow,
 probably due to stream channelization,  was the dominant factor  contributing
 to water yield differences  between two  Coastal Plain subbasins.   Surface flow
 COD,  TOC,  TP,  TKN and N03-N concentrations were usually greater than  baseflow
 concentrations,  but at the  unchannelized Coastal Plain site  the opposite case
 prevailed and at all sites  surface flow Cl concentrations  were  less than base-
 flow  concentrations.   The seasonal concentration cycle displayed  a summer
 maximum  and winter minimum  and thus it  was out of phase with the water yield
 cycle.


 78:078-027
 MEASURING FLUMES  OF SIMPLIFIED CONSTRUCTION,
 Replogle, J.A.,  and Clemmens,  A.J.
 United States  Water Conservation  Laboratory, Science  and Education Administration,
 Phoenix,  Arizona,  Department of Agriculture.
 Paper No. 78-2506,  Presented at the 1978 Winter Meeting of the  American  Society of
 Agricultural Engineers,  December  18-20,  1978,  Palmer  House Hotel,  Chicago,
 Illinois, 13 p.   10  fig, 3  tab, 15  ref.

 Descriptors:   Flumes,  Measurement,  Mathematical models, Flow measurement,
 Irrigation  canals,  Critical flow,  Construction costs.

 Mathematical modeling  was applied  to optimize  error control  and construction
 simplicity  for the  selection of a  family of long-throated flumes, resembling
 broad-crested weirs with a sloping  approach ramp, for  use in trapezoidal irrigation
 canals.  Alternate  shapes and  sizes were proposed for unlined canals with
 extensions  to  sizes  and  shapes for  limited application  to watershed work.


 78:076-028
 SAMPLING AND CHEMICAL  INTERPRETATION OF PRECIPITATION FOR MASS BALANCE STUDIES,
 Lewis, W.M., and Grant, M.C.
 Colorado University, Boulder,  Department of Environmental Population and Organismic
Biology.
Water Resources Research, Vol. 14, No.  6, p 1098-1104, December, 1978.  2 fig,
 1 tab, 40 ref.

Descriptors:  Precipitation (atmospheric),  Chemistry of precipitation, Sampling,
Chemical analysis, Rainfall, Rain gages, Design, Data collections.


From an analytical viewpoint,  total dry and wet precipitation consists of three
fractions:   (.1)  dissolved materials in aqueous precipitation,  (2) the water-
soluble component of dry precipitation, and (3) the water-insoluble component of
either wet or dry precipitation.  Methods of precipitation  collection and pro-
cessing greatly affect the separation of these components.   A literature survey

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showed that fraction 3 has typically been ignored and that samplers currently in
use lead to a highly variable mixture of the three fractions.  A literature survey
also showed that most collectors currently in use are of insufficient size to col-
lect samples large enough to support broad-spectrum analysis on a weekly basis.  The
minimum satisfactory size of collectors was computed from (1) average rain chemistry,
(2)  sensitivity of standard chemical tests for chemical species of biological in-
terest, and (3)  volume required for each analysis.  The computations showed that
collectors should have an area of at last 1200 sq cm in regions of average chemistry
and as much as 8300 sq cm in cold climates with minimal aqueous precipitation.  A
design was given for a collector which combines large size with other desirable
features.


78:07B-029
SERIOUS INTERFERENCES IN THE DETERMINATION OF TRACE METALS IN SOILS BE FLAME AND
FLAMELESS ATOMIC ABSORPTION SPECTROMETRY,
Mubarak, A., Hageman, L., Howald, R.A., and Woodriff, R.
Montana College of Mineral Science and Technology, Butte, Department of Chemistry.
Soil Science Society of America Journal, Vol. 42, No. 6, p 889-891, November-December,
1978.  5 tab,  14 ref.
(See 78:02K-059)


78:078-030
OXYGEN FLUX MEASUREMENT IN UNSATURATED SOILS,
Rankin, J.M.,  and Sumner, M.E.
Malcomess Ltd., Isando, South Africa, Department of Agronomy.
Soil Science Society of America Journal, Vol. 42, No. 6, p 869-873, November-
December, 1978.  3 fig, 3 tab, 12 ref.

Descriptors:  Oxygen, Soil gases, Diffusion, Aeration, Deaeration, Oxidation-reduc-
tion potential, Electrodes, Measurement, Instrumentation, Electrical resistance.

Because in unsaturated soil systems the plateau of the current-voltage curve is not
well developed or is absent, 02 reduction at the platinum microelectrode is not
diffusion controlled and consequently measured current depends continuously on
applied potential.  To overcome this difficulty an 02 flux meter was designed which
carefully controls and measures the applied potential and enables the effective
potential at the electrode to be measured precisely.  The instrument, which has
facilities for measuring soil electrical resistance, electrode redox potential, and
02 reduction current was fully described together with a circuit diagram.  Because
the surface oxide condition of the microelectrode is crucial to reproducible results,
electrode pretreatment involving gentle abrasion in wet fine sand is necessary to
standardize conditions prior to measurement.  The results showed that the instrument
is suitable for measuring 02 flux in unsaturated systems, and that measured current
was closely related to soil airspace.


78:07B-031
DETERMINATION OF THE APPARENT DISPERSION COEFFICIENT OF SOLUTES IN UNSATURATED SOIL,
Paetzold, R.F., and Scott, H.D.                  S
United States Department of Agriculture, Soil Conservation Service, National Soil
Survey Laboratory, Lincoln, Nebraska  68508.
Soil Science Society of America Journal, Vol. 42, No. 6, p 874-877, November-December,
1978.  3 fig,  1 tab, 14 ref, 16 equ,
(See 78:02K-062)


78:078-032
TO MARK SAMPLING EVENTS ON A RUNOFF HYDROGRAPH,
Johnson, A.T.,  Kort, R., and Ayars, J.E.
Maryland University, College Park, Department of Agricultural Engineering.
Agricultural Engineering, Vol. 59, No. 9, p 22-23, September, 1978.  2 fig.

Descriptors:  Runoff, Hydrographs, Intermittent streams, Instrumentation, Stream
gages.

This article described how a Stevens Type F Water Stage Recorder can be modified
to make it more practical for runoff studies and to monitor streams where flow is
intermittent.


                                       268

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78:078-033
THE PREDICTION OF MEAN MONTHLY SOIL TEMPERATURE FROM MEAN MONTHLY AIR
TEMPERATURE,
Toy, T.J., Kuhaida, A.J., and Mwnson, B.E.
Denver University, Denver, Colorado, Department of Geography,
Soil Science, Vol. 126, No. 3, p 181-189, September, 1978.  4 fig, 3 tab, 13 ref,
5 equ.

Descriptors:  Soil temperature, Air temperature, Climatic data, Estimating equa-
tions.

Though soil temperature is important to a variety of earth science subdisciplines,
data are collected at few locations.  This report presented simple, linear models
for estimating mean annual, seasonal, and monthly soil temperatures with reasonable
accuracy, using only air temperature data.  A general equation based on all months
and all sample stations taken together, seasonal equations, and equations for
individual stations were provided.  These models can be used to estimate soil
temperature from air temperature data collected by the National Weather Service
at stations throughout the United States.


78:07B-034
SOIL MOISTURE DETERMINATION USING MICROWAVE RADIATION,
Hankin, L., and Sawhney, B.L.
The Connecticut Agricultural Experiment Station, Box 1106, New Haven, Connecticut
06504.
Soil Science, Vol. 126, No. 5, p 313-315, November, 1978.  1 fig, 4 tab, 5 ref.

Descriptors:  Moisture content, Soil moisture, Gravimetric analysis, Laboratory
tests, Laboratory equipment, Sampling, Microwaves, Moisture.

The advantages of microwave treatment over conventional heating are simplicity
of operation and speed, especially in experimental studies where changes in
design are necessary as experiment proceeds.  A simplified method was reported
in this article for soil moisture determination by microwave ove  using ordinary
filter paper folded into cups for holding the sample.  Two soils, a heavy-
textured and a light-textured soil; and two fine clays, montmorillonite and
kaolinite were used in this study.  By the method described in this paper, the
optimum heating time was found to be 6 minutes and about a 10 g sample appeared
to be most convenient for moisture determination by the method described in this
article.


78:078-035
MODIFICATIONS TO A SOIL OXYGEN DIFFUSION RATEMETER,
Bornstein, J., and McGuirk, M.
Maine University, Orono, Northeast Plant, Soil, and Water Laboratory.
Soil Science, Vol. 126, No. 5, p 280-284, November, 1978.  1 fig, 5 ref, 5 equ.

Descriptors:  Aeration, Soil gases, Oxygen, Laboratory equipment, Diffusion,
Electrical resistance, Laboratory tests, Calibrations.

Recent efforts to relate soil aeration to crop production rely in part on soil
oxygen diffusion rate (ODR) measurements.  The platinum microslectrode method is
often used to measure the soil ODR.  The electrode current is easily interpreted
when the soil is saturated with water.  When the soil is not saturated, the
interpretation of the electrode current depends on the effective potential applied
to the microelectrode.  The effective potential cannot be measured directly, but
is calculated from several other measured quantities.  The equation for obtaining
the effective potential is given for two types of ODR measurement systems.  The
second type is commercially available and offers several advantages, but has
limited accuracy at low ODRs.  Two modifications to the commerical system were
described, both of which greatly increase the accuracy of the system.


78:078-036
IN SITU HYDRAULIC CONDUCTIVITY OF A FRAGIPAN SOIL IN THE SOUTHERN COASTAL PLAINS,
Prasad, K.G., and Perkins, H.F.
Georgia University, Athens.
Soil Science, Vol. 126, No. 5, p 263-268, November, 1978.  3 fig, 2 tab, 21 ref.

                                     269

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Descriptors:  Hydraulic conductivity, Hydrologic properties, Soil horizons,
Coastal plains, Moisture availability. Soil water. Perched water.

More than 250,000 ha of soils having a fragipan or fragic properties occur in
the Southern Coastal Plains Soil Province.  These soils have moderate to severe
land use restrictions, partially due to perched water, slow permeability, and
restricted root growth.  The Cowarts soil (Fragic Paleudults; fine-loamy,
siliceous, thermic family), which is developed from marine sediments, was se-
lected to determine in situ hydraulic conductivities and related hydrological
properties.  The moderately well-expressed fragipan has higher bulk density,
less pore space, smaller pores, less available water, and lower hydraulic
conductivity values than horizons above or below the pan.  With an increase in
hydraulic head, an increase in hydraulic conductivity was less in the fragipan
than in associated horizons.
                                     270

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                               SECTION XXXIII


                               RESOURCES DATA

             EVALUATION, PROCESSING AND PUBLICATION  (GROUP 07C)


78:07C-001
ESTIMATION OF AGRICULTURAL NONPOINT LOADS TO THE WAKARUSA RIVER BASIN USING THE
"NONPOINT CALCULATOR",
Davis, M.J., and Nebgen, J.W.
Midwest Research Institute, Kansas City, Missouri.
Proceedings of the 1978 Cornell Agricultural Waste Management  Conference, p 525-
550.  1 fig, 14 tab, 2 ref, 7 equ.
(See 78:05G-063)
                                     271

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                                SECTION XXXIV


                              ENGINEERING WORKS

                           STRUCTURES (GROUP 08A)


78:08A-001
IRRIGATION PIPE REPAIR CUTS COSTS,
Larsen, R., Associate Editor.
Irrigation Age Magazine.
Irrigation Age, Vol. 12, No. 7, p 6, April, 1978.  1 fig.

Descriptors:  Pipelines, Pipes, Repairing, Cost comparisons, Colorado, Equipment,
Instrumentation, Maintenance, Engineering structures.

The experience of a Colorado farmer who designed a repair operation for damaged
aluminum irrigation pipes was discussed.  Repairing damaged pipes has proved to
be considerably cost-effective in comparison to the costs for new pipes.


78:08A-002
TRENCHLESS DRAINAGE,
Reeve, R.C.
Advanced Drainage Systems, Incorporated, Columbus, Ohio.
Paper No. 78-2042, Presented at the 1978 Summer Meeting of the American Society
of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 9 p.  9 fig.

Descriptors:  Subsurface drainage, Subsurface drains, Drainage practices,
Trenches, Maintenance costs, Installation, Groundwater, Drainage.

Following the development of corrugated plastic tubing and automatic laser
grade control in the 1960s, a dramatic move to "trenchless" drainage has taken
place in the 1970s.  Low maintenance costs and high installation rates  (up to
50,000 ft per day) has given the competitive edge that is shifting the industry
from trench to "trenchless" drainage.


78:08A-003
SEDIMENT TRAPS IN CHANNELS—DESIGN PROCEDURES AND PERFORMANCE,
Konwinski, G.R.
Soil Conservation Service, East Lansing, Michigan.
Paper No. 78-2561, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 6 p.  2 fig.
(See 78:02J-028)


78:08A-004
DEVELOPMENT AND APPLICATION OF SEDIMENT BASINS IN MARYLAND,
Boysen, S.M.
Soil Conservation Service, College Park, Maryland, United States Department of
Agriculture.
Paper No. 78-2562, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 13 p.  2 fig, 9 ref, 1 append.

Descriptors:  Sediment control. Trap efficiency, Soil erosion, Design criteria.
Design standards. Specifications, Sediment yield, Detention reservoirs, Skimming.

Sediment basins are an important part of the sediment control program in Maryland.
Criteria were presented for estimating trap efficiency of basins.  Experiences
and results of field observations were presented.  Standards and specifications
prepared by the Soil Conservation Service for sediment basins in Maryland were
attached.
                                     272

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                                    SECTION XXXV


                                  ENGINEERING WORKS

                                HYDRAULICS (GROUP 08B)


78:08B-001
APPLICABILITY OF KINEMATIC AND DIFFUSION MODELS,
Ponce, V.M., Li, R.M., and Simons, D.B.
Colorado State University, Fort Collins, Department of Civil Engineering.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY3, Proceedings Paper 13635, p 353-360, March, 1978.  4 fig, 1 tab, 5 ref,
3 append.

Descriptors:  *Diffusion, *Model studies, *0pen channels, *Kinematic models,
Dynamics, River beds, Waves (water), Saint Venant equation, Wave period,
Mathematical studies.

The applicability of the kinematic and diffusion models of open channel flow
was assessed by comparing the propagation characteristics of sinusoidal •
perturbations to the steady uniform flow for the kinematic, diffusion, and
dynamic models (the dynamic model is that based on the complete Saint Venant
equations).  The comparison allowed the determination of inequality criteria
that need to be satisfied if the kinematic or diffusion models are to simulate
the physical phenomena within a prescribed accuracy.  It was shown that bed
slope and wave period (akin to wave duration in waves of shape other than
sinusoidal) are the important physical characteristics in determining the
applicability of the approximate models.  Larger bed slopes or long wave periods,
or both, will satisfy the inequality criteria.  In practice, larger bed slopes
are those of overland flow, and long wave periods are those corresponding to
slow-rising flood waves.


78:08B-002
DIRECT SOLUTION TO PROBLEMS OF OPEN CHANNEL TRANSITIONS,
Vittal, N.
Roorkee University, India, Department of Civil Engineering.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY11, p 1485-1494, November, 1978.  6 fig, 1 ref, 17 equ, 2 append.

Descriptors:  Transition flow, Open channel flow, Subcrltical flow, Critical flow,
Open channels, Hydraulic design, Culverts, Aqueducts, Graphical methods, Flow
characteristics.

The existing methods of solving open channel transitions involve trial-and-error
solution of higher degree equations.  In this paper, a method was proposed which
presents unique dimensionless discharge-depth relationships for exponential,
trapezoidal, and circular channels that facilitate direct solutions even to com-
plex problems of contracting open channel transitions.  The steps enumerated in
the examples demonstrated the simplicity of the method.  It was recommended that
enlarged design charts of the proposed graphical relations are used in actual
design for accuracy.  Alternatively, design tables prepared from given equations
may also be used.


78:088-003
HYDRODYNAMIC PERFORMANCE OF PIPE UNDERDRAINS,
Mevorach, J., and Zanker, K.
Technion-Israel Institute of Technology, Haifa, Department of Hydrodynamics and
Hydraulic Engineering.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 104, No. IR1, Proceedings Paper 13636, p 127-142, March, 1978.
15 fig, 4 ref, 2 append.
                                     273

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 Descriptors:   *Valves,  *Hydraulic valves,  *Drainage, Channels, Flow, Drains,
 Pipes,  Sediments, Groundwater, Flexible-flap drain valves.

 Theoretical analysis and  laboratory investigations of  flexible-flap drain valve
 in high-velocity open channel flow were presented.  Main hydrodynamic
 characteristics of  the  valve are:   (1) Radial diffuser action, which prevents
 the valve  from opening  at low pressures; and (2) uplift forces, caused by high-
 velocity flow  in the channel, helping the  valve to open.  The most severe con-
 dition  for the valve operation is when there is little or no flow in the
 channel, but there  is still high groundwater table around the channel.  Flap-
 valves  are found suitable for use in high-velocity flows, provided that the
 ratio,  R sub 2/R sub 1, between the circular flap and the valve opening is kept
 as low  as  compatible with engineering considerations.


 78:08B-004
 SIMULATED  FLOW RATE REQUIREMENTS FOR SOME  FLUSHING EMITTERS,
 Solomon, K., and Bezdek,  J.C.
 Utah State University,  Logan, Department of Mathematics.
 Paper No.  78-2016,  Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 18 p.  3 fig, 5 tab,
 8 ref,  1 equ.

 Descriptors:   Flow  rates,  Simulation analysis, Hydraulic models, Irrigation,
 Lateral conveyance  structures, Model studies, Irrigation systems, Hydraulic
 properties, Water pressure.

 A steady state simulation model was used to study the hydraulic behavior of
 trickle irrigation  laterals and manifolds  employing automatic flushing emitters.
 The influence  of emitter  characteristics and design values such as emitter
 operating pressure, flow  rate, spacing, and lateral length were considered.


 78:088-005
 TRICKLE IRRIGATION  TUBING  HYDRAULICS,
 Watters, G.Z., and  Keller, J.
 Utah State University, Logan, Department of Civil and Environmental Engineering.
 Paper No.  78-2015,  Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 18 p.  16 fig, 2 tab,
 12 ref, 14 equ.

 Descriptors:   Pipe  flow, Hydraulic properties,  Irrigation systems, Head loss,
 Darcy-Weisbach equation, Moody resistance  diagrams, Pipelines, Hazen-Williams
 equation. Analytical techniques, Graphical methods.

 Laboratory experiments show that the Darcy-Weisbach equation for hydraulically
 smooth pipes should be used to compute friction losses in PVC pipe and plastic
 tubing.  Simple formulas are presented to  accomplish this.  Graphs to find
 equivalent lengths  for emitter connection  losses are given.   Techniques for
 calculating head losses in multiple-outlet lines are presented.


 78:088-006
 PRESSURE LOSSES ACROSS TRICKLE IRRIGATION FITTINGS AND EMITTERS,
 Howell, T.A.,  and Barinas, F.A.
 Texas A & M University, College Station, Department of Agricultural Engineering.
 Paper No. 78-2014, Presented at the 1978 Summer Meeting of the American Society
 of Agricultural Engineers, June 27-30, 1978, Logan, Utah, 12 p.  16 fig, 1 tab,
 7 ref, 10 equ.

 Descriptors:    Energy loss, Energy gradient. Irrigation design, Flow rates,
 Lateral conveyance structures. Pipelines, Pressure conduits, Irrigation systems,
Water pressure, Hazen-Williams equation.

 Pressure losses across on-line trickle emitters were measured.  The energy losses
 as expressed by the equivalent length of pipe were described by a power function.
 The empirical  coefficients were related to the emitter characteristics of pro-
 trusion depth  and area.  Lateral design procedures and examples are presented.
Pressure losses across PVC and PE barbed fittings were measured.


                                     274

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78:088-007
SIZE DETERMINATION OF PARTLY FULL CONDUITS,
Mussalli, Y.G.
Stone and Webster Engineering Corporation, Boston, MA. Hydraulic Division.
Journal of Hydraulic Division, American Society of Civil Engineers, Vol. 104,
No. HY7, Proceedings Paper 13862, p 959-974, July, 1978.  13 fig, 2 tab, 9 ref.

Descriptors:  *Air-water interfaces, *Flow control, *Free surfaces, *Air-water
interactions, Surface runoff, vibrations, Hydraulics, Mathematical studies,
Equations, Water tunnels.

The transition from partly full to full pipe (sealing) is accompanied by
vibrations of the structure and surging of the flow.  The experimental study was
done in a 4-in (100-mm) square conduit with three different circular bends, with
various deflectors, and with various concentrations of air.  Sealing depends on
the Froude number of the flow.  To maintain partly full flow, more space is
needed above the water-flow area with an increase of Froude number.  With short-
tube control, the ratio of the radius of curvature along the center line to the
bend diameter and the deflector thickness at the crown of the bend determine the
water-flow area in the horizontal conduit.  Ventilation of the horizontal con-
duit delays sealing, while aeration of the water flow hastens sealing.  With
weir control, waves on the flow surface hasten sealing, and highly aerated flow
delays sealing.  Ratios of radius of curvature to the bend diameter larger than
2.0 were recommended since they generate fewer waves.


78:08B-008
VARIED FLOW FUNCTIONS FOR CIRCULAR CHANNELS,
Nalluri, C., and Tomlinson, J.H.
Newcastle-upon-Tyne., England, Department of Civil Engineering.
Journal of Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY7, Proceedings Paper 13889, p 983-1000, July, 1978.  2 fig, 4 tab, 11 ref.

Descriptors:  *Backwater, *Channels, *Flow, Conduits, Flow profiles. Gradually
varied flow, Open channels, Pipes, Hydraulics,  Backwater profiles.

Hydraulic engineers often are required to compute backwater curves, and the
existing methods cannot be applied accurately to closed conduits as the flow
approaches the crown.  This paper reviewed the Keifer and Chu method which uses
the dimensionless parameter Q/QCAP.  A new approach was developed to compute
backwater curves in circular channels in which the factor Q/QCAP is removed so
that errors are not introduced by having to interpolate these values.  This new
method is applicable for all possible bed slope conditions (horizontal, adverse),
which is a distinct advantage over the other existing techniques.  Semigraphical
methods also were suggested to increase the speed of computation of backwater
curves.


78:088-009
AMERICAN DEVELOPMENTS IN HYDRAULIC MEASUREMENT,
Ripken, J.F.
Minnesota University, Minneapolis, St. Anthony Falls Hydraulic Laboratory.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY6, Proceedings Paper 13821, p 857-868, June, 1978.  1 ref, 1 append.

Descriptors:  *Measurement, "Instrumentation, "Discharge (water), *Flow
measurement, "History, Wiers, Electronic equipment, Orifices, Hydrometry, Flumes.

A historical summary is presented of American contributions to hydraulic mea-
surement of streamflow for the period 1776-1976.  The development and interrelation
of conduit flow measuring devices, together with open channel measuring devices,
was included in this update of previous historical summaries.  The narrative
style and historical sequencing is a useful complement to the more specific
"Bibliography on Discharge Measurement Techniques."


78:088-010
HYDRAULIC FRICTION LOSS IN SMALL DIAMETER PLASTIC PIPELINES,
Hughes, T.C., and Jeppson, R.W.              ..,,,.              .
Utah State University, Logan, Department of Civil and Environmental Engineering.

                                        275

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Water Resources Bulletin, Vol. 14, No. 5, p 1159-1166, October, 1978.   1 fig,
1 tab, 2 ref, 4 equ,  1 append.

Descriptors:  Plastic pipe, Hydraulic conduits, Pipe flow, Design, Hazen-
Williams equation, Darcy-Weisbach equation, Reynolds number, Flow friction,
Water supply. Moody resistance diagrams.

Field measured friction losses in three one-mile sections of small diameter pvc
pipe which have been in service for ten years is reported.  Hazen-Williams and
Darcy-Weisbach equations were examined to provide a framework for comparing Hazen-
Williams coefficients recommended by pipe manufacturers to those obtained by the
field measurements.  It was concluded that the Hazen-Williams coefficient of 150
recommended by most pvc pipe manufacturers is too high for the diameter-velocity
combinations encountered in rural dead-end small diameter lines.  The measured
coefficients averaged 133 which is close to that predicted by superimposing
Hazen-Williams coefficients on the Moody diagram from which the friction factor
for the Darcy-Weisbach equation is obtained.


78:08B-011
KALMAN FILTER IN OPEN CHANNEL FLOW ESTIMATION,
Chiu, C.L., and Isu, E.O.
Pittsburgh University, Pennsylvania, Department of Civil Engineering.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY8, Proceedings Paper 13946, p 1137-1152, August, 1978.  9 fig, 19 ref.

Descriptors:  *0pen channels, *Model studies, *Open channel flow, *Kalman filter.
Mannings equation, Estimating, Resistence coefficients, Manning formula,
Open channel hydraulics, Hydraulics.


In computing water surface profiles in open channels, uncertainties often arise
in selection of resistance coefficients, such as Manning's n.  In this paper
the Kalman filtering approach was developed to deal with such uncertainties.
This approach combined a mathematical system model and an observation model.
The former consists of (1) stochastic nonlinear differential equation governing
the steady one-dimensional open channel flow; and  (2) one of three possible
stochastic differential equations expressing Manning's n  (constant, function of
the location of channel cross section, or function of both the location and
the water depth).  The observation model simply shows the observed water depth
as the sum of "true water depth" and  "error".  The estimation technique was
tested for its accuracy in generating estimates of water depth and Manning's n
at several different schemes of sampling or measuring water depths.  Results with
Kalman filtering were compared with two parallel methods normally used today.


78:088-012
AIR-WATER FLOW IN COARSE GRANULAR MEDIA,
Hannoura, A.A., and McCorquodale, J.A.
Windsor University, Ontario, Department of Civil Engineering.
Journal of the Hydraulic Division, American Society of Civil Engineers, Vol. 104,
No. HY7, Proceedings Paper 13888, p 1001-1010, July, 1978.  5 fig, 1 tab, 15 ref.

Descriptors:  *Breakwaters, *Darcys law, *Granules, *Porous media, *Coastal
engineering, Entrainment, Hydraulic conductivity, Waves  (water). Hydraulics,
Air-water interfaces.

Air may be entrained in the flow in porous shore structure under wave action.
Three conceptual models for two-phase flow in ducts were  adapted to describe
flow in coarse granular media.  These are the homogeneous bubbly drift-flux,
and slug drift-flux models.  An experimental study was undertaken to check
the three models against air-water flow in three coarse granular porous media.
The best model was chosen based on its agreement with the experimental head
drop results.  On this basis,  the slug flow drift-flux model was recommended to
calculate the effect of entrained air on the hydraulic conductivity for co-
current and counter current flows.
                                      276

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78:088-013
DISPERSION IN RIVERS AS RELATED TO STORAGE ZONES,
Sabol, G.V., and Nordin, C.P.
New Mexico State University, University Park, Department of Civil Engineering.
Journal of the Hydraulics Division, American Society of Civil Engineers,. Vol.
104, No. HY5, Proceedings Paper 13758, p 695-708, May, 1978.  4 fig, 3 tab,
26 ref, 2 append.

Descriptors:  *Dispersion, *Rivers, *Reservoirs, *Model studies, Mathematical
models, Suspended solids, Markov processes, Theoretical analysis, Sedimentation,
River flow.

Longitudinal dispersion was considered as a simple stochastic process in which
a particle travels random time periods at constant velocity, with travel
period separated by random time periods during which the particle is trapped
in storage zones.  The average number per unit time of entries into storage
was considered to be a function of time.  The resulting model was a nonhomo-
geneous compound Poisson process defined by three parameters.  Methods for
estimating the parameters were given, and predicted concentration distributions
were shown to agree reasonably well with observed field data.
                                     277

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                                SECTION XXXVI


                              ENGINEERING WORKS

                       HYDRAULIC MACHINERY  (GROUP 08C)


78:08C-001
COLORADO PUMP TESTS SHOW HOW TO MAKE BIG DOLLAR SAVINGS,
Ross, R.
Irrigation Age, Vol. 12, No. 6, p 8-9+, March, 1978.  2 fig.

Descriptors:  ^Irrigation operation and maintenance, *Pumping, Energy, Costs,
Efficiencies, Electric power costs, Electric power rates, Conservation.

A recent pump testing program in Colorado has demonstrated a huge potential for
electrical energy savings in that state if the average efficiency of irrigation
pumps could be upgraded.  Program researchers have maintained that efficiencies
of 65% are readily achievable by proper pump selection and care, and significant
number of systems tested were found to perform at this level.  However, average
efficiencies in approximately 600 systems tested were only about 45% for open
discharge systems and 56-60% for sprinklers.  Various remedial measures can be
taken to improve pump efficiency, such as adjustment of the impeller, replace-
ment of worn parts, proper sizing, improved well construction, and modification
of operating procedures.  Unfortunately, present electrical rate structures
frequently discourage such measures.  Net savings in a declining block rate
structure, for example, may be to low to offset the capital cost of upgrading
the irrigation system, thus the farmer's decision is not to repair the pump.
If irrigation power rates were reformulated so that cost to the farmer were
closer to the actual average cost per kwh, then the economic incentive to con-
serve energy would be enhanced.
                                     278

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                               SECTION XXXVII



                              ENGINEERING WORKS

                   ROCK MECHANICS AND GEOLOGY  (GROUP 08E)


78:08E-001
DESIGN UNDER STOCHASTIC GROUNDWATER FLUCTUATION,
Bogardi, I., and Duckstein, L.
Arizona University, Tucson, Department of Hydrology and Water Resources.
Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 104,
No. HY1, Proceedings Paper 13499, p 59-74, January, 1978.  4 fig, 3 tab, 22 ref,
4 append.

Descriptors:  *Aquifers, *Groundwater, *Concrete structures, *Stochastic processes,
*Failure (mechanics), "Hungary, *Danube River, *Budapest (Hungary), Bivariate
analysis, Decision theory.

A foundation is to be protected against the harmful effects of sulfur groundwater,
whose piezometric head fluctuates in a random manner.  The stochastic process
forms a partial duration series, where the jth event is defined by the maximum
exceedance above the foundation floor, the duration and interarrival time until
the (j + l)st event.  To protect the structure against possible damage by high
levels of groundwater with substantial sulfate concentration, it is possible to
make four decisions, corresponding to waterproofing or using special sulfate
resistant concrete or both, or providing no protection.  The annual cost and
expected loss associated with each of these four decisions were calculated with
the help of explicit expressions.  Sensitivity of the decision to sample, model,
and economic uncertainty was analyzed as well as the possibility of using a
Bayesian approach to account for sample uncertainty.
                                     279

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                              SECTION XXXVIII


                              ENGINEERING WORKS

                            MATERIALS  (GROUP 08G)


78:080-001
ASPHALT-CRUMB RUBBER WATERPROOFING MEMBRANE,
Frobel, R.K., Jimenez, R.A., Cluff, C.B., and Morris, G.R.
Arizona University, Tucson, Water Resources Research Center.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 104, No. IR1, p 43-58, March, 1978.  10 fig, 1 tab, 11 ref,
4 equ, 1 append.

Descriptors:  Linings, Reservoir leakage, Seepage, Seepage control, Waterproofing,
Asphaltic concrete, Laboratory tests.

A mixture of asphalt cement mixed with crumb-rubber (asphalt-rubber) has been
used successfully in highway construction for several years in Arizona and other
states.  This paper describes laboratory tests on asphalt-rubber and includes
preliminary results of an actual reservoir lining application.


78:08G-002
PREDICTION OF DEFLECTION FOR CORRUGATED PLASTIC TUBING,
Fenemor, A.D., Bevier, B.R., and Schwab, G.O.
Ohio Agricultural Research and Development Center, Columbus, Department of
Agricultural Engineering.
Paper No. 78-2542, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 13 p.  4 fig, 3 tab, 13 ref, 12 equ.

Descriptors:  Subsurface drains, Plastic pipes, Failure (mechanics), Deflection,
Pipes, Tubes, Drainage, Subsurface drainage, Installation, Soil tests.

Measured deflections of tubing buried five years ago in a silty clay showed that
the soil provides practically no side support against deflection.  With measured
deflection lag factors, the Iowa formula was the best of four methods for pre-
dicting deflection.  Recommended maximum depths of burial are tabulated for
tubing up to 381 mm diameter.


78:080-003
FAILURE CRITERIA FOR CORRUGATED-PLASTIC DRAIN TUBING,
Walker, P.N., Armstrong, C.L., and Singh, P.N.
Illinois University, Urbana, Department of Agricultural Engineering.
Paper No. 78-2439, Presented at the 1978 Winter Meeting of the American Society
of Agricultural Engineers, December 18-20, 1978, Palmer House Hotel, Chicago,
Illinois, 13 p.  8 fig, 2 tab, 5 ref, 8 equ.

Descriptors:  Plastic pipes, Subsurface drains, Failure (mechanics), Tubes,
Drainage, Subsurface drainage. Pipes, Deflection, Installation.

Results from hydraulic-capacity, pipe-stiffness, and live-load carrying-capacity
tests of permanently deflected drain tubing are presented.  These tests are
part of a continuing effort to define failure criteria for plastic drain tubing. -
                                     280

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                                SECTION XXXIX


                      MANPOWER, GRANTS, AND FACILITIES

                     EDUCATION - EXTRAMURAL (GROUP 09A)


78:09A-001
ASCE MET SECTION STRIVING TO MAKE CIVIL ENGINEERING. CURRICULA MORE PRACTICE-
ORIENTED,
Khera, R.P.
New Jersey Institute of Technology, Newark, Department of Civil Engineering.
Civil Engineering, Vol. 48, No. 1, p 75, January, 1978.

Descriptors:  Civil engineering, Engineering education.  Education, Engineering,
Evaluation.

Concerned with deficiencies in civil engineering education and the limitations
of the ECPD evaluation procedures, the ASCE Metropolitan Section Committee on
Engineering Education set out to upgrade and monitor civil engineering education.
A poll of Met Section members showed a desire for change in the direction of
civil engineering education.  Experimental review program of undergraduate
civil engineering education was approved by the Met Section Board in April, 1968.
It contemplated periodic visits to each of the undergraduate civil engineering
departments in the Metropolitan area by a team of ASCE members.  This article
discusses in brief about the activities of the ASCE Met Section, the purpose it
has served, and the procedure it follows to attain its objectives.
                                     281

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                                  SECTION XL


                    SCIENTIFIC AND TECHNICAL INFORMATION

                   ACQUISITION AND PROCESSING  (GROUP 10A)


78:10A-001
NATIONAL CONFERENCE ON MANAGEMENT OF NITROGEN IN IRRIGATED AGRICULTURE,
Pratt, P.F., Editor.
Sponsored by U.S. National Science Foundation, U.S. Environmental Protection
Agency, University of California.
Proceedings of National Conference on Management of Nitrogen in Irrigated
Agriculture, California University, Sacramento, California, p 1-442, May 15-18,
1978.  49 fig, 59 tab, 371 ref, 26 equ.

Descriptors:  Nitrogen, Nitrogen cycle, Nitrates, Irrigated land, Water quality,
Water management (applied), Conferences.

These Proceedings represent a National Conference on Nitrogen Management in
Irrigated Lands, designed to bring together users representing a diversity of
interests throughout the country for an integrated review of the findings from
the comprehensive national research effort.   The accumulated information needs
to be utilized as fully as possible by the many individuals and organizations
making decisions in current water quality planning.  This will help ensure the
emergence of appropriate and viable solutions to our water quality problems —
solutions that are sensitive to both local and national needs and priorities.
                                    282

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                                    SECTION  XLI


                          SCIENTIFIC AND  TECHNICAL  INFORMATION


                  SECONDARY  PUBLICATION AND  DISTRIBUTION  (GROUP  IOC)


 78:10C-001
 SELECTED IRRIGATION  RETURN  FLOW QUALITY  ABSTRACTS  1976,
 Skogerboe,  G.V.,  Smith,  S.W.,  and Walker, W.R.
 Colorado State  University,  Fort Collins, Colorado, Department of Agricultural
 and  Chemical  Engineering.
 Publication No. EPA-600/2-78-042, March, 1978.   311 p.

 Descriptors:  Fertilizers,  Irrigated land,  Salinity, Return flow.

 Research related  to  the  quality of  irrigation  return flow is being conducted at
 numerous institutions  throughout the western United States.  Related work is
 also underway at  other institutions  in the  United  States, as well as other
 portions of the world.   Approximately 100 sources  of material have been
 searched for  articles  pertinent to  the National  Irrigation Return Flow Research
 and  Development Program.  These articles describe water quality problems re-
 sulting  from  irrigated agriculture,  potential  technological solutions for
 controlling return flows, recent research pertinent to return flow investiga-
 tions, and  literature  associated with institutional constraints in irrigation
 return flow quality  control.   The first  annual issue SELECTED IRRIGATION RETURN
 FLOW QUALITY  ABSTRACTS covered publications printed in 1968 and 1969, while
 the  second  annual issue  lists  publications printed in 1970 and  1971, the third
 annual issue  covers  literature published in 1974 and 1975.  This annual issue
 lists publications printed  in  1976.  This report was submitted  in fulfillment
 of Grant Number R-800426 under the sponsorship of the Office of Research and
 Development,  Environmental  Protection Agency.


 78:10C-002
 GROUNDWATER POLLUTION.   PART 2.  POLLUTION FROM IRRIGATION AND  FERTILIZATION.
 VOL.  2.   1977-JANUARY, 1978.  (CITATIONS FROM THE NTIS DATA BASE),
 Brown, R.J.,  Editor.
 National  Technical Information Service, 5285 Port Royal Road, Springfield,
 Virginia  22161.
 NTIS/PS-78-0141, February,  1978.  65 p.

 Descriptors:  Abstracts, Bibliographies, Groundwater, Water pollution, Irrigation,
 Fertilization, Water pollution control, Return flow,  Research and development,
 Groundwater recharge.

 The bibliography contains abstracts of Federally-funded research covering aspects
 of groundwater pollution from  irrigation and fertilization.   The reports in-
 clude topics  dealing with the  pollution from sewage and waste water irrigation,
 land  spreading of sludges and  solid wastes,  nitrate and phosphate accumulation
 in soils, pollution control and abatement planning, salt build-up from irrigation,
 the use of  tile drains in groundwater pollution control, and groundwater recharge
 studies.


 78:10C-003
 THE PESTICIDE CONTENT OF SURFACE WATER DRAINING FROM AGRICULTURAL FIELDS—A REVIEW,
Wauchope, R.D.
 Southern Weed Science Laboratory,  Science and Education Adminstration, Federal
 Research, United States Department of Agriculture,  Stoneville,  Mississippi  38776.
 Journal of Environmental Quality,  Vol.  7, No. 4, p 459-472,  October-December, 1978.
 3 fig, 4 tab, 69 ref.

 Descriptors:  Agricultural runoff,  Surface runoff,  Runoff,  Pesticides, Water
quality, Water pollution, Herbicides, Insecticides, Reviews.
                                     283

-------
 The  literature on pesticide losses in runoff waters from agricultural fields was
 reviewed.  For the majority of commercial pesticides, total losses were found to
 be 0.5% or less of the amounts applied, unless severe rainfall conditions occur
 within 1-2 weeks after application.  Exceptions were noted for the organochlorine
 insecticides, which might lose about 1% regardless of weather pattern because of
 their long persistence; and soil surface-applied, wettable-powder formulations
 of herbicides, which might lose up to 5%, depending on weather and slope, be-
 cause of the ease of washoff of the powder.  The effects of erosion control
 practices on losses of various types of pesticides were documented.  The behavior
 and  fate of pesticides in streams receiving runoff was not clearly determined
 from the literature.  It was concluded that information on such factors as time
 and  distance of impact of a given runoff event, ability of local ecosystems to
 recover from transient pesticide concentrations, and dissipation or concentration
 processes in aquatic ecosystems will have to be obtained before "edge-of-field"
 pesticide losses can be related to water quality in receiving waters.


 78:10C-005
 CHOICES IN IRRIGATION MANAGEMENT,
 British National Committee.
 International Commission on Irrigation and Drainage.
 ICID Bulletin, Vol. 27, No. 2, p 62-64, July, 1978.

 Descriptors:  Water management (applied), Irrigation, Groundwater, Irrigation
 programs, Pricing, Agriculture, Crop production. Water demand, Project post-
 evaluation.

 A "workshop" on choices in irrigation management was organized by the Agricultural
 Administration Unit of the Overseas Development Institute and held at the Univer-
 sity of Kent, Canterbury.  The workshop was attended by 35 participants, of whom
 12 came from eight different countries in Asia, Africa and Latin America.  The
majority of these had extensive first-hand experience of irrigation management
 at project level.  Twenty-one papers were presented and discussed.  This paper
 is a summary of these 21 papers discussed under several categories of irrigation
management.


 78:10C-006
ANNOTATED BIBLIOGRAPHY FOR WATER QUALITY MANAGEMENT, FIFTH EDITION,
Hurd, M.
Water Quality Management Information Center, Program Management Branch, Water
Planning Division (WH/554), Washington, D.C.  20460.
EPA Report, Division of Water Planning, Washington, D.C., April, 1978.  64 p.

 Descriptors:  Bibliographies, Abstracts,  Water quality. Water quality act, Water
quality control,  Return flow, Water pollution, Water management (applied),
Waste water (pollution), Waste water treatment.

This bibliography was prepared by U.S. Environmental Protection Agency to assist
 those agencies engaged in water quality management planning.  The references
 cited have been selected for their applicability to 208 planning and for their
availability.  Each reference is followed by a short abstract, and whenever
possible, by detailed price and ordering information.


 78:10C-007
BEST MANAGEMENT PRACTICES FOR AGRICULTURE AND SILVICULTURE,
Loehr,  R.C., Haith, D.A., Walter, M.F., and Martin, C.S., Editors.
Cornell University, Ithaca, New York, College of Agriculture and Life Sciences.
Proceedings of the 1978 Cornell Agricultural Waste Management Conference.  154
 fig,  159  tab, 490 ref, 57 equ.
 (See 78:05G-071)
                                   284

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                                  SECTION XLII

                                  AUTHOR INDEX
Aase, J.K.
          78:020-006
          78:07B-007

Abbott, J.L.
          78:02K-021
Abede, B.
          78:020-026
Abrol, I.P.
          78:02G-023

Acharya, C.L.
          78:02G-023

Adams, J.A.
          78:021-015

Adams, J.E.
          78:04A-017

Adrian, D.D.
          78:05A-008

Adriano, D.C.
          78:021-024

Aflatouni, M.
          78:021-034

Aggelides, S.
          78:020-067

Agri. Engineering
          78:06E-005

Agron, N.A.
          78:02K-006

Ahlert, R.C.
          78:058-014
Akiri, B.
          78:078-010
Al-Layla, M.A.
          78:05G-020

Alberts, E.E.
          78:058-008
Alemu, A.
          78:03F-002
Alexander, G.H.
          78:03F-066

Alexander, G.V.
          78:02K-072

Alexander, M.
          78:058-054
          78:050-005
Ali, S.M.A.
          78:03F-097

Aljibury, F.K.
          78:03F-077
          78:03F-080

Allen, S.E.
          78:021-007

Allmaras, R.R.
          78:021-008
          78:07B-005
Alt, K.F.
          78:068-010
Alvarez, D.
          78:05G-016

Alvi, A.A.
          78:03F-040

Anunon, D.C.
          78:06A-016

Andersen, J.C.
          78:05G-035
          78:05G-075

Anderson, A.
          78:02G-031

Anderson, L.W.J.
          78:058-048

Anderson, O.E.
          78:020-037

Anderson, T.D.
          78:058-049

Archer, E.
          78:04A-010

Ardekani, E.R.
          78:020-029

Ariathurai, R.
          78:02J-002

Armstrong, C.L.
          78:080-003

Aronsson, G.
          78:02J-014

Arulanandan, K.
          78:02J-002

Ashcroft, G.L.
          78:021-025
                                      285
Ashley, D.A.
          78:021-001

Avnimelech, Y.
          78:05G-002

Ayars, J.E.
          78:078-032

Ayers, R.S.
          78:03F-015
          78:058-020

Ayres, G.E.
          78:03F-108

Bailey, G.W.
          78:040-003
          78:050-047
          78:06A-003

Baker, D.E.
          78:078-004

Baker, F.G.
          78:02G-028

Baker, J.L.
          78:05A-020
          78:05G-029

Bakr, A.A. .
          78:02F-007
          78:02F-023

Baligar, V.C.
          78:021-021
          78:021-023
          78:02K-026
          78:02K-070

Bar-Yosef, B.
          78:02K-004
          78:02K-037
          78:07B-010

Barber, S.A.
          78:021-012
          78:021-021
          78:021-023
          78:02K-026
          78:02K-070

Barefoot, A.D.
          78:03F-097

Barfield, B.J.
          78:02J-009
          78:02J-022

Barinas, F.A.
          78:088-006

-------
Barkely, P.W.
           78:03F-011

Barker, J.
           78:02F-026

Barnes, P.L.
           78:02G-060

Barnhisel, R.I.
           78:02J-022

Barrett, J.W.H.
           78:03F-031

Bartelt, G.E.
           78:040-001

Bartsch, A.F.
           78:050007
Batu, V.
          78:02G-009
          78:02G-044
Bauder, J.W.
          78:021-006
Bauer, A.
          78:021-006
          78:03F-001
Baughman, G.L.
          78:05B-030

Bayazit, M.
          78:02J-016
Bear, J.
          78:02F-010
Beauchamp, E.G.
          78:02F-002
Beck, L.A.
Beese, F.
          78:056-023
          78:02K-015
Ben-Asher, J.
          78:02G-041
          78:03F-007
          78:03F-026

Bendixen, W.E.
          78:03F-010

Bennett, J.P.
          78:07B-006

Benton, A.R., Jr.
          78:020-004
Benz, L.C.
          78:03F-125
Berkowitz, S.J.
          78:06E-015

Berle, P.A.A.
          78.-05G-068

Bettany, J.R.
          78:021-033
          78:02K-055

Beutel, J.
          78:03F-080

Bevier, B.R.
          78:08G-002

Beyerlein, D.C.
          78:05G-065

Bezdek, J.C.
          78:086-004

Bezdicek, D.F.
          78:02G-026

Bhuiyan, s.'I.
          78:03F-062

Bielorai, H.
          78:021-003
          78:030-004
          78:03F-095

Biggar, J.W.
          78:03F-015

Binder, C.W.
          78:05G-011

Bingham, F.T.
          78:021-015

Biswas, C.R.
          78:050-021

Black, J.D.F.
          78:021-002

Blackard, J.
          78:040-004
Blair, J.
          78:03F-035
          78:03F-047
Berg, C.W.
Blanchard, B.
          78:02G-031

Blaser, R.E.
          78:021-011

Blevins, D.G.
          78:021-014

Bliven, L.F.
          78:06E-009
          78:07B-026
Bloom, P.R.
          78:07B-018

Bloomsburg, G.L.
          78:02G-057

Bobovnikova, Ts.I.
          78.-05B-031
Boels, 0.
          78:02G-085
Bogardi, I.
           78:08E-001

Boggess, S.F.
           78:021-010

Bondurant, D.T.
           78:02J-006

Bondurant, J.A.
           78:07A-002

Borcherding, M.A.
           78:05A-020

Bornstein, J.
           78:076-035

Borrelli, J.
           78:03F-096

Bottcher, A.B.
           78:02J-019

Bottcher, A.D.
           78:05B-068

Bottrall, A.F.
           78:06A-013

Botzan, M.
           78:03F-109

Boulton, N.S.
           78:02F-012

Bouwer, H.
           78:02F-027

Bovey, R.W.
          78:058-023
          78:05B-026

Bowles, D.S.
          78:058-010

Bowman, R.A.
          78:02K-014
          78:078-014

Boyer, J.S.
          78:021-018

Boysen, S.M.
          78:08A-004
          78:04A-013
                                      286

-------
Bradford, J.M.
          78:040-006

Braud, H.J.
          78.-03F-089

Brazhnikova, L.Y.
          78:05B-032

Brenner, S.
          78-.02K-006

Bresler, E.
          78:02G-004
          78:026-034
          78:03F-093

British Natl. Committee
          78:10C-005

Broadbent, F.E.
          78:021-030
          78:05A-009

Brockway/ C.E.
          78:03F-101
          78:050-038
          78:06B-002
          78:07A-002

Brower,  D.L.
           78:02K-058

Brown, B.M.
           78:02F-011

Brown, D,J.
           78:020-022
 Brown,  D.S
           78:05B-028
 Brown,  F.B.
           78:050-035

 Brown,  K.W.
           78:021-037
           78.-05A-002
           78:058-056
           78:05G-039

 Brown,  M.J.
           78:07A-002

 Brown,  R.J.
           78:100002

 Brown,  R.M.
           78.-02F-026

 Bruce,  D.A.
           78:03F-091

 Bruce,  R.R.
           78:078-025

 Bruch,  J.C. , Jr.
           78:04A-002
Buchanan, B.A.
          78:078-015

Buchta, H.G.
    *      78:04A-009

Bucks, D.A.
          78:03F-032
          78-.Q3F-064

Bulat, J.A.
          78:03F-029

Buresh,  R.J.
          78:02K-068

Burge, W.D.
          78:058-005

Burnett, E.
          78:04A-017
          78:058-023
          78:058-024
          78:058-026

Burwell, R.E.
          78:04A-012
          78:058-008

Busch, J.R.
          78:03F-101
          78:04A-013
          78:068-002

Bush,  D.S.
          78:05A-012

Busman,  J.D.
          78-.03F-118

Busscher, W.J.
          78:021-004

Butcher, W.R.
          78:06C-002

Cahill,  T.H.
          78:05G-067

Caldwell, A.C.
           78:021-009

Callahan, C.A.
           78:05C-007

 Callies, R.E.
           78:03F-098

 Cameron, D.R.
           78:02G-084
           78:02K-071
           78:058-043
 Camp, C.R.
           78-.04B-005
Campbell, K.L.
          78:02A-004

Cannon, J.R.
          78:050-035

Canode, C.L.
          78:03F-024

Carder, D.R.
          78:06A-014

Carlson, D.
          78:050-073

Carson, P.L,
          78:021-005

Carter, C.E.
          78:046-005

Carter, D.L.
          78:020-039

Cassel, O.K.
          78:021-006
          78:03F-001
          78:05B-019

Cauchois, S.
          78:06B-021

Cavallaro,  N.
          78.02K-034

Chandra, S.
          78:02J-001
                                                          Chang, C.
                                                                     78:058-043
 Chaudhry,  F.H.
           78:03F-030

 Chauhan, H.S.
           78:02F-016

 Cheng,  H.H.
           78:058-029

 Cherkhanov,  Yu.P.
           78:058-031

 Cherry, J.A.
           78:02F-026

 Chesness,  J.L.
           78:03F-061

 Chichester,  F.W.
           78.-02K-009
           78:058-025

 Chien,  S-H.
           78:02K-066
 Campbell, G.S.
           78:02G-020
                              Chiu, C.L.
           78:088-011
                                        287

-------
Chiu, C-L.
          78:02E-005

Choi, E.C.C.
          78:02F-014

Chorley, D.W.
          78:02F-022

Christenson, D.R.
          78:021-043
Chu, S.T.
          78:02G-052
Ciravolo, T.G.
          78:021-024

Clapp, R.B.
          78:02G-073

Clark, R.T.
          78:03F-096

Clarke, J.M.
          78:021-038

Clarke, R.T.
          78:02E-001

Clemmens, A.J.
          78:03F-064
          78:076-011
          78:076-027

Clift, T.R.
          78:02E-010

Cluff, C.B.
          78:08G-001
Cohen, B.
          78:05G-067
Cohon, J.L.
          78.-04A-004

Cole, C.V.
          78:02K-014

Conklin, L.R.
          78:068-002

Conner, B.J.
          78:058-006

Contractor,  D.N.
          78:02J-024
Cook, F.D.
          78:03F-029
Cook, K.A.
          78:078-009

Coote, D.R.
          78:05A-016
          78:056-046
Cotnoir, L.J.
          78:056-011

Couvillon, G.A.
          78:03F-061
COX, C.M.
Cox, F.R.
          78:058-041
          78:02K-051
Cronan, C. S.
          78:02G-005

Crops & Soils Magazine
          78:03F-050

Currier, J.B.
          78:058-065

Curtis, L.M.
          78:03F-078

Cushman, J.
          78:02G-048

D'Arge, R.C.
          78:056-035
Dagan, G.
          78:02F-017
          78:02G-018
Dale, R.F.
          78:02A-001
          78:02G-038

Dalton, F.N.
          78:021-013

Dancette, C.
          78:036-001
Dasberg, S.
          78:026-050
          78:056-002
Davey, B.G.
          78:02K-063

Davidson, J.M.
          78.-03F-013
          78:056-018
          78:056-027

Davies, R.I.
          78:076-019

Davis, C.L.
          78:026-058

Davis, H.H.
          78:056-072

Davis, M.J.
          78:056-063
Davis, S.S.
          78:02J-005
Day, A.D.
          78:03F-002
De Datta, S.K.
          78:02K-043

De Kimpe, C.R.
          78:02K-050
De, S.K.
          78:02J-001
Dean, J.D.
          78:056-064

Decoursey, D.6.
          78:02J-012

Dedrick, A.R.
          78:03F-034
          78:03F-128
          78:03F-130
DeHaan, R.
          78:056-046
                             Dehan, K.
                                       78:03C-005
DeJong, R.
          78:056-043

Delaney, R.H.
          78:03F-096

DeLucia, R.
          78:058-009

Demchenko, A.S.
          78:056-032

DeMeterio, J.L.
          78:058-040

DeMichele, D.
          78:056-039

Dempster, T.H.
          78:066-014

DeRoo, H.C.
          78:02Q-019

DeSmedt, F.
          78:026-006
          78:026-015

DeTar, W.R.
          78:03F-059
Deuel, L.
          78:056-039
                                        288

-------
 Deuel,  L.E.
           78:021-037
           78J05B-056

 Develice,  R.L.
           78:07B-015

 Devitt,  D.
           78:02G-046

 Dideriksen,  R.I.
           78:02J-021

 Dirksen, C.
           78j02G-011
           78:020-016
           78:03F-110
           78:05G-044

 Diskin, M.H.
           78:02A-005

 Dixon,  J.B.
           7S:02K-025

 Doering, E.J.
           78:03F-125

 Doll, E.G.
           78:021-043

 Dominguez, J.
           78:021-036

 Doner, H.E.
           78.-02K-064

 Doney, D.L.
           78:03F-028

 Donigian, A.S.
           78:056-065
           78:05G-072

 Donnan, W.W.
          78:05G-025

 Dooley, H.L.
          78:021-022

 Dooris, P.M.
          78:021-027

 Douglas, E.
          78:020-024

Douglas, L.A.
          78:078-003

Drablos, c.J.W.
          78:03F-124
          78:040-001

Draperi D.W.
          78:05A-016

Duble, R.L.
          78:05A-002
 Duckstein,  L.
           78:08E-001

 Dudek,  D.J.
           78:068-001
 Duich,  J.M.
 Duke,  H.
           78:03F-003
           78:021-041
 Duke, H.R.
           78sQ2F-020
           78;03F-069
           78:03F-116
           78:03F-117
           78:043-002
           78:05G-077

 Duseja, D.R.
           78:02K-016

 Dusek, D.A.
           78:021-042

 Duxbury, J.M.
           78:02K-067
           78:Q5B-046

 Dworsky, R.F.
           78:05G-050

 Eagleson,  P.s.
          .78:02A-007
           78:02A-008
           78:02A-009
           78:026-001
           78:020-005
           78:02G-068
           78:026-074

 Eastburn,  R.P.
           78t02D-003
           78:058-037

 Edling, R.J.
          78:03F-117

 Edwards, A.L.
           78:02F-006

 Edwards, W.M.
          78:05B-006

Edworthy, K.J.
          78:048-010

Eggert,  K.G.
          78:06A-015

Eisenhauer, D.E.
          78:03F-083

El-Ghansry,  W.M.
          78:020-080
 Elliott,  L.F.
           78:05G-076

 Ellis,  J.W.
           78:078-025

 Elprince, A.M.
           78:058-042

 Elrick,  D.E.
           78:02G-012

 England,  M.
           78:03F-060

 Enkiri, N.K.
           78:05B-005

 Erbach, D.C.
           78:03F-108

 Erickson, C.J.
           78:021-016

 Erie, L,J.
           78:03F-034
           78:03F-128
           78:03F-130

 Estes, J.E.
           78:060-001

 Ethridge, W.J.
           78:021-001

 Evans, D.W.
           78:02G-026

 Evans, R.G.
           78:058-022
           78:05G-009
           78:05G-011

 Fangmeier, D.D.
           78:02G-083
           78:03F-099
           78:03F-118

 Fanning,  D.S.
          78:021-032

 Federer,  C.A.
          78:02A-011

 Fenemor, A.D.
          78:08G-002

 Fenster, c.R.
          78:03F-113

Ferguson, J.A.
          78:02K-065

Ffolliott, P.P.
          78:06A-014

 Firestone, M.K.
          78:02K-029
                                      289

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Fischbach, P.
          78:03F-049

Fischbach, P.E.
          78:021-040
          78:03F-033
          78:03F-083
          78.-03F-086

Fisher, H.D.
          78:03F-115

Fitzsimmons, D.W.
          78:04A-013
          78:066-002

Fixen, P.E.
          78:021-005
Flaig, W.
          78:07B-003
Flores, E.Z.
          78:02F-009
          78:04A-001

Focht, D.D.
          78:02G-050
          78:02K-057
          78:07B-023
Fok, Y-S.
          78:030-001
Follett, R.F.
          78:03F-125

Follett, R.H.
          78:03F-113

Ford, H.W.
          78:03F-090

Foster, G.R.
          78:02J-005
Fox, R.H.
          78:07B-013
          78:076-024
Frank, J.F.
          78:050-061

Frenkel, H.
          78:020-010
          78:020-045
          78:020-046
          78:030003
          78:050-036
Fried, M.
          78:021-030
Frind, E.G.
          78:02F-022
          78:04B-011
Frink, C.R.
          78:020-019

Fritton, D.D.
          78:021-004
          78:06D-002
Fritz, P.
          78:02F-026
Frobel, R.K.
          78:080-001

Frota, J.N.E.
          78:021-028
          78:021-029

Fryrear, D.W.
          78:04A-010
Fuchs, M.
          78:020-020
          78:03F-007
Gabriels, D.
          78:02J-027

Oakstatter, J.H.
          78:050007

Galinato, G.D.
          78:03F-101

Gamble, J.
          78:03F-088

Gaponyuk, E.I.
          78:050002

Gardner, B.D.
          78:05G-022

Gardner, D.M.
          78:06E-002

Gardner, W.R.
          78:02G-009
          78:02G-062
          78:021-013

Garner, B.J.
          78:048-006

Gast, R.G.
          78:05A-004

Gelhar, L.W.
          78:02F-007
          78:02F-023
          78:04A-001
          78:058-039

Gembrell, R.P.
          78:02K-048

Gerard, C.J.
          78:030002
Gerdts, M.
          78:03F-080

Gerrish, J.B.
          78:05A-018

Gharaaty-Sani, R.
          78:06A-005

Ghate, S.R.
          78:02G-081

Ghildyal, B.P.
          78:020-076

Gibbs, K.C.
          78:060002

Gifford, G.F.
          78:04A-006
          78:05B-012

Gilbert, R.G.
          78:03F-032
          78:058-047

Gilley, J.R.
          78:03F-049
          78:03F-072

Gilliam, J.W.
          78:020-050
          78:02K-048
          78:05G-018
          78:050-034
          78:050-074

Gilmour, C.M.
          78:050006

Gilmour, J.T.
          78:02K-065

Gilmour, R.
          78:05G-060

Ginberg, P.
          78:068-019

Ginn, L.H.
          78:078-001

Giordano, P.M.
          78:03F-025

Giraldez, J.V.
          78:020-047

Giskin, M.
          78:02G-030

Gleason, V.E.
          78:06E-007

Goertzen, J.O.
          78:020-010
          78:05G-036
                                       290

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Goldberg, D.
          78:03F-007

Golovleva, L.A.
          78:02K-042

Gordos,  J.D.
          78:048-009

Gormly,  J.R.
          78:05A-010

Gosling, R.
          78:03F-084

Gould, W.D.
          78:03F-029

Gove, S.K.
          78:06E-002

Graham,  E.R.
          78:07B-009

Grant, M.C.
          78:078-028

Grass, L.B.
          78:02K-052

Green, D.B.
          78:058-007
Green, P.
          78:02J-018
Greer, J.D.
          78:05G-043

Grenney, W.J.
          78:058-010

Greydanus, H.W.
          78:043-004

Griffin, S.G.
          78:03F-058

Griffis, C.L.
          78:02K-065

Griffis, W.
          78:021-022

Groszyk, W.S.
          78:06E-010

Guitjens, J.C.
          78:058-002

Guntermann, K.L.
          78:06E-002
Gur, Y.
          78:02K-008
Guthrie, T.F.
          78:02K-067

Gutiahr, A.L.
          78:02F-007
          78:02F-023
          78:04A-001
Haan, C.T.
Hadas, A.
          78:02A-010
          78:02J-009
          78:02K-004
          78:030-003
Hagan, R.M.
          78:03F-079

Hagedorn, C.
          78:058-004
          78:058-052

Hageman, L.
          78:02K-059
Hagin, J.
          78:02K-005
Haith, D.A.
          78:05G-071
          78:068-017

Halderman, A.D.
          78:040-007
                             Hall, A.E.
          78:038-001
Hall, J.K.
Ham, G.E.
          78:05A-003
          78:021-009
Hamad, S.N.
          78:040-008

Hamilton, A.
          78:06E-014

Hamilton, M.
          78:050-001

Hammond, J.
          78:03F-107

Hammond, L.C.
          78:03F-008

Hampieke, U.
          78:06G-002

Hancock, C.V.
          78:05G-062
Gureghian, A.B.
          78:02F-019
                             Hankin, L.
          78:078-034
Hanks, R.J.
          78:021-025
          78:03F-056

Hann, R.W., Jr.
          78:06A-008

Hannoura, A.A.
          78:08B-012

Hansen, D.T.
          78:058-004

Hanson, C.L.
          78:021-016

Hanson, E.G.
          78:03F-063

Hanson, R.E.
          78:03F-071

Harmon, W.C.
          78:02J-025

Harpaz, A.
          78:05G-002

Harper, W.C.
          78:05G-069

Harrington, J.
          78:058-009

Harrison, D.S.
          78:03F-065

Hartwig, N.L.
          78:05A-003

Hauck, R.D.
          78-.03F-018

Haun, J.R.
          78:021-035

Hauser, V.L.
          78:04A-018

Hawkins, R.H.
          78:04A-006
          78:05B-038

Hayes, J.C.
          78:02J-022

Hayes, R.O.
          78:06G-001

Hayhoe, H.N.
          78:02G-001
          78:02G-027

Heady, E.O.
          78:04A-003
          78:05G-003
          78:068-010
          78:06E-021
                                       291

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Heaney, J.P.
          78:06A-016

Heatherly, L.G.
          78:078-001

Hebb, E.A.
          78:056-035

Hedstrom, W.E.
          78:03F-096

Heermann, D.
          78:021-041

Heermann/ D.F.
          78:03F-069
          78:03F-104
          78:05G-077

Helvey, J.D.
          78:05B-049

Helweg, O.J.
          78:05G-016

Hendrickson, L.L.
          78:03F-004
          78:03F-005
          78:078-002

Henriksen, A.
          78:02K-044
Henry, C.
          78:03F-052
          78:03F-114
          78:07A-001
Hermsmeier, L.F.
          78:030-006

Herrera, I.
          78:02F-009

Hesseltine, B.B.
          78:058-011

Hiatt, A.J.
          78:021-014

Hidlebaugh, A.R.
          78:02J-021

Highsmith, R.M.
          78:06A-007

Hiler, E.A.
          78:048-008

Hill, J., IV
          78:06A-002
Hill, R.W.
Hillel, D.
          78:02G-021

Hills, F.J.
          78:021-030

Hipel, K.W.
          78:02E-004
          78:02E-008
          78:02E-009

Hira, G.S.
          78:02K-036

Hoeft, R.G.
          78:02K-017
          78:02K-018

Hoffman, D.L.
          78:02K-061

Hoffman, G.J.
          78.021-015
          78:056-044

Hogg, T.J.
          78:021-033
          78:02K-055

Holburt, M.B.
          78:06E-006

Holmes, E.E.
          78:02K-016

Hoover, J.R.
          78:020-058

Hornberger, G.M.
          78:02G-073

Horner, G.L.
          78:068-001

Horney, L.F.
          78:06E-009
Horta, M.
          78:021-036
Hossner, L.R.
          78:02K-047
          78:05C-001

Houck, M.H.
          78:04A-004

Howald, R.A.
          78:02K-059

Howell, T.A.
          78:088-006
          78:06A-006
Howitt, R.
Hoyt, G.D.
          78:058-003

Hliber, M.J.
          78:02G-011
          78:020-016

Huggins, L.F.
          78:02J-005
          78:02J-019

Hughes, T.C.
          78:088-010

Humenik, F.J.
          78:06E-004
          78:078-026

Humpherys, A.
          78:03F-053

Humpherys, A.S.
          78:03F-115
Hunt, B.
          78:058-017
Huntley, D.
          78:02F-021
Kurd, M.
          78:100006
Hurst, R.L.
          78:03F-028

Huszar, P.C.
          78:05G-012
          78:05G-013
          78:05G-014
          78:05G-015
          78:050-033

ICID Committee
          78:03F-042
                             Idso, S.B.
Ikan, R.
          78:020-006
          78:03F-112
          78:02K-006
          78:066-021
Imberger, J.
          78:02H-001

Ingvalson, R.D.
          78:05G-044

Irrigation Age
          78:03F-036
          78:03F-037
          78:03F-038
          78:03F-046
          78:03F-051
          78:048-0.14
                                      292

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Irrigation Journal
          78:03F-043
          78:03F-044

Ishikawa, T.
          78:02J-013
Isu, E.O.
          78:02E-005
          78:088-011
Ivarson, K.C.
          78:02K-071
Ivey, G.
          78:02H-001
Jackson, E.B.
          78:03F-002

Jackson, L.G.
          78:04A-009

Jackson, R.D.
          78:03F-112

Jackson, T.L.
          78:03F-012

Jacobs, J.J.
          78:03F-096

James, D.W.
          78:03F-028

James, W.P.
          78:020-004

Jarrett, A.R.
          78:02G-058
          78:02G-059
          78:03F-102

Jenkins, D.A.
          78:02K-045
          78:078-019

Jensen, J.R.
          78:060-001

Jensen, H.E.
          78:020-007
          78:020-008

Jensen, P.A.
          78:063-020

Jeppson, R.W.
          78:083-010

Jessup, R.E.
          78:02G-013

Jimenez, R.A.
          78:080-001

Jobson, H.E.
          78:02E-003
Johannessen, M
          78:02K-044

Johnson, A.T.
   ,      78:078-032

Johnson, C.W.
          78:02J-008

Johnson, D.
          78:068-009

Johnson, H.P.
          78:05A-020

Johnson, J.S.
          78:05G-049

Johnson, J.T.
          78:021-017

Johnson, R.R.
          78:021-018

Johnston, W.R.
          78:056-023

Jones, J.P.
          78:058-037
          78:056-059

Joung, H.M.
          78:058-002

Jurgens, S.K.
          .78:021-018

Jurinak, J.J.
          78:02K-024
          78:07A-003

Jury, H.A.
          78:026-045
          78:026-046
          78:026-065
          78:030003
          78:058-021

Kafkafi, U.
          78:021-026
          78:02K-004
          78:02K-037

Kalbasi, M.
          78:02K-010
          78:02K-013

Kamprath, E.J.
          78:02K-069

Kanwar, R.S.
          78:02F-016

Karickhoff, S.W.
          78:058-028

Karimian, N.
          78:02K-051
Karmeli, D.
          78:03F-020
          78:03F-054
          78:03F-126

Karr, J.R.
          78:06E-002

Kaufman, D.D.
          78:078-016

Kaufmann, M.R.
          78:021-015

Kaushik, N.K.
          78:05B-064
Kay, B.D.
          78:02C-001
Kearney, P.C.
          78:078-016

Keasler, L.C.
          78:05G-055

Keefer, T.N.
          78:02E-003

Keener, M.R.
          78:021-037

Keeney, D.R.
          78:03F-004
          78:03F-005
          78:078-002

Keisling, T.C.
          78:02G-013
          78:02K-041

Keller, J.
          78:03F-127
          78:088-005

Kelly, G.D.
          78:02J-010

Kelso, G.L.
          78:03F-102

Kennedy, H.G.
          78:021-007

Kepler, K.
          78:056-073

Ketcheson, J.W.
          78:02F-002

Khaleel, R.
          78:05A-017
Khan, N.A.
Khan, P.
          78.-02K-003
          78:02K-003
                                      293

-------
Khanjani, M.J.
          78:020-057

Khanna, P.K.
          78:02K-015

Khera, R.P.
          78:09A-001

Kibler, D.F.
          78:060-002

Kikkawa, H.
          78:02J-013

Kincaid, D.C.
          78:03F-116

King, L.G.
          78:06A-004
          78:06A-005

Kinnell, P.I.A.
          78:02J-018

Kirkham, D.
          78:02F-001
          78:02G-048
          78:05B-062

Kirkham, M.B.
          78:021-031

Kissel, D.E.
          78:02K-009
          78:02K-020

Klameth, L.C.
          78:02K-028

Kleinraan, A.P.
          78:05G-035
          78:05G-075

Klepper, B.
          78:078-005

Klepper, R.
          78:058-001

Kling, G.F.
          78:058-052

Knight, J.H.
          78:02G-012

Knight, W.A.
          78:050-062

Knisel, W.G., Jr.
          78:02E-002

Kobzev, V.A.
          78:050002

Koehler, F.A.
          78:06E-009
          78:078-026
Koeppe, D.E.
          78:021-010

Kohberger, R.C.
          78:05A-006
Lai, S-H.
          78:02K-024
Kohl, D.H.
Kohn, B.
          78:02K-066
          78:04D-002
Konwinski, G.R.
          78:02J-028

Korcak, R.F.
          78:021-032

Korotova, L.G.
          78:058-032
Kort, R.
          78:078-032
Kowalenko, C.G.
          78:02K-071

Kramer, L.A.
          78.-04A-012

Krishnaraurthi, N.
          78:02G-049

Kroutil, W.F.
          78:03F-048
Kruh, G.
          78:02K-005
Kruse, E.G.
          78:050-028

Kuepper, G.
          78:068-009

Kuhaida, A.J.
          78:078-033

Kuhner, J.
          78:068-019

Kuiper, L.K.
          78:02F-024

Laag, A.E.
          78:03F-010

Labeda, D.P.
          78:058-054

Laflen, J.M.
          78:02J-006
          78:050-029

Lagerwerff, J.V.
          78:02K-058
Lake, J.E.
Lai, P.
          78:05G-048
          78:03F-022
Lambert, J.R.
          78:021-020

Landa, E.R.
          78:02K-033
          78:05A-022

Landwehr, J.M.
          78:05A-015

Langdale, G.W.
          78:040-003

Langford, K.J.
          78:02E-010

Langhetee, E.J.
          78:04B-013

Langton, D.N., III
          78:058-011

Lapina, N.F.
          78:058-033

Larsen, R.
          78:04A-016
          78:08A-001

Larson, C.L.
          78:04A-015

Larson, F.R.
          78:06A-014
Lash, 0.
          78:02A-011
Laverdiere, M.R.
          78.-02K-050
Law, A.G.
          78:03F-024
Layton, D.W.
          78:048-001

Leggett, J.E.
          78:021-014

Lembke, W.D.
          78:03F-124

Leonard, R.A.
          78:040-003

Lesczynski, D.B.
          78:078-002
                                        294

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Letey, J.
          78:03F-OZ5
Loewen-Rudgers, L.A.
          78:02K-010
Lettenmaier, D.P.
          78:05A-007
Leung, S.
Levin, I.
Levy, Y.
          78:068-021
          78:02G-030
          78:05G-002
          78:03C-004
Lewen-Rudgers, L.A.
          78:02K-013

Lewis, G.C.
          78:04A-013

Lewis, W.M.
          78:076-028
Li, R.M.
          78:06A-015
          78:083-001
Liang, C.N.
          78:05A-005

Libby, L.W.
          78:06E-014

Liegel, E.A.
          78:03F-005

Liesemeyer, W.W.
          78:04A-009

Liggett, J.A.
          78:02F-008

Lilly, J.P.
          78:02K-019
Lin, S.H.
          78.-02G-061
Lindsay, W.L.
          78:02K-031
          78:073-012

Little, W.C.
          78:02J-011

Liu, P.L.-P.
          78:02F-008

Loch, J.P.G.
          78:020-001

Loehr, R.C.
          78;05G-071
Log^n, T.J.
                             Loh, A.
          78:02K-032
          78:058-003
          78:058-007
          78:058-026
Lomen, D.O.
          78:020-017
          78:020-041

Long, R.B.
          78:068-002

Longenbaugh, R.A.
          78:020-049

Longley, T.S.
          78:02J-015

Loudon, T.L.
          78:05A-018

Lovell, A.D.
          78:078-025

Lovely, W.G.
          78:03F-108

Lowe, R.H.
          78:021-014

Ludwick, A.E.
          78:03F-057
Lund, L.J.
          78:02G-050
          78:03F-010
          78:078-023
Maas, E.V.
          78:050-044

MacDonald, E.M.
          78:050-046

MacKenzie, A.J.
          78:02K-052

MacMillan, J.R.
          78:02F-007
          78:02F-023

Madison, F.W.
          78:05A-019

Magdoff, F.R.
          78:03F-023

Mahannah, C.N.
          78:058-002
Maji, C.C.
          78:04A-003

Malekuti, A.
          78:058-012

Maloney, R.C.
          78:058-065

Manges, H.L.
          78:03F-123

Manley, R.E.
          78:02A-002

Mansell, R.S.
          78:03F-008
Mao, L-T.
          78:03F-123
Marian, M.B.
          78:03F-068

Marsee, C.W.
          78:06C-001

Martel, Y.A.
          78:02K-050

Martin, C.S.
          78:05G-071

Martin, D.
          78:03F-060

Martin, D.F.
          78:021-027

Masarik, D.
          78:058-055

Matlin, R.W.
          78:03F-086

McBean, E.
          78:056-009

McBride, M.B.
          78:02K-034
          78:07B-018

McCallister, D.L.
          78:02K-032

McColl, J.G.
          78:05A-012

McCorquodale, J.A.
          78.08B-012

McCoy, E.L.
          78:058-052

McDowell, L.L.
          78:02J-025
          78:050-043
                                      295

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McElwee, C.D.
         78:02A-003

McFee, W.W.
         78:058-055

McGrann, J.M.
         78:02J-020
         78:063-012

McGregor, K.C.
         78:05G-043

McGuirk, M.
         78:078-035

McKusick, R.B.
         78:068-001

McKeyes, E.
         78:02G-024

McLean, E.O.
         78:058-003

McLeod, A.I.
         78:02E-004
         78:02E-008
         78:02E-009

McNeal, B.L.
         78:03F-016

McWhorter, D.B.
         78:02F-020
         78:048-002

McWilliams, E.L.
         78:05C-001

Meek, B.D.
         78:02K-052

Mein, R.G.
         78:02F-011

Menzel, R.G.
         78:05G-008
         78:05G-037

Merculiev, O.
         78:03F-10?

Merkle, M.G.
         78:058-023

Merriam, J.L.
         78:03F-100

Merrill, S.D.
         78:03F-110

Mevorach, J.
         78:088-003
Meyer, J.
Meyer, L.D.
         78:02J-025

Meyer, R.E.
         78:058-023
         78:058-026

Michener,  D.W.
         78:048-009

Mikkelsen, D.S.
         78:02K-043

Milberg, R.P.
         78:02K-058

Miles, N.M.
         78:02K-073

Miller, D.E.
         78:078-021

Miller, J.B.
         78:058-047

Miller, M.R.
         78:02J-007

Miller, P.J.
         78:056-016

Miller, R.D.
         78:02G-034

Miller, R.J.
         78:03F-010

Miller, T.K.
         78:068-003

Miller, W.W.
         78:058-002

Mills, W.C.
         78:02E-002

Miner, G.S.
         78:02K-019

Minzoni, A.
         78.-02F-009

Miranowski,  J.A.
         78:068-010

Mitchell,  B.D.
         78:02J-026

Mitchell,  W.H.
         78:058-011

Miyamoto,  S.
         78:056-001

Moberg, E.L.
         78:03F-003
Modi, M.S.
          78:03F-022

Moldenhauer, W.C.
          78:02J-027

Monke, E.J.
          78:02J-019
          78:058-068

Moore, I.e.
          78:05A-019

Moore, I.D.
          78:04A-015

Moore, R.J.
          78:02E-001

Morehart,  A.L.
          78:058-011

Morel-Seytoux, H.J.
          78:02G-063
          78:026-072

Morgan, R.M.
          78:03F-103

Morozova,  G.K.
          78:058-031

Morris, G.R.
          78:086-001

Morrow, C.T.
          78:02G-059

Morse, W.L.
          78:020-001

Mortvedt,  J.J.
          78:020-032
          78:02G-033
          78:03F-025

Mosier, A.R.
          78:05C-003

Motz, L.H.
          78:02F-018

Mousavi, S.-F.
          78:02F-001

Mualem, Y,
          78:02F-010
          78:026-018
          78:020-042
          78:026-063

Mubarak, A.
          78:02K-059
         78:068-012
                                       296

-------
Muckleston, K.W.
          78:06A-007

Mueller, R.T.
          78:02K-072

Mulkey, L.A.
          78:05G-064

Muller, R.N.
          78:02K-011
          78:040-002

Munson, B.B.
          78:078-033

Murabayashi, E.T.
          78:030-001

Murdoch, L.W.
          78:03F-027

Murphy, L.S.
          78:05G-007

Murphy, T.A.
          78:06E-011

Musick, J.T.
          78:021-042

Mussalli, Y.G.
          78:088-007

Myers, J.M.
          78:03F-065

Myhre, D.L.
          78:02K-070

Nakano, Y.
          78:02F-004

Nakayama, F.5.
          78:03F-032
          78:03F-064

Nalluri, C.
          78:088-008

Narasimhan, T.N.
          78:02F-006
          78:048-012
          78:06A-009
Nash, K.G.
          78:05A-010
Nash, R.G.
          78:078-016

Nebgen, J.W.
          78:05G-063

Nelson, D.W.
          78:058-068
Nelson, M.C.
          78:050-058

Nelson, R.E.
          78:02K-028

Nelson, R.W.
          78:056-057
          78:058-058
          78:058-059
          78:058-060

Nelson, W.L.
          78:02A-001

Nelson, W.W.
          78:05A-004

Nettleton, W.D.
          78:02K-028

Neuman, S.P.
          78:048-012
New, L.L.
          78:026-025
Nicholaichuk, W.
          78:058-044

Nicholls, K.H.
          78:058-041

Nicholson, H.P.
          78:06A-003

Nielsen, N.E.
          78:021-012

Nielsen, R.L.
          78:06G-001

Nishita, H.
          78:050-001

Nissenbaum, A.
          78:02K-006

Nofziger, D.L.
          78:02G-075

Nordin, C.F.
          78:088-013

Norvell, W.A.
          78:078-012

Novais, R.
          78:02K-069

Obsemea, W.N.
          78:02K-043

Olness, A.E.
          78:050-037
Olosky, C.J.
          78:048-009

Olsen, S.R.
          78:073-014

Olson, B.R., Jr.
          78:03F-045

Olson, R.A.
          78:03F-019

On-Farm Irri. Committee
          78:068-005

Onesti, L.J.
          78:068-003

Onstad, C.A.
          78:02E-011

Oostermeyer, J.S.
          78:03F-067

Ortiz, N.V.
          78:02F-020
          78:048-002

Osteen, C.
          78:05G-058

Oster, J.D.
          78:050-044
Ou, L-T.
          78:058-027
Overcash, M.R.
          78:05A-017
          78:078-026

Paetzold, R.F.
          78:02G-040
          78:02K-062

Paily, P.P.
          78:058-015
Pall, R.
          78:020-059
Panu, U.S.
          78:02E-007

Papendick, R.
          78:02G-020

Parfitt, R.L.
          78:02K-030

Parlange, J.-Y.
          78:020-008

Parlange, J.Y.
          78:02G-019
          78:020-055
                                       297

-------
Parsons, B.L.
           78:02J-007

Partenheimer,  E.J.
           78:06B-011

Paterson,  E.
           78:02J-026

Patrick, W.H.
           78:02K-068

Patrick, W.H., Jr.
           78:02G-035
           78:02G-036
           78:02G-051
           78:02K-001
           78:02K-027

Patt, R.O.
           78:02F-005

Patterson, C.
           78:03F-074

Payne, M.L.
           78:03F-116
           78:03F-117

Payne, W.R.
           78:05A-020

Penkava, F.F.
           78:03F-070

Perkins, H.F.
           78:078-036

Peverly, J.H.
           78:058-046

Pfeiffer, G.H.
           78:05B-006

Philip, J.R.
           78:02G-012
           78:02G-043

Phillips, A.L.
           78:06A-006

Phillips, D.A.
           78:078-006

Phillips, D.W.
          78:020-002

Phillips, K.J.
          78:058-039

Phillips, N.A.
           78:05A-021

Phillips, R.E.
          78:02G-035
          78:026-036
          78:021-014
           78:02G-066
           78:021-019

 Piekielek, W.P.
           78:078-013
           78:078-024

 Pierson,  R.W.
           78:05G-067

 Piest, R.F.
           78:02J-011
           78:040-006

 Pietz, R.I.
           78:058-055

 Pitts, W.T.
           78:05G-073
Plate, H.
          78:05G-070
Pomareda, C.-
          78:03F-009

Ponce, S.L.
          78:058-038

Ponce, V.M.
          78:088-001

Popov, E.E.
          78:058-033

Poulovassilis, A.
          78:02G-080

Power, J.F.
          78:021-016

Prasad, K.G.
          78:078-036

Prather, R.J.
          78:05G-036

Pratt, P.F.
          78:03F-016
          78:050-042
          78:10A-001
Price, J.
          78:056-039
Price, J.D.
          78:058-024
          78:058-056

Pringle, J.C.
          78:058-048

Quisenberry, V.L.
          78:02G-066
Qureshi,  R.H.
           78:02K-045
           78:078-019

Raats, P.A.C.
           78:02G-077
           78:02G-078
           78:03F-110

Rachinskii, V.V.
           78:02G-056

Racz, G.J.
           78:02K-010
           78:02K-013

Radosevich, G.E.
           78:056-012
           78:05G-013
           78:05G-014
           78:050-015
           78:06E-001
Rahe, T.M.
          78:058-052
Rahman, M.
          78:02H-002

Raines, R.W.
          78:058-048

Rajagopal, R.
          78:05A-001

Ramig, R.E.
          78:021-008

Ramirez, J.M.
          78:021-006

Ramsey, M.K.
          78:026-083

Randall, G.W.
          78:05A-004

Rankin, J.M.
          78:078-030

Rao, P.S.C.
          78:026-013
          78:03F-013
          78:058-018

Rasmussen, V.P.
          78:021-025

Rasmussen, W.O.
          78:06A-014

Rasmussen, W.W.
          78:078-021

Rastogi, A.K.
          78:058-061
                                     298

-------
Rauschkolb,  R.S.
           78:05G-005

Ravelo, C.J.
           78:04B-008

Ravina, I.
           78:02K-008

Rawls, W.J.
           78:02E-011

Read, D.W.L.
           78:053-044

Reardon, E.J.
           78:02F-026

Rector, M.R.
           78:050-025

Reddell, D.L.
           78:02G-060
           78:04B-008
           78:058-067
Reddy, G.G.
          78:03F-022
Reddy, G.Y.
          78:053-003
Reddy, K.R.
Reed, W.
Reeve, R.
          78:026-035
          78:02G-036
          78:020-051
          78:02K-001
          78:05A-017
          78:06B-021
          78:073-008
Reeve, R.C.
          78:08A-002

Reginato, R.J.
          78:03F-112

Reichman, G.A.
          78:03F-125

Reicosky, D.C.
          78:021-020

Reizes, J.A.
          78:02J-017

Rendon-Herrero, 0.
          78:02J-004

Reneau, D.R.
          78:068-015
Replogle, J.A.
          78:03F-034
          78:073-011
          78:078-027

Reus s, J.O.
          78:021-022
          78:02K-023

Rhoades, E.D.
          78:05G-037

Rhoades, J.D.
          78:05G-036

Rhoads, F.M.
          78:03F-008
Rice, J.M.
          78:06E-013
Rice, R.C.
          78:02F-027

Richardson, C.
          78:053-023
          78:053-026

Richardson, C.W.
          78:04A-017
          78:053-024

Rickman, R.W.
          78:021-008
          78:073-005

Riggle, F.R.
          78:073-017

Richtmire, C.T.
          78:02K-056
Ring, L.
          78:03F-104
Ripken, J.F.
          78:088-009

Ritter, W.F.
          78:020-003
          78:053-037
          78:063-020

Rivers, E.D.
          78:02G-079

Roades, J.D.
          78:02G-010

Robbins, C.W.
          78:02G-039
          78:050-038

Robertson, W.K.
          78:021-017
Robillard, P.O.
          78:05G-060

Robinson, A.R.
          78:02J-011

Robinson, J.B.
          78:05A-016
          78:053-064

Robinson, S.C.
          78:03F-085

Robledo, E.
          78:021-036

Rodarte, L.
          78:02F-003
Rodger, N.
                                       78:03F-039
Rodi, W.
          78:05B-061
Rogers, P.
          78:06A-010

Rolston, D.E.
          78:02K-061
          78:03F-017
          78.-05A-009

Rosendahl, P.C.
          78:050-030
Ross, B.B.
Ross, R.
          78:02J-024
          78:08C-001
Rossman, L.A.
          78:050-031

Rothwell, D.F.
          78:053-027

Rouse, J.W.
          78:020-004

Routson, R.C.
          78:02G-022

Rumburg, C.B.
          78:03F-057
Rupar, B.
          78:03F-076
Russell, W.J.
          78:073-001
Russo, D.
          78:02G-034
                                        299

-------
Ryan, J.
          78:02K-003
Ryan, M.E.
          78:05G-043

Ryden, J.C.
          78:03P-010
          78:078-023

Sabey, M.B.
          78:05G-033

Sabol, G.V.
          78:086-013
Sagar, B.
Sain, P.
          78:02F-013
          78:02F-025
          78:05B-064
Saini, B.C.
          78:02G-076

Salazar, L.J.
          78:03F-020

Sammis, T.W.
          78:03F-026
          78:03F-063

San Valentin, G.O.
          78:021-017

Sanders/ T.G.
          78:05A-008

Sanghi, A.K.
          78:068-009

Sawhney, B.L.
          78:078-034
          78:06A-007

Sayegh, A.H.
          78:02K-003

Sayler, G.S.
          78:050006

Sayre, W.W.
          78:058-015

Scavia, D.
          78:05A-006

Schmugge, T.
          78:02G-031

Schneider, R.R.
          78.-05A-019
          78:05G-004
Schoenhofer, R.F.
          78:05G-062

Scholl, D.G.
          78:026-071

Schuman, G.E.
          78:058-008
          78:05G-076

Schwab, G.O.
          78:04B-009
          78:086-002

Scott, H.D.
          78:02G-040
          78:02K-062

Seginer, I.
          78:03F-092

Seitz, W.D,
          78:056-058
          78:06E-002

Sekhon, G.S.
          78:056-021

Selim, H.M.
          78:026-086
          78:058-018

Sepaskhah, A.R.
          78:026-029

Sethunathan, N.
          78:02K-049
          78:02K-053

Shalhevet, J.
          78:021-003
          78:030-004

Shanholtz, V.O.
          78:02J-024

Shannon, M.C.
          78:03C-001

Sharma, T.C.
          78:026-082

Sharon, S.
          78:02K-005

Sharp, B.M.H.
          78:06E-015

Sharpley, A.N.
          78:05A-011
Shaw, R.H.
          78:03F-021
Shearer, G.
          78:02K-066

Shearer, M.N.
          78:03F-081

Sheffield, L.F.
          78:068-007

Shen, H.T.
          78:058-013

Sherman, B.
          78:04A-007

Shimshi, D.
          78:021-026

Shipp, R.F.
          78:026-079

Shirk, K.S.
          78:02K-065

Shuman, L.M.
          78:02G-037

Siemer, E.G.
          78:03F-057

Simons, D.B.
          78:06A-015
          78:088-001

Simonson, G.H.
          78:058-004

Simpson, E.S.
          78:02A-005

Simpson, G.M.
          78:021-038
Sims, J.L.
          78:02K-027
Sinai, G.
          78:02A-004
Singer, A.
          7«:02K-007

Singer, M.J.
          78:040-004
Singh, B.
          78:056-021
                             Shayan,  A.
                                       78:02K-063
Singh, N.T.
          78:02K-036

Singh, P.N.
          78:086-003

Singh, S.S.
          78:02K-073
                                     300

-------
 Singh,  T.
          78:03F-006

 Singh,  V.P.
          78:04A-007

 Sinitsyna,  2.A.
          78:05B-031

 Sisneros, D.A.
          78:05B-048

 Sivakumar,  M.V.K.
          78:03F-021

 Siverts,  L.E.
          78:053-065

 Skaggs, R.W.
          78:02F-028
          78:02G-081
          78:04A-005
          78:048-007
          78:048-008
          78:048-009
          78;05G-018
          78:05G-034
          78:056-074

 Skjemstad,  J.O.
          78:078-008

 Skogerboe,  G.V.
          78:03F-031
          78:058-022
          78:05G-009
          78:05G-011
          78:05G-012
          78:05G-013
          78:050-014
          78:05G-015
          78.'10C-001

 Skryabin, G.K.
          78:02K-042

 Slack, D.C.
          78:078-017

 Sloss, J.M.
          78:04A-OQ2

 Smajstrla, A.G.
          78.-02G-060

 Smart, R.St.C.
          78:02K-030

 Smeck, N.E.
          78:02J-003
         78:058-007

Smika, D.E.
         78:05G-045
         78:050-077
Smiles,  D.E.
          78:026-007
          78:020-012
          78:020-043

Smith, C.N.
          78:040-003

Smith, D.V.
          78:068-019

Smith, J.H.
          78:05B-047

Smith, J.P.
          78:02J-008

Smith, M.S.
          78:02K-029

Smith, R.E.
          78:020-055

Smith, R.L.
          78:04C-001

Smith, S.J.
          78:02K-009
          78:02K-020
          78:02K-075
          78:058-025
          78:05G-037

Smith/ S.W.
          78:05G-009
          78:10C-001

Sneed, R.E.
          78:03F-075

Snyder, W.M.
          78:02E-002

Sochtig, H.
          78:078-003

Sokolov, M.S.
          78:058-034

Solomon, K.
         7a:03F-087
         78:03F-105
         78:03F-127
         78:088-004

Sommers, L.E.
         78t05B-068

Sotres, M.O.
         78:058-062

Spalding, R.F.
         78:05A-010

Spomer, R.G.
         78:040-006
 Sposito,  G.
          78:020-047
          78:020-053
          78:020-054

 Sprugel,  D.G.
          78:040-001

 Sprugel,  D.S.
          78:040-002

 Stammers, W.
          78:058-064

 Stanford, G.
          78:02K-074
          7S.-02K-075

 Starr, J.L.
          78:02G-008
          78.-02G-019

 steen, A.J,
          78:050-001

 Steenhuis/ T.S.
          78:058-036

 Stegman,  E.G.
          78:021-034

 Steinbach, G.E.
          78:03F-101

 Steinhardt, R.
          78:078-022

 Stewart,  C.E.
          78:050-022

 Stewart,  J.W.B.
          78:021-033
          78:02K-055

 Stierna, J.H.
          78:068-014

 Stolzy, L.H.
          78:020-045
          78:02G-046
          78:02K-057
          78:03F-015

 Stott, D.A.
          78:048-010

 Stout, W.L.
          78:078-004

 Strelkoff, T.
         78:03F-099

Streltsova, T.D.
         78:02F-012

Stringham, G.E.
         78:04D-008
                                     301

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Stuff, R.G.
         78:020-038

Stumpe, J.M.
         78:02K-040
         78:02F-023

Sudhakar-Barik
         78:02K-049
         78:02K-053

Sumayao, A.
         78:03F-062

Sumner, M.E.
         78:07B-030

Sunada, O.K.
         78:02F-020
         78:020-049
         78:048-002

Supak, J.R.
         78:02K-025

Sutherland, J.C.
         78:050-059

Sweeten, J.M.
         78:058-067

Swoboda, A.R.
         78:02K-025

Syers, J.K.
         78:05A-011

Szollosi-Nagy, A.
         78:02A-006

Tabatabai,  M.A.
         78:05A-005

Takamatsu,  T.
         78:02K-002

Takkar, P.N.
         78:03F-006
Tal, M.
         78:030005
Tandy, D.F.
         78:060-002
Tang, C.
         78:050-066
Tang, Y.K.
         78:02F-028

Tanji, K.K.
         78:03F-014

Tarasov, M.N.
         78:05B-032
Taverni, A.F.
         78:050-050

Taylor, A.G.
         78:05G-061

Taylor, C.R.
         78:068-015

Teague, W.R.
         78:050-039

Templer, O.W.
         78:06E-003

Terman, 0.L.
         78:020-032
         78:020-033
         78:021-007

Terry, D.L.
         78:02K-019

The Task Committee
         78:068-004

Theurer, J.C.
         78:03F-028

Thomas, A.W.
         78:078-025

Thomas, J.C.
         78:021-037
         78:05A-002

Thompson, D.B.
         78:05A-018

Thompson, T.
         78:03F-049

Thronson, R.E.
         78:050-019

Tiedemann, A.R.
         78:058-049

Tiedje, J.M.
         78:02K-029

Tillman, R.W.
         78:05A-011

Tinney, L.R.
         78:060-001

Todd, R.L.
         78:05A-021

Tomlinson, J.H.
         78:088-008

Touchton, J.T.
         78:02K-017
         78:02K-018
Toy, D.W.
         78:02K-061
Toy, T.J.
         78:078-033
Tribe, G.
         78:03F-082

Triplett, G.B., Jr.
         78:058-006

Trock, W.
         78:05G-012

Trock, W.L.
         78:05G-013
         78:05G-014
         78:050-015

Trotter, R.J.
         78:060-002

Troutman, B.M.
         78:04A-008
True, G.
         78:05G-026
Tryon, C.P.
         78:02J-007

Tscheschke, P.
         78:03F-049
         78:03F-060

Tubbs, L.J.
         78:068-017

Tucker, T.C.
         78:021-028
         78:021-029
         78:02K-038
         78:03F-018

Turner, A.K.
         78:02E-010

Turner, F.T.
         78:021-037
         78:058-056

Turner, T.R.
         78:03F-003

Udo, E.J.
         78:02K-035

Uehara, G.
         78:02K-039
         78:02K-060

Undan, R.C.
         78:06A-006

Unger, D.G.
         78:06E-020
                                        302

-------
Unger, P.W.
         78:03F-055

Unger, S.G.
         78:05G-051

Unny,  T.E.
         78:02E-007

Unrath, C.R.
         78:03F-075

Urguhart, N.S.
         78:073-015

Van Es, J.C.
         78:05G-055

Van Gils, J.B.H.M.
         78:026-085

Van Schilfgaarde, J.
         78:066-003

Vanderholm, D.H.
         78:056-061

Vanecek,  F.T.
         78:05G-031

Veerman,  G.J.
         78:026-085

Verasan,  V.
         78:021-019

Verge, M.J.
         78:048-011

Vetter, R.J.
         78:058-055

Virchenko,  E.P.
         78:058-031

Vitosh, M.L.
         78:03F-073

Vittal, N.
         78:088-002

Vittetoe, G.C.
         78:048-006

Vlachos,  E.G.
         78:056-012
         78:056-013
         78:056-014
         78:056-015

Vlek,  P.L.G.
         78:02K-031
         78:02K-040

Vocke, G.F.
         78:06E-021
         78:068-009
Waddell, T.E.
         78:056-047

Wadd.ington, D.V.
         78:03F-003

Wade, J.C.
         78:056-003

Wagenet, R.J.
         78:02K-024
         78:07A-003

Waite, T.D.
         78:056-030

Walker, M.E.
         78:02K-041

Walker, P.H.
         78:02J-018

Walker, P.N.
         78:086-003

Walker, W.
         78:068-019

Walker, W.R.
         78:03F-020
         78:058-022
         78:056-009
         78:056-010
         78:056-011
         78:06A-001
         78:100-001

Wall, 6.J.
         78.-02J-003

Wallace, A.
         78:02K-072

Walsh, L.M.
         78:03F-004
         78:03F-005
         78:078-002

Walter, M.F.
         78:058-036
         78:056-060
         78:056-071
Wang, J.
         78:026-031
Wann, S.S.
         78:02K-039
         78:02K-060

Ward, A.D.
         78:02J-009

Ward, K.J.
         78:078-005
Warrick, A.w.
         78:026-017
         78:026-041

Watanabe, F.S.
         78:078-014

Watson, K.K.
         78:026-003
         78:048-003

Watters, G.Z.
         78:088-005

Watts, D.
         78:03F-060

Watts, D.6.
         78:021-040
         78:03F-056
         78:056-045

Wauchope, R.D.
         78:100-003

Weaver, R.M.
         78:078-018

Weaver, R.W.
         78:058-050

Webb, S.N.
         78:048-003

Webber, M.D.
         78:02K-012

Weed, S.B.
         78:056-034
         78:056-074

Weeks, L.V.
         78:026-065

Weeks, W.W.
         78:021-017

Welch, L.F.
         78:02K-017
         78:02K-018

Wells, K.L.
         78:03F-027

Wells, L.G.
         78:026-081

Wendt, C.W. ..
         78:026-025

Wendte, L.W.
         78.-03F-124

West, D.W.
         78:021-002
                                      303

-------
Westerman, P.W.
         78:05A-017

Westerman, R. L.
         78:02K-038

Weston, R.F.
         78:05B-039

Wheaton, R.Z.
         78:05G-024

Wheeler, W.B.
         78:058-027
         78:05B-035

Whisler, F.D.
         78:020-003

White, E.L.
         78:060-002

White, G.B.
         78:068-011

White, J.G.
         78:03F-106

White, W.C.
         78:050-070

Whited, D.A.
         78:03F-001

Whitehead, W.R.
         78:048-013

Whiteley, H.R.
         78:058-064

Whittlesey, N.K.
         78:03F-011
         78:058-006
         78:06C-002

Wiedenfeld, R.P.
         78:02K-047
         78:050-001

Wierenga, P.J.
         78:020-006
         78:020-015

Wilding, L.P.
         78:02J-003

Wilke, O.C.
         78:020-025

Wilkinson, J.W.
         78:05A-006

Wilkinson, W.B.
         78:048-010

Willavize, S.
         78:021-010
Williams, J.R.
         78:040-005
         78:06A-008

Williams, R.E.
         78:050-048

Williams, T.H.
         78:020-003

Williamson, E.J.
         78:03F-113

Wilson, G.D.
         78:021-025
         78:021-040

Wilson, J.L.
         78:058-016

Wilson, R.G., Jr.
         78:058-029
Win, M.
         78:02E-010
Wineman, J.J.
         78:068-019

Winter, T.C.
         78:02F-015

Wit, K.E.
         78:020-085

Witherspoon, P.A.
         78:02F-006
         78:048-012
         78:06A-009

Witters, R.E.
         78:020-026

Wodzinski, R.S.
         78:050005
         78:03F-124

Wollum, A.G., II
         78:058-019

Wood, E.F.
         78:02A-006

Wood, J.D.
         78:020-014

Woodford, T.A.
         78:021-024

Woodriff, R.
         78:02K-059

Woodruff, J.M.
         78:021-011

Worstell, R.V.
         78:03F-115
Wright, D.L.
         78:021-011

Wright, J.L.
         78:020-007
         78:020-008
Wu, J.S.
         78:058-014
Yaron, D.
         78:03F-095
Yen, H.J.
         78:06A-004

Yermanos, D.M.
         78:021-015

Yoshida, T.
         78:02K-002

Youngs, E.G.
         78:020-067

Yukler, M.A.
         78:02A-003

Yule, D.F.
         78:020-062

Zachmann, D.W.
         78:020-064

Zanker, K.
         78:03F-041
         78:088-003

Zaradny, H.
         78:02G-002

Zhdamirov, G.G.
         78:058-033

Zibilske, L.M.
         78:058-050
         78:020-008
                                     304

-------
                                SECTION XLIII

                                SUBJECT-INDEX
Abstracts
          78:10C-002
          78:10C-006

Absorption
          78:020-012
          78:02G-043
          78:021-028
          78:02K-059

Acetylene Reduction
          78:05C-003

Acidic Soil
          78:02K-012
          78:02K-034
          78:05C-005
          78:07B-018
Acidity
Acids
          78.-05A-012
          78:02K-044
Activation Energy
          78:02K-037

Adoption of Practices
          78:03F-037

Adsorption
          78J02G-008
          78:02G-040
          78:02G-086
          78:02K-010
          78;02K-015
          78:02K-Q25
          78s02K-030
          78:02K-032
          78s02K-034
          78:02K-035
          78-.02K-036
          78s02K-051
          78.-02K-055
          78-.02K-063
          78:02K-064
          78:05B-005
          78:05B-016
          78:05B-028
          78:053-029
          78:056-036
          78:05B-042

Aeolian Soils
          78:02K-007
Aeration
          78:02K-Q52
          78:07B-030
          78:078-035
Aerobic Conditions
          7fi:02K-009
          78s02K-012

Aerobic Treatment
          78:02K-029
Aesthetics
          78:030-001
Aggregates
          78:02J-005
          78:04A-018

Agricultural Chemicals
          78:05B-026
          78:05C-002
          78:05G-019
          78:05G-037
          78:050-046
          78:05G-062
          78:050-064

Agricultural Damages
          78:05G-035

Agricultural Economics
          78:03F-096

Agricultural Engineering
          78:06E-005

Agricultural Runoff
          78:03F-106
          78:05A-011
          78:05A-016
          78:05A-018
          78:05A-019
          78:05A-020
          78:05B-023
          78:05B-026
          78:05B-068
          78:05G-034
          78:050-037
          78:056-064
          78:05G-065
          78:050-066
          78t05G-067
          78:056-072
          78:06B-017
          78:06B-020
          78:06E-013
          78:100-003

Agricultural Soils
          78:056-034

Agricultural Watersheds
          78:02A-004
          78:02J-015
          78:05A-019
          78:05B-037
           78:058-068
           78:05G-024
           78-.05G-046
           78:050-058
           78t05G-063
           78:050-065
           78:050-067
           78-.06A-008
           78:068-017

Agriculture
           78:03F-036
           78:03F-067
           78:03F-077
           78:03F-079
           78:03F-124
           78:05A-021
           78:058-067
           78rO50-003
           78:050-004
           78:05G-020
           78:050-051
           78:050-073
           78:050-074
           78:06A-013
           78:068-007
           78:068-021
           78:06D-001
           78:06E-009
           78:06E-021
           78:060-002
           78:060-003
           78:10C-005

Agronomic Crops
           78:03F-096
Air
           78s02G-011
           78:020-058
Air Entrainment
           78s02F-027
           78:020-073

Air Pollution
           78:02K-057
           78s03F-024
           78:040-007
           .78:05A-012
           78:058-054
           78:05C-005
           78:06B-021

Air Pollution Effects
           78:05C-005

Air Temperature
           78:020-006
           78:078-033

Air-water Interfaces
           78:08B-007
                                     305

-------
Air-water Interactions
          78:086-007
          78:08B-012
Albedo
Alcohols
Alfalfa
Algae
          78:03F-007
          78:03F-026
          78:03F-112
          78:05G-001
          78:021-006
          78:03F-096
          78:03F-125
          78:05G-007
          78:05G-044
          78:048-003
          78:056-007
          78:058-010
          78:05C-005
Algorithms
          78:02A-002
          78:02A-006
          78:02F-006

Aliphatic Amines
          78:05C-003

Alkali Metals
          78:02K-008

Alkali Soils
          78:05G-036

Alkaline Soils
          78:02G-010
          78:02G-023
          78:03F-006

Alkalinity
          78:05A-010

Alternative Costs
          78:05G-035
          78:068-010

Alternative Planning
          78:068-019
          78:06E-014
Aluminum
Amines
Ammonia
          78:02K-010
          78:02K-012
          78:078-018
          78:050-003
          78:02K-017
          78:02K-018
          78:02K-022
          78:02K-040
          78:02K-043
          78:03F-004
          78:03F-005
          78:050-003
          78:05G-066
          78:078-008

Ammonium Compounds
          78:020-037
          78:02K-001
          78:02K-003
          78:02K-004
          78:02K-005
          78:02K-013
          78:02K-017
          78:03F-057
          78:058-049
          78:05G-007

Ammonium Salts
          78:021-028

Ammonium Sulfate
          78:058-040

Anabaena Subcylindrica
          78:050-003

Anaerobic Conditions
          78:02G-035
          78:02K-029
          78:02K-068
Analysis
          78:02F-013
          78:078-018
Analytical Techniques
          78:02A-003
          78:02A-005
          78:02F-011
          78:02F-013
          78:02F-020
          78:02F-022
          78:02G-001
          78:02G-006
          78:026-015
          78:02G-027
          78:02G-041
          78:02G-068
          78:02K-045
          78:04A-007
          78:05A-006
          78:05A-015
          78:05A-019
          78:058-039
          78.-05G-004
          78:06A-010
          78:078-003
          78:078-019
          78:088-005
Anisotropy
Apples
          78:026-077
          78:03F-075
Application Equipment
          78:03F-071
          78:03F-072
          78:03F-076
          78:03F-085
          78:03F-086
          78:03F-114
          78:03F-117
          78.-03F-118

Application Methods
          78:03F-064
          78:03F-085
          78:03F-114
          78:05G-045
          78:050-070
          78:060-002

Appropriative Rights
          78:06E-007

Approximation Methods
          78:02F-023
          78:02F-024

Aquatic Environment
          78:058-030
          78:050-005
          78:050-006'

Aquatic Plants
          78:021-027

Aquatic Plant Control
          78:020-004

Aquatic Weed Control
          78:058-048

Aquatic Weeds
          78:020-004
          78:058-048

Aqueducts
          78:088-002

Aqueous Solutions
          78:026-008
          78:020-022
          78:02K-010
          78:02K-040

Aquifer Characteristics
          78:02F-006

Aquifer Management
          78:048-012
          78:06E-007

Aquifer Systems
          78:02F-022
          78:048-004

Aquifer Testing
          78:02F-027
Aquifers
          78:02A-003
          78:02F-003
          78:02F-007
          78:02F-008
          78:02F-009
          78:02F-012
                                      306

-------
Aquifers
    (cont.)
Aquitards
          78:02F-013
          78:02F-014
          78:02F-016
          78:02F-018
          78:02F-020
          78:02F-021
          78:04A-001
          78:048-010
          78:058-062
          78:08E-001
          78:02F-022
          78:02F-023
Arid Climates
          78:02K-038
          78:03F-041
Arid Lands
          78:05G-026
          78:07B-015
Arizona
          78:020-031
          78:040-007
          78:050-044
          78:078-011

Arsenic Compounds
          78:058-024

Arsenicals  (Pesticides)
          78:05A-002
          78:058-024

Artificial Recharge
          78:02K-056
          78:048-002
          78:048-010
Asia
          78:05G-020
Asphaltic Concrete
          78:080-001
Assay
          78:078-016
Assessments
          78:068-019

Atlantic Coastal Plain
          78:02K-048

Atmosphere
          78:058-041

Attenuation
          78:020-075
Australia
          78:02H-001
          78:048-003
Autoclaves
Automatic Control
          78:03F-068
          78:03F-115
          78:03F-116
          78:03F-128
          78:03F-130

Automation
          78:020-016
          78:03F-034
          78:03F-084
          78:03F-086
          78:03F-115
          78:03F-116
          78:03F-117
          78:03F-128
          78:03F-130
          78:078-003
          78:078-026

Automation Control
          78:03F-083

Backwater
          78:088-008

Backwater Profiles
          78:088-008

Bacteria
          78:03F-090
          78:058-004
          78:058-019
          78:05C-006

Bacteriophage
          78:058-005
Barley
          78:020-029
          78:021-014
          78:03F-027
          78:03F-096
          78:058-033
                              Basalts
                                        78:02K-007
                              Base Flow
                              Basins
Beans
Bed Load
          78:02K-033
          78:058-039
          78:078-026
          78:020-082
          78:03F-034
          78:06A-003
          78:068-003
          78:021-024
          78:021-028
          78:021-029
          78:02K-072
          78:058-043
          78:02J-013
          78:02J-017
          78:02J-018
          78s02J-028
Bed Material Load
          78:02J-013
Beds
Benefits
          78:02F-014
          78:02J-016
          78:03F-002
          78:03F-124
          78:050-004
Bentonite
          78:02K-073

Bermudagras s
          78:02K-020

Bibliographies
          78:10C-002
          78:10C-006
Bioassay
          78:05A-003
Biochemical Oxygen Demand
          78:058-010
          78:058-067
          78:050-031
          78:050-066

Bioindicators
          78:05B-004
Biomass
          78:05C-006
Bivariate Analysis
          78:08E-001

Border Irrigation
          78:03F-085
          78:03F-099
          78:03F-100

Boughton Model
          78:02F-011

Boundaries (Property)
          78:020-002

Boundaries (Surfaces)
          78:02F-004

Boundary Layer
          78:02F-010
          78:02F-014

Boundary Processes
          78.-02H-002

Bounding Wells
          78:048-013

Boussinesq's Equation
          78:02F-019

Box-Jenkins Models
          78:02E-009
                                     307

-------
  Breakwater
            76-.088-012
  Brines
            78:Q2G-065
  Broraegrass
  Bubbles
            78:021-033
            78-.03P-024
            78:02G-011
  Budapest (Hungary)
            79.-08E-001

  Bulk  Density
            78:020-075
 Buoyancy
 Burning
 Cabbage
 Cadmium
            78-.02H-001
            78:OSB-061
           7S.-03F-024
           78:03F-037
           78:056-040
           78:021-010
           78:021-022
           78:021-031
           78:021-032
           78;02K-002
           7S:02K-034
           78-.02K-058
           76:033-055

 Calcareous Soils
           78:02K-013
           7BJ02K-Q21
           78:02K-034
           78:078-010
           78:07B-OL4
           78:02K-045
           78:056-007
           78:02G-Q04
 Calcite
Calcium
           7S.-02K-003
           78:02K-024
           78:02K-035
           78:02K-047
           78:02K-058

Calcium Carbonate
Calcium Chloride
          78:05G-Q36

Calcium Sulfate
          78:02K-041
          78:05G-036
  Calibrations
            78:G2G-014
            78:076-035
                                                             Carriers
                               California
            78:02G-050
            78.-03C-C06
            78-.03P-079
            78:03F-080
            78:03P-084
            7S:G4B-001
            78:048-004
            76-.05A-012
            78:05G-016
            78.-05G-023
            78-.05G-025
            78:OfiD-001
            78:06E-007
  Canada
            78:02P-026
            78.-03F-070
            7Bs05B-041
            78:053-044

  Canal Lining
            78:04A-018

  Canal
 Canala
 Canopy
           78:06A-004
           78:0€A-005
           78:04A-018
           78:02J-025
           78:04A-017
 Capillary Action
           78:02G-043
           78:02G-Q64
           78t02G-068
           78:04B-002

 Capillary Plow
           78:048-002

 Capillary Water
           78s02G-038
 Capillary  Zone
           78:048-002

 Carbamate  Pesticides
           78:02K-Q25
Carbon
          89:02F-026
          7e:02K-038
          78.-05A-010
Carbon Dioxide
          78:02r-02€
          78-.02K-056
          73:053-027

Carbonate Rocks
          78:02P-Q26
                                                                       78r02G-026
                                                                       78:076-014
  Cation Adsorption
            78:02K-OCe
            7S:02K-024
            78:02K-026
            78:02K-039
            78{02K-058
            78:C2K-070
            78;07B-004

  Cation Exchange
            7fi:02G-037
            78-.02G-045
            78:02G-046
            78:021-021
            78s02K-003
            78sQ2K-024
            78-.02K-026
            78:02K-035
            76:02K-039
            78s02K-047
            78:02K-050
            78:02K-058
            78:02K-070
            78:05H-005
            78:05B-028
            78:078-004
                                         78:021-021
                               Cations
           78-.02K-047
           78:05G-042

 Center Pivot Systems
           79:
-------
Channels
          78:02F-019
          78:02J-014
          78:040-008
          78:05B-012
          78:06B-003
          78:088-003
          78:088-008

Chattahoochee River
   (Georgia)
          78:02E-003

Chelation
          78:078-012

Chemical Analysis
          78:02K-009
          78:02K-011
          78:02K-014
          78:02K-045
          78:02K-059
          78:02K-064
          78:02K-069
          78:02K-074
          78:02K-075
          78:05A-008
          78:05A-012
          78:058-003
          78:078-008
          78:078-014
          78:078-018
          78:078-019
          78:078-024
          78:078-028

Chemical Degradation
          78:02K-042
          78:05A-018
          78:058-029
          78:058-030

Chemical Oxygen Demand
          78:05A-018
          78:058-067

Chemical Potential
          78:02K-063

Chemical Precipitation
          78:020-045
          78:02G-046
          78:02K-015
          78:02K-052
          78:02K-065
          78:02K-073
          78:03C-003
          78:03F-050
          78:078-028

Chemical Properties
          78:02J-002
          78:02J-003
          78:02K-006
          78:02K-073

Chemical Reactions
          78:02K-009
          78:02K-047
          78:02K-065
Chemicals
          78:03F-114
Clogging
Chlorella Ellipsoidea
          78:05C-003
Chloride
Chlorides
          78:02K-071
          78:02K-010
          78:02K-064
          78:050-042

Chromatography
          78:020-056

Citrus Fruits
          78:03F-065
          78:03F-089

Civil Engineering
          78:09A-001

Classification
          78:068-003

Clay Loam
          78:058-005

Clay Minerals
          78:02K-007
          78:02K-012
          78:02K-025
          78:02K-050
       ,   78:02K-073
          78:058-028
Clays
Climates
          78:020-007
          78:020-010
          78:020-024
          78:020-075
          78:02J-001
          78:02J-002
          78:02K-050
          78:04A-012
          78:04A-018
          78:048-005
          78:040-002
          78:058-040
          78:060-002
Climatic Data
          78:02A-007
          78:02A-008
          78:02A-009
          78:020-005
          78:020-068
          78:020-074
          78:021-003
          78:021-005
          78:021-035
          78:03F-049
          78:03F-123
          78:078-033
Clovers
           78:03F-032
           78:03F-050
           78:03F-087
           78:03F-088
           78:03F-090
           78:058-033
           78:078-006
Coagulation
           78:050-038

Coal Mine Spoil
           78:020-071

Coal Mine Wastes
           78:021-024
COals
           78:068-004
Coastal Engineering
           78:088-012

Coastal Plain Soils
           78:050-034

Coastal Plains
           78:02K-041
           78:068-020
           78:078-036

Cohesive Soil
           78:02J-002
                             Coliforms
Colloids
Colorado
           78:05A-015
           78:058-004
           78:058-052
           78:050-066
           78:02K-039
           78:02K-060
           78:02K-031
           78:050-028
           78:078-012
           78:08A-001

Colorado River
           78:03C-006
           78:03F-032
           78:040-007
           78:050-022
           78:050-028
           78:050-035
           78:050-075
           78:06E-006

Colorado River Basin
           78:03C-006
           78:058-012
           78:058-038
                                      309

-------
 Colorado River Basin
     (cont.)
           78:05G-022
           78:050-028
           78.-05G-075
           78:06E-006
           78:07^-003

 Colorimetry
           78:076-003

 Columbia River
           78:06A-007
           78:06C-002

 Compacted Soils
           78:020024

 Compaction
           78.-02G-024

 Comparative Benefits
           78;03F-037

 Comparative Costs
           78:02J-007

 Coraparative Productivity
           78:03F-037

 Compressible Flow
          78:02P-009

 Computer  Models
          78.-02A-002
          78:02E-004
          76:02F-028
          78:02G-038
          78:02G-059
          78:02G-060
          78:02J-019
          78:02K-004
          78:02K-005
          78:03P-046
          78:03F-049
          78:03F-068
          78-.03F-101
          78:03F-102
          78:048-008
          78:043-011
          78:056-014
          78:05G~072
          78:06A-003
          78;06A-006
          78:06A-009
          78:06A-010
          78:06A-014
          78:06D-001

Computer Programs
          78:02G-057
          78:02J-009
          78:02J~017
          78:03F-046
          78:03F-049
          78:03F-058
          78.-03F-068
          78:03F-086
          78:03F-101
          78:03F-102
           78:03F-103
           78:04A-009
           78:04B-012
           78:04B-013
           78:050-039
           78:050-072
           78:06A-010
           78:076-021

 Conceptual Model
           78.-05G-033

 Concrete Structure
           78:08E-001
 Conduits
           78:088-008
 Conference
           78:05G-071
           78:10A-001

 Confined Water
           78:03F-110

 Connecticut River
           78:05A-009

 Conservation
           78:02J-021
           78:03F-10&
           78:05G-064
           78-.05G-071
           78:06G-002
           78:09C-001

 Constraints
           78:058-009

 Construction Costs
           78:0€A-006
           78:07B-027

 Consumptive  Use
           78:02D-003
           78:030-001
           78:03F-077
           78-.03F-109
           78J03F-118

 Contaminant  Arrival
  Distributions
           78:056-059

 Continuity Equation
           78:02G-053
           78.-04B-011

 Contour Farming
          78:02J-020

 Contour Furrowing
          78-.03F-059
Control
          78:05A-008
 Control Systems
            78:03F-068
            78:03F-115
            78:03F~116
            78:03F-117
            78:03F-118

 Convection
            78:02G-044
            78:02G-008
            78:02G-077
            78.-02G-078
            78:02K-062
            73:03F-056

 Conveyance  Structures
            78:03F-130
Cooling
            78.-03F-075
Cooling Levels
           78:05G-03L

Cooling Towers
           78:05C-001

Cooling Water
           78:04B-001
           78t05B-061
Copper
Core


Cores



Corn Belt
           78:021-032
           78:02K-002
           78.-02K-027
           78s02K-034
           7B:02K-072
78:02G-085
78:073-001
78.-07B-005
           78:05G-058
           78:066-007
Control Structures
          78;05G-024
Corn (Field)
           78.-02A-001
           78:0211-003
           78:02E-011
           73:02F-002
           78:026-032
           78:02G-033
           78:021-012
           78:021-018
           78:021-019
           78;Q2I-024
           78;02I-025
           78:021-032
           78:021-034
           78:021-040
           78:021-041
           78:021-042
           78.-03F-004
           78:03F-008
           78;03F-023
                                        310

-------
Corn  (Field)
    (cont.)
          78:03F-048
          78:03F-051
          78:03F-060
          78:03F-108
          78:03F-123
          78:03F-125
          78:04A-012
          78:05B-006
          78:058-055
          78:050-007
          78:05G-029
          78:05G-045
          78:07B-013
          78:07B-024

Correlation Analysis
          78:021-003
          78:021-005
          78:021-006
          78:021-012
          78:021-032
          78:068-003
          78:07B-013

Cost Allocation
          78:03F-101

Cost Analysis
          78:048-011
          78:068-007
          78:07B-011

Cost-Benefit Analysis
          78:05G-023
          78:068-010

Cost Comparisons
          78:02J-007
          78:02J-020
          78:03F-083
          78:03F-084
          78:068-010
          78:078-011
          78:08A-001

Cost-Effectiveness
          78:05G-010
Costs
Cotton
          78:02J-006
          78:03F-087
          78:03F-101
          78:05G-004
          78:050-033
          78:050-035
          78:06C-001
          78:06C-002
          78:021-003
          78:02J-012
          78:02K-005
          78:03F-047
          78:058-024
Cover Crop
          78:04A-017
Critical Days
         78:03F-095

Critical Flow
         78:078-001
         78:078-027
         78:088-002

Crop Pattern
         78:04A-003

Crop Production
         78:02A-001
         78:02G-029
         78:02G-033
         78:021-006
         78:021-018
         78:021-024
         78:021-025
         78:021-026
         78:021-028
         78:021-029
         78:021-030
         78:021-035
         78:021-036
         78:021-040
         78:03F-002
         78:03F-018
         78:03F-019
         78:03F-022
         78:03F-027
         78:03F-028
         78:03F-031
         78:03F-035
         78:03F-036
         '78.-03F-037
         78:03F-048
         78:03F-049
         78:03F-052
         78:03F-061
         78:03F-062
         78:03F-063
         78:03F-065
         78:03F-070
         78:03F-071
         78:03F-092
         78:03F-106
         78:03F-108
         78:03F-112
         78:04A-009
         78:04A-010
         78:048-005
         78:048-007
         78:048-008
         78:050-007
         78:05G-021
         78:050-023
         78:050-025
         78:050-076
         78:06A-013
         78:068-021
         78:060-002
         78:06E-021
         78:060-001
         78:078-024
         78:10C-005

Crop Response
         78:02F-002
Crops
           78:020-
           78:02G-
           78:02G-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:021-
           78:02K-
           78:03C-
           78:03C-
           78:03C-
           78:03F-
           78:03F-
           7 8:0 3F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:03F-
           78:048-
           78:058-
           78:05G-
           78:078-
           78:078-
•029
•032
•033
•005
•007
•010
•016
•018
•025
•026
•028
•034
•035
•042
•005
•002
•003
•004
•004
•006
•019
•023
•025
•027
•028
•031
•048
•055
•061
•062
•063
•095
096
005
•055
021
013
024
           78:02E-010
           78:020-031
           78:03F-009
           78:03F-113
           78:058-006
           78:060-001
           78:060-002
Cryogenics
           78:02C-001

Crystal Growth
           78.-02C-001

Crystalline Rocks
           78:02F-026

Cultural Control
           78:03F-002
           78:03F-080
           78:05G-024
Culverts
           78:088-002
Dairy Industry
           78:06A-016
           78:068-011
                                       311

-------
Dams
          78:02F-008
Danube River
          78:08E-001

Darcy-Weisbach Equation
          78:08B-005
          78:08B-010

Darcys Law
          78:02G-007
          78:02G-018
          78:02G-059
          78:088-012

Data Collections
          78:02J-021
          78:03F-039
          78:05B-001
          78:07B-013
          78:076-023
          78:078-028

Data Processing
          78:02J-010
          78;04D-001
          78:040-004
DDT
          78:058-033
Deaeration
          78:076-030

Decision Making
          78:04A-001
          78:050-031
          78:050-062
          78:06A-013
          78:06E-014
          78:06E-015

Decision Theory
          78:08E-001

Decomposing Organic Matter
          78:02K-022
          78:03F-023

Deficient Elements
          78:021-024

Deflection
          78:080-002
          78:080-003

Deformation
          78:06A-009

Degradation (Decomposition)
          78:02K-017
          78:058-056
Denitrification
         78:020-035
         78:020-036
         78:020-050
         78:02K-018
         78:02K-020
         78:02K-029
         78:02K-038
         78:02K-048
         78:02K-057
         78:02K-061
         78:02K-067
         78:02K-068
         78:02K-071
         78:03F-004
         78:03F-010
         78:03F-013
         78:03F-016
         78:03F-017
         78:03F-057
         78:05A-004
         78:05A-009
         78:058-018
         78:058-025
         78:058-043
         78:058-047
         78:058-064
         78:050-008
         78:050-034
         78:050-074
         78:050-077
         78:078-023

Deposition (Sediments)
         78:02J-026
Depth
         78:02F-021
         78:020-022
         78:02K-038
         78:04A-002
 Desalting
         78:050-010

 Desert  Plants
         7Bs02I-015
Deserts
         78:02K-038
Delaware
          78:020-003
          78:058-037
          78:068-020
Desiccants
         78:058-024

Design
         78:02J-009
         78:03E-093
         78:03F-098
         78:048-009
         78:078-015
         78:078-028
         78:088-010

Design Criteria
         78:02J-006
         78:03F-058
         78:03F-082
         78:03F-099
         78:03F-127
         78:08A-004
Design Data
          78:02J-028

Design Flow
          78:07A-002

Design Standards
          78:08A-004

Design Storm
          78:02E-002

Desorption
          78:020-003

Detention Reservoir
          78:02J-007
          78:02J-009
          78:06A-016
          78:08A-004
Diazinon
Dibron
Dicots
          78:05B-040
          78:058-040
                                                                     78:078-005
Diffusion
          78:020-004
          78:020-008
          78:020-035
          78:020-036
          78:020-040
          78:020-045
          78:020-060
          78:020-061
          78:02H-001
          78:021-002
          78:02J-014
          78:02K-026
          78:02K-036
          78:02K-061
          78:02K-062
          78:03F-056
          78:078-030
          78:078-035
          78:088-001

Diffusivity
          78:020-049
          78:020-059
          78:02H-002
          78:021-013
          78:021-021
          78:02K-036

Digital Computers
          78:02A-002

Dimensional Analysis
          78:020-082

Discharge
          78:08B.-009

Discharge Measurement
          78:048-009
                                      312

-------
Disease Resistance
          78:06G-001
 Distribution Systems
          78:03F-098
Diseases
          78:06G-001
Dispensing
          78:02E-003
Dispersion
Disposal
          78:02G-008
          78:02G-012
          78:02G-013
          78:02G-015
          78:02G-045
          78:02G-060
          78:02G-062
          78:02J-014
          78:02K-062
          78:056-013
          78:05B-016
          78:053-017
          78:058-061
          78:050-030
          78:088-013
          78:058-004
Dissolution
          78:02G-013

Dissolved Inorganic
   Phosphates
          78:05A-011

Dissolved Organic Carbon
          78:05A-010

Dissolved Oxygen
          78:05A-010
          78:058-010
          78:05B-065
          78:056-031

Dissolved Solids
          78:02G-013
          78:058-012

Distribution
          78:028-001
          78:02J-014
          78:03F-030
          78:03F-098
          78:03F-103
          78:03F-104
          78:03F-110
          78:068-005

Distribution (Patterns)
          78:02J-014
          78:03F-054
          78:03F-071
          78:03F-076
          78:03F-092
          78:03F-097
          78:03F-103
          78:03F-104
          78:03F-126
                              Ditches
                              Diurnal
          78:02F-019
          78:04A-002
          78:05G-011
          78:078-011
          78.-02F-021
          78:02G-031
          78:02K-043
          78:048-003

 Diversion
          78:02J-008
          78:04A-009

 Diversion Structures
          78:02J-008
Drag
         78:02J-017
Drainable Porosities
         78:02G-081

Drainage
         78:02G-003
         78.-02G-057
         78.-02G-058
         78:02G-077
         78:02G-078
         78:02G-081
         78:021-002
         78:02J-026
         78:030-006
         78:03F-040
         78:03F-044
         78:03F-096
         78:048-007
         78:048-008
         78:048-012
         78:040-001
         78:058-001
         78:058-021
         78s05G-023
         78:05G-025
         78:05G-026
         78:06A-006
         78:068-003
         78:06C-001
         78:06G-003
         78:078-022
         78:08A-002
         78:088-003
         78:08G-002
         78:080-003

Drainage Area
         78:05G-025

Drainage Control
         78:050-034

Drainage Density
         78:056-018
 Drainage Effects
           78:04A-015
           78:05G-002
           78:050-018
           78:05G-074
           78:06A-006

 Drainage Practices
           78:03C-006
           78:04A-015
           78:048-006
           78:048-008
           78:08A-002

 Drainage Problems
           78:050-023

 Drainage Programs
           78:03C-006

 Drainage Systems
           78:048-007
           78:048-008
           78:05G-018

 Drainage Water
           78:026-039
           78:02K-052
           78:04C-001
           78:058-046
           78:05G-018
           78:056-020
           78:050-044
           78:05G-074
Drains
          78:02F-028
          78:03F-124
          78:04A-002
          78:04A-005
          78:088-003
Drawdown
          78:02A-003
          78:02F-003
          78:02F-009
          78:02F-012
          78:02F-016
          78:02F-018
          78.-02F-027
          78:04A-005
          78:.04B-009

Drifting (Aquatic)
          78:050-001
Drilling
          78:050-025
Drops (Fluids)
          78:03F-071

Drought Resistance
          78:03F-047

Drought Tolerance
          78:021-015
                             Droughts
                                                                    78:02A-002
                                     313

-------
Dry Farming
          78:021-008
          78:04A-010

Drying
          78:02G-030
          78:020-067
          78:020-080
          78:02G-084
          78:07B-017

Drying Curves
          78:026-063
Dust
          78:040-007
Dye Releases
          78:02E-003

Dynamic Programming
          78:03F-101
Dynamics
          78:02G-056
          78:026-074
          78:08B-001
Earth Dams
Ecology
          78:02F-008
          78:02K-023
          78:05B-054
          78:06G-002
Economic Analysis
          78:03F-009
          78:06B-002

Economic Efficiency
          78:03F-022
          78:04A-003
          78:04A-004
          78:05G-031
          78:05G-035

Economic  Feasibility
          78:02J-020
          78:03F-066
          78:048-005
          78:05G-047

Economic Impact
          78:02J-020
          78.-05G-016
          78:050-035
          78.-05G-058
          78:056-075
          78:06A-007
          78:063-007
          78:063-011
          78:068-012
          78:063-014
          78:063-015
          78:068-021
          78:06E-015
          78:066-002
Economic Justification
         78.-02F-022
         78:04A-010

Economic Prediction
         78:068-001
         78:068-007
         78:068-009
         78:068-021

Economics
         78:03F-037
         78:03F-092
         78:03F-108
         78:03F-124
         78:060001
         78:06E-002
         78:06E-021

Economies of Scale
         78:058-009

Ecosystems
         78:02K-011
         78:06A-002
         78:06A-014
         78:078-016

Edge Effects
         78:026-005
Education
Effects
         78:09A-001
         78:04A-001
         78:056-033
Efficiencies
         78:03F-038
         78:03F-082
         78:068-005
         78:08C-001

Efficiency
         78:03F-020
Effluents
         78:02K-015
         78:03F-015
         78:058-021
         78:058-061
         78:050007
Eggplant
         78:058-040

Electric Power Costs
         78:03F-052
         78:080001

Electric Power Demand
         78:03F-069

Electric Power Rates
         78:080001

Electrical Conductance
         78:026-010
         78:026-014
          78:02G-030

Electrical Resistance
          78:078-030
          78:078-035

Electrodes
          78:02K-002
          78:07B-030

Electronic Equipment
          78:03F-115
          78:03F-116
          78:03F-117
          78:03F-118
          78:083-009

Elements (Chemical)
          78:021-032
          78:02K-006
          78:078-019

Emerging Vegetation Stage
          78:026-029

Energy
          78:03F-067
          78:03F-086
          78:03F-113
          78:048-014
          78:068-004
          78:060002

Energy Conversion
          78:03F-066
          78:03F-067
          78:03F-086

Energy Budget
          78:03F-007

Energy Conservation
          78:026-059

Energy Costs
          78:080001

Energy Dissipation
          78.-02J-028

Energy Gradient
          78:08B-006

Energy Loss
          78:03F-034
          78:088-006

Engineering
          78:09A-001

Engineering Education
          78.-09A-001

Engineering Structures
          78:08A-001

Entrainment
          78:088-012
                                       314

-------
Environment
           78:02K-066
           78:058-050
           78:06E-021

Environmental Control
           78:02K-042
           78:05G-051
           78:068-010
           78:06E-011

Environmental Effects
           78:02A-006
           78:021-033
           78:02J-011
           78:046-004
           78:058-011
           78:058-033
           78:058-055
           78:058-057
           78:058-058
           78:058-059
           78:058-060
           78:05C-001
           78:050-002
           78:06A-002
           78:06A-003
           78:068-001
           78:06B-014
           78:06G-003

Environmental Sanitation
           78:02K-071
           78:05G-051
           78:05G-070
Equations
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
:02A-011
:02E-010
:02F-001
:02F-003
:02F-004
:02F-006
:02F-007
:02F-010
.-02F-012
:02F-016
.-02F-018
:02F-019
:02F-028
:02G-001
:02G-002
:02G-004
:02G-006
:02G-018
:02G-022
:02G-024
:02G-041
:02G-042
:02G-048
:02G-055
:02G-061
:02G-073
:02J-013
:03F-095
:04A-002
.-058-017
:05B-057
:05B-058
:05G-031
: 088-007
 Equilibrium
           78:02K-047

 Equipment
           78:02G-011
           78:02G-014
           78:03F-039
           78:05G-026
           78:06C-001
           78:078-011
           78:078-015
           78:08A-001

 Erodibility
           78:02J-001

 Erosion
           78:02G-013
           78.-02J-001
           78:02J-002
           78:02J-007
           78:02J-012
           78.-02J-015
           78:02J-021
           78:02J-024
           78:02J-027
           78:04A-013
           78:04A-017
           78:040-001
           78:040-004
           78:040-005
           78:040-006
           78:040-008
           78:058-003
           78:058-036

Erosion Control
           78:021-011
           78:02J-006
           78:02J-020
           78:02J-021
           78:040-004
           7.8:05G-048
           78:05G-058
           78:068-011
           78:068-012
           78:068-015

Erosion Rates
           78:02J-001
           78:02J-002

Estimating Equations
           78:020-006
           78:02G-034
           78:02G-072
           78:02G-082
           78:02G-083
           78:03F-126
           78:078-033
Estimating
          78:020-003
          78:02E-001
          78:02E-005
          78:02E-011
          78:02G-065
          78:02G-082
          78:030-001
          78:03F-095

          315
                                               Ethers
                                                         78:058-031
                                                         78:058-033
                                                         78:05C-002
                                                         78:05G-035
                                                         78:05G-063
                                                         78:078-013
                                                         78:088-011
                                                         78:05G-001
Eutrophication
          78:02K-032
          78:058-007
          78:05C-006
          78:05C-007
          78:05G-008
          78:05G-067

Evaluation
          78:03F-091
          78:03F-099
          78:03F-104
          78:05A-015
          78:058-014
          78:068-019
          78:09A-001

Evaporation
          78:020-002
          78:020-017
          78:020-021
          78:021-003
          78:038-001
          78:03F-007
          78:03F-081
          78:03F-097
          78:03F-112
          78:03F-118
          78:058-033

Evapotranspiration
          78:02A-008
          78:02A-010
          78:02A-011
          78:020-003
          78:020-004
          78:020-005
          78:020-007
          78:020-008
          78:02F-018
          78:02G-038
          78:021-003
          78:021-004
          78:021-006
          78:021-025
          78:021-034
          78:021-036
          78:021-037
          78:021-042
          78:03F-007
          78:03F-026
          78:03F-031
          78:03F-033
          78:03F-048
          78:03F-049
          78:03F-079
          78:03F-109
          78:03F-123
          78:050-044
          78:068-009

-------
Excess Water
          78:03F-096

Excessive Precipitation
          78:02A-005

Expansive Soils
          78:02J-002

Failure (Mechanics)
          78:08E-001
          78:08G-002
          78:08G-003

Fallowing
          78:03B-001
          78:03F-055
          78:04A-012
          78:058-044

Farm Equipment
          78:04B-014

Farm Management
          78.-03F-124
          78:056-001
          78:058-006
          78:05G-060

Farm Wastes
          78:02F-002
          78:058-040
          78:058-067

Feasibility Studies
          78:048-011

Feature Prediction Model
          78:02E-007

Federal Government
          78:06E-020

Federal Project Policy
          78:06E-011
          78:06E-020

Federal Water Pollution
   Control
          78:056-071
          78:06E-010
          78.-06E-020

Feed Barley
          78:03F-096
Feed Lots
          78:05A-016
          78:05C-003
          78.-05G-076
Feeds
          78.-03F-113
Fertility
          78:03F-003

Fertilization
          78:020-051
          78:021-005
         78:021-006
         78:021-016
         78:021-026
         78:021-030
         78:02K-001
         78:02K-004
         78:02K-005
         78:02K-036
         78:02K-040
         78:02K-043
         78-.02K-057
         78:03F-001
         78:03F-002
         78:03F-003
         78-.03F-006
         78:03F-012
         78:03F-015
         78:03F-017
         78:03F-024
         78:03F-061
         78.-03F-065
         78:03F-073
         78:03F-114
         78:058-020
         78:058-043
         78:058-044
         78:05B-046
         78:058-049
         78:05G-005
         78:056-029
         78:050-039
         78:078-013
         78:078-023
         78i07B-024
         78:10C-002

Fertilizers
         78:02F-002
         78:02G-032
         78:020-033
         78:021-007
         78:021-009
         78:021-017
         78:021-022
         78:02K-001
         78:02K-009
         78:02K-013
         78:02K-017
         78:02K-018
         78:02K-019
         78.-02K-020
         78:02K-021
         78:02K-031
         78:02K-063
         78.-02K-066
         78:02K-069
         78:03F-004
         78:03F-005
         78:03F-008
         78:03F-018
         78:03F-019
         78:03F-025
         78:03F-036
         78:03F-052
         78:03F-057
         78:03F-059
         78s03F-067
         78:03F-114
         78:048-014
         78.-04D-003

        316
          78:058-001
          78:058-025
          78:058-040
          78:05G-007
          78.-05G-021
          78:05G-037
          78-.05G-070
          78:05G-077
          78:068-012
          78:06E-021
          78:078-012
          78:100001
Fescues
          78:021-007
          78:03F-024
          78:078-009

Field Capacity
          78.-02G-038
          78:02G-079
Filters
          78:04A-005
Filtration
          78:02J-022
          78.-03F-032
          78:03F-045
Financing
          78:05G-023

Finite Element Analysis
          78:02G-048
          78:02F-019
          78:02F-022
          78-.02F-024
          78:02P-025
          78:02G-057
          78:02G-059
          78:02J-024
          78:048-011
          78:048-012

Fissures (Geologic)
          78:02F-012

Flexible-Flap Drain
   Valves
          78:088-003

Flexibility
          78:03F-084
                                                           Float Plan
Floats
          78:020-004
          78:03F-053
Flocculation
          78:05G-038

Flood Discharge  .
          78:02A-009

Flood Irrigation
          78:02G-051
          78:021-037
          78:02K-001

-------
Flood Irrigation
    (cont.)
           78:053-002
           78:058-047

Flood Routing
           78-.02J-024
Flooding
Floods
Florida
Flow
          78:02G-035
          78:020-036
          78:02K-027
          78:02K-049
          78:02K-053
          78:03F-040
          78:03F-057
          78:02E-002
          78:021-027
          78:02K-070
          78:03F-065
          78:02E-010
          78:02F-003
          78:02F-009
          78:02F-010
          78:02F-012
          78:02F-013
          78:02F-Q14
          78:02G-002
          78:02G-007
          78.-02G-009
          78:020-013
          78:08B-003
          78:08B-008

Flow Around Objects
          78:02F-025

Flow Characteristics
          78:02G-078
          78:02J-016
          78:088-002

Flow Control
          78:03F-053
          78:03F-059
          78:083-007

Flow Duration
          78:07B-026

Flow Friction
          78:088-010

Flow Measurement
          78:07B-011
          78:07B-027
          78:086-009

Flow Nets
          78:058-062

Flow Profiles
          78:088-008
Flow Rates
          78:021-004
          78:02J-019
          78:03F-064
          78-.03F-093
          78.-03F-100
          78:03F-102
          78:043-006
          78-.05B-062
          78:06A-005
          78:08B-004
          78:088-006

Flow Resistance
          78:021-004

Flow System
          78:02G-078

Fluid Flow
          78:05B-061

Fluid Infiltration
          78:058-022

Fluid Mechanics
          78:02G-053

Flumes
          78:078-011
          78:07B-027
          78:08B-009

Fluorometry
          78:078-018

Flushing
          78:025-011

Fluvial Sediments
         78:02J-003
Fly Ash
Foliar
         78:021-024
         78:05G-029
Foliar Application
         78:05G-029

Forage Grasses
         78:021-016
         78:078-009

Forage Sorghum
         78:02K-021

Forecasting
         78:02A-006
         78:02E-005
         78:02F-011
         78:06A-008

Forest Fires
         78:058-049

Forest Management
         78:056-065
         78:056-047
         78:050-051
        317
           78:05G-069
           78:06A-014
           78:06A-015

Forest  Soils
           78:05A-012

Forest  Watersheds
           78:02A-011
           78:05A-021
           78:058-065
           78:056-069
Forestry
          78:06A-014
Fossil Fuels
          78:021-024

Fourier Analysis
          78:02G-044

Fractional Gaussian
   Noise Algorithms
          78:02E-004

Free Surfaces
          78:04A-002
          78:083-007
Freezing
          78:02C-001
          78:02G-020
          78t02G-025
          78:03F-074
          78:03F-075
Frequency
          78:048-003

Frequence Analysis
          78:05G-065

Frequency Curves
          78:03F~064

Frost Heaving
          73:02C-001
          78:078-022

Frost Protection
          78:03F-074
          78:03F-075

Froude Number
          78:058-061

Frozen Soils
          78:02G-020
          78:02G-025

Fruit Crops
          78:03F-075
          78:03F-080

Fumigants
          78:056-054

Furrow Irrigation
          78:02G-083
          78:03F-054

-------
 Furrow Irrigation
    (cont.)
           78:03F-059
           78:03F-080
           78.-03F-085
           78.-03F-115
           78:03F-117
           78:04D-008
           78:073-021
 Grading
 Furrows
 Gages
           78:02G-083
           78:078-015
Gamma Rays
           78:02G-016
           78:02G-075

Gamma Scanning System
           78.-02C-001

Gas  Chromatography
           78:05B-048
           78:073-023
Gas Flux
Gases
          78:05A-009
          78:063-004
Geochemistry
          78:02F-026
          78:02K-006

Geometric Mean
          78:05A-015

Geomorphology
          78:063-003
Geophysics
Georgia
          78:02E-009
          78:02F-021
          78:02E-003
           78:040-007
           78.-05G-026
 Gradually Varied  Flow
           78:088-008

 Grain Sorghum
           78:03F-047
           78:03F-055
           78:04A-017

 Grains (Crops)
           78:02E-011
           78:021-005
           78:03F-022

 Grand Traverse Bay  Region
           78:05A-001
 Granules
           78.-02G-026
           78.-02K-041
           78:08B-012
Grapefruit
          78:021-003
          78:03C-004

Graphical Analysis
          78:02G-022
          78:02J-004

Graphical Methods
          78:02J-004
          78:03F-100
          78:083-002
          78:088-005
Grasses
Gravels
          78:021-011
          78:02J-022
          78:03P-024
          78:02G-021
          78:04A-018
Geothermal Studies
          78:043-001

Germination
          78:02G-029
          78:021-011

Glacial Lake Souris Basin
          78:026-079

Golf Courses
          78:05A-002
          78:053-011
Gravimetric Analysis
          78:073-022
          78:078-034

Gravitational Water
          78.-02G-049
Grazing
          78.-04A-006
          78:05G-019
Graded
           78:02J-006
Gradient Search Procedure
          78:056-031
Great Lakes
          78:020-002
          78:05A-016
          78:05G-046
          78:05G-067

Great Plains
          78:021-006
          78:06B-007
 Greenhouses
           78.-02G-032
           78.-02G-033
           78:026-037
           78:021-043
           78:078-014

 Groundwater
           78:02A-003
           78:02A-008
           78:02A-010
           78:02F-003
           78:02F-005
           78:02F-008
           78:02F-009
           78:02F-010
           78:02F-012
           78.-02F-014
           78.-02F-016
           78.-02F-019
           78:02F-020
           78:02F-021
           78:02F-024
           78:02F-026
           78:02F-027
           78:02K-048
           78:04A-005
           78:043-003
           78:04B-006
           78:043-010
           78:05A-001
           78:05A-010
           78:058-016
           78:053-017
           78:058-035
           78:053-039
           78:053-047
           78:053-052
           78:053-057
           78:053-058
           78:056-016
           78:05G-028
           78:05G-045
           78:056-076
           78:05G-077
           78:063-009
           78:065-003
           78:06E-007
           78:08A-002
           78;08B-003
           78.-08E-001
           78:10C-002
           78tlOC-005

Groundwater Basins
           78:043-004
           78:048-011
           78:06D-001

Groundwater Contamination
           78:05B-060

Groundwater Mounds
           78:02F-001
           78:043-002

Groundwater Movement
           78:02A-003
           78.-02F-004
                                       318

-------
 Groundwater Movement
    (cont.)
           78:02F-006
           78:02F-007
           78:02F-008
           78:02F-009
           78:02F-010
           78:02F-012
           78:02F-014
           78:02F-015
           78.-02F-016
           78:02F-018
           78:02F-022
           78:02F-023
           78:02F-024
           78:02F-025
           78:02F-028
           78:02G-019
           78:04A-002
           78:048-011
           78:046-012
           78:048-013
           78:058-016
           78:058-017
           78:058-039
           78:058-057
           78:058-058
           78:058-059
           78:058-060

 Groundwater Quality
           78:058-039

 Groundwater Recharge
           78:02F-001
           78:02F-005
           78:02K-056
           78:048-002
           78:048-003
           78:058-059
           78:058-060
           78:06E-003
           78:10C-002

Groundwater Resources
           78:058-059
          78:058-060
          78:068-004

Growth Chambers
          78:021-002
          78:021-014
          78:021-033

Growth Rates
          78:03F-021

Growth Stages
          78:020-003
          78:021-001
          78:021-025
          78:021-026
          78:021-034
          78:021-036
          78:021-040
          78:021-041
          78:021-042
          78:030-002
          78.-03F-031
          78:03F-033
 Guam
 Gullies
           78:03F-048
           78:03F-051
           78:068-009
           78:078-007
           78:058-040
           78:02J-011
           78:04A-009
           78:058-012

 Gully Erosion
           78:02J-011
           78:04D-006
 Gypsum
 Hardwood
           78:02G-013
           78:02K-003
           78:02K-028
           78:02K-041
           78:03F-006
           78:05G-036
           78:02A-011
Harp  Lake
Hay
           78:058-041
          78:021-016
          78:03F-057
Hazen-Williams Equation
          78:088-005
          78:088-006
          78:088-010
Head Loss
          78:02F-028
          78:088-005
Heat Flow
          78:02G-020
Heat Flux
          78:02H-002

Heat Transfer
          78:020-001
          78:058-061

Heated Water
          78:053-015

Heavy Metals
          78:021-022
          78:021-032
          78:02J-003
          78:02K-002
          78:02K-034
          78:05A-005
          78s05B-055
Herbicides
          78:02K-016
          78:02K-042
          78:02K-062
           78:03F-036
           78:040-003
           78:058-006
           78:058-023
           78:058-026
           78:058-027
           78:058-034
           78:058-035
           78:058-048
           78:10C-003

 Heterogeneity
           78:02G-053
           78:02J-005

 Highway Beautification
           78:021-011

 Highway Effects
           78:04C-001
 History
           78:088-009
 Homogeneity
           78:02J-005

 Horizontal Infiltration
           78:02G-034

 Hudson  River
           78:05G-050

 Humic Acids
           78:02K-002

 Humid Areas
           78:03F-078
           78.-03F-089
           78:048-007

 Humid Climates
           78:020-003
           78:03F-065
           78:03F-073
           78:03F-078
           78:048-007
Humidity
Hungary
          78:020-006
          78:08E-001
Hurst Coefficient
          78:02E-004

Hydration
          78:02K-008

Hydraulic Conductivity
          78:02A-003
          78:02F-001
          78:02F-007
          78:02F-016
          78:02F-017
          78:02F-023
          78:02F-028
          78:02G-010
          78:02G-018
                                        319

-------
  Hydraulic Conductivity
     (cont.)
            78.-02G-024
            78-.02G-028
            78.-02G-034
            78:02G-042
            78:020-044
            78:02G-049
            78:02G-054
            78:02G-055
            78:02G-057
            78:02G-061
            78:02G-064
            78:02G-073
            78:02G-084
            78.-02G-085
            78:021-008
            78:02J-019
            78:030003
            78:03F-093
            78:03F-110
            78.-04A-018
           78:048-009
           78.-07B-036
           78:088-012

 Hydraulic Conduits
           78:088-010

 Hydraulic Design
           78:088-002

 Hydraulic Equipment
           78:078-001

 Hydraulic Gradient
           78:02F-007

 Hydraulic Models
           78:088-004

 Hydraulic Properties
           78:020-073
           78:088-004
           78:083-005

 Hydraulic Valves
           78:088-003

 Hydraulics
           78:02E-003
           78:02J-013
           78:05B-013
           78:088-007
          78:088-008
          78:088-011
          78:088-012

Hydrodynamics
          78:020-015
          78;04A-007
          78.-06A-004

Hydroelectric Power
          78:06A-007

Hydrogen Ion Concentration
          78:02K-010
          78:02K-043
          78:02K-044
          78.-02K-051
          78:058-042
            78:05G-001

  Hydrogeology
            78:02F-015

  Hydrographs
            78:02A-005
            78.-02J-012
            78:04A-006
            78:078-032

  Hydrologic
            78:02A-011

  Hydrologic Aspects
            78.-02J-009
           78:04A-006
           78:05A-020
           78:068-004

  Hydrologic Budget
           78:020-002
           78:036-001
           78:03F-026
           78:050-072

 Hydrologic Cycle
           78:02A-010
           78.-02A-011

 Hydrologic Data
           78:02E-007
           78:02F-011

 Hydrologic Properties
           78:02A-010
           78:020-060
           78:078-036

 Hydrological Extremes
           78:02E-001
 Hydrology
           78:02A-004
           78:02A-005
           78:02A-010
           78:020-001
           78:02E-004
           78:02E-007
           78:02E-008
           78:02E-009
           78:02F-014
           78:02F-019
           78:020-055
           78:05B-059
           78:058-060
           78:068-004
Hydrolysis
          78:02K-053
          78:02K-074
          78:03F-029
          78:058-029
Hydrometry
          78:08B-009
Hysteresis
                                    320
          78:02G-003
          78:020-063
          78:02G-067
 Ice
 Idaho
 Illinois
 Illite
            78:02G-080
            78.-02K-037
           78:02H-002
           78:02J-008
           78:02J-010
           78:02J-015
           78:03F-036
           78i03F-052
           78:03F-107
           78:05C-006
           78:07A-001
           78:058-001
           78:05G-061
           78:02J-002
           78:02K-025
 Imperial Valley
           78:048-001

 Impermeable Beds
           78:02F-014

 Impervious Soils
           78:02F-010
           78:02F-014

 Improvement
           78:050-033
 Income
           78:03F-096
 Incubation
Indiana
           78:020-035
           78:02G-051
           78:02K-014
          78:02A-001
          78:02K-070
          78:058-068
Indicators
          78:03F-021

Industrial Plants
          78:05B-055

Industrial Wastes
          78:02K-011
          78.-05C-002

Infiltration
          78:02A-007
          78.-02A-009
          78:02D-005
          78j02F-001
          78:02G-001
          78:020-005
          78:020-009
          78:020-015
          78:020-019
          78:020-021

-------
 Infiltration
     (cont.)
           78:02G-023
           78:02G-027
           78:02G-028
           78:02G-034
           78:02G-041
           78:02G-043
           78:02G-044
           78:02G-048
           78:02G-052
           78:02G-055
           78.-02G-058
           78:020-059
           78:02G-061
           78:02G-064
           78.-02G-067
           78:02G-068
           78:02G-072
           78:02G-073
           /H:02G-075
           78:02G-082
           78:02G-083
           78:02G-085
           78:026-086
           78:03F-037
           78:03F-054
           78:03F-093
           78:03F-100
           78.-03F-110
           78:04A-006
           78:04A-007
           78:048-012
           78:05G-001
           78:07B-021

 Infiltration Models
           78:02G-055

 Infiltration Rates
           78:02G-055
           78:02G-058
           78:02G-059
           78:02G-067
           78:020-072
           78:02G-083
           78:03F-037
           78:03F-099
          78:04A-006
          78:076-021

Infiltrometer
          78:02G-005
          78:073-021
Inflow
          78:04A-008
Infrared Radiation
          78:02F-021
Inhibitors
          78:02K-017
          78:02K-018
          78:02K-022
          78:02K-029
          78:03F-004
          78:03F-005
          78.-03F-029
          78:05A-005
          78:058-011
          78:078-002
          78:078-003

 Initial Temperature
          78:02H-002

 Injection'  .
          78:03F-114

 Injection Wells
          78:048-013

 Inorganic Compounds
          78:02K-006
          78:02K-014
          78:02K-015
          78:02K-022

 Input-Output Analysis
          78:02A-006
          78:056-035

 Insecticides
          78:02K-025
          78:10C-003

 Installation
          78:03F-043
          78:048-006
          78:05G-026
          78:060-001
          78:08A-002
          78:08G-002
          78:08G-003

 Institutional  Constraints
          78:05G-047
          78:068-012
          78:06E-015
          78:06G-003

 Institutions
          78:06A-007

 Instrumentation
          78:02G-005
          78:02G-011
         78:02G-014
         78:020-016
         78:026-062
         78.-02J-001
         78:03F-115
         78:03F-116
         78:03F-117
         78:078-015
         78:078-030
         78:078-032
         78:08A-001
         78:088-009
 Intermittent Streams
           78:078-032

 International Field Year
           78:02D-002

 Investment
           78:06C-001

 Ion Exchange
           78:026-065
           78:021-023
           78:02K-010
           78:02K-060

 Ion Transport
           78:02G-065
           78:02K-060
           78:02K-064
           78:056-039
           78:078-026
 Ions
 Iowa
           78:02K-008
           78:03C-005
           78:03F-021
           78:03F-108
           78:040-006
           78:058-008
           78:068-012
Iron
                              Intakes
         78:026-083
Integrated-Finite-
   Difference Method
         78:02F-006

Interception
         78:06A-004
         78:06A-005

         321
          78:021-027
          78:02K-027
          78:02K-052
          78:02K-072
          78:078-019

Iron Oxides
          78:02K-010
          78.-02K-030
          78:02K-051
          78:05D-001

Irradiation
          78:078-009

Irrigated Agriculture
          78:03F-009

Irrigated Land
          78:026-039
          78:03F-014
          78:03F-016
          78:03F-042
          78:03F-098
          78:056-005
          78:056-012
          78:056-013
          78:056-014
          78:05G-015
          78:056-026
          78:06A-004
          78:068-007
          78.-06E-001
          78:06E-003
          78:066-001
          78:066-003
          78:10A-001
          78:10C-001

-------
Irrigation
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78s
          78:
          78;
          78;
          78:
          78:
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
           78:
           78;
           78:
           78:
           78:
           78;
           78;
           78;
           78:
           78;
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
           78
02D-007
02D-008
02G-011
02G-021
02G-025
02G-030
02G-041
02G-082
:02I-002
:02I-025
;02I-033
1021-034
:02I-040
:02I-042
:02J-008
:02J-015
:02K-055
:03C-003
:03F-002
:03F-008
:03F-020
:03F-026
:03F-030
:03F-031
:03F-033
:03F-035
:03F-039
:03F-040
:03F-041
:03F-042
:03F-043
:03F-044
:03F-047
:03F-049
:03F-052
:03F-056
:03F-059
 03F-061
 03F-062
 03F-064
 03F-065
 03F-066
 03F-067
 03F-068
 03F-073
 03F-078
 ;03F-080
 :03F-086
 ;03F-087
 :03F-088
 :03F-089
 ;03F-090
 S03F-095
 :03F-097
 :03F-098
 :03F-101
 :03F-102
 :03F-103
 :03F-104
 :03F-106
 :03F-107
 :03F-109
 :03F-110
 :03F-112
 :03F-114
 :03F-123
 :03F-125
 :03F-128
         78:03F-130
         78:04A-016
         78:040-008
         78:05A-009
         78:056-018
         78:05B-022
         78:05G-009
         78:050-011
         78:05G-012
         78:050-013
         78:050-014
         78:05G-015
         78:050-016
         78:050-033
         78:05G-038
         78:050-042
         78:05G-049
         78:06A-001
         78:06A-004
         78:06A-007
         78:06A-013
         78:06B-002
         78:063-005
         78:068-007
         78:060002
         78:060-002
         78:06E-001
         78:06G-003
         78:07A-001
         78:07A-002
         78:078-011
         78:078-017
         78:078-022
         78:088-004
         78:100002
         78:100005

Irrigation  Canals
          78:03F-042
          78:056-011
          78:078-027

Irrigation  Design
          78:03F-030
          78:03F-042
          78:03F-043
          78:03F-088
          78:03F-089
          78:03F-093
          78:03F-099
          78:03F-100
          78:03F-101
          78:03F-102
          78:03F-104
          78:03F-109
          78:03F-110
          78:06A-013
          78:06G-003
          78:088-006

Irrigation  Ditches
          78:03F-042
          78:03F-130
          78:040-008

Irrigation  Effects
          78:021-001
          78:021-006
          78:021-040
          78:03P-031
          78:03F-062
          78:03F-070
          78:03F-096
          78:03F-125
          78:05G-020
          78:060002

Irrigation Efficiency
          78:03F-030
          78:03F-034
          78:03F-039
          78:03F-042
          78:03F-046
          78:03F-047
          78:03F-048
          78:03F-053
          78:03F-054
          78:03F-058
          78:03F-063
          78:03F-064
          78:03F-072
          78:03F-077
          78:03F-079
          78:03F-080
          78:03F-081
          78:03F-083
          78:03F-085
          78:03F-096
          78:03F-098
          78:03F-099
          78:03F-100
          78:03F-104
          78:03F-105
          78:03F-106
          78:03F-125
          78:03F-127
          78:048-014
          78:068-005

 Irrigation  Operation
    and Maintenance
          78:03F-088
           78:06A-013
           78:080001

 Irrigation  Practices
           78:03F-034
           78:03F-035
           78:03F-051
           78:03F-052
           78:03F-063
           78:03F-067
           78:03F-079
           78:03F-096
           78:03F-106
           78:03F-125
           78:03F-127
           78:048-014
           78:05G-016
           78:05G-038
           78:05G-039
           78:06G-001

 Irrigation Programs
           78:03F-001
           78:03F-046
           78:03F-068
           78:03F-086
                                         322

-------
Irrigation Programs
   (cont.)
           78:03F-109
           78:03F-116
           78:06A-013
           78:068-009
           78:06G-001
           78:10C-005

Irrigation Return Flow
           78:05G-038

Irrigation Systems
           78:021-034
           78:03F-026
           78:03F-032
           78:03F-034
           78:03F-041
           78:03F-043
           78:03F-044
           78:03F-045
           78:03F-046
           78:03F-049
           78:03F-050
           78:03F-059
           78:03F-061
           78:03F-063
           78:03F-064
           78:03F-065
           78:03F-078
           78:03F-080
           78:03F-081
           78:03F-083
           78:03F-084
           78:03F-085
           78:03F-086
           78:03F-087
           78:03F-088
           78:03F-089
           78:03F-090
           78:03F-097
           78:03F-098
           78:03F-101
           78:03F-102
           78:03F-103
           78:03F-115
           78:03F-116
           78:03F-U7
           78:03F-118
           78:05G-045
           78:083-004
           78:086-005
           78:083-006

Irrigation Water
           78:026-023
           78:02G-045
           78:02G-046
           78:030-004
           78:030-001
           78:03F-012
           78:03F-032
           78:03F-033
           78:03F-045
           78:04A-003
           78:053-048
           78:05G-007
           78:05G-038
           78:060-002
Irrigation Wells
           78:03F-047

Isotherms
  *        78:02K-024
           78:02K-030
           78:02K-032
           78:02K-035
           78:02K-036
           78:02K-060
           78:02K-063
           78:02K-070
           78:058-028

Isotope Fractination
           78:02F-026

Isotope Studies
           78:02F-026
           78:02K-011
           78:02K-049
           78:02K-057
           78:073-006

Johnson Grass
           78:02K-016

Judicial Decisions
           78:06E-007

Kalman Filters
           78:02A-006
           78:083-011
Kansas
Kaolinite
Kentucky
           78:03F-051
           78:05G-063
           78:02K-025
           78:02K-035
           78:02K-037
           78:02K-063
           78:03F-027
Kinematic Models
           78:083-001

Kinetics
           78:02G-056
           78:021-013
           78:02K-040
           78:02K-065

Labor Savings
           78:03F-096

Laboratory Equipment
           78:02J-001
           78:073-034
           78:073-035

Laboratory Tests
           78:02F-001
           78:02F-027
           78:020-007
           78:02G-010
           78:02G-012
          78:02G-014
          78:02G-016
          78:02G-022
          78:02G-024
          78:02G-034
          78:02G-040
          78:02G-058
          78:02G-062
          78:020-066
          78:026-081
          78:02J-001
          78:02J-002
          78:02K-044
          78:02K-064
          78:02K-067
          78:02K-074
          78:02K-075
          78:040-004
          78:058-003
          78:053-042
          78:053-050
          78:053-064
          78:05G-038
          78:073-016
          78:073-024
          78:073-034
          78:073-035
          78:08G-001
Lake Erie
          78:05G-067

Lake Hefner
          78:020-002

Lake Ontario
          78:020-002

Lake-Water Budget
          78:02F-015
Lakes
          78:02F-015
          78:053-041
Land Management
          78:02J-012
          78:02J-024
          78:04A-012
          78:050-024
          78:05G-063
          78:05G-067
          78-.06E-021

Land Reclamation
          78:02G-023
          78:040-007

Land Resources
          78:06E-021

Land Subsidence
          78:06A-009
Land Use
          78:02J-012
          78:04A-012
          78:040-005
          78:05A-001
          78:05A-010
                                     323

-------
Land Use
   (cont.)
           78:05A-021
           78:058-014
           78:05G-003
           78:05G-046
           78:06A-014
           78:06E-021
Landscaping
           78:030-001
Latent Heat
           78:02G-020

Lateral Conveyance
   Structures
           78:088-004
           78:08B-006
Lea Valley
 Leachate
 Leaching
            78:046-010
            78:02G-005
            78;02G-006
            78:020-010
            78:020-039
            78:021-033
            78:02K-015
            78:02K-064
            78:02K-067
            78:02K-071
            78:04A-016
            78:05A-002
            78:05B-003
            78:05B-012
            78:058-025
            78:050-042
            78:050-076
            78:050-077
            78:020-012
            78:020-019
            78:020-023
            78:020-039
            78:020-043
            78:020-045
            78:020-065
            78:020-077
            78:020-078
            78:021-007
            78:02K-018
            78:02K-019
            78:02K-041
            78:02K-055
            78:02K-071
            78:03C-003
            78:03C-004
            78:03F-001
            78:03F-005
            78:03F-008
            78:03F-010
            78-.03F-015
            78:03F-016
            78:03F-044
            78:03F-056
Lead
                              Leakage
          78:03F-060
          78:03F-096
          78:03F-109
          78:04A-016
          78:05A-003
          78:058-011
          78:058-026
          78:058-035
          78:058-043
          78:058-046
          78:05G-002
          78:050-021
          78:050-036
          78:050-042
          78:050-044
          78:02K-002
          78:02F-003
          78:02F-018
          78:050-002
Leaky Aquifers
          78:02F-003

Least Squares Method
          78:048-013
          78:05A-006
Leaves
          78:021-038
          78:040-004
          78:078-007
 Legal Aspects
           78:03F-107
           78:048-004
           78:040-001
           78:06E-005
           78:06E-007

 Legislation
           78:050-047
           78:050-048
           78:06E-006
           78:06E-009
 Legumes
 Lemons
 Lettuce
 Lime
           78:021-011
           78:078-006
           78:03F-026
           78:03F-063
           78:058-013
 Limiting Factors
           78:03F-072

 Linear Programming
           78:03F-009
           78:03F-101
           78:04A-
           78:04A-
           78:04A-
           78:050-
           78:05G-
           78:050-
           78:06A-
           78:06A-
           78:068'
           78:068
           78:06E
•001
•003
•004
•003
•058
•075
-008
-016
•Oil
-012
-015
                                                          Linings
           78:04A-018
           78:080-001
Liquid Wastes
           78:03F-059
                                                          Litter
                                                          Livestock
                                                                     78:04D-004
                                       78:05A-016
                                       78:05A-019
Load Distribution
           78:03F-069

Loam
           78:020-061
           78:020-079
           78:02J-002
           78:058-005

Local Government
           78:06E-014
 Loess
            78:040-006
 Lognormal Distributions
            78:02E-002

 London Basin (London)
            78:048-010

 Long Channels
            78:02J-014

 Longitudinal Dispersion
            78:020-062
                             Louisiana
                             Low Flow
            78:03F-089
            78:046-005
                                        78:03F-097
 Low-Flow Augmentation
            78-.03F-090
 Lysimeters
             78:02D-008
             78:020-005
             78:020-046
             78:021-007
             78:02K-044
                                        324

-------
Lysimeters
    (cont.)
Maryland
          78:05G-062
            78:02K-057
            78:05A-003
            78:05B-025
Magnesium
           78:021-043
           78:02K-003
           78:02K-024
           78:02K-035
           78:02K-047

Magnesium Carbonate
           78:02K-065

Maintenance
           78:03F-050
           78:05G-026
           78:08A-001

Maintenance Costs
           78:08A-002
Malathion
           78:058-040
Malt Barley
           78:03F-096
Management
           78:03F-036
           78:03F-062
           78:056-064
           78:05G-031
           78:05G-047
           78:05G-049
           78:050-050
           78:05G-059
           78:05G-062
           78:050-064
           78:05G-069
           78:05G-070
           78:06A-010
           78s06A-013
           78:06B-001
           78:068-002
           78:068-014
           78:06E-010
           78:06E-011
           78:06E-013
Manganese
           78:026-037
           78:02K-027
           78:02K-052
           78:02K-072

Mannings Equation
           78:088-011
             r
Mannings Formula
           78:088-011
Marking
           78:078-002
Markov Processes
           78:02G-054
           78:088-013
Mass Transfer
          78:02E-003
          78:02G-013
          78:058-061
Materials
          78:05G-026
Mathematical Models
          78:02A-002
          78:02A-007
          78:02A-008
          78:02A-009
          78:020-001
          78:020-005
          78:02E-001
          78:02E-004
          78:02E-005
          78:02E-008
          78:02E-009
          78:02F-003
          78:02F-006
          78:02F-007
          78:02F-008
          78:02F-009
          78:02F-010
          78:02F-012
          78:02F-013
          78:02F-014
          78:02F-016
          78:02F-018
          78:02F-022
          78:02F-028
          78.-02G-001
          78:02G-002
          78:02G-003
          78:02G-004
          78:02G-006
          78:020-007
          78:02G-008
          78:02G-009
          78:020-013
          78:020-018
          78:02G-027
          78:020-041
          78:02G-042
          78:02G-048
          78:020-049
          78:020-052
          78:020-055
          78:020-056
          78:020-061
          78:020-062
          78:020-063
          78:020-068
          78:020-072
          78:020-080
          78:020-086
          78:02J-013
          78:02J-014
          78:02J-017
          78:02K-065
          78:03F-009
          78:03F-054
          78:03F-099
          78:03F-124
          78:04A-002
          78:04A-005
          78:04A-007
          78:04A-015
          78:040-005
          78:05A-006
          78:05A-007
          78:05A-020
          78:058-009
          78:058-010
          78:058-014
          78:05B-015
          78:058-016
          78:058-017
          78:058-039
          78:058-042
          78:058-057
          78:058-058
          78:058-059
          78:058-060
          78:050-003
          78:05G-030
          78:050-031
          78:050-066
          78:06A-001
          78:06A-002
          78:06A-003
          78:06A-010
          78:068-017
          78:06E-011
          78:078-027
          78:088-013

Mathematical Studies
          78:02E-009
          78:02F-004
          78:02F-013
          78:02F-024
          78:02F-025
          78:020-064
          78:03F-013
          78:088-001
          78:088-007

Mathematics
          78:020-001
          78:02E-008
          78:02J-014

Matric Potential Sensors
          78:020-071

Meanders
          78:050-030

Measurement
          78:020-014
          78:02G-075
          78:02J-001
          78:02K-061
          78:03F-085
          78:050-003
          78:078-015
          78:078-021
          78:078-023
          78:078-027
          78:078-030
          78:088-009
                                    325

-------
Mechanical Properties
           78-.02J-002
Melt Water
Mercury
           78:02K-044
           78:021-033
           78:02K-Q33
           78-.02K-055
           78:05A-022
Metabolism
Metals
           78:021-014
           78:021-029
           78:078-016
           78:02K-064
Meteorological Data
           78;02D-003
Meteorology
           78:020-002
           78:07B-015

Methodology
           78:02E-007
           78:02F-011
           78:026-021
           78:03D-001
           78-.03F-095
           78:05B-065
           78:068-019
           78:068-021
           78:078-022
           78:076-023

Mexican Water Treaty
           78-.05G-022
           78:06E-006

Michigan
           78:021-043
           78-.03F-073
           78:05A-001
           78:050-059

Micro Environment
           78:021-020

Micro Organisms
           78:02K-042
           78:05B-019
           78:058-050

Microdegradation
           78:02K-033
           78:02K-042
           78.-05B-027
           78:056-029
           78:05B-056
           78:076-016
 Microwaves
 Migration
            78:076-034
            78-.05B-034
Mine Wastes
          78.-02J-009
          78:02K-031

Mineralization
          78:058-018
Minerology
Mining
          78:021-043
          78:02J-003
          78-.02K-050
          78:02J-009
          78:02J-010
                              Minnesota
                                        78-.05A-004
                              Mississippi
                                        78:05G-043
                              Missouri
          78:02J-007
          78:04D-006
          78:056-008
Missouri River
          78:056-015
Mixing
          78:05B-011
          78-.05B-013
          78:05B-015
Model Calibration
           78:020-063

Model Studies
           78-.02A-002
           78-.02A-003
           78:02A-004
           78.-02A-005
           78:02A-010
           78:02A-011
           78:02C-001
           78:020-001
           78:02D-007
           78:020-008
           78:02E-001
           78.-02E-002
           78:02E-003
           78:02E-004
           78:02E-007
           78-.02E-008
           78:02E-009
           78-.02E-010
           78:02P-001
           78:02P-003
           78-.02F-008
           78:02F-010
           78:02F-011
           78:02F-012
           78:02F-013
           78:02F-014
           78:02F-015
           78:02F-016
           78:02F-022
           78s02G-001
           78-.02G-002
           78:02G-003
        326
         78:02G-
         78:02G-
         78:02G-
         78:02G-
         78:02G-
         78:02G-
         78:02G
         78:02G
         78:02G
         78:02G-
         78-.02G-
         78:02G-
         78:02G-
         78:02G-
         78:02G-
         78:021-
         78:02J-
         78-.02J-
         78-.02J-
         78:02J-
         78:02J-
         78.-02J-
         78:036-
         78:03F-
         78:03F-
         78-.03F-
         78:03F-
         78:04A-
         78:04B-
         78:048-
         78:048-
         78:04B-
         78:040-
         78:05B-
         78:058-
         78:058-
         78:05B-
         78:053-
         78:05B-
         78-.05B-
         78:05B-
         78:058-
         78:058-
         78:056-
         78:056-
         78:050
         78:05G'
         78:05G-
         78:05G-
         78:05G-
         78.-06A'
         78:06A'
         78:06A
         78:06A
          78.-06A
          78:066'
          78:068
          78:066
          78:066
          78:066
          78:066
          76:06B
          78:06E
          78:08B
          78;08B
          78:08B
          78:088
006
007
008
009
013
016
027
041
052
054
055
060
063
080
081
004
010
013
014
015
019
024
001
•054
056
123
•124
•005
•002
•007
•Oil
•012
•005
•010
•013
•014
•015
-016
-017
-018
•039
-042
•057
•058
•061
-007
-065
-067
-072
-075
-002
-008
-009
-010
-015
•016
-009
-012
-015
-017
-019
-020
 021
-015
-001
-004
-Oil
-013
Mohave Valley (Arizona)
          78:040-007

-------
Moisture
          78:07B-034
Moisture Availability
          78:03F-055
          78:07B-017
          78:07B-036

Moisture Content
          78:02G-001
          78:02G-002
          78:02G-006
          78:020-016
          78:020-027
          78:020-028
          78:020-030
          78:020-040
          78:020-048
          78:020-061
          78:020-066
          78:020-067
          78:020-075
          78:020-076
          78:020-080
          78:020-084
          78:020-085
          78:021-020
          78:021-028
          78:02K-038
          78:03F-033
          78:03F-039
          78:03F-055
          78:05A-022
          78:078-017
          78:07B-022
          78:078-034

Moisture Deficit
          78:02A-008
          78:020-038
          78:020-076
          78:021-018
          78:021-019
          78:021-025
          78:021-028
          78:021-029
          78:021-034
          78:021-036
          78:021-038
          78:021-040
          78:021-041
          78:021-042
          78:030005
          78:03F-021
          78:03F-022
          78:03F-048
          78:03F-051
          78:03F-100

Moisture Meters
          78:020-016
          78:03F-033

Moisture Stress
          78:021-006
          78:021-018
          78:021-019
          78:021-025
          78:021-028
          78:021-034
          78:021-036
          78:021-038
          78:021-041
          78:021-042
          78:030002
          78:03F-021
          78:03F-022
          78:03F-031
          78:03F-062

Moisture Tension
          78:020-029
          78:020-073
          78:020-076
          78:020-084
          78:021-008
          78:021-011
          78:021-019
          78:021-020
          78:021-038
          78:03F-039
          78:03F-118
          78:078-017

Moisture Uptake
          78:021-008
          78:021-013
          78:021-023

Molybdenum
          78:02K-051

Momentum Equation
          78:020-053
          78:04A-007
Mulching
Monitoring
Monocots
Montana
          78:03F-014
          78:05A-007
          78:05A-008
          78:078-005
          78:02K-033
          78:078-007
Monte Carlo Method
          78:02E-001
          78:02E-009
          78:02F-007

Montmorillonite
          78.-02K-012
          78:02K-025

Moody Resistance Diagram
          78:088-005
          78:088-010
Mosquitoes
Movement
          78:060-001
          78:02K-016
          78:02K-017
          78:03F-055
          78:040-004
Multiple Purpose
  Reservoirs
          78:04A-004

Multi-Regression
  Equations
          78:020-002

Municipal Wastes
          78:050007

Natural Gas
          78:03F-038
          78:03F-067
Nebraska
          78:03F-046
          78:03F-051
          78:03F-060
          78:03F-083
          78:03F-086
          78:03F-106
          78:04A-009
          78:04A-016
          78:05A-010
          78:05G-076
Net Profit
          78:068-009

Network Design
          78:02F-023
          78:05A-007
Networks
          78:05A-007
          78:068-003
Neutron Activation
  Analysis
          78:078-009
Nevada
New York
                                        78:058-002
          78:058-016
New Hampshire
          78:020001
New Mexico
New York
Moving Boundaries
          78:02F-004
                              Nickel
                              Nitrogen
          78:03F-038
          78:02K-034
          78:056-060
          78:050-068
          78:068-017
          78:021-032
          78:02K-061
                                      327

-------
 Nitrates
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
             78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
            78
 :02G-035
 :02G-036
 :02G-050
 :02I-014
 -•021-028
 .-02K-004
 :02K-005
 :02K-009
 :02K-018
 .•02K-020
 :02K-048
 :02K-057
 :02K-067
 :02K-068
 :02K-071
 :03F-001
 :03F-005
 :03F-012
 :03F-015
 .-03F-016
 :03F-056
 :03F-057
 :03F-060
 :04A-016
 :05A-004
 :05A-005
 :05A-009
 :05A-021
 :05B-001
 :05B-011
 :05B-020
 :05B-021
 :05B-025
 :05B-039
 :05B-043
 :05B-047
 :05B-054
 :05B-064
 :05D-001
 .-05G-002
 :OSG-018
 :05G-021
 :05G-034
 J05G-037
 •-05G-045
 :05G-073
 :05G-074
 :05G-076
:056-077
:07B-008
: 078-023
:10A-001
                  Nitrites
          78.-02K-049
          78:05A-005
          78:05A-009
          78:05B-054
          78:07B-008
Nitrogen
Nitrification
           78:02K-017
           78:02K-018
           78t02K-022
           78i03F-004
           78:03F-005
           78:03F-029
           78:05A-005
           78:05A-021
           78:053-018
           78:058-047
           78:058-054
           78:050-002
           78:056-045
           78:07B-002
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78:
          78;
          78;
          78;
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78
          78
          78
          78
          78
          78
          78
         78
         78
         78
         78
         78
         78
         78
         78
         78
         78:
         78;
         78;
         78:
         78i
         78:
         78:
         78;
         78:
         78:
         78:
         78:
         78:
         78:
         78:
        323
 :02A-001
 :02A-004
 .-02F-002
 :02G-032
 :02G-035
 :02G-036
 :02G-051
 :02I-007
 : 021-016
 :02I-026
 :02I-028
 :02I-029
 :02I-030
 :02K-001
 :02K-004
 :02K-009
 :02K-019
 :02K-022
 r02K-029
 :02K-038
 :02K-040
 :02K-043
 :02K-048
 :02K-057
 02K-066
 02K-067
 02K-068
 02K-071
 02K-074
 02K-075
 03F-001
:03F-002
.-03F-003
:03F-004
:03F-005
:03F-010
:03F-012
.•03F-013
:03F-014
:03F-015
:03F-01€
:03F-017
:03F-018
:03F-019
:03F-022
:03F-023
:03F-028
:03F-029
J03F-056
:03F-057
:03F-060
:03F-073
:04A-016
:05A-020
:05A-021
058-006
058-008
058-011
058-018
058-020
058-040
058-041
058-044
            78:058-046
            78:058-047
            78:05B-064
            78-.05B-067
            78:05C-003
            78:05G-005
            78:05G-007
            78:05G-008
            78:05G-021
            78:05G-034
            78:05G-037
            78.-05G-043
            78:05G-045
            78:050-074
            78:050-076
            78:05G-077
            78:06A-008
            78:06B-020
            78:076-010
            78:078-013
            78:078-024
            78:10A-001

 Nitrogen Compounds
            78:03F-057
            78:05A-009
            78:05G-008
            78:05G-037
           78:07B-002

 Nitrogen Cycle
           78:02K-057
           78:02K-061
           78:058-025
           78:058-064
           78.-05G-008
           78:068-020
           78:10A-001

 Nitrogen Fixation
           78:02G-026
           78:021-009
           78:03F-060
           78:050-003
           78:056-007
           78.-05G-008
           78:078-006

 Nitrogen Removal
           78:058-043

 Noise Covariances
           78:02A-006

 Nonlinear  Programming
           78:04A-004
           78:05G-031

 Nonpoint Pollution Sources
           78:058-067

 Nonuniform  Flow
          78:026-009

North Carolina
          78:02K-069
          78:03F-074
          78:03F-075
          78:056-034
          78:06E-009

-------
North Dakota
           78:02G-079
Nutrients
Nozzles
           78:03F-058
           78:03F-072
           78:03P-103
Nuclear Energy
           78:03F-067
           78:063-004

Numerical Analysis
           78:02F-004
           78:02F-006
           78:02F-015
           78:02F-017
           78:02F-020
           78:02F-024
           78:02G-015
           78:02G-027
           78:02G-048
           78:020-049
           78:02G-050
           78:02G-060
           78:02H-002
           78:02J-017
           78:04A-002
           78:048-002
           78:06A-004
           78:06A-005
           78:06A-009

Nutrient Removal
           78:02A-004
           78:021-017
           78:021-043
           78:02K-004
           78:02K-019
           78:02K-027
           78:02K-060
           78:02K-072
           78:03F-010
           78:03F-018
           78:03F-027
           78:03F-060
           78:04A-013
           78:05A-004
           78:05A-016
           78:05A-018
           78:05A-020
           78:05B-008
           78:058-037
           78:058-046
           78:058-049
           78:058-064
           78:058-068
           78:05G-029
           78:056-070
           78:05G-072
           78:068-017

Nutrient Requirements
           78:021-027
           78:021-030
           78:03F-006
           78:03F-023
           78:03F-061
           78:05G-070
           78:078-004
           78:078-013
Oats
Ohio
Oil
          78:02G-032
          78:02G-033
          78:020-051
          78:021-007
          78:021-019
          78:021-043
          78:02K-045
          78:02K-072
          78:03F-008
          78:03F-019
          78:03F-061
          78:05A-012
          78:05A-017
          78:058-041
          78:058-049
          78:058-067
          78:05G-029
          78:05G-030
          78:050-037
          78:05G-043
          78:078-010
          78:078-012
          78:078-013
          78:078-019
          78:021-043
          78:02K-016
          78:03F-027
          78:02K-011
          78:058-007
          78:058-025
          78:03F-067
          78:068-004
Oil Shales
Oklahoma
          78:068-004
          78:050-037
Ombone River Basin
          78:02A-006

On-Site Data Collections
          78:058-041

On-Site Investigations
          78:02K-044
          78:048-010
          78:04D-002
          78:058-002
          78:058-041
          78:05G-038
Onions
          78:021-021
Open Channel Flow
          78:02J-016
          78:078-011
          78:088-002
          78:088-011
                                  329
Open Channel Hydraulics
           78:088-011

Open Channels
           78:02J-013
           78:058-061
           78:088-001
           78:088-002
           78:088-008
           78:088-011

 Operating  Rules
           78:04A-004

 Operation  and Maintenance
           78:03F-038

 Operations Research
           78:06A-010

 Optimization
           78:02A-002
           78:02F-011
           78:03F-009
           78:03F-092
           78:03F-101
           78:04A-001
           78:04A-003
           78:04A-004
           78:058-009
           78:050-003
           78:05G-010
           78:050-031
           78:06A-008

 Optimum Development Plans
           78:050-004
                             Oranges
                             Oregon
          78:03F-065
          78:050-044
          78:06A-007
Organic Acids
          78:021-014

Organic Compounds
          78:02K-014
          78:02K-021

Organic Material
          78:02K-006
          78:02K-027
          78:050-001

Organic Matter
          78:02F-002
          78:020-037
          78:021-005
          78:021-033
          78:02K-026
          78:02K-050
          78:02K-051
          78:02K-058
          78:02K-074
          78:02K-075
          78:03F-023

-------
Organic Matter
   (cont.)
            78:03F-060
            78:03F-113
            78:078-018

Organic Soils
            78:020-030
            78:02K-067
            78:02K-070
            78:058-046
            78:05G-002

Organic Wastes
            78:050-042

Organophosphorus Compounds
            78:02K-049
            78:02K-053
Ozone
Pans
Paraquat
78:07B-023


78:021-003


78:05B-028
                             Peppers
                                       78:058-040
Orificies
Orthogonal
           78:03F-032
           78:088-009
           78:020-061
Osmotic Pressure
           78:021-031
           78:021-038
           78:030-004
           78:03F-005
           78:078-017

Overburden
           78:020-047

Overirrigation
           78:03F-096

Overland Flow
           78:02E-010
           78:02J-005
           78:02J-018
           78:05B-012
           78:058-036
           78:058-038

Oxidation-Reduction
  Potential
           78:02K-068
           78:058-047
           78:058-056
           78:05G-074
           78:078-020
Oxidation
Oxygen
           78:02K-031
           78:02K-052
           78:02K-074
           78:02K-075
           78:058-002
           78:021-002
           78:02K-052
           78:078-030
           78:078-035
Particle Size
          78:02G-079
          78:02J-027
          78:02K-003
          78:02K-019
          78:02K-041
          78:040-002
          78:058-028

Partitioning Procedure
          78:050-031

Pasture Management
          78:050-051
Pastures
          78:04A-012
Path of Pollutants
          78:05A-001
          78:058-003
          78:058-013
          78:058-014
          78:058-016
          78:058-057
          78:058-058
          78:058-062

Pathogenic Bacteria
          78:058-050

Pattern Recognition
          78:02E-007
Peaches
          78:03F-061
          78:03F-075
Peak Discharge
          78:04A-015
Peak Loads
Peanuts
Peat
          78:03F-069
          78:02K-041
          78:02G-026
          78:02K-006
Penetration
          78:02G-021

Pennsylvania
          78:05A-003
          78:068-011
          78:060-002
Perched Water
          78:058-052
          78:05G-025
          78:078-036

Percolating Water
          78:02G-019
          78:058-040

Percolation
          78:020-005
          78:02G-009
          78:056-040

Performance
          78:03F-091
          78:03F-097
          78:03F-098

Permeability
          78:02F-017
          78:02G-023
          78:04A-018
          78:048-003

Persistence
          78:02K-016
          78:058-026
          78:058-027
          78:058-033
          78:058-035
          78:058-050
          78:058-056

Pesticides
          78:02K-062
          78:03F-036
          78:03F-067
          78:040-003
          78:05A-003
          78:058-024
          78:058-027
          78:05B-028
          78:058-029
          78:058-030
          78:058-031
          78:058-032
          78:058-033
          78:058-034
          78:058-035
          78:058-036
          78:058-040
          78:058-056
          78:050-002
          78:05G-073
          78:06A-002
          78:06A-003
          78:06G-002
          78:078-016
          78:OiOC-003

Pesticide Kinetics
          78:026-056
          78:058-030
          78:058-032
          78:078-016
                                       330

-------
Pesticide Residues
           78:05B-023
           78:05B-027
           78:058-033
           78:058-034
           78:058-035
           78:058-036
           78:058-056
           78:050-072
           78:078-016

Phosphate Transport
           78:05A-011
Phosphates
           78:021-022
           78:02K-004
           78:02K-012
           78:02K-032
           78:02K-037
           78:02K-063
           78:03F-025
           78:05A-011
           78:058-007
           78:058-008
           78:05G-030
           78:078-008
Phosphorus
           78:02G-032
           78:021-005
           78:021-009
           78:021-012
           78:02K-014
           78:02K-021
           78:02K-036
           78:02K-039
           78:02K-045
           78.-02K-051
           78:02K-060
           78:02K-069
           78:02K-072
           78:03F-003
           78:03F-025
           78:05A-016
           78:05A-017
           78:05A-019
           78:05A-020
           78:058-003
           78:058-040
           78:05B-041
           78:058-044
           78:05B-046
           78:05C-007
           78:05G-030
           78:05G-037
           78:05G-043
           78:06A-008
           78:078-010
           78:07B-014
           78:078-019

Phosphorus Compounds
           78:02G-033
           78:02K-014
           78:05A-011
           78:05B-007
           78:058-008
Photosynthesis
          78:021-018
          78:05C-003
          78:050005

Physical Properties
          78:02J-003

Piezometers
          78:078-025
Pipe Flow
Pipelines
          78:088-005
          78:088-010
          78:03F-053
          78:03F-088
          78:08A-001
          78:088-005
          78:088-006
Pipes
          78:08A-001
          78:088-003
          78:088-008
          78:08G-002
          78:08G-003

Pit Recharge
          78:02F-001
          78:048-003
Plankton
Planning
          78:05G-030
          78:058-009
          78:05G-004
          78:050-050
          78:05G-060
          78:050-061
          78:05G-062
          78:06A-010
          78:06A-014
          78:06E-004
          78:06E-009
          78:06E-013
          78:06E-014
          78:06G-002

Plant Breeding
          78:03C-001

Plant Growth
          78:021-001
          78:021-019
          78:021-027
          78:021-035
          78:021-043
          78:02K-004
          78:02K-072
          78:03C-002
          78:03F-021
          78:03F-025
          78:078-007

Plant Nutrition
          78:02K-033
Plant  Physiology
           78:021-019
           78:03C-001

Plant  Population
           78:021-040

Planting Management
           78:03F-002
           78:03F-124

Plastic Pipes
           78:088-010
           78:08G-002
           78:080-003

Platte River (Nebraska)
           78:05A-010
Playas
          78:06E-003
Pleistocene Epoch
          78:02K-006
Plutonium
Podzols
          78:040-001
          78:040-002
          78:02K-015
Political Aspects
          78:06G-002
                             Pollen
          78:058-041
Pollutant Identification
          78:05A-019
          78:05A-022
          78:058-020
          78:05G-005
          78:05G-051
Pollutants
          78:02A-004
          78:02K-002
          78:02K-022
          78:02K-032
          78:02K-049
          78:03F-019
          78:04A-013
          78:05A-001
          78:05A-002
          78:05A-005
          78:05A-007
          78:05A-022
          78:058-006
          78:058-010
          78:058-028
          78:058-030
          78:058-031
          78:058-032
          78:058-034
          78:058-037
          78:058-039
          78:058-055
          78:058-057
          78:058-058
                                   331

-------
Pollutants
  (cont.)
           78:058-067
           78:050002
           78:050-001
           78:05G-021
           78:05G-037
           78:050-063
           78:06A-003
           78:06A-016
           78:06B-021

Pollution Abatement
           78:02A-014
           78:02J-006
           78:03C-003
           78:03F-011
           78:04A-009
           78:05B-006
           78:058-032
           78:056-005
           78:05G-021
           78:05G-024
           78:056-051
           78:05G-061
           78:056-069
           78:06A-003
           78:06A-016
           78:06E-005
Ponding
Ponds
           78:026-052
           78:026-055
           78:026-072
           78:056-038
Pore Pressure
           78:026-018
           78:026-034
           78:026-057
           78:026-080
           78:048-003
Pore Water
           78:02F-027
           78:026-034
           78:048-003
Porosity
           78:026-024
           78:026-042
           78:026-057
           78:026-081
           78:048-009

Porous Media
           78:02F-001
           78:02F-004
           78:02F-006
           78:02F-009
           78:02F-013
           78:02F-020
           78:02F-023
           78:02F~025
           78:026-018
           78:026-042
           78:026-061
           78:026-063
          78:026-064
          78:026-068
          78:048-002
          78:06A-009
          78:088-012

Potassium
          78:026-032
          78:021-007
          78:021-014
          78:021-017
          78:021-021
          78:021-023
          78:02K-004
          78:02K-026
          78:02K-035
          78:02K-060
          78:02K-070
          78:03F-003
          78:078-004
          78:078-010

Potassium Nitrate
          78:058-040

Potatoes
          78:03F-005
          78:03F-036
          78:03F-063
          78:03F-070
          78:058-043

Potentiometric Level
          78:048-013

Powerplants
          78:048-001
          78:058-015

Precipitation
          78:02A-007

Precipitation (Atmospheric)
          78:02A-005
          78:02A-008
          78:028-001
          78:026-052
          78:02J-004
          78:03F-123
          78:05A-012
          78:058-006
          78:058-023
          78:058-041
          78:078-015
          78:078-028

Precipitation Excess
          78:02A-005
          78:026-052

Prediction
          78:06A-001
          78:060-001

Preservation
          78:078-008
Pressure Conduits
          78:088-006

Pressure Head
          78:026-003
          78:026-048
          78:026-064
          78:03F-072
          78:03F-076
          78:03F-087
          78:03F-110
          78:03F-127
          78:078-025
Pricing
          78:056-016
          78:10C-005
Probability
          78:028-001
          78:02E-001
          78:02E-002
          78:026-074
          78:05A-006

Production Function
          78:03F-009

Productivity
          78:021-009
          78:03F-003
          78:03F-070
          78:03F-089
                                                           Profiles
                                                           Profit
Programs
          78:026-047
          78:03F-009
          78:03F-096
          78:03F-107
          78:056-063
          78:06E-013
          78:06E-020

Project Evaluation
          78:100005

Project Planning
          78:06A-013
Projection
          78:04A-008
Projects
          78:04A-003
Pressure
          78:026-024
          78:026-080
Properties
          78:05A-015

Public Health
          78:058-004

Pump Testing
          78:03F-038
          78:03F-082
                                    332

-------
Pumping
          78:02F-003
          7B-.02F-012
          78:02F-018
          78:02F-027
          78:048-014
          78:08C-001

Pumping Plants
          78:03F-038
          78:03F-066
          78-.03F-082
Pumps
Pyrite
Quartz
          78-.03F-038
          78:03F-066
          78:03F-082
          78:02K-031
          78:02K-007
Radiation
          78:020-006
          78:02F-021
          78:03F-007
          78:03F-026

Radioactive Wastes
          78:05B-042

Radioactivity
          78:05B-042
          78:050-001

Radiochemical Analysis
          78:078-009

Radioisotopes
          78:02G-040
          78:021-009
          78:02K-062
          78:04D-002
Rain
          78:058-041
Rain Gages
Raindrops
          78:078-015
          78:07B-028
          78:02J-018
Rainfall
          78:028-001
          78:Q2E-011
          7i8:02G-052
          78:02G-055
          78:02G-058
          78:020-072
          78:02K-023
          78:04A-017
          78:04D~005
          78:05A-012
          78:058-006
          78:058-023
          78:058-027
          78:05G-037
          78:06A-006
          78:078-015
          78-.07B-028

Rainfall Intensity
          78:02A-009
          78:02G-052
          78:02J-018
          78-.02J-025
          78:04A-017

Rainfall-Runoff
   Relationships
          78:02A-006
          78:02A-009
          78:058-023

Range Grasses
          78:078-006

Range Management
          78:05G-051
          78:07B-006
Ranges
          78:04A-006
          78:058-012
Rates of Application
          78-.02G-032
          78:02G-033
          78:02K-018
          78-.03F-023
Recession Curves
          78:03F-054
          78:03F-099
          78:03F-100

Recharge Wells
          78:048-010

Reclamation
          78-.02G-065
          78:03F-006
          78:05G-036

Reduction (Chemical)
          78:021-014
          78:02K-029
          78:02K-048
          78:02K-052
          78:02K-068

Regional Analysis
          78t05G-035

Regression Analysis
          78-.02A-001
          78:02E-001
          78:021-005
          78:02J-009
          78:02J-022
          78:02K-050
          78:03F-062
          78:03F-105
          78:03F-126
          78:05B-001
          78:058-036

        333
          78:05G-036
          78.-05G-046
          78:078-004

Remote Sensing
          78-.02F-021
          78:02G-031
          78:03F-112
          78:060-001
          78:078-025

Rental Market
          78:05G-033

Repairing
          78:08A-001

Rescaled Adjusted Range
          78.-02E-004
          78:02E-008
          78:02E-009

Research and Development
          78-.02J-011
          78:10C-002

Reservoir Design
          78s04A-004

Reservoir Leakage
          78:08G-00]

Reservoir Operation
          78:02H-001
          78:04A-001
          78-.04A-003
          78:04A-004

Reservoir Releases
          78.-02H-001

Reservoir Storage
          78:04A-008

Reservoirs
          78:020-004
          78:02H-001
          78:02H-002
          78:04A-008
          78:04A-018
          78:088-013

Resistence Coefficient
          78:088-011

Resource Allocation
          78-.03F-009
          78s05G-035

Respiration
          78s05C-006

Response Function
          78J03F-095
Retardance
          78:02E-010
Retention
          78:02G-079
          78:02G-084

-------
Return Flow
          78:
          78:
          78:
          78
          78
          78
          78
          78
          78
          78
          78
          78
          76
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
                              River Beds
 02J-015
 03F-014
 03F-085
:05A-002
:05A-018
:05B-002
:05B-006
:05B-037
:05B-056
-.05G-020
:05G-022
:05G-033
:05G-039
:05G-044
:05G-045
:05G-073
.-OSG-074
.-05G-075
:05G-077
:06B-001
:07A-002
.•lOC-001
:10C-002
:10C-006
                            78-.08B-001
River Flow
 Re turn  (Monetary)
           78:06C-001

 Revegetation
           78:050-001
 Reviews
           78:03F-112
           78.-04A-006
           78:068-021
           78:100-003

 Reynolds  Number
           78:08B-010

 Rice
           78:02G-C32
           78:02G-051
           78:021-037
           78:02K-001
           78:02K-040
           78:02K-065
           78.-03F-006
           78:03F-062
           78:056-056
           78:05G-039
           78t06A-006

 Rill Erosion
           78:02J-021
 Risks
           78:03F-087
 River Basin
           78-.05A-008
           78-.05G-035

 River Basin Management
           78:05G-016
          78.-02E-003
          78:02E-008
          78:05A-008
          78:088-013
Rivers
          78:058-010
          78:05B-013
          78-.05B-015
          78:05B-042
          78:08B-013

River Systems
          78-.05G-031
          78:05G-033

Root Development
          78:021-023
          78:02K-004
          78:03C-002
          78:078-005

Root Distribution
          78:021-008

Root Systems
          78:021-004
          78:021-012
          78:021-013
          78:021-021
          78:021-023
          78:038-001

Root  Zone
          78i02G-021
          78:02G-076
          78.-03F-013
          78:058-040
          78:073-019

Roughness Coefficient
          78:02J-022

 Roughness (Hydraulic)
          78:02E-010
          78:02J-016
                   Routing
                   Runoff
                             78:06A-008
                             78:02E-011
                             78.-02G-005
                             78:020-021
                             78:02G-052
                             78:02G-058
                             78:02-1-037
                             73:02J-010
                             78:02J-012
                             7B:02J-018
                             78:02J-027
                             78-.02K-032
         78:03F-054
         78:03F-070
         78-.03F-072
         78-.03F-081
         78:03F-099
         78:03F-123
         78:04A-006
         78:04A-009
         78.-04A-010
         78:04A-012
         78.-04A-013
         78.-04A-017
         78:05A-002
         78:05A-017
         78:05A-018
         78:05B-003
         78 :05B-006
         78:058-014
         78:053-025
         78:050-029
         78:056-031
         78:05B-032
         78:05B-036
         78:056-037
         78:056-046
         78.-05G-029
         78:05G-038
         78:05G-043
         78:05G-059
         78:06A-008
          78:06E-003
          78:07B-032
          78:10C-003

Saint Venant Equation
          78:Q8B-001

Salaquifers
          78-.04B-013

Saline Soils
          78.-02G-014
          78:02G-071
          78:03C-002
          78:03C-004
          78:030-005
          78:053-038
          78:05G-009
          78s05G-011
          78-.05G-028
          •78;07A-003

Saline Water
          78:02G-045
          78-.02G-046
          78:021-002
          78:021-025
          78:030-002
          78:030-003
          78:030-004
          78:030-006
          78:050-001
          78:056-016
          78:05G-023
          78:056-028
          78:07A-003
                                         334

-------
Saline Water Intrusion
          ;78j02F-008

Saline Water-Freshwater
  Interfaces
          78:02F-008
                  Salton  Sea  (California)
                           78:04B-001
Salinity
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78;
          78;
          78s
          78:
          78
          78
          78
          78
          78
          78
          78
          78
          78
          78
 02G-014
 02G-G39
:02G-071
-.021-024
:02I-025
:02I-028
:02I-029
:03C-002
:03C-003
:03C-004
:03C-005
:03C-006
:03F-040
:04B-006
:05B-022
:05B-038
:05G-009
:05G-010
:05G-011
t05G-019
:05G-020
:05G-022
t05G-023
:05G-025
:05G-028
:05G-035
:05G-044
:05G-050
:05G-073
:05G-075
:06B-002
:06E-00€
:06G-003
-.07A-003
.-10C-001
Salinity Measurements
           78:020-071

Salinity Meter
           78:02G-071

Salinity Sensor
           78:02G-071

Salt Balance
           78:02G-039
           78:030006
           78:058-038
           78:05G-073

Salt Tolerance
           78:021-015
           78j03C-001
           78s03C-005
 Salt Water
           78:05G-011
 Saltation
                  Salts
          78:02G~004
          78:02G-010
          78:02G-012
          78:02K-015
          78:03C-004
          78:05B-012
          78:05B-038
          78-.05G-028
          78:05G-038
Sampling
          78:02K-Q66
          78:040-001
          78:05A-001
          78:05A-007
          78:05A-008
          78:05A-011
          78:05A-015
          78:05B-042
          78:07A-003
          78:078-001
          78:076-002
          78-.07B-005
          78:078-028
          78:07B-034

San Luis River Basin
   (California)
          78:050-016
Sands
          78:020-002
          78:02G-022
          78-.02G-062
          78:02J-005
          78:04A-018
          78s04B-010
          78s05B-005
                  Saprolites
                            78:02K-007

                  Saskatchewan River
                            78:02E-007

                  Saturated Flow
                            78.-02C-001
                            78s02F-006
                            78:02F-013
                            78:02F-028
                            78:02G-019
                            78:020-047
                            78:020-048
                            78:04B-011
                            78:04B-012
                            78:05B-019
                            78-.06A-009

                  Saturated Soils
                            78:020-024
                  Scaling
                                         78:020-043
           78:02J-017
           78:050-001
                  Scheduling
         78:020-
         78:021-
         78:03F-
         78:03F-
         78:03F-
         78:03F-
         78:03F-
         78:03F-
         78:03F-
         78:03F-
         78:04A-
         78s07A-
•008
•038
•033
•046
•049
•052
•068
•073
•077
•112
-016
-001
                              Scour
         78:02J-016
Seasonal
         78:02H-002
         78:02K-056
         78-.04A-008
                            78:020-007
Sediment
         78:05G-073

Sediment Control
         78:02J-006
         78j02J-007
         78:02J-008
         78:02J-009
         78:02J-010
         78-.02J-022
         78:02J-028
         78:04A-009
         78:04A-013
         78-.05G-003
         78:05G-038
         78:05G-048
         78:05G-058
         78:05G-060
         78:06A-016
         78:06B-011
         78-.06B-015
         78:06E-015
         78:08A-004

Sediment Discharge
         78:02J-004
         78:02J-008
         78:058-065
         78:Q5B-068
         78:05G-019
         78:056-064
         78:050-065
         78:06A-016

Sediment Distributions
         78-.02J-014
         78:02J-025
         78:07A-002

Sediment Load
         78:02J-003
         78:02J-007
         78.-02J-008
         78-.02J-010
         78:02J-015
         78:05B-068
         78:050-063
         78:050-072
         78:06E-015
         78:07A-002
                                     335

-------
 Sediment Sorting
           78:04D-002

 Sediment Sources
           78:02J-013

 Sediment Transport
           78:02J-005
           78:02J-013
           78:02J-014
           78:02J-017
           78:02J-019
           78:02J-022
           78:02J-024
           78:040-001
           78:04D-002
           78:058-068

 Sediment Yield
           78:02J-005
           78:02J-010
           78:02J-012
           78:02J-019
           78:02J-022
           78:050-037
           78:06A-008
           78:06A-015
           78:06E-015
           78:08A-004

 Sedimentation
           78:02J-014
           78:02J-024
           78:02J-026
           78:04C-001
           78:040-006
           78:05A-020
           78:05G-058
           78:088-013

 Sedimentation Rates
           78:040-005
Sediments
Seeds
          78:02J-007
          78:02J-008
          78:02J-009
          78:02J-010
          78:02J-013
          78:02J-014
          78:02J-015
          78:02J-025
          78:040-001
          78:040-002
          78:040-004
          78:040-005
          78:040-008
          78:058-003
          78:056-008
          78:058-028
          78:058-042
          78:058-044
          78:050-037
          78:050-038
          78:088-003
          78:020-029
          78:021-009
          78:021-011
Seepage
          78:02F-008
          78:02F-014
          78:02F-015
          78:02F-019
          78:03F-081
          78:04A-002
          78:04A-018
          78:058-022
          78:050-011
          78:06A-005
          78:080-001

Seepage Control
          78:02F-019
          78:04A-018
          78:06A-005
          78:080-001

Selectivity
          78:021-021
          78:02K-035
          78:02K-070

Self Purification
          78:058-034

Semiarid Climates
          78:038-001
          78:03F-041
          78:04A-009
          78:06E-003

Sensitivity Analysis
          78:02A-003

Sensitivity Coefficient
          78:02A-003

Septic Tanks
          78:058-004
          78s05B-052
Shales
          78:058-038
Sevin
Sewage
          78:058-040
          78:05C-006
Sewage Bacteria
          78:058-004

Sewage Disposal
          78:021-033
          78:02K-055
          78:058-052
          78:050-007

Sewage Effluent
          78:021-033
          78.-02K-055
          78:058-019
          78:058-052
          78:050-007

Sewage Slude
          78:021-010
          78:021-032
Shallow Water
          78:02F-021
          78:020-076

Shear Strength
          78:02J-002

Sheet Erosion
          78:02J-021
Sheet Flow
Silage
Silting
Silts
          78:02E-010
          78:03F-027
          78:02J-026
          78:020-061
          78:03F-035
          78:058-005

Simulated Analysis
          78:050-018
          78:050-064
          78:050-072

Simulated Rainfall
          78:02E-011
          78:020-066
          78:02J-025
          78:02J-027
          78:040-004
          78:050-029

Simulation Analysis
          78:02A-002
          78:02A-004
          78:02A-006
          78:02A-011
          78:02E-008
          78:02F-011
          78:02F-015
          78:020-015
          78:020-060
          78:021-004
          78:021-012
          78:021-020
          78:02J-005
          78:02J-009
          78:02J-012
          78:02J-017
          78:02J-019
          78:02J-024
          78:02K-005
          78:038-001
          78:03F-058
          78:048-007
          78:048-008
          78:058-018
          78:06A-003
          78:06A-006
          78:06A-014
          78:06A-015
                                      336

-------
Simulation Analysis
   (cont.)
          78:06B-020
          78:060-001
          78:088-004
Simulation
Sink
Sites
Size
Skimming
Slime
          78:06A-001
          78:021-008
          78:03F-023
          78:02J-025
          78:04D-008
          78:08A-004
          78:03F-090
Slope Stability
          78:04A-010
          78:04D-006
          78:04D-008

Slopes
          78:02F-010
          78:02F-014
          78:02J-005
          78:04A-010
          78:040-008
          78:06A-004

Small Watersheds
          78:02A-010
          78:02E-011
          78:02J-004
          78:04A-015
          78:05A-021
          78:05G-024
          78:06A-003
Snow
Snowmelt
          78:02K-044
          78:058-041
          78:02K-044
          78:058-044
          78:068-017
Snowpacks
          78:02K-044
Social Aspects
          78:03F-079
          78:03F-107
          78:05G-047
          78:05G-055
          78:068-010
          78:06G-002
          78:060-003

Social Impact
          78:03F-079
          78:06A-007
          78:06B-010
          78:06C-002

Social Participation
          78:03F-079
          78:050-055

Sodium
          78:020-004
          78:020-023
          78:02K-024
          78:02K-047
          78:02K-058
          78:050-036

Sodium Adsorption Ratio
          78:02J-002

Sodium Chloride"
          78:021-002
          78:058-005

Sodium Compounds
          78:02K-003
          78:078-010

Soil Aggregates
          78:02J-027

Soil Amendments
          78:021-010
          78:02K-031
          78:02K-033
          78:050-036  '

Soil Analysis
          78:020-023
          78:02K-021
          78:02K-045
          78:02K-055
          78:02K-064
          78:02K-069
          78:05A-011
          78:078-010
          78:078-019

Soil Bacteria
          78:05A-021

Soil Chemical Properties
          78:020-023
          78:020-030
          78:02G-037
          78:021-024
          78:02K-017
          78:02K-028
          78:02K-051
          78:02K-066
          78:02K-069
          78:02K-070
          78:07A-003
          78:078-004
          78:078-010
          78:078-014

Soil Chemistry
          78:020-005
          78:020-019
          78:020-037
          78:02K-008
          78:02K-009
          78:02K-010
          78:02K-013
          78:02K-014
          78:02K-021
          78:02K-023
          78:02K-028
          78:02K-030
          78:02K-034
          78:02K-036
          78:02K-039
          78:02K-059
          78:02K-062
          78:02K-063
          78:02K-065
          78:02K-066
          78:02K-068
          78:02K-070
          78:02K-073
          78:02K-074
          78:02K-075
          78:06A-001

Soil Classification
          78:03F-070

Soil Compaction
          78:078-022

Soil Conservation
          78:02E-011
          78:02J-001
          78:02J-006
          78:04A-010
          78:04C-001
          78:05G-024
          78:050-048
          78:050-049
          78:050-060
          78:050-061
          78:05G-065
          78:05G-068
          78:068-002
          78:068-011
          78:068-014
          78:06E-005
          78:06E-011
          78:06E-015

Soil Contamination
          78:02K-011
          78:05A-003
          78:05A-022
          78:058-004
          78:058-024
          78:058-026
          78:058-039
          78:058-055
          78:058-057
          78:058-058
          78:050-001

Soil Disposal Fields
          78:058-004

Soil Drainage
          78:050-034
                                  337

-------
 Soil  Environment
           78:02K-056
           78:05A-009
 Soil  Erosion
           78
           78
           78
           78:
           78:
           78;
           78;
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
           78:
:02A-010
:02J-004
:02J-007
:02J-008
:02J-012
:02J-015
:02J-018
:02J-020
:02J-021
:02J-024
:02J~025
:02J-026
:02J-027
:03F-070
:03P-072
:03F-113
:04A-017
:04C-001
:04D-001
:04D-004
:04D-007
:05B-003
:05B-007
:05B-008
:05B-065
:05G-037
:05G-043
:05G-058
(05G-059
 06B-014
 06B-015
 06E-002
 08A-004
Soil Formation
          78:02K-007

Soil Gases
          78:02K-056
          78:02K-057
          78:02K-061
          78:078-030
          78:07B-035

Soil Horizons
          78:02G-028
          78:020-040
          78:02K-050
          78.-07B-036

Soil Investigations
          78:03F-029

Soil Management
          78:02G-023
          78:02G-030
          78:02J-020
          78:02K-039
          78:03F-018
          78:03F-108
          78:040-007
          78.-05A-009

Soil Microbiology
          78:02K-042
           78:050-002

 Soil Moisture
           78:02A-009
           78:020-007
           78:02G-018
           78:02G-031
           78:02G-038
           78:02G-040
           78:02G-052
           78.-02G-063
           78:02G-071
           78:02G-073
           78:02G-074
           78:02G-075
           78:02G-084
           78:02G-085
           78:021-041
           78:02K-005
           78:02K-061
           78:033-001
           78-.03F-025
           78:03F-028
           78:03F-033
           78:03F-039
           78.-03F-095
           78.-03F-112
           78:03F-118
           78:05A-009
           78:068-005
           78:060-002
           78:078-017
           78:076-034

Soil Moisture Movement
           78:02A-007
           78:02D-005

Soil Moisture Sensor
           78:02G-071

Soil Morphology
           78:04D-006

Soil Physical Properties
           78:02G-019
           78:02G-030
           78:02G-034
           78:02G-037
           78:02G-060
           78:02G-073
           78:02K-017
           78;02K-020
           78:03F-070

Soil Physics
           78:02G-053
           78:02G-054

Soil Profiles
           78-.Q2G-050
           78:020-057
           78:021-008
           78-.02K-003
           78:02K-035

Soil Properties
          78:02A-009
          78:020-005
           78:02F-002
           78.-02G-057
           78:02G-068
           78:02G-074
           78:02G-081
           78:021-003
           78:021-005
           78:021-012
           78:05G-037
           78:07B-017

 Soil  Radiation
           78:020-001
           78:020-006

 Soil  Sampling
           78:05A-011

 Soil  Sampling Procedure
           78:05A-011

 Soil  Science
           78:02G-001
           78:02G-011
           78:02G-014
           78:02G-027
           78:02G-063
           78:02G-081
           78.-02K-023

 Soil  Strength
           78:040-006

 Soil  Surface
           78:02G-031

 Soil  Temperature
           78:02G-031
           78:02K-061
           78:03F-025
           78:05A-022
           78:076-033

 Soil  Tests
           78:021-005
           78:02K-028
           78:02K-045
           78:02K-051
           78:02K-069
           78-.02K-075
           78:03F-003
           78:078-003
           78:076-004
           78:07B-010
           78:078-012
           78:078-017
           78:078-019
           78.-07B-024
           78.-08G-002

Soil Texture
           78:02G-042
           78:02G-079
           78:02J-027
          78-.02K-050
          78:03F-060
          78:048-009

Soil Treatment
          78:02F-002
                                     338

-------
Soil Types
          78:02G-028
          78:02G-041
          78:02G-055
          78:02J-002
          78:02K-018
          78:058-005
          78:078-001
Soil Water
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
          78:
02C-001
02D-008
02G-001
02G-003
02G-006
02G-008
02G-009
02G-010
02G-011
02G-012
02G-016
02G-025
02G-027
02G-028
02G-041
02G-044
02G-052
02G-054
02G-055
02G-059
02G-066
02G-075
026-079
020-080
02G-084
020-085
;02G-086
;02K-028
;03F-021
:04A-005
:04B-008
;05B-018
:06A-001
:07B-017
;07B-022
:07B-036
Soil Water Movement
          78:02A-010
          78:020-001
          78:02G-002
          78:02G-003
          78:02G-006
          78:02G-007
          78:02G-009
          78:02G-010
          78:02G-012
          78:026-015
          78:026-016
          78:026-017
          78:026-019
          78:026-022
          78:026-025
          78:02G-027
          78:026-028
          78:02G-041
          78:02G-045
          78:026-046
          78:026-047
          78:026-049
          78:026-050
          78:02G-052
          78:020-053
          78:02G-054
          78:020-055
          78:020-059
          78:02G-060
          78:020-061
          78:020-062
          78:020-063
          78:020-065
          78:020-066
          78:020-067
          78:020-068
          78:020-072
          78:020-076
          78:020-077
          78:020-078
          78:020-081
          78:020-084
          78:020-085
          78:020-086
          78:021-008
          78:02K-024
          78:03F-013
          78:04A-005
          78:05B-018
          78:05B-039
          78:056-034
          78:06A-009

Soil-Water-Plant
   Relationships
          78:02A-007
          78:02A-008
          78:026-074
          75:021-002
          78:021-006
          78:021-008
          78:021-015
          78:021-031
          78:021-036
          78:03C-003
          78:03F-008
          78:03F-021
          78:03F-056
          78:03F-109
          78:048-008

Soil-Water Retention
          78:026-079
                 Soils
                           78:02E-010
                           78:02F-019
                           78:02F-028
                           78:026-002
                           78:026-003
                           78:020-004
                           78:026-008
                           78:026-010
                           78:026-018
                           78:026-022
                           78:026-027
                           78:026-028
                           78:026-040
                           78:026-041
                           78:026-055
                           78:026-062
                           78:026-079
                           78:020-081

                             339
         78:02J-001
         78:02J-002
         78:04A-002
         78:04A-018
         78:040-001
         78:040-002
         78:040-008
         78:058-003

Solubility
         78:021-017
         78:02K-012
         78:02K-013

Soluble Nutrients
         78:050-037
Solute
Solutes
         78:020-009
         78:02G-006
         78:020-008
         78:020-012
         78:020-013
         78:020-015
         78:020-019
         78:020-020
         78:020-040
         78:020-046
         78:020-065
         78:020-077
         78:020-078
         78:021-013
         78:02K-024
         78:02K-062
         78:058-013
         78:05B-062

Solvent Extractions
         78:07B-018
Sorghum
         78:020-046
         78:021-003
         78:03F-051
         78:03F-095
         78:07B-012

Sorption
         78:026-022
         78:026-056
         78:02K-015
         78:040-001
         78:05B-028
         78:058-033
         78:058-034
         78:078-016

South Carolina
         78:040-006

South Dakota
         78:021-016

Southeast United States
         78:03F-061
         78:03F-078

-------
Soybeans
          78:026-026
          78:021-001
          78:021-009
          78:021-010
          78:021-036
          78:03F-001
          78:03F-021
          78:03F-051
          78:048-005
          78:056-001
          78:05G-007
          78:05G-029
          78:05G-043

Spatial Distribution
          78:02F-023
          78:02J-014
          78:03F-126
          78:07A-003

Specific Yield
          78:02F-027
          78:026-042

Specifications
          78:03F-043
          78:08A-004

Spectrometers
          78:02K-059

Spectrophotometry
          78:078-012
          78:078-018

Spectroscopy
          78:02K-030

Spoil Banks
          78:05G-001

Sprinkler Irrigation
          78:02G-044
          78:021-041
          78:03F-007
          78:03F-020
          78:03F-030
          78:03F-040
          78:03F-041
          78:03F-044
          78:03F-045
          78:03F-047
          78:03F-058
          78:03F-063
          78:03F-064
          78:03F-065
          78:03F-069
          78:03F-070
          78:03F-071
          78:03F-072
          78:03F-074
          78:03F-075
          78:03F-076
          78:03F-077
          78:03F-078
          78:03F-081
          78:03F-084
          78:03F-085
          78:03F-091
          78:03F-092
          78:03F-097
          78:03F-098
          78:03F-102
          78:03F-103
          78:03F-104
          78:03F-105
          78:03F-114
          78:03F-126
          78:048-014
          78:05A-002
          78:058-011
          78:058-022
          78:05G-002
          78:05G-010
          78:06A-007
          78:068-007
Stability
          78:020-002
          78:026-014
          78:02J-011

Stabilization
          78:02J-011

Stable Isotopes
          78:026-051
          78:02K-001
          78:02K-006

State Governments
          78:056-068

State Space Formulation
          78:02A-006

Statistical Methods
          78:020-007
          78:02F-025
          78:026-074
          78:03F-030
          78:03F-064
          78:03F-065
          78:03F-105
          78.-04A-015
          78:048-009
          78:05A-008
          78:05A-015
          78:056-046
          78:07A-003

Statistical Models
          78:02A-001
          78:028-001
          78:02E-002
          78:02F-007
          78:026-018
          78:026-042
          78:05A-007
Statistics
          78:020-001
          78:02E-002
          78:02F-011
          78:05A-007
          78:060-001
Steady Flow
          78:02F-010
          78:02F-017
          78:02F-018
          78:026-007
          78:026-047
          78:026-050
          78:026-054
          78:026-064
          78:02G-077
          78:02G-078
          78:03F-110
          78:058-017
          78:058-059
          78:06A-005
Stemflow
          78:021-020
Stochastic Models
          78:02J-013

Stochastic Processes
          78:02A-007
          78:02A-010
          78:028-001
          78:020-001
          78:02E-002
          78:02E-004
          78:02E-005
          78:02E-007
          78:02E-008
          78:02E-009
          78:02F-007
          78:02F-013
          78:02F-023
          78:02F-025
          78:026-074
          78:02J-013
          78:04A-001
          78:04A-004
          78:04A-008
          78:08E-001
Stomata
          78:021-015
Storage Capacity
          78:02F-020
          78:04A-008

Storage Coefficient
          78:02A-003

Storm Runoff
          78:02.A-007
          78:02A-009
          78:040-005
          78:058-006
          78:058-014
          78:06A-015
          78:068-020

Storms
          78:028-001
          78:02E-002
          78:04A-008

Stratification
          78:026-075
                                     340

-------
 Stratified Flow
           78:02G-007

 Strawberries
           78:03F-074

 Stream Erosion
           78:02J-011
           78:02J-028

 Stream Gages
           78:073-032

 Stream Response
           78:05G-031
Streamflow
           78:02A-011
           78:02E-001
           78:02E-003
           78:02E-004
           78:02E-005
           78:02E-008
           78:02J-008
           78:058-065
           78:06A-014
           78:07A-002
Streams
          78:020-001
          78:02E-005
          78:04A-001
          78:05A-007
          78:05B-042
          78:058-049
          78:05B-064

Strip Mine Wastes
          78:05G-001

Structural Models
          78:02K-030

Structures
          78:050-028

Subcritical Flow
          78:086-002

Submerged Plants
          78:021-037
          78:02K-043
          78:03F-006
          78:06A-006

Submerged Vegetation Stage
          78:06A-006

Submergence
          78:02G-035
          78:02G-036
          78:058-056
          78:06A-006

Subsurface Drainage
          78:02G-057
          78:02G-058
          78:02J-019
          78:02K-052
          78:03F-124
           78:04A-015
           78:048-005
           78:048-006
           78:048-007
           78:048-009
           78:05G-018
           78:05G-023
           78:050-026
           78:06A-004
           78:06A-005
           78:08A-002
           78:08G-002
           78:08G-003

 Subsurface Drains
           78:02F-028
           78:020-058
           78:02K-052
           78:048-005
           78:048-006
           78:048-009
           78:06A-004
           78:06A-005
           78:06C-001
           78:08A-002
           78:08G-002
           78:08G-003

 Subsurface Flow
           78:02F-007
           78:02F-023
           78:048-012
           78:058-012
           78:058-052
           78:06A-009

 Subsurface Irrigation
           78:03F-063
           78:058-011

 Subsurface Runoff
           78:04A-015
           78:058-034

 Sudangrass
           78:021-007

 Sugar Beets
           78:021-030
           78:03F-028
           78:03F-125
 Sulfur
           78:021-017
           78:02K-031
Sugarcane
Sulfates
          78:030-002
          78:03F-089
          78:02K-013
          78:02K-015
          78:02K-028
          78:02K-030
          78:02K-073
Sulfides
          78:02K-013
Sulfonates
          78:050-001
 Sulfur Compounds
           78:03F-029

 Supplemental  Irrigation
           78:021-001
           78:021-026
           78:03F-001

 Surface Drainage
           78:04A-015
           78:048-007
           78:050-018
           78:050-023

 Surface Irrigation
           78:03F-034
           78:03F-047
           78:03F-054
           78:03F-063
           78:03F-081
           78:03F-083
           78:03F-084
           78:03F-085
           78:03F-086
           78:03F-096
           78:03F-100
           78:03F-115
           78:03F-116
           78:03F-128
           78:04A-007
           78:04A-013
           78:04D-008

 Surface  Runoff
           78:02A-005
           78:02A-008
           78:020-005
           78:02E-010
           78:02E-011
           78:020-058
           78:02J-004
           78:02J-010
           78:02J-012
           78:02J-018
           78:04A-012
           78:04A-013
           78:04A-015
           78:04A-017
           78:058-007
           78:058-008
           78:058-023
           78:058-024
           78:058-034
           78:058-037
           78:058-044
           78:050-030
           78:088-007
           78:100003

Surface Runoff Plots
          78:05A-011

Surface Sealing
          78:02J-027
                                      341

-------
Surface Water Runoff
          78:040-003

Surface Waters
          78:05A-021
          78.-05G-034

Surface-Groundwater
  Relationships
          78;02F-015
          78:058-002
          78:05G-031
          78:05G-033
                                                           Thawing
          78.-02G-020
Surveys
          78-.05A-001
          78.-05B-042
Suspended Load
          78.-02J-003
          78:02J-004
          78:02J-013
          78:020-018

Suspended Solids
          78.-04D-001
          78:086-013
Suspension
          78:02J-018
          78-.02K-012
          78:02K~073

Sweet Corn
          78:021-020
          78:021-021
          78:02K-023
          78.-03P-D25
          78:037-027
          78:03F-031
          78:03F-033
          78:03F-056
          78:03F-073
          78:05A-004
          78:05B-025
          78:05G-021
          78:076-012

Swimming Facilities
          78:05A-015

Symbiosis
          78.-020-026
          78-.05G-007
          78:976-006

Synthetic Hydrology
          78:02A-005
          78.-02E-001
          78-.02E-002
          78:02E-007

Synthetic Models
          78.-02J-013

systemics
          78:02K-025

Systems Analysis
          78:03F-095
          78:056-009
          78:05G-003
          78:05G-004
Tailwater
          78:03F-035
          78:03F-106
          78.-03F-123
          78:04A-013
Techniques
          78:07B-002
Technology
          78-.02A-001

Temperature
          78:02F-021
          78:02G-031
          78:021-011
          78:021-013
          78:02J-002
          78s02K-012
          78:02K-038
          78:053-015

Temperature Profile
          78:02H-002

Tensiometers
          78:02G-011
          78:02G-025
          78:02G-076
          78:021-038
          78:03F-001
          78:03F-039
          78:07A-001

Tension Lysimeter
          78:02G-005
Terracing
Testing
          78:02J-006
          78:04A-009
          78-.04A-010
          78:068-012
          78:02F-001
          78:03F-058
          78:03F-091
Testing Procedures
          78:02J-002
          78:03F-091
Texas
          78:02D-004
          78.-03F-047
          78-.04A-010
          78:048-006
          78.-04D-005
          7fi:05B-023
          78:058-024
          78:055-026
          78:05C-001
          78:068-015
          7BJ06E-003
Texas Water Plan
          78:020-004

          342
Theoretical Analysis
          78:02F-004
          78:02F-009
          78-.Q2G-Q04
          78.-02G-006
          78.-02G-036
          78:026-042
          78:02G-048
          78:02G-063
          78:02G-077
          78:02G-080
          78:05B-039
          78:08B-013

Thermal Conductivity
          78:02G-020

Thermal Pollution
          78:058-015
          78:05G-031

Thermal Powerplants
          78:048-001

Thermal Radiation
          76:020-006

Thermal Stratification
          78:02H-002

Thermocline
          78:02C-001

Thermoclynamic Behavior
          78:02K-047

Thermodynamics
       \   78.-02K-035

Three-Dimensional
  Simulation Analysis
          78-.02F-015

Throughfall
          78:05A-012

Tile Drainage
          7S:02G-065
          78t02J-019
          78:02J-026
          7B:03F-124
          78:04A-005
          78:05A-004
          78:056-021
          78.-05G-025

Tile Drains
          78:02J-026
          78.-04A-005
Tiles
Till
          78:03F-130
                                       78t02E-011
                                       78:03F-108

-------
 Time
 Time Lag
           78:020-082
           78:02K-012
           78:02K-038
           78:03F-099
           78:03F-100
 Time  Series  Analysis
           78:02E-004
           78:02E-007
           78:02E-008
           78:02E-009
           78:04A-008
 Timing
Tobacco
Tomato
Tomatoes
Toxicity
           78:021-030
           78:02f(-005
           78:02K-018
           78:03F-049
           78:03F-051
           78:03F-115
           78:03F-118
           78:05G-070
           78:068-009
           78:021-002
           78:021-017
           78:02K-019
           78:058-043
          78:03F-007
          78:030005
          78:03F-074
          78:058-040
          78:021-010
          78:021-024
          78:02K-027
Trace Elements
          78:021-010
          78:021-032
          78:02K-059
          78:02K-064
          78:05A-005
          78:058-042

Tracers
          78:020-066
          78:021-030
          78:058-052

Trafficability
          78:048-007

Transient Flow System
          78:058-060

Transition Flow
          78:088-002

Translocation
          78:021-014
           78:021-018
           78:03F-022

 Transmissivity
           78:02A-003

 Transpiration
           78:02A-011
           78:021-015
           78:021-019
           78:021-031

 Transpriation Dispersion
           78:02G-062

 Trap Efficiency
           78:02J-028
           78:08A-004

 Travel Time
           78:02G-045
           78.-02G-065
           78:02G-077
           78:02G-078
           78:058-021
           78:058-062
 Turgidity
Treatment
Trees
Trenches
          78:03F-050
          78:058-041
          78:048-006
          78:050-026
          78:060001
          78:08A-002

Tributaries
          78:058-001
Trickling
                              Tritium
          78:03F-087
          78:02G-040
Tropic Level
          78:050006
          78:050007
Tubes
          78:08G-002
          78:08G-003
Turbulence
          78:02J-014
          78:058-015
          78:058-061

Turbulent Energy Flux
          78:020-002

Turf Grasses
          78:03F-003
          78:05A-002
          78:053-011
                                                           Turnouts
           78:021-015
           78:021-031
          78:03F-128
Unconsolidated Sediments
          78:02J-003

Underground Storage
          78:048-013

Uniform Flow
          78:058-013
          78:058-017

Uniformity
          78:03F-030
          78:03F-058
          78:03F-064
          78:03F-071
          78:03F-072
          78:03F-076
          78:03F-081
          78:03F-097
          78:03F-102
          78:03F-104
          78:03F-105
          78:03F-127
          78:068-005

Unit Hydrographs
          78.-02J-004

Unsaturated Flow
          78:02F-006
          78:02G-004
          78:026-009
          78:02G-012
          78:02G-015
          78:02G-017
          78:02G-018
          78:02G-024
          78:02G-042
          78:02G-043
          78:02G-047
          78:02G-048
          78:02G-053
          78:02G-054
          78:020-061
          78:02G-062
          78:020-085
          78:02G-086
          78:02K-062
          78:03F-093
          78:048-011
          78:048-012
          78:C6A-009

Unsaturated Soil
          78:02G-002

Unsteady Flow
          78:02E-003
          78:02F-009
          78:020-007
          78:02G-012
                                         343

-------
 Unsteady Flow
    (cont.)
           78:02G-061
           78:02G-086

 Unsteady Rain
           78:02G-052

 Urbanization
           78:05B-055

 Urea Pesticides
           78.-05B-026
 Ureas
 Utah
           78:021-007
           78:021-009
           78:02K-001
           78-.03F-029
           78:03P-057
           78:058-049
           78:078-003
           78:058-010
           78:056-038
 Vadose Water
           78:02P-027

 Valves
           78:020-011
           78:03F-053
           78:03F-117
           78:088-003

 Vapor  Pressure
           78;02D-006

 Variance Reduction
           78:02E-001

 Variability
           78:02G-028
           78:03C-001
           78:03F-087
           78:03F-105

 Varieties
           78:021-010
           78:030001
           78:03F-022
           78:03F-028

Vectors (Biological)
           78.-06G-001

Vegetable Crops
           78:03F-010
Vegetables
          78:053-040
Vegetation
          78:02A-009
          78:020-005
          78t02E~010
          78:020-068
          78:020-074
          78:03D-001
          78:058-012
 Vegetation Effects
           78:02D-004
           78.-02J-022
           78.-05A-009
 Velocity
           78:02J-016
 Vibrations
           78:02J-016
           78:08B-007

 Viscous Flow
           78.-02H-001
 Voids
           78:078-019
 Volatility
           78:021-033
           78:02K-033
           78:02K-040
           78.-02K-043
           78:02K-055
           78:03F-017
           78:03F-029
           78:03F-057
           78.-05A-022
           78:058-030

 Volumetric Analysis
           78:078-022

 Washington
           78:058-049
           78:05G-066
           78:06A-007
           78:060002
           78:06E-013

 Waste  Disposal
           78:03P-016
           78:053-020
           78:058-027
           78:058-050
           78:058-052
           78:05G-019

 Waste  Treatment
           78:058-009
           78:050-059

 Waste  Water
           78:050-006

 Waste  Water Disposal
           78:058-047
           78:06E-004

 Waste  Water Pollution
           78:058-047
           78:100006

 Waste Water Treatment
           78:056-005
           78:06E-004
           78:100006
Wastes
          78:05A-017
                                       344
Water
           78:05A-019
           78:058-019
           78:058-039
           78:05G-071
           78:06A-016
                                        78:06A-001
Water  Allocation
    (Applied)
           78:04A-003

Water  Allocation
    (Policy)
           78:05G-033

Water  Analysis
           78:02K-023
           78:03F-032
           78:05A-008
           78:05A-015

Water  Balance
           78:02A-007
           78:02A-008
           78:020-005
           78:02G-038
           78.-02G-068
           78:02G-074
           78:021-037
           78:03F-056
           78j03F-109
           78.-03F-123

Water  Chemistry
           78:02K-023
           78:02K-044
           78.-05A-010

Water  Conservation
           78:02J-006
           78:038-001
           78:03D-001
           78:03F-007
           78:03P-026
           78:03F-033
           78:03F-034
           78:03F-035
           78:03F-039
          78:03F-041
          78:03F-043
          78.-03F-044
          78:03F-045
          78:03F-046
          78:0.3F-047
          78:03F-048
          78.-03P-049
          78:03P-050
          78:03P-051
          78:03P-052
          78:03F-053
          78.-03F-055
          78s03F-Q€4
          78:03P-079
          78:03F-080
          78:03F-088
          78s03F-093
          78:03F-106
          78i03F-107

-------
Water Conservation
   (cont.)
          78:03F-110
          78:03F-118
          78:03F-127
          78:04A-010
          78:05G-049
          78:05G-065
          78:05G-068
          78:06E-011

Water Consumption
          78:02F-005

Water Costs
          78:03F-092
          78:03F-107
          78:05G-016

Water Delivery
          78:03F-107

Water Demand
          78:04A-008
          78:05G-016
          78:060-001
          78:060-002
          78:10C-005

Water Distribution
          78:058-022
          78:05G-011

Water Distribution
    (Applied)
          78:03F-034
          78:03F-092
          78:03F-103
          78:03F-127

Water Harvesting
          78:03F-123

Water Hyacinth
          78:020-004

Water Injury
          78:03F-096
Water  Law
           78:03F-107
           78:043-004
           78:05G-005
           78:05G-012
           78:05G-013
           78:05G~014
           78:05G-015
           78:05G-024
           78:05G-048
           78:05G-059
           78:050-073
           78:06A-007
           78:06B-011
           78:06E-001
           78:06E-003
           78:06E-004
           78:06E-007
           78:06E-009
           78:06E-010
           78:06E-020
Water Levels
          78:02F-012
          78:078-025

Water Level Fluctuations
          78:078-025

Water Level Recorders
          78:078-025

Water Loss
          78:020-004
          78:04A-013
          78:058-022
          78:05G-009

Water Management (Applied)
          78:02G-076
          78:021-027
          78:021-034
          78:021-037
          78:021-040
          78:021-042
          78:02K-065
          78:03F-001
          78:03F-008
          78:03F-045
          78:03F-046
          78:03F-048
          78:03F-052
          78:03F-059
          78:03F-060
          78:03F-061
          78:03F-062
          78:03F-069
          78:03F-071
          78:03F-073
          78:03F-080
          78:03F-107
          78:03F-112
          78:04A-001
          78:04A-004
          78:04A-01L3
          78:048-004
          78:048-008
          78:04C-001
          78:058-020
          78:05G-005
          78:050-028
          78:05G-035
          78:050-039.
          78:056-042
          78:05G-044
          78:05G-045
          78:05G-047
          78:05G-048
          78:05G-055
          78:05G-060
          78:05G-068
          78:05G-071
          78:05G-077
          78:06A-013
          78:068-009
          78:06E-011
          78:06E-020
          78:066-001
          78:06G-003
          78:10A-001
          78:10C-005
          78:10C-006
Water Management
          78:03F-015

Water Policy
          78:03F-079
          78:04A-003
          78:05G-055

Water Pollution
          78:021-030
          78:02J-003
          78:02J-020
          78:02J-022
          78:02J-027
          78:02K-048
          78:02K-049
          78:02K-053
          78:02K-061
          78:02K-064
          78:03F-015
          78:04A-016
          78:040-008
          78:05A-001
          78:05A-004
          78:05A-016
          78:05A-017
          78:05A-018
          78:05A-019
          78:05A-020
          78:058-001
          78:058-007
          78:058-010
          78:058-016
          78:058-022
          78:058-030
          78:058-031
          78:058-032
          78:058-034
          78:058-035
          78:058-037
          78:058-038
          78:058-039
          78:058-040
          78:058-041
          78:058-042
          78:058-046
          78:058-047
          78:058-052
          78:058-056
          78:058-057
          78:058-058
          78:058-059
          78:058-060
          78:058-064
          78:058-067
          78:058-068
          78:05C-006
          78:050-009
          78:05G-012
          78:050-013
          78:050-014
          78:050-015
          78:050-016
          78:050-018
          78:050-019
          78:050-020
          78:050-033
          78:050-037
          78:050-042
          78:05G-043
                                        345

-------
Water  Pollution
    (cont.)
           78:05G-045
           78:05G-046
           78:05G-049
           78:050-050
           78:05G-055
           78:050-059
           78:050-060
           78:05G-061
           78:050-063
           78:050-064
           78:050-065
           78:050-066
           78:050-067
           78:050-070
           78:050-071
           78:050-072
           78:050-073
           78:050-074
           78:050-075
           78:050-076
           78:050-077
           78:06A-001
           78.-06A-016
           78:068-010
           78:068-014
           78:066-015
           78:06B-017
           78:06B-019
           78:06B-020
           78:06E-001
           78:06E-002
           78.-06E-004
           78.-06E-005
           78:06E-009
           78:06E-010
           78:06E-011
           78:06E-013
           78:06E-014
           78:06E-020
           78:060-001
           78:076-026
           78.-10C-002
           78.-10C-003
           78:100-006

Water Pollution Control
           78:03F-032
           78:05A-019
           78:058-009
           78:058-030
           78:058-065
           78:050-003
           78:050-004
           78:056-019
           78:050-021
           78:05G-022
           78:050-039
           78:050-043
           78:050-047
           78:050-048
           78:050-049
           78:050-050
           78:050-055
           78:050-058
           78:050-059
           78:050-060
           78:050-061
           78:050-062
           78:050-063
           78;Q5G-064
           78:050-066
           78:050-068
           78:050-069
           78:050-071
           78:050-073
           78:05G-074
           78:050-077
           78:068-010
           78:06B-014
           78:06B-015
           78:06E-004
           78:06E-005
           78:06E-006
           78:06E-009
           78:06E-010
           78.-06E-013
           78:06E-020
           78:100-002

Water Pollution Effects
           78:058-002

Water Pollution Sources
           78:05A-017
           78:05A-022
           78:058-002
           78:058-004
           78:058-014
           78:058-017
           78:058-026
           78:058-031
           78:058-041
           78:058-057
           78:058-058
           78:058-062
           78:058-065
           78:056-067
           78:058-068
           78:050-019
           78:050-022
           78:050-037
           78:050-047
           78:050-048
           78:050-049
           78:050-051
           78:050-061
           78:050-062
           78:068-012
           78:06E-004
           78:06E-005
           78:06E-013
           78:078-026

Water Pressure
           78:020-085
           78:021-004
           78:021-031
          78:03F-058
          78:03F-097
          78:03F-127
          78:048-014
          78:088-004
          78:088-006

Water Properties
          78s05B-007
                                       346
Water Quality
          78:02A-004
          78:020-039
          78:020-077
          78:021-002
          78:02J-003
          78:02J-006
          78:02J-015
          78:02J-024
          78:03C-003
          78:03C-006
          78.-03F-014
          78.-03F-032
          78:048-004
          78-.05A-001
          78:05A-007
          78:05A-008
          78:05A-016
          78:05A-017
          78:05A-018
          78:05A-020
          78:05A-021
          78:058-006
          78:058-008
          78:058-010
          78:058-014
          78:058-021
          78:058-022
          78:058-024
          78:058-025
          73:058-026
          78:058-030
          78:058-031
          78:058-032
          78:058-037
          78:058-038
          78:058-039
          78:058-040
          78:058-044
          78:058-046
          78:058-048
          78:058-049
          78:058-064
          78:058-068
          78:05C-007
          78:050-005
          78:050-008
          78:050-009
          78:050-010
          78:050-012
          78:050-013
          78:050-014
          78:050-015
          78:050-016
          78:050-018
          78:050-019
          78:050-024
          78:050-025
          78:050-029
          78:050-030
          78:050-031
          78:050-033
          78:050-035
          78:050-037
          78:050-039
          78:050-042
          78:050-044
          78:050-046
          78:050-047
          78:050-048
          78:050-049

-------
 Water Quality
    (cent.)
           7B:05G-050
           78:050-055
           78:050-059
           78:05G-060
           78:05G-061
           78:05G-062
           78:05G-063
           78:05G-064
           78:05G-065
           78:05G-066
           78:05G-067
           78:05G-069
           7B:05G-070
           78:05G-071
           78:05G-073
           78:05G-075
           78:05G-076
           78:05G-G77
           78:C6A-001
           78:06A-008
           78:06A-014
           78:06B-001
           78:063-002
           73:068-014
           78:06B-01S
           78:06B-017
           78:06B-019
           78:066-020
           78.-06E-001
           78.-06E-006
           78:06E-009
           78:06E-010
           78:06E-0.13
           78:06E-014
           7S:06E-015
           78:06E-020
           78:07A-003
          78:073-026
          78:10A-001
          78:10C-003
          78:100-0.06

Water Quality Act
          78.-05G-022
          78:05G-048
          78:05G-049
          78:05G-050
          78:056-062
          78:05G-068
          78:050-069
          78:05G-071
          78:06E-004
          78:06E-005
          7B:06E-006
          78:06E-010
          78:06E-014
          78:100006

Water Quality Control
          78:02A-004
          78:048-006
          78:05A-018
          78J05A-019
          78:053-002
          78:»5G-C19
          78:05G-020
          78:05G-022
          78:05G-024
           78:05G-039
           78:05G-043
           78:05G-049
           78:05G-050
           78:05G-051
           78:055-055
           78.-05G-058
           78:050-060
           78:05G-061
           78:05G-062
           78-.05G-066
           78:05G-067
           78:050-068
           78:050-069
           78:05G-070
           78:05G-071
           78-.05G-075
           78:050-076
           78:06B-010
           7B:06B-014
           78.-06S-015
           78:063-019
           7S:06E-004
           78:06E-009
           78:06E-010
           78:06E-011
           78:06E-013
          •78J06E-014
           78:06E-020
           78:100-006

Water  Quality  Standards
           78.-05A-015

Water  Requirements
           78:02G-076
           78:021-003
           78:021-034
           78:021-036
           78:021-037
           78:021-038
           78:021-040
           78:021-041
           78:021-042
           7B:03D-001
           78.-03F-031
           78:048-001
           78.-06D-002

Water  Resources
           78:02A-002
           7B:02F-018
           78:046-001
           78:05B-017
           78:06A-001
           78:06A-010

Water  Resources Development
           78:06A-010
          78.-06C-002

Water  Resources Planning
   Act
          78:06E-004

Water  Reuse
          78:046-014

Water  Rights
          7B:04B-004
           78:05G-012
           78:05G-013
           78:05G-014
           78:050-015
           78:06E-001
           78.-06E-003
           78.-06E-007

 Water Sampling
           78.-05B-002
           78:07B-026

 Watershed  Management
           78:02A-011
           78:02J-022
           78:05G-002
           78:05G-065
           78:06A-015

 Watersheds (Basins)
           78:02A-005
           78:02F-011
           78:02J-005
           78:040-001
           78:04D-005
           78-rt)5B-023

 Water  Shortage
           18:03P-035
           7&:03P-041
           78:03P-053
           78:03P-058
           78:03P-077
           78:03F-080
           7Bs03P-088

 Water  storage
           78:048-004
           78:048-013
           78:06E-007
           78:078-022

 Water  Supply
           78:043-001
           7S:06E-007
           78:083-010

 Water  Table
           78:02P-020
           78:02G-003
           78:02G-038
           78:02G-057
           78:020-081
           78?03F-125
           78:04B-002
           78:04B-008
           78:04B-009
           78:058-035
           78:05G-002
           78:05G-025
           78:06A-004
           78:06A-005

Water  Table Aquifers
           73.-02F-017
           78:02F-027
           78:02F-028
                                       347

-------
Water Temperature
          78:020-001
          78:02E-005
          78:050-031

Water Transfer
          78:05G-033

Water Treatment
          78:03F-032
          78.-05G-038

Water Tunnels
          78:088-007

Water Utilization
          78:03D-001
          78.-03F-009
          78:06E-003

Water Wells
          78:02F-016
          78:05A-010
          78.-05B-039
          78:05B-062

Water Yield
          78:02A-007
          78:02J-019
          78:04A-006
          78:04A-012
          78:06A-015
          78:076-026

Wave Velocity
          78:02A-002

Waves (Water)
          78:086-001
          78:08B-012

Weather Data
          78:02A-001
          78:021-035

Weathering
          78:02K-007

Weed Control
          78:02K-016
          78:03F-108
          78:056-006
          78:056-023
          78:056-029
Weeds
          78:02K-016
Well Casings
          78:058-062

Well Contamination
          78:058-039
Well Data
Wells
          78:03F-017
          78:02F-016
          78:04A-001
          78:048-010
          78:056-016
          78:058-039
          78:068-009
                                                            Yolo Loam
Wetting
          78:02G-001
          78:02G-022
          78:020-030
          78:02G-067
          78:02G-080
          78:02G-084
          78:056-001

Wetting Front
          78.-02G-034
Wheat
Wiers
          78:020-046
          78:020-076
          78:021-008
          78:021-026
          78:030-001
          78:03F-002
          78:03F-022
          78:03F-024
          78:04A-012
          78:05B-044
          78:050-021
          78:076-005
          78:078-007
          78:086-009
Wind Erosion
          78:02J-021
          78:040-007

Wind Velocity
          78:03F-076
Wisconsin
          78:02G-028
Withdrawal
X-Ray
Xylem
          78:02H-001
          78:02K-013
          78:02K-073
          78:021-004
          78:021-015
Zinc
          78:02J-002
          78:021-032
          78:02K-010
          78:02K-013
          78.-02K-027
          78:02K-072
          78:03F-006
          78:03F-025
          78:058-055
Yakima Valley (Washington)
          78:0"5G-033

Yield Equation
          78:021-003
          78:021-036
          78:021-040
          78:021-041
          78:021-042
          78:03F-031
          78:03F-048
          78:03F-062
          78:03F-092
          78:066-021
                                      348

-------
                              TECHNICAL REPORT DATA
                        (Please read Instructions on the reverse before completing)
 1. REPORT NO.

  EPA-600/2-80-073
           3. RECIPIENT'S ACCESSIONING.
 4. TITLE AND SUBTITLE
  SELECTED IRRIGATION RETURN FLOW QUALITY
  ABSTRACTS 1978,  Eighth Annual Issue
           5. REPO'RT DATE
            April 1980 issuing date
           6. PERFORMING ORGANIZATION CODE
'7. AUTHOR
-------