United States
Environmental Protection
Agency
Robert S. Kerr EPA-600/2-78-042
Environmental Research Laboratory March 1978
Ada OK 74820
Research and Development
&EPA
Selected Irrigation
Return Flow Quality
Abstracts 1976
Sixth Annual Issue
-------
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.
-------
EPA-600/2-78-042
March 1978
SELECTED IRRIGATION RETURN FLOW
QUALITY ABSTRACTS 1976
Sixth Annual Issue
by
Gaylord V. Skogerboe
Stephen W. Smith
Wynn R. Walker
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
-------
DISCLAIMER
This report has been reviewed by the Office of Research
and Development, U.S. Environmental TProtection 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.
-------
FOREWORD
The Environmental Protection Agency was established to
coordinate 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 tech-
niques 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 research facilities.
As one of these facilities, the Robert S. Kerr Environmental
Research 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 contributes to the knowledge essential if the
EPA is to meet the requirements of environmental laws that it
establish and enforce pollution control standards which are
reasonable, cost effective and provide adequate protection for
the American public.
William C. Galegar
Director
Robert S. Kerr Environmental
Research Laboratory
iii
-------
PREFACE
The sixth annual issue of SELECTED IRRIGATION 'RETURN |
FLOW QUALITY ABSTRACTS has been compiled from approximately
100 sources of material covering calendar year 1976. This
compilation has attempted to include technological-and insti-
tutional articles that would be pertinentxto act ion \progr jams
regarding the control of water quality degradation resulting
from irrigated agriculture. i '-\ j
The state-:of-the-art report, "Characteristics* and Pollu-
tion Problems of Irrigation Return Flowi" prepared by the Utah
State University Foundation contains a bibliography of articles
pertinent to Irrigation Return Flow Quality through 1967. The
first annual issue of SELECTED IRRIGATION RE/TURN 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 1/971, the third annual
issue contained abstracts of articles and reports published
during calendar years 1972 and 197J, and' the^ fourth annual
issue contains abstracts of 1974 publications, and/the fifth
annual issue contains abstracts of 1975 publications. The
sixth annual issue contains 638 abstracts of documents published
during calendar year 1976. The abstracts jiave 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."
IV
-------
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 National Irrigation Re-
turn Flow Research and Development Program. These articles
describe water quality problems resulting from irrigated agri-
culture, potential technological solutions for controlling
return flows, recent research pertinent to return flow investi-
gations, and literature associated with institutional con-
straints 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 and fifth annual issues cover
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.
Key Words: Fertilizers, Irrigated Land, Irrigation Sys-
tems, Irrigation Water, Nitrates, Phosphates, Return Flow,
Salinity, Water Pollution Effects, Water Pollution Sources,
Water Quality Control.
-------
TABLE OF CONTENTS
Foreword iii
Preface iv
Abstract v
Acknowledgments viii
I WATER CYCLE - General (Group 02A) 1
II WATER CYCLE - Precipitation (Group 02B) 5
III WATER CYCLE - Snow, Ice, and Frost (Group 02C) ... 8
IV WATER CYCLE - Evaporation and Transpiration (Group
02D) 9
V WATER CYCLE - Streamflow and Runoff (Group 02E) ... 14
VI WATER CYCLE - Groundwater (Group 02F) 21
VII WATER CYCLE - Water in Soils (Group 02G) 34
VIII WATER CYCLE - Lakes (Group 02H) 81
IX WATER CYCLE - Water and Plants (Group 021) 82
X WATER CYCLE - Erosion and Sedimentation (Group 02J) . 86
XI WATER CYCLE - Chemical Processes (Group 02K) .... 92
XII WATER CYCLE - Estuaries (Group 02L) . 100
XIII WATER SUPPLY AUGMENTATION AND CONSERVATION - Saline
Water Conversion (Group 03A) 101
XIV WATER SUPPLY AUGMENTATION AND CONSERVATION - Water
Yield Improvement (Group 03B) 102
XV WATER SUPPLY AUGMENTATION AND CONSERVATION - Use of
Water of Impaired Quality (Group 03C) 104
XVI WATER SUPPLY AUGMENTATION AND CONSERVATION - Con-
servation in Domestic and Municipal Use (Group 03D) . Ill
XVII WATER SUPPLY AUGMENTATION AND CONSERVATION - Con-
servation in Industrial Use (Group 03E) 112
XVIII WATER SUPPLY AUGMENTATION AND CONSERVATION - Con-
servation in Agriculture (Group 03F) 113
XIX WATER QUANTITY MANAGEMENT AND CONTROL - Control of
Water on the Surface (Group 04A) 164
XX WATER QUANTITY MANAGEMENT AND CONTROL - Groundwater
Management (Group 04B) 169
XXI WATER QUANTITY MANAGEMENT AND CONTROL - Effects on
Water of Man's Nonwater Activities (Group 04C) . . .173
XXII WATER QUANTITY MANAGEMENT AND CONTROL - Watershed
Protection (Group 04D) 174
XXIII WATER QUALITY MANAGEMENT AND PROTECTION - Identifi-
cation of Pollutants (Group 05A) . 177
XXIV WATER QUALITY MANAGEMENT AND PROTECTION - Sources
and Fate of Pollution (Group 05B) 182
VI1
-------
TABLE OF CONTENTS (Cont'd)
XXV WATER QUALITY MANAGEMENT AND PROTECTION - Effects
of Pollution (Group 05C) 205
XXVI WATER QUALITY MANAGEMENT AND PROTECTION - Waste
Treatment Processes (Group 05D) 206
XXVII WATER QUALITY MANAGEMENT AND PROTECTION - Ultimate
Disposal of Wastes (Group 05E) 208
XXVIII WATER QUALITY MANAGEMENT AND PROTECTION - Water
Treatment and Distribution (Group 05F) 209
XXIX WATER QUALITY MANAGEMENT AND PROTECTION - Water
Quality Control (Group 05G) 210
XXX WATER RESOURCES PLANNING - Techniques of Planning
(Group 06A) 221
XXXI WATER RESOURCES PLANNING - Evaluation Process
(Group 06B) 226
XXXII WATER RESOURCES PLANNING - Cost Allocation, Cost
Sharing, Pricing/Repayment (Group 06C) 228
XXXIII WATER RESOURCES PLANNING - Water Demand (Group 06D). 230
XXXIV WATER RESOURCES PLANNING - Water Law and Institu-
tions (Group 06E) 231
XXXV WATER RESOURCES PLANNING - Nonstructural Alterna-
tives (Group 06F) 233
XXXVI RESOURCES DATA - Data Acquisition (Group 07B) . . . 234
XXXVII RESOURCES DATA - Evaluation, Processing and Publi-
cation (Group 07C) 245
XXXVIII ENGINEERING WORKS - Hydraulics (Group 08B) 247
XXXIX ENGINEERING WORKS - Materials (Group 08G) 250
XL AUTHOR INDEX ~. 252
XLI SUBJECT INDEX 269
Vlll
-------
ACKNOWLEGMENTS
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 accom-
plishing the work reported herein.
The efforts of Ms. Teresa Skogg, Ms. Sue Eastman, Ms.
Melanie Lowdermilk, Ms. Helen Malmgren, and Ms. Diane English
in preparing the necessary forms which are forwarded to the
Water Resources Scientific Information Center are sincerely
appreciated, as well as the typing of this final report.
The scope of this literature abstracting effort has been
delineated jointly by the senior author and the 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.
-------
Section I
WATER CYCLE
GENERAL (GROUP 02A)
76:02A-001
HYDROLOGY OF THE NORTH CASCADES REGION, WASHINGTON: I. RUNOFF, PRECIPITATION,
AND STORAGE CHARACTERISTICS,
Rasmussen, L.A., and Tangborn, W.V.
Geological Survey, Tacoma, Washington.
Water Resources Research, Vol. 12, No. 2, p 187-202, April 1976. 10 fig, 7 tab,
6 ref.
Descriptors: *Streamflow forecasting, *Hydrology, Hydrologic data, *Washington,
Equations, Data collections, Evaluation, Methodology, Stream gages. Ice, Snow,
Altitude, Topography, Physical properties.
The time and space distributions of m.easured precipitation and measured runoff and
of spring storage, which is approximately equal to the subsequent summer runoff
of snowmelt and stored groundwater, have been analyzed for the North Cascades
region of Washington. Neither precipitation nor. runoff shows a consistent rela-
tionship with altitude, chiefly because of precipitation-shadowing effects in
this region of high relief. The relationship between mean annual precipitation
and altitude is improved considerably when a topographic mean altitude is used
instead of the actual altitude of the weather station. However, the improvement
is not sufficient to explain a number of discrepancies that still occur. Some
of the scatter in a precipitation-altitude plot appears to be due to a deficient
precipitation catch by high-altitude gages. When the dependence of runoff on
precipitation was examined on an annual, seasonal, and monthly basis, only a few
low-altitude gages correlated well with basin runoff. In several instances,
annual (water year) runoff could be better predicted from winter precipitation
than from annual precipitation.
76:02A-002
HYDROLOGY OF THE NORTH CASCADES REGION, WASHINGTON: II. A PROPOSED HYDROMETEOR-
OLOGICAL STREAMFLOW PREDICTION METHOD,
Tangborn, W.V., and Rasmussen, L.A.
Geological Survey, Tacoma, Washington.
Water Resources Research Vol. 12, No. 2, p 203-216, April 1976. 4 fig, 8 tab,
19 ref.
Descriptors: *Streamflow forecasting, *Model studies, *Hydrology, *Meteorology,
*Washington, Methodology, Hydrologic data. Regression analysis, Hydrologic cycle,
Snow, Ice, Rainfall.
On the basis of a linear relationship between winter (October-April) precipita-
tion and annual runoff from a drainage basin (Rasmussen and Tangborn, 1976) a
physically reasonable model for predicting summer (May-September) streamflow from
drainages in the North Cascades region in Washington was developed. This hydro-
meteorological prediction method relates streamflow for a season beginning on
the day of prediction to the storage (including snow, ice, soil moisture , and
groundwater) on that day. The spring storage is inferred from an input-output
relationship based on the principle of conservation of mass: spring storage
equals winter precipitation to the basin less winter runoff from the basin and
less winter evapotranspiration. The method of prediction is based on data only
from the years previous to the one for which the prediction is made, and the
system is revised each year as data for the previous year become available.
Standard precipitation and runoff measurements in the North Cascades region are
adequate for constructing a predictive hydrologic model. This model can be used
to make streamflow predictions that compare favorably with current multiple
regression methods based on mountain snow surveys. This method has the added
advantages of predicting the space and time distributions of storage and summer
runoff.
-------
76:02A-003
EVALUATION OF A MONTHLY WATER YIELD MODEL,
Haan, C.T.
Kentucky University, Department of Agricultural Engineering, Lexington, Kentucky.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 1,
p 55-60, January-February 1976. 6 fig, 3 tab, 11 ref.
Descriptors: *Model studies, *Watersheds, (Basins), *Runoff, Mathematical models,
Precipitation (Atmospheric), Rainfall, Evapotranspiration, Seepage, Soil water,
Streamflow, Hydrographs, Hydrology, *Water yield.
The results of evaluating the performance of a monthly water yield model on 46
watersheds located in Kentucky, North Carolina, South Carolina, Tennessee, and
Virginia were reported. In general, whenever the watershed being modeled met
the assumptions under which the model was developed, the model performance was
satisfactory. The assumptions included: (1) no runoff due to snow, (2) daily
rainfall evenly distributed over the entire watershed, (3) short delays between
rainfall and runoff, (4) stationary response characteristics between rainfall and
runoff, and (5) record available for parameter estimation is representative of
watershed behavior.
76:02A-004
DISAGGREGATION MODELS IN HYDROLOGY REVISITED,
Mejia, J.M, and Rousselle, ' J.
Ecole Polytechnique de Montreal, Quebec, Canada.
Water Resources Research, Vol. 12, No. 2, p 185-186, April 1976. 5 ref.
Descriptors: *Synthetic hydrology, *Time series analysis, *Statistical models.
Hydrology, Analytical techniques, Correlation analysis. Seasonal, Hydrologic
data, Flow, *Model studies.
The synthesis of hydrologic sequences has been advanced as a useful tool in water
resource systems. Valencia and Schaake developed a methodology for the disaggre-
gation of synthesized yearly flow sequences in such a way that the statistics at
different time resolutions were preserved. Though the data inside a given year
preserve the statistics for all levels of aggregation, they are linked with the
past only through the statistics at the yearly level. To overcome this short-
coming, a modification in the methodology was proposed and tested on 24 years of
hydrologic information for two stations located in the watershed of the North
River. The results supported the theory behind the modified model.
76:02A-005
PARAMETER OPTIMIZATION FOR WATERSHED MODELS,
Johnston, P.R., and Pilgrim, D.H.
New South Wales University, School of Civil Engineering, Kensington, Australia.
Water Resources Research, Vol. 12, No. 3, p 477-486, June 1976. 13 fig, 16 ref.
Descriptors: *Watersheds (Basins), *Mathematical models, *Parametric hydrology,
*0ptimization. Numerical analysis, Performance, Value, Soil moisture. Drainage,
Systems analysis. Model studies.
A detailed search for the optimum values of the parameters <5f the Boughton model
is described. The Simplex and Davidon optimization methods were used. Rapid
initial reductions in the objective function were readily achieved, but the
solutions approached several widely different apparent optima. Alternate use
of different optimization methods and numerical and asgebraic studies enabled
considerable further progress to be made in the search. Much information was
obtained on various aspects of parameter optimization. These include interdepen-
dence and indifference of parameters, the form of the response surface and the
occurrence of discontinuities, the required length of the "warm-up" period for
different types of stores, and the effects of using different types of objective
functions. As typical stores were analyzed and the only basic assumption involved
was that the data contained errors, the findings should apply to most watershed
models.
-------
76:02A-006
MULTISTATION, MULTIYEAR SYNTHESIS OF HYDROLOGIC TIME SERIES BY DISAGGREGATION,
Tao, P.C., and Delleur, J.W.
Purdue University, School of Civil Engineering, Lafayette, Indiana.
Water Resources Research, Vol. 12, No. 6, p 1303-1312, December 1976. 5 fig,
3 tab, 19 ref. OWRT B-036-IND(15).
Descriptors: *Rainfall, *0hio River, *Mississippi River, *Runoff, *Model studies.
Mathematical models, Time series analysis, Rainfall-runoff relationships, Streams,
Graphical analysis, Tributaries, Basins, Correlation analysis. Watersheds (Basins),
Hydrology.
A model was presented which is designed for multivariate (multistation, multi-
year) data syntheses, such as the simulation of several rainfall series over a
region, of tributaries and mainstream runoff series, and of rainfall and concur-
rent runoff series in watersheds. The model was an application of the disaggre-
gation scheme proposed by Valencia and Schaake. If a time series of higher-level
(e.g., annual) events for each station has been generated by some scheme which
preserves the long-term properties, then the disaggregation model can be used
to generate parallel time series of lower-level (e.g., monthly, weekly) events
for each corresponding station. The aggregation of the generated lower-level
sequences can preserve the long-term properties of the original higher-level
series. The seasonal variations, the means, the variances, the autocovariances,
and the cross-covariances, properties of the original lower-level time series,
are also conserved. The lower-level generated series also preserves the corre-
lations between stations. The generation of multivariate normal random numbers
makes use of either the Grout factorization or the principal component analysis,
depending on whether the covariance matrix of the lower-level series is positive
definite or positive semidefinite, respectively. A technique for modeling non-
normal resudual components was discussed. The model was applied to 36 rainfall
runoff, and rainfall-runoff sequences in the lower Ohio and upper Mississippi
River basins located in Indiana, Illinois, Ohio, and Kentucky. The properties
of the generated data series show excellent agreement with those of the histori-
cal observed data series.
76:02A-007
AN ANALYSIS OF THE EFFECTS OF PARAMETER UNCERTAINTY IN DETERMINISTIC HYDROLOGIC
MODELS,
Wood, E.F.
International Institute for Applied Systems Analysis, Laxenburg, Austria.
Water Resources Research,, Vol. 12, No. 5, p 925-932, October 1976. 12 fig,
1 tab, 6 ref.
Descriptors: *Parametric hydrology, *Model studies. Analytical techniques,
*Flood frequency, *Simulation analysis, *Rainfall-runoff relationships.
Stochastic processes, Water resources. Water loss, Systems analysis, Equations,
Risks.
The uncertainty in the output of deterministic models, due to the uncertainty
in the parameters of the model, is analyzed and compared to current procedures
of using average values for the uncertain parameters. The present analysis
considers an analytical rainfall-runoff flood frequency model where the infil-
tration parameter is considered as a stochastic variable. The same conceptual
procedure can be used to analyze fixed but uncertain (unknown) parameters. The
extension to analyzing parameter uncertainty in large simulation models is
indicated, and the importance of such analyses is discussed.
76:02A-008
A DISTRIBUTED CONVERGING OVERLAND FLOW MODEL: II. EFFECT OF INFILTRATION,
Sherman, B., and Singh, V.P.
New Mexico Institute of Mining and Technology, Socorro, New Mexico.
Water Resources Research, Vol. 12, No. 5, p 897-901, October 1976. 4 fig,
15 ref, 1 append.
Descriptors: *Model studies, *Infiltration, *0verland flow, Distribution sys-
tems, Hydrologic systems. Mathematical models, Agricultural watersheds, Runoff,
Rainfall, Rainfall-runoff relationships, Hydrology, Equations.
-------
The overland flow on an infiltrating converging surface was studied. Mathemati-
cal solutions were developed to study the effect of infiltration on nonlinear
overland flow dynamics. To develop mathematical solutions, infiltration and
rainfall were represented by simple time and space, invariant functions. For
complex rainfall and infiltration functions, explicit solutions were not feasible.
-------
Section II
WATER CYCLE
PRECIPITATION (GROUP 02B)
76:02B-001
EVALUATION OF MEAN SQUARE ERROR INVOLVED IN APPROXIMATING THE AREAL AVERAGE OF A
RAINFALL EVENT BY A DISCRETE SUMMATION,
Bras, R.L., and Rodriguez-Iturbe, I.
Puerto Rico University, Department of Civil Engineering, Mayaquez, Puerto Rico.
Water Resources Research, Vol. 12, No. 2, p 181-184, April 1976. 3 fig, 8 ref.
NWS 4-36738.
Descriptors: *Rainfall, *Data processing, *Networks, Mathematics, Mathematical
studies, Analytical techniques, Average, Correlation analysis. Precipitation
(Atmospheric), Hydrology.
Two-dimensional areal processes are commonly evaluated in hydrology through a
discretization in space over the region in which the process is being studied.
Such a discretization involves an error in going from the continuous process to
the discrete one. This error was studied theoretically, and graphs were present-
ed for its evaluation as function of the size of the area, the functional form
of the correlation equation in space,and the level of discretization or size of
the sample. Correlation structures of the Bessel type and of the single and
double exponential kind were considered, and their different implications were
discussed.
76:026-002
FINE-SCALE TIME VARIATIONS OF RAINFALL IN WESTERN OREGON,
Trump, C.L., and Elliott, W.P.
Oregon State University, School of Oceanography, Corvallis, Oregon.
Water Resources Research, Vol. 12, No. 3, p 556,560, June 1976. 3 fig, 3 tab,
11 ref.
Descriptors: *Rainfall, *0regon, *Illinois, *Pacific Ocean, Winter, Linear
programming, Statistics, Storms, Mathematical studies, Precipitation (Atmos-
pheric), Time series analysis, On-site investigations, Variability, Seasonal,
On-site data collections.
One-minute rain rates were measured at three stations on a line running inland
from the coast across a low mountain range during a winter rainy season. The
average of three nondimensional variability statistics were significantly greater
on the coast than inland. Rain rate distributions showed that a greater portion
of the rain fell at higher rates on the coast, and autocorrelation analysis
showed that the rainfall was less persistent on the coast than inland. Oregon
results were compared with similar results concerning Illinois summer convective
rainfall. Even though the Illinois rainfall was distinctly more intense and less
persistent than the Oregon rainfall, the relative variabilities were surprisingly
similar. The logarithm of the total rain falling at rates greater than a given
rate was found to be a linear function of that rate. It was found that the con-
centrations of large airborne sea-salt particles, the cloud-forming nuclei,
peaked at the coastline and dropped off rapidly inland.
76:026-003
RAINFALL GENERATION: A NONSTATIONARY TIME-VARYING MULTIDIMENSIONAL MODEL,
Bras, R.L., and Rodriguez-Iturbe, I.
Puerto Rico University, Department of Civil Engineering, Mayaguez, Puerto Rico.
Water Resources Research, Vol. 12, No. 3, p 450-456, June 1976. 3 fig, 2 tab,
24 ref. NWS Contract 4-36738.
Descriptors: *Rainfall, *Mode-l studies, *Storms, Algorithms, Statistics, Water
resources, Precipitation (Atmospheric), Rainfall intensity, Areal, Hyetographs,
Equations.
-------
Most existing rainfall models do not concentrate on storm exterior characteris-
tics. Very few models attempt to generate exterior and interior rainfall char-
acteristics everywhere in space, and those that do have limiting assumptions of
stationary behavior at all levels of storm activity. Therefore, a nonstationary,
multidimensional model was suggested. The suggested model, capable of simulating
historical storm exteriors and interiors, assumed the validity of G.I. Taylor's
hypothesis turbulence within the storm interior. First-order statistics of
storm interiors as well as the correlation in time and space of the storm inter-
iors were preserved. The model had the advantages of being based on concepts
easy to understand, being multi-dimensional, and being computationally easy to
implement. The research described would be applicable for any kind of rational
description of the rainfall process.
76:02B-004
NETWORK DESIGN FOR THE ESTIMATION OF AREAL MEAN OF RAINFALL EVENTS,
Bras, R.L., Rodriguez-Iturbe, I.
Massachusetts Institute of Technology, Department of Civil Engineering, Cambridge,
Massachusetts.
Water Resources Research, Vol. 12, No. 6, p 1185-1195, December 1976. 11 fig,
6 tab, 17 ref. OWRT C-4118 (No. 9021) (14).
Descriptors: *Design, *Rainfall, *Networks, *Estimating, Optimization, Areal,
Precipitation, Methodology, Sampling, Costs, Stochastic processes, Hydrology,
Equations, Computers, Algorithms, Linear programming, Decision making. Systems
analysis, Mathematical models.
Presented is an efficient network design procedure which is feasible technically
and economically. The procedure combines accuracy (accounting for the process
and instrument uncertainties) and cost considerations in a way flexible enough
to include characteristics and constraints particular to the problem at hand and
to the interested designer. This work recognizes rainfall as a multidimensional
stochastic process. By using the knowledge of such processing and of multivari-
ate estimation theory, the procedure (optimization) for designing an accurate,
least-cost network to obtain the areal mean precipitation of an event over a
fixed area is developed. Data collection is viewed as an estimation problem.
The methodology allows consideration of the following aspects of network design:
(1) spatial uncertainty and correlation of process; (2) errors in measurement
techniques and their correlation; and (3) nonhomogenous sampling costs. Optimal
networks are given in terms of the number of location of stations together with
the resulting cost and mean square error of rainfall estimation.
76:02B-005
RAINFALL NETWORK DESIGN FOR RUNOFF PREDICTION,
Bras, R.L., and Rodriguez-Iturbe, I.
Massachusetts Institute of Technology, Department of Civil Engineering, Cambridge,
Massachusetts.
Water Resources Research, Vol. 12, No. 6, p 1197-1208, December 1976. 5 fig,
3 tab, 17 ref.
Descriptors: *Rainfall, *Stochastic processes, *Networks, *Runoff forecasting,
Equations, Runoff, Kinetics, Basins, Rainfall-runoff relationships. Flood fore-
casting, Discharge (Water), Model studies.
A multivariate, state space stochastic model of rainfall based on a multi-dimen-
sional rainfall generator suggested by Bras and Rodriguez-Iturbe was used,
together with a runoff model, to study the accuracy of discharge prediction as
a function of the rainfall-sampling network. The runoff model used was a spatially
distributed simulation based on a finite difference solution of the kinematic
wave equations. Discharge prediction accuracy at any point in a basin could be
obtained in terms of the mean square error as a function of the number of rain-
sampling devices. The solution was also a function of the physics of the basin
at hand, which was incorporated in the rainfall-runoff model. The mean square
error of discharge estimation was obtained by using linear estimation theory for
dynamic systems. Particularly, the technique used was the Kalman-Buch filter,
which permitted filtering and extrapolation of noisy and incomplete observations.
-------
76:02B-006
COMPUTATION OF SOLAR RADIATION FROM SKY COVER,
Thompson, E.S.
National Weather Service, Office of Hydrology, Silver Spring, Maryland.
Water Resources Research, Vol. 12, No. 5, p 859-865, October 1976. 5 fig,
2 tab, 6 ref, 1 append.
Descriptors: *Cloud cover, *Solar radiation, *Model studies, *Equations,
Mathematical models, Analytical techniques, Data processing, Correlation
analysis, Radiation, Energy transfer. Atmosphere, Meteorology.
A procedure for estimating global solar radiation from sky cover was developed
from the records of 47 stations in the United States, with long periods of
radiation observations during the 10-year period, March 1961 through February
1971. The procedure fits a general parabolic equation of the form Y = B + (1-B)
(1-N to the P power) to the observations, where Y is the observed global solar
radiation divided by clear sky radiation and N is the sky cover. The variables
B (the point at which the parabola crosses the y axis) and P (a variable para-
meter less than 1.0) were selected to minimize the sum of the errors (Y - Y sub
calc squared), where Y sub calc is the calculated value of Y. The equation
Y = B + (1 - B)(1 - N to the 0.61 power) was selected as most representative,
and the B values in this equation that minimize the sum of the errors squared
for the individual stations were shown. The average absolute error of the 5,306
data points is 1.18 MJ/sq m, or 7% of the average observed radiation. Because
of the uncertainties of the observed global solar radiation and observed sky
cover, the procedure should be used with caution, particularly for periods of
less than 1 month.
76:02B-007
A MARKOV CHAIN MODEL OF DAILY RAINFALL,
Haan, C.T., Allen, D.M., and Street, J.O.
Kentucky University, Department of Statistics, Lexington, Kentucky 40506
Water Resources Research, Vol. 12, No. 3, p 443-449, June 1976. 10 tab, 8 ref.
Descriptors: Rainfall, Rainfall disposition, Model studies, Simulation analysis,
Precipitation, Rainfall simulators.
The design of many water resources projects requires knowledge of possible long-
term rainfall patterns. A stochastic model based on a first-order Markov chain
was developed to simulate daily rainfall at a point. The model uses historical
rainfall data to estimate the Markov transitional probabilities. A separate
matrix is estimated for each month of the year. In this research, 7 times 7
transitional probability matrices were used. The model is capable of simulating
a daily rainfall record of any length, based on the estimated transitional prob-
abilities and frequency distributions of rainfall amounts. The simulated data
have statistical properties similar to those of historical data.
76:02B-008
UNIFORMITY AMONG WEATHER MODIFICATION LAWS,
Davis, R.J.
Arizona University, Department of Law, Tucson, Arizona
Journal of the Irrigation and Drainage Division, Volume 102, No. IR3, p 285-294,
September 1976. 1 tab, 11 ref.
Descriptors: Weather modification, Cloud seeding, Precipitation, Rainfall.
Advocates of weather modification would do well to consider the advantages of uni-
formity and of diversity in laws relating to cloud seeding. They should support
state legislation that promotes uniformity where it is useful and retains diversity
where it is rational to do so. When additional federal legislation is considered,
the weather modification community should press for provisions that permit reten-
tion of diversity among states where it is advantageous. Neither Procrustes nor
Balkanization should prevail.
-------
Section III
WATER CYCLE
SNOW, ICE, AND FROST (GROUP 02C)
76-.02C-001
AN ANALYSIS OF WATER FLOW IN DRY SNOW,
Colbeck, S.C.
Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire.
Water Resources Research, Vol. 12, No. 3, p 523-527, June 1976. 3 fig, 1 tab,
12 ref. Army 4A161102B52E.
Descriptors: *Water supply, *Snow, Water, Advection, Water measurement. Runoff,
Wetting, Temperature, Adsorption, Flow rates, Thermodynamic behavior. Flow,
Grain size, Time lag, Discharge (Water), Equations.
Equations describing water movement in a dry snow cover were derived, and exam-
ples of flow through ripe, refrozen, and fresh snows were given. As the leading
edge of a wave of liquid water advanced into subfreezing snow, the liquid water
was the principal source of the thermal energy needed to raise the snow to its
melting temperature, because advection of water is generally faster than heat
conduction. There are three requirements which have to be met before the wetting
front can propagate past any level. First, a volume of water per unit volume of
snow has to be frozen onto the snow grains in order to supply enough latent heat
to raise the snow to O.C. Second, a volume of water per unit volume of snow has
to be supplied to fill the residual water requirement, retained as an adsorbed
film, and the water held immobile in the menisci between the snow grains. Third,
any additional water supplied is mobile, and in principle the wetting front prop-
agates downward at a rate determined by the rate at which water can be supplied
to raise the liquid saturation to the level which corresponds to the value of
water flux just above the wetting front. These requirements delay and reduce
runoff following rain on dry snow.
-------
'Section IV
WATER CYCLE
EVAPORATION AND TRANSPIRATION (GROUP 02D)
76:020-001
RELATIVE IMPORTANCE OF SOIL RESISTANCE AND PLANT RESISTANCE IN ROOT WATER
ABSORPTION,
Reicosky, D.C., and Ritchie, J.T.
Agricultural Research Service, Florence, South Carolina, Southern Region.
Soil Science Society of America Journal, Vol. 40, No. 2, p 293-297, March-April
1976. 3 fig,. 1 tab, 32 ref.
Descriptors: *Soil-water-plant relationships, *Moisture uptake, *Soil water,
*Transpiration, Water loss. Leaves, Corn, Sorghum, Nutrients, Root zone,
Absorption, Sands, Soil types, Clays, Hydraulic conductivity.
The relative importance of soil and plant resistances and their influence on
leaf water potential and transpiration over a range of measured hydraulic con-
ductivities and matric potentials commonly encountered in Varina sandy loam and
Houston Black Clay was evaluated. Experiments were conducted on corn grown in
a greenhouse and sorghum grown in a field. Soil water potentials, leaf water
potentials, and transpiration rates were determined to evaluate the magnitude of
the combined soil and plant resistances to water flow in the plant system.
Results show that when root density was not unusually low, plant resistance to
water transport was much larger than soil resistance until a higher threshold
soil hydraulic conductivity was reached. These findings emphasize the need to
consider plant resistance in moisture uptake calculations when using equations
that evaluate water potential gradients along the water flow path.
76:020-002
EVAPOTRANSPIRATION MODEL TESTED FOR SOYBEAN AND SORGHUM,
Kanemasu, E.T., Stone, L.R., and Powers, W.L.
Kansas State University, Department of Agronomy, Manhattan, Kansas.
Agronomy Journal, Vol. 68, No. 4, p 569-572, July-August 1976. 3 fig, 3 tab,
13 ref. OWRT A-056-KAN(3).
Descriptors: *Evapotranspiration, *Sorghum, *Soybeans, *Model studies. Evapor-
ation, Transpiration, Advection, Stomata, Lysiraeters, Temperature, Soil moisture,
Soil water movement. Solar radiation.
Daily evapotranspiration estimated using a new model applied to sorghum and soy-
beans was within 2 mm of estimates by lysimetric observation. The model employs
daily inputs of temperature, solar radiation and leaf area index; outputs include
transpiration and evaporation. The model has potential in scheduling irrigation
on a routine basis. Seasonal evaporation accounted for 15 to 20% of the evapo-
transpiration which was about 10% greater from soybeans than from sorghum.
Nightime evapotranspiration losses (lysimetric) from soybeans were also 1.8
times greater, indicating lower stomatal resistance. Leaf area indices indica-
ted a greater surface iresistance for sorghum.
76:020-003
AN EVAPORATION EQUATION FOR AN OPEN BODY OF WATER EXPOSED TO THE ATMOSPHERE,
Goodling, J.S., Sill, B.L., and McCabe, W.J.
Auburn University, Department of Mechanical Engineering, Alabama.
Water Resources Bulletin, Vol. 12, No. 4, p 843-853, August 1976. 3 fig,
10 ref.
Descriptors: *Evaporation, *Forced drying, *Wind velocity, Temperature, Air,
Heat flow, Winds, Mass transfer-, Equations, Air temperature, Numerical analy-
sis. Mathematical studies.
Evaporation was identified as having two additive components: natural evapo-
ration in the absence of wind, and forced evaporation in the presence of wind.
-------
An evaporation equation was obtained for an open body of water exposed at the
atmosphere by conversion of standard, horizontal flat plate heat transfer rela-
tionships to a mass transfer or evaporation equation, based on an average air
temperature of 68F. A comparison of numerical values predicted by this equation
was made with evaporation equations deduced from field measurements, and the
agreement was favorable. The major differences between this equation and those
previously developed were; (1) This equation was derived strictly from standard
heat transfer expressions, and (2) A dependency of average fetch and air temp-
erature (through transport properties) was shown. This approach established
the correct dependencies of the field parameters so that future experimental
measurements would have a sound theoretical basis.
76:02D-004
MODEL FOR PREDICTING EVAPOTRANSPIRATION FROM NATIVE RANGELANDS IN THE NORTHERN
GREAT PLAINS,
Hanson, C.L.
Agricultural Research Service, Northwest Watershed Research Center, Boise, Idaho.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 471-481, May-June 1976. 5 fig, 4 tab, 42 ref.
Descriptors: *Evapotranspiration, *Range grasses, *Vegetation, *Model studies,
*Great Plains, Water, Energy budget, Soil water, Ranges, Forecasting, Estimating,
Mathematical models, On-site data collections.
A study was made to develop a model for estimating evapotranspiration from North-
ern Great Plains native rangeland, based on potential evapotranspiration, avail-
able soil water,- leaf area, and direct evaporation from the soil and intercepted
water from plants. To calibrate and test the model, data from Gillette, Wyoming,
Cottonwood, South Dakota, and Sidney, Montana, were collected and evaluated. An
optimization routine was employed to obtain the parameter values of the model.
To estimate potential evapotranspiration, an approximate energy balance method
and the- United States Weather Bureau Class A pan evaporation were used because
the data required by them were available or easily computed. The approximate
energy balance method required daily solar radiation and mean daily air tempera-
ture. Based on model verification, the energy balance equation and the pan evap-
oration equation could be used to predict daily as well as mean 5-, 7-, and 10-
day potential evapotranspiration. Model evaluation also indicated that it was
better to use the approximate energy balance method than the Class A pan method
for potential evapotranspiration. The model predicted daily as well as mean
evapotranspiration better in loam soil areas than in fine clay soil areas.
76:020-005
CALCULATION OF EVAPORATION RATES DURING THE TRANSITION FROM ENERGY-LIMITING TO
SOIL-LIMITING PHASES USING ALBEDO DATA,
Jackson, R.D., Idso, S.B., and Reginato, R.J.
Agricultural Research Service, Water Conservation Lab, Phoenix, Arizona.
Water Resources Research, Vol. 12, No. 1, p 23-26, February 1976. 5 fig, 20 ref.
Descriptors: *Evaporation, *Energy transfer, *Soils, Albedo, Soil surfaces,
Potential flow, Lysimeters.
A method was presented that utilizes albedo measurements to partition the fraction
of the soil surface area exhibiting energy-limiting (potential) evaporation and
the fraction exhibiting soil-limiting evaporation to calculate actual evaporation
rates during the transition phase (energy limiting to soil limiting). Since
albedo is proportional to the surface water content, the change in albedo from
day to day was indicative of the fraction of the soil surface that was dry and
evaporating at the soil-limiting rate. By denoting the partitioning factor as
beta and by using a square root of time relation with a coefficient C for the
soil-limiting phase the evaporation rate EC for a day n after the soil was wet
was expressed by a formula where Ep was the energy-limiting rate. The Priestly-
Taylor formula was used to calculate Ep. Calculated evaporation rates were com-
pared with lysimetrically determined rates. It was concluded that this method
is reliable for calculating evaporation rates during the transition phase of soil
drying.
10
-------
76:020-006
RELATION OF THE CONSUMPTIVE USE COEFFICIENT TO THE DESCRIPTION OF VEGETATION,
Culler, R.C., Hanson, R.L., and Jones, J.E.
Geological Survey, Tucson, Arizona.
Water Resources Research, Vol. 12, No. 1, p 40-46, February 1976. 6 fig, 1 tab,
21 ref.
Descriptors: *Evapotranspiration, *Hydrologic budget, *Arid climates, *Arizona,
Flood plains, Correlation analysis, *Vegetation, *Consumptive use, Transpiration,
Analytical techniques, Aerial photography. Remote sensing. Equations.
Evapotranspiration from three reaches of the Gila River flood plain in Arizona
was measured by the water budget during 1963-1971. Initially, the vegetation
consisted of salt cedar and mesquite with densities of canopy ranging from 10 to
100%. The phreatophytes were removed in stages during 1967-1971. Perennial
grass seed was applied but did not becore established, and the postclearing
vegetation was primarily annuals. Comparison of the evapotranspiration data from
various reaches and comparison of data from before and after clearing required
the application of an empirical equation. A consumptive use coefficient related
to the description of vegetation was applied to an existing potential evapotrans-
piration equation based on macroclimatic observations. Initially, the vegetation
description consisted of plant identification and canopy dimensions obtained by
use of black and white aerial photography and ground measurements. In 1967,
remote sensing in the form of color infrared aerial photography became available
and densitometric interpretation was used to develop a spectral signature as the
vegetation descriptor.
76:020-007
RESISTANCE-ENERGY BALANCE METHOD FOR PREDICTING EVAPOTRANSPIRATION: DETERMINA-
TION OF BOUNDARY LAYER RESISTANCE AND EVALUATION OF ERROR EFFECTS,
Verma, S.B., Rosenberg, N.J., Blad, B.L., and Baradas, M.W.
Kansas Water Resources Research Institute, Manhattan, Kansas.
Contribution No. 172, December 1975, p.I-1 thru 1-29.
Descriptors: *Evapotranspiration, *Model studies, Measurement, *Sorghum, *Millet,
*Advection, Lysimeters, Energy balance, Micrometerology, Microclimates, Heat
transfer, Latent heat, Crop response.
A resistance model of evapotranspiration (ET) requiring measurement of boundary
layer resistance, cjrop and air temperature, net radiation and soil heat flux was
tested over sorghum and millet grown at Mead and Mitchell, Nebraska. Boundary
layer resistance was estimated from friction velocity measurements used in a
stability-corrected aerodynamic method. Friction velocity was computed by means
of the Deacon-Swinbank approach. Evapotranspiration rates estimated by the
resistance model compared well with results of lysimetric and energy balance
measurements, on both a short-period and a daily basis. An error analysis was
made to evaluate the relative influence of errors in measurement of the constitu-
ent input parameters. This analysis, in conjunction with field measurement,
indicates that the resistance model evapotranspiration estimates are quite sensi-
tive to errors in crop temperature measurement, especially in non-advective
conditions, but are less strongly affected by errors in the. estimation of bound-
ary layer resistance. Boundary layer resistance for the sorghum and millet
crops at varying stages of growth are presented as functions of windspeed.
76:020-008
AN EVALUATION OF A RESISTANCE FORM OF THE ENERGY BALANCE TO ESTIMATE EVAPOTRANS-
PIRATION,
Heilman, J.L., and Kanemasu, E.T.
Kansas Water Resources Research Institute, Manhattan, Kansas.
Contribution No. 172, December 1975, p II-l thru 11-22.
Descriptors: *Evapotranspiration, *Model studies, Boundary layers, Heat resis-
tance, Latent heat, Heat transfer, Lysimeters, Sorghum, Soybeans, Crop response.
An evapotranspiration model that uses the diffusion resistance to heat transport
(rH) in the turbulent boundary layer was evaluated for soybean (Glycine max (L.)
cv. Williams) and sorghum (Sorghum bicolor (L.) cv. Pioneer 846). Model estimates
11
-------
of latent heat flux (LE) were within 4% and 15% of lysimetric measurements for
soybeans and sorghum, respectively. When using resistance to momentum (rD),
estimates of LE for soybean were 25% greater, but for sorghum only 10% greater
than when using resistance to heat transport (rH).
76:020-009
ESTIMATING GROUNDWATER EVAPOTRANSPIRATION FROM STREAMFLOW RECORDS,
Daniel, J.F.
Geological Survey, Doraville, Georgia.
Water Resources Research, Vol. 12, No. 3, p 360-364, June 1976. 5 fig, 10 ref.
Descriptors: *Evapotranspiration, *Groundwater, *Estimating, *Model studies,
*Streamflow, Flow rates. Aquifer characteristics, Transmissivity, Surface-ground-
water relationships, Hydrologic data, *Alabama.
An analytical solution for the evapotranspiration rate from the aquifer system
of a stream basin was applied to a selected basin despite large-scale violations
of assumptions for the derivation. Rates computed represent losses from the
groundwater bodies and do not include losses from soil moisture. The computed
rate for the 23.00 sq km basin, Indian Creek near Troy, Alabama, during April
and May 1963 was 0.037 cu m/sec, or about 0.5 cm/month. Such results should be
reliable enough to use in rainfall-runoff models and, in the absence of more
detailed data, in areal groundwater models.
76:020-010
EVAPOTRANSPIRATION FROM A SHORT-GRASS PRAIRIE SUBJECTED TO WATER AND NITROGEN
TREATMENTS,
Lauenroth, W.K., and Sims, P.L.
Colorado State University, Natural Resource Ecology Lab, Fort Collins, Colorado.
Water Resources Research, Vol. 12, No. 3, p 437-442, June 1976. 8 fig, 1 tab,
18 ref. U.S. International Biological Program Grassland Biome. NSF GB-7824,
GB-13096.
Descriptors: *Evapotranspiration, *Prairie soils, *Grasses, *Colorado, *Great
Plains, Water, Nitrogen, Water balance, Soil-water-plant relationships, Energy
budget, On-site inbestigations, Soil treatment.
Evapotranspiration was estimated by the water balance method for three water and
nitrogen treatments and a control in a shortgrass prairie in northeastern
Colorado in 1971, 1972, and 1973. Nitrogen was applied at a rate of 150 kg/ha
to maintain soil mineral nitrogen levels greater than or equal to 50 kg/ha above
control levels with and without supplemental water. The water treatment main-
tained soil water potential greater than -0.8 bar during the growing season and
was applied with and without nitrogen. Evapotranspiration for the control and
unwatered nitrogen treatments was not different and ranged from 118 to 226 mm
over the 3 years. The 3-year averages of evapotranspiration for the water plus
nitrogen treatments were 505 and 578 mm, respectively- Evapotranspiration for
the water plus nitrogen treatment agreed with potential evapotranspiration
predicted by Penman's model.
76:020-011
A SIMPLE METHOD FOR DETERMINING THE EVAPORATION FROM SHALLOW LAKES AND PONDS,
Stewart, R.B., and Rouse, W.R.
Atmospheric Environment Service, Downsview, Ontario, Canada.
Water Resources Research , Vol. 12, No. 4, p 623-628, August 1976. 9 fig, 13 ref.
Descriptors: *Evaporation, *Lakes, *Energy budget, *Radiation, Ponds, Equilibrium,
Solar radiation, Air temperature. Models, Equations, On-site investigations,
Mathematical studies.
The summertime evaporation from a shallow lake in the Hudson Bay lowlands was
evaluated by the energy budget (Bowen ratio) and equilibrium model approaches.
Energy budget calculations revealed that, on the average, 55% of the daily net
radiation was utilized in the evaporative process over the lake. Half-hourly
and daily values of evaporation were approximated closely by the Priestly and
Taylor (1972) model, where the ratio of actual-to-equilibrium evaporation
12
-------
equalled 1:26. A simple model, expressed in terms of incoming solar radiation
and screen height air temperature, was developed from the comparison of actual-
to-equilibrium evaporation. Tests of the model at a different location indica-
ted that the actual evaporation could be determined within 10% over periods of
two weeks.
76:020-012
SENSITIVITY AND MODEL VARIANCE ANALYSIS APPLIED TO SOME EVAPORATION AND EVAPO-
TRANSPIRATION MODELS,
Coleman, G., and DeCoursey, D.G.
Agricultural Research Service, Chickasha, Oklahoma.
Water Resources Research, Vol. 12, No. 5, p 873-879, October 1976. 2 fig,
2 tab, 16 ref.
Descriptors: *Analytical techniques, *Mathematical models, Forecasting, *Evap-
oration, *Evapotranspiration, Model studies.
Variable sensitivity and error variance of six evaporation and evapotranspira-
tion models were calculated. Their sensitivity values were computed by approx-
imating the partial derivatives by finite differences. To compare the models,
relative sensitivity was computed as the percent change in evaporation per
unit change in the input variable. A second relative sensitivity was calculated
to compare the relative importance of the different input variables. Error
variance was analyzed to find the variance of error due to instrument inaccura'-
cies using instrument variance estimated from the manufacturer's statements.
Although no tests were conducted to determine the bias or prediction accuracy
of the model, a technique was proposed to show how the instrument error variance
could be added to the prediction error variance to determine the overall system
variance. In model development the best model will be one whose sum of these
two variances is a minimum if there is no prediction bias.
76:020-013
THE APPLICABILITY OF PLANETARY BOUNDARY LAYER THEORY TO CALCULATE REGIONAL
EVAPOTRANSPIRATION,
Brutsaert, W., and Mawdsley, J.A.
Cornell University, College of Engineering, Ithaca, New York.
Water Resources Research, Vol. 12, No. 5, p 853-858, October 1976. 4 fig,
40 ref. NSF GA-42569.
Descriptors: *Boundary layers, *Evapotranspiration, *Model studies,
Evaporation, Transpiration, Water supply, Theoretical analysis. Mass transfer,
Atmosphere, Atmospheric physics, Drought, Flood forecasting.
A formulation was obtained for the calculation of evapotranspiration from a
region even when the water supply to the surface is limited. The theoretical
model was based on general similarity principles for a steady, uniform boundary
layer under any conditions of atmospheric stability- The resulting mass trans-
fer formulae have the advantage that the necessary data (rawinsonde) are often
routinely published or otherwise easily available. In contrast, most methods
used for the determination of evapotranspiration require either a special
experimental setup for rarely available data or are purely empirical and with-
out a firm physical base. The proposed method could be applied in hydrologic
simulation for drought studies and for the determination of antecedent
moisture conditions in flood prediction.
13
-------
Section V
WATER CYCLE
STREAMFLOW AND RUNOFF (GROUP 02E)
76:02E-001
DISSOLVED NUTRIENT LOSSES IN STORM RUNOFF FROM FIVE SOUTHERN PINE WATERSHEDS,
Schreiber, J.D., Duffy, P.O., and McClurkin, D.C.
United States Department of Agriculture, Department of Soil Science, Oxford,
Mississippi.
Journal of Environmental Quality, Vol. 5, No. 2, p 201-205, April-June 1976.
2 fig, 6 tab, 21 ref.
Descriptors: *Runoff, Erosion, Storm runoff. Watersheds (basins), Nutrients,
Sampling, Mississippi, Water quality, Precipitation, Nitrogen, Phosphorus,
Cations.
Storm runoff from five reforested eroded watersheds in northern Mississippi was
analyzed during the 1973 water year to determine the concentrations of soluble
N03-N, NH4-N, PO4-P, Ca, Mg, and K. Storm runoff was measured with 0.91-m
H-flumes and samples collected with Coshocton wheel sampler. Analysis of preci-
pitation which totaled 189 cm for the year, 40% above average, revealed that
inputs of NO3-N, NH4-N, P04-P, Ca, Mg, and K for the year were 3.12, 5.73, 0.07,
7.72, 3.03, and 4.98 kg/ha respectively. Soluble nutrient losses in the storm
runoff on a unit area basis were similar for the five watersheds. Average losses
in storm runoff of soluble NO3-N, NH4-N, P04-P, Ca, Mg, and K for the year were
0.32, 3.35, 0.04, 6.21, 3.05, and 3.31 kg/ha respectively. As the annual storm
runoff among the watersheds increased, the N03-N losses also increased linearly.
Data for individual storms indicated that a critical storm runoff value must be
exceeded before the watersheds would exhibit a net loss of each nutrient.
76:02E-002
LOSS OF 2,4-D IN RUNOFF FROM PLOTS RECEIVING SIMULATED RAINFALL AND FROM A SMALL
AGRICULTURAL WATERSHED,
White, A.W. Jr., Asmussen, L.E., Hauser, E.W., and Turnbull, J.W.
United States Department of Agriculture, Agricultural Research Service, Soil
Science and Chemistry, Byron, Georgia.
Journal of Environmental Quality Vol. 5, No. 4, p 487-490, October-December
1976. 2 fig, 2 tab, 24 ref.
Descriptors: *2,4-D, *Runoff, Agricultural watersheds. Simulated rainfall,
Surface runoff. Herbicides, Soil profiles, Water pollution, Soils, Leaching.
Movement of 2,4-D was not significant in either surface or subsurface runoff
from a small agricultural watershed on a sandy Coastal Plain soil. Surface
runoff levels were highest for the first runoff event after herbicide application
(0.56 kg/ha) each year, and initial concentrations were related to the time
lapse between herbicide application and the date of the first runoff event.
Maximum concentrations were 8.1, 6.2, and 2.5 micro g/liter in 1970, 1971, and
1972, respectively. The corresponding time lapse for the same years was 20, 27,
and 34 days. Persistence studies showed that the 2,4-D concentration in the
surface 0.5 cm of soil decreased 95%, from 4.7 to 0.23 ppm in only 7 days, and
after 34 days the soil concentration was only 0.01 ppm. Although subsurface
flow was three times greater than surface runoff during the 3-year period,
2,4-D movement in subsurface water was negligible. Concentrations were usually
zero or < 1 micro g/liter. Soil sampled to a 90-cm depth showed no 2,4-D
accumulation or build-up in the soil profile. Simulated rains (8.25 cm in 30
min) applied to subplots on the watershed showed that there is a potential for
greater 2,4-D losses in surface runoff when it rains soon after herbicide
application. When rains were applied 1,8, and 35 days after herbicede applica-
tion, the average 2,4-D concentrations in runoff were 25.2, 5.8, and 0.7 micro
g/liter, respectively.
14
-------
76:02E-003
IDENTIFICATION OP LINEAR SYSTEMS RESPONSE BY PARAMETRIC PROGRAMMING,
Neuman, S.P., and Marsily, G.D.
Arizona University, Department of Hydrology and Water Resources, Tucson, Arizona.
Water Resources Research, Vol. 12, No. 2, p 253-262, April 1976. 18 fig, 23 ref.
Descriptors: *Input-output analysis, *Hydrograph analysis, *Runoff forecasting,
Analytical techniques, *Linear programming, Hydrologic systems, Hydrology,
Decision making, Hydrologic data, Precipitation (Atmospheric).
The impulse response function of a linear hydrologic system is extremely sensi-
tive to minor errors in the input-output data. Low-amplitude random errors can
cause severe oscillations in the response function. Objective methods are not
available for filtering the input-output data to obtain physically realizable
solutions. The ultimate goal of response function identification is to deter-
mine a solution which optimizes the predictive capabilities of the linear model.
An important criterion of optimality is that the shape of the response function
be physically plausible. Use of parametric linear programming was proposed to
achieve this objective. The problem was formulated as a multicriterion decision
process under uncertainty. Parametric programming served as a means of genera-
ting a continuous set of alternative solutions to the identification problem
together with a bicriterion function representing these alternatives. The shape
of the bicriterion curve was then used as a guide by the hydrologist in select-
ing a particular solution when he is relying on his own value judgment.
76:02E-004
ISOTOPIC HYDROLOGY IN THE AMAZONIA II. RELATIVE DISCHARGES OF THE NEGRO AND
SOLIMOES RIVERS THROUGH 0-18 CONCENTRATIONS,
Matsui, E., Salati, F. , Friedman, I., and Brinkman, W.L.F.
Centro de Energia Nuclear na Agriculture, Sao Paulo, Brazil; and Geological
Survey, Denver, Colorado.
Water Resources Research, Vol. 12, No. 4, p 781-785, August 1976. 4 fig, 2 tab,
15 ref.
Descriptors: *streamflow, *Flow rates, *0xygen isotopes, *Hydrology, *South
America, *Precipitation (Atmospheric), Runoff, Sampling, Water analysis, Ion
transport, Mixing, Tributaries.
Measurements of 0-18,were made on samples of water collected during a 2-year
period on the Amazon below the confluence of the Negro and Solimoes rivers.
The measurements show that the Amazon is not completely mixed 120 km below the
confluence. Estimates of relative flows were based on the 0-18 concentrations
and show that the relative contribution of the Negro varied from 19% in Febru-
ary 1973 to 68% in July 1973.
76:02E-005
MODELING MONTHLY HYDROLOGIC PERSISTENCE,
Young, G.K., and Jettmar, R.U.
Catholic University of America, Department of Civil Engineering, Washington,
D.C.
Water Resources Research, Vol. 12, No. 5, p 829-835, October 1976. 5 fig,
3 tab, 7 ref, 1 append. OWRT C-3029(No. 3730) (2) .
Descriptors: *Streamflow, *Persistence, *Model studies, Mathematical models,
Runoff, Monthly, Analytical techniques, Statistical analysis, Correlation
analysis, Streamflow forecasting, Rivers, Hydrology-
This paper reported an empirical study of the autocorrelations and Hurst para-
meter properties for monthly Streamflow for a set of U.S. Geological Survey
gaging stations in the eastern United States. The analysis was motivated by a
desire to develop operational criteria to select persistence measures and gener-
ating models. The work was part of a larger effort to evaluate the trade-offs
between complex and simple data generators. Markov generators are simple in
comparison to the more complex self-similar methods. Monthly Streamflow data
were found to have Hurst statistics similar to annual data. Least squares was
presented as a possible method to estimate persistence parameters and to select
15
-------
models. Empiric autocorrelations were treated as data in a fit of theoretic
covariance functions by minimum squared error. The Hurst and least squares
estimators are nearly the same. The lag 1 correlation is much smaller than
least squares estimators. A step-by-step procedure was suggested for implemen-
tation of least squares persistence analysis.
76:02E-006
A DISTRIBUTED CONVERGING OVERLAND FLOW MODEL III. APPLICATION TO NATURAL
WATERSHEDS,
Singh, V.P.
New Mexico Institute of Mining and Technology, Socorro, New Mexico.
Water Resources Research, Vol. 12, No. 5, p 902-908, October 1976. 8 fig,
1 tab, 13 ref.
Descriptors: *Overland flow, *Model studies, *Watersheds (Basins), Runoff,
Agricultural watersheds. Parametric hydrology, Hydrology, Rainfall-runoff rela-
tionships, Mathematical studies. Equations, Flow.
The proposed distributed converging overland flow model was utilized to predict
surface runoff from three natural agricultural watersheds. The Lax-Wendroff
scheme was used to obtain numerical solutions. For determination of the kine-
matic wave friction relationship parameter, a simple relation between the para-
meter and topographic slope was hypothesized. The simple relation contains two
constants which are optimized for each watershed by the Rosenbrock-Palmer opti-
mization algorithm. The model results were in good agreement with runoff obser-
vations from these watersheds. It was shown that if the model structure is
sound, it will suffice to optimize model parameters on hydrograph peak only,
even for prediction of the entire hydrograph. The model results suggested that
a distributed approach to kinematic wave modeling of watershed surface runoff
is potentially promising and warrants further investigation.
76:02E-007
MORPHOMETRY AND FLOODS IN SMALL DRAINAGE BASINS SUBJECT TO DIVERSE HYDROGEO-
MORPHIC CONTROLS,
Patton, P.C., and Baker, V.R.
Texas University, Department of Geological Sciences, Austin, Texas.
Water Resources Research, Vol. 12, No. 5, p 941-952, October 1976. 7 fig,
12 tab, 46 ref. NWS A-35460, NASA NAS 9-13312.
Descriptors: *Texas, *Watersheds (Basins), *Geomorphology, *Floods, Drainage
area, Geologic control, Drainage density, Drainage patterns (Geologic), Drain-
age systems, Hydrology, Flood peak.
Morphometric parameters, such as drainage density, stream magnitude, and relief
ratio, are practical measures of flood potential in small (less than 100 sq mi)
drainage basins. Stereoscopic interpretation of low-altitude aerial photographs
provides the most accurate maps of basins for generating these parameters.
Field surveys of a high-density limestone basin in central Texas showed that
1:24,000 scale topographic maps accurately portray the.efficient stream channel
system but fail to reveal numerous small gullies that may form portions of hill-
slope hydrologic systems. Flood potential in drainage basins can be defined by
a regional index computed as the standard deviations of the logarithms of the
annual maximum streamflows. High potential basins tend toward greater relief,
greater drainage density,and, thus, greater ruggedness numbers than low-flash
flood potential watersheds. For a given number of first-order channels (basin
magnitude), flash flood regions have greater ruggedness numbers, indicating
higher drainage densities combined with steep hillslopes and stream channel
gradients. Transient controls on flood response, such as differences between
local rainstorm intensities, appear to be the major influences on hydrographs
in areas of moderate dissection and relief. Morphometric parameters for low-
potential flash flood regions (Indiana and the Appalachian Plateau) are better
estimators of frequent low-magnitude runoff events (mean annual flood), while
the same parameters correlate better with the maximum flood of record in high-
flood potential regions (central Texas, southern California, and north central
Utah).
16
-------
76:02E-008
WATER TEMPERATURE FORECASTING AND ESTIMATION USING FOURIER SERIES AND COMMUNICA-
TION THEORY TECHNIQUES,
Long, L.L.
Tennessee Technological University, Department of Mathematics, Cookeville,
Tennessee.
Water Resources Research, Vol. 12, No. 5, p 881-887, October 1976. 11 fig,
2 tab, 9 ref.
Descriptors: *Water temperature, *Analytical techniques, *Regression analysis,
*Fourier analysis. Model studies. Mathematical models, Temperature, Rivers,
Forecasting, Time series analysis. Statistics, Statistical methods. Mathematics.
Fourier series and statistical communication theory techniques were utilized in
the estimation of river water temperature increases caused by external thermal
inputs. An example estimate, assuming a constant thermal input, was demonstra-
ted. A regression fit of the Fourier series approximation of temperature was
then used to forecast daily average water temperatures. Also, a 60-day pre-
diction of daily average water temperature was made, with the aid of the
Fourier regression fit, by using significant Fourier components.
76:02E-009
A DISTRIBUTED CONVERGING OVERLAND FLOW MODEL I. MATHEMATICAL SOLUTIONS,
Sherman, B., and Singh, V.P.
New Mexico Institute of Mining and Technology, Socorro, New Mexico.
Water Resources Research, Vol. 12, No. 5, p 889-896, October 1976. 10 fig,
16 ref, 3 append.
Descriptors: *Model studies, *Mathematical models, *0verland flow, *Distribu-
tion systems, Hydrologic systems, Infiltration, Agricultural watersheds,
Watersheds (Basins), Hydrology.
In models for overland flow based on kinematic wave theory, the friction
parameter is assumed to be constant. This paper reported a study of a con-
verging geometry which allows continuous spatial variability in the parameter.
Parameter variability results in a completely distributed approach, reduces the
need to use a complex network model to sumulate watershed surface runoff, and
saves much computational time and effort. This paper was the first in a series
for a converging geometry with no infiltration and with temporally constant
lateral inflow. Part 2 discussed the effect of infiltration on the runoff pro-
cess, and part 3 discussed application of the proposed model to natural"agri-
cultural watersheds.
76:02E-010
THE RELATIONSHIP BETWEEN LIGHT AND PHOTOSYNTHETIC RATE IN A RIVER COMMUNITY AND
IMPLICATIONS FOR WATER QUALITY MODELING,
Hornberger, G.M., Kelly, M.G., and Eller, R.M.
Virginia University, Department of Environmental Sciences, Charlottesville,
Virginia 22903
Water Resources Research, Vol. 12, No. 4, p 723-730, August 1976. 7 fig, 1 tab,
31 ref.
Descriptors: Photosynthesis, Aquatic environment. Aquatic habitats, Nutrients,
Inhibition, Modeling, Model studies, Water quality.
Saturation of photosynthesis at naturally occurring high light intensities has
widely been reported for aquatic communities. Contrary to this, using free water
measurement methods, we found a relationship between light intensity and photo-
synthesis in a small river that was unmistakably linear dn cloudless days and on
days when points corresponding to times of highly variable radiation were dis-
carded. The linear relationship obtained through the year. Simulations of
nutrient-limited growth in light-dark bottles show that nutrient depletion effects
can explain the cases of light saturation and inhibition previously reported in
the literature. If light saturation and inhibition of photosynthesis are due
even in part to artificially induced nutrient limitation, then the inclusion of
nonlinear light terms in water quality models is inappropriate.
17
-------
76:02E-011
COMPATIBLE SEDIMENT CONTROL PRACTICES AND TILLAGE SYSTEMS,
Tompkins, F.D., Shelton, C.H., and Temple, J.E.
Tennessee University, Department of Agricultural Engineering, Knoxville, Tennessee.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 16 p, 4 fig, 3 tab, 5 ref.
Descriptors: Sediments, Sediment control, Flow resistance. Soybeans, Runoff,
Watersheds, Return flow.
The results of this study indicate that pattern efficiency for a graded system was
about the same as that for the conventional cropping pattern previously used. The
angle at which the rows intersect the headland affects the time required for turn-
ing. Time required for turning increases as the intersection angle increasingly
deviates from 90 degrees. Soybean yields obtained after land grading were some-
what higher than the station average. This suggests that, for the study area,
soil disturbance due to land grading did not adversely affect yield. For specific
runoff events occurring in early spring, sediment yield per cm of runoff on the
original ungraded watershed was 85 percent less when the land was planted to wheat
as compared to a fallow condition. After grading, the wheat-covered land yielded
only 15 percent as much sediment per cm of runoff as that produced by the original
watershed in wheat. The sediment yield per cm of runoff for the graded watershed
in wheat was only about 2 percent of the yield from the original fallow watershed.
76:02E-012
A PHYSICALLY-BASED MODEL TO PREDICT RUNOFF UNDER VARIABLE RAIN INTENSITY,
Hachum, A.Y. and Alfaro, J.F.
Utah State University, Agricultural and Irrigation Engineering Department, Logan,
Utah.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 16 p, 1 fig, 2 tab, 31 equ,
15 ref.
Descriptors: Infiltration, Rainfall, Model studies, Simulation analysis, Rain,
Rainfall intensity. Rainfall simulators, Rainfall-runoff relationships.
A review of literature revealed that there are many empirical and physically-based
models that have been proposed to analyze infiltration under different rainfall
conditions. However, the validity of these models is still unknown due to the
lack of experimental data to support them. A simple and universal physical model
capable of predicting the ponding time and the rain infiltration in soils is
presented. Basically, the model is an extension of the Green and Ampt approach
to analyze infiltration under variable rainfall patterns. Model applications for
a storm presented elsewhere (Smith 1972) is included as well as for a hypothetical
storm with a smooth-variable intensity rainfall pattern. The prediction of the
system behavior, for the first case, closely agrees with that of Smith (1972).
76:02E-013
SEDIMENT YIELD PREDICTION BASED ON WATERSHED HYDROLOGY,
Williams, J.R. and Berndt, H.D.
United States Department of Agriculture, Agricultural Research Service, P.O.Box
748, Temple, Texas.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 14 p, 3 tab, 22 equ, 12 ref.
Descriptors: Sediments, Sedimentation, Sediment yield, Model studies, Soil mois-
ture, Texas, Rainfall, Watersheds, Watershed management. Reservoir design.
Daily, monthly, and annual sediment yield can be predicted fairly accurately by
attaching a sediment yield model (MUSLE) to hydrologic models. A water yield
model based on SCS curve numbers and a soil moisture index is used to predict
daily runoff volumes. This model must be calibrated on a gaged watershed and
can then be used to extend short periods of record for the calibrated watershed
or to predict water yield for nearby ungaged watersheds. Peak flow rates are
18
-------
predicted for a few storms of various volumes using HYMO. To save computing time
these peak flow rates are related to their runoff volumes so that the peak rate
can be determined rapidly for each daily flow volume. MUSLE uses the predicted
daily runoff volume and peak rate to predict daily sediment yield. The runoff-
sediment model was tested on 26 watersheds in Texas. A comparison of measured
and predicted average annual sediment yields gave an R2 or 0.98. For eight of
the watersheds monthly measured and predicted sediment had an average R2 or 0.66.
Prediction accuracy generally increased with decreasing watershed area mainly
because point rainfall better represents actual rainfall as area decreases. The
monthly and annual standard deviations of measured and predicted sediment yield
compared closely for these eight watersheds. Close comparisons in standard
deviations indicate that the predictions are fluctuating properly although they
may not always agree well with measured amounts. Also the model predicted consis-
tently throughout the year—sediment was not overpredicted for certain seasons
and underpredicted for others.
76:02E-014
NUTRIENT TRANSPORT IN RUNOFF FROM SANDY SOILS,
Campbell, K.L.
Florida University, Department of Agricultural Engineering, Gainsville, Florida.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 20 p, 4 fig, "• tab, 5 ref.
Descriptors: Watersheds, Water quality, Water quality management, Nutrients,
Streamflow, Return flow, Phosphorus, Nitrogen.
Two agricultural watersheds were instrumented to determine water quantity and qual-
ity measurements. The upper watershed of 437 hectares was primarily in forest
cover with some pasture. The lower watershed of 208 hectares was mostly in inten-
sive agricultural crop production with some pasture. The following results are
from data collected between July, 1975 and June, 1976. 1. Nitrogen and phosphorus
loads in Streamflow were about proportional to the flow volume in the two water-
sheds. 2. The increased flow volume in the lower watershed occurred mostly dur-
ing storm periods and was probably primarily due to land use and topography dif-
ferences between the two watersheds. 3. There were only small average concentra-
tion changes between storm flow periods and low flow periods in both watersheds.
4. Partial nutrient balances indicate that nutrient losses in Streamflow are a
very small part of the total nutrient flow system in these two watersheds. Total
nitrogen and phosphorus losses in Streamflow were equivalent to about 5% of the
commercial fertilizer applied in each watershed. Nutrient loads in Streamflow
also were less than those contributed to the watersheds in precipitation during
the period.
76:02E-015
A SALINITY MANAGEMENT STRATEGY FOR STREAM-AQUIFER SYSTEMS,
Helweg, O.J. and Labadie, J.W.
California University, Department of Civil Engineering, Davis, California
Hydrology Papers, Colorado State University.- No. 84, p 41, February 1976. 38 fig,
11 tab, 25 ref.
Descriptors: Salt, Salinity, Irrigation, Irrigation effects, Groundwater, Model
studies, Simulation Analysis, Optimization, Economics.
One of the pressing problems facing the irrigation intensive areas of the world
is the increasing salinity of groundwater. Currently proposed solutions, such as
agricultural sewering and desalinization, require large capital investment. There
appear to be few available alternatives which are both low cost and effective in
controlling aquifer degradation from irrigation drainage. The ultimate result
in many areas may be abandonment of the groundwater resource and increasing depend-
ence on more expensive imported water. Presented herein is a cost-effective salin-
ity management technique which may be feasible for many stream-aquifer systems.
The basic idea is to encourage application of pumped water downstream of the well
from which it is pumped, rather than within its vicinity. In this way, a mechan-
ism is established for accelerating the downstream transport of salts in the
groundwater at a more rapid rate than would occur naturally tnrough convection
and dispersion, while still satisfying irrigation demands. The strategy is there-
fore referred to as the Accelerated Salt Transport (ASTRAN) Method. Salt accum-
19
-------
ulation can be controlled in this manner, while taking care that salt problems
are not simply transferred downstream.
20
-------
Section VI
WATER CYCLE
GROUNDWATER (GROUP 02F)
76:02F-001
STEADY NON-DARCIAN SEEPAGE THROUGH EMBANKMENTS,
Basak, P.
Punjab Agricultural University, Department of Civil Engineering, Ludhiana, India.
Journal of the Irrigation and Drainage Division, American Society of Civil Engin-
eers, Vol. 102, No. IR4, Proceedings Paper No. 12623, p 435-443, December 1976.
5 fig, 2 tab, 19 ref.
Descriptors: *Darcys law, *Discharge (Water), *Free surfaces, *Seepage, *Aquifer
characteristics, Drainage, Water table, Steady flow, Velocity, Analysis, Flow
resistance, Porous media, Reynolds number.
A steady-state analytical solution for the case of unconfined flow through
embankments incorporating Forchheimer's nonlinear velocity-gradient response
was presented. The effect of nonlinearity on the discharge characteristics
and drawdown distribution in relation to the corresponding Darcian case was
brought out. Predicted discharge by means of the derived analytical solution
was campared with the available finite difference solution and experimental
results.
76:02F-002
TRANSIENT DRAINAGE WITH NONLINEARITY AND CAPILLARITY,
McWhorter, D.B., Duke, H.R.
Colorado State University, Department of Agricultural Engineering, Fort Collins,
Colorado.
Journal of the Irrigation and Drainage Division, American Society of Civ;.!
Engineers, Vol. 120, No. IR2, Proceedings Paper 12185, p 193-204, June 1976.
4 fig,_ 1 tab, 10 ref, 2 append.
Descriptors: *Equations, *Drainage, *Drains, *Groundwater movement, *Unsaturated
flow, Water table, Mathematical models, Unsteady flow. Mathematical studies,
Flow.
A nonlinear partial differential equation was developed that includes the effects
of capillary storage and flow above the water table. An approximate analytic
solution was derived. The water table response at the midpoint between drains
affected by capillary storage flow above the water table, and the nonlinearity
due to decreasing flow depth was predicted by one relatively simple expression.
Indices to the degree of importance of each of these three effects were defined.
It was concluded that appropriate simplified forms of the solution can be selec-
ted based on the value of the indices. The method is applicable to a wide range
of conditions including drains placed at any elevation relative to the impervi-
ous substratum and for shallow as well as deep water tables. The method removes
three important restrictions necessarily imposed on the classical and desirable
features. The equations are sufficiently simple to permit computations with a
calculator and should be useful on routine design calculations.
76:02F-003
WATER QUALITY AS RELATED TO LINEARS, ROCK CHEMISTRY, AND RAIN WATER CHEMISTRY
IN A RURAL CARBONATE TERRAIN,
Wagner, G.H., Steele, K.F., MacDonald, H.C., and Coughlin, T.L.
Arkansas University, Department of Geology, Fayetteville, Arkansas.
Journal of Environmental Quality, Vol. 5, No. 4, p 444-451, October-December
1976. 4 fig, 5 tab, 12 ref.'
Descriptors: Water quality, Precipitation, Rain water, Carbonate, Arkansas,
Trace elements. Aquifers, Nitrate, Fertilizers, Spring waters, Wells.
21
-------
Water from wells, springs, and streams from a 259 sq km area in rural, carbonate
terrain of northwest Arkansas was analyzed for Na, K, Ca, Mg, N03, P04, and trace
metals, Fe, Co, Cr, Ni, Cu, Zn, Cd, Pb, Mn, Li, and Sr. Bacterial counts for
total coliform, fecal coliform, and fecal streptocci, were also made. The same
area was mapped for linears by means of aerial photographs and field observa-
tions. Average rain water chemistry was determined for the year of 1974 when
the various water sources were sampled. The average chemical composition of the
St. Joe Limestone Member of the principal aquifer was determined from 22 samples
collected in northwest Arkansas. Water sources on linears had higher nitrate and
were more bacteriologically contaminated than those off linears. Trace metals
pollution was negligible in all waters except for copper and zinc which were
high due to contamination from household plumbing. Rain water is the main source
of trace metals for wells, springs, and streams, and limestone is the main source
of Ca and Mg. Rain water is a prime source of Na and K; however, clay, shale,
animal waste, and agricultural fertilizer probably also contribute Na and K.
76:020-004
ONE-DIMENSIONAL SIMULATION OF AQUIFER SYSTEM COMPACTION NEAR PIXLEY, CALIFORNIA:
II. STRESS-DEPENDENT PARAMETERS,
Helm, D.C.
Geological Survey, Menlo Park, California.
Water Resources Research, Vol. 12, No. 3, p 375-391, June 1976. 12 fig, 1 tab,
22 ref.
Descriptors: *Land subsidence, *Model studies, *Aquifer systems, California,
Methodology, Aquitards, Hydraulic conductivity, Specific retention, Water stor-
age, Compaction, Aquifer characteristics, *Simulation analysis, Computer models.
A major problem facing hydrologists is how to predict land subsidence. A key
to this problem is the development of a reliable method for evaluating aquitard
parameters. For assumed values of hydraulic conductivity and storage, vertical
compaction and expansion of idealized aquitards can be computed (predicted) by
an appropriate diffusion equation from known (projected) water level changes in
adjacent aquifers. If water levels within the aquifers are observed and the
resulting field compaction and expansion are measured, the parameters themselves
can be evaluated. Such field measurements are available at a site near Pixley,
California, for the composite behavior of a series of 21 doubly draining aqui-
tards. By means of a linear partial differential equation with constant coef-
ficients within one digital model, average hydraulic conductivity for idealized
aquitards was evaluated from the field data to be 3,000 ft/yr, and average non-
recoverable compaction to be stress dependent by assuming for any single mater-
ial that the product of hydraulic conductivity and an incremental effective
stress is a constant and that the product of nonrecoverable specific storage
and past maximum effective stress is a constant.
76:02F-005
DETERMINATION OF THE HYDRAULIC CONDUCTIVITY - DRAINABLE POROSITY RATIO FROM
WATER TABLE MEASUREMENTS,
Skaggs, R.W.
North Carolina State University, Department of Biological and Agricultural
Engineering, Raleigh, North Carolina.
Transactions of the American Society of Agricultural Engineers, Vol 19 No 1
p 73-84, January-February 1976. 13 fig, 25 ref. '
Descriptors: *Hydraulic conductivity, *Porosity, *Specific yield, *Water table,
Drawdown, Drainage systems, Groundwater movement. Drains, Dupuit-Forcheimer theory
Equations, Numerical analysis, Computers, Measurement, Graphical analysis,
Heterogeneity, Anisotropy, Evapotranspiration, Saturated flow.
A method was presented for determining field effective values of the hydraulic
conductivity-drainable porosity (K/f) ratio from water table measurements. Solu-
tions were presented in graphical form for parallel drains and for a single drain
in a semi-infinite medium. K/f can be determined from these solutions from either
water table drawdown or rise measurements. Solutions were also presented for
simultaneous drainage and vertical losses and may be used to evaluate the effect
of evapotranspiration or deep seepage on K/f determinations. Errors due to un-
22
-------
accounted vertical losses can be minimized by making water table measurements
close to the drain.
76:02F-006
A THREE-DIMENSIONAL GALERKIN FINITE ELEMENT SOLUTION OF FLOW THROUGH MULTIAQUI-
FERS IN SUTTER BASIN, CALIFORNIA,
Gupta, S.K., and Tanji, K.K.
California University, Department of Water Science and Engineering, Davis,
California.
Water Resources Research, Vol. 12, No. 2, p 155-162, April 1976. 6 fig, 1 tab,
9 ref. (Project UCAL-WRC-W438).
Descriptors: *Leakage, *Aquitards, Model studies, *Finite element analysis,
*California, Aquifers, Groundwater movement, Groundwater basins, Heterogeneity,
Dissolved solids, Connate water, Water quality, Digital computers, Equations,
Groundwater, Data processing, Faults (Geologic), Hydraulic conductivity. Water
table, Aquifer systems.
A three-dimensional finite element solution was obtained for the simultaneous
consideration of multiaquifers coupled through semiconfining layers, and the
model was applied to-a groundwater regime in Sutter Basin, California. The use
of a disk/tapeJLn data handling and computation has reduced the core storage and
processor time and increased the capability of a given computer system to simu-
late basins larger than are presently possible with the use of only core stor-
age. This economy was achieved by storing on a disk/tape all the intermediate
results which are needed repeatedly. On the Burroughs B6700 each steady state
solution of 123 three-dimensional elements and 232 nodes was obtained with 20
kbit of memory and 1.49 min of processor time.
76:02F-007 ^-
THEORY OF MULTIPLE LEAKY AQUIFERS I. THE INTEGRODIFFERENTIAL AND DIFFERENTIAL
EQUATIONS FOR SMALL AND LARGE VALUES OF TIME,
Rodarte, L.
Universidad Nacional Autonoma de Mexico, Institute de Ingenieria, Mexico City,
Mexico.
Water Resources Research, Vol. 12, No. 2, p 163-170, April 1976. 2 fig, 16 ref.
Descriptors: *Leakage, *Aquifers, *Aquicludes, *Aquitards, *Mathematical models,
Equations, Theoretical analysis, Mathematical studies. Drawdown, Water wells,
Pumping, Permeability, Aquifer systems, Elasticity (Mechanical), Time, Artesian
heads.
The general problem of multiple leaky aquifers was analyzed by using a particu-
lar problem as a starting point. Differential and integrodifferential equations
for small and large values of time, valid for the analysis of multiple leaky
aquifers, were obtained. The proposed equations are appropriate for both the
numerical and the analytic treatment of the regional evolution of the piezometric
loads.
76:02F-008
ON THE GENERAL EQUATIONS FOR FLOW IN POROUS MEDIA AND THEIR REDUCTION TO DARCY'S
LAW,
Gray, W.G., and O'Neill, K.
Princeton University, Department of Civil Engineering, Princeton, New Jersey.
Water Resources Research, Vol. 12, No. 2, p 148-154, April 1976. 1 fig, 15 ref,
append. NSF ENG75-16072 and NSF-RANN 6064.
Descriptors: *Groundwater, Equations, *Darcy's Law, Mathematics, *Flow, Subsur-
face waters, Groundwater movement, Groundwater potential, Pore water, Energy
equation. Momentum equation, Mathematical studies, *Porous media, Mass transfer,
Convection, Dispersion.
A technique of local averaging was applied to obtain general equations which
describe mass and momentum transport in porous media. The averaging was performed
without significantly idealizing either the porous medium or the pertinent fluid
mechanical relations. The resulting general flow equation was simplified to
23
-------
treat flow of a Newtonian fluid in a slowly deforming solid matrix for two
special cases. For flow in an isotropic medium where convective and inertial
terms are important, an equation was developed which is dependent only on five
medium parameters which could be evaluated by experiment. Flow in an anisotropic
medium was also analyzed, and the general equation was reduced to Darcy's law
when the convective and inertial terms were neglected.
76:02F-009
THE EXTENDED BOUSSINESQ PROBLEM,
Collins, M.A.
Southern Methodist University, Institute of Technology, Dallas, Texas.
Water Resources Research, Vol. 12, No. 1, p 54-56, February 1976. 5 fig, 1 ref.
Descriptors: *Water table, *Drains, *Groundwater movement, Leakage, Groundwater
recharge, Saline water-freshwater interfaces, Aquifers, Groundwater, Continuity
equation, Dupuit-Forchheimer theory. Boundary processes, Potentiometric level,
Equations, Islands, Depth.
The original Boussinesq problem of the decline of a groundwater mound between
parallel drains was extended to include vertical leakage and recharge and cases
of freshwater lenses in confined and unconfined saline aquifers. The solution of
appropriate continuity equations with some imposed restrictions by variable sep-
aration resulted in three distinct flow depth configurations, which could be
described analytically- Transient behavior in two of these cases is nonlinear
but amenable to exact solution and can be delineated in a (2 mu + beta, sigma +
mu) plane, where beta and sigma are leakage and recharge parameters and mu is a
separation constant. It was found that similarity solutions, one of which is
the original Boussinesq solution, exist for both decreasing and increasing flow
depths. Active and passive influences of boundary conditions were distinguished.
Solutions were applied to the evaluation of saline water intrusion in some coastal
zones of Long Island, New York.
76:02F-010
FLOW INTERFERENCE EFFECTS AT FRACTURE INTERSECTIONS,
Wilson, C.R., and Witherspoon, P.A.
Leeds, Hill, and Jewett, Incorporated, San Francisco, California.
Water Resources Research, Vol. 12, No. 1, p 102-104, February 1976. 4 fig, 1 ref.
Descriptors: *Groundwater movement, *Fracture permeability, *Model studies,
Hydraulic models. Flow, Laminar flow, Fractures (Geologic), Cracks, Rocks,
Hydrology, Hydraulics, Laboratory tests, Hydrogeology, Subsurface waters,
Groundwater.
A series of laboratory experiments were conducted to determine the magnitude of
laminar flow interference effects at fracture intersections. Circular conduits
were used in these experiments to maintain strict dimensional tolerance, and the
intersection head loss, if expressed in terms of equivalent length of straight
conduit, should be the same order of magnitude for a circular pipe as for a
parallel plate fracture model. The results indicated that interference effects
at intersections are negligibly small in most fracture systems when flow is in
the laminar regime.
76:02F-011
DETERMINING AQUIFER TRANSMISSIVITY BY MEANS OF WELL RESPONSE TESTS: THE UNDER-
DAMPED CASE,
van der Kamp, G.
Department of the Environment, Inland Waters Directorate: and Department of the
Environment, Hydrology Research Division, Ottawa, Ontario, Canada.
Water Resources Research, Vol. 12, No. 1, p 71-77, February 1976. 2 fig, 3 tab,
7 ref.
Descriptors: *Aquifer testing, *Transmissivity, *Theoretical analysis. Aquifer
characteristics. Water levels, Well filters, Equilibrium, Equations, Water
level fluctuations, Well casings, Aquifers, Artesian heads, On-site data collect-
ions.
24
-------
Well response tests, often referred to as slug tests, provide a relatively simple
and inexpensive method for estimating aquifer transmissivity. An approximate
theory was developed for the problem of underdamped well response where the
inertia of the water in the well column results in force-free oscillation of the
water level in the well. This type of response is often encountered in conjunct-
ion with highly permeable aquifers. The theory is applicable for nearly all such
cases except those where the oscillation is very quickly damped out. Theoreti-
cal predictions compared well with empirical results and indicated that the theory
may be used to obtain estimates of aquifer transmissivity. This theory for the
underdamped case together with existing theory for overdamped response makes it
possible to obtain an estimate of transmissivity from well response tests for
almost any aquifer.
76:02F-012
TRANSIENT FREE SURFACE FLOW TO A WELL: AN ANALYSIS OF THEORETICAL SOLUTIONS,
Gambolati, G.
Centro di Ricerca IBM di Venfezia, Italy.
Water Resources Research, Vol. 12, No. 1, p 27-39, February 1976. 12 fig, 1 tab,
59 ref.
Descriptors: *Unsteady flow, *Water table aquifers, *Equations, Storage coeffi-
cient, Specific yield, Water wells, Drawdown, Groundwater, Stress, Pressure head,
Theis equation, Dupuit-Forchheimer theory.
Results based on linearization and on the delayed yield concept provide the most
theoretical advancements to date for solving the differential equations of trans-
ient free surface flow to a fully penetrating gravity well. If the storage coef-
ficient is markedly less than the specific yield, vertical flow is predominant
in a cylindrical zone of the water table between two regions where flow is essen-
tially radial and controlled by two different Theis equations. The true physical
alpha (reciprocal of Boulton's delay index) is found to vary almost linearly with
the reciprocal of the distance from the pumped well and becomes a constant at
some distance (equal to twice the aquifer thickness if the medium is isotropic).
An empirical delay index is also found by equating Boulton's solution and the
linearized average drawdown. Its expression enables the use of the delayed yield
solution in computing average drawdowns With an accuracy equal to that of the
linearization approach. The present solutions assumed small water table draw-
downs and an infinite aquifer.
76:02F-013
AN INTEGRATED FINITE DIFFERENCE METHOD FOR ANALYZING FLUID FLOW IN POROUS MEDIA,
Narasimhan, T.N., and Witherspoon, P.A.
California University, Department of Civil Engineering, Berkeley, California.
Water Resources, Research, Vol. 12, No. 1, p 57-64, February 1976. 10 fig,
30 ref.
Descriptors: *Numerical analysis, *Groundwater movement, *Porous media, Heat
transfer, Stability, Conduction, *Finite element analysis, Flow, Equations,
Potential flow, Theis equation. Fracture permeability. Mathematical studies,
Computers•
The theoretical basis for the integrated finite difference method (IFDM) was
presented to describe a powerful numerical technique for solving problems of
groundwater flow in porous media. The method combines the advantages of an
integral formulation with the simplicity of finite difference gradients and
is very convenient for handling multidimensional heterogeneous systems composed
of isotropic materials. Three illustrative problems were solved to demonstrate
that two- and three-dimensional problems are handled with equal ease. Compari-
son of IFDM with the wellknown finite element method (FEM) indicated that both
are conceptually similar and differ mainly in the procedure adopted for measur-
ing spatial gradients. The IFDM includes a simple criterion for local stability
and an efficient explicit-implicit iterative scheme for marching in the time
domain. If such a scheme can be incorporated in a new version of FEM, it should
be possible to develop an improved numerical technique that combines the inherent
advantages of both methods.
25
-------
76:02F-014
DYNAMIC RESPONSE OF AQUIFER SYSTEMS TO LOCALIZED RECHARGE,
Cabrera, G., and Marino, M.A.
Chile University, Centro de Recursos Hidraulicos, Santiago, Chile.
Water Resources Research, Vol. 12, No. 1, p 49-63, February 1976. 7 fig,
18 ref.
Descriptors: *Recharge, *Streams, *Aquifers, *Finite element analysis, *Computer
programs, Surface-groundwater relationships. Numerical analysis, Hydraulics,
*Flow system, *Model studies, Analytical techniques. Base flow.
The response of stream-unconfined aquifer systems to localized recharge was
investigated by means of a two-dimensional finite element model. A variational
approach was used in conjunction with the finite element method to solve the
ground-water flow equation. Linear approximated triangular elements were used
to calculate the hydraulic head distribution in the flow region. The Crank-
Nicholson centered scheme of numerical integration was employed to approximate
the time derivative in the flow equation. A computer program was developed to
calculate the hydraulic head distribution in the flow region. Solutions provided
by the finite element model should prove 'useful in the evaluation of quantitative
and qualitative changes in aquifer systems due to natural or artificial recharge.
In addition, they should pr6ve useful in the study of irrigation and drainage
problems.
6:02F-015
ONE-DIMENSIONAL SIMULATION OF AQUIFER SYSTEM COMPACTION NEAR PIXLEY, CALIFORNIA:
II. STRESS-DEPENDENT PARAMETERS,
Helm, D.C.
Geological Survey, Menlo Park, California.
Water Resources Research, Vol. 12, No. 3, p 375-391, June 1976. 12 fig, 1 tab,
22 ref.
Descriptors: *Land subsidence, *Model studies, *Aquifer systems, *California,
Methodology, Aquitards, Hydraulic conductivity, Specific retention, Water
storage. Compaction, Aquifer characteristics, *Simulation analysis. Computer
models.
A major problem facing hydrologists is how to predict land subsidence. A key
to this problem is the development of a reliable method for evaluating aquitard
parameters. For assumed values of hydraulic conductivity and storage, vertical
compaction and expansion of idealized aquitards can be computed (predicted) by
an appropriate diffusion equation from known (projected) water level changes in
adjacent aquifers. If water levels within the aquifers are observed and the
resulting field compaction and expansion are measured, the parameters themselves
can be evaluated. Such field measurements are available at a site near Pixley,
California, for the composite behavior of a series of 21 doubly draining aqui-
tards. By means of a linear partial differential equation with constant coeffi-
cients within one digital model, average hydraulic conductivity for idealized
aquitards was evaluated from the field data to be 3000 ft/yr, and average non-
recoverable specific storage was evaluated to be 0.00023 ft. A second model
allows parameters of nonrecoverable compaction to be stress dependent by assum-
ing for any single material that the product of hydraulic conductivity and an
incremental effective stress is a constant and that the product of nonrecoverable
specific storage and past maximum effective stress is a constant.
76:02F-016
ANALYSIS OF AQUIFER-AQUITARD FLOW,
Streltsova, T.D.
Birmingham University, Department of Civil Engineering, Birmingham, England.
Water Resources Research, Vol. 12, No. 3, p 415-422, June 1976. 8 fig, 15 ref.
Descriptors: *Equations, *Aquifers, *Aquitards, *Groundwater movement, *Draw-
down, Water wells, Water table, Leakage, Flow system, Hydraulic properties,
Graphical analysis, Mathematical studies, Permeability, Storage coefficient,
Specific yield, Flow.
26
-------
The general drawdown equation and its particular cases were considered for a
partially penetrating well discharging at a constant rate from an aquifer which
is overlain by an aquitard containing the water table. An identity was estab-
lished between the exact solutions, developed in terms of the rho = mu(r)/h
parameter, and those based on the finite difference approximation, developed in
terms of the r/B parameter. The relations in the rho and the r/B parameter were
given for a well of complete penetration. The quasi-steady drawdown equation
was developed for a well of partial penetration in an aquifer-aquitard flow
system. The solution was graphically presented, and its use in the distance-
drawdown curve-matching procedure was described. Determination of the aquifer-
aquitard formation constants was discussed.
76:02F-017
A PROPOSED ALGORITHM FOR THE SOLUTION OF THE LARGE-SCALE INVERSE PROBLEM IN
GROUNDWATER,
Chang, S., and Yeh, W.W-G.
California University, Department o*. Engineering Systems, Los Angeles,
California.
Water Resources Research, Vol. 12, No. 3, p 365-374, June 1976. 4 fig, 7 tab,
23 ref. (California Water Resources Center project W290).
Descriptors: *Algorithms, *Groundwater, Flow, *Mathematical models, Constraints,
Equations, Least squares method. Systems analysis, *Model studies, *Base flow.
A new algorithm is introduced for the solution of the problem of parameter
identification associated with a two-dimensional unsteady state groundwater
flow. The parameters to be identified are functions of the space variables. It
is assumed that some observations on the dependent variable of the governing
equation are available. The unknown parameters are directly identified from
observations. An implicit finite difference scheme is used to approximate the
original partial differential equation. A least squares criterion function is
employed. The identification problem is then formulated as a standard quadratic
programming representation by quasi-linearization. The formulation is further
modified by a simple matrix operation which drastically reduced the.dimension of
the constraint set. The new algorithm is shown to be very effective in solving
the large-scale inverse problem, and it is easily implemented, rapidly conver-
gent, and able to handle any inequality constraints, a feature that is essential
for such a problem. '
76.-02F-018
HYDRODYNAMICS OF GROUNDWATER FLOW IN A FRACTURED FORMATION,
Streltsova, T.D.
Birmingham University, Department of Civil Engineering, Birmingham, England.
Water Resources, Research, Vol. 12, No. 3, p 405-414, June 1976. 9 fig, 3 tab,
31 ref, 1 append.
Descriptors: *Groundwater movement, *Hydrodynamics, *Equations, *Fractures
(Geologic), Hydraulic properties, Aquifers, Aquitards, Elasticity (Mechanical),
Homogeneity, Heterogeneity, Drawdown, Testing, Pumping, Porous media. Fissures
(Geologic), Graphical analysis. Mathematical studies, Rock properties.
Hydrodynamical aspects of groundwater flow in fractured formations and the basic
hydraulic properties controlling the flow were considered. A brief literature
survey on studying the physical characteristic of the fractured rocks and on
developing an understanding on the mechanism of fluid flow in fracture formations
constituted an introductory section. Basic definitions, relations, and assump-
tions given for subsequent interpretation of the flow behavior in a fissured
rock then followed. Concepts of fractured, homogeneous, and heterogeneous water-
bearing formations and their response mechanism to a pressure change were consi-
dered. The general differential equations for a flow in a fractured and in a
heterogeneous formation of uniform anisotropy were derived. Two types of the
flow behavior.- fissure flow and pore flow, were distinguished. Two drawdown
equations, respectively, for a flow in a fissure space, whether void or infilled
with a fine material, and for a flow in a porous space to a well discharging at
a constant rate in a fractured aquifer, were given. A fractured reservoir
response to a pressure change due to pumping was illustrated by the field draw-
down and recovery data. A particular case of a heterogeneous formation, an
27
-------
aquifer-aquitard system, was discussed, and the drawdown distribution in both
aquifer and aquitard was given when account is taken of their elastic properties.
76:02F-019
A SLUG TEST FOR DETERMINING HYDRAULIC CONDUCTIVITY OF UNCONFINED AQUIFERS WITH
COMPLETELY OR PARTIALLY PENETRATING WELLS,
Bouwer, H., and Rice, R.C.
Agricultural Research Service, Water Conservation Lab, Phoenix, Arizona.
Water Resources Research, Vol. 12, No. 3, p 423-428, June 1976. 4 fig, 11 ref.
Descriptors: *Hydraulic conductivity, *Aquifer testing, *Aquifers, *Water wells,
*Theims equation, Water levels, Resistance networks, Analog models, Equations,
Transmissivity, Water table aquifers, Water table, Potentiometric level, Perm-
eability, Equilibrium.
A procedure was presented for calculating the hydraulic conductivity of an aqui-
fer near a well from the rate of rise of the water level in the well after a
certain volume of water is suddenly removed. The calculation was based on the
Thiem equation of steady state flow to a well. The effective radius R sub e
over which the head difference between the equilibrium water table in the aqui-
fer and the water level in the well is dissipated was evaluated with a resis-
tance network analog for a wide range of system geometries. An empirical
equation relating R sub e to the geometry of the well and aquifer was derived.
It was discovered that the technique is applicable to completely or partially
penetrating wells in unconfined aquifers; it can also be used for confined
aquifers that receive water from the upper confining layer. The method's results
were compatible with those obtained by other techniques for overlapping geomet-
76:02F-020
PREDICTION OF MOUND GEOMETRY UNDER RECHARGE BASINS,
Singh, R.
San Jose State University, San Jose, California.
Water Resources Research, Vol. 12, No. 4, p 775-780, August 1976. 8 fig, 17 ref.
NSF GK-18526
Descriptors: *Groundwater recharge, *Unsteady flow, *Laplaces equation, Recharge,
Mathematical studies, Water table. Porous media, Dimensional analysis. Analysis,
Computers, Groundwater, Graphical analysis, Equations.
Design of recharge facilities close to urban centers required determination of
the transient water table in the vicinity of the recharge site. This involves
solution of the Laplace equation subject to appropriate boundary and initial
conditions which are nonlinear and extremely complex for a phreatic surface with
or without accretion. Previous solutions have been obtained either by linear-
ization of the phreatic surface conditions or by utilization of other simplify-
ing assumptions. These solutions are usually inapplicable in regions with steep
hydraulic gradients. A technique for computing the transient location of the
water table under finite width longitudinal and circular recharge basins was
developed. The technique avoided limiting assumptions and linearization. The
computations were carried out on a digital computer. Results were presented
graphically and compared with other solutions where appropriate.
76:02F-021
ON THE SPECIES TRANSPORT EQUATION FOR FLOW IN POROUS MEDIA,
Blake, T.R., and Garg, S.K.
Systems, Science, and Software, La Jolla, California.
Water Resources Research, Vol. 12, No. 4, p 748-750, August 1976. 7 ref. NSF/
RANN GI-44212.
Descriptors: *Porous media, *Continuity equation, *Theoretical analysis.
Diffusion, Mixing, Equations, Analysis, Fluid mechanics. Momentum equation,
Flow, Convection, Solutes.
A derivation of the species transport equation for flow through porous -media was
presented. In this study, which was based on the snace-averaging formalism
28
-------
developed by Anderson and Jackson, the effects of both flow field fluctuations
and tortuosity as well as the influence of solute transport at the fluid-solid
interfacial boundary were examined.
76:02F-022
A NUMERICAL STUDY OF CONFINED-UNCONFINED AQUIFERS INCLUDING EFFECTS OF DELAYED
YIELD AND LEAKAGE,
Ehlig, C., and Halepaska, J.C.
Kansas State Geological Survey, Lawrence, Kansas.
Water Resources Research, Vol. 12, No. 6, ; 1175-1183, December 1976. 13 fig,
13 ref.
Descriptors: *Groundwater, *Aquifers, *Model studies, Mathematical models,
Pumping, Drawdown, Confined water. Wells, Water wells. Hydraulic conductivity,
Water yield, Leakage, Transmissivity, Permeability, Groundwater movement.
A numerical model is presented in radial coordinates for a well penetrating a
homogeneous isotopic aquifer of constant thickness. The model defined varia-
tions in the transmissivity and effective storage coefficient as functions of
the potential. This allowed an approximation for the problem of a well pumping
in an initially confined system, which becomes unconfined near the well as the
potential surface drops below the confining layer of the aquifer (confined-un-
confined problem). The model was used to investigate effects of delayed yield
and leakage confined-unconfined aquifers. Drawdown versus time curves were
presented for a variety of boundary conditions. Results showed that the condi-
tions producing an inflection in the drawdown versus curves are not unique and
illustrates the difficulty in attempting to determine aquifer characteristics
from pumping test.
76:02F-023
A SINGLE-POTENTIAL SOLUTION FOR REGIONAL INTERFACE PROBLEMS IN COASTAL AQUIFERS,
Strack, O.D.L.
Minnesota University, Department of Civil and Mineral Engineering, Minneapolis,
Minnesota.
Water Resources Research, Vol. 12, No. 6, p 1165-1174, December 1976. 11 fig,
15 ref.
Descriptors: *Saline water intrusion, *Saline water-freshwater interfaces,
*Aquifers, *Coasts, Groundwater, Groundwater movement. Model studies. Mathemati-
cal models, Sea water. Equations, Wells, Water wells. Brackish water,- Interfaces,
Subsurface waters.
An analytic technique for solving three-dimensional interface problems in coastal
aquifers was presented. Restriction was made to cases of steady state flow with
homogeneous isotopic permeability where the vertical flow rates can be neglected
in relation to the horizontal ones. The aquifer was divided into zones defined
by the type of flow occurring. These types of flow may be either confined,
unconfined, confined interface, or unconfined interface flow, where the inter-
faces separate freshwater from salt water at rest. The technique is based upon
the use of a single potential which is defined throughout all zones of the aqui-
fer. The potential is single valued and continuous throughout the multiple-zone
aquifer, and its application does not require that the boundaries between the
zones be known in advance. , The use 6£ the single-valued potantial was illustra-
ted for an analytical technique, but it may be used with some advantage in
numerical methods such as finite difference or finite element techniques. Appli-
cations discussed involve two interface flow problems in a shallow coastal aqui-
fer with a fully penetrating well. The first problem is one of unconfined inter-
faces flow where the upper boundary is a free water table. The second is one of
unconfined interface flow where the upper boundary is horizontal and inpervious.
Each problem involves two zones. One zone is adjacent to the coast and is
bounded below by an interface between freshwater and salt water at rest. The
other zone is bounded below by an impervious bottom.
76:02F-024
MAJOR CARBON 14 ANOMALY IN A REGIONAL CARBONATE AQUIFER: POSSIBLE EVIDENCE FOR
MEGASCALE CHANNELING, SOUTH CENTRAL GREAT BASIN,
29
-------
Winograd, I.J., and Pearson, F.j. Jr.
Geological Survey, Water Resources Division, Reston, Virginia.
Water Resources Research, Vol. 12, No. 6, p 1125-1143, December 1976.
Descriptors: *Geochemistry, *Water qualtiy, *Groundwater, *Springs, *Carbonate
rocks, Aquifers, Faults (Geologic), Nevada, Trace elements.
The carbon 14 content of groundwater at the center of a 16-km-long fault-con-
trolled spring line at Ash Meadows in south-central Nevada is 5 times greater
than that in water from other major springs along the lineament. The difference
in carbon 14 stands in marked contrast to the near identity of all springwaters
in alkalinity, pH, carbon 13, oxygen 18, deuterium, tritium, and other major and
trace ions. The possible explanations of this major carbon 14 anomaly are evalu-
ated by using all available chemical and isotopic data from basin-wide wells and
upland springs tapping the regional carbonate aquifer discharging at Ash Meadows.
The four most plausible hypotheses require the presence of a major longitudinal
heterogeneity in the distal portion of the groundwater basin to explain the
anomaly. Flow channeling with an amplitude of at least 11 km is indicated. The
simplifying assumption commonly used in simulation of basin-wide flow through
fractured or solution-riddled aquifers, namely, that the aquifer is "homogenous
in its heterogeneity" is not applicable to the dense fractured- Paleozoic carbon-
ate rocks comprising the Nevada aquifer; heterogeneities in this aquifer do not
cancel each other areally.
76:02F-025
DUPUIT-FORCHHEIMER AND POTENTIAL THEORIES FOR RECHARGE FROM BASINS,
Brock, R.R.
California State University, Department of Civil Engineering, Fullerton,
California.
Water Resources Research, Vol. 12, No. 5, p 909-911, October 1976. 5 fig,
9 ref. OWRT C-3112(3687)(3).
Descriptors: *Dupuit-Forchheimer theory, *Potential flow, *Groundwater
recharge, *Pit recharge, Artificial recharge. Water table, Equations, Ground-
water movement, Theoretical analysis, Water level fluctuations. Water table
aquifers, Groundwater basins, Percolation, Pores, Mathematical models.
Artificial groundwater recharge from strip and square basins to an unconfined
aquifer was investigated. The classical Dupuit-Forchheimer (DF) theory and the
most exact potential theory were used to determine the motion of the water
table resulting from recharge. For each theory, both a linear and a nonlinear
version were considered. Finite difference schemes were employed to solve for
the nonlinear models. Analytical solutions exist for the linear models. By
comparing the results from the various theories and from experimental results
in a sand model, the range of validity of the theories was determined. For
sufficiently shallow flows, the DF theories gave results that are good approx-
imations to the potential theories. For sufficiently deep flows, the poten-
tial theories must be used, particularly beneath the basin and for small times.
The velocity field near a strip basin was determined from the nonlinear poten-
tial theory for both a deep and a shallow flow. Tabular results were presented
that can be used to determine the rise of the water table for strip and square
basins.
76:02F-026
NUMERICAL PREDICTIONS OF TWO-DIMENSIONAL TRANSIENT GROUNDWATER FLOW BY THE
METHOD OF CHARACTERISTICS,
Wiggert, D.C., and Wylie, E.B.
Michigan State University, Department of Civil Engineering, East Lansing,
Michigan.
Water Resources Research, Vol. 12, No. 5, p 971-977, October 1976. 12 fig,
1 tab, 31 ref. OWRT A-067-MICH(2).
Descriptors: *Groundwater movement, *Model studies, *Mathematical models,
Groundwater, Aquifers, Analytical techniques. Finite element analysis,
Numerical analysis. Base flow. Subsurface waters, Hydrogeology, *Forecasting.
30
-------
Unsteady flow in a confined or leaky aquifer can be analyzed by replacing the
two-dimensional space domain with a latticework of line elements which inter-
sect at nodal points. Continuity and momentum principles were applied to each
line element separately, resulting in a system of hyperbolic equations which
can be solved by the method of characteristics. Upon combination of the con-
tinuity relation and compatibility conditions at each node, an explicit solu-
tion for the time-variable piezometric heads and seepage velocities was ob-
tained. An inertial multiplier was introduced in the momentum equation, which
varies inversely with the magnitude of the fluid acceleration. The time step,
proportional to the multiplier, thus assumes large values, while the method
continues to provide accurate, stable results. Numerical examples were compared
with analytical solutions, and a nonhomogeneous regional aquifer analysis
agreed favorably with a finite element model. The numerical scheme provides
ease of programming, reduced computer storage requirements, and reasonable
central processing times.
76:02F-027
HYDROGEOPHYSICAL EQUIVALENCE OP WATER SALINITY, POROSITY AND MATRIX CONDUCTION
IN ARENACEOUS AQUIFERS,
Worthington, P.P.
National Physical Research Laboratory, Geophysics Division, Pretoria, South
Africa.
Ground Water, Vol. 14, No. 4, p 224-232, July-August 1976. 4 fig, 9 ref.
Descriptors: *Resistivity, *Salinity, *Porosity, *Sand aquifers, Sands,
Sandstones, Geophysics, Aquifer characteristics, Sodium chloride, Conduction,
Equations, Groundwater, Mapping, Curves, Heterogeneity, Graphical analysis,
Hydrogeology-
The value of the electrical resistivity method as a quantitative indicator of
groundwater resistivity, porosity, and effective matrix resistivity was examined
through the equivalence of these parameters as manifested in the surface-
measured resistivity of heterogeneous water-saturated sands. It was demon-
strated that, where there were unknown variations in porosity, the mapping of
groundwater resistivity was most feasible at lower salinities and where porosity
was relatively high. Porosity could be determined most exactly at lower values
and where groundwater salinity was relatively high. Both of these approaches
became less efficient as matrix conduction increases. The mapping of effective
matrix resistivity was best effected at lower values where this parameter could
be approximately monitored against moderate variations in both porosity and
groundwater resistivity. In general, however, where there were unknown and
pronounced variations in any two of these parameters, the geoelectrical deter-
mination of the third could be so ambiguous that the uncertainty in the
estimated value of this parameter could exceed the total range of values
encountered in an entire formation.
76:02P-028
EVALUATING GROUND-WATER PATHS USING HYDRAULIC CONDUCTIVITIES,
Naney, J.W., Kent, D.C., and Seely, E.H.
Agricultural Research Service, Chickasha, Oklahoma, Texas-Oklahoma Area.
Ground Water, Vol. 14, No. 4, p 205-213, July-August 1976. 14 fig, 13 ref.
Descriptors: *Hydraulic conductivity, *Groundwater, *Oklahoma, *Groundwater
movement, *Hydrogeology, Effluent streams, Flow nets, Mathematical models.
Watersheds (Basins), Subsurface flow, On-site investigations, Computer programs,
Potentiometric level. Seepage, Mapping, Cores, Pump testing, Particle size,
Permeameters, Model studies.
A method was presented for selecting groundwater flow paths by comparing
modeled and measured hydraulic conductivity distributions. A flow chart was
included which shows the steps followed in selecting the concept of roundwater
flow which best fits measured hydrogeologic conditions. Both noneffluent and
effluent stream conditions were evaluated using the method. Residual maps of
hydraulic conductivity were used to show how modeled hydraulic conductivity may
be as much as 300 times that expected when the wrong concept is used. Flow
nets of modeled and measured data downstream from a flood-water-retarding
31
-------
structure were developed using the selected hydrogeologic conditions. Fitting
hydraulic conductivity data resulted in a distribution of groundwater flow paths
which better represent actual flow conditions. The method provided a unique
means of calibrating a model in a pilot test area and applying it to geologically
similar nearby watersheds. It was also useful for checking paths of subsurface
flow where flow distribution is important as it is in the movement of chemical
pollutants or nutrients from a source of recharge, such as a watershed impound-
ment, to downstream waters.
76:02F-029
A SIMPLIFIED APPROACH FOR THE ANALYSIS OF UNSTEADY FLOW TO A CAVITY WELL,
Kanwar, R.S., Khepar, S.D., Chauhan, H.S., and Das, G.
Punjab Agricultural University, Department of Soil and Water Engineering, Ludhiana
(India).
Ground Water, Vol. 14, No. 2, p 101-105, March-April 1976. 3 fig, 1 tab, 9 ref.
Descriptors: *Groundwater, (Model studies, *Wells, *Aguifer characteristics,
Aquifers, Hydraulic conductivity. Storage coefficient, Unsteady flow, Drawdown,
Hydraulics.
An analytical solution obtained for unsteady flow to a cavity well has been
simplified for finding the aquifer characteristics. In the analysis presented,
the relationships become fairly simple for the close approximation of the unsteady
state solution. The simplified solution is of great importance for finding the
values of storage coefficient and hydraulic conductivity. This solution has
large important economic implications, since the formation constants of the
aquifer can be found without drilling in the aquifer and installing the screens.
If the values of S and K found from these relations are fairly satisfactory
after a pumping test, the other more expensive methods which require a fully
penetrating well may not be needed.
76:02F-030
SHAPES OF STEADY STATE PERCHED GROUNDWATER MOUNDS,
Khan, M.Y., Kirkham, D., and Handy, R.L.
Iowa State University, Department of Agronomy, Ames, Iowa 50011
Water Resources Research, Vol. 12, No. 3, p 429-436, June 1976. 6 fig, 2 tab,
21 ref.
Descriptors: Groundwater, Groundwater barriers, Groundwater resources, Aquifers,
Groundwater recharge, Flow n-^ts.
A potential theory flow solution for the potential function, stream function, and
shape of the water table is given for a class of steady state two- and three-dimen-
sional perched groundwater mounds formed under a long rectangular recharge basin
or under a circular recharge basin. The solutions are done by a Gram-Schmidt
method and a simple iteration scheme. The mounds are formed in a stratum of
conductivity kl overlying a perching stratum of much lower conductivity k2. Capil-
lary fringe effects are neglected. The recharge rate is R. Potential theory
mound heights are compared with those given by the Dupuit-Forchheimer (DF) theory.
For the cases computed, the DF theory gives apex heights of mounds correct to
better than 7% for two-dimensional mounds. For three-dimensional mounds the DF
theory gives in one case a mound height that is 69% too low and in another case
a mound height that is 28% too low. Profiles of the computed mounds are graphed,
and examples of use of the graphs in applications are given. Sample flow nets
are presented.
76:02F-031
DRAINAGE PRACTICE IN IMPERIAL VALLEY, CALIFORNIA,
Hermsmeier, L.F.
Imperial Valley Conservation Research Center, Department of Agricultural Engineer-
ing, Brawley, California.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 20 p, 7 tab, 13 ref.
Descriptors: California, Drainage, Drainage practices, Salinity, Return flow,
Crop production, Irrigation water. Seepage.
32
-------
Some of the unique equipment and procedures developed during the past 50 years
that have provided both low cost and effective drainage in the Imperial Valley
is described. In this valley, as in most irrigated areas, land drainage is essen-
tial to provide the salinity and water table control necessary for good crop pro-
duction. At present and in the future, increasing salinity and limited quantity
of irrigation water, restrictions on quantity and the amount of contaminants in
outflow and seepage water, and the need to provide improved growing conditions
are presenting new challenges for drainage design and construction. These chal-
lenges and possible solutions are discussed.
76:02F-032
WATER-TABLE MANAGEMENT,
Wenberg, R.D.
United States Soil Conservation Service, South Technical Service Center, Fort
Worth, Texas.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 7 p, 4 fig, 14 ref.
Descriptors: Drainage, Irrigation, Humid areas. Subsurface drainage, Subsurface
irrigation. Water table.
Water-table management as presented here is a combination of drainage and irriga-
tion for the humid section of the United States. Subsurface drainage is used to
lower the water table in coarse-textured soils and yields are improved by sub-
surface irrigation.
76:02F-033
UNSTEADY FLOW TO A NONPENETRATING ARTESIAN WELL,
Abdul Khader, M.H., and Ramadurgaiah, D.
Singapore University, Department of Civil Engineering, Singapore-10, Singapore.
Groundwater, Vol. 14, No. 4, p 200-204, July-August 1976. 5 fig, 2 tab, 9 ref.
Descriptors: Artesian wells, Groundwater, Aquifers, Artesian aquifers.
Exact solution to the problem of unsteady drawdown in a leaky artesian aquifer due
to a constant discharge nonpenetrating well is presented. Finiteness of the well
radius and aquifer anisotropy are considered in formulating the problem. Solution
is derived on the assumption that the flux entering the pumped well is uniformly
distributed over the plane circular bottom of the well. The aquifer is considered
to be finite in thickness, but of infinite lateral extent. The flow of ground
water is assumed to be governed by Jacob's model of linear leakage. Laplace trans-
fromation technique is employed in the theoretical development. The drawdown
function is numerically integrated in terms of dimensionless parameters of the
flow system and the results are depicted in graphs.
76:02F-034
GROUNDWATER OF VOYVODINA, ITS QUALITY AND APPLICABILITY FOR IRRIGATION,
Zivkovik, B.
Faculty of Agriculture, Institut za Poljoprivredna Istrazivanja, Novi Sad, Yugo-
slavia.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 350-357. 1 fig, 1 tab, 9 ref.
Descriptors: Groundwater, Water quality, Dissolved solids. Irrigation water.
Saline soil, Salinity, Groundwater management.
On the basis of the results achieved in groundwater investigations and their
applicability in Voyvodina the following conclusions can be made: (1) Groundwater
in Voyvodina is mostly of poor quality, has a relatively high content of dissolved
salts, and should not be used for irrigation; (2) Underground water in the water-
sheds of the Danube, Tisza and Sava can be used for irrigation due to their good
quality; (3) In order to prevent further soil salinization it is necessary to
lower the groundwater level to a harmless depth which, due to the natural condi-
tions in Voyvodina, is 200-250 cm; and (4) It is important to provide expert
control both over the usage of the groundwater for irrigation and the control
of soil salinization.
33
-------
Section VII
WATER CYCLE
WATER IN SOILS (GROUP 02G)
76:02G-001
COUPLING PHENOMENA IN SATURATED HOMO-IONIC MONTMORILLONITE: I. EXPERIMENTAL,
Elrick, D.E., Smiles, D.E., Baumgartner, N., and Groenevelt, H.
Guelph University, Department of Land Resource Science, Ontario, Canada.
Soil Science Society of America Journal, Vol. 40, No. 4, p 490-491, July-August
1976. 3 fig, 2 ref.
Descriptors: *Clays, *Montmorillonite, *Soil physical properties, *Soil water
movement, Pressure, Salts, Sodium chloride. Electrical properties, Electrochem-
istry, Membranes, Laboratory tests, Soil water, Groundwater, Soil science.
A series of experiments was performed to observe the effects of salt concentra-
tion differences across a .thin layer of homo-ionic montmorillonite. The water
pressure difference, concentration difference, and voltage difference measured
with electrodes reversible to the anion were observed as functions of time. A
qualitative explanation of the observations was proposed.
76:02G-002
PERCOLATION OF SURFACE-APPLIED WATER IN THE FIELD,
Quisenberry, V.L., and Phillips, R.E.
Kentucky Agricultural Experimental Station, Lexington, Kentucky.
Soil Science Society of America Journal, Vol. 40, No. 4, p 484-489, July-August
1976. 10 fig, 10 ref.
Descriptors: *Percolation, *Soil water movement, *Soils, *Irrigation, Chlorides,
Tracers, Unsaturated flow, Groundwater movement, Infiltration, Percolating water,
Porosity, Soil moisture, Soil water, Topsoil, Loam, Clay loam, Rainfall, Agri-
culture.
Percolation of surface-applied water tagged with chloride was studied in Maury
silt loam and Huntington silty clay loam under field conditions. Soil samples
were taken in small increments to the 90-cm depth several times following appli-
cation of water. Analyses of chloride content with depth indicated the position
.of the applied water relative to the initial soil water in the profile. Three
percolation studies were conducted on Maury silt loam soil. In the first study,
an application of 4.2-cm of water increased the water content to the 60-cm depth
within 1 hour following irrigation even though volumetric water averaged 5% be-
low the upperlimit of the water holding capacity through this depth. A second
study conducted at a slightly higher initial water content showed that 20% of a
4.2-cm application had penetrated below the 90-cm depth immediately after appli-
cation and 40% penetrated below this depth within 1 hour. Similar results were
measured in Huntington silty clay loam. Simulated rainfall increased the water
content significantly to approximately the 15-cm depth in each of three studies.
A large percentage of the water passing this depth apparently percolated past
the 90-cm depth with very little adsorption of water and chloride between these
depths. Location of chloride in the profile and movement of chloride past the
90-cm depth indicated that a large percentage of the applied water percolated
past the water initially present with little displacement of the initial water.
76:02G-003
INFLUENCE OF HYSTERESIS ON MOISTURE FLOW IN AN UNDISTURBED SOIL MONOLITH,
Beese, F., and van der Ploeg, R.R.
Goettingen University, Institute of Soil Science and Forest Nutrition, West
Germany.
Soil Science Society of America Journal, Vol. 40, No. 4, p 480-484, July-August
1976. 8 fig, 17 ref.
Descriptors: *Soil moisture, *Hysteresis, *Drying, *Wetting, Soils, Podzols,
Gray-brown podzolic soils, Physical properties, Lysimeters, Infiltration, Unsat-
34
-------
urated flow, Soil properties, Soil water, Diffusion, Soil water movement, Mathe-
matical models. Model studies, Laboratory tests, Sorption, Soil science.
The moisture dynamics of an undisturbed soil monolith were studied during a
lysimeter experiment. Daily measurements were made of the soil suction at 10
depths. Also measured daily were the precipitation, the seepage, and the evap-
oration from the monolith during a 3-year period. For selected periods, a dry-
ing (desorption) curve and a wetting (sorption) curve of the soil moisture char-
acteristic were determined from field data. Also, the capillary conductivity
was determined with use of daily monolith observations. By using these hydraulic
functions, the unsaturated soil moisture flow equation was solved numerically
for one-dimensional vertical flow. In order to determine the effect of hyster-
esis on the suction distribution in the monolith, calculations were performed
either with the desorption curve or with the sorption curve without scanning
between the curves. Neither of the two curves led to complete agreement between
observed and calculated soil suction values; the desorption curve usually gave
too high values, and the sorption curve gave too low values.
76:020-004
RADIATION HAZARD FROM AMERICIUM-BERYLLIUM NEUTRON MOISTURE PROBES.
Gee, G.E., Stiver, J.F., and Borchert, H.R.
North Dakota State University, Department of Soils, Fargo, North Dakota.
Soil Science Society of America Journal, Vol. 40, No. 4, p 492-494, July-August
1976. 3 fig, 1 tab, 4 ref.
Descriptors: *Soil moisture meters, *Nuclear moisture meters, *Hazards, *Radia-
tion, Soil moisture, Radioactivity, Safety, Instrumentation, Equipment, Monitor-
ing, Measurement, Soil science.
Neutron fluxes from shielded neutron moisture probes need to be measured to
evaluate total radiation exposure from these instruments. Theoretical consider-
ations suggest that for 100 mCi Am-Be neutron moisture probes the fast neutron
flux can be relatively high and contribute significantly to the radiation expo-
sure of probe operators. Measured radiation dose levels at the surface of 100
mCi Am-Be newtron probes manufactured by Troxler Laboratories were found to be
as high as 37 m Rem/hour which exceeds reported levels by as much as 38 times.
This was believed to be due to nonreporting of fast neutron fluxes. It was
mentioned that conventional field use of these probes may present a radiation
hazard to operators if the probe is hand carried for periods which exceed three
hours per week. It was recommended that the probe be transported to and from
sites inside a wooden storage crate and be kept at least 1 m from personnel.
Also, to improve the radiation safety factor for on site use, it was recommended
that a hand cart be used to transport the probe.
76:020-005
MEASURING HYDROLOGIC PROPERTIES OF SOIL WITH A DOUBLE-RING INFILTROMETER AND
MULTIPLE-DEPTH TENSIOMETERS,
Ahuja, L.R., El-Swaify, S.A., and Rahman, A.
Hawaii University, Department of Agronomy and Soil Science, Honolulu, Hawaii.
Soil Science Society of America Journal, Vol. 40, No. 4, p 494-499, July-August
1976. 10 fig, 1 tab. 5 ref.
Descriptors: *Hydrologic properties, *Soil water movement, *Soil physical prop-
erties, *Hawaii, Soil properties, * Infiltration, *Infiltrometers, *Tensiometers,
On-site investigations. Forests, Forest watersheds, Soils, Loam, Clay loam, Per-
colation, Groundwater movement. Water spreading, Soil science, Instrumentation.
A ring infiltrometer with varying width of buffer zone in combination with mul-
tiple-depth tensiometers was tested for determining the hydrologic properties
of a Typic Dystrandept (Tantalus silty clay loam) soil profile on a forested
watershed in Hawaii. With location of one multiple-depth tensiometer at the
vertical axis of theaxisymmetric flow system and one or more at a given radius
outside-the inner ring, the vertical and the radial hydraulic gradients could
be simultaneously measured. It was thus possible to estimate the lateral flow
components and to determine vertical infiltration rates and hydraulic conduct-
ivities (at field saturation) of the different soil horizons. Lateral flow
decreased with time during infiltration. Under the moist-to-wet conditions of
35
-------
the soil under study, lateral flow was not appreciable. From an inner ring of
30-cm diameter, the lateral flow was practically eliminated when a buffer ring
of 90-cm diameter was employed. The effect of lateral flow on the final infil-
tration rate was negligible even when a buffer ring of 60-cm diameter was used.
76:02G-006
VISCOSITY OF INTERLAYER WATER IN MONTMORILLONITE,
Low, P.F.
Purdue University, Department of Agronomy, Lafayette, Indiana.
Soil Science Society of America Journal, Vol. 40, No. 4, p 500-505, July-August
1976. 4 fig, 1 tab, 30 ref.
Descriptors: *Viscosity, *Permeability, *Clays, *Montmorillonite, *Viscous flow,
Flow resistance. Diffusion, Hydraulic conductivity, Porous media, Soils, Soil
properties. Physical properties, Analytical techniques, Groundwater movement,
Soil science.
The viscosities of water in Na-montmorillonite system at various contents were
calculated by different equations using data from experiments conducted by
different investigators on; (1) viscous flow of water at different temperatures,
(2) self-diffusion of water, and (3) neutron scattering by water. The results
were remarkably consistent and showed that the viscosity of the interlayer water
is greater than that of bulk water and increases exponentially with decreasing
water content. Evidence was also presented to show that the viscosity of this
water depends on the b-dimension of the montmorillonite. By combining the data
on viscosity with data on hydraulic conductivity, it was possible to determine
the permeability of the montmorillonite at different water contents.
76:020-007
HEAT AND WATER MOVEMENT UNDER SURFACE ROCKS IN A FIELD SOIL: I. THERMAL EFFECTS,
Jury, W.A., and Bellantouni, B.
California University, Department of Soil Science and Agricultural Engineering.
Soil Science Society of America Journal, Vol. 40, No. 4, p 505-509, July-August
1976. 6 fig, 2 tab, 13 ref.
Descriptors: *Soils, *Rocks, *Heat flow, *Soil moisture, Soil water movement,
On-site investigations, Model studies. Mathematical models, Thermal conductivity,
Water vapor, Mulching, Droughts, Arid lands, Groundwater movement, Soil science.
Results of a field experiment designed to evaluate the effect of surface rocks
on soil heat flow were presented. Temperature observations were made by thermo-
couples at 12 locations under and adjacent to rocks placed over bare soil. Con-
tinuous readings were taken for 24- and 48-hour intervals using seven different
kinds of rock cover, ranging from large granite slabs to gravel piles, during
the time between December 1974 and August 1975. Experimental results consis-
tently showed a non-negligible 24-hour net horizontal heat flow toward the rock
at both the 2.5 and 5.0 cm depth. Net vertical heat flow was always downward
in the soil under the bare surface but was observed to be either upward or down-
ward in the soil under the rock cover depending on prior conditions. Because
water vapor movement in moist soil is generally in the same direction as heat
flow, it was suggested that surface rock cover may be a mechanism for water
collection in arid climates. A simulation model was constructed to describe
two-dimensional heat flow in a uniform soil with a rectangular rock on the
surface. Using the measured surface temperature as boundary values and a soil
thermal conductivity corresponding to the mean daily soil surface temperature,
the simulation model adequately reproduced the observed temperatures under and
adjacent to the rock.
76:020-008
HEAT AND WATER MOVEMENT UNDER SURFACE ROCKS IN A FIELD SOIL: II. MOISTURE
EFFECTS,
Jury, W.A., and Bellantouni, B.
California University, Department of Soil Science and Agricultural Engineering,
Riverside, California.
Soil Science Society of America Journal, Vol. 40, No. 4, p 509-513, July-August
36
-------
1976. 5 fig, 3 tab, 7 ref.
Descriptors: *Soils, *Rocks, *Heat flow, *Soil moisture. Soil water movement,
On-site investigations, Laboratory tests, Model studies, Mathematical models,
Computer models, Thermal conductivity, Water vapor, Mulching, Droughts, Arid
lands, Groundwater movement, Moisture effects.
Results were presented from a field experiment conducted to determine the effect
of surface rocks on soil water content change under bare soil. First, stones
were placed at intervals over an initially dry field (gravimetric water content
= 0.021 g/g) and left for 6 weeks. Subsequent sampling showed a small, but
detectable, excess of water stored under the rock compared to adjacent bare
soil. Following an irrigation, buried thermal conductivity probes were used to
monitor water content changes under and adjacent to surface rocks. After 24
days, the soil under the rock contained significantly more water than did the
soil region adjacent to the rock, a finding confirmed by gravimetric sampling.
Following this, the stones and probes were relocated for a further 24 days of
observation, with similar results obtained. In a separate laboratory experi-
ment using a large, sealed soil column with a rock covering part of the surface,
it was demonstrated that a significant amount of water moved to the cylinder of
soil under the rock from the soil region under the bare surface due to horizontal
temperature gradients induced by the rock covering part of the surface. A two-
dimensional computer program calculating water vapor movement under thermal
gradients was used with measured field temperature boundary conditions to esti-
mate the amount of water vapor movement expected to occur due to a rock cover
on the soil surface. Results qualitatively confirmed the observations of the
sealed laboratory column experiment.
76:02G-009
FIELD MAPPING SOIL CONDUCTIVITY TO DELINEATE DRYLAND SALINE SEEPS WITH FOUR-
ELECTRODE TECHNIQUE,
halvorson, A.D., and Rhoades, J.D.
Agricultural Research Service, Sidney, Montana.
Soil Science Society of America Journal, Vol. 40, No. 4, p 571-575, July-August
1976. 7 fig, 3 tab, 8 ref.
Descriptors: *Saline soils, *Conductivity, *0n-site investigations. Arid lands,
Salinity, Measurement, Salts, Groundwater, Seepage, Mapping, Soil water. Soils,
Maps, Surveys, Soil science.
Continuing incidence of saline-seep areas in the northern Great Plains dryland
soils has created a need for detecting and delineating encroaching saline seeps
before plant growth is affected. This paper reported on an evaluation of the
four-electrode conductivity technique for field mapping surface and subsurface
soil salinity under dryland conditions. Results indicated that the four-elec-
trode conductivity technique can be used successfully to quickly field map sur-
face and subsurface soil salinity boundaries of existing and potential saline-
seep areas. This technique also depicted underground flow patterns of a shallow,
saline groundwater table. Maps of apparent bulk soil conductivity values were
used to locate the position of the recharge area in relation to the discharge
(seep) area. While maps of discrete depth interval conductivity values provi-
ded more precise information, the time required may not warrant the additional
required calculations unless a portable programmable calculator is available.
Mapping soil salinity with the four-electrode conductivity technique was easy,
rapid, and relatively inexpensive. This technique provides information useful
in making management decisions to prevent or alleviate a saline seep or other
soil salinity problems.
76:02G-010
A MARKOVIAN STOCHASTIC BASIS FOR THE TRANSPORT OF WATER THROUGH UNSATURATED SOIL,
Bhattacharya, R., Gupta, V., and Sposito, G.
Arizona University, Department of Mathematics, Tucson, Arizona.
Soil Science Society of America Journal, Vol. 40, No. 3, May-June 1976b. 11 ref.
OWRT B-046-ARIZS5). 14-34-0001-6057.
Descriptors: *Hydraulic conductivity, *Markov processes, *Unsaturated flow,
Stochastic processes, Equations, *Soil water movement, Diffusivity, Soil moisture.
37
-------
The differential equation that describes the isothermal, isohaline transport of
water through a homogeneous, isotropic, unsaturated soil is shown to result from
a fundamental stochastic hypothesis; that the trajectory of a water molecule is
a non-homogenous Markov process characterized by space- and time-dependent coef-
ficients of drift and diffusion. The demonstration makes possible a new theoret-
ical interpretation of the water diffusivity and the hydraulic conductivity at
the molecular level and results in a derivation to the Buckingham-Darcy flux
law that does not rely directly on experiment.
76:02G-011
COMPARISON OF DRAINAGE EQUATIONS FOR THE GRAVITY DRAINAGE OF STRATIFIED PROFILES,
Watson, K.K., and Whisler, F.D.
Mississippi State University, Department of Agronomy, Mississippi State, Miss-
issippi.
Soil Science Society of America Journal, Vol. 40, No. 5, p 631-635, September-
October 1976. 3 fig, 3 tab, 10 ref.
Descriptors: *Drainage, *Gravity, *Percolation, *Equations, Numerical analysis.
Model studies, Mathematical models, Unsaturated flow. Soil water, Soils, Compu-
ters, Profiles, Sands, Analytical techniques, Soil science, Agriculture.
The output from a computer-based numerical analysis of the gravity drainage of
a sand profile through an underlying impeding layer was used as the data for
testing the manner in which algebraic equations are capable of describing the
stratified drainage process. The comparisons indicated that no single equation
is satisfactory in describing the wide range of nonlinear behavior that occurred
with eight cases analyzed. However, when specific coefficients determined from
a least squares analysis were used in an equation of the Jackson and Whisler
type, satisfactory correspondence was achieved.
76-.02G-012
EFFECTS OF LIQUID-PHASE ELECTRICAL CONDUCTIVITY, WATER CONTENT, AND SURFACE
CONDUCTIVITY ON BULK SOIL ELECTRICAL CONDUCTIVITY,
Rhoades, J.D., Raats, P.A.C., and Prather, R.J.
Agricultural Research Service, Salinity Laboratory, Riverside, California.
Soil Science Society of America Journal, Vol. 40, No. 5, p 651-655, September-
October 1976. 7 fig, 3 tab, 13 ref.
Descriptors: *Electrical conductivity, *Soils, *Soil water, Model studies,
Laboratory tests. Mathematical models, Salinity, Saline soils, Soil properties,
Soil types, Soil science.
Recent research has demonstrated that field soil salinity can be inferred from
four-electrode soil electrical conductivity if the soil profile is near 'field
capacity1 and calibration curves, based on saturation extract salinity, are
available. To extend the use of this field method to arbitrary water contents,
electrical conductivity was studied in the laboratory as a function of water
content and in situ soil water conductivity. Undisturbed cores of four soil
types were collected using Lucite column inserts, which were tapped for later
insertion of electrodes. The cells were equilibrated with waters of a desired
conductivity and, using a pressure membrane apparatus, adjusted to a desired
water content. Values of soil electrical conductivity were calculated from
measured four-electrode resistances and an appropriate cell constant. A rela-
tionship was derived using a simple capillary model, which assumes that liquid
phase and surface conductivities (via exchangeable cations) behave as resistors
in parallel.
76:02G-013
SURFACE SOIL MOISTURE WITHIN A WATERSHED—VARIATIONS, FACTORS INFLUENCING, AND
RELATIONSHIP TO SURFACE RUNOFF,
Henninger, D.L., Petersen, G.W., and Engman, E.T.
Pennsylvania State University, University Park, Pennsylvania.
Soil Science Society to America Journal, Vol. 40, No. 5, p 773-776, September-
October 1976. 2 fig, 4 tab, 16 ref.
Descriptors: *Soil moisture, *Watersheds (Basins), *Pennsylvania, Surveys, Data
38
-------
processing,, Soils, Soil types, Precipitation (Atmospheric), Runoff, Evaporation,
Vegetation effects, Drainage, Moisture meters, Nuclear moisture meters, Soil
science.
Surface soil moisture was measured within the upper 15 cm, using neutron-scat-
tering equipment, on six soil series, within a 57.8-ha Pennsylvania watershed
during the 19 May to 11 November 1971 period. Surface soil moisture was respon-
sive to individual storm events, showed discernible seasonal trends, and dis-
played larger fluctuations at higher moisture levels than at lower moisture
levels. An analysis of variance showed that well-drained soils had significantly
different surface soil moisture levels than the more poorly drained soils. Also,
yell-drained soils could be grouped into a hydrologic unit distinct from the
more surements along parallel transects which were approximately perpendicular
to the slope contours, showed high surface soil moisture contents proximal to
the stream, indicating that these areas contribute more to surface runoff in a
shorter period of time than areas distant from the stream channel. Multiple
regression equations, using pan evaporation and surface soil moisture for each
soil series, were used to show the relative importance of the internal soil
drainage class in predicting surface runoff.
76:02G-014
PREDICTING RUNOFF INITIATION TIMES UNDER FIELD CONDITIONS IN TROPICAL (HAWAII)
SOILS,
Ahuja, L.R., Dangler, E.W., and El-Swaify, S.A.
Hawaii Universtiy, Department of Agronomy and Soil Science, Honolulu, Hawaii.
Soil Science Society of America Journal, Vol. 40, No. 5, p 777-779, September-
October 1976. 1 fig, 1 tab, 10 ref. ARS-USDA 12-14-5001-19, 12-14-5001-40.
Descriptors: *Runoff, *Soil types, *Hawaii, *Simulated rainfall. Rainfall-
runoff relationships, Soils, Infiltration, Ponding, Rainfall, Precipitation
(Atmospheric), Surface runoff. Hydraulic conductivity-
Runoff initiation times measured during field rain-simulation studies on 10
important Hawaii soils were examined in relation to antecedent soil water status.
The experimental data showed considerable scatter, which was due mainly to
natural soil variability within a soil series. However, the data exhibited a
fairly proportional relationship between runoff initiation time and antecedent
soil saturation deficit (final minus initial soil water content), in accordance
with a simple Green-Ampt type equation. The results indicated a potential
method for estimating erosive portions of rainstorms and subsequent soil loss
hazards in relation to varying antecedent soil water contents during different
seasons of the year.
76:02G-015
AN ELECTRICAL CONDUCTIVITY PROBE FOR DETERMINING SOIL SALINITY,
Rhoades, J.D., and van Shilfgaarde, J.
Agricultural Research Service, Salinity Laboratory, Riverside, California.
Soil Science Society of America Journal, Vol 40, No. 5, p 647-651, September-
October 1976. 4 fig, 2 tab, 7 ref.
Descriptors: *Saline soils, *Electrical conductance, *Instrumentation, *Equip-
ment, Soil properties, Irrigation, Salts, Electrical equipment, Soils, Salinity,
Soil Science, *Salinity.
An electrical conductivity probe for determining soil salinity was described,
including construction details. The probe's utility for measuring soil salinity
within discrete soil depth intervals was illustrated with examples. Using the
salinity probe, the Barnes method for estimating electrical conductivity profiles
was shown to be accurate for soils that are reasonably homogeneous laterally.
76:026-016
PREDICTION OF EVAPORATION FROM COLUMNS OF SOIL DURING ALTERNATE PERIODS OF
WETTING AND DRYING,
Staple, W.J. . _ ,
Soil Research Institute, Department of Agriculture, Ottawa, Ontarxo, Canada.
Soil Science Society of America Journal, Vol. 40, No. 5, p 756-761, September-
39
-------
October 1976. 7 fig, 1 tab, 22 ref.
Descriptors: *Evaporation, *Soils, *Soil properties, Infiltration, Laboratory
tests, Model studies, Hydraulic conductivity, Drying, Wetting, Soil moisture,
Soil water movement, Loam, Soil water, Soil science.
The analysis was undertaken to test certain approximations in using finite dif-
ference methods to compute evaporation and soil water conservation. Analysis of
four evaporation experiments showed that water movement in Wood Mountain ciay
loam was sufficiently repeatable during wetting and drying to permit computation
of evaporation losses on the basis of predetermined soil properties The exper-
iments involved evaporation after the following treatments: (1) infiltration
penetrating partway down columns of air-dry soil; (2) infiltration and 7 days
redistribution; (3) treatment (2) plus additional infiltration; and (4) repeated
infiltration applied at different stages of initial drying. In computing evap-
oration, the Richards and Dalton flow equations were used with soil and atmos-
pheric parameters. Temperature gradients in the soil were neglected. Hydraulic
conductivity of the surface layers of soil were adjusted empirically to estimate
combined liquid and vapor movement and to correct for disruptive effects such
as dispersion, air blockage, and swelling near the surface. The independent
domain theory was used to estimate the influence of hysteresis on capillary
pressures during alternate wetting and drying. Agreement between measured and
computed evaporation was satisfactory following infiltration, except when water
was added after more than 7 days' evaporation.
76:020-017
SEEPAGE FROM TRAPEZOIDAL CANAL IN ANISOTROPIC SOIL,
Reddy, A.S., and Basu, U.
Indian Institute of Science, Department of Civil Engineering, Bangalore.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 102, No. IR2, Proceedings Paper 12386, p 349-361, September
1976. 6 fig, 28 ref. 2 append.
Descriptors: *Irrigation, *Seepage, *Canals, Irrigation canal, Permeability,
Anisotropy, Homogeneity, Phreatic lines, Hydrology, Hudraulics, Equations,
Flow.
An analytical solution which takes into account the general anisotropic behavior
of the porous medium was found for the problem of seepage flow from an unlined
trapezoidal canal. Since a canal in an anisotropic medium transforms into one
with unequal slopes in an equivalent isotropic porous medium, the solution here
was concerned with the problem of seepage flow from an unsymmetrical trapezoidal
canal. The method of inversion of hodograph was made use of, and expressions for
the seepage loss and the locations of the phreatic lines were obtained. Numeri-
cal results were presented for the equivalent isotropic flow domain. Using the
transformation formulas given, the actual discharge and the locations of phreatic
lines in anisotropic medium can be easily obtained for given physical parameters
of the actual flow domain. The nonsymmetry of trapezoidal canals of side slopes
less than one has considerable influence on the quantity of seepage.
76:02G-018
PREDICTION OF INFILTRATION INTO LAYERED FIELD SOILS IN RELATION TO PROFILE
CHARACTERISTICS,
Bruce, R.R., Thomas, A.W., and Whisler, F.D.
Agricultural Research Service, Watkinsville, Georgia.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 4,
p 693-698, 703, July-August 1976. 12 fig, 4 tab, 15 ref.
Descriptors: *Infiltration, *Soil profiles, *Soil classification, *Storms,
*Soil horizons, *Pressure head. Soil moisture, Hydraulics, Porosity, Numerical
analysis, Soil physics, On-site tests, *Forecasting.
An infiltration model based on flow theory was used to examine the effects of
nature and extent of soil horizons in profiles of a clayey soil upon infiltratjbn
and soil water distribution. It was concluded that the characteristics and
thickness of the surface soil horizon which overlies a subsoil of higher clay
content and lower saturated hydraulic conductivity determine infiltration and
40
-------
consequent distribution fo soil water during a significant period of a rainfall
event. The period may vary from 10 to 40 minutes for high-intensity storms,
depending upon initial soil water content, and for a longer period for dry soils
and low-intensity storms. The B2 horizon of the soil tested begins to regulate
infiltration after 30 to 40 minutes. The duration of these periods assumes
insignificant effect hydraulic characteristics. The model adequately described
infiltration into a grass covered plot.
76:02G-019
ANALYTICAL SOLUTIONS OF A SIMPLIFIED FLOW EQUATION,
Raats, P.A.C.
Agricultural Research Service, Salinity Laboratory, Riverside, California.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 4,
p 683-689, July-August 1976. 6 fig, 35 ref.
Descriptors: *Infiltration, *Soil water movement, *Hydraulic conductivity,
*Moisture content, *Analytical techniques, Pressure head, Hydraulics, Soil
physics. Model studies, Flow, Capillary action, Equations.
Assuming that the hydraulic conductivity is an exponential function of the
pressure head, a simplified flow equation was derived. The influence of
hysteresis was ignored. The flow equation contained a constant that can be
interpreted as a natural length of the soil and a function that delimits a
natural time. Solutions of three special forms of the flow equation were dis-
cussed: (1) steady flows from point and line sources and to points and line
sinks, (2) steady vertical flow, subject to distributed uptake by plant roots
and a water table, and (3) transient redistribution following irrigation. All
solutions presented hinge upon the exponential and the pressure head. The
relationship was believed to be valid if the range of hydraulic conductivities
is small.
76:02G-020
EFFECT OF MICROORGANISMS ON THE SORPTION AND FATE OF SULFUR DIOXIDE AND NITROGEN
DIOXIDE IN SOIL,
Ghiorse, W.C. , and Alexander,- M.
Cornell University, Department of Agronomy, Ithaca, New York.
Journal of Environmental Quality, Vol. 5, No. 3, p 227-230, July-September 1976.
3 fig, 4 tab, 22 ref.
Descriptors: *Sorption, *Nitrification, *Microorganisms, Sulfur compounds.
Sulfur dioxide was rapidly removed from the gas phase in contact with both
nonsterlle and sterile soil so that viable microorganisms are not directly
involved in removal of this pollutant from the atmosphere. Sulfate was formed
from the S02 in nonsterile and sterile soil. About one-fourth of the sulfur
from the SO2 introduced was not recovered in inorganic form, but the recovery
was quantitative if the soil was first ignited to destroy organic matter.
Nitrogen dioxide was also readily lost f'rom the gas phase in contact with non-
sterile and sterile soil, and both nitrite and nitrate were generated. The
role of microorganisms in the fate of this pollutant is in the conversion of
the nitrite to nitrate.
76:020-021
EFFECT OF DISSOLVED OXYGEN ON REDOX POTENTIAL AND NITRATE REMOVAL IN FLOODED
SWAMP,
Engler, R.M., Antie, D.A., and Patrick, W.H. Jr.
Department of the Army, Corps of Engineers, Waterways Experiment Station,
Environmental Effects Laboratory, Vicksburg, Mississippi.
Journal of Environmental Quality, Vol. 5, No. 3, p 230-235, July-September 1976.
6 fig, 2 tab, 14 ref.
Descriptors: *Nitrates, *Dissolved oxygen, *Louisiana, *Floodwater, Coastal
marshes, Laboratory tests. Soil investigations.
The O2 depletion rates, N03(-) loss, and the effects of added 02 on N03(-)
41
-------
disappearance and redox potential in four flooded or intermittently flooded
soils from the swamp and coastal marshes of Louisiana were quantitatively char-
acterized in a laboratory study. The N03(-) added either to the shallow flood-
water or mixed with the soil in a suspension rapidly disappeared. Eighty to
ninety parts per million N03{-) was lost from the soil suspensions in 1 to 4
days and from the floodwater over a soil in 10 to 20 days. No N03(-) was lost
from floodwater separated from the soils. Oxygen depletion in the soil suspen-
sions occurred in 15 minutes to 4 hours. Redox potential curves exhibited a
characteristic inflection after 02 disappearance in all soils studied. Nitrate
disappearance did not appear to be inhibited by as much as 16 ppm O2 dissolved
in the soil suspensions because the 02 was rapidly consumed.
76:02G-022
THE EFFECTS OF TEMPERATURE AND SOIL WATER ON CONVERSION OF DDT TO DDE IN SOIL,
Guenzi, W.D., and Beard, W.E.
United States Department of Agriculture, Agricultural Research Service, Western
Region, P.O. Box E., Fort Collins, Colorado.
Journal of Environmental'Quality, Vol. 5, No. 3, p 243-246, July-September 1976.
2 fig, 2 tab, 13 ref.
Descriptors: *Pesticides, *Insecticides, *Chemical degradation, *Persistence,
*Microbial degradation, Soil water, Soil investigations, Temperature.
A laboratory study was conducted to determine the rates of DDT degradation
and DDE formation in soil. Degradation rates increased with higher temperatures
and in the presence of water. Of the DDT mixed with Raber silty clay loam, 82.1,
74.5, 53.2, and 38.3% was recovered as DDT and 6.7, 12.5, 21.6, and 34.8% as
DDE after 140 days incubation at 30, 40, 50, and 60C, respectively. A compar-
ison of DDE formation in sterile and nonsterile soil showed that 84% of the
conversion was due to a chemical process at 30C, and 91% at 60C. In sterile
systems at 30C, rates of DDE formation were similar in submerged soil and soil
at 1/3 bar suction, and both were much higher than in air-dried soil.
76:020-023
INFLUENCE OF CROP MANAGEMENT PRACTICES ON NUTRIENT MOVEMENT BELOW THE ROOT ZONE
IN NEBRASKA SOILS,
Muir, J., Boyce, J.S., Seim, E.G., Mosher, P.N., and Deibert, E.J.
Nebraska Agricultural Experiment Station, Lincoln, Nebraska.
Journal of Environmental Quality, Vol. 5, No. 3, p 255-259, July-September, 1976.
9 fig, 12 ref.
Descriptors: *Nitrogen, *Potassium, *Root zone, *Leaching, Irrigation effects,
Nebraska, Soil investigations. Alfalfa, Corn.
Deep profile sampling under different water and crop management systems revealed
limited movement of N and none of P from the rooting profile of non irrigated
Nebraska soils. Leaching of N to the water table was apparent in most irrigated
soils located on valley positions and in sandy soils of the uplands. Alfalfa
with its deep rooting system, was noted to be an effective scavenger of inorganic
N that may have accumulated under prior crops.
76:02G-024
EVALUATION OF A CAPILLARY BUNDLE MODEL FOR DESCRIBING SOLUTE DISPERSION IN
AGGREGATED SOILS,
Rao, R.S.C., Green, R.E., Ahuja, L.R., and Davidson, J.M.
Florida University, Department of Soil Science, Gainesville, Florida.
Soil Science Society of America Journal, Vol. 40, No. 6, p 815-820, November-
December 1976. 4 fig, 2 tab, 21 ref.
Descriptors: Model studies, Hawaii, Soil water. Soil water movement, Pores,
Pore water, Soils, Soil investigations.
A simple capillary bundle model was evaluated for describing solute dispersion
in two well-aggregated soils of Hawaii. The model enables the use of pore-
water velocity distribution rather than an average pore-water velocity. The
pore-size distribution was calculated from the soil water characteristic data.
42
-------
The position and relative shape of the break-through curves calculated by the
capillary bundle model was dependent more on the pore-water velocity distribu-
tion than on dispersion owing to mixing within a pore. The predicted break-
through curves were extremely skewed and did not describe the measured curves.
The mixing of solute between adjacent flow paths, a process not accounted for in
the model, apparently resulted in failure of the model. A measure of pore
accessibility and interconnectedness of pore sequences is essential for quanti-
tative description of the influence of soil pore geometry on solute dispersion.
76:02G-025
SIMULATION OF PROFILE WATER STORAGE AS RELATED TO SOIL HYDRAULIC PROPERTIES,
Hillel, D., and Van Bavel, C.H.M.
Texas A and M University, Texas Agricultural Experiment Station, Department of
Soil and Crop Science, College Station, Texas.
Soil Science Society of America Journal, Vol. 40, No. 6, p 807-815, November-
December 1976. 12 fig, 1 tab, 18 ref.
Descriptors: Numerical analysis. Simulation analysis. Soil properties, Soil
investigations, Model studies, Soil moisture, Soil water,- Soil water movement,
Infiltration, Water conservation, Evaporation.
A previously published numerical model of soil-water dynamics was used to simu-
late the separate and combined processes of infiltration, drainage, and evapora-
tion, as determined by hydraulic properties. Three hypothetical soils were
compared: sand, loam, and clay. Typical soil moisture characteristic functions
were assigned to each, and the respective hydraulic conductivity functions were
calculated. Uniform profiles of these soils were then subjected to various
sequences of rainstorms and dry periods. The sandy soil provided the least
evaporation and the most rapid downward flow. This resulted in the most effec-
tive storage under a relatively dry regime. The situation was reversed in the
case of the clay soil, which stored the most water under a relatively wet
regime, while the loam exhibited intermediate behavior. Some consequences
of this pattern affecting arid zone ecology are discussed.
76:020-026
EXPERIMENTAL STUDY OF WETTING FRONT INSTABILITY INDUCED BY SUDDEN CHANGE OF
PRESSURE GRADIENT-
White, I., Colombera, P.M., and Philip, J.R.
Commonwealth Scientific and Industrial Research Organization, Division of
Environmental Mechanics, P.O. Box 821, Canberra City, 2601 Australian Capital
Territory, Australia.
Soil Science Society of America Journal, Vol. 40, No. 6, p 824-829, November-
December 1976. 8 fig, 2 tab, 10 ref.
Descriptors: *Soil water. Soil water movement, Infiltration, Soil investiga-
tions, Soil properties. Soil moisture.
Twenty-two experiments were performed on stability of infiltration flows in
Hele-Shaw cells. Flows were perturbed by suddenly changing G, the pressure
gradient behind the wetting -front, from a definite negative to a definite
positive value. Three methods were used; (i) increasing air-pressure ahead of
the front, (ii) employing a nonwetting stratum, and (iii) suddenly stopping
liquid supply and preventing air-entry. Glycerol and silicone, with contrasting
properties, were used as the infiltrating liquids. The experiments confirmed
the theory of Philip: immediately G was made positive, all flows became
unstable, and the observed wavelengths of fingering agreed closely with
those predicted by the theory. A modification of the theory to take account
of the geometry of the microscopic air-liquid interface predicts wavelengths
in soil about twice as large as does the original theory. A preliminary exper-
iment on infiltration of water in a coarse sand confirmed the theory qualita-
tively, but the observed wavelength was twice that predicted theoretically. In
a preliminary experiment on infiltration in a fine sand, perturbation failed to
produce instability. This divergence from theory is attributed to deviations
from the delta-function model on which the theory is based. Further experimen-
tal and theoretical work is needed.
43
-------
76.-02G-027
EFFECT OF PH AND COMPLEX FORMATION ON MERCURY (II) ADSORPTION BY BENTONITE,
Newton, D.W., Ellis, R. Jr., and Paulsen, G.M.
Kansas State University, Department of Agronomy, Manhattan, Kansas.
Journal of Environmental Quality, Vol. 5, No. 3, p 251-254, July-September 1976.
3 fig, 3 tab, 14 ref.
Descriptors: *Heavy metals, *Clays, *Chlorides, *Salts, *Mercury, Aquatic
environment, Aquatic population.
Reactions of Hg with bentonite clay were studied to determine behavior of the
metal in aquatic ecosystems. Mercury (II) adsorption by bentonite as a function
of pH and complex formation was investigated using a radioisotopic technique.
Maximum Hg(II) adsorption in 0.01M Ca(N03)2 systems occurred in the pH range
4.5-5.5. Varying the Ca(NO3)2 concentration only slightly influenced adsorption
or the pH of maximum adsorption. Chloride ions sharply reduced Hg(II) adsorp-
tion, especially at low pH's. At pH 6 or lower.- increasing CaC12 levels were
required to decrease adsorption at pH 7. At a given Cl(-) concentration,
maximum observed Hg(II) adsorption occurred near the calculated pH where HgClOH
occurred as a transition complex between HgC12 and Hg(OH)2. Chloride salts
were more effective desorbers of Hg(II) than was 0.01M Ca(N03)2 or various o.OlN
acids. HCL (O.OlN) removed the most adsorbed Hg(II).
76:02G-028
SIMULATION OF ROOT-ZONE WATER AND DEEP SEEPAGE TO A WATER TABLE,
King, T.G., and Lambert, J.R.
Connell/Metcalf and Eddy, Coral Gables, Florida.
Presented at the 1975 Winter Meeting of the American Society of Agricultural
Engineers, December 15-18, 1975, Chicago, Illinois. 12 p., 5 fig, 2 ref.
Descriptors: *Model studies, *Root zone. Moisture tension, Soil water, *Soil
water movement, *Seepage, *Water table, Evapotranspiration, *Computer models,
Simulation analysis.
The primary objective was to develop a computer model that would simulate the
quantity and movement of water in the deep seepage region, i.e., between the
root zone and the water table. Effort was also directed towards simulating
evapotranspiration and the movement of the water table. The model has been
structured so that it may readily be modified to other locations where basic
meteorological records and soil data are available.
76:02G-029
MODELING INFILTRATION AND REDISTRIBUTION OF SOIL WATER DURING INTERMITTENT
APPLICATION,
James, L.G., and Larson, C.L.
Minnesota University, Department of Agricultural Engineering, St. Paul,
Minnesota.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 482-488, May-June 1976. 7 fig, 4 tab,22 ref.
Descriptors: *Infiltration, *Infiltration rates, *Soil physics, *Unsaturated
flow, *Soil water movement, *Unsteady flow, Soils, Porous media, Equations,
Soil properties, Mathematical models, Laboratory tests, Computers.
A model that used relatively simple and reasonably accurately measured parameter
equations was used to represent infiltration and redistribution of soil water
during intermittent water applications. Application of the model was limited
to short time periods since evapotranspiration was neglected and only impervious
and air-soil interface type lower boundaries to the soil zone were considered.
The soil was required to be homogeneous and to have distinct wetting front.
Laboratory data were collected and compared with the model predictions. The
model was found to predict satisfactorily the runoff quantities and timing, the
volume of water stored in the soil, and the soil moisture profiles including
the position of the wetting front. The model over-predicted the infiltration
rate when the application rate exceeded tht infiltration capacity of the soil.
44
-------
76:02G-030
RAPID DETERMINATION OF UNSATURATED HYDRAULIC CONDUCTIVITY IN TILLED AND UNTILLED
LOESS SOIL,
Ehlers, w.
Gottingen University, Institut fur Pflanzenbau und Pflanzenzuctung, von-Siebold-
Str. 8, 34 Gottingen, West Germany.
Soil Science Society of America Journal, Vol. 40, No. 6, p 837-840, November-
December 1976. 3 fig, 4 tab, 12 ref.
Descriptors: *Hydiraulic conductivity, *Diffusivity, Evaporation, Porosity,
Soil properties, Soil investigations.
A rapid method recently developed for determining moisture diffusivity and
unsaturated hydraulic conductivity in undisturbed soil cores was employed to
calculate the hydraulic functions of the upper layers of tilled and untilled
loess soil. The results obtained with the new method compare well with results
obtained by a field method. Diffusivity functions as influenced by tillage and
depth were significantly different. Conductivities were highest in the 20-30-cm
layer of untilled and were lowest in the same layer of tilled soil. The number
of replicates necessary to evaluate the hydraulic functions with arbitrarily
specified precision was calculated. For the soil under study, five to nine
samples are needed, when upper and lower limits of the 95% confidence interval
of diffusivity means are defined not to be different more than by a factor of
three.
76:02G-031
POTASSIUM STATUS OF SOME ALLUVIAL SOILS IN KENTUCKY,
Rasnake, M., and Thomas, G.W.
Kentucky University, Department Of Agronomy, Lexington, Kentucky.
Soil Science Society of America Journal, Vol. 40, No. 6, p 883-886, November-
December 1976. 7 fig, 3 tab, 21 ref.
Descriptors: *Kentucky, *Potassium, *Bermudagrass, Soil chemistry. Soil chemical
properties, Soils, Soil investigations.
Six alluvial soils from Kentucky were intensively cropped to 'Midland' bermuda-
grass to determine K availabiltiy in each soil. Potassium removal by the berm-
udagrass was compared to exchangeable K, to labile K estimated from Beckett
quantity/intensity plots and to Gapon coefficients before and after cropping.
Exchangeable K was not a good measure of uptake (r = 0.61 not significant), but
labile K determined on soils before cropping and the Gapon coefficient after
cropping gave highly significant linear correlations with K removed by bermuda-
grass. Exchangeable K after cropping changed an average of only 23 ppm K in
the soils, but availability of K to plants was lowered drastically in all soils.
This study shows that exchangeable K is an insensitive measurement of K availa-
bility to plants. Exchangeable K is a useable measurement only because wide
ranges are used in determining classes of availability in soil testing.
76:02G-032
COUPLING PHENOMENA IN SATURATED HOMO-IONIC MONTMORILLONITE: II. THEORETICAL,
Groenevelt, P.H., and Elrick, D.E.
Guelph University, Department of Land Resource Science, Guelph, Ontario, Canada.
Soil Science Society of America Journal, Vol. 40, No. 6, p 820-823, November-
December 1976. 11 ref.
Descriptors: *Clays, Soil water. Soil water movement, Model studies, Thermo-
dynamics, Salts, Saturated soils.
A theory is presented for the formulation of flux equations which describe the
transport of water.- salt, and electric charge through clays. This theory is
based on thermodynamics principles. Model considerations lead to analytical
expressions for the transport coefficients. These model calculations are based
on electric double layer theory and produce a symmetric matrix of coefficients.
The difference with former theories and model calculations is that the analysis
is for electrodes which are reversible to the anions instead of the cations.
The impact of this difference on the magnitude of some of the coefficients and
45
-------
on some of the physico-chemical responses of the system is formidable.
76:02G-033
AN IMPROVED TECHNIQUE FOR MEASURING SOIL PH,
Mubarak, A., and Olsen, R.A.
Montana State University, Agricultural Experiment Station, Bozeman, Montana.
Soil Science Society of America Journal, Vol. 40, No. 6, p 880-882, November-
December 1976. 2 fig, 3 tab, 17 ref.
Descriptors: Soil properties. Soil investigations. Soil chemistry. Soil chemical
properties. Laboratory tests.
Soil solution is obtained by immiscible displacement using centrifugation in the
presence of an excess of carbon tetrachloride. A combination glass electrode is
then introduced into the soil solution which is floating on top of the carbon
tetrachloride. By ke'eping the system closed, changes in pH induced by loss or
gain of carbon dioxide are avoided. No water need be added to a naturally occur-
ing soil so changes in pH induced by the dilution effect and/or the salt effect
are obviated. There is no contact between reference electrode and soil parti-
cles so there is considered to be no junction error involved in the measurement.
The technique is simple and reasonably convenient; the readings are stable and
apparently reliable.
76:02G-034
SOIL AIR PRESSURE EFFECTS ON ROUTE AND RATE OF INFILTRATION,
Linden, D.R., and Dixon, R.M.
United States Department of Agriculture, Minnesota University, Department of
Soil Science, Saint Paul, Minnesota.
Soil Science Society of America Journal, Vol. 40, No. 6, p 963-965, November-
December 1976. 3 fig, 7 ref.
Descriptors: *Infiltration. Soil water. Soil moisture. Soil properties. Soil
investigations. Soils.
One centimeter of 0.1% methylene blue solution was infiltrated into soil with
various constant soil air pressures beneath the wetting surface to measure flow
into and through soil macropores. Flow was increasingly impeded as soil air
pressure increased from 0 to 5 mbars. Infiltration rates during the first 3 min
of wetting were decreased by an order of magnitude with 5 mbars of air-back
pressure.
76:02G-035
MASS TRANSFER STUDIES IN SORBING POROUS MEDIA I. ANALYTICAL SOLUTIONS,
van Genuchten, M. Th., and Wierenga, P.J.
Princeton University, Department of Agronomy, Princeton, New Jersey.
Soil Science Society of America Journal, Vol. 40, No. 4, p 473-480, July-August
1976. 6 fig, 26 ref.
Descriptors: *Mass transfer, *Porous media, *Adsorption, Analytical techniques,
Soils, Soil properties, Soil chemistry. Soil water movement.
An analytical solution is presented for the movement of chemicals through a
sorbing porous medium with lateral or intra-aggregate diffusion. The liquid
phase in the porous medium is divided into mobile and immobile regions. Diffu-
sional transfer between the two liquid regions is assumed to be proportional to
the concentration difference between the mobile and immobile liquids. Sorption
processes in both the dynamic and stagnant regions of the medium are assumed to
be instantaneous and the adsorption isotherm is assumed to be linear. The
analytical model derived here describes the extensive tailing observed during
flow through an unsaturated, aggregated sorbing medium and explains the often
observed early breakthrough of chemicals in the effluent.
76:02G-036
DETERMINATION OF SOIL-WATER DIFFUSIVITY FOR ANISOTROPIC STRATIFIED SOILS,
Sawhney, B.L., Parlange, J.-Y., and Turner, N.C.
46
-------
The Connecticut Agricultural Experiment Station, Department of Soil Chemistry,
New Haven, Connecticut.
Soil Science Society of America Journal, Vol. 40, No. 1, p 7-9. January-February
1976. 3 fig, 10 ref.
Descriptors: *Diffusivity, *Infiltration, Stratification, Soils, Soil investi-
gations, Soil properties.
The unsaturated soil-water diffusivity of an anisotropic soil can be described
by a second-order tensor. In the particular case of a stratified soil, the
diffusivity tensor is defined by the two values of the diffusivity in the prin-
cipal directions, one normal and one parallel to the soil layer. The standard
method of Bruce and Klute then requires the use of two soil columns, one for
each direction, to define the diffusivity tensor. The present method makes use
of a two-dimensional similarity solution first derived for an isotropic medium
and extended here to a stratified soil. It is then possible to obtain the
diffusivity tensor of the stratified soil from one experiment only. As an
illustration of the method, the diffusivity tensor of a mica layer is measured
and the result is used to analyze infiltration from a finite trench.
76:026-037
COMPARISONS OF CALCULATED AND MEASURED CAPILLARY POTENTIALS FROM LINE SOURCES,
Thomas, A.W., Duke, H.R., Zachmann, D.W., and Kruse, E.G.
United States Department of Agriculture, Agricultural Engineering, Watkinsville,
Georgia.
Soil Science Society of America Journal, Vol. 40, No. 1, p 10-14, January-February
1976. 4 fig, 2 tab, 11 ref.
Descriptors: *Infiltration, *Subsurface irrigation, Irrigation, Capillary
action. Hydraulic conductivity. Model studies, Soil moisture.
This paper is a sequel to D.W. Zachmann and A.W. Thomas' (1973) development of
equations describing steady infiltration from line sources. Calculated distri-
butions of capillary potentials are compared with those measured in a soil bin
designed to model the water distribution from a subsurface irrigation system.
Limitations of the steady-state equations for predicting capillary potentials
are given. A procedure for selecting lateral depth and spacing to attain a
given matric flux potential is also given.
76:020-038
BULK DENSITY, SATURATION WATER CONTENT AND RATE OF WETTING OF SOIL AGGREGATES,
Gumbs, F.A., and Warkentin, B.P.
West Indies University, Department of Soil Science, Trinidad, West Indies.
Soil Science Society of America Journal, Vol. 40, No. 1, p 28-33, January-
February 1976. 4 fig, 5 tab, 12 ref.
Descriptors: *Bulk density, *Soil properties. Soils, Soil investigations,
Porosity, Evaporation, Soil aggregates. Soil moisture, Sorption, Infiltration,
Clays, Pores.
Bulk density, degree of saturation, volume increase on wetting, and rate of wet-
ting were measured for aggregated and clods of Ormstown silty clay loam
(Humaquept) of sizes from 5 cm to 0.036 cm diameter. Bulk density increased
with a decrease in diameter. For 2.2-mm to 0.36-mm diameter aggregates this
increase was due to a surface area effect, i.e., loss in porosity as a result
of subdividing larger aggregates. Both surface area effects and increased
porosity from root'channels and fissures were required to explain the increase
for clods between 5 and 1 cm diameter. An evaporation and a sorption technique
are described and used to estimate the water content of aggregates at saturation,
i.e., the intra-aggregate water content. The evaporation technique gave reli-
able results at specific rates of evaporation, but the sorption technique was
not as useful. Clods and aggregates of the soil and of pumice samples did not
fully saturate; entrapped air accounted for 25 to 27% of the total pore volume.
Aggregates of 1 and 2.2 mm diameter and clods of 1.0 and 5.0 cm diameter took
about 1, 1.7, 45, and 1,000 seconds, respectively, to saturate. This rapid wet-
ting would minimize differences in potential between inter-and intra-aggregate
water during infiltration.
47
-------
76:02G-029
SOIL-HEAT FLUX DETERMINATION: TEMPERATURE GRADIENT METHOD WITH COMPUTED THERMAL
CONDUCTIVITIES,
Kimball, B.A., Jackson, R.D., Nakayama, F.S., Idso, S.B., and Reginato, R.J.
United States Water Conservation Laboratory, 4331 East Brasdway, Phoenix,
Arizona.
Soil Science Society of America Journal, Vol. 40, No. 1, p 25-28, January-
February 1976. 1 fig, 2 tab, 13 ref.
Descriptors: *Thermal conductivity, *Heat flow.
Soil properties.
Soils, Soil investigations.
Surface soil-heat fluxes were determined for 6 days in a field of Avondale loam
using the null-alignment method, the combination method, and four variations of
the temperature gradient method with thermal conductivities computed from the
DeVries' theory for particular reference depths. For all methods, calorimetry
was used to obtain the surface flux from the flux determined for the reference
depth. There was 10% or less difference between the null-alignment, combination,
and temperature gradient methods for a 20-cm reference depth. However, the
difference with respect to the null-alignment method increased to 35% for a 5-cm
reference depth when DeVries' theory was closely followed. This difference
was reduced to 3% when a modified air shape factor was used in the computations
and all vapor movement was ignored. We concluded that the temperature gradient
method with conductivities computed from DeVries' theory could be reliably
used with a 20-cm reference depth, but that a "calibration" of the theory for
a particuulr soil should be obtained before the method is used with a 5-cm
reference depth.
76:02G-040
COMPARISON OF FIELD-MEASURED AND CALCULATED SOIL-HEAT FLUXES,
Kimball, B.A., Jackson, R.D., Reginato, F.S., Nakayama, F.S., and Idso, S.B.
United States Water Conservation Laboratory, 4331 East Broadway, Phoenix,
Arizona.
Soil Science Society of America Journal, Vol. 40, No. 1, p 18-25, January-
February 1976. 5 fig, 1 tab, 32 ref.
Descriptors: *Soil temperature, *Thermal conductivity, *Heat flow, Soils, Soil
investigations. Water vapor. Temperature, Soil water movement.
Soil-heat fluxes calculated using DeVries' theory (1958, 1963) were compared
with those experimentally determined in a field of Avondale loam at Phoenix,
Arizona, on 6 days representing different seasons of the year. A fair agree-
ment between measured and computed fluxes was obtained only after modifying the
air shape factor curve and ignoring heat transfer due to water vapor movement.
The omission of the latter implied that heat transfer by pure conduction was
most important and that thermal and isothermal vapor fluxes exactly cancelled
during the day and were insignificant at night. "Measured" thermal conductiv-
ities were also determined from the ratio of the measured heat fluxes to the
corresponding temperature gradient for those times when it was unlikely that
isothermal vapor movement was significant. The lack of a temperature dependence
in these data, as well as the flux comparisons, strongly indicate that the
theory over estimated thermal vapor movement. These data plus others in the
literature indicate that an individual "calibration" of the theory for a parti-
cular soil is required before reliable predication of soil-heat flux can be
obtained.
76:02G-041
SOIL MOISTURE FLUX AND EVAPOTRANSPIRATION DETERMINED FROM SOIL HYDRAULIC
PROPERTIES IN A CHAPPARAL STAND,
Scholl, D.G.
Rocky Mountain Forest and Range Experiment Station, 5423 Federal Building,
517 Gold Avenue Southwest, Albuquerque, New Mexico.
Soil Science Society of America Journal, Vol. 40, No. 1, p 14-18, January-
February 1976. 3 fig, 1 tab, 11 ref.
Descriptors: *Soil moisture, *Soils, *Soil properties, *Evapotranspiration,
48
-------
Model studies, Water balance, Overland flow. Soil water movement, Hydraulic
conductivity -
Measurements of rainfall, overland flow, soil moisture, and hydraulic properties
were obtained from a sloping plot in a chaparral stand. The moisture character-
istic and dynamic conductivity were determined from core samples of several soil
layers to a depth of 420 cm. A water balance model requiring the above para-
meters and a Darcian moisture flux analysis was used to predict drainage below
the root zone and loss by evapotranspiration. Daily results of the water
balance were summarized during 2 water years. Predicted values agreed well with
values measured on a nearby watershed during both years—the first an unusually
dry year, the second unusually wet.
76:020-042
METHYLATION OF MERCURY IN AGRICULTURAL SOILS,
Rogers, R.D.
United States Environmental Protection Agency, Office of Research and Develop-
ment, Soil Microbiology, Las Vegas, Nevada.
Journal of Environmental Quality, Vol. 5, No. 4, p 454-458, October-December
1976. 7 tab, 24 ref.
Descriptors: Agricultural soils, Mercury, Soil texture, Soil moisture, Soil
temperature, Soils, Soil investigations.
Methylation of applied divalent mercury ion was found to occur in agricultural
soils. The production of methylmercury was affected by soil texture, soil
moisture content, soil temperature, concentration of the ionic mercury amend-
ment, and time. Methylation was directly proportional to clay content, moisture
content, temperature, and mercury concentration. After an initial build-up of
methylmercury in the soil, there appeared to be a mechanism that decreased
the methylmercury content with increasing time.
76:020-043
NITRATE-NITROGEN MOVEMENT THROUGH SOIL AS AFFECTED BY SOIL PROFILE CHARACTER-
ISTICS,
Devitt, D., Letey, J., Lund, L.J., and Blair, J.W.
California University, Department of Soil Science and Agricultural Engineering,
Riverside, California.
Journal of Environmental Quality, Vol. 5, No. 3, p 283-288, July-September
1976. 4 fig, 2 tab, 14 ref.
Descriptors: *Nitrogen, Soil investigations, Manganese, Chlorides,
Denitrification, Leaching, Irrigation practices.
The contribution of agricultural practices to pollution of ground and surface
waters by nitrogen is not completely known. Six tile systems installed on
commercial farms with differing soil profile characteristics were selected
for investigation. Soil solution samples were extracted from 61-, 91-, 122-,
and 183-cm depths and analyzed for nitrate-nitrogen, manganese, and chloride
concentrations, and electrical conductivity. Redox potential measurements were
made at 91-and 183-cm depths. Tensiometers were installed at 61-, 91-, and 122-
cm depths to measure hydraulic gradients. Tile effluent samples were also
collected and analyzed. Data on redox potential, manganese concentrations, and
nitrate-nitrogen concentration and movement were dependent on water movement
and amounts of nitrate available for leaching. Irrigation management to provide
low leaching fraction resulted in relatively higher nitrate-nitrogen concentra-
tion in the tile effluent but smaller amounts of total nitrate lost as compared
to irrigation management for high leaching fractions. Redox potentials and
the chloride to nitrate-nitrogen ratios indicated that subsurface layers of
high clay content promote denitrification. With one exception, a smaller
fraction of the applied nitrogen was lost in the tile effluent from profiles
containing layers of high clay content as compared to the coarse-textured
profiles.
49
-------
76:02G-044
INFLUENCE OF PESTICIDES ON DENITRIFICATION IN SOIL AND WITH AN ISOLATED
BACTERIUM,
Bollag, J.-M., and Henninger, N.M.
Pennsylvania State University, Department of Soil Microbiology, University
Park, Pennsylvania.
Journal of Environmental Quality, Vol. 5, No. 1, p 15-18, Jamuary-March 1976.
2 fig, 3 tab, 8 ref.
Descriptors: *Pesticides, *Denitrification, Insecticide, Inhibition, Fungicides,
Herbicides, Anaerobic conditions.
Various pesticides were tested for their influence on the denitrification
process in soil and on an isolated denitrifying bacterium. In soil the denitri-
fying activity was essentially inhibited by the fungicides captan, maneb, nabam,
and to a lesser extent by the herbicide 2,4-D. In pure culture-studies with
a bacterium whose end product in denitrification was nitrous oxide, the fungi-
cides also caused strong, inhibition of the respiratory nitrate reduction process;
the insecticide carbaryl, the phenylurea herbicides, 2,4-D and propham (isopropyl
carbanilate) also functioned as inhibitors, but to a lesser extent. It was of
special interest to observe that the inhibition by certain perticides influenced
the formation rate of nitrite and sometimes prevented the reduction of accumula-
ted nitrite during incubation under anaerobic conditions.
76:020-045
FATE OF FERTILIZER NITROGEN IN A FLOODED RICE SOIL,
Patrick, W.H. Jr., and Reddy, K.R.
Louisiana State University, Laboratory of Flooded Soils and Sediments, Depart-
ment of Agronomy, Louisiana Experiment Station, Baton Rouge, Louisiana.
Soil Science Society of America Journal, Vol. 40, No. 5, p 678-681, September-
October 1976. 3 fig, 4 tab, 11 ref.
Descriptors: *Rice, *Fertilization, Nitrogen, Nutrients, Soil investigations,
Flood irrigation, Irrigation effects. Irrigation.
In order to improve the efficiency of fertilizer N utilization by rice, it is
important to know what happens to N applied to the soil. Field experiments
utilizing N15-enriched ammonium sulfate were carried out to determine the fate
of fertilizer N (100 kg N/ha) applied to Crowley silt loam soil. The distri-
bution of fertilizer N in the plant-soil system at harvest time was determined
using 2.32 sq m plots. The distribution of fertilizer N in the plant-soil-
floodwater system at six times during the growing season was measured in smaller
plots (0.28 sq m). The results from the larger plots showed that fertilizer N
recovered in the grain ranged from 30.9 to 37.3 kg N/ha depending on the method
of application. Recovery of fertilizer N in the straw ranged from 18.2 to 24.2
kg N/ha. A considerable portion of fertilizer N (24.2 to 27.1 kg N/ha) remained
in the soil (including roots) after cropping. Total recovery of the 100 kg/ha
addition of labelled fertilizer N in the soil-plant system was 75.0 to 85.6 kg
N/ha for the different methods of N application examined. Experiments using the
smaller 0.28 sq m plots showed rapid uptake of fertilizer N immediately after
application, with no apparent further uptake after about 3 weeks. Soil N was
the major and perhaps sole source of N for the plant during the last part of the
growing season.
76:02G-046
NITRIFICATION-DENITRIFICATION REACTIONS IN FLOODED SOILS AND WATER BOTTOMS:
DEPENDENCE ON OXYGEN SUPPLY AND AMMONIUM DIFFUSION,
Patrick, W.H. Jr., and Reddy, K.R.
Louisiana State University, Louisiana Agricultural Experiment Station, Depart-
ment of Agronomy, Baton Rouge, Louisiana.
Journal of Environmental Quality, Vol. 5, No. 4, p 469-472, October-December
1976. 5 fig, 10 ref.
Descriptors: *Nitrogen, *Denitrification, Oxygen, Anaerobic, Aerobic, Soils,
Soil investigations. Nitrate.
Ammonium nitrogen in a flooded soil or water bottom exposed to oxygen from the
50
-------
water column undergoes sequential nitrification and denitrification. Oxygen
moving through the overlying water column causes the development of an aerobic
surface layer'of soil or sediment. Ammonium in this aerobic surface layer is
nitrified and the resulting ammonium concentration gradient across the aerobic
layer and the underlying anaerobic layer causes ammonium in the anaerobic layer
to diffuse upward into the aerobic layer where it also undergoes nitrififation.
Nitrate produced in the aerobic layer then diffuses downward into the anaerobic
layer where it is denitrified to N2 and N20. Nitrate derived from ammonium
nitrogen in the aerobic layer appears as an intermediate product in the nitrifi-
cation-denitrification reaction. A laboratory experiment utilizing N-15 as a
tracer showed that approximately one-half of the nitrogen involved in the
nitrification-denitrification process was ammonium originally present in the
surface aerobic soil or water bottom layer with the remainder diffusing up from
the underlying anaerobic layer. Where oxygen was absent or limiting, nitrifi-
cation either did not occur or occurred at a lower rate, resulting in a reduced
amount of nitrate available for the denitrification process.
76:02G-047
NITRATE LEAKAGE FROM SOILS DIFFERING IN TEXTURE AND NITROGEN LOAD,
Avnimelech, Y., and Raven, J.
Israel Institute of Technology, Soils and Fertilizers Laboratory, Technion,
Haifa, Israel.
Journal of Environmental Quality, Vol. 5, No. 1, p 79-82, January-March 1976.
1 fig, 1 tab, 10 ref.
Descriptors: *Nitrogen, *Nitrate, *Chloride, Soil profile. Soil texture, Clay
soils, Leaching, Denitrification, Soil investigations, Soils.
Nitrogen and chloride distribution in soil profiles underlying plots differing
in the nitrogen load and soil type were studied in the coastal plain of Israel.
Nitrate leakage was defined as the product of the average nitrate concentration
in subsoil solution times the annual water recharge. A large portion of the
excessive nitrogen (nitrogen load minus nitrogen uptake by the removal crop)
was not recovered.! This portion is high for clay soils and for plots receiving
high nitrogen dressings. Changes in the N03/C1 ratio along the soil profile
coincided with nitrate removal. This data supports the hypothesis that nitrate
removal is mainly due to denitrification in the top layer of the soil.
76:026-048
THE INFLUENCE OF APPLIED PHOSPHORUS, MANURE, OR LIME ON UPTAKE OF LEAD FROM SOIL,
Zimdahl, R.L., and Foster, J.M.
Colorado State University, Department of Botony and Plant Pathology, Fort
Collins, Colorado.
Journal of Environmental Quality, Vol. 5, No. 1, p 31-34, January-March 1976.
3 tab, 17 ref.
Descriptors: *Lead, *Corn, *Phosphorus, Lime, Heavy metals, Soil investigations,
Translocation, Soils.
Studies of the uptake of lead from soil by corn have shown that soil applica-
tions of phosphorus (Ca(H2P04)2 H20) decrease uptake, but translocation was
affected and at higher lead levels. Lead uptake decreased when cow manure
was added to attain a total organic content of 6%, but there was no effect of
additional manure. Liming did not have a consistent effect on uptake, but lead
translocation appeared to decrease with liming. The addition of phosphorus
was not an agronomically feasible way to reduce the effects of lead contamina-
tion, but additions of manure and lime offered promise of reducing lead uptake.
76:02G-049
USE OF THE GREEN-AMPT EQUATION WITH VARIABLE CONDUCTIVITY,
Ahuja, L.R., and Tsuji, G.Y.
Hawaii University, Department of Agronomy and Soil Science, Honolulu, Hawaii.
Soil Science Society of America Journal, Vol. 40, No. 4, p 619-622, July-
August 1976. 2 fig, 13 ref.
Descriptors: Infiltration, Hydraulic conductivity, Soil water, Soil water
movement, Hawaii.
51
-------
A comparison with Philip's two-term equation, derived from a series solution
involving t(l/2), indicates that the hydraulic conductivity in the Green-Ampt
equation of vertical infiltration varies with time when the soil water content
of the transmission zone is assumed to be constant. Use of the Green-Ampt
equation with a continuously variable conductivity or a piecewise application
of the equation as an extension of Philip's two-term equation resulted in
improved prediction of infiltration in two Hawaii soils. Both these forms of
application require three parameters, hydraulic conductivity, sorptivity, and
constant A, which have well-established physical meaning.
76 :02G-050
TRANSIENT MOVEMENT OF WATER AND SOLUTES IN UNSATURATED SOIL SYSTEMS, PHASE II,
Evans, D.D., Sarnmis, T.W. , and Warrick, A.W.
Arizona University, Department of Hydrology and Water Resources.
Available from the National Technical. Information Service, Springfield, Virginia
as PB-261 348, Price codes: A03 in paper copy, A01 in microfiche. Completion
Report, September 1976. 40 p, 14 fig, 9 tab, 12 ref. OWRT B-040-ARIZ(1).
14-31-0001-4059.
Descriptors: *Unsaturated flow, *Tritium, *Soil water movement, *Arizona,
*Solutes, Deep percolation, *Seepage, Methodology, Salts, Aquifers, Water
quality, Pollutant identification, Darcy's Law.
This project yielded results on the movement of water and solutes from beneath
the root zone to a water table aquifer in an irrigated area near Phoenix, Arizona.
Three methods were explored for estimating deep seepage rates. They were: (1)
measurement of the hydraulic conductivities and gradients and by Darcy's equation
calculating the seepage rate; (2) measurement of the temperature profile and
calculating the seepage rate from the shape of the profile curve; and (3) measure-
ment of the tritium concentration of the soil water and relating it to the
history of the tritium concentration of precipitation. The different methods were
used at one site where a deep well was drilled to obtain samples, but the temper-
ature-profile method was tried at other locations. Errors are involved in all
of the methods so results differed. At the principal site of the study the
Darcian velocity estimate (volume of flow per unit area per unit time) ranged
from 9 to 38 cm/yr, while the actual velocity estimate (pore velocity) ranged
from 57 to 130 cm/yr. The results from other sites indicated an even lower
rate of seepage. The solute concentration of the soil water was higher than the
aquifer water but, at the one site, the effect of salts in the seepage water
should not significantly alter the quality of the aquifer water.
76:02G-051
INFLUENCE OF CATION CONTENT ON THE BIOLOGICAL ACTIVITY OF FENSULFOTHION IN
PLAINFIELD SAND,
Harris, C.R., and Bowman, B.T.
Research Institute, Agriculture Canada, University Sub Post Office, London,
Ontario, Canada.
Soil Science Society of America Journal, Vol. 40, No. 3, p 385-389, May-June
1976. 2 fig, 1 tab, 39 ref.
Descriptors: *Cations, *Cation adsorption, *Insecticides, Soils, Soil investi-
gations.
A study was conducted to assess the influence of cations on the biological
activity of the organophosphorus insecticide, fensulfothion in soil. Bioassays
were done using first stage crickets as test insects and a Plainfield sand
without and amended with various concentrations of reagent chloride salts of
NH(4+), K(+), Ca(2+), Fe(3+), and Al(3+). The toxicity of fensulfothion
decreased with increasing cation content, with the effect being most pronounced
with trivalent >divalent > monovalent cations. Results of the bioactivity
study paralleled those of an earlier adsorption study on fensulfothion-cation
montmorillonite suspensions.
76:02G-052
ERROR PROPAGATION IN DETERMINING HYDRAULIC CONDUCTIVITIES FROM SUCCESSIVE WATER
CONTENT AND PRESSURE HEAD PROFILES,
52
-------
Fluhler, H., Ardakani, M.S., and Stolzy, L.H.
California University, Department of Soil Physics, Riverside, California.
Soil Science Society of America Journal, Vol. 40, No. 6, p 830-836, November-
December 1976. 7 fig, 14 ref.
Descriptors: *Hydraulic conductivity, Darcy's Law, Soil water, Soil water move-
ment, Monte Carlo method, Soil investigations.
The flux of water in unsaturated soils can be determined indirectly by using
Darcy's Law. The critical part of this approach is the determination of the
hydraulic conductivity at a given depth and time. In this paper the relative
errors of hydraulic conductivities determined from a transient drainage field
experiment are analyzed. Knowing the errors of this method would be useful in
planning future experiments. It allows putting limitations on the conclusions
to be drawn _from such experiments and it further allows re-examination of already
published field data. In the wet range of the conductivity function errors are
20-30% of the k-value. In the range where k-values are small, the relative
errors may be > 100%. Errors stemming from tensiometer readings are significant
when the hydraulic gradient is < 0.3 mbar . cm(-l). During the early stage of
the transient drainage experiment these errors are always considerable and are
more important than other errors. On the other hand, the errors in the measured
water content changes are dominant when drainage is slowed down due to desatur-
ation of the soil.
76:02G-053
PICLORAM DEGRADATION IN SOILS AS INFLUENCED BY SOIL WATER CONTENT AND TEMPERATURE,
Guenzi, W.D., and Beard, W.E.
United States Department of Agriculture, Department of Soil Science.
Journal of Environmental Quality, Vol. 5, No. 2, p 189-192, April-June 1976.
2 fig, 5 tab, 16 ref.
Descriptors: *Pesticides, *Herbicides, Laboratory tests, Temperature, Soil
investigations. Soils, Field capacity, Pesticide residues, Microbial degradation.
A laboratory experiment was designed to determine the effect of temperature and
alternating incubations at field capacity and during drying periods on the
degradation of picloram in five soils. Picloram was added at a rate of 10 ppm,
and degradation was measured by (C-14) 02 evolution resulting from the cleavage
of the labeled carboxyl carbon. Picloram degraded very little at 5C-and
increased only slightly up to 25C. Three soils were highest in degradation
rates at 30C while two soils were highest at 50C. Picloram degradation rates
during 20-day incubation periods at field capacity, interrupted with 16-day
drying cycles, varied among soils and decreased after each successive drying
cycle at 30 and 50C, except for one soil at 50C. The degradation rate decreased
gradually as water content decreased from field capacity (approximately 0.33 bar)
to 15 bars tension, and ceased after the soils were air dried.
76:02G-054
DEGRADATION OF A NONIONIC SURFACTANT IN SOILS AND PEAT,
Valoras, N., Letey, J., Martin, J.P, and Osborn, J.
California University, Department of Soil Physics, Riverside, California.
Soil Science Society of America Journal, Vol. 40, No. 1,. p 60-63, January-
February 1976. 3 fig, 4 tab, 7 ref.
Descriptors: *Surfactants, Soil water movement. Soils, Soil investigations,
Soil properties. Peat, Adsorption, Soil moisture. Organic matter. Water pollu-
tion, Water quality.
Nonionic surfactants are used to improve water movement into water-repellent
soils. The effective longevity of treatment and potential water pollution are
affected by surfactant degradation. Degradation of C-14-labeled Soil Penetrant
3685, a nonionic surfactant, was measured in incubation studies in the labora-
tory. Three soils and one peat, numerous surfactant concentrations, and two
soil-moisture levels were used as experimental variables. Plots of degradation
percentage versus time produced "S" type curves. Increasing the concentration
increased the lag period prior to most rapid degradation. The most rapid and
highest percentageof degradation were generally associated with soil materials
53
-------
having the lowest adsorptive capacity for the surfactant. From about 75 to 85%
of the C-14 was evolved as (C-14) 02 in 1 year for the most favorable conditions
for degradation. Degradation rate was decreased by decreasing the soil-moisture
content. Degradation of soil organic matter was not greatly affected by surfact-
ant applications--< about 10,000 ppm, but progressively decreased with higher
surfactant concentrations.
76:02G-055
SIMULTANEOUS TRANSPORT OF NITRATE AND GASEOUS DENITRIFICATION PRODUCTS IN SOIL,
Rolston, D.E., and Marino, M.A.
California University, Department of Land, Air, and Water Resources, Davis,
California.
Soil Science Society of America Journal, Vol. 40, No. 6, p 860-865, November-
December 1976. 5 fig, 2 tab, 17 ref.
Descriptors: Fertilizer, Fertilization, Nitrates, Denitrification, Soil proper-
ties, Soil investigations, Soil water, Soil water movement. Leaching.
A pulse of N03{-) fertilizer tagged with N-15 was applied to 100 cm long Yolo
loam (Typic xerorthents) topsoil and subsoil columns maintained uniformly
unsaturated at soil-water pressure heads between 20-: and 140- cm of water at
soil-water fluxes between 1.0 and 0.1 cm day(-l). Nitrate, molecular nitrogen,
and nitrous oxide from the applied fertilizer were measured as a function of soil
depth and time until the N03(-) pulse eluted from the column. An analytical
solution describing the transport and transformation of N03(-) was used to
determine values for the first-order denitrification rate constants within the
columns. A numerical solution of the coupled equations for transport and
transformation of N03(-) and diffusion of the gaseous denitrification products
was compared with measured N2 and N20 concentration profiles within columns.
The gaseous concentration profiles were very much dependent upon values of the
denitrification rate constant and the soil gaseous diffusion coefficient. Values
of the soil gaseous diffusion coefficient, more than an order of magnitude small-
er than those values measured in the upper part of the column, were required to
approximately fit the numerical solution to the measured gas concentration
profiles.
76:020-056
AMMONIUM DIFFUSION AS A FACTOR IN NITROGEN LOSS FROM FLOODED SOILS,
Reddy, K.R., Patrick, W.H. Jr., and Phillips, R.E.
Louisiana State University, Department of Agronomy, Baton Rouge, Louisiana.
Soil Science Society of America Journal, Vol. 40, No. 4, p 528-533, July-August
1976. 6 fig, 2 tab, 36 ref.
Descriptors: *Nitrogen, *Leaching, Nitrification, Denitrification, Soil
investigations, Ammonium compounds. Anaerobic conditions, Aerobic conditions.
The role of NH4(+)-N diffusion in a flooded soil on nitrogen (N) loss through
the nitrification-denitrification process was investigated under laboratory
conditions. The distribution of applied NH4(+)-N in both the aerobic and anaer-
obic soil layers of a flooded soil was experimentally determined and compared with
the values obtained from theoretical equations. The total loss of NH4(+)-N from
the flooded soil system (15cm depth) by nitrification-denitrification was
equivalent to 12.43 g N/sq m for a 120-day incubation period when the initial
concentration of NH4(+)-N was 44.84 g N/sq m. Diffusion of NH4(+)-N from the
anaerobic soil layer to the aerobic soil layer accounted for more than 50%
(7.16 g N/sq m) of the total NH4(+)-N loss with the remainder being lost from
NH4(+)-N originally present in the aerobic layer. The NH4(+)-N that diffused
upward into the aerobic soil layer was nitrified to N03(-)-N, which readily dif-
fused back down into the anaerobic soil layer and was subsequently denitrified.
76:02G-057
SAMPLING THE UNSATURATED ZONE OF IRRIGATED LANDS FOR RELIABLE ESTIMATES OF
NITRATE CONCENTRATIONS,
Rible, J.M., Nash, P.A., Pratt, P.F., and Lund, L.J.
California University, Department of Soil Science, Riverside, California.
Soil Science Society of America Journal, Vol. 40, No. 4, p 566-570, July-August
54
-------
1976. 5 fig, 5 tab, 9 ref.
Descriptors: *Nitrate, *Nitrogen, Soils, Soil properties. Soil investigations.
Data from a study of 56 field sites were used to examine the variability of
nitrate-nitrogen concentrations in the unsaturated zone underneath the root zone.
The specific data were nitrate-nitrogen concentrations in soil water in samples
taken at 0.9-m intervals from the 4.5- to 11.9-m depth from four holes per site.
Analyses of variance of these data provided estimates of variances that were
used to predict the depth sampling interval and the number of holes required for
means to be within the confidence limits of 10, 20, and 30%. Calculations
were based on sampling intervals of 0.9, 0.6, and 0.3 m providing 9, 13, and
26 samples per hole, respectively. Relationships developed between number of
sites, number of holes required, sampling interval, and confidence limits were
used to test selected sampling plans for degree of precision in comparison with
the actual sampling procedure. A cost analysis of the field study indicated that
it would cost three to four times more than the field study to use a sampling
plan which would reasonably ensure that 75% of the sites' true means fall within
20% of the measured means at a confidence level of 95%.
76:02G-058
EVALUATION OF THE PARAMETERS OF SOIL PHOSPHORUS AVAILABILITY FACTORS IN PREDICT-
ING YIELD RESPONSE AND PHOSPHORUS UPTAKE,
Dalai, R.C., and Hallsworth, E.G.
New England University, Department of Agronomy and Soil Science, Armidale,
New South Wales, Australia.
Soil Science Society of America Journal, Vol. 40, No. 4, p 541-546, July-August
1976. 1 fig, 5 tab, 37 ref.
Descriptors: *Phosphorus, Nutrients, Crop production, Crop response, Wheat.
The importance of quantity, intensity, capacity, and rate factors of soil P
availability to account quantitatively for the variation in P uptake and wheat
grain yield in pot and field experiments was studied. Among the parameters of
the quantity factor, L value was found to be highly correlated with P uptake at
35 and 150 days after planting (maturity) when all the soils were considered.
However, the carbonate P was found to be the best parameter of the quantity
factor when the s6ils containing high amounts of hematite/goethite were excluded.
The parameters of the intensity factor were significantly correlated with P
uptake at the later stage (150 days). The rate factor, as measured by AER was
better correlated with P uptake at 35 days than with P uptake at 150 days after
planting. The quantity factor as measured by the carbonate P accounted for 75
and 93% of the variation in P uptake and grain yield, respectively. The capacity
factor, Mb when combined with the quantity factor accounted for more of the
variation in p uptake (150 days) from 75 to 86%. The intensity and the rate
factors had a smaller effect.
76:02G-059
CHANGES IN THE PHYSICAL PROPERTIES OF SOIL CLAYS DUE TO PRECIPITATED ALUMINUM
AND IRON HYDROXIDES: II. COLLOIDAL INTERACTIONS IN THE ABSENCE OF DRYING,
El-Swaify, S.A.
Hawaii University, Department of Soil Science, Honolulu, Hawaii.
Soil Science Society of America Journal, Vol. 40, No. 4, p 516-520,July-August
1976. 6 fig, 13 ref.
Descriptors: *Clays, *Flocculation, Soils, Soil properties, Soil investigations.
Soil chemistry, Soil chemical properties.
Colloidal stability diagrams were constructed for suspensions of an illite, a
kaolinite, and a mixture of the two into which A1(OH)3 and Fe()H)3 were precipi-
tated. These diagrams covered a pH range form 2.5 to 12.5 and electrolyte
concentrations up to the flocculation value. It was revealed, in accordance
with expected interactions of colloids with widely different isoelectric points,
that the colloidal stability of each mixture was dependent on the charge balance
between its individual constituents. Therefore, as long as a system has not
encountered a drying cycle, hydroxides may provide favorable (flocculating) or
non-favorable (colloidally stable) effects on soil structure depending on hydrox-
55
-------
associated. Generally, the two hydroxides provided equal enhancement of clay
colloidal stability above their isoelectric points. However, A1(OH)3 was more
active in inducing clay flocculation and charge reversal at low pH values.
76:02G-060
UPTAKE OF CADMIUM BY SOYBEANS AS INFLUENCED BY SOIL CATION EXCHANGE CAPACITY,
PH, AND AVAILABLE PHOSPHORUS,
Miller, J.E., Hassett, J.J., and Koeppe, D.E.
Argonne National Laboratory, Argonne, Illinois.
Journal of Environmental Quality, Vol. 5, No. 2, p 157-160, April-June 1976.
1 fig, 5 tab, 21 ref.
Descriptors: *Cadmium, Cation exchange, Phosphorus, Greenhouses, Heavy metals.
The accumulation of cadmium and its affect on vegetative growth of soybeans in
soils with a range in cation exchange capacity (CEC), pH and available phosphorus
(P) were investigated in greenhouse experiments. Cadmium uptake decreased as
soil pH and CEC increased, while increasing available soil P was related to
increased Cd accumulation. Cadmium extracted from the soil by Bray PI reagent,
Bray P2 reagent, 2N MgC12, and 0.1N EDTA was significantly correlated with plant
Cd concentrations. The growth of the soybean shoots was generally depressed
when tissue concentrations reached 3-5 micro g Cd/g dry weight. Cadmium uptake
by soybeans was correlated with the ratio of added Cd to the Cd sorptive capacity
of soil.
76:026-061
NITRITE DECOMPOSITION IN FLOODED SOIL UNDER DIFFERENT PH AND REDOX POTENTIAL
CONDITIONS,
Van Cleemput, O., Patrick, W.H. Jr., and Mcllhenny, R.C.
Louisiana State University, Louisiana Agricultural Experiment Station,
Department of Agronomy, Baton Rouge, Louisiana.
Soil Science Society of America Journal, Vol. 40, No. 1, p 55-60, January-
February 1976. 4 fig, 3 tab, 32 ref.
Descriptors: Soils, Soil investigations. Soil properties, Soil chemistry,
Nitrites, Sterilant, Soil sterilants.
Nitrite decomposition products were studied in a flooded soil suspension
maintained under different pH and redox potential conditions. The effect of a.
sterilant, HgC12, on nitrite breakdown was also investigated. Soil suspensions
were incubated for several days with the pH maintained at 4.5, 6, and 8 and
the redox potential maintained at 0 and +200 mV. Nitrite was then added to the
suspensions and the decomposition products were determined by mass spectrometry.
Under acid conditions signigicant amounts of N2 and nitrogen oxide gases (N20,
NO) were formed in both the moderately reduced (+200 mV) and reduced (0 mV)
suspensions. At higher pH's the nitrite reduction rate was slightly less and
the amounts of nitrogen oxide gases formed were considerably less with N2 being
the major product. The chemical sterilant decreased the conversion of nitrite
to N2 and markedly increased the formation of NO. The significant production of
NO under acid conditions both with and without the sterilant, suggests the
likelihood of self-decomposition of nitrous acid as a major mechanism of nitrite
loss.
76:02G-062
RELEASE OF CADMIUM FROM CLAYS AND PLANT UPTAKE OF CADMIUM FROM SOIL AS AFFECTED
BY POTASSIUM AND CALCIUM AMENDMENTS,
Haghiri, F.
Ohio Agricultural Research and Development Center, and the Ohio State University,
Wooster, Ohio.
Journal of Environmental Quality, Vol. 5, No. 4, p 395-397, October-December
1976. 2 tab, 11 ref.
Descriptors: *Cadmium, *Potassium, Clays, Calcium, Kaolinite, Illite, Soybeans,
Heavy metals, Soil amendments.
The effects of percent K and/or Ca saturation on the release of Cd from Cd-treated
H-clays (kaolinite and illite) and on the Cd availability to plants from Cd-
56
-------
treated Canfield silt loam soil were determined. The concentration of Cd in the
dialyzates from both kaolinite and illite clays increased as the percent Ca or
K saturation of the clays in the suspension decreased. The release of Cd from
both clays was greater in the presence of Ca than K. In a separate experiment,
the concentration of Cd in soybean shoots (Glycine max L. Merr.) "Corsoy"
decreased with increasing percent Ca or K saturation of the soil. The results
indicated that Cd uptake by soybean shoots could be impaired to a great extent
by K application.
76:020-063
SOLUBILITY AND SOLUBILITY PRODUCT OF DICALCIUM PHOSPHATE DIHYDRATE IN AQUEOUS
SOLUTIONS AND SOIL SOLUTIONS,
Bennett, A.C., and Adams, F.
Auburn University Agricultural Experiment Station, Department of Soils, Auburn,
Alabama.
Soil Science Society of America Journal, Vol. 40, No. 1, p 39-42, January-
February 1976. 3 tab, 10 ref.
Descriptors: *Phosphates, Soils, Soil investigations, Soil properties,
Solubility.
The solubility product (Ca(2+)) of CaHP04 . 2H20 was determined in several
aqueous solutions containing ions common to soil solutions. Extrapolation of
analytical Ca and P concentrations to zero ionic strength yielded pK(sp) values
ranging from 6.54 to 6.59 and averaging 6.57 for 10 aqueous salt solutions. A
method of successive approximation that computed ionic activity was used to
determine the pK(sp) for three concentrations of 15 different aqueous salt
solutions saturated with CaHP04 . 2H20. Calculated pK(sp) values ranged from
6.44 to 6.63; the average was 6.55. Eight soil samples that varied widely in
pH and soil-test P were treated with CaHP04 . 2H20 at rates of 600 to 3,000 ppm
P. Soil solutions were displaced, analyzed, and (Ca(2+)) (HPO4(2-)} was
calculated. Eight of the 20 samples of soil were considered to be saturated
with CaHP04 . 2H20 because their (Ca(2+)) (HP04(2-)) values were approximately
the same as that for similar aqueous salt solutions. It was concluded that the
presence of excess CaHP04 . 2H20 in soil could be inferred by ion-activity
products of displaced soil solutions.
76:020-064
AMMONIA VOLATILIZATION FROM SURFACE APPLICATIONS OF AMMONIUM COMPOUNDS ON
CALCAREOUS SOILS: V. SOIL WATER CONTENT AND METHOD OF NITROGEN APPLICATION,
Fenn, L.B., and Escarzaga, R.
Texas Agricultural Experiment Station, Texas A and M Research Center at El Paso
10601 North Loop Road, El Paso, Texas.
Soil Science Society of America Journal, Vol. 40, No. 4, p 537-541, July-August
1976. 2 fig, 1 tab, 14 ref.
Descriptors: *Nitrogen, Fertilization, Nutrients, Temperature, Ammonia,
Ammonium compounds, Calcareous soils, Soil water.
Ammonia-nitrogen losses from soils were dependent on the existence of sufficient
water solubilization of the applied NH4-compounds. Laboratory data revealed that
NH3 volatilization from (NH4)2S04 was greatly reduced on soils with 55% water
at 12, 22, and 30 degrees C as compared to soils with 30% water. Ammonia-
nitrogen losses were the highest at all temperatures and nitrogen application
rates when soils contained 13 to 30% soil water. Dry NH4-chemicals did not
dissolve in soils with 0 and 8% soil water, therefore, little NH3 was lost.
Application of a concentrated (NH4)2S04 solution to soils with 8% water resulted
in near maximum NH3 loss. This same solution, when applied to the surface of
an oven dry soil, resulted in lower losses. Application of NH4N03 to soils
with 55% water resulted in lower NH3 losses when compared to soils with 8 to 30%
water. Soils with 0% water retained essentially all applied NH4(+)-N whether
applied in dry or concentrated liquid form.
76:02G-065
THE INFLUENCE OF CATION EXCHANGE CAPACITY AND DEPTH OF INCORPORATION ON AMMONIA
VOLATILIZATION FROM AMMONIUM COMPOUNDS APPLIED TO CALCAREOUS SOILS,
57
-------
Fenn, L.B., and Kissel, D.E.
Texas A and M Research Center at El Paso, Texas 10601 North Loop Road, El Paso,
Texas.
Soil Science Society of America Journal, Vol. 40, No. 3, p 394-398, May-June
1976. 2 fig, 3 tab, 15 ref.
Descriptors: *Cation exchange, *Calcareous soils, Soils, Soil properties,- Soil
investigations, Soil chemistry, Model studies.
The objective of this study was to determine the influence of soil cation
exchange capacity (CEC) and depth of incorporation on NH3-N volatilization from
NH4(+)-N compounds applied to calcareous soil. This study was conducted in the
laboratory on soils with a wide range of CEC. An increasing CEC resulted in
decreasing NH3 losses. Ammonium sulfate produced higher soil pH values and NH3
losses than did NH4N03. The pH of the soil decreased with increasing NH4NO3
application rates. With NH4N03, percent NH3(-)N losses increased as the applica-
tion rates increased. Incorporation of the NH4(+)-compounds into the soil
reduced NH3 losses. Increasing depths of NH4(+)-incorproation resulted in
reduced NH3 loss. Losses decreased as the CEC of soil increased. The effect-
iveness of soil depth in reducing NH3 loss was associated with soil water
content. Decreasing the soil water increased the effectiveness of soil incor-
poration for reducing NH3 losses.
76:02G-066
COMMENTS ON NITRATE REDUCTION IN UNSATURATED SOIL,
McLaren, A.D.
California University, Department of Soil Biology, Berkeley, California.
Soil Science Society of America Journal, Vol. 40, No. 5, p 698-699, September-
October 1976. 1 fig, 12 ref.
Descriptors: Nitrite, Nitrate, Ions, Soils, Soil investigations, Nitrification.
Cyclic oxidation and reduction of nitrite and nitrate in soil are analyzed in
terms of first-and zero-order microbial kinetic reactions, respectively. A
reversible reaction step involving these ions can account for a low, but constant
concentration of nitrate in an unsaturated field soil for long periods or for
considerable depths in a laboratory soil column.
76:02G-067
RADIAL MOVEMENT OF SATURATED ZONE UNDER CONSTANT FLUX: THEORY AND APPLICATION
TO THE DETERMINATION OF SOIL-WATER DIFFUSIVITY,
Sawhney, B.L., and Parlange, J.-Y.
Connecticut Agricultural Experiment Station, New Haven, Connecticut.
Soil Science Society of America Journal, Vol. 40, No. 5, p 635-639, September-
October 1976. 3 fig, 11 ref.
Descriptors: Soil water, Soil water movement, Diffusivity, Soils, Soil
investigations. Soil moisture.
A two-dimensional similarity solution yields the soil-water diffusivity of an
unsaturated soil when the soil water content is measured as a function of the
distance from the source. When ponding occurs, the positions of the saturated
and unsaturated fronts are related to the diffusivity. If the diffusivity can
be described with two parameters, it can be predicted from the position of the
two fronts alone without measuring the moisture profile. Four experiments with
a fine sandy loam at two different flow rates were performed to determine the
diffusivity from the position of the two fronts. The moisture profile was then
predicted from the measured diffusivity. The predictions are in good agreement
with the observations.
76:02G-068
MICROBIAL FORMATION OF VOLATILE SELENIUM COMPOUNDS IN SOIL,
Doran, J.W., and Alexander, M.
Cornell University, Department of Agronomy, Ithaca, New York.
Soil Science Society of America Journal, Vol. 40, No. 5, p 687-690, September-
October 1976. 3 fig, 2 tab, 18 ref.
58
-------
Descriptors: Selinium, Soil, Soil investigations, Microbial formation, Soil
chemistry, Soil properties.
Selenium was volatilized from soils amended with elemental Se, selenite, selenate,
trimethylselenonium chloride, selenomethionine, and selenocystine and incubated
in air or anaerobically. The processes were wholly or largely the result of
microbial action. The conversion of selenite and selenate to volatile products
was enhanced if soil was amended with organic materials. Indigenous soil Se was
also volatilized in the presence of supplemental organic matter. The products
were identified by combined gas chromatography-mass spectrometry. Dimethyl
selenide was generated from all Se compounds tested when amended soils were
incubated in the presence of air. Under anaerobic conditions, dimethyl selenide
was produced from the three organic Se compounds and selenate, and a product
tentatively identified as hydrogen selenide (H2Se) was evolved from soil receiving
elemental Se, selenite, selenate, or selenocystine. Dimethyl diselenide was also
formed from selenomethionine in soil incubated in air or anaerobically.
76:02G-069
TILE DRAINAGE IN BEDDED SOIL OR A DRAW,
Powell, N.L., and Kirkham, D.
Virginia Polytechnical Institute and State University, Department of Agronomy,
Blacksburg, Virginia.
Soil Science Society of America Journal, Vol. 40, No. 5, p 625-630, September-
October 1976. 5 fig, 1 tab, 24 ref.
Descriptors: Drainage, Drainage effects, Drainage practices, Tile drains, Tile
drainage, Furrow irrigation, Darcy's Law, Furrows, Subsurface drains, Subsurface
drainage.
The process of shaping flat land by plowing it into a series of ridges separated
by parallel dead furrow is called bedding and the ridge-furrow systems are called
beds. The furrows are supposed to remove surface water from the ridges, but
often do not. The amount of water that can be removed by tile if they are placed
under the furrows is computed on the basis of Darcy's Law and potential theory.
In the analysis, water-saturated, steady-state conditions and a subsurface barrier
on which the drain tile are laid are assumed. For a poorly drained prairie soil,
the calculations show that tile (or plastic tubes, etc.) placed 0.35 m below the
furrow bottoms and 30 m apart in beds of 2% slope will remove 5 mm of water/day,
and that the bed furrows would have to remove an additional 4.52 mm/day to take
care of an expected drainage coefficient of 9.52 mm/day. For general use, 28
depth and spacing geometries are analyzed and tabulated from amounts of flow to
tile in the beds. For certain geometries, some of the recharge rainfall seeps
in and out of the slope before the water seeps down again into the soil. This
in and out seepage occurs for small tile depths, and small tile sizes. Flow
nets are presented. It is shown that the theory applies to the drainage of a
draw.
76:02G-070
ON THE STOCHASTIC FOUNDATIONS OF THE THEORY OF WATER FLOW THROUGH UNSATURATED
SOIL,
Bhattacharya, R, Gupta, V., and Sposito, G.
Arizona University, Department of Mathematics, Tucson,Arizona.
Water Resources Research, Vol. 12, No. 3, June 1976. 40 ref. OWRT B-046-Ariz
(4). 14-34-0001-6057-
Descriptors: *Hydraulic conductivity, Diffusivity, *Soil water movement,
Stochastic processes, *Unsaturated flow, *Markov processes, Equations, Soil
moisture.
The parabolic differential equation that describes the isothermal isohaline
transport of water through an unsaturated soil is shown to be the mathematically
rigorous result of a fundamental stochastic hypothesis: that the trajectory of
a water molecule is a nonhomogeneous Markov process characterized by space- and
time-dependent coefficients of drift and diffusion. The demonstration is valid
in general for heterogeneous anisotropic soils and provides for three principal
results in the theory of water flow through unsaturated media: (1) a derivation
of the Buckingham-Darcy flux law that does not rely directly on experiment, (2)
a new theoretical interpretation of the soil water diffusivity and the hydraulic
59
-------
conductivity in molecular terms, and (3) a proof that the soil water diffusivity
for anisotropic soil is a symmetric tensor of the second rank. A dynamic argu-
ment at the molecular level is developed to show that the fundamental Markovian
hypothesis is physically reasonable in the case of water movement through an
unsaturated soil.
76:02G-071
CAPILLARY HYSTERESIS AND THE RELATIONSHIP BETWEEN DRYING AND WETTING CURVES,
Parlange, J.-Y.
Connecticut Agricultural Experiment Station, New Haven, Connecticut.
Water Resources Research, Vol. 12, No. 2, p 224-228, April 1976. 5 fig, 24 ref.
Descriptors: *Hysteresis, *Soil moisture, *Mathematical models, Theoretical
analysis, Equations, Wetting, Drying, Pore water, Capillary action. Pores,
Groundwater potential, Air-water interfaces, Boundary processes, Saturation,
Sands, Silts, Loam, Soils, Microenvironment, Infiltration.
A simple microscopic model predicted the wetting and drying scanning curves from
only one boundary of the main hysteresis loop. Comparison with experiments
showed that if the shape of the drying scanning curves varies smoothly, then the
drying boundary of the loop is indeed sufficient to predict all scanning curves.
However, if the shape of the drying curves changes abruptly, the model is still
applicable, but the drying boundary yields only the wetting scanning curves, and
the wetting boundary yields only the drying scanning curves. For this case the
model seems more reliable for predicting the scanning curves than for the appli-
cation of interpolation techniques between the two boundaries.
76:02G-072
APPROXIMATIONS FOR VERTICAL INFILTRATION RATE PATTERNS,
Smith, R.E.
Agricultural Research Service, Southwest Watershed Research Center, Tucson,
Arizona.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 505-509, May-June 1976. 3 fig, 19 ref.
Descriptors: *Infiltration, *Soil physics, *Infiltration rates, *Unsaturated
flow, *Soil water movement, Soils, Porous media, Equations, Soil properties.
Mathematical models. Unsteady flow, Computer models. Model studies.
The need for description of the time-varying rate of infiltration into soils led
to the development of empirical formulas before the physics of fluid flow in
porous media provided theoretical tools for analysis of this aspect of unsatur-
ated soil water movement. Selected contributions toward a usable description
of the surface-soil infiltration rate for two boundary and initial conditions
were reviewed. The approximations ranged from simple formulas to complex models
developed from computer analysis of Richards' equation. The tradeoffs in number
of parameters and accuracy were discussed for several infiltration models.
76:02G-073
SOIL WATER MODELING I. A GENERALIZED SIMULATOR OF STEADY, TWO-DIMENSIONAL FLOW,
Amerman, C.R.
Agricultural Research Service, North Central Region Watershed Research Center,
Columbia, Missouri.
Transactions of the American Society of Agricultural Engineers, Vol.19, No. 3,
p 466-470, May-June 1976. 6 fig, 21 ref.
Descriptors: *Soil water, *Model studies, *Computer models, *Soil water move-
ment, Boundaries (Surfaces), Hydraulic conductivity, Pressure head. Numerical
analysis, Darcy's Law, Unsaturated flow,- Equations, Porous media, Theoretical
analysis, Steady flow.
A computational scheme was developed for solving the steady-state, two-dimension-
al form of Richard's equation using finite differencing. The successive over-
relaxation method was used. The computer model developed for implementing the
computational scheme was generalized using a technique called subsectioning,
which allows application of the model, without internal modification, to a wide
60
-------
range of geometric shapes, hydraulic boundary conditions, and soil distributions
Unsaturated or saturated flow regions or those containing phreatic surfaces may
be modeled. The nonlinear nature of Richard's equation was reflected in the
overrelaxation coefficient which had a maximum rather than an optimum value.
Values higher than maximum caused instability.
76:02G-074
CALCULATING THE UNSATURATED HYDRAULIC CONDUCTIVITY AND DIFFUSIVITY,
Whisler, F. D.
Mississippi State University, Department of Agronomy, State College, Mississippi.
Soil Science Society of America Journal, Vol. 40, No. 1, p 150-151, January-
February 1976. 2 fig, 7 ref.
Descriptors: *Unsaturated flow, *Hydraulic conductivity, *Diffusivity, *Moisture
content, *Pressure head, Numerical analysis, Equations, Soil water movement, Soil
water, Graphical analysis. Methodology, Soil properties.
The methods of R. D. Jackson and R. H. Brooks and A. T. Corey for calculating the
unsaturated hydraulic conductivity from water content-pressure head relationships
were compared. The corresponding diffusivity relationships can also be evaluated
either by a numerical differentiation of the water content-pressure head curves
plus the conductivity, or by direct calculation from the differentiation of the
Brooks and Corey function. Both methods gave approximately the same results for
the hydraulic conductivity relationships. The diffusivity values calculated from
the Brooks and Corey functions were lower than those calculated by the numerical
method for a Grenada silt loam soil. Both diffusivity relationships gave essen-
tially the same beta values for the W. E. Gardner and M. S. Mayhugh diffusivity-
water content function.
76:02G-075
PLANT WATER STRESS CRITERIA FOR IRRIGATION SCHEDULING,
Stegman, E.G., Schiele, L.H., and Baure, A.
North Dakota State University, Department of Agricultural Engineering, Fargo,
North Dakota.
Presented at the 1975 Winter Meeting of the American Society of Agricultural
Engineers, December 15-18, 1975, Chicago, Illinois. 22 p, 7 fig, 6 tab, 18 ref.
ASAE Paper 75-2555.
Descriptors: *Soil water, *Soil moisture, *Soil-water-plant relationships,
*Scheduling, Crop response, Plant physiology. Plant tissues, Irrigation,
Irrigation effects.
This study was conducted to determine the potential for relating plant water
stress development to variables indicative of prevailing soil and atmospheric-
environments. Given such relationships irrigation scheduling services should be
better able to use plant stress oriented criteria for determining when to irri-
gate. Stress development was evaluated by leaf xylem pressure and stomatal
diffusion resistance measurements. Data sets were obtained for 4 to 5 crops at
two Irrigation Branch Stations in North Dakota. The two sites provided soil
types with differing hydraulic properties and available water holding capacities.
Leaf xylem pressure data for each crop-soil combination were correlated by
regression procedures with ambient air temperatures and root zone soil moisture
content. Subsequent application of these xylem pressure levels as critical
limits to each regression model permitted estimation of allowable root zone
soil moisture depletion relative to expected ambient air temperatures. This
procedure offers a method for interpreting water balance estimates of soil
moisture deficit and advance forecasts of daily maximum air temperatures for
need of irrigation.
76:026-076
FIELD AND LABORATORY EVALUATION OF BI-LEVEL DRAINAGE THEORY,
Chu, S.T., and DeBoer, D.W.
South Dakota State University, Department of Agricultural Engineering, Brookings,
South Dakota.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 478-481, May-June 1976. 5 fig, 6 tab, 9 ref.
61
-------
Descriptors: *Drainage systems, *Theoretical analysis, *0n-site tests, *Labora-
tory tests, Water table, Water levels, Hydraulic conductivity. Porosity, Drains,
Data collections. Depth, Graphical analysis, Groundwater movement, Aquifers,
Viscosity.
Field and laboratory evaluations of a proposed bi-level drainage (system in
which drains are at two different depths on an alternating basis) theory were
presented. Graphical comparisons were made between the fall of the water table
as predicted by theory and as measured both in the field and in a Hele-Shaw
model. In both cases the agreement was good, indicating that the theory is an
adequate model to describe the water table fall.
76:020-077
UPWARD WATER MOVEMENT IN FIELD CORES,
Wells, L.G., and Skaggs, R.W.
Kentucky University, Department of Agricultural Engineering, Lexington, Kentucky.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 2,
p 275-283, March-April 1976. 12 fig, 3 tab, 29 ref.
Descriptors: *Groundwater movement, *Subsurface irrigation, *Cores, *Model
studies, Laboratory tests, Theoretical analysis, Hydraulic properties, Soil
properties, Soil profiles, Soil water movement. Design, Water table, Equations,
Irrigation, Pressure head, Moisture content, Boundaries (Surface, Tensiometers,
Hydraulic gradient, Hysteresis.
Subirrigation experiments were conducted under various initial and boundary
conditions using large, undisturbed cores from two field soils. The pressure
head distribution and flow volume were measured continuously, and the desorp-
tion and imbibition character of the soil water were determined using pressure
plates. The effect of air entrapment on water content was determined gravimet-
rically, while the hydraulic conductivity-pressure head relationship was deter-
mined for each soil from transient pressure head measurements during a drainage
event. An approximate model was developed to describe vertical water movement
during subirrigation. This model as well as the Richards' equation were tested
against experimental results from both soils. Substantial variability was evi-
dent in both measured soil properties and in water movement phenomena. The
approximate subirrigation model provided acceptable agreement with the observa-
tions. Consideration of soil stratification generally improved model accuracy.
For engineering design the added time and expense of sophisticated models are
not justified in comparison to the approximate model. Determination of the
total volume of stored water in a profile under specified boundary conditions
is essential to predictions of water movement.
76:02G-078
SURFACE RESIDUE, WATER APPLICATION, AND SOIL TEXTURE EFFECTS ON WATER ACCUMULA-
TION,
Unger, P-W.
Agricultural Research Service, Bushland, Texas, and Southwestern Great Plains
Research Center, Bushland, Texas.
Soil Science Society of America Journal, Vol. 40, No. 2, p 2980300, March-April
1976. 2 fig, 14 ref.
Descriptors: *Soil water, *Farm management, *Water storage, *Great Plains,
*0rganic matter, Mulching, Soils, Loam, Clay loam, Evaporation, Precipitation
(Atmospheric), Irrigation, Crops, Wheat, Soil properties. Soil science.
Surface residue rates and water application amounts affect evaporation from soil.
These factors were evaluated for their effects on water accumulation in a clay
loam and a fine sandy loam soil. Surface residue rates ranged from 0 to 12,000
kg/ha and water was added at 0.25, 0.5, 1.0, or 2.0 cm/addition. At low residue
rates and water applications, little or no water accumulated in the soils. The
amount of water that accumulated in the soils increased as surface residue rates
and water applications increased. Results for the two soils were remarkably
similar, apparently because the liquid and vapor flow characteristics for the
two soils were similar at high water contents, even though their water retention
characteristics differed markedly. The results of this laboratory study were
62
-------
discussed with regard to residue management practices for low (dryland) and
high (irrigated) residue production systems of the Great Plains.
76:02G-079
VARIABILITY OF HYDRAULIC CONDUCTIVITY IN TWO SUBSURFACE HORIZONS OF TWO SILT
LOAM SOILS,
Baker, F.G., and Bouma, J.
Wisconsin University, Department of Soil Science, Madison, Wisconsin.
Soil Science Society of America Journal, Vol. 40, No. 2, p 219-222, March-April
1976. 3 fig, 10 ref. EPA R802874.
Descriptors: *Hydraulic conductivity, *Soils, *Soil properties, Variability,
Loam, Loess, Silts, Subsoil, Soil horizons, Soil investigations, Infiltration,
Groundwater, Groundwater potential. Soil moisture, Soil water movement, Soil
science.
Hydraulic conductivity was measured in the B22t and B31t horizons of 12 pedons
of two soils developed in loess deposits overlying glacial till. Conductivity
measurements were made with the crust test technique for unsaturated conditions
and with a new related in situ method for saturated conditions. Nonlinear
regression yielded simple well-fitting curves. Variability within and between
major horizons in these soil series was found to be relatively low. The four
horizons in these two silt loam soils had statistically identical hydraulic
conductivity characteristics, even though morphological soil structure and soil
genesis differed significantly.
76:02G-080
DETERMINING THE HYDRAULIC CONDUCTIVITY OF SOIL CORES BY CENTRIFUGATION,
Alemi, M.H., Nielsen, D.R., and Biggar, J.W.
California University.- Department of Land, Air and Water Resources, Davis,
California.
Soil Science Society of America Journal, Vol. 40, No. 2, p 212-318, March-April
1976. 5 fig, 2 tab, 15 ref, 1 append.
Descriptors: *Hydraulic conductivity, *Soils, *Centrifugation, *Infiltration,
Laboratory tests, Groundwater movement, Permeability, Diffusivity, Conductivity,
Hydrologic properties, Soil water. Soil moisture, Moisture content, Soil prop-
erties. .
Two centrifugal techniques were proposed for determining the hydraulic conductiv-
ity of cores of natural soil. Experimental results were presented for one
technique in which the change in weight of one end of the sample, previously
centrifugated, was measured with a balance. The mathematical equations describ-
ing this redistribution process were developed and fitted to the data to ascer-
tain the soil water diffusivity D. The value of the hydraulic conductivity K
was obtained from K - bD, where b is also calculated. Calculated values of K
agreed with previously published values. The second technique for which a
theory was presented but no experimental values were provided depends upon the
measurement of the volumetric outflow of water from a soil core when the speed
of centrifugation is suddenly increased.
76:02G-081
DRAINAGE SYSTEM EFFECTS ON PHYSICAL PROPERTIES OF A LAKEBED CLAY SOIL,
Hundal, S.S., Schwab, G.O., and Taylor, G.S.
Ohio State University, Department of Agronomy, Columbus, Ohio.
Soil Science Society of America Journal, Vol. 40, No. 2, p 300-305, March-April
1976. 7 fig, 1 tab, 11 ref.
Descriptors: *Drainage effects, *Crop response, *Soil properties, Drainage,
Drainage practices. Soils, Soil physical properties. Soil strength, Compressive
strength, Soil texture, Pores, Proosity, Land management, Surface drainage,
Subsurface drainage. Hydraulic conductivity, Agriculture.
The long-term effects of drainage on physical properties of a lakebed silty clay
soil were evaluated 16 years after initiation of a field experiment. The
63
-------
treatments were undrained, surface drainage, subsurface drainage, and a combin-
ation of surface and subsurface drainage. Soil conditions were characterized by
surface penetration resistance and by unconfined compressive strength, hydraulic
conductivity, and pore size distribution in the 0-30 cm depth. Subsurface
drainage resulted in greater soil hydraulic conductivity, less unconfined com-
pressive strength, and less surface crust resistance than treatments without
subsurface drainage. Subsurface drainage also decreased bulk density and in-
creased the volume of air-filled pores at 0.02 to 1.0-bar suctions, but these
effects were of smaller magnitude. An alfalfa-timothy mixture was grown during
the period of these measurements. The survival of alfalfa and the total hay
yield decreased in the order: combined surface and subsurface drained, surface
drained, and undrained treatments.
76:02G-082
VERTICAL FLOW OF AIR AND WATER WITH A FLUX BOUNDARY CONDITION,
McWhorter, D.B.
Colorado State University, Department of Agricultural Engineering, Fort Collins,
Colorado.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 2,
p 259-265, March-April 1976. 3 fig, 1 tab, 7 ref.
Descriptors: *Soil water movement, *Air-water interfaces, *Infiltration, Air,
Viscosity, Compressibility, Equations, Darcy's Law, Permeability, Saturation,
Density, Pore pressure, Atmospheric pressure, Water pressure, Hydraulic con-
ductivity, Porosity, Boundaries (Surfaces), Soil properties, Continuity equa-
tion, Ponding, Approximation method, Graphical methods.
The effects of viscous resistance to air flow in the downward movement of infil-
trating water in soil were analyzed. A conceptual model was used in which air
was replaced by a hypothetical incompressible fluid with a viscosity equal to
that of air. An equation analogous to Darcy's Law was derived which incorpor-
ated resistance to flow of both air and water. The flow equation was later
transformed to a dimensionless form. An important assumption used in deriving
the equation was that the volume flux of the air is everywhere equal to and
opposite in direction to that of water. An approximate solution was obtained
using Parlange's technique of successive approximation, and the range of appli-
cability for the solution was determined graphically. Numerical examples were
presented which indicated that resistance to flow of an incompressible fluid
with a viscosity equal to that of air would significantly influence both pond-
ing time and the maximum infiltration rate short of ponding. Apparently the
actual time-to-ponding must be between the two extremes predicted by single-
phase and two-phase incompressible flow theory.
76:02G-083
HYDRAULIC PROPERTIES OF A POROUS MEDIUM: MEASUREMENT AND EMPIRICAL REPRESENTATION,
Gillham, R.W., Klute, A., and Heermann, D.F.
Waterloo University, Department of Earth Sciences, Ontario, Canada.
Soil Science Society of America Journal, Vol. 40, No. 2, p 203-207, March-April
1976, 6 fig, 3 tab, 16 ref.
Descriptors: *Hydraulic properties, *Soil water.- *Hysteresis, *Porous media,
Laboratory tests, Soil moisture, Moisture content, Soil water movement, Ground-
water movement. Infiltration, Drainage, Evaporation, Soil moisture meters, Hydro-
static pressure, Pressure head. Wetting, Drying, Soils.
The hysteretic water content-pressure head relationship and the hydraulic conduc-
tivity-water content relationship for a porous material are needed in the solution
of the water flow equation to predict behavior of a given flow system. These
hydraulic properties were measured in an unsteady-state manner using gamma ray
attenuation for the water content and strain gage pressure transducer tensiometry
for the pressure head. Envelope curves and four to six primary wetting and dry-
ing scanning curves of the water content-pressure relationship were determined.
A convenient method of representation of the scanning curves by an empirical
function was developed for use in computer solutions of the water flow equation.
64
-------
76:02G-084
SPATIAL VARIABILITY OF THE LEACHING CHARACTERISTICS OF A FIELD SOIL,
Bigger, J.W., and Nielson, D.R.
California University, Department of Land, Air and Water Resources, Davis,
California.
Water Resources Research, Vol. 12, No. 1, p 78-84, February 1976 10 fiq
3 tab, 14 ref.
Descriptors: *Spatial distribution, *Leaching, *Soils, *Soil profiles, Salts,
Pore water, Solutes, Infiltration, Diffusion, Sampling, Infiltration rates,
On-site investigations, Soil water.
Solute distributions within a soil profile during the leaching of water-
soluble salts applied to the soil surface were measured at six depths to
182.4 cm within 20 subplots of a 150,hectare field. Estimates of the pore
water velocity based upon measures of solute displacement within each
subplot and the entire field were found to be logarithmically normally
distributed and in agreement with the volumetric measures of water
infiltration rates. Such agreement was possible only because it was
recognized that the observed values were not normally distributed and
their mean values were calculated accordingly- The number of observations
required to yield an estimate of the mean pore water velocity within
a prescribed accuracy was shown to depend upon the nautre and extent
of the spatial variability of the field soil. For the field examined, 100
observations allowed the mean pore water velocity to be estimated within
+ or - 50 percent of its true value. The functional relation between
field-measured values of the apparent diffusion coefficient, also found
to be logarithmically normally distributed, and pore water velocity was
examined and interpreted in terms of solute distributions likely to
be measured at specific sampling sites.
76:020-085
INFILTRATION ANALYSIS AND PERTURBATION METHODS I. ABSORPTION WITH EXPONENTIAL
DIFFUSIVITY,
Babu, D.K.
City College, Department of Mathematics, New York, New York.
Water Resources Research, vol. 12, No. 1, p 89-93, February 1976. 1 fig,
25 ref.
Descriptors: *Soil moisture, *Infiltration, *Model studies, *Absorption,
Mathematical models. Equations, Analytical techniques. Subsurface waters,
Diffusion, Soil temperature, Soil physical properties, Soils, Diffusivity.
Simple perturbation methods were employed to analyze the horizontal absorption
of moisture in unsaturated soils. The special case treated assumed the
diffusivity to be an exponential function of the concentration and the con-
centration at the boundaries to be constant. The solution emerged as an
explicitly determined power series in the Boltzmann variable. The resulting
profiles were compared with some others found in the existing literature.
A discussion about the relevance and advantages of this type of analysis
formed the concluding part of the paper.
76:02G-086
DIFFUSION AND MASS FLOW OF NITRATE-NITROGEN TO PLANT ROOTS,
Phillips, R.E., NaNagara, T., Zartman, R.E., and Leggett, J.E.
Kentucky Agricultural Experiment Station, Department of Agronomy, Lexington,
Kentucky.
Agronomy Journal, Vol. 68, No. 1, p 63-68, January-February 1976. 2 fig,
1 tab, 11 ref.
Descriptors: *Soil-water-plant relationships, *Diffusion, *Soil water move-
ment, *Nitrogen, *Nitrates, *Root systems. Transpiration, Nutrient requirements,
65
-------
Model studies, Flow Moisture content. Absorption, Model studies, Path of
pollutants, Corn (Field).
A model for estimating nitrate-nitrogen uptake by plant roots is developed
and its application discussed. Soil and plant parameters which must be
known in order to predict transport by diffusion and mass flow include volu-
metric soil water content, N03-N concentration in soil solution, porous
diffusion coefficient of soil N03-N, average soil water macroscopic velocity
at the plant root surface, root radius, transpiration rate and plant root
length. A previously reported steady-state model for simultaneous mass
flow and diffusion is evaluated with reference to measurement of those para-
meters. The importance of diffusion to mass flow is great when the ratio
of transpiration rate to the constant of proportionality relating flux into
the plant to N03-N concentration in soil solution is less than 0.2.
76:02G-087
INFILTRATION INTO INCREASINGLY PERMEABLE SOILS,
Bouwer, H.
Agricultural Research Service, Water Conservation Laboratory, Phoenix,
Arizona.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 102, No. IR1, Proceedings Paper 11959, p 127-136, Marc.h
1976. 3 fig, 1 tab, 9 ref.
Descriptors: *Drainage, *Infiltration, *Infiltration rates, *Permeability,
Soil properties, Soils, Digital computers, Irrigation, Hydraulic conduc-
tivity, Equations, Wetting, Depth.
A tabular procedure, based on the Green-Ampt equation, was developed to
calculate infiltration into soil that becomes more permeable with depth. The
procedure is simple and the results compared favorably with those obtained
with a digital computer. The procedure supplements a previous paper which
showed how the Green-Ampt equation could be used to calculate infiltration
into soil becoming less permeable with depth. The Green-Ampt equation is
emerging as a useful, simple, yet theoretically sound infiltration equation.
The extension of the equation to soils where the permeability changes with
depth should enhance its utility in practical applications, where soils are
seldom, if ever, uniform.
76:02G-088
ON THE STOCHASTIC FOUNDATIONS OF THE THEORY OF WATER FLOW THROUGH UNSATURATED
SOIL,
Bhattacharya, R., Gupta, V-, and Sposito, G,
Arizona University, Department of Mathematics, Tucson, Arizona,
Water Resources Research, Vol. 12, No, 3, June 1976. 40 ref.
Descriptors: *Hydraulic conductivity, Diffusivity, *Soil water movement,
Stochastic processes, *Unsaturated flow.- *Markov processes, Equations, Soil
moisture.
The parabolic differential equation that describes the isothermal isohaline
transport of water through an unsaturated soil is shown to be the mathematically
rigorous result of a fundamental stochastic hypothesis: that the trajectory
of a water molecule is a nonhomogeneous Markov process characterized by space-
and-time-dependent coefficients of drift and diffusion. The demonstration is
valid in general for heterogeneous anisotropic soils and provides for three
principal results in the theory of water flow through unsaturated media: (1)
a derivation of the Buckingham-Darcy flux law that does not rely directly on
experiment, (2) a new theoretical interpretation of the soil water diffusivity
66
-------
and the hydraulic conductivity in molecular terms, and (3) a proof that the soil
is a symmetric tensor of the second rank. A dynamic argument at the molecular
level is developed to show that the fundamental Markovian hypothesis is physi-
cally reasonable in the case of water movement through an unsaturated soil.
76:02G-089
WETTING FRONT PRESSURE HEAD IN THE INFILTRATION MODEL OF GREEN AND AMPT,
Neuman, S.P.
Arizona University, Department of Hydrology and Water Resources, Tucson, Arizona.
Water Resources Research, Vol. 12, No. 3, p 564-566, June 1976. 22 ref.
Descriptors: *Soil water movement, *Model studies, Mathematical studies,
*lnfiltration, *Pore pressure, *Pressure head, *Air circulation, Wetting, Water
pressure, Seepage, Soil properties, Time, Gravitational water sorption, Unsat-
urated flow. Equations.
A theoretical expression relating the wetting front pressure head in the infil-
tration model of Green and Ampt to soil characteristics was derived. This
expression was identical to that previously suggested by Bouwer on the basis of
an analogy with horizontal flow. It differed from a more complete expression
recently proposed by Morel-Seytoux and Khanji in that the effect of air mobil-
ity was neglected, the need for determining the functional relationship between
the relative permeability of air and water saturation thus being avoided.
76:02G-090
A NEW MODEL FOR PREDICTING THE HYDRAULIC CONDUCTIVITY OF UNSATURATED POROUS
MEDIA,
Mualem, Y.
Technion-Israel Institute of Technology, Department of Civil Engineering, Haifa,
Israel.
Water Resources Research, Vol. 12, No. 3, p 513-522, June 1976. 4 fig, 3 tab,
34 ref, 3 append. U.S.-ISBF 422.
Descriptors: *Unsaturated flow, *Hydraulic conductivity, *Mathematical models,
*Porous media. Moisture content, Pore pressure, Saturation, Theoretical analysis,
Soil properties, Homogeneity, Porosity, Capillary conductivity, Soil types,
Model studies. Equations, Mathematical studies.
A simple analytic model was proposed which predicts the unsaturated hydraulic
conductivity curves by using the moisture content-capillary head curve and the
measured value of the hydraulic conductivity at saturation. It was similar to
the Childs and Collis-George (1950) model but used a modified assumption con-
cerning the hydraulic conductivity of the pore sequence in order to take into
account the effect of the larger pore selection. A computational method was
derived for the determination of the residual water content and for the extrap-
olation of the water content-capillary head curve as measured in a limited
range. The proposed model was compared with the existing practical models of
Averjanov (1950), Wyllie and Gardner (1958) , and Millington and Quirk (1961) on
the basis of the measured data of 45 soils. It seemed that the new model is
in better agreement with observations.
76:02G-091
ANALYTICAL SOLUTION OF THE EQUATION FOR TRANSPORT OF REACTIVE SOLUTES THROUGH
SOILS,
Selim, H.M., and Mansell, R.S.
Florida University, Department of Soil Science, Gainesville, Florida.
Water Resources Research, Vol. 12, No. 3, p 528-532, June 1976. 3 fig, 18 ref.
OWRT A-026-FLA(8).
Descriptors: *Soil water movement, *Solutes, *Analytical techniques, *Soil
chemistry, *Leachate, *Adsorption, Aqueous solutions, Soils, Steady flow, Infil-
tration, Unsteady flow, Laboratory tests, Equations, Mathematical studies, Soil
surfaces.
Mathematical solutions of the differential equation governing reactive solute
67
-------
transport in a finite soil column were developed for two specific cases:
continuous solute input and pulse-type solute input at the soil surface.
These solutions incorporated reversible linear adsorption as well as irriver-
sible solute adsorption. The irreversible adsorption was expressed by a sink/
source term which either may be a constant or may have a concentration-dependent
form. The boundary condition used across the surface was that of the third
type, which accounted for advection as well as dispersion. To illustrate
the significance of using the proper boundary conditions, comparisons were
made with two other mathematical solutions. It was concluded that the solution
presented was highly useful for low pore flow velocities. For large pore velo-
cities, all three solutions were in agreement.
76:02G-092
WATER TRANSPORT IN THE SOIL-ROOT SYSTEM: TRANSIENT ANALYSIS,
Molz, P.J.
Auburn University, Department of Civil Engineering, Auburn, Alabama.
Water Resources Research, Vol. 12, No. 4, p 805-808, August 1976. 2 fig, 27
ref.
Descriptors: *Soil water movement, *Root zone, *Root systems, *Equations, Soils,
Unsteady flow, Potential flow, Numerical analysis, Hydraulic gradient, Available
water, Mathematical models, Theoretical analysis, Boundaries (Surfaces), Xylem,
Plant tissues, Hydraulic conductivity, Laboratory tests.
Equations were developed which describe the transient flow of water in a cylin-
drical soil-root system. The main objective was to calculate water potential
distributions in the root cortex as well as in the surrounding soil. Numerical
results indicated that there will be small water potential gradients in the soil
relative to those in the root in the upper 90% of the water availability range.
Contrary to past experiments, theory predicted that appreciable amounts of water
should flow from roots to soil when roots well supplied with water are in con-
tact with dry soil. An important implication of the study was that models
designed to predict the pattern in which roots extract water from soil will
have to consider the rate-limiting aspect of the root tissue.
76:02G-093
THE APPLICATION OF THE OVERBURDEN POTENTIAL THEORY TO SWELLING SOILS,
Towner, G.D.
Agricultural Research Council, Unit of Soil Physics, Cambridge, England.
Water Resources Research, Vol. 12, No. 6, p 1313-1314, December 1976. 2 fig,
8 ref.
Descriptors: *Soil water, *Soils, *Hysteresis, Soil moisture, Moistur-e content,
Physical properties, Pore water, Shrinkage, Mathematical models. Water table,
Soil science.
From a consideration of alternative loading paths in the shrinkage diagram of
swelling soils, it was shown that hysteresis in the relationship between the
voids ratio and the moisture ratio may occur, even though no actual reversals
of loading have been allowed nor any irreversible structural changes have taken
place. Therefore, it was argued that the application of the overburden poten-
tial theory to the analysis of situations, such as water profiles above water
tables in vertical soil columns, is questionable. The need for experimental
studies was stressed.
76:020-094
A COMPARISON OF TECHNIQUES FOR SOLVING THE DIFFUSION EQUATION WITH AN EXPONEN-
TIAL DIFFUSIVITY,
Parlange, J.-Y., and Babu, O.K.
Connecticut Agricultural Experiment Station, New Haven, Connecticut.
Water Resources Research, Vol. 12, No. 6, p 1317-1318, December 1976. 8 ref.
Descriptors: *Diffusion, *Diffusivity, *Mathematical studies, Equations, Soil
water, Sorption.
A recent solution obtained by Babu when the soil water diffusivity has an expo-
68
-------
nential behavior was compared with two earlier solutions. It was shown that
with a slight modification, Babu's perturbation solution is identical to the
iterative solution using Cisler's correction. it was also shown that solutions
which optimize the sorptivity and the front position are numerically indistin-
guishable from either the perturbation or the iterative solution but have, in
general, a much simpler analytical form.
76:02G-095
ON SOLVING THE INFILTRATION EQUATION—A COMPARISON OF PERTURBATION AND ITERATIVE
TECHNIQUES,
Parlange, J.-Y., and Babu, O.K.
Connecticut Agricultural Experiment Station, New Haven, Connecticut.
Water Resources Research, Vol. 12, No. 6, p 1315-1316, December 1976. 10 ref.
Descriptors: *Infiltration, *Gravity, *Diffusivity, Mathematical model's. Analyti-
cal techniques, Soils, Equations, Soil water, Moisture content, Soil moisture,
Soil water movement, Soil science.
A recent solution obtained by Babu following a perturbation method was compared
with an earlier iterative method. It was shown that after improvement, Babu's
perturbation solution becomes identical to the iterative solution using Cisler's
correction. A simpler solution based on an optimal scheme was also presented.
76-.02G-096
ASSESSMENT OF AVAILABLE WATER STORAGE CAPACITY OF SOILS WITH RESTRICTED SUBSOIL
PERMEABILITY,
McCown, R.L., Murtha, G.G., and Smith, G.D.
Commonwealth Scientific and Industrial Research Organization, Division of
Tropical Crops and Pastures, Townsville, Australia.
Water Resources Research, Vol. 12, No. 6, p 1255-1259, December 1976. 3 fig,
25 ref.
Descriptors: *Storage capacity, *Soil water, *Soil moisture, *Root zone,
*Permeability, Soils, Water Storage, Tropical regions, On-site investigations.
Sampling, Ponding, Subsoil, Soil water movement. Soil horizons, Soil science.
The pasture production of most of the tropics is largely a function of the water
regime. One of the few options for control of the water regime in these environ-
ments is choice of site. A site parameter of great importance is the ax'ailable
water storage capacity (AWSC) in the root zone. Although estimation of the AWSC
is straight-forward on freely drained soils, it is complicated on poorly drained
soils by the inapplicability of the concept of field capacity. The latter soils,
however, commonly have a buildup of salts at depth in the profile, presumably
due to prevailing leaching conditions. The study reported herein was conducted
to test the hypothesis that this salt profile can be used to indicate the depth
of wetting under conditions similar to those producing maximum subsoil water
recharge in this climate. Twenty sites on mainly texture contrast soils, most
with poorly drained subsoils, were examined in detail. A close relationship
between the observed depth of wetting and the depth to the salt bulge was
found. This relationship, together with the total porosity of the top (wettest)
stratum of the B horizon, provides a means of estimating the AWSC of the sub-
soil.
76:026-097
HYSTERETICAL MODELS FOR PREDICTION OF THE HYDRAULIC CONDUCTIVITY OF UNSATURATED
POROUS MEDIA,
Mualem, Y.
Colorado State University, Engineering Research Center, Fort Collins, Colorado.
Water Resources Research, Vol. 12, No. 6, p 1248-1254, December 1976. 12 fig,
12 ref, 1 append. NSF ENG-7611542.
Descriptors: *Hysteresis, *Hydraulic conductivity, *Model studies. Mathematical
models, Moisture content, Capillary conductivity. Porous media, Unsaturated
flow, Groundwater, Soil water. Pore pressure, Pore water, Soil science.
A theory which permits a quantitative prediction of the actual phenomena of con-
69
-------
siderable hysteresis characterizing the hydraulic conductivity-capillary head
relationships, and the less significant hydraulic conductivity-moisture content
hysteresis, was proposed. The models used to represent capillary hysteresis
were extended to permit the prediction of the hydraulic conductivity of un-
saturated porous media for any continuous process of imbibition and drainage.
The generalized models require the same amount of experimental data as the
previous models, with the addition of a measured value of the hydraulic con-
ductivity at a definite point. For an incompleter measured theta (psi) loop,
the knowledge of K at the minimum measured value of psi can be used to improve
prediction. The dependent domain model suggested by Mualem and Dagan was
generalized by adding two functions, KL(psi) and KH(psi). All K(psi) scanning
curves were expressed with the aid of KL(psi) and KH(psi) by convenient compact
formulation similar to that used to describe the theta (psi) curves. Very
good agreement between theory and observations was found. The predicted K(psi)
hysteresis has all the experimentally observed features. The predicted K(theta)
hysteretical loop almost shrinks to a unique curve, though the psi(theta) loop,
used as data, is of considerable extent.
76:020-098
A PERTURBATION SOLUTION FOR A NON-LINEAR DIFFUSION EQUATION,
Liu, P.L.-F.
Cornell University, School of Civil and Environmental Engineering, Ithaca,
New York.
Water Resources Research, Vol. 12, No. 6, p 1235-1240, December 1976. 2 fig,
2 tab, 17 ref. NSF ENG76-09421.
Descriptors: *Diffusion, *Soil water, *Mathematical models, Equations, Sorption,
Boundaries (Surfaces), Diffusivity, Mathematics, Analytical techniques.
Nonlinear diffusion problems with a constant boundary condition were investigated.
The concept of diffusion front was utilized to develop a perturbation solution.
Results were presented for two specific diffusivities which are functions of the
concentrations. The present technique was shown to be efficient and accurate.
76:020-099
THE CONCISE FORMULATION OF DIFFUSIVE SORPTION OF WATER IN A DRY SOIL,
Brutsaert, W.
Cornell University, School of Civil and Environmental Engineering, Ithaca,
New York.
Water Resources Research, Vol. 12, No. 6, p 1118-1124, December 1976. 1 tab,
38 ref.
Descriptors: *Sorption, *Soil water, *lnfiltration, *Model studies, Mathematical
models. Soils, Soil moisture. Moisture content, Soil moisture movement. Diffu-
sion, Equations, Diffusivity, Wetting, Mathematical studies, Soil science.
Several formulations for the sorption of water in a dry soil obtained on the
basis of approximate solution of the nonlinear diffusion were considered, and
their relative merits were investigeted. In addition, new solutions were devel-
oped by the application of a simple weighting of the available approximations.
In a comparison with one of Philip's exact solutions, it was found that the
error involved in all these solutions is, at most, of the order of 3 or 4%;
however, Parlange's optimization result and the weighting solutions appear to
be accurate to within a few thousandths. The sorptivity and the position of
the wetting front can be expressed consisely as functions of soil physical
parameters by applying either the two-parameter exponential diffusivity of
Gardner and Mayhugh or the three-parameter power function diffusivity of the
author. The mathematical form suggests that on a field or basinwide scale, the
sorptivity of the surface soil is log normally distributed.
76:020-100
INFILTRATION ANALYSIS AND PERTURBATION METHODS III. VERTICAL INFILTRATION,
Babu, O.K.
City College, Department of Mathematics, New York.
Water Resources Research, Vol. 12, No. 5, p 1019-1024, October 1976. 3 fig,
1 tab, 7 ref.
70
-------
Descriptors: *Infiltration, *Mathematical studies, *Unsaturated flow. Moisture
content, Boundaries (Surfaces), Theoretical analysis, Equations,Velocity Dif-
fusivity, Permeability, Numerical analysis.
Simple perturbation methods continue to yield good results in the solution of
the problem of vertical infiltration of water into unsaturated soils The
initial approximation is valid for all times and gives useful information about
important flow characteristics. The required computations are always direct
and simple. Some numerical work pertaineng to Yolo light clay was presented to
exhibit the advantages, relevance, and simplicity of the present analysis com-
pared to other existing works on this topic.
76:02G-101
INFILTRATION ANALYSIS AND PERTURBATION METHODS II. HORIZONTAL ABSORPTION,
Babu, D. K.
City College, Department of Mathematics, New York.
Water Resources Research, Vol. 12, No. 5, p 1013-1018, October 1976. 1 fig,
1 tab, 12 ref, 1 append.
Descriptors: *Infiltration, ^Absorption, *Mathematical studies. Equations,
Theoretical analysis, Unsaturated flow, Diffusivity, Moisture content,
Boundaries (Surfaces).
Perturbation methods are employed to analyze the horizontal absorption of
moisture in unsaturated soils. The reported study applied to absorption under
the general diffusivity function, subject to constant boundary concentration.
The concept of the wetting front moving with a finite velocity played a funda-
mental role in this set of papers. The solution emerges as a series of terms
that can be explicitly calculated in terms of the integrals involving diffus-
ivity functions. The examples of exponential and constant diffusivity functions,
as well as the case of Yolo light clay, were computed to one or two terms to
exhibit the advantages over, and the good agreement with, other published data
of Parlange, Philip, etc. The method possesses great potential, and in a sub-
sequent paper the study of vertical infiltration will be presented by utilizing
the perturbation mechanism.
76:02G-102 ,
THE DIFFERENT FORMS OF MOISTURE PROFILE DEVELOPMENT DURING THE REDISTRIBUTION
OF SOIL WATER AFTER INFILTRATION,
Youngs, E.G., and Poulovassilis, A.
Agricultural Research Council, Unit of Soil Physics, Cambridge, England.
Water Resources Research, Vol. 12, No. 5, p 1007-1012, October 1976. 7 fig,
18 ref.
Descriptors: *Infiltration, *Soil water movement, *Model studies, Mathematical
models. Laboratory tests. Soil water. Soil moisture, Water spreading. Moisture
content, Soils, Equations, Porous media, Percolation, Pervious soils, Soil
physical properties.
Two different forms of moisture profile development may occur during the redis-
tribution of soil water after infiltration. In one, the profile shape continues
to be similar to that profile developed during the infiltration process, with a
fairly uniform water content region near the soil surface above a steep wetting
front; and the rate of redistribution is inversely related to the infiltration
depth. In the other, water drains from near the surface to appear as a step in
the moisture profile below the wetting front at the cessation of infiltration;
and the rate of redistribution is directly related to infiltration depth. Clas-
sical theory of soil water movement was shown to account for both forms of
moisture profile development, which depend on the moisture profile shape at the
cessation of infiltration and on the soil water properties of the porous'material.
Experimental results of moisture profile development in a sand column illus-
trated how different profile forms develop as the depth of infiltration is
increased and, by inclining the experimental column, how they depend on the
relative importance of the soil water pressure head gradients compared with that
of gravity.
71
-------
76:02G-103
EXTRACTION OF SOIL WATER USING CELLULOSE-ACETATE HOLLOW FIBERS,
Jackson, D.R., Brinkley, F.S., and Bondietti, E.A.
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Soil Science Society of America Journal, Vol. 40, No. 2, p 327-329, March-April
1976. 5 fig, 1 tab.
Descriptors: Soil water, Soils, Soil investigations, Soil properties, Soil
chemistry, Laboratory tests, Sampling, Greenhouses.
Cellulose-acetate hollow fibers were used to extract soil solutions from soil
columns. The fibers have unique characteristics of small diameter and high
flexibility and permeability which are ideally suited for use in soils. Two
experiments were completed to demonstrate the usefulness of the hollow fibers.
A 109Cd-tagged soil column was leached with distilled water, and subsequently
soil water was extracted with the fibers. The effective radius of soil-water
extraction by the fibers was evaluated. The results show that the fibers can
extract soil solution for chemical assay at moisture levels ranging from 20 to
50%. Applications of this technique include sampling soil solution from green-
house pots and experimental microcosms.
76:02G-104
COMPARISON OF FIVE KINETIC MODELS FOR ORTHOPHOSPHATE REACTIONS IN MINERAL SOILS,
Enfield, C.G., Harlin, C.C., and Bledsoe, B.E.
United States Environmental Protection Agency, Office of Research and Develop-
ment, Robert S. Kerr Environmental Research Laboratory, Ada, Oklahoma.
Soil Science Society of America Journal, Vol. 40, No. 2, p 243-249, March-April
1976. 3 fig, 2 tab, 31 ref.
Descriptors: Kinetics, Soils, Soil 'investigations, Soil properties. Soil chemi-
cal properties, Adsorption, Diffusion, Sorption.
The kinetics of orthophosphate sorption with 25 mineral soils have been experi-
mentally measured under laboratory conditions. The 25 mineral soils represent
a wide range of physical and chemical properties. Regression analyses have been
performed fitting the experimental data to five kinetic models. The five kinetic
models include: a linearized first-order sorption, a first-order Freundlich
sorption, an empirical function, a diffusion-limited Langmuir sorption, and a
diffusion-limited Freundlich sorption. Mean correlation coefficients of 0.81,
0.83, 0.84, 0.86, and 0.88 were obtained for the models, respectively.
76:02G-105
ESTIMATION OF COMPONENTS OF SOIL CATION EXCHANGE CAPACITY FROM MEASUREMENTS OF
SPECIFIC SURFACE AND ORGANIC MATTER,
Curtain, D., and Smillie, G.W.
University College, Department of Soil Science, Dublin, Ireland.
Soil Science Society of America Journal, Vol. 40, No. 3, p 461-462, May-June
1976. 3 tab, 14 ref.
Descriptors: *Cation exchange, Organic matter. Soil textures, Soils, Soil
properties, Soil investigations.
Cation exchange capacities of Irish soils developed from a wide range of parent
materials were found to be highly correlated with organic matter content and
specific surface but not with clay content. Multiple regression analysis showed
that organic matter in combination with specific surface accounted for 97% of the
variation in CEC whereas organic matter and clay content only accounted for 58%
of the variation. The better correlation between CEC and specific surface than
between CEC and clay content, is attributed to the ability of surface area meas-
urements to reflect the presence of phyllosilicates in silt and sand fractions"
of soils and to the fact that these minerals have less variable surface charge
densities than cation exchange capacities. It is proposed that specific surface
provides a better estimate than clay content, of the mineral component of CEC
for soils of varying mineralogy-
72
-------
76:02G-106
RELATION BETWEEN THE KINETICS OF NITROGEN TRANSFORMATION AND BIOMASS DISTRIBU-
TION IN A SOIL COLUMN DURING CONTINUOUS LEACHING,
Starr, J.L., and Parlange, J.-Y.
Connecticut Agricultural Experiment Station, New Haven, Connecticut.
Soil Science Society of America Journal, Vol. 40, Ho. 3, p 458-460,'May-June
1976. 1 fig, 5 ref.
Descriptors: Nitrogen, Leaching, Kinetics, Microorganisms, Soils Soil investi-
gations.
Nitrogen concentration profiles in soil columns with associated microbial
distributions have been used in the past to deduce the kinetics of nitrogen
transformations during steady leaching. Owing to the many factors which control
microbial reaction kinetics in continuous flow systems, the effect of biomass
variation and order of reaction cannot be separated by simply measuring steady-
state concentrations profiles. It is shown here that in practice these measure-
ments only lead to some average kinetics for the system observed, even when the
microbe distribution is measured independently- Previously published experi-
mental data in conjunction with a derived expression are used to illustrate the
point.
76:02G-107
POTASSIUM RELEASE FROM SAND, SILT, AND CLAY SOIL SEPARATES,
Munn, D.A., Wilding, L.P., and McLean, E.O.
North Carolina State University, Department of Soil Science, Raleigh, North
Carolina.
Soil Science Society of America Journal, Vol. 40, No. 3, p 364-366, May-June
1976. 6 tab, 10 ref.
Descriptors: Soils, Soil investigation, *Potassium, Soil texture, Soil proper-
ties. Soil chemistry. Nutrients, Soil chemical properties, Particle size.
Four Ohio soils of divergent mineralogy were fractionated into sand, silt, and
clay-sized separates after dispersion with an ultrasonic probe. Samples were
extracted for 10 days with 0.01M CaC12 with the solution being changed each day.
There was a wide range in daily and cumulative K release among the four soils
for the same particle size and for different particle sizes within the same
soil. When weighted according to particle size distribution of the soil, the
clay was found to contribute 30-74%; silt 24-56%; and sand 3-21% of the total
K released by the sum of the three separates. In all four soils, the clay
separate released the most K per unit weight. The apparent rate constants for
K release from the sand and clay separates were similar and generally higher
than that for the silt separates.
76.-02G-108
WATER CONTENT AND BULK DENSITY DURING WETTING OF A BENTONITE-SILT COLUMN,
Nofziger, D.L., and Swartzendruber, D.
Oklahoma State University, Department of Agronomy, Stillwater, Oklahoma.
Soil Science Society of America Journal, Vol. 40, No. 3, p 345-348, May-June.
1976. 6 fig, 14 ref.
Descriptors: *Soil moisture, Soil water, Bulk density, Soil water movement,
Soils, Soil properties, Clays, Seepage, Saturated flow, Unsaturated flow.
An improved method of dual-energy gamma-ray attenuation was used to measure
water content and bulk density rapidly and accurately, during one-dimensional,
unsaturated water movement into a column of an equal-part mixture of initially
air-dry, highly swelling bentonite and silt. The bulk density near the inlet
end of the column decreased rapidly as water entered. Since the ends of the
column were confined, the expansion of the wetted bentonite-silt produced a
compression in the remaining air-dry portion of the column. Several water-
content variables were plotted against the so-called reduced material coordi-
nate m/t(l/2) (Boltzmann variable expressed in terms of the material coordinate
m and time t) . Neither the volumetric water content not the volumetric water
ratio would coalesce the data when plotted against m/t(l/2). In contrast, a
plot of water saturation vs. m/t(l/2) did coalesce the data into a single curve,
73
-------
except for very early times at positions nearer than 1 cm to the water inlet.
76:020-109
DENITRIFICATION KINETICS IN SOIL SYSTEMS: THE SIGNIFICANCE OF GOOD FITS OF
DATA TO MATHEMATICAL FORMS,
Kohl, D.H., Vithayathil, F. , Whitlow, P-, Shearer, G., and Chien, S.H.
Washington University, Department of Biology.- Saint Louis, Missouri.
Soil Science Society of America Journal, Vol. 40, No. 2, p 249-253, March-April
1976. 5 fig, 10 ref.
Descriptors: Denitrification, Kinetics, Soils, Soil properties, Saturation.
The loss of N03(-) added to two central Illinois soils was determined in exper-
iments in which the soils were incubated under waterlogged conditions. The
loss was measured as a function of substrate concentration in one experiment in
which samples were incubated for a single time (24 hours) and as a function of
time in a second experiment in which the concentration of the added NO3(-) was
held constant (200 ppm N03(-)-N). The rate of loss of N03(-) was about 5.5
times higher in one of the soils than in the other. This difference was large-
ly overcome by the addition of glucose (1% with respect to the soil) which also
greatly enhanced the rate of denitrification in both soils. The experimental
points representing the rate of N03(-) loss plotted as a function of the con-
centration of added N03(-), were equally well fit by Michaelis-Menten and expo-
nential equations as well as by the solution to a pair of nonlinear differential
equations representing a system in which the product of one reaction is a sub-
strate in a second sequence.
76-.02G-110
THE RESISTANCE OF INTACT MAIZE ROOTS TO WATER FLOW,
So, H.B., Aylmore, L.A.G., and Quirk, J.P-
New England University, Department of Agronomy and Soil Science, Armidale, New
South Wales, Australia.
Soil Science Society of America Journal, Vol. 40, No. 2, p 222-225, March-April
1976. 2 fig, 3 tab, 9 ref.
Descriptors: Tensiometers, Maize, Root systems. Soil water, Soil water move-
ment.
Using a novel tensiometer-potometer system relationship between the root resis-
tance to water flow of maize and the water potential of the root tissue has
been examined. Over the range of water potentials used, a linear relation has
been observed in contrast to previous observations. Calculations using published
data indicate that the rhizosphere resistance is of the same order of magnitude
as the root resistance when the soil moisture potential of the rhizosphere is
about -1 to -2 bars.
76:026-111
CORRELATION OF PLANT MANGANESE WITH EXTRACTABLE SOIL MANGANESE AND SOIL FACTORS,
Randall, G.W., Schlute, E.E., and Corey, R.B.
Minnesota University, Southern Experiment Station, Waseca, Minnesota.
Soil Science Society of America Journal, Vol. 40, No. 2, p 282-287, March-April
1976. 6 tab, 19 ref.
Descriptors: *Manganese, Soils, Soil properties, Soil chemical properties,
Oats, Organic matter, Greenhouses, Soil investigations, Wisconsin.
The availability of Mn on 37 low and 20 high organic matter Wisconsin soils was
determined by growing oats and ryegrass, respectively, in consecutive greenhouse
studies. The Mn uptake values were used to develop prediction equations by
means of multiple regression analysis with Mn extracted by various extracting
solutions (18 extractants for the low and 13 for the high organic matter soils)
plus various functions of soil pH and organic matter as the independent varia-
bles. On the low organic matter soils (O.M. < 6%), using only the Mn test, the
best prediction values with uptake were obtained with total Mn, and with the
0.1N H3P04 and 0.01M EDTA in IN NH40AC extractants (sq R = 57, 50 and 49%,
74
-------
respectively) . Inclusion of soil pH and organic matter with the soil test values
resulted in Mn uptake being predicted best by the 0.01M and 0.05M EDTA extract-
ants (sq R = 68% for both). The contribution of the soil test in the prediction
equation was strongest when the O.lN H3P04, 0.01M EDTA in IN NH40Ac, oTflSM EDTA
or DTPA (pH 7.3) extractants were used.
76:020-112
EXCHANGE AND HYDRATION PROPERTIES OF CU(2+) ON MIXED-ION NA(+) - CU(2+) SMECITES
McBride, M.B.
Cornell University, Department of Agronomy, Ithaca, New York.
Soil Science Society of America Journal, Vol. 40, No. 3, p 452-456, May-June
1976. 4 fig, 1 tab, 20 ref.
Descriptors: *Cation adsorption, *X-ray diffraction, Clays, Montmorillonite,
Soils, Soil investigations. Soil properties, Soil chemistry.
The exchange of Na(+)-montmorillonite with Cu(2+) was studied using X-ray
diffraction, electron spin resonance (ESR) and a specific Cu(2+) electrode in
order to investigate the hydration and exchange properties of mixed Cu(2+) -Na(+)
clay systems. With < 30% of the exchange sites occupied by Cu(2+), the clays
behave much as pure Na(+)-montmorillonite and swell freely in water. Larger
exchange levels of Cu(2+) produce more ordered interlayers at low relative humid-
ities. At high relative humidities, this ordered structure is reduced and a
solution-like environment is produced as the alumino-silicate sheets further
separate. Exchange isotherms demonstrate a large preference for Cu(2+) over
Na(+) at low Cu(2+) exchange levels, but preference for Na(+) at high Cu(2+)
levels. In contrast, Cu(2+) - Mg(2+) exchange does not show this effect,
indicating that certain exchange sites on the silicate structure preferentially
adsorb divalent cations. Thus, Cu(2+) ions are effectively removed from solution
by Na(+) - montmorillonite, but are not adsorbed in preference to other divalent
cations.
76:026-113
SOLUTION OF THE ONE-DIMENSIONAL LINEAR MOISTURE FLOW EQUATION WITH IMPLICIT
WATER EXTRACTION FUNCTIONS,
Lomen, D.O., and Warrick, A.W.
Arizona University, Department of Mathematics, Tucson, Arizona.
Soil Science Society of America Journal, Vol, 40, No. 3, p 342-344, May-June
1976. 3 fig, 2 tab, 4 ref.
Descriptors: Model studies, Soil water, Soil water movement, Soil moisture,
Irrigation, Irrigation effects.
Analytical solutions of the one-dimensional steady-state moisture flow equation
are presented for several functions modeling soil water extraction. These
functions depend directly on the matric flux potential and thus are implicit with
depth. A constant surface flux was assumed. Graphs of the matric flux potential
and cumulative uptake are given depicting the effect of model parameters and
comparing different water extraction functions. The results are useful in
obtaining a variety of water extraction distributions.
76:02G-114
WATER TRANSPORT FROM ROOTS TO SOIL,
Molz, F.J., and Peterson, C.M.
Auburn University, Department of Civil Engineering, Auburn, Alabama.
Agronomy Journal, Vol. 68, No. 6, p 901-904, November 1976. 4 fig, 20 ref.
Descriptors: Root systems, Root zone, Soil water, Soil moisture. Cotton, Soil
water movement, Mathematical models. Model studies, Hysteresis.
Numerous studies have indicated that water can flow from roots to soil (negative
direction) but little can be concluded about the magnitude of such a flow.
Therefore, experiments were performed on potted cotton plants to compare the
magnitude of water transport in the positive (soil to roots) and negative
directions. Experimental results were also compared qualitatively with the
predictions derived from mathematical models simulating root water uptake. Each
75
-------
plant was left unwatered in an environmental chamber to dry the soil from field
capacity to near the --15 bar percentage. After drying, the stem was severed
under water and the resulting water flow from roots to soil recorded by weight
changes. Results indicated that water flow in the negative direction is small
(1:36 during a 110-hour period) compared to flow in the positive direction. This
difference is thought to be due to a hysteretic, unsaturated, and possibly non-
Darcian flow phenomenon or the generation of growth-related water potentials.
Contemporary mathematical water extraction models ignore both phenomena and,
therefore, would be expected to overestimate flows in the negative direction
if "calibrated" to predict correctly flows in the positive direction.
76:02G-115
SHALLOW SUBSURFACE DRAINAGE-FIELD PERFORMANCE.
Fausey, N.R. and Brehm, R.D.
Agricultural Research Service, United States Department of Agriculture,
Department of Soil Science, North Central Region.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 1082-1084, Special Edition 1976. 3 fig, 2 tab, 8 ref.
Descriptors: *Subsurface drainage, *Drainage, Drainage practices, Drainage
effects. Soil water.
This field study shows that shallow subsurface drains (40 cm deep) remove as much
soil water as deeper drains (95 cm deep) during the growing season in the Toledo
soil. There was no structural damage to the shallow plastic draintubes from
farming operations. Thus, shallow drainage systems offer great promise as a
drainage technique for a large group of soils for which subsurface drainage is
not now recommended.
76:020-116
GRAIN SORGHUM RESPONSE TO INUNDATION AT THREE GROWTH STAGES,
Howell, T.A., Hiler, E.A., Zolezzi, 0., and Ravelo, C.
Texas A & M University, Department of Agricultural Engineering, College Station,
Texas.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 876-880, Special Edition, 1976. 4 fig, 3 tab, 14 ref.
Descriptors: *Grain sorghum, Crop response. Crop production, Drainage, Drainage
practices.
Drainage design is often limited by characterizing the crop response to specific
water inputs. This research evaluated grain sorghum response to inundation
periods of twelve days at the early vegetative, early boot, and heating growth
stages for grain sorghum. Twelve days of inundation at early vegetative growth
reduced the plant stand by 5 percent and yield by 30 percent. Inundation for
12 days at the early boot stage reduced the plant stand by 2 percent and yield
by 26 percent. Inundations after grain sorghum heading did not reduce yield.
Inundation may cause further yield reduction by physical damage to the crop such
as lodging and by increased time to maturity.
76:026-117
DIFFUSION AND MASS FLOW OF NITRATE-NITROGEN INTO CORN ROOTS GROWN UNDER FIELD
CONDITIONS,
NaNagara, T., Phillips, R.E., and Leggett, J.E.
Royal Thai Ministry of Agriculture, Department of Agronomy, Bangkok, Thailand.
Agronomy Journal, Vol. 68, No. 1, p 67-72, January-February 1976. 4 fig, 3 tab,
10 ref.
Descriptors: Nitrogen, Nitrate, Corn, Crop response, Nutrients, Fertilizers,
Fertilization, Mass flow, Model studies.
Nitrate-nitrogen, the most important source of N of non-leguminous plants, is
soluble in soil water and is transported to plant roots by both mass flow and dif-
fusion. It is, therefore, important to evaluate the relative importance of each
of these two mechanisms of transport of N03(-)N to plant roots and the environ-
76
-------
mental conditions under which each is the dominant mechanism of transport. The
elective of this paper was to present measurements of plant and soil parameters
necessary for estimating accumulation of N grown under field conditions with the
use of a theoretical model and to compare estimates of accumulation of N in the
corn plant with measured accumulation in the plant.
76:02G-118
SUBSOIL CHISELING AND SLIP PLOWING EFFECTS ON SOIL PROPERTIES AND WHEAT GROWN ON
A STRATIFIED FINE SANDY SOIL,
Kaddah, M.T.
Imperial Valley Conservation Research Center, Department of Soil Science, Brawley,
California 92227
Agronomy Journal, Vol. 68, NO. 1, p 36-39, January-February 1976. 3 fig, 2 tab,
14 ref.
Descriptors: Soil physical properties, Soil properties, Wheat, Soil investigations,
California, Crop response, Infiltration, Bulk density, Root development.
Positive crop growth response to deep tillage in sandy soils has been observed in
Imperial Valley, California. Very little information is available, however, on
the effect of different deep tillage operations and the possible causes of the
beneficial effects of deep tillage. The present field study was conducted on a
stratified fine sandy soil to evaluate the effect of subsoil chiseling and slip
plowing to a depth of 90 cm on wheat yield and soil properties. Conventional soil
disking to 20 cm depth was compared with two subsoil chiseling and two slip plow-
ing treatments. Subsoil chiseling was on 1-m centers in one and in two directions,
and slip plowing was on 2-m centers in one or two directions. The two directions
of deep tillage were at right angles to each other. Significant increases in
wheat yield resulted from deep tillage. Grain yield (metric tons/ha) were: 4.50
for disking; 5.15 for subsoil chiseling in two directions; 5.73 for slip plowing
one direction; and 6.32 for slip plowing in two directions.
76:026-119
SOIL PHYSICAL CONDITIONS AFFECTING RICE ROOT GROWTH: BULK DENSITY AND SUBMERGED
SOIL TEMPERATURE REGIME EFFECTS,
Kar, S., Varade, S.B., Subramanyam, T.K., and Ghildyal, B.P.
Indian Institute of Technology, Department of Agricultural Engineering, Kharagpur,
West Bengal, India.
Agronomy Journal, Vol. 68, No. 1, p 23-26, January-February 1976. 5 tab, 15 ref.
Descriptors: Root development, Rice, Soil physical properties, Bulk density,
Temperature, Greenhouse experiments.
Information is lacking on the performance of the rice plant due to variations in
temperature regimes in association with other soil physical properties. This in-
vestigation, carried out under controlled greenhouse conditions, evaluate the
influence of temperature and mechanical impedance of soil, as well as of their
interaction, on root and shoot growth of rice. Four submerged soil temperature
regimes thermoregulated in water baths, indicated that the maximum root and
shoot growth of rice occurred at 37 to 25 C. Irrespective of the bulk density of
soil, the total number of roots at the base and the dry weight and volume of the
rice root system significantly increased as the submerged soil temperature regime
increased from 27 to 15 C to 37 to 25 C, but decreased at 42 to 30 C.
76:02G-120
SATURATED AND UNSATURATED FLOW TO PARALLEL DRAINS,
, Department of Geological and Agricultural Engin-
Journai irSiSr^Sialnage Division, Vol. 102, No. IR2, P 221-238,
June 1976. 14 fig, 19 ref
77
-------
Descriptors: Drainage, Drainage engineering, Drainage practices, Soil water move-
ment, Soil properties, Hydraulic conductivity. Drainage effects, Drainage systems.
The purpose of this paper is to present solutions to the two-dimensional Richards
equation for open ditch drainage and to compare these solutions with conventional
more approximate methods. Specifically the objectives are to: (1) Solve the
Richards equation for drainage boundary conditions using numerical methods devel-
oped by Amerman (1); (2) compare these solutions to solutions to solutions of
the more approximate Boussinesq equation, which are normally used for drain spac-
ing predictions; and (3) determine the effect of error in the soil properties on
the solutions and to examine the relative merits of the exact and approximate
methods in view of the field variability of these properties.
76:02G-121
SOLUTIONS TO GREEN-AMPT INFILTRATION EQUATION,
Li, R., Stevens, M.A. and Simons, D.B.
Colorado State University.- Department of Civil Engineering, Fort Collins, Colorado.
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR2, p 239-248,
June 1976. 1 fig, 1 tab, 14 ref.
Descriptors: Infiltration, Soil water movement, Mathematical studies.
Two simple methods of solving the one-dimensional infiltration equations have been
developed in this study. The explicit solution is an approximation obtained by
employing a power series expansion of the logarithmic term in the infiltration
equation. The maximum error resulting from employing this simple explicit solution
is 8%. The implicit 'exact' solution is obtained by refining the explicit sol-
ution using the second-order Newton method. The maximum error resulting from
employing the implicit solution is 0.03%. These new methods have advantages over
other solutions in that they are derived from the theory of power series expan-
sion and the errors due to approximation can be evaluated theoretically. More-
over, the two methods are simple and easy to use either with a desk calculator
or in a digital computer, and they are applicable without limitation on ranges.
76:02G-122
MISCIBLE DISPLACEMENT IN SOILS,
Smajstrla, A.G., Barnes, P.L., and Reddell, D.L.
Texas A and M University, Department of Agricultural Engineering, College Station,
Texas.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 21 p, 8 fig, 1 tab, 6 equ,
8 ref.
Descriptors: Soil properties. Ions, Soil chemistry, Soil water movement.
A description of field experimental plots being used to determine soil hydrologic
properties and to monitor movement of ions in solution is presented. Steps in
the analysis of field data are also itemized, including calculation of soil hydro-
logic characteristic curves and the calibration procedures required for the instru-
mentation described.
76:02G-123
WATER AND AIR MOVEMENT IN A BOUNDED DEEP HOMOGENEOUS SOIL,
Sonu, J. and Morel-Seytoux, H.J.
Seoul National University, Department of Civil Engineering, Seoul, Korea.
Journal of Hydrology, Vol. 29, p 23-42, 1976. 14 fig, 23 ref.
Descriptors: Infiltration, Soil moisture. Soil water. Water table, Soil properties.
A methodology, based on the knowledge of the characteristic curves of the soil, is
presented to predict the infiltration rate into a soil, the evolution of the water
content in the soil and the evolution of the water table under natural hydrological
boundary conditions. Comparison with experimental results shows the method to be
accurate. In filtration rate curves are obtained for a number of situations
78
-------
involving different boundary and/or initial conditions. The results confirm the
known experimental facts and the field observations that soil-air behavior is an
important factor in infiltration phenomena.
76:020-124
CALCULATION AND PREDICTION OF THE SALT REGIME OF LOWLAND SOILS UNDER INFLUENCE
OF GROUNDWATER SALINIZATION,
Plamenac, N., Vikovik, M., and Matic, M,
'Jaroslav Cerni1 Institute for Development of Water Resources, Belgrad, Yugoslavia.
Proceedings, of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 277-289, 9 fig, 5 ref.
Descriptors: Salinity, Saline soil, Soil properties, Clays, Salt balance, Salts,
Soil water, River systems, Groundwater.
The area of lowland alluvial plain along the Danube in the zone of Belgrade is
provided with embankments controlling the river floods that results in occurrence
of secondary salinization of the soil. Owing to the construction of the 'Djerdap'
large hydroelectric power plant, the water level regime in the river is being
changed during minimum and medium discharges. This may result in aggravating the
groundwater regime and in accelerating the process of soil salinization. In order
to realize the rate of salinization in altered conditions and to estimate the
influence of various measures, calculation and prediction of the salt regime of
lowland soils has been made. The area considered is, in hydraulic view, a two-
layer porous medium with clay prevailing in the surface layer. The lower, water-
bearing layer, being hydraulically linked with the Danube, consists of sand and
gravel. For such hydrogeological conditions a methodology is elaborated for cal-
culation of the groundwater regime,' presented the basis for calculation and pre-
diction of the salt regime of lowland soils in given conditions.
76:026-125
MANAGING SALINE WATER FOR IRRIGATION,
Texas Tech University, International Center for Arid and Semi-Arid Land Studies,
Lubbock, Texas
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976. 618 p.
(see 76:05C-002)
76:02G-126
RESISTANCE TO SODA SALINIZATION OF SOME IRAQI SOILS,
Alzubaidi, A.H.
College of Agriculture, Department of Soil, Abu-Ghraib, Iraq.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 333-338. 2 tab, 10 ref.
Descriptors: Irrigation water. Soil properties, Calcium, Magnesium, Soil Chem-
istry, Saline water.
In evaluation of irrigation water containing soda, it is not sufficient to deter-
mine only the Residual Sodium Carbonate (RSC) according to Eaton. Soil resis-
tence to soda formation values (c-values) which consider the soil properties
must also be determined. Soil resistance to soda formation for thirty-eight soil
samples collected from different locations of Iraq were tested accordingly in
this work. The obtained results show that most of these samples have weak to
moderate resistance to soda formation. Soil samples with no resistance to soda
formation were not noticed. The value of soil resistance to soda formation are
determined by the amount of soluble and exchangeable calcium and magnesium in
soil samples. According to our findings irrigation water and saline water con-
taining soda could be used under Iraqi conditions for irrigation of some saline
soils and during the first stages of their reclamation. The obtained data of
this work have a considerable value in evaluation of saline water containing
soda for irrigation and reclamation purposes.
79
-------
76:02G-127
MODELS FOR PREDICTING THE IMPACT OF IRRIGATION ON SOIL SALINITY,
Bresler, E.
Agricultural Research Organization, Institute of Soils and Water, Division of Soil
Physics, Bet Dagan, Israel, and The Hebrew University of Jerusalem, Israel.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 299-315. 7 fig, 13 ref.
Descriptors: Model studies, Salinity, Salts, Irrigation, Irrigation effects,
Saline soil, Simulation analysis, Soil physical properties, Hydraulic conductivity,
Soil water. Computer programs, Optimization.
Prediction of salinization and sodication for irrigated soils is important in esta-
blishing management practice directed toward reclamation of saline soils. Models
are used which approximate the physical soil conditions by mathematical expressions
describing the simultaneous transport of water and salt. The governing non-linear
partial differential equations are supplemented by initial and boundary conditions
appropriate to soil salinization and reclamation.
76:02G-128
CONVECTIVE TRANSPORT OF SOLUTES IN AND BELOW THE ROOT ZONE.
Raats, P.A.C.
United States Salinity Laboratory, Riverside, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 290-298. 4 fig, 10 ref.
Descriptors: Return flow, Salinity, Saline water'; Irrigation, Irrigation effects,
Water quality, Dissolved solids, Root zone.
The first objective of research related to the management of saline water for irri-
gation is to find the space-time trajectories of bits of water. The second objec-
tive is to determine the change in quality of these bits of water, in particular
the changes in solute concentration due to evaporation at or near the soil surface
and selective uptake of water by plant roots. Within the root zone, the details
of the water movement and of the changes in concentration depend on the relative
magnitude of the components of the water balance, on the distribution of the water
uptake, and on the irrigation frequency. Below the1 root zone, the water table and
the drainage facility. If the drains or ditches are widely spaced relative to the
depth of the first impermeable layer, then the influence of the details of the flow
near the drains or ditches is small, and the transit times tend to be exponentially
distributed. This in turn implies some simple input/output relationships and pro-
vides a good reference for comparison of more complicated geometries and distribu-
tions of inputs and outputs.
80
-------
SECTION VIII
WATER CYCLE
LAKES (GROUP 02H)
76:02H-001
A CHLOROPHYLL A MODEL AND ITS RELATIONSHIP TO PHOSPHORUS LOADING PLOTS FOR LAKES,
Chapra, S.C. and Tarapchak, S.J.
Great Lakes Environmental Research Laboratory, National Oceanic and Atmospheric
Administration, Ann Arbor, Michigan 48104
Water Resources, Research, Vol. 12, No. 6, p 1260-1264, December 1976. 4 fig,
2 tab, 21 ref.
Descriptors: Chlorophyll, Model Studies, Phosphorus, Sedimentation, Sediments,
Eutrophication, Lake beds. Lake sediments.
A model predicting the summer concentration of chlorophyll a in a phosphorus-
limited lake is derived from simple empirical and semitheoretical relationships.
The model is rearranged and expressed as a phosphorus loading plot which agrees
closely with the predictions of Vollenweider's model. The model can be used to
gain insight into the phosphorus loading concept. The primary conclusion is that
a lake's tolerance to phosphorus loading is a function of two processes: sedimen-
tation and flushing rate. At low areal water loads, in-lake forces which remove
phosphorus to the sediments predominate. A high areal water loads, flushing of
phosphorus through the lake's outlet is the factor governing eutrophication. The
importance of the steady state assumption is also demonstrated by using data for
Lake Washington.
81
-------
SECTION IX
WATER CYCLE
WATER AND PLANTS (GROUP 021)
76:021-001
LEAD EFFECTS ON SEVERAL ENZYMES AND NITROGENOUS COMPOUNDS IN SOYBEAN LEAF,
Lee, K.C., Cunningham, B.A., Chung, K.H., Paulsen, G.M., and Liang, G.H.
Chung-Hsin University, Taiwan.
Journal of Environmental Quality, Vol. 5, No. 4, p 357-359, October-December
1976. 3 tab, 24 ref.
Descriptors: *Enzymes, *Lead, *Heavy metals. Soybeans, Ammonia, Proteins,
Calcium, Phosphorus, Leaves, Respiration.
To obtain further evidence on the nature of lead toxicity in plants, the Pb(2+)
effect of several enzyme activities and nitrogenous compounds in soybean was
investigated. Soybean seedlings were grown in culture solution treated with
lead nitrate so that final concentrations of lead Pb(2+) were 0, 20, 60, and
100 mg/liter. Soybean leaves were analyzed 10 days after lead was added to the
solution. Results showed increased respiration rate, increased activities of
acid phosphatase, peroxidase and alpha-amylase, and increases in soluble protein
and ammonia. There was no significant change in malic dehydrogenase, and total
free amino acids. A decrease was observed for glutamine synthetase activity
and nitrate. Leaf calcium and phosphorus decreased as the lead concentration
was increased in the culture solution. Increased activities of the hydrolytic
enzymes and peroxidase indicates that the lead treatment enhances senescence.
76:021-002
SIMULATION OF PLANT GROWTH BY HUMIC SUBSTANCES,
Lee, Y.S., and Bartlett, R.J.
Vermont University, Department of Plant and Soil Science, Burlington, Vermont.
Soil Science Society of America Journal, Vol. 40, No. 6, p 876-879, November-
December 1976. 1 fig, 6 tab, 15 ref.
Descriptors: Organic matter, Corn, Algae, Nutrients, Phosphorus, Iron, Growth
rates. Crop response.
Ilumic substances prepared by different techniques of extraction and from differ-
ent sources of organic materials were tested for their effects on growth of corn
seedlings and algae. Stimulating effects were confirmed with optimum concentra-
tions about 5 ppm C as Na-humate for corn and 60 ppm for algae. With corn, the
increase was 30 to 50% in nutrient solution of low organic matter soil; with
algae, about 100%. Variation of effects among humic acids derived from different
organic materials was not great. The concentrations of elements in corn seed-
lings did not show any correlation with yield or humic acid level except for P
and Fe. Phosphorus concentration was increased with increasing levels of humic
acid regardless of the yield response. Higher Fe concentration in the plant tops
and lower in roots was observed in the treatments with humic acid. The applica-
tion of humic acid to a soil low in organic matter or to nutrient solution gave
the greatest growth response, or even a slightly negative response, indicating
that the natural soil, without extraction, supplied optimim amount of humic
substances to the plants. It is suggested that a test be developed to predict
whether a given soil can furnish an optimum level of humic substances.
76:021-003
INTERACTION OF WATER POTENTIAL AND TEMPERATURE EFFECTS ON GERMINATION OF THREE
SEMI-ARID PLANT SPECIES,
Sharma, M.L.
Commonwealth Scientific and Industrial Research Organization, Division of Land
Resources Management, Wembley, Australia.
Agronomy Journal, Vol. 68, No. 2, p 390-394, March-April 1976. 2 fig, 1 tab,
16 ref.
82
-------
Descriptors: "Osmotic pressure, *Germination, Temperature, *Soil moisture,
Planting management, Semiarid climates, Environmental effects. Moisture stress
Thermal stress, *Australia, Grasses, Shrubs, Viability. '
The interactive effects of temperature with matric and osmotic potential on the
germination of Danthonia caespitosa, Atriplex nummularia and A. vesicaria are
reported. The rate and total germination of all three dryland species from
New South Wales decreased as water potential declined. Germination rates in-
creased with increasing temperature, but final germinations were greatest at
intermediate temperatures (20-25 C>. Low water potentials during optimum
temperatures produced the best germination. Osmotic and matric potential
effects were qualitatively similar, but osmotic inhibition decreased at low
temj*ratures. Both Atriplex germinated at extreme temperatures (5 and 40 C) ,
while D. Caespitosa failed to germinate. At low water potential (-15 bars) A.
nummuralia germinated from 15 to 40C and D. caespitosa at 25c, while A. vesi-
cara germinated poorly at all temperatures. A. nummularia had the greatest
resistance to environmental stress. Atriplex spp may germinate after rains
during summer as well as winter; Danthonia germination is likely only during
spring and autumn.
76:021-004
YIELD-NUTRIENT ABSORPTION RELATIONSHIPS AS AFFECTED BY ENVIRONMENTAL
GROWTH FACTORS,
Terman, G.L., Khasawneh, E.F., Allen S.E.,and Engelstad, O.P.
National Fertilizer Development Center, Muscle Shoals, Alabama.
Agronomy Journal, Vol. 68, No. 1, p 107-111, January-February, 1976.
7 fig, 17ref.
Descriptors: *Plant growth, *Nutrients, *Crop production, *Soil temperature,
*Soil environment, Nitrogen, Phosphorus, Corn(Field), Oats, Growth rates,
Root development, Soil management. Crop response. Absorption.
Temperature effects on crop yield-nutrient concentration and uptake
relationships were evaluated in three greenhouse pot experiments and as
reported in the literature on such factors. Several rates of applied nitrogen
and phosphorous were weeks at three combinations of day length and temperature;
corn grown for 4 weeks at water bath temperatures of 16 and 27C; and corn grown
for 3 and 6 weeks to compare P rates and temperatures of 16 and 21C and at
ambient temperatures (25 to 35C). Plant nutrient concentrations, especially of
P, increase with greater soil temperatures in short-duration experiments,
with little yield response to temperature. Where marked yield response occurs,
dilution of plant nutrient concentrations but higher uptakeare the dominant
trends with temperature increase up to the optimum for each crop species; the
opposite trend usually occurs at nutrient release under higher temperatures
varies with the soil fertility level and amounts of applied in uptake,
especially with nutrients having limited mobility in the soil.
76:021-005
PHOTOSYNTHATE DISTRIBUTION IN NATURAL STANDS OF SALT WATER CORDGRASS,
Hull, R.J., Sullivan, D.M., and Lytle, R.W. Jr.
Rhode Island University, Rhode Island Agricultural Experiment Station, Department
of Plant and Soil Science, Kingston, Rhode Island 02881
Agronomy Journal, Vol. 68, No. 6, p 969-972, November-December 1976. 4 tab, 14 ref.
Descriptors: Tidal marshes, Estuarine environment, Grasses, Salt marshes.
Spartina alterniflora Loisel.is a major grass species of Atlantic coast tidal
marshes which contributes heavily to the primary productivity of estaurine eco-
systems. As human activity increases in marsh areas, the capability of marsh
vegetation to withstand disturbance must be understood and constitute the basis
for formulating sound management programs. Toward this end, the seasonal distri-
bution of photoassimilated carbon was studied in S. alterniflora growing under
natural conditions. Single culms were exposed to 14C02 at various times during
the 1970 and 1971 growing seasons. Plants were harvested 1, 3, and 7 days follow-
ing exposure to 13C02 subdivided into leaves, culm, rhizomes, and roots; and
each portion assayed for 14C. Assimilate translocation reached a more or less
83
-------
stable distribution pattern within 24 hours. Throughout much of the growing sea-
son, most photosynthate was retained in leaf and culm tissue with less than 10%
translocated to roots and rhizomes. Only during early autumn was substantial
photosynthate translocated into rhizomes. This and seasonal carbohydrate levels
within perennial organs indicate that the stability of S. alterniflora stands
may be adversely affected by summer disturbance especially defoliation.
76:021-006
NITROGEN ACCUMULATION AND TRANSLOCATION IN CORN GENOTYPES FOLLOWING SILKING,
Beauchamp, E.G., Kannenberg, L.W. and Hunter, R.B.
Guelph University, Department of Soil Science, Guelph, Ontario, Canada.
Agronomy Journal, Vol. 68, No. 2, p 418-422, March-April 1976. 3 fig, 5 tab, 6 ref.
Descriptors: Nitrogen, Fertilizers, Fertilization, Nutrients, Corn, Crop response,
Crop Production.
The potential for improvement of N utilization in corn can depend on the existence
of genotypic differences. Accordingly studies were conducted to determine if N
translocation from the leaves and stalk to the ear during the period immediately
following silking depended on the genotype. In 1970, the N concentration of
individual leaf blades, stalk, and developing ears of four inbreds was determined
at the silking stage and 14 and 28 days after silking. In a similar experiment
in 1971, using bulked leaf blade samples, three of the inbreds plus their Fl hy-
brids were analyzed for N at silking and 24 days after silking. In 1970, the
apparent translocation of N from individual leaf blades differed considerably
depending on the inbred. Significant differences in N concentration in either
the stalks or developing ears occurred among genotypes in 1970 and 1971. Apprec-
iable differences were found in the apparent propensity of the inbreds to trans-
locate N to the developing ear. In 1970, apparent N translocation during the 14
to 28 day period was greater than during the first 14 days following silking.
The inbreds differed between years with respect to apparent N translocation sug-
gesting a genotype times environment interaction.
76:021-007
FIELD STUDIES OF THE CONDUCTANCE OF WHEAT LEAVES AND TRANSPIRATION,
Denmead, O.T. and Millar, B.D.
Commonwealth Scientific and Industrial Research Organization, Division of Environ-
mental Mechanics, P.O. Box 821, Canberra City, Australian Capital Territory 2601,
Australia
Agronomy Journal, Vol. 68, No. 2, p 307-311, March-April 1976. 4 fig, 9 ref.
Descriptors: Wheat, Transpiration, Stomata.
Light and water stress appear to be the main factors determining the short-term
variation of stomatal aperture in the field but their joint influences have sel-
dom been studied in the natural environment. We have examined the effects of the
irradiances and water potentials of leaves of field-grown wheat plants on their
conductances for water vapor and on canopy transpiration. Water potentials were
measured by thermocouple psychrometry or estimated from water flow rates and plant
resistances. Conductances were measured with a diffusion porometer or calculated
from meteorological measurements inside the canopy. The latter data also per-
mitted calculation of leaf irradiances and transpiration rates.
76:021-008
NITROGEN UPTAKE CHARACTERISTICS OF CORN ROOTS AT LOW N CONCENTRATION AS INFLUENCED
BY PLANT AGE,
Edwards, J.H. and Barber, S.A.
United States Department of Agriculture, Southeastern Fruit and Tree Nut Research
Station, Byron, Georgia.
Agronomy Journal, Vol. 68, No. 1, p 17-19, January-February 1976. 1 fig, 2 tab,
9 ref.
Descriptors: Nitrogen, Corn, Fertilizers, Fertilization, Roots, Soil investiga-
tions, Greenhouse experiments.
84
-------
Information is needed on the relation between concentration of N in solution, CN,
and the rate of N uptake by corn roots in order to evaluate the soil and crop
parameters affecting N fertilizer efficiency. Data on net N influx. In, vs. CN
were obtained for N levels below 150 micro M on corn plants of seven ages ranging
from 15 to 58 days (2 weeks after tasseling). it was determined by measuring
rate of N depletion from the solution in which corn plants grew Both NH+4 and
NO-3. forms of N were used. The experiments were conducted in the growth chamber
and greenhouse.
76:021-009
NITRATE-N AND TOTAL N CONCENTRATION RELATIONSHIPS IN SEVERAL PLANT SPECIES
Terman, G.L., Noggle, J.C., and Hunt, C.M. '
Tennessee Valley Authority, National Fertilizer Development Center, Soils and
Fertilizer Research Branch, Muscle Shoals, Alabama 35660
Agronomy Journal, Vol. 68, No. 4, p 556-560, July-August 1976. 5 fig, 2 tab, 9 ref.
Descriptors: Nitrate, Nitrogen, Nutrients, Greenhouse experiments. Corn, Phosphorus,
Potassium, Crop response.
Accumulation of N03-N in plants is important in regard to plant N nutritional
status, in the formation of NO2-N toxic to animals and people consuming the plants,
and as a producer of lethal gas in silos. This paper describes relationships
between N03-N and total N concentrations in plants grown in several greenhouse
pot experiments, as affected largely by response to applied N and by continuing
growth. Corn was grown in soil with 200 to 800 mg of N/pot and in nutrient solu-
tions with 2 to 16 ppm of N. Both crops were harvested at 4-day intervals.
Spinach and mustard were grown in soil with several rates of N, P, and K, and tall
fescue with 1.0 and 2.0 g of N/pot»
76:021-010
FOLIAR CONTENTS OF SODIUM AND CHLORIDE ON CITRUS ROOTSTOCKS IRRIGATION WITH SALINE
WATER.
Cerda, A., Caro, M., Fernandez, F.G., and Guillen, M.G.
Centro de Edafologia y Biologia Aplicada del Segura, Department of Fertility and
Vegetal Nutrition, Murcia, Spain.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock Texas, August 16-20, 1976, p 155-164. 1 fig, 4 tab, 20 ref.
Descriptors: Saline water, Salinity, Irrigation, Irrigation effects, ium,
Chloride.
A greenhouse experiment was conducted with six citrus seedlings used as rootstock
in containers filled with a calcareous soil, These seedlings were irrigated with
water salinized differentially with NaCl. As the experiment progressed, the
salinity levels of the water were increased except for the controls. The experi-
ment was carried out over a period of 13 months under differential irrigation
treatment. Leaf samples were collected 4 times during the experiment. Chemical
analysis of the leaf samples revealed marked differences in Na and Cl content due
to seedling variety, salinity level of irrigation water, and length of treatment
period. Leaf samples from Sour Orange seedlings contained the highest concen-
tration of Cl. Leaf samples from the Cleopatra Mandarin seedlings contained the
least amount of Cl. Leaf samples from the Kinnow seedlings contained the highest
amount of Na and those from the Sour Orange seedlings the least.
85
-------
SECTION X
WATER CYCLE
EROSION AND SEDIMENTATION (GROUP 02J)
76:02J-001
EROSION OF SELECTED HAWAII SOILS BY SIMULATED RAINFALL,
Dangler, E.W., and El-Swaify, S.A.
Hawaii University, Department of Agronomy and Soil Science, Honolulu, Hawaii.
Soil Science Society of America Journal, Vol. 40, No. 5, p 769-773, September-
October 1976. 2 fig, 6 tab, 12 ref. ARS-USDA 12-14-5001-19, 12-14-5001-40.
Descriptors: *Erosion, *Simulated rainfall, *Soil types, *Hawaii, Laboratory
tests, Soils, Soil erosion. Erosion rates, Storms, Tropical regions, Runoff,
Rainfall.
Erodibilities, or K values of the universal soil loss equation, were determined
for ten soils, representing five soil orders, on the islands of Oahu and Hawaii.
Two successive, simulated rainstorms were used, each with an approximate inten-
sity of 6.35 cm/hour and duration of 2 hours. Values obtained covered the wide
range from 0 to 0.60 metric tons/ha per metric erosion index x 0.00774 and, in
most cases, were higher for the second (wet) than for the first (dry) storm.
Erodibility values for cropped Oahu soils, belonging to four soil orders, ranged
from 0 to 0.26 for dry storms and from 0.001 to 0.41 for wet storms. Values for
volcanic ash soils on Hawaii, belonging to only two orders, had the considerably
wider range of 0.08 to 0.60 for dry storms and 0.07 to 0.51 for wet storms.
Three of these soils exhibited essentially the same credibility for dry and wet
conditions. Dry and wet values were combined to calculate a weighted mean
erodibility for each soil based on the distributions of natural rainfall through-
out the year at the test sites. The weighted erodibility of a soil at a given
location was, in general, inversely related to the amount of natural precipita-
tion at that location.
76:02J-002
EFFICIENCY OF NITROGEN, CARBON, AND PHOSPHORUS RETENTION BY SMALL AGRICULTURAL
RESERVOIRS,
Gill, A.C., McHenry.- J.R., and Ritchie, J.C.
Agricultural Research Service, United States Department of Agriculture, Sediment-
ation Laboratory, Southern Region, Department of Chemistry, Oxford, Mississippi.
Journal of Environmental Quality, Vol. 5, No. 3, p 310-315, July-September 1976
6 tab, 29 ref.
Descriptors: *Nitrogen, *Carbon, *Phosphorus, *Reservoirs, Mississippi, Nutri-
ents, Erosion, Sedimentation, Soils, Soil investigations.
Total N, total C, and readily available organic and inorganic P contents, and
particle-size distributions were determined for samples of soil and sediments
collected from three agricultural watersheds in north Mississippi. The total
quantities of N, P, C, and clay accumulated in the sediments of each reservoir
were calculated. These values were compared with those calculated from soil
losses estimated by using the Universal Soil Loss Equation. The results showed
considerable variation between the percentages of plant nutrients and of soil
particles retained in the reservoirs. These reservoirs were highly effective
in retaining eroded soil particles. However, the percentages of soil nutrients
retained in the reservoir sediments were less than the percentages of retained
soil particles.
76:02J-003
EFFECT OF PORE WATER PRESSURE ON SAND SPLASH,
Sloneker, L.L., Olson, T.C., and Moldenhauer, W.C.
United States Department of Agriculture, Agricultural Research Service, Morris,
Minnesota.
Soil Science Society of America Journal, Vol. 40, No. 6, p 948-951, November-
86
-------
December 1976. 5 fig, 3 tab, 8 ref.
Descriptors: *Pore water, Sands, Erosion, Raindrops, Rainfall.
We studied the effect of pore-water pressure and particle-size distributions on
the amount of sand splash and on the instantaneous pressure changes within a
packed sand core caused by single water drops falling on the surface. Both
splash amounts and pore-water pressure changes were affected by particle size
pore-water pressure before drop impact, and by the direction of approach to the
pore-water pressure equilibrium. Pore-water pressure increases from falling
water drops were generally greater when equilibrium pressures were approached
directly than when they were approached from minimum pressure. Sand splash was
also generally greater when equilibrium pressure was approached directly.
76:02J-004
SPLASH EROSION OF PRIMARY PARTICLES AND AGGREGATES,
Kinnell, P.I.A.
Commonwealth Scientific and Industrial Research Organization, Sediment Transport
Group, Division of Soils, P.O. Box 639, Canberra City, Australian Capital
Territory 2601, Australia.
Soil Science Society of America Journal, Vol. 40, No. 6, p 966-968, November-
December 1976. 1 fig, 1 tab, 3 ref.
Descriptors: *Eroslon, Rainfall, Soils, Soil properties, Soil investigations,
Soil tests. Precipitation.
The previously supposed similarity between primary particles and aggregates in
resisting splash erosion was shown to be partially incorrect. Mathematical
treatment of splash-cup data on which the earlier conclusion was based showed
that for surfaces containing aggregates, the quantity of material lost per unit
quantity of artificial rainfall varied with rainfall intensity; a result which
contrasts to observations for primary particles.
76:02J-005
A PORTABLE RAINFALL SIMULATOR FOR ERODIBILITY AND INFILTRATION MEASUREMENTS ON
REGGED TERRAIN,
Munn, J.R. Jr., and Huntington, G.L.
Klamath National Forest, 1215 South Main Street, Yreka, California.
Soil Science Society'of America Journal, Vol. 40, No. 4, p 622-624, July-August
1976. 1 fig, 1 tab, 17 ref.
Descriptors: *Erosion, *lnfiltration, *Rainfall simulators, Rainfall-runoff
relationships, Rainfall.
A portable rainfall simulator for field study of erosion potential and infiltra-
tion on mountainous terrain is described. Polyethylene tubes produce 3.2-mm
drops which fall 2.5m onto a 61 by 61 cm plot. The maximum rainfall intensity
is 23 cm/hour. A 16% intensity variation across the plot area was measured,
but the variation between separate simulated storms was < II for identical
intensity settings. The unit us suited to one man operation on slopes up to 60%.
76:02J-006
MINERALOGY AND RELATED PARAMETERS OF FLUVIAL SUSPENDED SEDIMENTS IN NORTHWESTERN
OHIO,
Wall, G.J., and Wilding, L.P.
Guelph University, Department of Soil Science, Agricultural Canada, Ontario,
Canada.
Journal of Environmental Quality, Vol. 5, No. 2, p 168-173, April-June 1976.
4 fig, 3 tab, 29 ref.
Descriptors: Suspended solids, Ohio, Sampling, X-ray diffraction, Mineralogy,
Calcium carbonate, Water quality. Sediments, Fluvial sediments, Soil erosion,
Erosion.
Stream water samples were collected weekly for 17 months at eight sampling sites
in the Maumee River Basin to characterize the clay mineralogy of the suspended
sediments and to determine the utility of mineralogy as a marker of the source
(rural, urban, geologic) of the sediments. X-ray diffraction analysis of the
87
-------
clay-sized sediments indicated little seasonal or downstream variability in clay
mineral composition. The quantities of mica, quartz, and vermiculite-chlorite
were 36 ± 5%, 29 ± 5%, and 20 ± 5%, respectively. The quantities of expandables,
interstratified, and kaolinite minerals were usually < 10%. The cation exchange
capacity (CEC), amorphous, fine clay, and organic matter content of the clay-
sized suspended sediments were approximately 44 meq/100 g, 4.4%, 25%, respect-
ively. Carbonate minerals were not detected in the clay-sized fraction. The
2 to 50 micro m fraction was dominated by quartz in high flow periods and second-
ary calcite in low flow periods. The stream water was calculated to be satura-
ted with calcium carbonate, thus calcite precipitation could be expected.
76:02J-007
EROSION FOR CORN TILLAGE SYSTEMS,
Siemens, J.C., and Oschwald, W.R.
Illinois University at Urbana-Champaign, Department of Agricultural Engineer-
ing, Urbana-Champaignm Illinois.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 1,
p 69-72, January-February 1976. 3 fig, 6 tab, 14 ref.
(See 76:03F-022)
76:02J-008
THE USE OF MULTIPLE REGRESSION MODELS IN PREDICTING SEDIMENT YIELD,
Weber, J.E., Gohrl, M.M., and Duckstein,L.
Arizona Univerisity, Deptarment of Management. Tucson Arizona.
Water Resources Bulletin, Vol. 12, No.l, p 1-17, February 1976. 9 fig,
4 tab, 9 ref.
Descriptors: *Sediment yield, *Regression analysis, *Model studies,
*Watershed management, *Analytical techniques, Design, Erosion, Particle size,
Soil types, Statistics.
Four commonly used models for predicting sediment yield were analyzed and comp-
ared using previously published data. Three of these models involved
logarithmic transformations. Some of the problems involved in transforming
data were discussed in the context of logarithmic transformations. The test
data pertained to 39 watersheds in 11 western states, varying in size from a
few acres to more than 50 square miles. Slope erosion is the only major
sediment source in these watersheds. Standard regressions using the four
models and test data illustrated the problems that may be caused by transfor-
mations. The standard regresssion analysis and the economic loss function for
predicting sedimetn yields. If any transformation is made to satisfy the
normality assumptions of linear regression analysis, it should be determined
from the distribution of the sample residuals.
76:02J-009
TRIPOLYPHOSPHATE AND PYROPHOSPHATE HYDROLYSIS IN SEDIMENTS,
Blanchar, R.W., and Riego, D.C.
Monsanto Philippines Incorporated, Makati, Philippines
Soil Science Society of America Journal, Vol. 40, No. 2, p 2250229,
March-April 1976. 3 fig, 2 tab, 22 ref.
Descriptors: Sediments, Sedimentation, Hydrolysis, Phosphate, Phosphorus,
Nutrients.
The rate of hydrolysis of tripolyphosphate (TPP) and pyrophosphate (PP) in
river, creek, and lake sediments was determined. Half-lives for the hydrolysis
of TPP and PP ranged from 1.6 to 2.6 and 6.7 to 27.4 days, respectively. The
influence of temperature, biological activity, and pH on the rate of TPP
and PP hydrolysis was investigated using Flat Branch Creek sediment. The rate
of TPP and PP hydrolysis increased with increasing temperature. The activation
energy was 5.415 cal/mole for TPP and 10,412 cal/mole for PP. TPP and PP hyd-
rolyzed slower in sedimetn which had been autoclaved than in non-sterlized
sediment. The half-life for TPP hydrolysis was 1.76 day at pH 5, 1.61 day at
pH 7, and 2,16 day at pH 9. The rate of PP hydrolysis was increased as pH
increased as pH increased from 5 to 7 to 9 as indicated by half-lives of 13,7,
10.0, and 7.3 days, respectively. When TPPwas added to the sediment as a Ca5-
88
-------
(P3010)2 precipitate, the rate of hydrolysis was slower than when TPP was
added as a solution.
76:02J-010
SEDIMENT YIELD-RUNOFF-DRAINAGE AREA RELATIONSHIPS IN THE UNITED STATES,
Dendy, F.E., and Bolton, G.C.
Agricultural Research Service, Sedimentation Laboratory.- Oxford, Mississippi.
Journal of Soil and Water Conservation, Vol. 31,"NO. 6, p 264-266, November-
December 1976. 5 fig, 1 tab, 11 ref.
Descriptors: *Sediment yield, *Watersheds (Basins), *Drainage area, Reservoirs,
Mathematical studies, Analytical techniques, Statistical methods, Regression
analysis, Equations, Runoff, Annual, Large watersheds. Small watersheds.
Watershed sediment yields, as determined from sediment deposits in about 800
reservoirs, were related to drainage area size and mean annual runoff. Average
sediment yields per unit of net drainage area were inversely proportional to the
0.16 power of drainage area. Average sediment yields increased sharply to about
1,860 tons per square mile of drainage area as runoff increased from^ 0 to about
2 inches, and then decreased as runoff increased from 2 to about 50 inches.
76:02J-011
USE AND MISUSE OF THE UNIVERSAL SOIL LOSS EQUATION,
Wischmeier, W.H.
Purdue University, Department of Agricultural Engineering, Lafayette, Indiana.
Journal of Soil and Water Conservation, Vol. 31, No. 1, p 5-9, January-February
1976. 2 fig, 10 ref.
Descriptors: *Soil erosion, *Equations, *Erosion control, *Farm management,
*Runoff, *Soil conservation, Sheet erosion. Sediment yield, Soil types, Rill
erosion.
The universal soil loss equation was designed to predict soil loss from sheet
and rill erosion. Variables affecting this erosion are grouped under six major
erosion factors related to erosive forces of rainfall and runoff, inherent
erodibility of a particular soil, shape and slope characteristics of the field,
farm practices, and land management. The relation of a particular factor to
soil loss is often appreciably influenced by the levels at which other factors
are present. Computed soil loss is the best available estimate rather than an
absolute value. The soil loss equation can be used to predict average annual
soil movement to guide the selection of suitable conservation practices, to
estimate the comparative utility of cropping systems, to determine optimum level
of cropping and maximum tolerable slopes, and to provide soil loss data for
erosional control needs. The researcher has to exercise judgment in selecting
pertinent factor values that will account for differences from averages and for
differences from field conditions and normal field operations.
76:02J-012
IMPROVED IMAGE-WELL TECHNIQUE FOP. AQUIFER ANALYSIS,
Chan, Y.K.
Birmingham University, Department of Civil Engineering, (England)
Journal of Hydrology, Vol. 29, No. 1/2, p 149-164, March 1976. 10 fig, 3 tab,
7 ref, 1 append.
Descriptors: *Aquifers, *Pumping, *Boundaries (Surfaces), *Drawdown,
*Methodology, Theis equation, Analytical techniques. Observation wells,
Hydraulics.
'The conventional image-well method does not yield accurate values of drawdown at
large values of elapsed time since the commencement of pumping, when the number
of images required becomes too large from the computational point of view. A
reduction in error can be achieved by selecting an alternative image pattern;
the actual form of the pattern depends on the particular boundary conditions.
This improved image-well method involves a rearrangement of the xmage pattern.
It overcomes the inherent uncertainty of the conventional method of images as
89
-------
to whether the number of images used is adequate to include a particular range of
time. The improved method was tested at length by considering particular exmaples
for nonleaky and leaky aquifers with fully-penetrating constant-discharge wells.
Recommendations were made for a more efficient method of evaluating the integral
form of the well functions.
76:02J-013
SUSPENDED SEDIMENT FILTRATION CAPACITY OF SIMULATED VEGETATION,
Tollner, E.D., Barfield, B.J., Haan, C.T., and Kao, T.Y.
Kentucky University, Department of Agricultural Engineering, Lexington, Kentucky.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 678-682, Special Edition 1976. 5 fig, 2 tab, 15 ref.
Descriptors: Sediments, Sedimentation, Vegetation, Vegetation effects. Sediment
control. Open channel flow. Open channels.
An exponential power function relating the fraction of sediment in a simulated
rigid vegetal media to pertinent physical variables was developed using linear
regression techniques and various transformations. Homogeneous' sediments and
nonsubmerging flows were studied. The mean velocity was found to be the most
influential parameter on sediment trapping followed by the flow depth, particle
fall velocity, section length, and spacing hydraulic radius. The spacing
hydraulic radius is a combination of the distance between two media elements
and depth of flow and is analogous to the hydraulic radius of an open rectangular
channel. This term was observed to be a reasonably good predictor of the length
scale in shalle flows through the experimental media. An equation similar in
form to Manning's equation utilizing the spacing hydraulic radius was observed
to be a good predictor of the mean flow velocity.
76:02J-014
PREDICTING PARTICLE-SIZE COMPOSITION OF ERODED SOIL,
Young, R.A., and Onstad, C.A.
Agricultural Research Service, United States Department of Agriculture,
Department of Agricultural Engineering, Morris, Minnesota.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 1070-1075, Special Edition 1976. 2 fig, 3 tab, 22 ref.
Descriptors: *Particle size,' Erosion, Organic matter, Pore pressure, Soils,
Soil investigations. Sediments.
A set of equations was developed for predicting particle-size distribution of
eroded soil, based on soil surface area and texture and considering organic
matter enrighment and the tendency of a soil to rill. Three parameters—
particle-size distribution of the matrix soil, organic matter, and water
content at -15 bars pore pressure gave a good estimate of the expected
particle-size distribution.
76:02J-015
CORN-SOYBEAN TILLAGE SYSTEMS: EROSION CONTROL, EFFECTS ON CROP PRODUCTION, COSTS,
Siemens, J.C. and Oschwald, W.R.
Illinois University, Department of Agricultural Engineering, Urbana, Illinois.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 30 p, 7 fig, 23 tab, 12 ref.
Descriptors: Erosion, Erosion runoff, Crop production, Corn, Soybeans, Soil
erosion, Economics.
Seven tillage systems for producing corn and soybeans were compared in terms of
erosion control, effects on crop rpoduction, and cost. Conservation tillage sys-
tems greatly reduced soil erosion. Yields were sometimes less with conservation
tillage. Total costs for the different systems were equivalent. (Skogerboe-
Colorado State)
90
-------
76:02J-016
TWO-DIMENSIONAL MODEL OF EROSION FROM A WATERSHED,
Kuh, H-c, Reddell, D.L., and Hiler, E.A.
Texas A and M University, Department of Agricultural Engineering, College Station,
Texas.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 26 p, 3 fig, 2 tab, 6 ref.
Descriptors: Model studies, Simulation analysis. Sediments, Sedimentation, Erosion,
Watersheds, Watershed management.
A two-dimensional model of erosion from a small watershed is described. The model
provides estimates of the amount of' sediment eroded from a watershed plus the
areal distribution of erosion or deposition on the watershed. Predicted values
are compared with measured data from individual storms over an 11-year period with
excellent agreement. Results are also compared with estimates of erosion made by
the original and modified versions of the Universal Soil Loss Equation.
76:02J-017
EFFECTS OF DESIGN FACTORS SEDIMENTATION BASIN PERFORMANCE,
Pennell, A.B., and Larson, C.L.
Minessota Department of Natural Resources, St. Paul, Minnesota.
Paper No 76-2020, Presented at the Annual Meeting of the American Society of Civil
Engineers, June 27-30, 1976, Lincoln, Nebraska, 6 fig, 26 ref.
Descriptors: Sedimentation, Model studies, Simulation analysis. Mathematical
studies, Sediments, Sediment control.
A mathematical model designed to evaluate sedimentation basin performance as
affected by variations in design factors produces trap efficiency curves showing
that, beyond capacity, the most significant factors are basin depth and length
of detention time. In field application, these factors take on a higher degree
of significance in the ability of the user to manipulate them as required by
site-specific conditions and trap efficiency goals. Figures 3-6 reflect the
relationship of variations in these factors in obtaining a desired output. The
results obtained are limited in that they are based on a mathematical model
developed with certain assumptions described earlier. Also, data were not avail-
able for testing the model. Accordingly, the absolute values as presented may
be somewhat in error. However, the comparative values and the relative effects
should be reliable.
91
-------
SECTION XI
WATER CYCLE
CHEMICAL PROCESSES (GROUP 02K)
76:02K-001
CALCIUM RETENTION IN RESPONSE TO PHOSPHATE SORPTION BY SOILS,
Ryden, J.C., and Syers, J.K.
Massey University, Department of Soil Science, Palmerston, North, New Zealand.
Soil Science Society of America Journal, Vol. 40, No. 6, p 845-846, November-
December 1976. 1 tab, 8 ref.
Descriptors: *Sorption, Desorption, Precipitation, Calcium, Potassium, Soil
chemistry, Soil investigations.
Retention of Ca increased in response to P sorption by soils, but was indepen-
dent of the amounts of added Ca. Rather constant values were obtained for the
molar ration of Ca/P retained (0.19 to 0.34). Retained Ca was essentially re-
covered in 1M KCl washings in contrast to the fractional recovery of sorbed P.
The retention of Ca in response to P sorption by soils is interpreted as aris-
ing from the increase in negative charge induced by P sorption.
76:02K-002
ADSORPTION OF SELENITE AND PHOSPHATE ON AN ALLOPHANE CLAY,
Raj an, S.S.S., and Watkinson, J.H.
Ruakura Agrucultural Research Center, Soil Chemistry Group, Hamilton, New
Zealand.
Soil Science Society of America Journal, Vol. 40, No. 1, p 51-54, January-
February 1976. 3 fig, 3 tab, 20 ref.
Descriptors: *Adsorption, *Clays, *Sulfate, *Phosphate, Soils, Soil investiga-
tions, Soil properties, Soil chemistry, Anions, Anion adsorption.
Selenite was adsorbed on an allophane clay from solutions of different concentra-
tions at pH 5.0, at 30C, and under a N2 atmosphere, and the amounts of sulfate,
silicate and hydroxyl ions released were measured. The results were compared
with those from a similar study with phosphate on the same clay. The results
indicate that at low concentrations both phosphate and selenite exchanged with
adsorbed sulfate, adsorbed silicate, and aquo and hydroxo groups. About three
times more phosphate than selenite was adsorbed, due mainly to phosphate dis-
placing more aquo groups and thus making the surface less positive. At high
concentrations, whereas the selenite adsorption reached a maximum, phosphate
continued to be adsorbed. The latter was due to phosphate displacing structural
silicate and probably also to disruption of hydrous oxide polymers. A two-term
Langmuir equation distinguished adsorption by surface ligand exchange exchange
from these other reactions at high concentration.
76:02K-003
CHEMICAL REDUCTION OF NITRATE BY FERROUS IRON,
Buresh, R.J., and Moraghan, J.T.
North Dakota State University, Department of Soils, Fargo, North Dakota.
Journal of Environmental Quality, Vol. 5, No. 3, p 320-325, July-September 1976
5 fig, 4 tab, 30 ref.
Descriptors: *Nitrates, *Denitrification, *Nitrogen, Chemical reaction. Chemicals.
Knowledge concerning the chemical reduction of N03(-) to gaseous products, a
process of potential practical significance as an antipollution device, is sparse.
The influence on pH on chemical reduction of N03(-)-N (approximate concentration
23 ppm) by Fe(2+) in the presence and absence of Cu(2+) was studied over a pH
range from 6 to 10. After 24-hours of controlled pH incubations under a helium
atmosphere N03(-), N20, NO, N2, and NH4(+) were determined. The initial Fe(2+)/
N03(-) mole ratio was 8. Reduction of NO3(-) was negligible in the absence of
92
-------
Cu(2+), but was pronounced above pH 7 in the presence of approximately 5 ppm
CU(o+>'. ^nation of NH4(+) increased with pH and was the dominant process at
pH 9 and 10. Nitrous oxide and N2 accumulations were greatest in the PH range
from 8 to 8.5 and negligible at pH 6 and 10. Nitrite formation was small except
at pH 9 and 10. Trace quantities of NO accumulated during incubation if the pH
was allowed to drop below 6. Levels of Cu(2+) and Fe(2+) influenced the extent
and nature of N03(-) reduction at pH 8. Maximum reduction of N03(-) (93%) and
maximum gas production (equivalent to 61% of the original N03(-) occurred when
the Fe(2+)/N03(-) mole ratio was 12 and the Cu(2+) level was approximately 10
ppm. The N20/N2 mole ratio in the evolved gases decreased as the Cu(2+) level
was increased from approximately 1 to 10 ppm and as the Fe (2+) /N03 (-) mole
ratio was increased from 8 to 12. Nitrate was relatively stable at a Cu(2+)
content of 0.1 ppm irrespective of the Fe (2+) /N03 (-) ratio.
76:02R-004
HETEROVALENT CATION EXCHANGE EQUILIBRIA IN SOILS WITH VARIABLE AND HETEROGENEOUS
CHARGE,
Munns , D . N .
California University, Department of Soil Science, Davis, California.
Soil Science Society of America Journal, Vol. 40, No. 6, p 841-845, November-
December 1976. 4 fig, 1 tab, 15 ref.
Descriptors: *Cation exchange, *Leaching, Soil properties, Soil investigations,
Calcium, Magnesium, Lime.
Divalent cations were incrementally displaced, from limed and un-limed samples
of three soils, by suspending the soils in increasing volumes of 2mM KC1. Mass
action coefficients for exchange between Ca and Mg were constant. But for the
exchange of divalent cations by K, the exchange coefficients of Kerr, Vaneslow,
Gapon, Krishnamoorthy and Overstreet, and Gaines and Thomas increased markedly
as potassium saturation or pH increased. For each cation species, separate
fractions which were relatively loosely adsorbed could be estimated by a simple
regression analysis. The loosely adsorbed Ca, which may control Ca availability
to plants, could be independently estimated by a leaching procedure. Mass action
exchange coefficients for the loosely adsorbed cations were approximately
constant under all conditions tested. The variable charge mobilized by liming
differed from the fixed charge in having a slightly higher proportion of sites
with high divalent affinity, in an Oxisol, and a much lower proportion in a
Vertisol and a Mollisol.
76:02K-005
BEHAVIOR OF CHROMIUM IN SOILS: TRIVALENT FORMS,
Bartlett, R.J., and Kimble, J.M.
Vermont University, Department of Plant and Soil Science, and Vermont Agricul-
tural Experiment Station, Burlington, Vermont.
Journal of Environmental Quality, Vol. 5, No. 4, p 379-383, October-December
1976. 2 fig, 4 tab, 9 ref.
Descriptors: *Aluminum, *Chromium, Field capacity, Soils, Soil investigations,
Adsorption, Phosphorus, Chemical reactions.
Chemical behavior of Cr(III) was studied in solutions, soil suspensions, and in
soils of contrasting characteristics incubated at field capacity moisture.
Sodium pyrophosphate, pH 4.8 NH40AC, and 0.1 M NaF appeared to extract organi-
cally bound Cr(III), whereas 1M HC1 removed inorganic Cr hydroxides and phos-
phates along with some organic Cr. Pyrophosphate and HCl extracts represented
quantities of Cr(III) removed; NH40Ac and NaF extracts appeared to characterize
small readily removed fractions, that is, intensity factors. Soil organic
complexes of Cr(III) formed at low pH and appeared to remain stable and soluble
even when soil pH's were raised to levels where the Cr would be expected to
precipitate. Adsorption and solubility behavior of Cr(III) as it varied with
pH and P treatments was similar to that of Al. Oxidation of Cr(III) to Cr(VI)
was not demonstrated at all, even under conditions of maximum aeration and high
pH.
93
-------
76:02K-006
BEHAVIOR OF CHROMIUM IN SOILS: II. HEXAVALENT FORMS,
Bartlett, R.J., and Kimble, J.M.
Vermont University, Department of Plant and Soil Science, and Vermont Agricul-
tural Experiment Station, Burlington, Vermont.
Journal of Environmental Quality, Vol. 5, No. 4, p 383-386, October-December
1976. 2 fig, 4 tab, 7 ref.
Descriptors: *Chromium, *Adsorption, Organic matter, Soils, Soil investigation,
Farm wastes. Aluminum, Phosphorus.
Adsorption and reduction of added Cr(VI) were characterized in soils with con-
trasting pH's, organic matter contents, and chemical and mineralogical proper-
ties. Presence of soil organic matter brought about spontaneous reduction of
Cr(VI) to Cr(III), even at pH's above neutrality. Reduction.did not occur in
soils very low in organic matter unless an energy source was added. Cow manure
added to practically organic-free Cecil B2 reduced Cr(VI) only after the pH had
been lowered below 3 with HC1. The solubility of Cr(VI) in the presence of
excess Al changed in a pattern remindful of orthophosphate. All of the soils,
except a pH 7.8 Cca horizon material, adsorbed Cr(VI). Presence of orthophos-
phate prevented the adsorption of Cr(VI), presumably by competition for the
adsorption sites. Consistent with this finding, KH2PO4 was found to be the
best extracting agent for Cr(VI). It was concluded that behavior of Cr(VI), if
it remains in soils, is similar to that of orthophosphate. However, unlike
phosphate, Cr(VI) is quickly reduced by soil organic matter. Thus, Cr(VI) added
to a soil will remain mobile only if its concentration exceeds both the adsorbing
and the reducing capacities of the soil.
76:02K-007
MICROBIAL INORGANIC POLYPHOSPHATES: FACTORS INFLUENCING THEIR ACCUMULATION,
Pepper, I.L., Miller, R.H., and Ghonsikar, C.P-
Ohio Agricultural Research and Development Center.
Soil Science Society of America Journal, Vol. 40, No. 6, p 872-875, November-
December 1976. 2 fig, 5 tab, 8 ref.
Descriptors: *Phosphorus, Soil chemistry, Soil properties, Soil investigations.
Infrared spectra of microbially synthesized, acid labile, inorganic P compounds
extracted from soils provided additional evidence that they are inorganic poly-
phosphates (poly P). Incubation studies with glucose amended soils demonstrated
the transient nature of naturally occurring poly P. Experiments are reported on
the conditions which optimize poly P synthesis in soil. A 2-week incubation
period (preincubation) with a source of carbon (2% glucose or 4% straw) and a
further 2-day incubation period (postincubation) after adding a source of ortho
P resulted in the maximum accumulation of poly P- The quantity of poly P also
increased with increasing rates of orthophosphate from none to 1,000 micro g
soil/g. Longer periods of postincubation reduced poly P accumulation. Poly P
synthesis was greater when relatively insoluble sources of P were added to soils
and accumulation followed the order; FePO4 . 2H20 > rock phosphate > Ca(H2P04)2 .
H20 > KH2PO4. The results suggest that poly P synthesis may accompany P solubil-
ization in soils and be an integral part of the soil P cycle.
76:02K-003
THE SLOW REACTION WHICH CONTINUES AFTER PHOSPHATE ADSORPTION: KINETICS AND
EQUILIBRIUM IN SOME TROPICAL SOILS,
Munns, D.N., and Fox, R.L.
California University, Department of Soils and Plant Nutrition, Davis, California.
Soil Science Society of America Journal, Vol. 40, No. 1, p 46-51, January-
February 1976. 7 fig, 2 tab, 18 ref.
Descriptors: *Phosphate, *Top soil. Adsorption, Soils, Soil investigations,
Kinetics, Lime, Hysteresis, Soil properties, Soil chemestry.
Dissolved phosphate was mixed with topsoil samples, and the decline in solution
phosphate concentration (P) was followed for 200-300 days by periodically
shaking and extracting subsamples with 1 or 10 mM CaC12. During the first 20-40
days, (P) declined faster in soil suspensions that were being shaken than it
94
-------
did in undisturbed soil at 0.1 bar moisture. After 40 days of reaction, shaking
time had little effect. The slow fixation had first-order kinetics with respect
to (P) . The relative rate was faster in an Andept than in three Oxisols It
was unaffected by lime, though lime increased the strength of adsorption' Equil-
ibrium was achieved at 50 days in an Andept and 100-200 days in three Oxisols
At equilibrium, the amount of adsorbed phosphate remaining labile was estimated
from values of (P), using 6-day adsorption isotherms. Labile phosphate so esti-
mated amounted to 30 to 50% of the added phosphate, implying that the residual
value of phosphate added to these soils should be substantial and permanent
except for removal by crops and erosion. Desorption isotherms diverged from
adsorption isotherms less markedly with increasing time after phosphate addition,
as if the slow reaction caused much of the apparent hysteresis.
76:02K-009
ADSORPTION OF DODECYLBENZENE SULFONATE ON NA(+)-MONTMORILLONITE: EFFECT OF SALT
IMPURITIES,
Clementz, D.M., and Robbins, J.L.
Chevron Oil Field Research Company, La Habra, California.
Soil Science Society of America Journal, Vol. 40, No. 5, p663-665, September-
October 1976. 1 fig, 12 ref.
Descriptors: Adsorption, Montmorillonite, Surfactants, Anion exchange, Clays,
Salt.
The adsorption of purified dodecylbenzene sulfonate (ABS) on Na(+)-montmorillonite
follows the Langmuir isotherm, reaching a maximum amount adsorbed which corres-
ponds to the anion exchange capacity fo the clay- When a commercial grade ABS
is used, the adsorption process is more complex and occurs in two distinct steps.
In dilute solutions, the salt impurity has a minor effect on adsorption and the
result is essentially the same as that obtained for the purified surfactant.
However, as the salt concentration is increased to a given value, enhanced
adsorption due to hemimicelle formation occurs.
76:02K-010
INFLUENCE OF IONIC STRENGTH AND INORGANIC COMPLEX FORMATION ON THE SORPTION OF
TRACE AMOUNTS OF CD BY MONTMORILLONITE,
Garcia-Miragayma, J., and Page, A.L.
California University, Department of Soil Science and Agricultural Engineering,
Riverside, California.
Soil Science Society of America Journal, Vol. 40, No. 5, p 658-663, September-
October 1976. 5 fig, 3 tab, 20 ref.
Descriptors: Cadmium, Sorption, Montmorillonite, Clays, Soils, Soil investiga-
tions, Soil chemistry. Heavy metals.
Cadmium sorption by montmorillonite from solutions in the 15 to 120 ppb range
was studied in the presence of increasing concentrations of NaC104, NaCl, and
Na2S04 solutions. The ionic strengths ranged from 0.01 to 1.00. Increasing
ionic strengths decreased the amount of Cd sorbed on the clay surfaces. The
percentage sorbed decreased from around 90% for 1=0.01 to about 50% for 1=1.00
in the C104 systems. The sorption of Cd in the chloride system was in the range
between 25 to 50% less than the C104 systems for the same ionic strength. This
was attributed to the presence of uncharged and negatively charged complexes of
Cd with Cl ligands. This fact has some implications, especially in arid zone
soils where high Cl concentrations in soil solutions are not unusual; there, Cd
will behave mainly as a neutral species (CdC12(0)) and as an anion (CaCl3(-) and
CdC14(2-)), rather than as a cation (Cd(2+)). The S04 systems showed a moderate
decrease in the amount of Cd sorbed with respect to the C104 systems for the same
salt concentrations. This observation was interpreted as due to the presence of
a fraction of Cd in solution as the CdS04(0) species.
ESTIMATING WATER SALINITY WITH GEOPHYSICAL EARTH RESISTIVITY EQUIPMENT,
Halvorson, A.D., and Reule, C.A.
Agricultural Research Service, Sidney, Montana. T=n,,a™
Soil Science Society of America Journal, Vol. 40, No. 1, p 152-153, January-
February 1976. 2 fig, 1 tab, 5 ref.
(See 76:076-003)
95
-------
76:02K-012
ATMOSPHEREIC INPUT OF SOME CATIONS AND ANIONS TO FOREST ECOSYSTEMS IN
NORTH CAROLINA AND TENNESSEE,
Swank, W.T., and Henderson,G.S.
United States Department of Agriculture, Forest Service, Coweeta Hydrologic
Laboratory, Franklin, North Carolina.
Water Resources Research, Vol.12, No. 3, p 541-546, June 1976. 3 fig, 2 tab.
23 ref.
Descriptors: Chemical properties, *Fallout, *Precipitation(Atmosphereic),
*Appalachian mountain region, *Forest watersheds, *North Carolina, "Tennessee,
*Southeast U.S., Rain, Forests, *Cations, On-site data collections, "Atmosphere,
Seasonal.
The atmospheric contributions of elements in precipitation and dry fallout to
forest ecosystems were measured at two sites in the southern Applachians.
At both sites, relative mean annual concentrations of cations in bulk precip-
itation were in the order Ca is greater than Na is greater than K is greater
than Mg. At the Coweeta Hydrologic Laboratory in North Carolina, average
annual inputs of Ca(++), Na(+),K(+), Mg(++), and NH4-N in 1970-1973 were 4,88,
3.52, 1.62, 1.01, and 0.52 kg/ha/yr, respectively. At Walker Branch,
Tennessee, the inpu-ts of these elements during the same time period were 15.73,
3.89, 2.99, 2.94, and 2.37 kg/ha/yr. The inputs of N03-J, P04-P, and C; (-) , in
1972-1973 were 2.88, 0.19, and 8.53 kg/ha/yr at Coweeta. Inputs of N03-N, and
P04-P were 4.61 and 0.55 kg/ha at Walker Branch over the same period. One
reason for differences in bulk precipitaion chemistry was greater dry fallout
for some cations at Walker Branch than at Coweeta. For both sites, dry fallout
associated concentrations of bulk precipitation except for Na( + ), which appeared
to be partly derived from marine sources. Total inputs of elements were
considered to be minimum estimates for both forest ecosystems due to sampling
and analytical methods.
76:02K-013
PHOSPHOROUS SORPTION AND DESORPTION CHARACTERISTICS OF SOIL AS AFFECTED BY ORGANIC
Singh, B.B., and Jones, J.P.
Idaho University, Department of Plant and Soil Sciences, Moscow, Idaho
Soil Science Society of Amercia Journal, Vol. 40, No, 3, p 389-394, May-June
1976. 7 fig, 1 tab, 31 ref.
Descriptors: *Phosphorous, *Sorptioh, Organic matter, Soils, Soil investigations,
Soil properties, Alfalfa, Beans, Barley, Farm Waste, Mineralization.
The influence of seven organic residues on sorption and desorption of P by a
high P-fixing soil was determined after 30, 75, and 150 days incubation.
After incubation for 30 days, all residues decreased the amount of P sorbed by
the soil, resulting in higher equilibrium solution P levels. However, after
incubating for either 75 or 150 days, the P content of the organic residues had
a marked influence on sorption of added P and desorption of sorbed P. The
critical value of P in organic residues which resulted in no tie-up of soil P
was 0.3%. Sawdust, wheat straw, and cornstalks contained < 0.3% P
decreased labile soil P and increased sorption by soil after incubating for 75
or 150 days. Alfalfa, barley, beans, and poultry manure that contained P in
excess of 0.3% decreased sorption of P, The results suggest that P fertilizer
rates estimated from sorption isotherms may need to be modified following add-
ition of organic residues.
76:02K-014
INFLUENCE OF SOIL PH ON THE AVAILABILITY OF ADDED BORON,
Peterson, L.A., and Newman, R.C.
Wisconsin University, Departments of Horticulture and of Soil Science, Madison,
Wisconsin.
Soil Science Society of America Journal, Vol. 40, No. 2, p 280-282, March-April
1976. 1 fig, 3 tab, 13 ref.
Descriptors: *Boron, Fescue, Soil properties. Greenhouses, Soil chemistry,
Soil investigations.
96
-------
A Piano silt loam with five relatively constant pH levels (47 53 58 63
7.4) was used to study the influence of soil pH on the availability'of'added B
A greenhouse study was conducted using tall fescue with five soil pH levels
and four rates of applied B essentially equivalent to 0, 5, 10, and 20 kg/ha
and five herbage harvests. Herbage yields of tall fescue were not affected by
either soil pH or B treatments: however, tissue B concentrations ranged from 8
to 739 ppm for the five harvests. Boron uptake by tall fescue was relatively
uniform for soil pH levels of 4.7, 5.3, 5.8, and 6.3 within each level of B
availability. Recovery percentages of 30 to 50% of the added B by five cuttings
of forage indicate a soil fixation of B. Highest recovery percentage was assoc-
iated with the highest rate of added B. A 2.5-fold drop in B uptake occurred
at pH 7.4 as compared with the other soil pH levels indicating substantial fix-
ation of B. Hot-water-soluble B content of the soil generally increased with
an increase in pH and with added B. The soluble B test did not predict the low
recovery of B at pH 7.4.
76:02K-015
AN EVALUATION OF JOB'S METHOD OF CONTINUOUS VARIATIONS AS APPLIED TO SOIL -
ORGANIC MATTER-METAL ION INTERACTIONS,
MacCarthy, P., and Mark, H.B. Jr.
Georgia University, Department of Chemistry, Athens, Georgia.
Soil Science Society of America Journal, Vol. 40, No. 2, p 267-276, March-April
1976. 5 fig, 31 ref.
Descriptors: Organic matter, Ions, Soil chemistry. Soil properties, Soil
investigations, Metals, Absorption.
The literature dealing with the application of Job's method of continuous
variations to the study of soil organic matter-metal ion interactions has been
reviewed, and an introduction to the fundamental chemistry necessary for an
understanding of these interactions is presented. The method of continuous
variations was applied to simple systems consisting of metal ions and mixtures
of discrete ligands. The behavior of these "model" systems was compared to
that of the more complicated soil organic matter systems. Following a consider-
ation of the fundamental principles of Job's method and of its boundary condi-
tions and limitations, it was concluded that this method is not directly appli-
cable to the study of soil organic matter-metal ion interactions. This conclu-
sion was substantiated by experiments carried out on the simple "model" systems
as well as those on fulvic acid itself. Explanations are proposed to account
for the deceptive results which were obtained when this method was erroneously
applied by other workers to the investigation of soil organic matter-metal ion
interactions in the past. Possible interferences, due to scattering of light,
during the study of soil organic matter-metal ion reactions by UV-visible
absorption spectroscopy are considered.
76:02K-016
THE RELEASE OF NITROGEN FROM SULFUR-COATED UREA AS AFFECTED BY SOIL MOISTURE,
COATING WEIGHT, AND METHOD OF PLACEMENT,
Prasad, M.
M.J. Woods and Associates, 13 Kilbarrack Grove, Dublin 5, Ireland.
Soil Science Society of America Journal, Vol. 40, No. 1, p 134-136, January-
February 1976. 5 tab, 13 ref.
Descriptors: *Nitrogen, *Urea, *Soil moisture, Calcareous soil, Soil investi-
gations, Nitrification, Nitrite, Volatility-
Information on the release of N from sulfur-coated urea (SCU) as affected by
soil moisture in the aerated range is lacking. Laboratory incubation experi-
ments were therefore conducted on two soil to study the release of N from SCU
as affected by soil moisture in the aerated range, coating weight (SCU-28 and
SCU-9), and method of placement (on one soil only). In the calcareous Princes
Town soil the release of N from SCU increased with increasing moisture through-
out the 9 weeks of study- In acid Talparo soil similar trends were present up
to 3 weeks, but at 6 and 9 weeks maximum release of N occurred at medium
soisture (soil moisture at pF 2.4) and minimum release at low moisture (soil
moisture at pF 3.5).
97
-------
76:02K-017
THEORETICAL CONSIDERATION ON NITRITE SELF-DECOMPOSITION REACTIONS IN SOILS,
Van Cleemput, 0., and Baert, L.
Ghent University, Laboratory of Physical and Radiobiological Chemistry, Belgium.
Soil Science Society of America Journal, Vol. 40, No. 1, p 322-324, March-April
1976. 3 fig, 10 ref.
Descriptors: Soils, Soil investigations, Soil properties, Nitrite.
The spontaniety of different nitrous acid self-decomposition reactions was
calculated for different sets of activities of the participating components at
pH 4, 7, and 9. These calculations showed that nitrous acid preferentially
decomposes spontaneously to NO and N03(-) instead of self-decomposition to NO
and M02 or N204. The higher the pH the larger the region of nitrous acid
stability. Theoretical evidence for the reaction of nitrous and nitric acid
with formation of N02 was obtained.
76:02K-018
INFLUENCE OF SALT AND ALKALI ON IONIC EQUILIBRIA IN SUBMERGED SOILS,
Pasricha, N.S., and Ponnamperuma, F.N.
International Rice Research Institute, Los Banos, Laguna, Philippines.
Soil Science Society of America Journal, Vol. 40, No. 3, p 374-376, May-June
1976. 4 tab, 15 ref.
Descriptors: Salt, Salinity, Alkali, Clays, Sodium, Sampling, Ions, Iron,
Manganese, Soils, Soil investigations, Soil properties.
To clarify the effects of salt and alkali on Fe(2+) and Mn(2+) equilibria in
submerged soils, Maahas clay (a. Haplustalf) was amended with NaCl and NaHC03
to give initial electrical conductivities of 5, 10, 20, and 25 mmhos/cm at 25C
and exchangeable Na percentages of 5, 10, 15, 20, and 25, respectively. The
amended soils and an untreated control were kept submerged in 16-liter pots in
a greenhouse at 25-30C. The soil solutions, drawn anoxically by gravity, were
analyzed fortnightly for Eh, pH, C02, and the major ions. As the salt level
increased, the concentrations of all cations except K(+) and Na(+) decreased.
In spite of wide variations in pH, Eh, ionic strength, and the concentrations
of Fe(2+) and Mn(2+) in the soil solutions, the values of the expressions,
pE - pFe(2+) +3pH, pE - 1.5 pFe(2+) + 4 pH, pE + pH, and pH - 0.5 pMn(2+) -
0.5 pC02 were nearly equal to 17.9, 23.3, 7.3, and 4.1, respectively, indica-
ting that even in the salt and alkali treated soils, the Fe(OH)3 - Fe(2+) and
Fe3(OH)8 - Fe(2+) systems controlled the solubility of Fe(2+) while the MnC03 -
H2) - C02 system regulated the solubility of Mn(2+).
76:02K-019
ZINC ADSORPTION ISOTHERMS FOR SOIL CLAYS WITH AND WITHOUT IRON OXIDES REMOVED,
Shuman, L.M.
Georgia University, Department of Agronomy, Georgia Experiment Station, Athens,
Georgia.
Soil Science Society of America Journal, Vol. 40, No. 3, p 349-352, May-June
1976. 2 fig, 3 tab, 16 ref.
Descriptors: *Zinc, *Adsorption, Georgia, Clays, Soils, Soil properties,
Iron oxides, Soil investigations.
The clay fraction from four predominant Georgia Soils sampled at two depths
was separated and the iron oxides removed from a portion of each clay sample.
These clays were equilibrated with five Zn solutions to measure Zn adsorption.
The data conformed to the Langmuir adsorption isotherm. Langmuir coefficients
were used to evaluate the Zn adsorptive capacities of the clays and bonding
energies for Zn. Adsorptive capacities and CEC values for the clays from
Decatur cl and Leefield Is soils were higher than those for clays from the
Cecil si and Norfolk Is soils. Differences in adsorptive capacities were not
consistent between depths nor between samples with or without Fe oxides.
However, removal of the Fe oxides increased the capacity to adsorb Zn in more
instances than it decreased this capacity. Zinc adsorptive capacities were
directly related to the CEC values for the clays. When comparing those samples
with and without J'e oxides removed, bonding energies .were inversely related to
adsorptive capacities.
98
-------
76:02K-020
WASTEWATERS IN THE VADOSE ZONE OF ARID REGIONS: HYDROLOGIC INTERACTIONS
Ma,nn r J • F • r Jr. '
Ground Water, Vol. 14, No. 6, p 367-373, November-December 1976. 6 fig, 12 ref.
Descriptors: *Waste storage, *Waste water disposal, *Arid lands, *Vadose water
*Nevada, Groundwater recharge, Evapotranspiration, Soil water, Water table
Moisture content, Field capacity, Pollutants, Soil water movement. Infiltration
Leachate, Nuclear meters, Clays, Storage, Monitoring.
In truly arid regions there is essentially no direct penetration of rainfall
Such water is quickly dissipated by capillarity-assisted evaporation or through
rapid evapotranspiration by. short-lived annuals. Where perennial xerophytes cover
the ground surface, the extensive shallow root systems quickly utilize all of the
rainfall stored in the soil. Beneath the soil zone is the lower part of the
vadose zone, extending to water tables at depths of tens to hundreds of feet.
Almost always these vadose zones have moisture contents well below field capacity.
Regardless of the cause, these dry vadose zones are capable of holding additional
water, at least up to field capacity. And no water-carried pollutants can reach
the water table from the ground surface until a pre-wetted path has been formed
for the entire vertical distance. A practical use of this water-holding capacity
can be made in the design of wastewater tailings ponds, with predictable safety
and with great economic benefit. However, only in predictable geologic condi-
tions, and in limited amounts can the use of this water-holding capacity be
recommended. On the other hand, to make no use whatsoever of these great natural
dry sponges would be an economic waste.
76:02K-021
DENITRIFICATION MEASURED DIRECTLY FROM NITROGEN AND NITROUS OXIDE GAS FLUXES,
Rolston, D.E., Fried, M. , and Goldhamer, D.A.
California University, Department of Land, Air, and Water Resources, Davis,
California 95616
Soil Science Society of America Journal, Vol. 40, No. 2, p 259-266, March-April
1976. 8 fig, 2 tab, 17 ref.
Descriptors: Denitrification, Nitrogen, Fertilization, Soils, Soil water, Lysim-
eters, Diffusion, Leaching.
The amount of denitrification is generally the unknown in attempts to evaluate
the fate of N fertilizers applied to soils. Substantial error can result when
denitrification is determined from the difference between measurements of plant
uptake, residual soil N, leaching, and the amount of N applied. An ir^pnendent,
direct measure of denitrification potentially has merit by containing the
error from direct measurement and not a cumulative error from several arements.
Nitrate at a rate of 300 kg of N/ha and enriched with 20 and 10 atom percent
excess N-15 was applied to laboratory columns and a field plot, respectively.
The columns were maintained at soil-water pressure heads of -22 and -70 cm. The
field plot was maintained at a soil-water pressure head of approximately -10 cm
in the upper 10 cm of soil. , The field plot was cropped with perennial ryegrass.
The columns and field plot were instrumented with tensiometers, soil solution
samplers, and gas samplers. The concentration and isotopic ratio of N03, N2, and
N20 were measured as a function of soil depth and time. The gaseous concentra-
tion gradients and measured apparent diffusion coefficients were used to calculate
the fluxes of (N-15) 2 and /N-15) 20 gas from the soil. Residual soil N, plant
uptake, and leaching were measured in order to calculate denitrification by dif-
ference. For the laboratory columns, the amount of denitrification determined
directly compared favorably with that determined by difference.
99
-------
SECTION xn
WATER CYCLE
ESTUARIES (GROUP 02L)
76:02L-001
PARTIAL DEPLETION OF SALINE GROUNDWATER BY SEEPAGE,
Van Dam, J.C.
Technische Hogeschool, Department of Civil Engineering, Delft, (Netherlands).
Journal of Hydrology, Vol. 29, No. 3/4, p 315-33S, April 1976. 14 fig, 3 tab,
4 ref.
Descriptors: *Saline water intrusion, *Encroachment, *Saline water systems,
*Hydrogeology, *Seepage, *Model studies, Land reclamation, Water table, Pumping,
Freshwater, Recharge, Saline water, Groundwater.
The geohydrologic conditions prevailing in the western part of the Netherlands,
particularly the numerous so-called polders, were analyzed with respect to
seepage of saline water. The polders are reclaimed lakes or parts thereof and
have a land elevation of up to several meters below mean sea level. The ground-
water levels in the polders are artificially controlled at depths of about 0.3 to
2 meters below land surface by means of embankments, sluices, and pumping
stations. A highly schematized, one-dimensional model was developed to
investigate the effects of reclamation of the deep polders. Seepage of saline
water induced by reclamation of these polders was found to be of temporary
nature. This temporary seepage comes from diminution of the volume of saline
water present in the aquifer. The permanent seepage of saline water, currently
recharged by sea water, increases with lower polder levels. The results of this
model study indicated interesting tendencies, but more complicated models and
study of transient effects are needed to interpret the actual field conditions.
100
-------
SECTION XIII
WATER SUPPLY AUGMENTATION AND CONSERVATION
SALINE WATER CONVERSION (GROUP 03A)
76:03A-001
THE INTEGRATION OF DESALINATION PLANT WITH EXISTING AUSTRALIAN WATER RESOURCES,
Kemeny, L.G.
New South Wales University, School of Nuclear Engineering, Kensington
(Australia).
Journal of Hydrology (Amsterdam), Vol. 28, No. 2/4, p 429-448, 1976. 8 fig,
4 tab, 14 ref, 2 append.
Descriptors: *Desalination plants, *Water resources, *Australia, *Water supply,
Water utilization, Arid lands, Coasts, Economics, Hydrologic aspects, Salinity,
Freshwater, Water storage, Water distribution (Applied), Costs, Size sites,
Energy.
Two-thirds of Australian land is arid; even the well-watered coastal areas are
prone to prolonged droughts. Thus, the capital investment in water supply
storage and distribution facilities is very high. These economic and ecological
conditions demand alternative sources of fresh water supplementation, probably
desalination. A summary of Australian water resources is given, including
geographical distribution of surface discharge and runoff, typical salinities of
underground waters, and permissible limits of salinity. Considered next are the
patterns of fresh water usage and the related costing practice; these are
subdivided into domestic, industrial and agricultural supplies. A description of
an existing desalination plant on the Western Australian Coast is given. Finally
general factors influencing the integration of desalination plant with existing
water resources in Australia are summarized; discussed are water storage and
distribution; plant size, siting and energy source; and integration and costing
studies.
76:03A-002
MANAGING SALINE WATER FOR IRRIGATION.
Texas-Tech University, International Center for Arid and Semi-Arid Land Studies,
Lubfaock, Texas.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976. 618 p.
(see 76:05C-002)
101
-------
SECTION XIV
WATER SUPPLY AUGMENTATION AND CONSERVATION
WATER YIELD IMPROVEMENT (GROUP 03B)
76:03B-001
PLASTIC-REINFORCED ASPHALT SEEPAGE BARRIER,
Frobel, R.K., and Cluff, C.B.
Arizona Water Resources Research Center, Tucson, Arizona.
Paper Reprint, Journal of the Irrigation and Drainage Division, ASCE, Vol. 102,
No. IR3, Proceedings Paper 12430, p 369-380, September 1976. 8 fig, 1 tab, 8
ref. OWRT A-059-ARIZ(3). 14-31-0001-5003.
Descriptors: Adhesion, *Asphalts, Linings, Membranes, *Plastics, *Reinforce-
ment, *Seepage, Water resources, *Barriers, Equipment, Testing.
This leport is concerned with laboratory equipment development, laboratory
testing, and field investigations of a water seepage barrier consisting of
plastic-reinforced asphalt. Three testing methods were utilized and evaluated
in the asphalt-plastic-asphalt-chip-coated (APAC) membrane investigation. The
first test method evaluated the hydrostatic puncture resistance of an asphalt-
polyethylene combination. This test confirmed the hypothesis that the asphalt
effectively increases the puncture resistance of the APAC membrane over that of
plain polyethylene. The second test investigated the slope stability of a pro-
tective APAC chip seal. It was found that a typical 3/8-in.(9.5mm) cover
aggregate remained stable on constructed slopes of 3:1 and 4:1 and also remained
stable on a 2:1 slope up to a surface temperature of 122F(50C). The third test
method evaluated adhesive materials and determined the best suited adhesive for
sealing polyethylene overlaps. Subsequent field investigations resulted in
equipment development that increased construction efficiency in the installation
of the APAC membrane.
76:03B-002
EVALUATION OF A MONTHLY WATER YIELD MODEL,
Haan, C.T.
Kentucky University, Department of Agricultural Engineering, Lexington, Kentucky.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 1,
p 55-60, January-February 1976. 6 fig, 3 tab, 11 ref.
(See 76:02A-003)
76:03B-003
AERIAL SPRAYING OF PHREATOPHYTES WITH ANTITRANSPIRANT,
Davenport, D.C., Martin, P.E., and Hagan, R.M.
California University, Water Science and Engineering Section, Davis,
California.
Water Resources Research, Vol. 12, No. 5, p 991-996, October 1976. 6 fig,
6 tab, 7 ref.
Descriptors: *Antitranspirants, *Spraying, *Phreatophytes, *Application
methods, Consumptive use, Streamflow, Groundwater, Groundwater basins, Water
conservation. Water yield improvement, Transpiration, Transpiration control,
Chem-control, Cottonwoods, Canopy, Foliar, Foliar application.
The use of antitranspirants for water conservation by reducing phreatophyte
transpiration is discussed. Experiments were conducted to determine whether
aerial spraying of a wax-based antitranspirant emulsion would provide adequate
spray coverage and reduce transpiration. Multiple passes were made with (1) a
fixed wing plane on salt cedar, cottonwood, and willow and (2) a helicopter on
salt cedar. Spray coverage was also conducted on the ground. Scanning elec-
tron microscope photomicrographs showed considerable antitranspirant on foliage
in the upper canopy and lesser amounts in the lower: the film was detected
even 24 days after spraying. Aerially applied antitranspirant increased resis-
tance to leaf water vapor diffusion by 150 percent during the first few days
and by 80 percent thereafter. Results then show that (1) good coverage can be
102
-------
achieved by multiple passes of the aircraft and deep antitranspirant spray
penetration into dense canopies is not as important as coverage of the outer
foliage and (2) transpiration rates can be retarded without foliar damage.
However, full assessment of the antitranspirant spraying must await more exten-
sive..field trials.
76:036-004
CONSERVING WATER BY ANTITRANSPIRANT TREATMENT OP PHREATOPHYTES,
Davenport, D.C., Martin, P.E., Roberts, E.B., and Hagan, R.M.
California University, Water Science and Engineering Section, Davis, California.
Water Resources Research, Vol. 12, No. 5, p 985-990, October 1976. 6 fiq
9 tab, 32 ref.
Descriptors: *Antitranspirants, *Phreatophytes, *Application methods, *Water
conservation, Transpiration control, Transpiration, Water yield improvement,
Foliar, Foliar application. Canopy, Cottonwoods, Spraying, Hydrology, Watersheds
(Basins), Stomata.
The use of antitranspirants in hydrology seeks to curtail transpiration from
forested watersheds and riparian vegetation, such as salt cedar, without
removing the vegetation or damaging the' ecological balance. There are two main
groups of antitranspirants: (1) stomatal inhibitors, which prevent the stomatal
pore from opening fully, and (2) film-forming materials, which externally cover
or plug stomatal pores. Basic information is provided on foliar coverage of
three phreatophytes (salt cedar, willow, and cottonwood) by a wax-based film-
forming antitranspirant and the effects of this coverage on transpiration,
diffusive resistance, and water potential. Antitranspirants were applied by
hand sprayer or backpack mist blower. Transpiration was measured by periodic
weighing of potted plants and by gas hygrometer. Resistance to water vapor
diffusion from the foliage was measured by a porometer and plant water potential
by a pressure chamber. The results are presented. Foliar application by hand
sprayer or backpack mist blower of a wax-based antitranspirant increased
resistence to water vapor diffusion from phreatophyte foliage and decreased
transpiration, indicating the potential of this non-destructive approach to
water conservation.
103
-------
SECTION XV
WATER SUPPLY AUGMENTATION AND CONSERVATION
USE OF WATER OF IMPAIRED QUALITY (GROUP 03C)
76:03C-001
SALT AND WATER BALANCE IN IMPERIAL VALLEY, CALIFORNIA,
Kaddah, M.T. and Rhodes, J.D.
Imperial Valley Conservation Research Center, Brawley, California 92227
Soil Science Society of America Journal, Vol. 40, No. 1, p 93-100, January-
February 1976. 4 fig, 2 tab, 13 ref.
Descriptors: *Salinity.- *Salts, Soil salinity, Water salinity, Root zone, Ground
water, Surface runoff, Effluents, Water quality, California
(see 76:05B-016)
76-.03C-002
SALINITY MANAGEMENT WITH DRIP IRRIGATION,
Hoffman, G.J.
United States Department of Agriculture, United States Salinity Laboratory,
Riverside, California.
Drip/Trickle Irrigation, Vol. 1, No. 2, p 14-22, August 1976. 9 fig, 1 tab.
Descriptors: Salinity, Saline soil, Saline water, Irrigation, Irrigation practices,
Irrigation systems.
The minimum leaching fraction for producing maximum crop yield with high-frequency
irrigation is being established. Based on 2.5 years of data, the minimum leaching
requirement under high-frequency irrigation is about 5% for wheat and grain sorghum,
and between 10 and 15% for lettuce with 2.2-mmho/cm irrigation water. In citrus,
after 2 years under drip irrigation, there were no yield or fruit quality differ-
ence between 5 and 20% leaching with 1.2-mmho/cm irrigation water, although there
are significant differences in the distribution and concentration on soil salinity-
Adequate irrigation management in salt-affected soils requires knowledge of and
control over the soil matric potential and soil salinity. Soil matric potential
can be measured with tensiometers or other soil matric potential sensors, and
soil salinity can be detected with salinity sensors or the four-electrode conduc-
tivity probe. In salt-affected soils, knowledge of soil salinity in the root zone
is required as feedback information to control irrigation from measures of soil
matric potential. This knowledge will allow drip/trickle users to optimize the
use of their systems for quality and productivity.
76:03C-003
PROCEEDINGS OF THE CONFERENCE ON SALT AND SALINITY MANAGEMENT,
California University, Davis, California 95616
Proceedings of the Conference held at Santa Barbara, California, September 23-24,
1976, Report #38, December 1976. 166 p.
Descriptors: *Salts, *Salinity, *Water management, *Water quality control,
legislation, *Political aspects, *Institutions, Irrigation, Waste water disposal,
California, Operations, Technology, Soil tolerance. Water utilization.
(see 76:05G-020)
76:03C-004
USE OF HIGHLY-SALINE WATER IN CITRUS IRRIGATION,
Goell, A., E-Rais, M., and El-Wahidi, A.
Agricultural Research Orginization, The Volcani Center, Division of Citriculture,
Bet Dagan, Israel
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 236-245. 2 fig, 3 tab, 7 ref.
104
-------
Descriptors: Saline, water, Salinity, Orchards, Irrigation, Irrigation effects,
Chlorine, Crop response, Oranges, Soil moisture, Nutrients.
High Cl salinities in the water used to irrigate Citrus orchards in the Gaza Region
on the southern coastal plain of Israel have caused yields to peak earlier, and to
decline more rapidly than in orchards of the same age irrigated with water contain-
ing minimal amounts of Cl. Vegetative growth on such trees becomes less vigorous
leaves develop chlorosis, age quickly and drop earlier. Overall yields are lower
and long-term profitability of the orchard is further reduced by the high incidence
of 'creased1 fruit. Various cultural treatments have been tried in an irrigation-
frequency experiment in a Valencia orange orchard with the aim of stimulating new
and more vigorous growth in the trees. A treatment combining a period of moisture
stress in early summer (stoppage of irrigation) and the supply of a highly-avail-
able nitrogenous fertilizer when irrigation was resumed in mid-summer proved effec-
tive in stimulating much vigorous late summer vegetative growth. The effects of
this treatment and its long-term effects on growth and cropping are discussed.
76:03C-005
SALT TOLERANCE OP BEANS UNDER A SAND MULCH CULTURE,
Parra, M.A., and Romero, G.C.
Catedra de Edafologia, Escuela Tecnica Luperior de Ingenieros Agronomos, Cordoba
and Valencia, Spain.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 220-235. 5 fig, 6 tab, 20 ref.
Descriptors: Salt tolerance, Crop production, Beans, Saline soil, Salinity, Crop
response.
Salt tolerance of two cultivars of beans grown for green consumption under a sand
mulch culture has been studied. The influence of the growing season and the time
of soil salinization on salt tolerance as well as the tolerance during germination
have also been investigated. Under early salinization regimes and high evapotran-
spiration demands, yields were reduced by 50% of the maximum at ECse of 6 mmhos/cm.
This latter figure means an almost twofold higher salt tolerance was increased by
almost 100% when the crop was grown under low evapotranspiration demands (fall
culture). An additional 30% salt tolerance increase was observed when soil salin-
ization was delayed twenty days. Increasing yields of first picking and dry pod
matter observed with increasing soil salinity suggest that soil salinity acceler-
ates fruit ripening.
76:03C-006
PROBLEMS OF MANAGING GEOTHERMAL WATERS FOR IRRIGATION,
Peterson, H.B. and Shupe, J.L.
Utah State University, Department of Agricultural and Irrigation Engineering,
Logan, Utah.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 211-219. 5 fig, 2 tab, 8 ref.
Descriptors: Irrigation, Irrigation water, Geothermal studies, Groundwater.
With the development of geothermal water as a source of energy, there will be con-
siderable 'spent water' available for other purposes. In the United States most
of the known geothermal basins are in the Western States where water is scarce
and the need and temptation to use spent geothermal water for irrigation is great.
This will also likely be true in other parts of the world. In this discussion
we are concerned with minimizing or avoiding adverse effects caused by chemical
constituents and not the possible benefits or damage to crops from the heat in
the water
76:03C-007
SOIL SALINITY AND PLANT NUTRITIONAL STATUS,
Finck A
Institut'f. Pflanzenemahrung u. Bodenkunde, Neue Universitat, Kiel, West Germany.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 199-210. 9 fig, 1 tab, 19 ref.
Descriptors: Saline soils, Crop production, Nutrients, Nitrogen, Calcium, Fertil-
ization, Salinity.
105
-------
Plants on saline soils not only suffer from water deficiency, but also from nutri-
tional disturbances. Especially at low and medium degrees of salinity the surplus
of some elements (nonnutrients or nutrients) or the real or induced deficiency of
nutrients creates a nutritional stress that is often responsible for yield depres-
sions. The extreme nutrient situation can partly be corrected by fertilization
improving the ratio between necessary and unwanted ions in the plants as well as
by improvement of other minimum factors such as trace element supply. The base
of fertilization, however, should be reliable plant diagnosis considering that
the usual limiting values for optimum supply or tolerance will have to be partly
modified under saline conditions.
76:03C-008
CROP SALT TOLERANCE: EVALUATION OF EXISTING DATA,
Maas, E.V., and Hoffman, G.J.
United States Salinity Laboratory, Riverside, California
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 187-198. 8 fig, 1 tab, 23 ref.
Descriptors: Crop production, Salinity, Salts, Salt tolerance.
An extensive review and evaluation of the past 30 years' literature on crop salt
tolerance was undertaken to assess the relative tolerance of as many agricultural
crops as possible. Most crop yields decrease linearly as salt concentrations are
increased above a tolerance thershold. Our best estimates of the threshold salin-
ity and the yield decrease as a function of salinity are presented graphically
for over 60 agricultural crops. The criteria required to express salt tolerance,
and the factors that influence and limit the applicability of these data are dis-
cussed.
76:03C-009
PREDICTED AND ACTUAL YIELD DECLINE FROM FIFTY PERCENT INCREASE IN SALINITY OF THE
COLORADO RIVER,
Robinson, F.E.
California University, Division of Agricultural Sciences, Davis, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 170-174. 1 tab, 1 ref.
Descriptors: Crop production, Sprinkler irrigation, Irrigation, Soil moisture.
Salinity, Saline water, Carrots, Onions, Beans.
Six crops were grown in a sprinkler irrigated field with water applications based
upon 10 cm available moisture and an application to pan evaporation ratio of 0.90.
Utilizing data from the California Committee of Consultants, increase in water
salinity from ECw=1.35 mmho/cm to 2 mmho/cm predicted yield decreases of greater
than 10% for carrot, onions, and beans. These three crops exhibited significant
field yield reductions of the same order of magnitude as that predicted. In the
wheat, cabbage, and alfalfa yield predictions, the declination was less than 10%
and the field yield reductions were not significant. Normal field trial yield
variation tends to obscure the first 10% yield reduction due to salinity.
76:03C-010
TRANSPLANTATION OF JUNCUS SSP. ON SALINE SOILS IN EGYPT,
Zahran, M.A., El-Bagoury, I.H., Abdel Wahid, A.A., and El-Demerdasy, M.A.
Mansoura University, Department of Botony, Mansoura, Egypt.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 142-154. 2 fig, 3 tab, 11 ref.
Descriptors: Salinity, Saline soil, Crop production. Phosphorous, Nitrogen,
Fertilization.
The saline lands of Egypt occupy vast areas along the Mediterranean Sea and the
Red Sea coasts and in the inland deserts. Cultivation of these areas with hylo-
phytic plants that proved to be of economic importance inav extend the cultivable
lands of Egypt and supply the country with raw materials for iiu^-rial purposes.
106
-------
Juncus rigidus and J. acutus are salt tolerant and fiber plants. Their culms can
be used as raw material in paper industry and their seeds may be used as a source
of drugs and oils. Transplantation experiments in saline soil associated with
Manzalla Lake of Egypt were carried out. The results were encouraging Both
species succeeded to grow but the vegetative yield of Juncus rigidus was, relative-
ly, higher than that of J. acutus. Nitrogen-phosphorous fertilization treatments
showed marked effect on the vegetative yields. The fresh and dry weights as well
as the lengths, of the culms increased progressively with the increased amount of
nitrogen in soil but phosphorous fertilizer showed reverse effect. Excess phos-
phorous in soil hinder the uptake of nitrogen by Juncus plants.
76:030011
COMPOSITION OF SALINE DRAINAGE WATER IN IRAQ AND ITS USE,
Hanna, A.B.
State Organization of Soils and Land Reclamation, Baghdad, Iraq
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 590-597, 4 tab, 4 ref.
Descriptors: Drainage, Drainage water, Salinity, Salts, Dissolved solids, Calcium,
Magnesium, Saline water, Water quality, Leaching.
Three years of study of the composition of drainage water indicated that the sea-
sonal fluctuation of total salt concentration is more pronounced than the kind
of salts, depending on agricultural activities and the status of water regime of
the rivers. Total soluble salts in the drainage water varies from 7-32 mmhos/cm
while the SAR ratio is about 5 in low saline samples and approaches 30 in other
high saline water. An example is given, here, to make use of some of these saline
waters in the first stages of leaching a highly saline alkali soil. This study
indicated that about 20% of good quality water required for leaching was saved by
using a 10 mmhos/cm drainage water having an SAR ratio of about 10 to an adjacent
soil having in the top layer a conductivity of 124 mmhos/cm and an SAR of 20.
76:03C-012
SYSTEM FOR MANAGING SALINE AND RUN-OFF WATER FOR FRUIT AND CROP PRODUCTION IN
ARID REGIONS OF MEXICO,
Gavande, S.A., Cluff, C.B., and Nahlawi, N.
Food and Agriculture Organization/United Nations Development Program Project,
Universidad, Autonoma Agraria 'Antonio Narro', Saltillo, Coahuila, Mexico.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 575-589. 6 fig, 3 tab, 3 ref.
Descriptors: Mexico, Saline soils, Return flow, Runoff, Tailwater, Irrigation
water, Saline water, Orchards, Economics, Crop production, Water quality.
Nearly 30% of the total area in Northern Mexico is extremely arid and presents
some saline and alkali problems. Irrigation water from wells when available is
often saline. A feasibility study by FAO for orchard development in this area
showed that by using runoff water from compacted inter-row area and storing and
recirculating this water, economic returns would be satisfactory. Total system
of working model consisted of low cost water harvesting subsystem, simple water
harvesting agri-subsystem and efficient compartmented tank system. A 20 hectare
system consisting of 10 hectares of fruit and 10 hectares of dry farming were
found to give internal return of 25% and benefit cost ratio of 3:1.
YIELDS AND ACREAGE AS VARIABLES IN PLANNING THE USE OF SALINE IRRIGATION WATER:
A CASE STUDY FROM IRAN,
Diestel, H., and Treitz, W.
Technical University Braunschweig, Leichtweiss Institute for Water Research,
Braunschweig, West Germany. , „ . .. ,
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 480-493. 3 tab, 26 ref.
107
-------
Descriptors: Salinity, Irrigation water, Water quality, Saline water, Salts, River
systems, Economics, Crop production, Leaching.
Economic aspects of the salinity of irrigation water are discussed. A case of
preliminary economic planning with irrigation water quality is described. Tribu-
taries of the Hableh Rud River contributed about 4% to the water discharge, but
about 50% to the salt discharge of the river. Two schemes to divert tributary
flow are evaluated from the economical (national) and financial (private) points
of view. Two alternatives of use would exist with the improved river water; to
apply it to the area which is irrigated without project implementation, which,
in the long run, would result in yield increases, or to make use of the reduction
in leaching requirement by increasing the irrigated area. It is shown that the
latter alternative can be expected to be more profitable. Values are given in
Rials per unit of salinity of river water which the farmers of Garmsar and the
national economy could pay per year for water improvement. It is estimated that,
in this case, it would be only 25% more expensive to gain land by salinity reduc-
tion than by additional supply of equal quality irrigation water.
76:030-014
CHEMICAL RECLAMATION OF SOLONETZ-SOLOCHAKS IN THE ARARAT PLAIN AND THE POSSIBILITY
OF UTILIZING SALINE WATERS FOR LEACHING AND IRRIGATION,
Petrosian, G.P.
Research Institute of Soil Science and Agrochemistry, Ministry of Agriculture of
the Armenian SSR, USSR.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 466-479. 7 fig, 2 tab.
Descriptors: Sodium, Saline soils, Salinity, Sulphuric acids, Crop production,
Leaching, Irrigation, Irrigation water, Irrigation practices.
Waste sulphuric acid and iron vitriol are the most efficient amendments for improv-
ing soda saline soils. Their ameliorative influence may be revealed in a very
short time. Applying sulphuric acid and iron vitriol causes neutralization of
alkaline reaction and desalinization of the soil, sharply increasing infiltration
rate and permeability in it. On the reclamated soils high-yielding annual and
perennial crops are cultivated, securing very quick returns of capital investments.
76:03C-015
POTENTIAL FOR SALINE WATER IRRIGATION OF TROPICAL SOILS,
El-Swaify, S.A., Sinanuwong, S., Daud, A.R., and Tengah, A.
Hawaii University, College of Tropical Agriculture, Department of Agronomy and
Soil Science, Honolulu, Hawaii.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 358-375. 4 fig, 4 tab, 16 ref.
Descriptors: Saline water, Salts, Soil chemical properties, Soil physical proper-
ties, Irrigation, Irrigation practices. Hydraulic conductivity.
The effects of waters with defined salt concentration and ionic composition on
the chemical and physical properties of irrigable tropical soils belonging to
four Orders were investigated. Studies of cation exchange equilibria indicated
that soil affinities for sodium ion adsorption were generally in the order of
Oxisols less than Aridosols less than Mollisols less than Vertisols. As a group,
however, these soils exhibited less tendency to accumulate detrimental sodium ions
on the exchange complex than is known for temperate arid region soils. Evaluation
of soil physical responses to changes in water quality by direct stability and
hydraulic conductivity methods showed that soil susceptibilities to structural
breakdown depended on the presence or absence of swelling minerals. Both were in
the order of Aridisols less than or equal to Oxisols less than Mollisols less
than Vertisols. It was, concluded that a promising potential exists for using
saline waters for irrigation of certain soils in the tropics when use of such
waters is necessary for expanding available water resources.
108
-------
76:030-016
IRRIGATION WITH SALINE WATER IN SOUTH TEXAS,
Hipp, B.W.
Texas Agricultural Experiment Station, Weslaco, Texas.
Proceedings of the International Salinity Conference,"Texas Tech University
Lubbock, Texas, August 16-20, 1976, p 345-349. 4 fig, 6 ref.
Descriptors: Texas, Irrigation water. Saline water, Water quality, Salts Leach-
ing, Cotton, Saline soil.
South Texas and northeastern Mexico is highly dependent upon irrigation water with
an EC that ranges from 1 to 4.4 mmhos/cm. Studies were conducted on sandy loam
soil to determine the influence of irrigation water quality on salt distribution
in the soil profile and to determine the importance of summer and fall rains in
leaching salts from irrigated land. Cotton was irrigated with water with EC values
of 1.2, 2.6, and 4.2 mmhos/cm. Soil salinity was monitored with salinity sensors
after 0, 20.3, and 30.5 cm of irrigation water was applied and after 32.7 cm of
rainfall. Before irrigation, EC of the 15 to 120 cm soil profile was 2.5 mmhos/cm
but two irrigations (10 cm each) increased soil salinity in the 15-60 cm profile
to about 2.3 and 4.5 mmhos/cm for the 1.2, 2.6, and 4.2 mmhos/cm irrigation water,
respectively. Three irrigations with 4.2 mmhos/cm water resulted in soil EC of
7.2, 6 and 5 mmhos/cm at 15, 30, and 60 cm depths, respectively. Soil salinity
in the root zone was decreased after 32.7 cm of rainfall in July and August. This
salt application and subsequent leaching pattern is typical of the irrigated area
of the South Texas and northeastern Mexico and it allows growers to use relatively
saline water for irrigation.
76:030-017
IRRIGATION WITH SALINE WATER IN THE PECOS VALLEY OF WEST TEXAS,
Moore, J., and Hefner, J.J.
Texas Agricultural Experiment Station, Pecos, Texas.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 339-344. 1 tab, 7 ref.
Descriptors: Texas, Saline water, Irrigation water, Dissolved solids, Crop pro-
duction, Drainage, Irrigation effects. Irrigation efficiency. Saline soil. Salinity.
The Pecos Valley of West Texas has been under cultivation for 30 years with pump
irrigated saline water averaging 2500 ppm total salts. This quantity of salts
has restricted selection of crops to more salt tolerant plant species and required
excessive water for leaching. Primary problems are associated with establishment
of crops. Once beyond the seedling stage, growth and yield have generally been
acceptable. Internal drainage remained good and severe salt buildup has not occur-
red because of favorable types of clay minerals and ionic composition of irrigation
waters. The major problem facing the area is high production cost, especially
that of pumping irrigation water. Expiration of a long term natural gas contract
in 1975 led to a 500 percent increase in 1976. This has curtailed farming oper-
ations and has placed added emphasis on more efficient use of water. New concepts
and modifications of present irrigation management systems are being introduced.
The saline nature of the water and soils require that any changes in the overall
management systems be carefully investigated to assess its future consequences on
agriculture in the area.
76:03C-018
SALINITY EFFECTS ON CORN YIELD, EVAPOTRANSPIRATION, LEACHING FRACTION, AND IRRI-
GATION EFFICIENCY,
Stewart, J.I., Hagan, R.M., and Pruitt, W.O.
California University, Department of Land, Air and Water Resources, Water Science
and Engineering Section, Davis, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 316-332. 3 fig, 4 tab, 10 ref.
Descriptors: Salinity, Crop production, Evapotranspiration, Leaching, Irrigation
efficiency, Irrigation water, Saline water. Salt balance, Corn.
In each individual cropping situation there exists a 'limiting salt concentration'
(LSC) at which irrigation water can no longer be absorbed by roots of plants and
109
-------
transpired. The LSC in any particular farm field and season depends on crop type,
soil texture, and salinity of the upper profile soil solution in which germination
and early root activity takes place. Irrigation water can only be concentrated
to the LSC which is determined by the early conditioning of the crop, and which
in future may be estimated by a preplant measurement of the upper soil salinity.
Thus, a 'refusal fraction* (RF) also exists which is dependent on the LSC, and
on the salinity of the irrigation water supply. The RF is the portion of applied
water which remains in the soil and which contains the concentrated salts at the
LSC level, when transpiration has effectively ceased. The RF pertains whether
water supply is adequate for the crop or is limited, and whether or not leaching
occurs. If these is leaching during the growing season in question, the RF con-
stitutes the minimum leaching fraction which will maintain the salt balance of
the root zone.
76:03C-019
IRRIGATION WITH SALINE WATER UNDER DESERT CONDITIONS,
Hardan, A.
Higher Agricultural Council, Baghdad, Iraq
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20,' 1976, p 165-169. 2 tab, 6 ref.
Descriptors: Crop production, Groundwater, Rainfall, Salinity, Saline water.
Orchards, Crop response, Salts.
A Desert Development Program was designed and initiated to determine the potential-
ity of agricultural production under desert conditions through the development of
available groundwater and harvested rainfall. The suitability of different manage-
ment practices of water, soil, and crops are under study in several stations in
the Western Desert of Iraq. The central station is located about 60 km west of
the town of Haditha at an elevation of 320 m above sea level. The average rain-
fall of this station is 11 cm. Irrigation waters of about 500, 2000, and 4000 ppm
soluble salt concentration were used to irrigate pear trees, wheat, and potatoes.
Data on soil salinity, tree growth, and yield of wheat and potatoes were collected
and analyzed. The results show no significant difference in the growth of pear
trees or in wheat production at all levels of water salinity- However, the pro-
duction of potatoes decreased significantly at the 4000 ppm level of soluble salt
concentration.
110
-------
SECTION XVI
WATER SUPPLY AUGMENTATION AND CONSERVATION
CONSERVATION IN DOMESTIC AND MUNICIPAL USE (GROUP 03D)
76:030-001
LONG-TERM EVALUATION OF SLOW-RELEASE NITROGEN SOURCES ON TURPGRASS,
Waddington, D.V., Moberg, E.L., Duich, J.M, and Watschke, T.L.
Community College of the Finger Lakes, Canandaigua, New York.
Soil Science Society of America Journal, Vol. 40, No. 4, p 593-597, July-August
1976. 5 fig, 2 tab, 3 ref.
Descriptors: *Turf grasses, *Kentucky bluegrass, *Ureas, *Nitrogen, Nutrients,
Fertilization, Crop response.
Short-term studies with slow-release nitrogen sources have not provided infor-
mation on the changes in response that may occur with continued use of a given
material. In this study eight nitrogen sources were used to fertilize "Merion"
Kentucky bluegrass for 7 consecutive years to obtain long-term results. Fertili-
zers used were urea, Uramite, IBDU (isobotylidene diurea), Urex(urea-paraffin
matrix), ADM (plastic coated urea), Milorganite (activated sewage sludge), and
two complete (NPK) fertilizers, with two-thirds of the nitrogen from ureaform
or IBDU and the remainder soluble. Urea was applied every other week and the
other fertilizers were applied one, two or three times per season to obtain
total N of 1.46, or 2.44 kg/100 sq m. Weekly clipping yields and color ratings
were used to evaluate turfgrass response to the fertilizer treatments. Milor-
ganite, uramite, and IBDU produced more uniform growth than Urex, ADM, and the
complete fertilizers. Response to Urex, ADM, and the complete fertilizer with
IBDU was similar, and was often characterized by excessive growth after applica-
tion. The greatest increase in response with continued use occurred with Uramite,
which was the least efficient fertilizer in the first two years. At the end of
the 7-year period, determinations of yield, color, and total soil N indicated
that Uramite had the greatest residual effect.
Ill
-------
SECTION XVII
WATER SUPPLY AUGMENTATION AND CONSERVATION
CONSERVATION IN INDUSTRIAL USE (GROUP 03E)
76:03E-001
WATER AVAILABLE FOR ENERGY—UPPER COLORADO RIVER BASIN,
Hansen, D.C.
Utah State Engineer's Office, Salt Lake City, Utah.
Journal of the Water Resources Planning and Management Division, Vol. 102, No.
WR2, Proceedings of the American Society of Civil Engineers, p 341-348, November
1976. 1 tab, 5 ref.
Descriptors: *Colorado River, *Water resources, *Water rights, *Energy, Water
supply.
The Upper Colorado River Basin has abundant deposits of fossil fuels and miner-
als, and numerous projects are in progress, planned or projected, to extract
those resources. The first question that needs to be answered to make it pos-
sible for these projects to become reality is the-availability of water. The
Upper Colorado River Basin states are presently depleting 60% of the water
apportioned to them under the Colorado River Compact of 1922. Of the 40% remain-
ing it is difficult to specify the exact amount of water available for future
development because of the uncertainty of the amount of water needed to satisfy
the Indian water rights and the amount of water that has been committed to
various projects by the Upper Colorado River Basin states. A joint effort
between Federal, state, and Indian leaders is needed to make water available
for energy development and to insure that all Indian water rights are satisfied.
112
-------
SECTION XVIII
WATER SUPPLY AUGMENTATION AND CONSERVATION
CONSERVATION IN AGRICULTURE (GROUP 03F)
76:03F-001
DISTRIBUTION OF WATER AND IONS IN SOILS IRRIGATED AND FERTILIZED FROM A TRICKLE
SOURCE,
Bar-Yoseph, B., and Sheikholslami, M.R.
Agricultural Research Organization, Division of Soil Chemistry and Plant Nutri-
tion, Bet Dagan, Israel.
Soil Science Society of America Journal, Vol. 40, No. 4, p 575-582, July-August
1976. 4 fig, 12 tab, 11 ref.
Descriptors: *Irrigation practices, Irrigation efficiency, Irrigation systems,
*Subsurface irrigation, *Application methods, Irrigation, Water distribution
(Applied), Infiltration, Ion transport. Mathematical models, Moisture content,
Soil types, Discharge (Water), Clays, Denitrification, Sands, Phosphates,
Nitrates, Hydraulic conductivity.
Trickle irrigation is becoming increasingly important in modern agriculture,
but the simultaneous distribution of water and nutrients emerging from a trickle
source has been insufficiently studied. This paper reports a laboratory study
of simultaneous distributions of water, N03-N and Pin clay and sandy soils irri-
gated daily from a trickle source. Hydraulic conductivity data, water retention
curves and absorption isotherms to the soils were determined to enable verifi-
cation of mathematical models against the experimental results obtained under
various conditions. Adding identical amounts of water but increasing the trickle
discharge rate in the sandy soil irom 250 to 2,500 mililiters per hour increased
the vertical movement of the wetting front and decreased horizontal movement.
In a sequence of three cycles of irrigation with a nutrient solution, losses of
nitrate were observed in the clay soil, probably due to denitrification pro-
cesses. The restricted mobility of the phosphate ions, even in the sandy soil,
implies that a preirrigation mixing of P in the soil, supplemented by its addi-
tion to the irrigation solution, is necessary to obtain a uniform P concentra,-
tion in the soil volume.
76:03F-002
COMPARISON OF IRRIGATION SCHEDULES BASED ON PAN EVAPORATION AND GROWTH STAGES
IN WINTER WHEAT,
Prihar, S.S., Khera, K.L., Sandhu, K.S., and Sandhu, B.S.
Punjab Agricultural University, Ludhiana, India.
Agronomy Journal, Vol. 68, No. 4, p 650-653, July-August 1976. 2 fig, 3 tab,
11 ref.
Descriptors: *Irrigation efficiency, Irrigation effects, *Wheat, *Evapora-
tion pans, *Growth stages, Crop response, Water conservation, Irrigation
practices. Water management (Applied), Crop production, Irrigation water.
Water use efficiency improved by irrigation of winter wheat (Triticum aestivum)
using a ratio of some fixed amount of irrigation water (IW) to pan evaporation.
PAN-E, (cumulative evaporation from U.S. Weather Bureau class A pan less rain
since previous irrigation) and scheduling according to growth stages. In a
2-year field study, IW/PAN-E ratios of Q.75 and 0.9 for scheduling irrigation
to winter wheat irrespective of growth stage were compared with a combination
of IW/PAN-E with growth stages and the conventional technique of irrigating at
five growth stages. The 0.75 ratio irrespective of growth stage produced as
large a grain yield as irrigation at five growth stages while using an average
of 12 cm less irrigation. Combining IW/PAN-E with growth stages did not improve
the yield. The major advantage of this approach is that the farmer need not
change the amount of water from one application to the next. With rain, the
interval for the next irrigation would increase.
113
-------
76:03F-003
AN EXPERIMENTAL BURIED MULTISET IRRIGATION SYSTEM,
Worstell, R.V.
Agricultural Research Service, Snake River Conservation Research Center,
Kimberly, Idaho.
Presented at the 1975 Winter Meeting of the American Society of Agricultural
Engineers, December 15-18, 1975, Chicago, Illinois, 15 p, 8 fig, 2 tab, 7 ref.
Descriptors: *lrrigation, *Irrigation systems. Irrigation design, Irrigation
effects, Irrigation efficiency. Irrigation practices. Water conservation, Soil
moisture, Soil moisture movement. Design criteria, Construction, Operations.
Criteria for the design, construction, and operation of an experimental buried
lateral, gravity multiset irrigation system are presented. The system has a
potential water application efficiency of 80% with very little runoff or erosion
without automatic controls. With automatic controls and with water available on
demand, light, frequent irrigations can be applied with efficiencies of 90 to
95%. The energy required to operate the system is minimal and labor require-
ments involve only periodic inspection and maintenance services. Cost and bene-
fit estimates indicate that this.system may be economically feasible, practical,
and attractive at a time of rising energy costs and labor shortages.
76:03F-004
EVAPORATION REDUCTION FROM SOIL WITH WHEAT, SORGHUM, AND COTTON RESIDUES,
Unger, P.W., and Parker, J.J.
United States Department of Agriculture', Southwestern Great Plains Research
Center, Bushland, Texas.
Soil Science Society of America Journal, Vol. 40, No. 6, p 938-942, November-
December 1976. 5 fig, 2 tab, 20 ref.
Descriptors: *Wheat, *Grain sorghum, *Cotton, Evaporation, Soils, Soil proper-
ties, Soil water. Water conservation, Mulching.
Wheat, grain sorghum, and cotton are major irrigated crops on the Southern
Great Plains. While irrigated wheat residue mulches increase soil water storage
and decrease evaporation, very limited data are available regarding the effect-
iveness of grain sorghum and cotton (stalk) residues for this purpose. There-
fore, this study was conducted to compare the effectiveness of wheat, grain
sorghum, and cotton residues for decreasing evaporation under three potential
evaporation conditions and to determine which residue characteristics are most
effective for decreasing evaporation. The laboratory tests were conducted on
Pullman clay loam soil columns at potential evaporation rates of 0.66, 0.92, and
1.29 cm/day. Besides a bare soil (check) treatment, residue treatments were 4,
8, 16, and 32 metric tons/ha for sorghum and cotton, and 8 metric tons/ha of
wheat residue. Multiple regression analyses indicated that residue thickness
most strongly affected cumulative evaporation and evaporation rates at selected
days of the study. Other independent variables considered were potential
evaporation, relative humidity, and residue specific gravity, application rate,
and surface coverage.
76:03F-005
PHOSPHORUS FERTILIZATION WITH DRIP IRRIGATION,
Rauschkolb, R.S., Rolston, D.E., Miller, R.J., Carlton, A.B., and Burau, R.G.
California University, Department of Land, Air, and Water Resources, Davis,
California.
Soil Science Society of America Journal, Vol. 40, No. 1, p 68-72, January-
February 1976. 3 fig, 3 tab, 10 ref.
Descriptors: *Phosphorus, *Nutrients, *Fertilization, *Fertilizers, Irrigation,
Irrigation system, Irrigation effects, Irrigation operation and maintenance.
Application of plant nutrients with drip irrigation systems in desirable for
labor and energy savings and flexibility in timing nutrient applications.
Evaluations of P movement in the soil and uptake by tomatoes were made when
orthophosphate and glycerophosphate were applied through a drip irrigation
system and in camparison with 26 kg of P/ha banded below the seed at planting.
114
-------
A significantly higher P content was measured in seedling leaves when 26 ka of
P/ha was applied by drip irrigation than when the same rate was banded No
differences in P content of whole tops of seedlings were measured at equal rates
of inorganic or organic P applied through the drip system. There was a signifi-
cant linear response of P uptake to P rate. With drip irrigation, orthophos-
phate moved a much greater distance into the soil than had been previously
observed for comparable application rates per hectare. Glycerophosphate moved
5 to 10 cm farther through the soil at application rates of 6.5 and 13 kg of
P/ha than did orthophosphate.
76:03F-006
AMMONIA VOLATILIZATION AND NITROGEN UTILIZATION FROM SULFUR-COATED UREAS AND
CONVENTIONAL NITROGEN FERTILIZERS,
Matocha, J.E.
Texas A and M University Agricultural Research Extension Center, Corpus Christi,
Texas.
Soil Science Society of America Journal, Vol. 40, No. 4, p 597-601, July-Auqust
1976. 2 fig, 2 tab, 17 ref.
Descriptors: *Ammonia, *Nitrogen, *Ureas, Nutrients, Fertilization, Calcareous
soils, Acidic soils, Cation exchange, Corn, Lime.
Ammonia volatilization was measured on acid and calcareous soils receiving sul-
fur-coated ureas (SCU) and highly soluble N fertilizers. Surface and mixed
applications of SCU-30 (30% dissolution rate), SCU-20 (20% dissolution rate),
uncoated (NH2)2CO, NH4N03, and (NH4)2S04 were made with and without lime to a
fallowed acid fine sand . Without lime, top dressed NH4N03, SCU-20, SCU-30, and
(NH4)2SO4 lost < 1% while (NH2)2CO lost 18.5% of added N in 14 days. Topdress-
ing lime with N caused more NH3 loss from (NH4)2S04 than from (NH2J2CO during
the initial 48 hours. However, accumulative loss for 14 days were 51.5, 22.5,
9.0, and 1.7% from (NH2)2CO, (NH4)2S04, SCU-30 and SCU-20, respectively. Incor-
porating the lime with the soil prior to N addition reduced NH3 loss > 50% as
compared to surface application, but mixing N with the limed acid soil did not
reduce NH3-N losses. Mixing SCU with the soil appeared to increase release rate
of N over topdressing, but this effect was not detected in plant response.
Nitrogen uptake by corn on the acid soil substantiated some of the conclusions
regarding measured NH3-N losses. Ammonia losses from N mixed with the finer
textured calcareous clay loam were generally insignificant. Surface applied
(NH2)2CO and (NH4)2S04 lost'significant amounts of NH3-N while losses from SCU
and NH4NO3 were negligible.
76:03F-007
INFLUENCE OF LONG TERM TILLAGE, CROP ROTATION, AND SOIL TYPE COMBINATIONS ON
CORN YIELD,
Van Doren, D.M. Jr., Triplett, G.B. Jr, and Henry, J.E.
Ohio Agricultural Research and Development Center, Department of Agronomy and
Agricultural Engineering, Wooster, Ohio.
Soil Science Society of America Journal, Vol. 40, No. 1, p 100-105, January-
February 1976. 5 tab, 12 ref.
Descriptors: *Till, Crop production. Crop response, Corn, Crops, Soybeans,
Ohio, Soils.
Studies to compare the relative ability of a wide range of tillage and crop
rotation combinations (3 multiplied by 3 factorial) to sustain corn production
on several soils typical of Ohio were initiated in 1962. Soils were a well-
drained Wooster silt loam, an imperfectly drained Crosby silt loam, a very
poorly drained Hoytvllle silty clay loam, and a very poorly drained Toledo clay.
Tillage treatments were no-tillage; plow and then plant; and plow, disk, and
plant. Rotations were continuous corn, corn-soybeans, and corn-oats with each
crop appearing each year in each rotation. Results are reported only for plots
having equal plant density within a site-year combination, and adequate weed
control. Corn yie'lds were remarkably insensitive to tillage. The two plowed
treatments had equal yield for virtually all years at each site within the same
rotation.
115
-------
76.-03F-008
SULFUR-COATED FERTILIZERS FOR SUGARCANE: I. PLANT RESPONSE TO SULFUR-COATED
UREAS,
Gascho, G.J., and Snyder, G.H.
Florida University, Department of Plant Nutrition, Belle Glade, Florida.
Soil Science Society of America Journal, Vol. 40, No. 1, p 119-122, January-
February 1976. 1 fig, 2 tab, 14 ref.
Descriptors: *Fertilizer, *Fertilization, *Sugarcane, Urea, Nutrients, Crop
response. Crop production, Nitrogen, Soils.
Crop growth and yield on sand soils is often limited by low N availability due
to leaching losses from the soil. This study was initiated to determine if
sulfur-coated urea (SCU) could supply adequate N nutrition and eliminate the
need for repeated N applications for sugarcane grown on previously uncropped
Immokalee fine sand in southern Florida. Single applications of two SCU's were
compared with split applications of (NH4)2S04(AS), each at three N rates, 56,
112, and 168 kg/ha. Application of SCU at planting in November resulted in
excellent growth and high leaf N concentrations in the spring but did not provide
optimum N throughout the growing season. Leaf N concentrations in late summer
and tonnages of sugarcane and sugar for SCU plots approached, but did not equal,
those attained with four applications of AS. Higher tonnages were recorded for
the slower releasing SCU than for the faster releasing source but both SCU
sources released large amounts of N before the warm summer months when N is
required in the highest quantities. The data indicate that SCU's which release
N more slowly and/or later application date should provide better N nutrition
and eliminate the need for several split applications of soluble sources.
76:03F-009
SULFUR-COATED FERTILIZERS FOR SUGARCANE: II. RELEASE CHARACTERISTICS OF SULFUR-
COATED UREA AND KC1,
Snyder, G.H., and Gascho, G.J.
Florida University, Department of Soil Chemistry, Belle Glade, Florida.
Soil Science Society of America Journal, Vol. 40, No. 1, p 122-126, January-
February 1976. 4 fig, 2 tab, 11 ref.
Descriptors: *Nitrogen, *Potassium, *Fertilizers, *Fertilization, Leaching,
Nutrients, Soils, Crop production, Florida.
Nitrogen release from sulfur-coated urea and K release from S-coated KC1 were
examined by several techniques under field conditions in three south Florida
sand soils in order to assist in the interpretation of plant response data and
to provide insight into the use of three slow-release fertilizer materials.
Decreased thickness of S coating, higher temperatures and higher moisture gener-
ally favored nutrient release. However, considering the range of field conditions
involved in the studies, variations in N and K release were comparatively small.
Release was rapid during the first 6 months, averaging 70-80% of that applied,
but was much slower thereafter.
76:03F-010
TIME-DEPENDENT LINEARIZED INFILTRATION: III. STRIP AND DISC SOURCES,
Warrick, A.W., and Lomen, D.O.
Arizona University, Department of Soils, Water, and Engineering, Tucson, Arizona.
Soil Science Society of America Journal, Vol. 40, No. 5, p 639-643, September-
October 1976. 3 fig, 12 ref.
Descriptors: Soil water, Soil water movement, Irrigation, Irrigation effects,
Irrigation practices. Irrigation systems.
Water flow from strip and disc surface sources is analyzed using an approach sim-
ilar to previous investigations with line and point sources. A line of closely
spaced trickle irrigation emitters often wets a surface strip of finite width;
similarly, for a single emitter the surface wetted pattern is a disc. Lines of
equal matric flux potential are wider and more shallow for these sources than
wetting patterns for the line and point. The moisture regime is independent of
the source shape and depends only on the total flow rate for regions beyond
approximately two times the strip width or disc radius.
116
-------
76:03F-011
WATER USE AND PRODUCTIVITY OF WHEAT UNDER FIVE IRRIGATION TREATMENTS
Ehlig, C.F., and LeMert, R.D.
Agricultural Research Service-United States Department of Agriculture, Western
Region, Brawley, California.
Soil Science Society of America Journal, Vol. 40, No. 5, p 750-755
October 1976. 6 fig, 1 tab, 11 ref. P '
Descriptors: Irrigation Irrigation effects, Irrigation practices, Wheat, Crop
production. Consumptive use, Soil moisture, Evapotranspiration, Lysimeters.
Water use and yield of wheat compared under five irrigation treatments using
wheat planted in a silty clay loam soil in December and harvested in May Water
was applied at five rates from 11% more to 23% less than evapotranspiration (ET)
from a weighing lysimeter planted to the same crop. Equal quantities of water
per irrigation were applied at 76 mm in the pre-emergence and the first post-
emergence irrigations and 102 mm in later irrigations. For a 102-mm application,
an irrigation was scheduled whenever cumulative ET from the lysimeter reached
91, 102, 112, 122, and 132 mm of water, since the last scheduled irrigation for
the treatments. Total amounts of 485 to 688 mm of water were applied in five to
seven irrigations. Soil water content to 1.5 m decreased progressively with
water applications below ET. The soil water content was determined gravimetri-
cally before each irrigation and water use determined from differences in soil
water content between irrigations plus the amount of applied water. Seasonal
water use decreased progressively from 677 to 540 mm as irrigation frequency
decreased, although water use in all treatments was similar for the first 120
days. Yields decreased as water applications decreased, except between the
treatments equal to ET and at 10% below ET. At the three driest treatments
yield decreased proportionately with water use, indicating that water use effic-
iency was not increased by restricting water use below ET from adequately
watered wheat.
76:03F-012
NITROGEN, PHOSPHORUS, AND POTASSIUM UTILIZATION IN THE PLANT-SOIL SYSTEM: AN
ANALYTICAL MODEL,
Smith, O.L.
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Soil Science Society of America Journal, Vol. 40, No. 5, p 704-714, September-
October 1976. 11 fig, 2 tab, 61 ref.
Descriptors: Nitrogen, Phosphorus, Potassium, Model studies, Crop production,
Crop response. Absorption, Nutrients, Simulation analysis.
An intermediate-resolution analytical model of nitrogen, phosphorus, and potas-
sium utilization in the plant-soil system was developed and tested. Starting
from specified natural or artificial sources in the soil, element transport to
root absorption surfaces was modeled in terms of diffusion, mass flow, and soil
buffering mechanisms. Element uptake was described by carrier theory formalism,
and assimilation was based on four premises about the roles of N, P, K, and
photosynthate in cell chemistry- There were three main objectives of the model.
The first was to predict the first-order interactive growth response of particu-
lar plant species to any combination of these macronutrients supplied in the
soil medium. Species parameters required by the model include root absorption
rate and certain cell chemistry reaction rates. The second objective was to
make the model sufficiently general to describe a broad range of species. It
was built upon common denominator principles of physiology condensed from avail-
able experimental data on corn, bean, pine, etc. In this generic sense it is a
measure of what plants have in common. The third objective was to use the model
to test several well-known theories of plant growth. The model was validated
against reported experiments on ryegrass, oat, a legume, and rutabaga, in which
dry matter yield was measured as a function of factorial application of N, P,
and K to the soil. The model shows that much of the deficient, optimal, toxic,
and interacitve response of plants to N, P, and K can be explained in terms of
strong linear response of cell chemistry to low nutrient concentrations and
inhibition by N, P, and K at high nutrient concentrations.
117
-------
76:03F-013
PHOSPHORUS-ZINC INTERACTION IN RELATION TO ABSORPTION RATES OP PHOSPHORUS, ZINC,
COPPER, MANGANESE, AND IRON IN CORN,
Safaya, N.M.
North Dakota University Project Reclamation, Grand Forks, North Dakota.
Soil Science Society of America Journal, Vol. 40, No. 5, p 719-722, September-
October 1976. 4 tab, 24 ref.
Descriptors: Nutrients, Fertilization, Phosphorus, Zinc, Copper, Manganese,
Iron, Corn, Crop production. Crop response.
The effects of P and Zn on growth , nutrient content in tops and roots, and the
rates of absorption of P, Zn, Cu, Mn, and Fe per unit fresh weight of roots for
two growth periods of corn were studied in soil culture under greenhouse condi-
tions. Visual symptoms of Zn deficiency appeared in plants when the level of
applied P was raised to 75 micro g P/g soil. Phosphate decreased tissue-Zn
concentration and Zn flux through roots. Zinc deficient plants had higher
concentration of P in their tissues. Phosphate flux was mostly reduced with Zn,
but during 27-48 days growth, Zn-supplied plants retained near identical rates of
P absorption (approximately 14 micro g/g fresh root/day) irrespective of the
level of P supplied. The rate of Cu absorption was reduced with both P and Zn
as the plants aged. Manganese flux was initially stimulated by P but later on
drastically reduced by Zn. Iron concentration in plants decreased with Zn
application but significant reduction in Fe flux with Zn occurred during early
growth of 25 ppm P-supplied plants only. In general, nutrient fluxes diminished
with plant age.
76:03F-014'
CALCIUM AND STRONTIUM ABSORPTION BY CORN ROOTS IN THE PRESENCE OF CHELATES,
Malzer, G.L., and Barber, S.A.
Minnesota University, Department of Soil Science, Minneapolis, Minnesota.
Soil Science Society of America Journal, Vol. 40, No. 5, p 727-731, September-
October 1976. 3 fig, 3 tab, 13 ref.
Descriptors: *Strontium *Calcium, Corn, Crop production, Absorption, Plant
growth.
While chelates have been shown to increase the flux of metal cations into roots,
the mechanism has been subject to question. The objective of this research was
to characterize the action of chelates on metal cation absorption. Calcium and
Sr rather than micronutrient metals were used because some plant roots do not
discriminate in their absorption, hence, relative flux of Ca vs. Sr could be used
to evaluate uptake mechanisms. The chelates used were EDTA, DTPA, and HEDTA.
Flux into corn roots was determined by monitoring Ca, Sr, and chelate depletion
from solution with time. Double labeling of Ca and Sr with Ca-45 and Sr-85 was
used. Ligand concentrations were measured using Cd titration, C-14-labeling,
and UV-absorption measurements of Cu-ligand complexes. Calcium and Sr were
removed from solution more rapidly than the chelate. Only 11 to 16% of the
chelating ligand was absorbed over a 5-day period, whereas 90% or more of each of
Ca and Sr was absorbed. The Ca/Sr ratio of uptake indicated that some of the
Ca and Sr was absorbed directly from the chelate. However, where Ca(2+) was
maintained by continual addition, chelated Ca appeared relatively unavailable
to the plant.
76:03F-015
EFFECTS OF BORON AND NITROGEN ON GRAIN YIELD AND BORON AND NITROGEN CONCENTRA-
TIONS OF BARLEY AND WHEAT,
Gupta, U.C., MacLeod, J.A., and Sterling, J.D.E.
Research Branch, Research Station, Agriculture Canada, Box 1210, Charlottetown,
Prince Edward Island, Canada.
Soil Science Society of America Journal, Vol. 40, No. 5, p 723-726, September-
October 1976. 5 tab, 12 ref.
Descriptors: Boron, Nitrogen, Wheat, Barley, Crop production. Crop response,
Grains (crops).
In field experiments, 4.48 kq B/ha added to soil decreased the grain yield of
118
-------
barley and wheat. Under greenhouse conditions, 0.5 ppm, added B reduced wheat
yields while 1.0 ppm added B reduced barley yields. The B toxicity in wheat in
1974 and barley and wheat in 1975 at 2.24 kg B/ha as associated with "educed
yield was alleviated somewhat by the additions of N to the soil in field experi-
ments, but the effect was riot significant, under greenhouse conditions, addition
of 50 ppm N or more reduced B uptake and alleviated B toxicity. In general the
B toxicity symptoms on the foliage under field conditions were associated with
> 11 ppm B in wheat boot stage tissue (BST) and > 14 ppm B in BST of barley
Added B increased the N concentration of grain where yields were decreased due
to B toxicity. Wheat yields increased with increased rates of N application
in all field experiments, while barley yields increased with increased rates of
N in 2 of the 3 years. In field experiments the highest B value was 34 ppm
Concentrations as high as 312 ppm B were found in greenhouse experiments. In
the presence of added B under greenhouse conditions, the barley tissue B concen-
tration was much lower when the moisture level near the fertilizer band was low
than when it was high.
76:03F-016
MODEL FOR PREDICTING EVAPOTRANSPIRATION FROM NATIVE RANGELANDS IN THE NORTHERN
GREAT PLAINS,
Hanson, C.L.
Agricultural Research Service, Northwest Watershed Research Center, Boise, Idaho.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 471-481, May-June 1976. 5 fig, 4 tab, 42 ref.
(See 76:020-004)
76:03F-017
PLANT WATER STRESS CRITERIA FOR IRRIGATION SCHEDULING,
Stegman, E.G., Schiele, L.H., and Bauer, A.
North Dakota state University, Department of Agricultural Engineering,
Fargo, North Dakota. ,
Presented at the 1975 Winter Meeting of the American Society of Agricultural
Engineers, December 15-18, 1975, Chicago, Illinois, 22p, 7 fig, 6 tab, 18 ref,
ASAE, Paper 75-2555.
(See 76:02G-075)
76:03F-018
UPWARD WATER MOVEMENT IN FIELD CORES,
Wells, L.G., and Skaggs, R.W.
Kentucky University, Department of Agricultural Engineering, Lexington, Kentucky.
Transactions of the American Society of Agricultural Engineers, Vol. 19,
No. 2, p 275-283, March-April, 1976, 12 fig, 3 tab, 29 ref.
Descriptors: *Groundwater movement, *Subsurface irrigation, *Cores, *Model
studies. Laboratory tests. Theoretical analysis, Hydraulic properties, Soil
properties, Soil profiles. Soil water movement, Design, Water table,
Equations, Irrigation, Pressure head, Moisture content, Boundaries (Surface),
Tensiometers, Hydraulic gradient, Hysteresis.
Subirrigation experiments were conducted under various initial and boundary
conditions using large, undisturbed cores from two field soils. The pressure
head distribution and flow volume were measured continuously, and the desorption
and imbibition character of the soil water were determined using pressure plates.
The effect of air entrapment on water content was determined gravimetrically,
while the hydraulic conductivity-pressure head relationship was determined for
each soil, from transient pressure head measurements during a drainage
event. An approximate model was developed to describe vertical water movement
during subirrigation. This model as well as the Richards equation were tested
against experimental results from both soils. Substantial variability was
evident in both measured soil properties and in water movement phenomena. The
approximate subirrigation model provided acceptable agreement with the obser-
vations. Consideration of soil stratification generally improved model
accuracy. For engineering design the added time and expense of sophisticated
models are not justified in comparison to the approximate model. Determination
of the total volume of stored water in a profile under specified boundary con-
ditions is essential to predictions of water movement.
-------
76:03F-019
A COMBINED MODEL FOR OPERATING IRRIGATED AGRICULTURAL SYSTEMS UNDER
UNCERTAINTIES,
Amir, I., Friedman, Y., Sharon, S., and Ben-David, A.
Technion-Israel Institute of Technology, Lowdermilk Faculty of Agricultural
Engineering, Haifa, Israel.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 2,
p 299-304, March-April 1976. 2 fig, 5 tab, 9 ref.
Descriptors: *Irrigation systems, Agriculture, *Planning, *Operations research,
*linear programming, *Simulation analysis, *Computer programs, Optimization,
Decision making, Monitoring, Cotton, Q theory, Hydraulics, Scheduling,
Constraints, Equations, Systems analysis, Mathematical models, *Risks.
Irrigation is a well-defined subsystem in a comprehensive agricultural pro-
duction system. Both of these systems are interrelated. An adaptable ad hoc
linear model has been found to be suitable for planning and operating the entire
system under uncertainties. This model is the framework of the irrigation sub-
system. Unfortunately, many of the factors involved in irrigation create non-
linear functions and thus cannot be directly included in the linear model. This
paper suggests using a linear model to (1) solve the overall system for optimal-
ity, (2) to check by a simulation technique whether the solution is feasible
and meets the irrigation system set-up and requirements, and (3) to change, if
necessary, one or both of the systems in order to achieve the best feasible
comprehensive solution. The combined model has been carried out for 89
possible different cotton activities of 430 ha, reflecting various irrigation
equipment and methods. The outcome provides a detailed irrigation timetable
and a list of the required parameters (pressure heads and discharges) for con-
trolling the hydraulic network as well as the optimal overall solution.
76:03F-020
SURFACE RESIDUE, WATER APPLICATION, AND SOIL TEXTURE EFFECTS ON WATER
ACCUMULATION,
Unger, P.W.
Agricultural Research Service, and Southwestern Great Plains Research Center,
Bushland, Texas.
Soil Science Society of America Journal, Vol. 40, No. 2, p 298-300, March-April
1976. 2 fig, 14 ref.
(See 76.-02G-078)
76:03F-021
VERTICAL FLOW OF AIR AND WATER WITH A FLUX BOUNDARY CONDITION,
McWhorter, D.B.
Colorado State University, Department of Agricultural Engineering, Fort
Collins, Colorado.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 2,
p 259-265, March-April 1976. 3 fig, 1 tab, 7 ref.
(See 76:02G-082)
76:03F-022
EROSION FOR CORN TILLAGE SYSTEMS,
Siemens, J.C., and Oschwald, W.R.
Illinois University, Department of Agricultural Engineering, Urbana-Champaign,
Illinois.
Transactions of the American Society of Agricultural Engineers, Vol. 19.- No. 1,
p 69-72, January-February 1976. 3 fig, 6 tab, 14 ref.
Descriptors: *Erosion control, *Cultivation, *Farm management, Crops, Corn
(Field), Rainfall, Simulated rainfall, Sediments, Nutrients, Runoff, Soil
erosion, Soil conservation. Agricultural runoff, Agricultural engineering,
Agriculture.
The erosion control effectiveness of six tillage-planting systems after planting
in corn residue was measured. The tillage systems utilized different types
and amounts of tillage in order to produce soil surfaces that varied in
120
-------
residue quantity and soil looseness in the tilled layer, A rainfall simulator
for application of simulated rain to plots was described. Conservation tillage
systems following corn such as chop-plant disk-chisel, coulter-chisel and
chisel can significantly reduce soil loss from that of fall plow After plant-
ing, these tillage systems have a greater impact on soil loss than on surface
runoff. The loss of N and P in surface runoff may not differ significantly
between tillage treatments, given the fertilizer application practices followed
by most Corn Belt crop producers. Conservation tillage systems can, however,
significantly influence the loss of total N and P as a result of the influence
on sediment removal. Total N and P loss may have little short-term influence,
but accumulated losses over time will eventually influence the need for N and
P fertilizers.
76:03F-023
NITROGEN FLUX INTO CORN ROOTS AS INFLUENCED BY SHOOT REQUIREMENT,
Edwards, J.H., and Barber, S.A.
Agricultural Research Service, Byron, Georgia.
Agronomy Journal, Vol. 68, No. 3, p 471-473, May-June 1976. 3 tab, 8 ref.
Descriptors: *Nitrogen, *Fertilizer, *Nutrient requirements, *Corn (Field),
*Root zone, Planting management, Plant growth, Absorption.
Experiments were conducted to determine the influence of shoot N requirements
on N unflux/M of corn roots. Trimmed- and split-root procedures were used for
solution culture experiments in the growth chamber to vary the N absorbing
roots/unit of shoot and assess the impact on N influx. Roots trimmed 2 days
before influx measurement had slight increases in the N influx/m of root,
causing reduced N uptake/plant. Roots split between N-containing and N-free
solutions from seedling stage until influx measurement at 16 or 18 days had
greater increases in net N influx than trimmed roots had. Both experiments
revealed no relation between N level within the root and N uptake rate/m of
root. Increased shoot demand for N does not immediately affect N influx into
the root, but N stress causes an increased influx capability. Plants develop-
ing throughout their growth cycle with N restricted to part of the root system
may absorb N more rapidly through those localized roots exposed to N than when
N is placed into the localized portion of soil after several weeks' growth.
76:03F-024
EFFECTS OF IRRIGATION REGIMES, PLANTING DATES, NITROGEN LEVELS, AND ROW SPACING
ON SAFFLOWER CULTIVARS,
Abel, G.H.
Agricultural Research Service, Phoenix, Arizona.
Agronomy Journal, Vol. 68, No. 3, p 448-451, May-June 1976. 8 tab, 7 ref.
Descriptors: Irrigation effects, *Planting management, *Nitrogen, *Fertili-
zation, *Crop response, Irrigation efficiency, Crop production, Arid lands,
Arizona, Water management (Applied), Water conservation.
In three experiments on safflower cultivars over a 3-year period, seed yields
were greater in the last two years with crops planted on December 15 than those
planted February 15. Plants in two-row plots produced fewer seeds/head and
smaller seeds than those in one-row plots, but increased populations in the
former group compensated for such deficiencies and the yields were comparable.
An irrigation regime involving early cut-off conserved water and labor, reduced
weed growth, and produced optimum seed yields at lower levels of nitrogen
fertilization. The best fertilization levels were from 84 to 336 kg/ha, accord-
ing to the planting date, irrigation regime, and cultivar. For the Laveen clay
loam soil at the test site (Mesa, Arizona) , 168 kg/ha was optimum for a Decem-
ber planting; quantities exceeding 84 kg/ha had no yield advantage with a Feb-
ruary planting. The "Dart" cultuvar outyielded all others used, especially
when given the optimum fertilization and irrigation treatment.
76:03F-025
SOIL WATER UPTAKE BY ALFALFA,
Khol, R.A., and Kolar, J.J.
Agricultural Research Service, Kimberly, Idaho, Snake River Conservation
121
-------
Research Center.
Agronomy Journal, Vol. 68, No. 3, p 536-538, May-June 1976. 4 fig, 14 ref.
Descriptors: *Soil water movement, Soil water, *Moisture uptake, *Alfalfa,
*Soil-water-plant relationships, Root zone, Xylem, Soil profiles, Moisture
stress.
Soil water uptake by alfalfa was studied by monitoring a seed crop with a
neutron moisture probe. Plant water potential measurements support passive
uptake. Water was withdrawn in the lower root zone, where soil matric potential
tials were between -7 and -10 bars, while the upper portion of the profile was
above -2 bars. Results indicate that passive water uptake requires large water
potential differences between the root xylem and soil in the moist upper portion
of the profile. Alfalfa plant moisture potentials decreased through the grow-
ing season, possibly due 'to moisture stress and maturity. While water is
preferentially taken up from layers where the soil water potential is high, it
continues being withdrawn from layers of lower potential. Root location
(shallow or deep) does not appear to influence water uptake.
76:03F-026
CORN PLANT WATER STRESS AS INFLUENCED BY CHISELING, IRRIGATION, AND WATER
TABLE DEPTH,
Reicosky, D.C., Campbell, R.B., and Doty, C.W.
Agricultural Research Service, Coastal Plains Soil and Water Conservation
Research Center, Florence, South Carolina.
Agronomy Journal, Vol. 68, No. 3, p 499-503, May-June 1976. 5 fig, 3 tab,
7 ref.
Descriptors: *Corn (Field), *Water table, *Soil-water-plant relationships,
Crop production, Soil management, Crop response, *Irrigation effects, Stomata,
Cultivation, Moisture stress, *Chiseling.
Chiseling and irrigation effects on plant water status were evaluated through
leaf water potential, stem diameter and stomatal resistance measurements. Corn
grown on a Varina sandy loam chiseled to 38 cm was compared with that grown on
conventionally tilled plots. Chiseling had no effect on daily minimum leaf
water potential the first year (1972) and only a slight effect on stomatal
resistance, but irrigating had some beneficial effect. At tasseling in 1973,
with a water table 80 cm from the surface, chiseling produced deeper-rooted
corn that allowed water utilization in the capillary fringe above the water
table; leaf water potential increased slightly while stomatal resistance and
stem diameter fluctuation decreased. Plant-water status on chiseled plots was
similar to that on furrow-irrigated plots. Improved midday plant water status
caused an 8-metric ton/ha increase in corn ear yields. Results indicate that
chiseling of soils with root restricting layers can increase corn production,
especially when the water table is about 80 cm from the surface tasseling.
76:03F-027
FERTILIZATION, NUTRIENT COMPOSITION, AND YIELD RELATIONSHIPS IN IRRIGATED
SPRING WHEAT,
Gardner, B.R., and Jackson, E.B.
Arizona Agricultural Experiment Station, Department of Soils, Water, Engineer-
ing and Plant Sciences.
Agronomy Journal, Vol. 68, No. 1, p 75-78, January-February 1976. 3 fig,
5 tab, 5 ref.
Descriptors: *Nitrates, *Fertilization, *Crop response, *Nutrient require-
ments, *Wheat, Arizona, Root zone, Crop production, Testing procedures.
Plant tissues, Phosphates.
The effect of N fertilization on the growth and yield of semidwarf spring
wheat in the Yuma Valley of southwestern Arizona and a tissue test as guide
for applying such fertilizers is presented. Excessive N used is evaluated, in
two field experiments reduced yields slightly when compared with sufficient N
levels. Application of 336 kg N/ha produced the best yields, with no further
increase resulting from higher rates. Yields intermediate between control and
high-yield results were achieved with 112 and 224 kg/ha rates prior to planting;
122
-------
similar results at those two rates suggest much of the N applied preplant was
leached from the root zone. N caused increases in number of heads/unit area
and seeds/head, with a.decrease in the weight of individual seeds Total N
content in the grain increased with larger N applications. Determination of
P in the lower portion of wheat stems was of doubtful value in determining the
crop's P status. ^
76:03F-028
IRRIGATION SYSTEMS IN TAIWAN: MANAGEMENT OF A DECENTRALIZED PUBLIC ENTERPRISE
Abel, M.E. '
Minnesota University, Department of Agricultural and Applied Economics, Saint
Paul, Minnesota.
Water Resources Research, Vol. 12, No. 3, p 341-343, June 1976. 1 fig, 1 tab,
22 ref.
Descriptors: Irrigation systems, *Canals, *Management, Irrigation efficiency
Water resources, Planning, Operations, Agriculture, Water policy, Engineering,
Agronomy, Legal aspects. Administration, Rice, Water utilization.
The efficiency of the management of irrigation systems in Taiwan, viewed as
decentralized public enterprises, depends on four interrelated factors; (1)
the recognition that water is a scarce factor in agricultural production; (2)
the legal administrative basis for centralized planning of irrigation invest-
ments but decentralized management of irrigation systems; (3) the information
systems which permit the exchange of agronomic and engineering information
between the users of water and the managers of irrigation systems; and (4) the
use of incentive structures for both the managers of irrigation systems and the
users of water that appear to be compatible with the efficient use of water
within the irrigation system. Discussed also is the true complexity of irri-
gation systems and irrigated crop production found in Taiwan today with which
the management of these systems must contend.
76:03F-029
WEATHER-DEPENDENT PRICING FOR WATER RESOURCES IN THE TEXAS HIGH PLAINS,
Lane, M.N., and Littlechild, S.C.
International Bank for Reconstruction and Development, Washington, D.C.
Water Resources Research, Vol. 12, No. 4, p 599-605, August 1976. 4 tab,
9 ref.
Descriptors: *Irrigation water, *Pricing, *Linear programming, Optimization,
Weather, Reservoirs, Water supply, Farms, Profit, Crops, Constraints, Costs,
Rainfall, Equations, Mathematical models, Systems analysis.
Two alternative schemes for pricing irrigation water are examined. Under the
first scheme, price is independent of weather; in the second scheme, price
varies with weather so as to generate just enough demand to exhaust reservoir
capacity. The second scheme provides savings through the more efficient utili-
zation of available reservoir supplies and through the curtailing of demand so
as to allow the construction of smaller reservoirs. The analysis proceeds by
means of a linear programming under uncertainty model of a representative farm.
The model is applied to the High Plains of Texas. Results suggest that the
weather-dependent pricing scheme would increase farm profits by the order of
10% per annum.
76:03F-030
OPTIMIZATION OF CROP IRRIGATION STRATEGY UNDER A STOCHASTIC WEATHER REGIME:
A SIMULATION STUDY,
Ahmed, J., van Bavel, C.H.M., and Hiler, E.A.
Water Resources Research, Vol. 12, No. 6, p 1241-1247, December 1976. 5 fig,
2 tab, 26 ref.
Descriptors: *Irrigation efficiency, *Crop response, *Water utilization,
*Simulation analysis, Optimization, Crops, Decision making, Weather, Texas,
Sorghum, Soil, Atmosphere, Water resources, Management, Agriculture, Computer
models, Equations, Operations research, Irrigation water, Water policy.
Conservation.
123
-------
A dynamic simulation model of the soil-water-atmosphere-plant system is
developed as a tool for irrigation decision making under a stochastic weather
regime and when water supplies are limited. Crop yield, foliage development,
plant water deficits, and irrigation decisions have been treated as inter-
dependent processes. Yield susceptibility of the crop to water deficit is a
function of crop growth stage. The stomatal regulation of transpiration by the
crop has been accounted for as well. The model is a closed loop dynamic system,
in which past irrigation decisions and weather conditions affect the current as
well as the future response of the crop system, and consequently, the future
irrigation decisions and the overall water use efficiency. Determined are the
optimal irrigation timing and quantities; estimated are the associated yields,
the water use efficiencies, and the trade-offs between water conservation and
crop yield. The crop growth and yield simulation consists of two parts: (1)
a dynamic crop growth and plant behavior model under stochastic weather regime
and specific irrigation strategy; and (2) a seasonal crop stress computation
for the simulated crop with associated yield estimates. The optimization
criteria, water use efficiency, is defined as the ratio of crop yield to total
amount of irrigation water used in its production. Specific illustration is
given by considering grain sorghum grown under weather conditions typical for
south central Texas.
76:03F-031
POTASSIUM SOURCES AND AVAILABILITY ON A DEEP, SANDY SOIL OF EAST TEXAS,
Hons, F.M., Dixon, J.B., and Matocha, J.E.
Texas A and M University, Department of Soil Mineralogy, College Station,
Texas.
Soil Science Society of America Journal, Vol. 40, No. 3, p 370-373, May-June
1976. 2 fig, 4 tab, 28 ref.
Descriptors: *Potassium, Nutrients, Soil properties, Bermuda grass, Soil
investigations, Soil profiles, Fertilization, Root development.
Soil properties were assessed that may have contributed to the failure of
Coastal bermudagrass to respond to application of K on Darco fine sand for 5
consecutive years. The depth to which plant roots absorbed K was assessed by
field observation and by determination of K levels in control and treatment
plots. Potassium minerals were determined by chemical methods to assess poten-
tial nutrient sources. Potassium removal was indicated to at least 160 cm by
soil solution content and to 235 cm by exchangeable K concentration and Gapon
selectivity values. Depth of bermudagrass rooting was in agreement with chemi-
cal indicators of K removal.
76:03F-032
GASEOUS LOSS OF AMMONIA FROM SULFUR-COATED UREA, AMMONIUM SULFATE, AND UREA
APPLIED TO CALCAREOUS SOIL (PH 7.3),
Prasad, M.
M.J. Woods and Associates, 13 Kilbarrack Grove, Dublin, 5, Ireland.
Soil Science Society of America Journal, Vol. 40, No. 1, p 130-134, January-
February 1976. 7 tab, 20 ref.
Descriptors: Urea, Nitrogen, Temperature, Calcareous soil, Soil moisture,
Ammonia, Nutrients.
Laboratory incubation experiments were conducted to study the comparative
volatilization loss of NH3 in a calcareous soil from sulfur-coated urea (SCU)
with fast (F), medium (M), and slow (S) dissolution rates, ammonium sulfate
(AS) and urea, at two temperatures 22 and 32C, and at three soil moisture
levels 25, 50, and 80% of the water holding capacity of the soil. The effect
of the addition of organic amendment (filter press mud) to soil on NH3 loss
from these N-sources was also studied. Loss were studied up to 21 days. At
both temperatures increasing soil moisture levels led to reduction of NH3 loss
regardless of the N-source, despite the fact that the soil analysis showed
higher dissolution of N from SCU at high soil moisture.
124
-------
76:03F-033
HIGH-FREQUENCY IRRIGATION FOR WATER NUTRIENT MANAGEMENT IN HUMID REGIONS
Phene, C.J., and Beale, O.W. '
United States Department of Agriculture, Coastal Plains Soil and Water
Conservation Research Center, Southern Region, Florence, South Carolina
C«e??e S?CieuY ?! *™*rica Jo^nal, Vol. 40, No. 3, p 430-436, May- June
o fig, 2 tab, 16 ref.
Descriptors: Subsurface irrigation, Irrigation systems, Irrigation, Irrigation
effects, Nutrients, Humid climates, Humid areas, Soil water, Fertilization
Crop response. Corn, Furrow irrigation, Sprinkler irrigation, Leaching.
A water-nutrient management method was designed to prevent plant-water and
nutrient stresses while maximizing the available soil water storage to accomo-
date rainfall. This method minimized the need for the soil as a storage
reservoir for water and nutrients by frequently irrigating a portion of the
root zone with small amounts of water and nutrients. The optimal range of soil
matric potential, based on soil oxygen diffusion rate, soil strength, water
desorption characteristics, and unsaturated hydraulic conductivity was used
to determine high-frequency irrigation criteria for sweet corn. Trickle-
irrigated plots yielded 12 and 14% more corn than did the furrow-and sprinkler-
irrigated plots. When fertilizers were broadcast and banded, soil N03-N
profiles measured near the end of the growing season showd that, compared to
furrow and sprinkler irrigation, trickle irrigation reduced N03-N losses from
the root zone.
76:03F-034
THE EFFECTIVENESS OF A MIST VERSUS A LOW PRESSURE SPRINKLER SYSTEM FOR BLOOM
DELAY,
Wolfe, J.W., Lombard, P.B., and Tabor, M.
Oregon State University, Southern Oregon Experiment Station, Department of
Agricultural Engineering, Corvallis, Oregon.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 510-513, Special Edition 1976. 4 fig, 2 tab, 7 ref.
Descriptors: *Orchards, Oregon, Sprinkler irrigation, Sprinkling, Irrigation
effects, Irrigation practices, Irrigation.
This paper deals primarily with tests made on a fogging or misting system
installed for bloom delay in a pear orchard at Medford, in comparison with a
system using small sprinklers. Conclusions include: 1. A misting system
provided greater cooling for bloom delay than a low-pressure sprinkler system
when the water application rate was about 3 1/s ha (19 gpm per acre). 2. A
bloom delay, of 11 days was observed in Bartlett trees and 9 days in Bosc under
the mist system tested during a late season. To obtain more delay during an
early season would likely require running the system more hours . 3 . The mist
. system required only about 60 percent as much water per day of delay as the
sprinklers did. 4. A mist-system capacity of 3 1/s ha provided almost as
many degrees of cooling on a day when the maximum air temperature was 10. 6C
(51F) as on a much warmer day, suggesting that the cooling efficiency for this
system had nearly reached its maximum at 10. 6C (51F) . 5. The mist system is
easier to install on established hedgerows than on large trees and appears to
function at least as well as many permanent overhead sprinkler systems used for
frost control by encasing the trees in ice. 7. More research is needed to
develop criteria for an economical system design for mist including determin-
ing the minimum required system capacity, the optimum (minimum) pressure
required for adequate breakup of drops, a satisfactory filtration system,
and the least elaborate layout for placing the mist uniformly on the trees.
AN "EVALUATION OF SULFUR-COATED UREA AS A PREPLAN? TOTAL SEASON NITROGEN SUPPLY
FOR TRELLISED TOMATOES,
Shelton, J.E. , . .
-North Carolina State University, Department of Soil Science, Raleigh,
SoilhSciencenSociety of America Journal, Vol. 40, No. 1, P 126-129, January-
125
-------
February 1976. 2 fig, 2 tab, 5 ref.
Descriptors: *Urea, Nitrogen, Nutrients, Fertilization, Tomatoes, Crop
response, Sampling, Crop production.
The use of a controlled release N source for the production of trellised
tomatoes which require frequent topdressings would be desirable. Three sulfur-
coated urea (SCU) materials having release rates of 11.4, 21.5, and 29.3% over
a 7-day period were compared to NH4N03 applied preplant or as multiple appli-
cations. Nitrogen rates were 392,560 , and 729 kg N/ha. Marketable yields
from an application of SCU(11.4) at 392 or 560 kg N/ha were greater than with
the same rate of N as NH4N03 either as preplant or split applications. When
SCU(21.5) or SCU(29.3) was used, the yields were comparable to a single
application of NH4N03. Differences in fruit number per plot were not signifi-
cantly related to treatments. However, there was a significant difference in
average fruit weight which was correlated with total yield. Tissue N content
was highest at the first sampling from a single application of NH4N03 and
lowest from SCU(11.4). However, at later sampling periods the N content was
maintained at a higher level with SCU(11.4). Although 729 kg N/ha as a single
application of NH4NO3 detrimentally affected plant growth and production, this
effect was not noted with the sulfur-coated materials.
76:03F-036
INFLUENCE OF ROW SPACING AND STRAW MULCH ON FIRST STAGE DRYING,
Adams, J.E., Arkin, G.F., and Ritchie, J.T.
Agricultural Research Service, United States Department of Agriculture,
Southern Region, Temple, Texas.
Soil Science Society of America Journal, Vol. 40, No. 3, p 436-442, May-June
1976. 10 fig, 2 tab, 14 ref.
Descriptors: Evaporation, Grain sorghum, Drying, Plant populations, Mulching,
Crop production, Crop response.
Evaporation during first stage drying was measured with evaporation plates on
the soil surface in grain sorghum plots with 25-, 50-, and 100-cm row spacings,
during several stages of grain sorghum development in 1972 and 1973. Evapor-
ation during first stage drying was affected by row spacing, leaf area index
(LAI), and soil shading. Both LAI and soil shading were related to row spacing
and plant population. The more complete plant canopy of grain sorghum with
narrow-row spacing decreased penetration of radiant energy to the soil surface
and reduced the evaporation rate of soil water during first stage drying.
Evaporation was greatest during the early part of the season when shading was
least and lowest during boot stage and pollination, when all leaves were
fully expanded and provided maximum plant canopy and soil shading. Narrow-
row spacing established an earlier, and more complete plant canopy than conven-
tional 100-cm row spacing and shaded more of the soil surface from early vegeta-
tive growth to maturity- Soil surafce shaded near solar noon was a better
indicator of first stage evaporation beneath a canopy than LAI. The combined
effect of a mulched surface and a plant canopy on reducing evaporation was the
product of the fractional reduction in potential mulched surface with no
canopy cover. An empirical equation was developed from the evaporation data
for use in calculating first stage evaporation as related to potential evapor-
ation, fraction of the soil surface shaded, and mulch rate.
76:03F-037
DEEP PERCOLATION IN A FURROW-IRRIGATED SANDY SOIL,
Linderman, C.L., Mielke, L.N., and Schuman, G.E.
Agricultural Research Service, United States Department of Agriculture,
Department of Agricultural Engineering, Nebraska University, Lincoln,
Nebraska.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 250-253, Special Edition 1976. 6 fig, 1 tab, 20 ref.
Descriptors: *Deep percolation, *Furrow irrigation, Sands, Irrigation,
Irrigation effects, Fertilization.
126
-------
irrigating sandy soils with shallow water tables creates a potential for deep
percolation losses of water and nitrogen and consequently, nitrate pollution
of groundwater The amount and nitrate content of percolate was measured with
eight vacuum extractors buried below the root zone in a sandy, furrow-irrigated
cornfield. Total irrigation-season percolation was 17.6 cm, which was 25 per-
cent of the water leaving the root zone. The maximum percolation rate was over
0.37 cm/day when the corn root system was not yet fully developed and when
heavy rainfall followed irrigating. More frequent irrigations with smaller
amounts of water should reduce percolation. Percolation of nitrate-nitrogen
was 2.5 kg/ha/cm of percolate when N (67 kg/ha) was applied in solution in the
irrigation water and 3.0 kg/ha/cm of percolate when anhydrous ammonia N (90 kg/
ha) was sidedressed. Percolation of nitrate-nitrogen was affected more by total
deep percolation of water than by the method of fertilizer application.
76:03F-038
A WATER SPRINKLER FOR ARBITRARILY SHAPED AREAS,
Burgdorf, 0., and Henderson, J.M.
Westinghouse Electric Corporation, Sunnyvale, California.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 704-707, Special Edition 1976. 9 fig, 2 tab, 2 ref.
Descriptors: Sprinkling, Sprinkler irrigation. Irrigation, Irrigation systems,
Irrigation practices, Winds, Uniformity coefficient.
The concept of watering arbitrary areas from a single moving nozzle shows
reasonable promise. The average 28 percent distribution error reflects an
acceptable trade-off required to gain a 13.72 m (45 ft) range capability with
0.172 HPa (25 psi) water pressure. This project has given visibility to
factors important to the continuation of design of sprinklers for watering
arbitrarily shaped areas: 1. ' trade-off considerations between coherent flow
(low range, harsh water impact and high uniformity); 2. kinematic limitations
inherent in simple devices which depend solely on water pressure for system
motion and control; 3. wind influence; 4. mechanisms for perimeter specifi-
cation; and 5. optimization techniques which allow synthesis of control mech-
anisms for best available distributions. The concept offers potential for
certain agricultural applications. For example, adjacent square patterns could
prove more cost effective than overlapping rotational systems. It is necessary
to seek alternate designs which keep the nozzle (or nozzles) at relatively low
elevation angles to minimize wind effects.
76:03F-039
EFFECTIVE PRECIPITATION OF VARIOUS APPLICATION DEPTHS,
Heermann, D.F., and Shull, H.H.
Agricultural Research Service, United States Department of Agriculture,
Department of Agricultural Engineering, Fort Collins, Colorado.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 708-712, Special Edition 1976. 8 fig, 3 tab, 21 ref.
Descriptors: Lysimeters, Rainfall, Rain, Evapotranspiration, Water require-
ments. Crop production.
Irrigators have always questioned how effective small rains and light irri-
gations are in meeting crop water requirements. Data from precision weighing
lysimeters indicated that very small rains offset the normal water use by the
plants and, therefore, very effectively meet crop water requirements.
76:03F-040
CALCULATING EVAPORATION FROM NATIVE GRASSLAND WATERSHEDS,
Ritchie, J.T., Rhoades, E.D., and Richardson, C.W. Oo-,,i-0
United Stated Department of Agriculture, Agricultural Research Service,
Department of Soil Science, Temple, Texas. ,,,•-,.., *™ i and water
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 1098-1103, Special Edition 1976. 5 fig, 1 tab, 17 ret.
Descriptors: *Evapotranspiration, Evaporation, Grassland, Computer model, Model
studies, Transpiration, Soil water, Soil moisture.
127
-------
Evaporation from soil and plant surfaces in many natural grassland sites will
often be less than potential evaporation because of sparse vegetation or soil
water deficits in the root zone. A computer model developed for calculating
daily evaporation from row crop surfaces with partial cover was modified for use
on native grasslands. Daily evaporation is computed by adding independently
calculated soil evaporation and transpiration. Potential evaporation is
calculated from commonly available atmospheric information. Soil evaporation rate
is related to soil hydraulic properties, mulch cover, and potential evaporation
rate. Transpiration rate is related to potential evaporation through the green
leaf area index and the soil water status of the root zone. Daily evaporation
was calculated for three small native grassland watersheds where runoff, rainfall,
and soil water content were measured. Seasonal changes in soil water content were
calculated based on drainage rates computed from the amount of infiltration in
excess of the upper limit of extractable soil water and calculated evaporation
rates. Calculated changes were usually within + 5 cm of measured soil water
during a 1-year period.
76:03F-041
MULCH, NITROGEN, AND IRRIGATION EFFECTS ON GROWTH, YIELD, AND NUTRIENT UPTAKE OF
FORAGE CORN,
Khera, K.L., Khera, R., Prihar, S.S., Sandhu, B.S., and Sandhu, K.S.
Punjab Agricultural University, Department of Soils, Ludhiana, India.
Agronomy Journal, Vol. 68, No. 6, p 937-941, November-December 1976. 5 fig,
6 tab, 17 ref.
Descriptors: Mulching, Nitrogen, Irrigation effects, Crop response. Nutrients,
Temperature, Soil temperature, Crop production, Corn.
Nitrogen, irrigation, and soil-temperature regime are major factors influencing
crop growth. Hot season crops in tropical areas are reported to benefit from
soil temperature reductions caused by straw mulching. But how the mulch would
affect the nitrogen and irrigation requirements of the crop is not known. The
independent and combined effects of two rates of straw mulch, viz., 0 and 6 metric
tone/ha; three rates of nitrogen, viz., 50, 100, and 150 kg N/ha; and three
levels of irrigation, viz., 7.5 cm irrigations based on irrigation water (IW)/pan-
evaporation (PAN-E) ratios of 0.6, 0.9, and 1.2 on forage corn in a 2-year field
experiment were studied. Green and dry forage yields and uptake of N and P
significantly increased with mulching and with each successive increment of
nitrogen. As the IW/PE ratio increased from 0.6 to 0.9, the green and dry forage
yields and nutrient uptake increased significantly, but declined with further
increase in irrigation. As a 2-year average, mulching increased the dry forage
yield by 11.8 quintals/ha or 26 percent and showed a significant interaction with
nitrogen rates. Fifty kg and 100 kg N/ha with mulch yielded as much as 100 kg
and 150 kg N/ha without mulch, respectively. It is indicated that straw mulching
in forage corn during hot and dry season increases yield and nutrient uptake and
helps economize nitrogen.
76:03F-042
GROWTH RATE AND NUTRIENT UPTAKE OF TWO COTTON CULTIVARS GROWN UNDER IRRIGATION,
Halevy, J.
The Volcani Center, Agricultural Research Organization, Bet Daga, Israel.
Agronomy Journal, Vol. 68, No. 5, p 701-705, September-October 1976. 2 fig,
3 tab, 22 ref.
Descriptors: *Cotton, Irrigation, Irrigation practices. Crop response. Nutrients,
Nitrogen, Phosphorus, Potassium, Semi arid climates.
The production of high cotton yield is highly dependent on adequate growth rate
and nutrient uptake about which relatively little information is available under
semiarid conditions. Growth rate and N, P, K uptake of two cotton cultivars,
"Ada 1517-C" and "Acala 4-42," which differ in their response to K fertilizer,
were investigated in an irrigated field under favorable conditions conducive to
high yields. The rate of dry matter production was slow unitl flowering and
after the first bolls opened. Up to 72 days from emergence, 15 percent of the
total dry matter was produced; from 112 days until picking, 10 percent; and
during the 40-day period to 72 to 112 days, 75 percent. Throughout this period
the growth rate was nearly linear, 250 kg/ha/day. Total dry matter was 12,200
128
-------
to 13,480 kg/ha. Its distribution in mature plants was 26 percent in the leaves,
24 Percent in stems 16 percent in burs, 21 percent in seeds, and 13 percent in
lint. The lint yield was 1,700 kg/ha. Total uptake of N, P, and K was 230 45
and 174 kg/ha. The total uptake of N and P followed that of dry matter production,
whereas K was absorbed more rapidly, reaching a maximum at 112 days from emergence
and then decreasing. The removal of nutrients from the field by seed and lint was
98 to 109 kg N/ha, 19 to 21 kg P/ha, and 43 to 47 kg K/ha.
76:03F-043
REDUCING TAILWATER RUNOFF FOR EFFICIENT IRRIGATION WATER USE,
Schneider, A.D., New, L.L., and Musick, J.T.
United States Department of Agriculture, Southwestern Great Plains Research Center
Department of Agricultural Engineering, Bushland, Texas. '
Transactions of the American Society of Agricultural Engineers, Soil and Water
p 1093-1097, Special Edition 1976. 4 fig, 3 tab, 8 ref.
Descriptors: *Tailwater return flow, Irrigation, Irrigation practices. Furrow
irrigation. Surface irrigation, Grain sorghum. Crop production, Crop response.
Tailwater runoff from 570-m graded furrows was varied from 0 to 8 hr to determine
the variability of grain sorghum yield with length of run. During the first 3 to
4 hours, cumulative infiltration into the Pullman clay loam is 5 to 7 cm.
Infiltration into the slowly permeable soil then approaches the steady-state rate
of less than 0.25 cm/hr. Continuing to irrigate after the entire furrow reached
the steady-state infiltration rate did not significantly increase the field
average yield. The root zone at the tail end of the field was not fully wetted,
but the soil water was sufficient for normal plant growth, and tailwater runoff
was less than 10 percent of the applied water. As a result, the irrigation water-
use efficiency varied inversely as the duration of tailwater runoff. By reducing
the duration of tailwater runoff, additional land could be irrigated with the
limited groundwater supply.
76:03F-044
AN ASPHALT INCORPORATOR AND PACKER FOR LINING IRRIGATION DITCHES,
McLaughlin, N.B., Dyck, F.B., and Sommerfeldt, T.G.
Agriculture Canada, Research Station, Research Branch, Swift Current,
Saskatchewan, Canada.
Transactions of the American Society cf Agricultural Engineers, Soil and Water,
p 1085-1088, Special Edition 1976. 7 fig, 1 ref.
Descriptors: *Channel improvement, *Asphalt, *Linings, Irrigation, Irrigation
systems. Ditches.
In laboratory experiments, an asphalt emulsion mixed with soil has shown promise
of being a suitable lining material for irrigation ditches. Prototype machinery
developed for lining a field lateral with the mixture in order that it may be
evaluated under field conditions is duscussed. The incorporator is a large
rototiller with a double-cone rotor whose longitudinal section conforms to the
ditch cross section. The rototilling action mixes asphalt with the upper 8 cm
of soil in the ditch profile. The packer is a large double-con roller with a
longitudinal section that also conforms to the ditch cross section. Operation
of the two machines in the field is discussed.
76:03F-045
AGRICULTURAL DRAINAGE WATER AS A BASIS FOR WILDLIFE DEVELOPMENT IN THE SAN JOAQUIN
VALLEY OF CALIFORNIA,
Dickey, G.L., Rivera, R.A., Hewes, B.J-, and Sussman, M.W.
United States Department of Agriculture, Soil Conservation Service, Department
of Civil Engineering, Davis, California.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 862-865, Special Edition 1976. 3 fig, 3 tab, 15 ref.
Descriptors: *Drainage, *Drainage water, *Marshes, Drainage effects, California,
Return flow. Wildlife habitat, Wildlife management.
129
-------
Important marshland habitat in California is estimated at 1.94 million ha (4.8
million acres) with State and Federal ownership totaling about 93,555 ha (231,000
acres). Some of the habitat area has a partial water supply, some a full supply,
but much of it has very little water. Agricultural drainage could provide a full
water supply for up to 127,170 ha (314,000 acres) of wildlife habitat by the year
2000. The impact of such usage would be greatly beneficial both to wildlife
habitat development and to irrigated cropland. Agricultural drainage can provide
a firm water supply for wildlife and the wildlife use will allow the development
of on-farm drainage systems to maintain land productivity. Further, such a short-
term plan would be easily adaptable and in fact complementary to a long term plan
for a master drainage system to be implemented at a later date.
76:03F-046
EFFECT OF P, CA, AND MG CONCENTRATIONS IN SOLUTION CULTURE ON GROWTH AND UPTAKE
OF THESE IONS BY RICE,
Fageria, N.K.
National Research Center for Rice and Beans, Caiza Postal 179, Goiania-Goias,
Brazil.
Agronomy Journal, Vol. 68, No. 5, p 726-732, September-October 1976. 5 fig,
3 tab, 28 ref.
Descriptors: Fertilization, Fertilizer, Nutrients, Phosphorus, Calcium,
Magnesium, Rice, Crop response, Crop production.
Nutrient requirements during various phases of plant growth are affected by many
factors. Greater knowledge of this subject is warranted by the intensification
of agriculture. The present study was undertaken to determine the effect of
varying concentrations of P, Ca, and Mg on the growth and uptake patterns of
these ions by rice. Rice plants were grown in culture solution of these ions.
Minimum concentrations required for maximum growth were 25 microM P, 250 microM
Ca, and 33 microM Mg, respectively. At higher P concentrations a linear
absorption isotherm was obtained with respect to P content in the plant tissue.
The critical concentration of P in the tops of 100-day old plants was 0.4 percent.
To support maximum growth, Ca content varied from 242 to 2,373 micro g-atoms/five
plants for 25 to 125 days of growth. Maximum growth was characterized by a
relative absorption (I(M)) rate ranging from 14 to 320 micro g-atoms of Ca/g dry
weight of roots/day during the period of cultivation. To support maximum growth,
plants must absorb 13.7, 7.7, 4.3, 4.0, and 2.4 micro g of magnesium per g fresh
weight of roots/hour at 25, 50, 75, and 100, and 125 days of growth, respectively.
With the advancement of age, P and Ca content in plants and their utilization
quotients were increased but relative growth rate and rate of Ca and Mg
absorption decreased.
76:03F-047
IRRIGATION CONTROL USING TENSIOMETERS AND SALINITY SENSORS,
Oster, J.D., Willardson, L.S., van Schilfgaarde, J., and Goertzen, J.O.
Agricultural Research Service, United States Department of Agriculture,
Department of Soil Science, Riverside, California.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 294-298, Special Edition 1976. 5 fig, 1 tab, 24 ref.
Descriptors: Irrigation practices. Irrigation, Leaching, Tensiometers,
Lysimeters, Evapotranspiration, Root systems.
Pressurized, high-frequency irrigation systems can be controlled to provide a
nearly constant prescribed leaching fraction by use of salt sensors and
tensiometers in combination as a dual feedback system. A lysimeter experiment
evaluated the optimum depth of sensor placement and provided experience for the
appropriate selection of control settings, both of which are strongly dependent
on root water uptake distribution.
76:03F-048
TRAVELING GUN APPLICATION UNIFORMITY IN HIGH WINDS,
Shull, H., and Dylla, A.S.
Agricultural Research Service, United States Department of Agriculture, North
Central Region, Department of Agricultural Engineering, Morris, Minnesota.
130
-------
Field tests of a traveling gun sprinkler irrigation system showed that increases
in wind yleocity must be accompanied by decreases in travel lane spacing if an
acceptable water application uniformity is to be maintained. Travel lane spacing
must be decreased further as the wind direction and travel direction become more
nearly parallel. An empirical equation is presented to estimate lane spacing as
a function of wind velocity and direction, and sprinkler water pressure, for the
sprinkler tested. If travel lane spacings recommended for no-wind conditions
are used, the water distribution pattern during winds will become uneven, if
recommended lane spacing reductions for windy conditions are followed, the
application pattern during winds may be acceptable under some wind directions-
however, if winds are nearly parallel to the travel direction the application
pattern will be poor. Also, if the narrower spacings recommended for winds are
used, the application pattern may be poor if the wind velocity decreases.
Spacings from 30 to 75 percent of the wetted diameter gave acceptable uniformity
with no wind.
76:03F-049
ANATOMICAL RESPONSE OF POTATO STEMS AND ROOTS TO SOIL MOISTURE AND RATES OF
FERTILIZER,
Singh, G., and Struchtemeyer, R.A.
Maine University, Department of Soils, Orono, Maine, 04473.
Agronomy Journal, Vol. 68, No". 5, p 732-735, September-October 1976. 4 tab,
14 ref.
Descriptors: Soil moisture, Soil water, Fertilizer, Fertilization, Nutrients,
Potato, Nitrogen, Moisture stress, Root development, Xylem.
This study was conducted to determine the effect of three moisture regimes and
three rates of fertilizer on the anatomy of stems and roots of the "Katahdin"
cultivar of potato. A Caribou loam (coarse loamy, mixed frigid Dystric
Eutrochrept) was used in a greenhouse experiment. The soil was placed in pots.
Fertilizer at rates of 0, 168, and 336 kg N/ha, in a 10-15-15 mixture, was used.
Soil moisture stresses equivalent to 30, 50, and 70 percent depeletions of
available moisture were allowed to develop. The data showed that the area of
the xylem in the stems decreased as soil moisture stress increased. The highest
rate of fertilizer reduced the area of the xylem, but increased the diamter of
the individual vessels. In the roots the area of xylem and phloem decreased
while the area of cortex increased with an increase to soil moisture stress in
the 75-day experiment. The area of xylem tended to increase while the cortical
tissue tended to decrease with increases in the rate of fertilization.
76:03F-050
NEMATICIDE APPLICATION THROUGH POROUS SUBSURFACE IRRIGATION TUBING,
Chesness, J.L., Dryden, J.R., and Brady, U.E. Jr.
Georgia University, Department of Agricultural Engineering, Athens, Georgia.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 105-107, Special Edition 1976. 6 fig, 5 ref.
Descriptors: *Nematocides, *Nematodes, Subsurface irrigation, Irrigation prac-
-tices, Irrigation systems.
The low translocation characteristics of Nemacur would not make it suitable for
field application through a porous tube applicator. Vydate however, does offer
some definite possibilities for field application through a porous tube appli-
cator. Nematode populations are generally the highest in the surface or upper
soil region. A lethal Vydate concentration (according to its manufacturer) is
5 ppm. This minimal concentration in the Vydate test was attained as far out as
60 cm horizontally (from the applicator) at a 23 cm fP^-.^^h multiple later
als on a 120 cm spacing the overlap effect in the water dist"bution pattern
should provide a 5 ppm or greater Vydate concentration in a maDor portion of the
.131
-------
soil profile. The above "field application inference" is just that; an inference
based on laboratory tests. The affects upon the nematicide distribution patterns
of higher initial soil water contents and reduced initial concentrations must be
field evaluated before the inference label can be removed.
76:03F-051
SUBSURFACE AND FURROW IRRIGATION EVALUATION FOR BEAN PRODUCTION,
Sepaskhah, A.R., Sichani, S.A., and Bahrani, B.
Pahlavi University, College of Agriculture, Irrigation Department, Shiraz, Iran
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 1089-1092, Special Edition, 1976. 4 fig, 3 tab, 19 ref.
Descriptors: *Subsurface irrigation, *Furrow irrigation, Irrigation, Irrigation
practices, Beans, Crop production, Water conservation.
The water use efficiency, yields of beans and economic feasibility of furrow and
subsurface irrigation systems were compared in field experiments. Subsurface
irrigation required 55 percent less water to produce a yield of beans comparable
to that obtained with furrow irrigation. Water use efficiencies of 81.9 and
37.5 kg of beans per cm of water were obtained for the treatments irrigated with
subsurface and furrow irrigation systems, respectively. Spacing for subsurface
irrigation laterals was obtained from a laboratory experiment and was 84 percent
of the theoretical spacing. If the usable life of the porous pipe can be extended
to 3 years, the price of the subsurface system could be comparable to that of the
furrow irrigation system when water cost is $0.0135/cu m.
76:03F-052
EVAPOTRANSPIRATION AND WATER USE EFFICIENCY BY SOYBEAN LINES DIFFERING IN GROWTH
HABIT
Singh, B.P., and Whitson, E.N.
Fort Valley State College, Division of Agriculture, Fort Valley, Georgia.
Agronomy Journal, Vol. 68, No. 5, p 834-835, September-October 1976. 2 fig, 4 ref.
Descriptors: *Soybeans, Evapotranspiration, Crop response, Canopy, Eddies, Crop
production, Water vapor, Air circulation.
Determinate and indeterminate soybeans differ in canopy morphology due to a dif-
ference in their growth habits. Canopy morphology may affect receipt and loss of
radiation, air circulation, and eddy turbulence. These factors may in turn influ-
ence heat and water vapor transfer, thereby possibly influencing plant water use.
The objective of this study was to determine the effects of soybean growth habits
on evapotranspiration and water use efficiency. The daily evapotranspiration rate
for both lines was maximum at the early reproductive stage. Water extraction by
both lines extended to a 122-cm soil depth, the lowest depth measured. The total
evapotranspiration by the determinate line was 41.2 cm as compared to 39.2 cm for
the indeterminate line. The difference in growth habits amounted to only a small
fraction of the total evapotranspiration. The determinate line produced 24.9 per-
cent more grain than the indeterminate line by utilizing only 5.6 percent more
water. This accounted for an 18.1 percent greater water use efficiency of the
determinate line. These values suggest that growth habits affect water use effic-
iency primarily by controlling grain yield.
76.-03F-053
EVALUATION OF SLOW-RELEASE NITROGEN FERTILIZERS ON PENNPAR CREEPING BENTGRASS,.
Waddington, D.V., and Duich, J.M.
Pensylvania State University, Department of Agronomy, University, Park, Penn-
sylvania, 16802.
Agronomy Journal, Vol. 68, No. 5, p812-815, September-October 1976. 3 fig, 2 tab,
11 ref.
Descriptors: Fertilization, Nutrients, Turf grasses. Nitrogen, Urea, Crop pro-
duction, Turf, Kentucky Blue Grass.
132
-------
As new fertilizer materials become available for turfara
relative merits should be evaluated under various fiel
recommendations can be made concerning their"™ Intudonennpar
creeping bentgrass single applications of four slow-release N fertilizers and
multiple applications of urea applied to fine, mixed, mesic Typic Hapludalf soil
were compared for four consecutive growing seasons. Split applications of slow
release materials were also included in the fourth season? Clipping ylelL and"
turf color were used to evaluate response to fertilization. Growth^patterns
varied from year to year, but certain relationships between treatments generally
remained the same: 1) greatest initial response occurred with isobutylidene di-
urea; 2) yields from slow-release treatments equalled or exceeded those from the
urea treatment for 13 to 14 weeks, thereafter urea gave higher yields; 3) response
from sulfur-coated urea and resin-coated fertilizer was intermediate between and
ureaform. Split applications of slow-release sources reduced the flush of spring
growth and increased turf color in the fall when single spring applications were
used. The delay in response noted after isobutylidene diurea applications on
Kentucky bluegrass in other experiments was not as apparent under the conditions
of this study, possibly due to the incorporation of fertilizer by aerating and
topdressing at the time of application and more liberal watering on the bentgrass
area.
76:03F-054
RELATIONSHIP BETWEEN POTATO YIELD AND OXYGEN DIFFUSION RATE OF SUBSOIL,
Saini, G.R.
Agriculture Canada, Research Station, Fredericton, New Brunswick, Canada E3B 4Z7
Agronomy Journal, Vol. 68, No. 5, p 823-825, September-October 1976. 1 fig, 1 tab,
24 ref.
Descriptors: Potatoes, Crop response, Crop production, Soil physical properties,
Soil compaction, Organic matter, Soil properties, Soil moisture, Field capacity.
Numerous studies in the past have been made of the effects of soil compaction on
patato yield by deliberately packing the soil in small experimental plots. Since
information obtainable from such experiments has limited value in the economic
assessment of crop production of an area, a study was conducted on 10 different
farmer's fields to find out which soil physical property (or a combination of
properties) may best define the prevailing productive capacity of a soil for
potatoes. Various soil properties (stones, sand, silt, clay, bulk density, pene-
trometer readings, and organic matter) were measured according to the methods
given by Black (1965) at a depth of 20 to 28 cm (8 to 11 inches) where the com-
pact soles usually occur. Oxygen diffusion rate, however, was determined at a
moisture content of field capacity by the platinum microelectrode method (Lemon
and Erickson, 1952) using a rate meter manufactured by Jensen Instruments, Tacoma,
Washington. Stepwise multiple regression analysis of potato yields of cultivar
'Netted Gem' and the soil properties indicated that oxygen diffusion rate of sub-
soil was one single factor which highly correlated with marketable yield (r =
+0.82). The correlation coefficient was significant at the 1% level of probabil-
ity. Further addition of other properties did not improve the r value signifi-
cantly. The study indicates the oxygen diffusion rate of subsoil is useful
criteria to diagnose the prevailing physical condition of the soil which in turn,
could be related to the relative productive capacity of soil for potato production
in New Brunswick, Canada.
76:03F-055
STOMATAL RESPONSE TO LEAF WATER POTENTIAL AS AFFECTED BY PRECONDITIONING WATER
STRESS IN THE FIELD
Thomas, J.C., Brown, K.W., and Jordan, W.R. .
Texas A and M University, Department of Soil and Crop Sciences, College Station,
Tsx3S V 7 R 4 ^
Agronomy Journal, Vol. 68, No. 5, p 706-708, September-October 1976. 4 fig, 13
ref.
Descriptors: Grain sorghum, Cotton, Crop response, Moisture stress Stomata
Crop production. Irrigation, Irrigation Effects, Irrigation practices, Soil water.
Previous research has shown that stomatal response to decreasing soil water poten-
tial of chamber-grown sorghum'and cotton posure to previous water stress. This
133
-------
work was undertaken to determine if stomatal response of field-grown plants is
also altered by previous water stress. Stoneville 213 cotton was grown in the
field under movable rainshelters and was subjected to three treatments: control —
well watered, one period of water stress, and two periods of water stress. After
this preconditioning period, all plants underwent a final stress during which
stomatal response to leaf water potential was measured. The periods of precon-
ditioning water stress were characterized by decreased cumulative growth as meas-
ured by leaf area per plant. Leaf areas for the control, one soil water stress
plant, and two soil water stress plants were 5,200, 2,200, and 1,200 sq cm, respec-
tively. Lower stomates of preconditioned field-grown plants remained open to lower
leaf water potentials (-28 to -30 bars) during the final stress than those of
plants which were not preconditioned (-22 bars). These results were similar
to those found previously on chamber-grown plants which had been exposed to
more frequent but shorter stresses. The six to eight bar adjustment in leaf
water potential versus stomatal resistance as a result of previous water
stress indicates a need for caution in interpreting data from plants of unknown
water stress history.
76:03F-056
SULFUR AND NITROGEN REQUIREMENTS OF SUGARCANE,
Fox, R.L.
Hawaii University.- Department of Agronomy and Soil Science, Honolulu, Hawaii
Agronomy Journal, Vol. 68, No. 6, p 891-896, November-December 1976. 9 fig, 3 tab,
25 ref.
Descriptors: Sugarcane, Nitrogen, Sulfur, Nutrients, Fertilizers, Fertilization
The internal S requirement of sugarcane is not well defined and there are no pub-
lished data on the external S01-S requirements. The objectives of this study were
to provide data on sulfur distribution and N:S ratios in sugarcane. Sugarcane
was grown in solution cultures and in potted soil material which provided several
concentrations and ratios of N03 and SOI in solution. External S and N require-
ments were estimated from plots of yield vs. S04 or N03 concentrations in solution
cultures and in artificial soil solutions. The external S requirements at age 35
days was about 9 ppm. After 70 days the requirement was about 5 ppm when N was
adequately supplied. The external S requirement for early growth was 0.36% S in
the whole plant and 0.24% for leaf blades 3 through 6. When plants were 70 days
old, 0.10% S in leaf blades or 0.08% S in leaf sheaths was sufficient. Sulfur-
deficient, field-grown sugarcane 18 months old contained 0.075% S in leaves 3
through 6 and 0.072% S in the corresponding leaf sheaths. Sulfur fertilized sugar-
cane contained 0.138% and 0.232% for the same tissues. Ratios N:S differed for
various tissues of the same plant. Distribution of S in the plant may be a valu-
able tool for assessing the S status of sugarcane. When S is deficient, old leaf
blades contain more S than-corresponding leaf sheaths, and blades and sheaths of
leaves 3 to 6 contain about equal concentrations of S. Good S nutrition was
associated with an elevated concentration of S in leaf sheaths as compared with
leaf blades.
76:03F-057
NITRIFICATION INHIBITOR WITH FALL-APPLIED VS. SPLIT NITROGEN APPLICATIONS FOR
WINTER WHEAT,
Boswell, F.C., Nelson, L.R., and Bitzer, M.J.
Georgia University, Agricultural Experiment Station, Department of Agronomy,
Georgia Station, Experiment, Georgia 30212
Agronomy Journal, Vol. 68, No. 5, p 7370740, September-October 1976. 1 fig, 5 tab,
11 ref.
Descriptors: Nitrification, Nutrients, Fertilization, Nitrogen, Crop response,
Crop production, Wheat, Georgia, Soil analysis
Since numerous small grain producers desire to make fall application of efficient
levels of N for maximum yields, studies are needed to determine the efficiency of
fall-applied N (with and without an inhibitor) vs. split N applications. Field
studies were conducted at two locations each year over a 3-year period with the
objective of evaluating the response of wheat to N rates, time of application,
and effect of a nitrification inhibitor on soils of different characteristics.
134
-------
soil (->
,
topdressed in the spring, was superior toapplyingll tnelTifti^ra
inclusion of the nitrification inhibitor, 2-chloro-6- (trichloromethyl
(N-Serve), with ammonium sulfate in the fall at the rate of 84 ka/hl A, A
influence yields or N levels in the tissue or grain The LnibitS hfd nn ff
on elements other than N. Although the nitrification Inhibitor influenced the
retention of the NH4(-)N in the soil until the January sampling, this retention
7£%n?h T ?• ^ * * !0±i ^ thS MarCh samPlin9- Therefore, we concluded
S L5S L ?SX? if'3 ^ °f ^e complete fertilizer at the ra^e of 28 or even
84 kg/ha in the fall is inadequate for maximum wheat yield in either the coastal
plain or piedmont regions of Georgia. A nitrification inhibitor applied with the
ammonium sulfate was ineffective in preventing nitrification of the ammonium nitro-
gen or to increase yields.
76:03F-058
INFLUENCE OF NITROGEN, NARROW ROWS, AND PLANT POPULATION ON COTTON YIELD AND
GROWTH
Koli, S.E., and Morrill, L.G.
Crops Research Institute, Department of Agronomy, P.O. Box 3785, Kumasi, Ghana
Agronomy Journal, Vol. 68, No. 6, p 897-901, November-December 1976. 3 fig, 8 tab
18 ref.
Descriptors: Cotton, Crop response. Fertilization, Fertilizers, Nitrogen, Plant
population, Crop production
Narrow row planting of cotton has the potential for improving yield and production
efficiency. Fertilizer needs and other production technology for narrow row cot-
ton have received little attention, especially the nitrogen (N) requirement. The
objective of this study was to ascertain if N fertilizer, narrow row, and high
population, has any effect on growth and yield of dryland cotton. The relation-
ship between petiole NO(-)3(-)N at various stages of development and yields was
also investigated. Row spacing (25, 51, and 76-cm) , plant populations (123,550
and 173,000 plants/ha), and N rate (0, 45, and 90 kg/ha) variables were placed
in a factorial arrangement of a randomized, complete block design with four repli-
cations. Low N treatments (45 kg/ha) produced no significant change in yield,
but higher N rates reduced yield significantly. The 25 and 51-cm row spacings
produced significantly higher yield than 76-cm rows. The range of plant popula-
tions used did not materially affect yield, but there was a significantly N-popu-
lation interaction. Narrow rows reduced plant height. NO(-)3(-)N levels in pet-
ioles increased with increased N rate, being highest at the square stage of plant
growth and decreasing sharply at the flower and boll stages. There was no signif-
icant correlation between petiole NO(-)3(-)N and yield. Narrow row cotton can
result in higher yield and is especially of interest where the length of growing
season is not optimum.
76:03F-059
OPTIMUM CONTROL OF IRRIGATION WATER APPLICATION,
Fogel, M.M. , Duckstein, L. , and Kisiel, C.C.
Arizona University, Department of Watershed Management, Tucson, Arizona
Journal of Hydrology, Vol. 28, No. 2/4, p 343-358, February 1976. 4 fig, 17 ref.
OWRT B-032-ARIZ(26)
Descriptors: *Irrigation water, *Management, *Mathematical models, *Decision
making, Optimization, Farms, Soil water, Hydrologic aspects, Stochastic process,
Water costs. Methodology, Equations, Systems analysis, Forecasting.
Managing farm irrigation systems involves the choice of method, time, and quantity
of irrigation water application. This paper focuses on the problem of continuous
or periodic review of the factors that affect crop production (i.e. , climate),
that is, making decisions based on relatively short-term predictions. Finding
the optimal irrigation policy is examined using a new approach based on the idea
that an analogy exists between a business that stocks physical goods and a farm
irrigation syltem in which the soil is a reservoir that ^ores water for future
use fay the plant. The demand on this reservoir may be either J^™1"*" °*
stochastic. It is shown that inventory models can be adapted to the
involving the efficient operation of such farm irrigation systems.
135
-------
76:03F-060
APPLICATION OF A TWO-VARIABLE MITSCHERLICH FUNCTION IN THE ANALYSIS OF YIELD-WATER-
FERTILIZER RELATIONSHIPS FOR CORN
Hexem, R.W., Sposito, V.A., and Heady, E.O.
Iowa State University, Center for Agricultural and Rural Development, Ames, Iowa
50010
Water Resources Research, Vol. 12, No. 1, p 6-10, February 1976. 4 fig, 3 tab,
6 ref.
Descriptors: Model studies. Fertilizers, Fertilization, Corn, Colorado, Kansas,
Simulation analysis, Crop response, Nutrients, Crop production.
Variations of models developed by E.A. Mitscherlich in the early part of this
century are periodically used for estimating input-output relationships for plants.
Mitscherlich's work focused on a single variable. While these exponential models
incorporate features of theoretical appeal, the procedures for quantifying the
models are relatively complex when two or more independent variables are included.
In fits of Mitscherlich and polynomical forms to yield-water-fertilizer data for
corn grown under experimental conditions in Colorado and Kansas, test statistics
for the polynomial forms are as good as or better than those for the more complex
Mitscherlich models.
76:03F-061
COMPARISON OF MODIFIED MONTMORILLONITE TO SALTS AND CHELATES AS CARRIER FOR MICRO-
NUTRIENTS FOR PLANTS: II. SUPPLY OF IRON
Navrot, J. and Banin, A.
The Hebrew University, Department of Soil and Water Sciences, Rehovot, Israel
Agronomy Journal, Vol. 68, No. 2, p 358-361, March-April 1976. 2 fig, 5 tab, 7 ref.
Descriptors: Iron, Nutrients, Fertilizers, Fertilization, Copper, Zinc, Manganese,
Clays, Tomatoes, Beans, Crop response.
Symptoms of iron deficiency appear very frequently in the calcareous soils which
represent a major part of the agricultural soils of Israel; therefore a search
for novel carriers of iron is constantly conducted. Previous studies showed that
Cu, Zn, and Mn, attached to modified montmorillonite, can effectively replace salts
and chelates as carriers for micronutrient elements for plants. In this research,
the effect of iron attached to montmorillonite clay on element uptake and yield
of plants was compared to that of commonly used iron sulphate or EDTA and EDDHA
chelates. In the greenhouse, beans were grown in two calcareous, iron deficient
soils and were treated with either FeS049 Fe(+3)-EDTA, Fe(+3)-EDDHA, or Fe(+2)
bound to montmorillonite clay- The rates of iron added varied from 15 to 60 mg
Fe/kg soil for the salt and 3 to 12 mg Fe/kg soil for the chelates and the clay
forms. It was found that Fd(+2)-clay and Fe(+3) in chelates, added at equivalent
rates, supplied iron in comparable amounts; FeS049 added at the conventional rates
which are five to ten times higher than that added as clay- and chelate-bound iron,
caused similar or lower uptake and yields. Moreover, the slow release of iron
from Fe-clay, even when supplied in high rates, prevented excessive iron uptake
which otherwise, as in the case of the chelate FeEDDHA, interferred with
plant development. It is suggested that iron attached to montmorillonite
clay can be used as an efficient source of iron for plants grown in calcarous
soils.
76:03F-062
COMPARISON OF MODIFIED MONTMORILLONITE TO SALTS AND CHELATES AS CARRIER FOR
MICRONUTRIENTS FOR PLANTS: I. SUPPLY OF COPPER, ZINC, AND MANGANESE
Banin, A., and Navrot, J.
The Hebrew University, Department of Soil and Water Sciences, Rehovot, Israel
Agronomy Journal, Vol. 68, No. 2, p 353-358, March-April 1976. 4 fig, 7 tab,
16 ref.
Descriptors: Nutrients, Fertilizers, Fertilization, Copper, Zinc, Manganese,
Clays, Tomatoes, Beans, Crop response
The purpose of the study was to compare the effectiveness of a novel micronutrient
fertilizer, modified montmorillonite clay, to the conventionally used salts and
136
-------
chelates as carriers of micronutrients to plants. Three elements — Cu Zn and
Mn --in combination in various'rates, and in three forms? as sulphates! EDTA
chelates or attached to montmorillonite clay, where applied to two micronutrient
deficient sandy soils.. Tomato and beans were grown under controlled greenhouse
conditions in the treated soils. The application of micronutrient element? in
all of the forms used, significantly increased plant yields. In addition, the
supply of micronutrients significantly increased the elemental concentrations of
the plants. However the highest concentration of elements found in the plants
did not always correspond to the highest yields. Generally the lower levels of
addition of combined micronutrients improved the growth conditions considerably
and the higher ones were less effective. The clay carrier was similar to the
expensive chelates and generally more efficient than the salts in element supply
and this resulted in better yield responses. The optimal rate of application
of the combined elements for dry yield production in tomato plants in the
soils studied appeared to be: 0.5 me Cu, 1.6 mg Zn, and 2.5 mg Mn per kg
of soil for the clay and chelate forms and somewhat higher for the salts!
76:03F-063
LAND FORMING SYSTEMS TO IMPROVE WATER USE EFFICIENCY
Koelliker, J.K.
Kansas State University, Department of Agricultural Engineering, Manhattan, Kansas
Kansas Water Resources Research Institute, Manhattan, KWRRI Contribution No. 184,
70 p, November 1976. 14 fig, 11 tab, 44 ref, 3 append. OWRT A-068-KAN(2) , 14-31-
0001-5016.
Descriptors: *Land forming, *Terracing, *Soil moisture, *Kansas, *Water utiliza-
tion, Groundwater recharge, Rainfall, Recharge, Wheat, Grain sorghum, Fallowing,
Model studies, Demonstration watersheds, Crop production, Watershed management,
Monitoring, Agricultural watersheds. Potential water supply.
Two years of operation of conservation bench terraces and level pans at Garden
City, Kansas conclusive as to determining increased water use efficienty for crop
production. Precipitation in both years was well below normal and little surface
runoff occurred. Measurements of precipitation, watershed runoff and soil moisture
in the top 2.3 m were monitored and used to calibrate a soil moisture budget sim-
ulation model for western Kansas. The model was calibrated with one year's data
from a fallow watershed. Predicted total soil moisture content in the 2.1m soil
profile averaged within 2.4 percent of actual field values. The model was then
used to estimate the potential for ground water recharge from conservation bench
terraces over the period 1945-1974.
76:03F-064
NITROGEN NUTRITION AND YIELD OF SUGARCANE AS AFFECTED BY N-SERVE
Prasad, M.
M.J. Weeds and Associates, 13 Kilbarrack Grove, Dublin 5, Ireland
Agronomy Journal, Vol. 68, No. 2, 343-346, March-April 1976. 4 fig, 3 tab, 13 ref.
Descriptors: Sugarcane, Fertilizers, Fertilization, Nitrogen, Irrigation effects,
Irrigation practices, Nitrification, Nutrients.
Very few experiments have been conducted to evaluate N-Serve formulated with N-
fertilizer for sugarcane. N-Serve when formulated with N-fertilizer increased
sugarcane yields in the Philippines and in Louisiana but failed to do so in
Puerto Rico and in Mauritius. In view of the relatively few experiments conducted
with N-Serve for sugarcane and the conflicting nature of the results, a pot exper
iment in drums and a field experiment were conducted to study the effect of N-
Serve formulated with solid ammonium sulfate (AS) on sugarcane ( HJ 5741 ) yield,
leaf N content, tillering, and on soil N. In the pot experiment two soils, a
clayey loam and a loamy sand were used combined with a high and low irrigation
treatment. There were two rates of AS with and without N-Serve. A control
treatment was also included. N-Serve was applied at 2.5% of the weight of AS.
In the field experiment on a sandy clay there were three rates of AS with and
without N-Serve. A control treatment was also included. N-Serve was applied
at a flat rate of 24 liter/ha.
137
-------
76:03F-065
NON-UNIFORM INFILTRATION UNDER POTATO CANOPIES CAUSED BY INTERCEPTION, STEMFLOW,
AND HILLING,
Saffigna, P.G., Tanner, C.B., and Keeney, D.R.
Wisconsin University, Department of Soil Science, Madison, Wisconsin 53706
Agronomy Journal, Vol. 68, No. 2, p 337-342, March-April 1976. 4 fig, 2 tab,
38 ref.
Descriptors: Sprinkler irrigation, Irrigation practices, Irrigation effects,
Infiltration, Potatoes, Leaching, Soil water, Deep percolation, Model studies.
It is generally assumed that infiltration of sprinkler irrigation and rainfall
under potato is uniform. However we observed non-uniform infiltration beneath
the hills of sprinkler-irrigated potatoes grown on Plainfield loamy sand (Typic
Udipsamment; sandy, mixed, mesic). The objective of this field study was to
determine the effects of foliage interception and hilling on non-uniform infil-
tration, since concentrating water in local zones would increase deep drainage
and nitrogen leaching. To do this we traced the rainfall and irrigation infil-
tration pattern with Rhodamine WT dye and collected the stemflow in stem collars.
Throughfall of rainfall, the soil water content, and soil water tension also were
measured. From 20 to 46% of the irrigation and from 4 to 23% of the rainfall on
the canopy flowed down the stems. Stemflow increased the soil water content
around the stems and moved Rhodamine dye deep beneath the soil surface. Deep
movement of dye beneath the furrows was caused by runoff from the hills and by
leaf drip from the outer foliage. The results obtained suggest that irrigation
and fertilizer management could be improved by taking this non-uniform infiltra-
tion pattern into account. Smaller irrigations should improve water use effic-
iency and minimize nitrate leaching. Further, evaluation of solute movement
by soil sampling should consider the spatial variation introduced by the non-
uniform infiltration. Finally, predictive leaching models should account for
non-uniform infiltration.
76:03F-066
EFFECT OF INCREASING FOLIAGE AND SOIL REFLECTIVITY ON THE YIELD AND WATER USE
EFFICIENCY OF GRAIN SORGHUM,
Stanhill, G., Moreshet, S., and Fuchs, M.
The Volcani Center, Division of Agricultural Meteorology, Bet Dagan, Israel
Agronomy Journal, Vol. 68, No. 2, p 329-332, March-April 1976. 1 fig, 3 tab,
5 ref.
Descriptors: Grain sorghum, Crop production. Crop response, Water use efficiency.
The effect of increasing foliage and soil reflectivity on yield and water use
efficiency of grain sorghum crops grown under arid conditions with stored soil
water only, was studied during 3 years of randomized block field experiments.
Suspensions of kaolin were sprayed on the soil and/or foliage at different growth
stages to select the most effective placement and timing for the treatment. Soil-
only applications were ineffective in increasing yields but canopy sprays resulted
in an additional yield of 446 kg/ha, or 11% over the unsprayed controls, averaged
over the 3 years of experimentation. The most effective period for foliage sprays
started seven weeks after seedling emergence and ended 10 days later, immediately
before the panicles emerged. During this period, known to be critical for sorghum
grain yield response to water status, the yield response averaged 2 kg grain/1 kg
kaolin applied. Neither the total seasonal water use nor the rate of soil water
depletion was affected by the foliage reflectance treatment. It is concluded
that under arid conditions, kaolin suspensions sprayed twice on the foliage of
unirrigated grain sorghum crops during the prepanicle-emergency stage shows
promise as an effective method of increasing grain yield.
76:03F-067
GROWTH AND MINERAL COMPOSITION OF RICE AT VARIOUS SOIL MOISTURE TENSIONS AND
OXYGEN LEVELS,
Patrick, W.H. Jr., and Fontenot, W.J.
Louisiana State University, Louisiana Agricultural Experiment Station, Department
of Agronomy, Baton Rouge, Louisiana 70803.
138
-------
Agronomy Journal, Vol. 68, No. 2, p 325-329, March-April 1976. 8 fig, 16 ref.
r"'POMe' ^"*°i-ure, Soil water,
T^ bf*e£ f °^h °f/iCe in a "°°aea soil as compared to an upland soil has been
attributed to the reducing conditions caused by submergence. No study has been
carried out, however, in whieh the effects of the soil moisture status has been
separated from the effect of the oxidation-reduction conditions on early growth
and mineral composition of lowland rice was determined by growing plants in
artificially packed soil columns maintained under different soil moisture tension
and oxygen conditions. Since soil aeration is largely governed by the moisture
status of the soil, this study was designed to separate these effects by subject-
ing the rice plant to different aeration conditions while at the same time attempt-
ing not to limit moisture supply. In one experiment different redox conditions
were established by maintaining soil columns at soil moisture tensions ranging
from 0 to 80 cm during growth of the plants. In a second experiment plants were
grown at soil oxygen levels of 0, 3, 8, and 12% while soil moisture was maintained
at 10 cm moisture tension. Vegetative growth of rice was greater under reduced
conditions than under oxidized conditions in both experiments. The P concentra-
tion of the plant was much higher under reduced conditions than under oxidized
conditions. Reduced conditions increased the solubility of P, Fe, and Mn in the
soil although no consistent effect of reducing conditions on plant uptake of Fe
and Mn was observed.
76:03F-068
WATER TRANSPORT IN WHEAT PLANTS IN THE FIELD,
Denmead, O.T., and Millar, B.D.
Commonwealth Scientific and Industrial Research Organization Division of Environ-
mental Mechanics, P.O. Box 821, Canberra City, Australian Capital Territory,
Australia
Agronomy Journal, Vol. 68, No. 2, p 297-303, March-April 1976. 5 fig, 5 tab, 27
ref.
Descriptors: Wheat, Transpiration, Evapotranspiration, Water vapor,- Model studies.
Most previous studies of water transport in crops have been based on simplified
models of plant anatomy and canopy transpiration. Usually changes in the water
potential of a, particular leaf have been related to the water loss from the whole
canopy. We present a more detailed analysis of plant water transport which accounts
for the spatial distribution of water flows and transpiration losses throughout
the canopy, and use it to estimate flow resistances in different segments of the
pathway. Micrometeorological measurements of the flux densities of water vapor
in the canopy were used to infer water fluxes through roots, stem sections, leaves,
and ears of wheat plants in the field. Simultaneous measurements of soil and
leaf-water potentials permitted calculation of flow resistances in roots, stems,
and leaves. The study shows clearly how the water loss from one part of the
canopy influences the development of water potentials in other parts and points
up the difficulties of simplified transport models.
76:03F-069
NUTRIENT UPTAKE BY CORN AND GRAIN SORGHUM SILAGE AS AFFECTED BY SOIL TYPE, PLANT-
ING DATE, AND MOISTURE REGIME,
Fribourg, H.A. , Bryan, W.E., Lessman, G.M., and Manning, D.M.
Tennessee University, Department of Plant and Soil Science, Knoxville, Tennessee
Agronomy Journal, Vol. 68, No. 2, p 260-263, March-April 1976. 4 tab, 6 ref.
Descriptors: Corn, Grain sorghum, Soil moisture, Soil water, Tennessee, Nutrients,
Nitrogen, Phosphorus, Potassium, Calcium, Manganese, Fertilizers.
Few data have been published on whole-plant nutrient removal by silage crops as
influenced by soil types and species. In order to quant ^ ^tx^ rera °\f ***.
corn and grain sorghuS silage crops, early (30 April-15 May) and late (2-12 June)
plantings of 'Funk G-4831' corn and 'AKS 614' sorghum were grown in 1969 in 34
environments on 12 soil types, two soils at each of six locations in Tennessee.
139
-------
Non-irrigated plots of the two plantings were grown on all soils, and irrigated
plots were added to five of the soils. The corn was harvested for silage when 80
to 90% of the kernels were dented, and grain sorghum when the oldest seeds were
in the soft dough stage. Tissue samples were collected and analyzed for N, P,
K, Ca, and Mg. Total seasonal uptake was calculated by multiplying percent com-
position of each element by dry matter yield/ha. Corn silage yields ranged from
about 6 to 28 metric tons/ha, and sorghum silage yields ranged from about 7 to
18 metric tons/ha. Nutrient uptake generally increased linearly with yield.
Mean total uptake of N, P, K, Ca, and Mg were, for corn silage, 192, 28, 144, 39,
and 37 kg/ha; and, for grain sorghum silage, 169, 26, 143, 40, and 35 kg/ha,
respectively-
76:03F-070
ESTIMATING EVAPORATION AND TRANSPIRATION FROM A ROW CROP DURING INCOMPLETE COVER,
Tanner, C.B. and Jury, W.A.
California University, Department of Soil Science and Agricultural Engineering,
Riverside, California
Agronomy Journal, Vol. 68, No. 2, p 239-243, March-April 1976. 2 fig, 2 tab,
25 ref.
Descriptors: Model studies, Evapotranspiration, Evaporation, Transpiration,
Potatoes, Lysimeters, Crop response. Crop production.
In order to model the evapotranspiration (ET) from a crop with incomplete cover,
the evaporation (E) is estimated separately from the transpiration (T) since E
and T usually do not vary proportionately- Our objective was to develop and test
an ET model based on the 'potential1 E and T estimates that are consistent with
the potential ET estimate. When E is less than the potential E (the falling rate
phase), it is estimated by two approaches based on E falling as the square root
of T; however, the model assumes transpiration is at the 'potential' rate. ET
estimates during cover development of potato for 2 years were compared with lysim-
eter measurements. The standard error of estimate varied from 0.40 to 0.94 mm/day
depending on the method for estimating E. The estimate of cumulative ET for 4
weeks varied from the lysimeter a maximum of 1 cm in 9.7 cm ET.
76:03F-071
YIELDS AND SUGAR CONTENT OF SUGARBEETS AS AFFECTED BY DEFICIT HIGH-FREQUENCY
IRRIGATION,
Miller, D.E., and Aarstad, J.S.
United States Department of Agriculture, Department of Soil Science, Prosser,
Washington 99350
Agronomy Journal, Vol. 68, No. 2, p 231-234, March-April 1976. 2 fig, 5 tab,
7 ref.
Descriptors: Sprinkler irrigation, Sugar beets, Crop response, Crop production,
Evapotranspiration, Irrigation effects, Irrigation practices. Irrigation engin-
eering, Irrigation systems.
Installation and operating costs of irrigation systems are related to system capac-
ity and amount of water applied. If sprinkler systems can be designed for less
than usual peak evapotranspiration rates, initial costs will be less. If less
water is applied, operating expenses will decrease. Previous work indicated
that sugarbeets can be grown satisfactorily under high-frequency deficit irriga-
tion (daily or more often at rates less than evapotranspiration) with soil water
supplying part of the irrigation deficit. A field study was conducted, using
solid-set sprinklers, with the objective of determining the minimum amount of
irrigation water that must be applied during peak use periods to avoid reduction
in sugar yields. Treatments involved irrigation each morning at rates equivalent
to various proportions of evaporation the previous day from a Class A Weather
Bureau pan. The soil indicates that with soils with adequate available waterhold-
ing capacity and crops that will tolerate deficit high-frequency irrigation,
systems can be designed for less capacity and total water application may be'
reduced. Soil water will be used to reduce the irrigation deficit.
140
-------
76:03F-072
SALINITY EFFECTS ON NITROGEN USE BY WHEAT CULTIVAR SONORA
Jadav, K.L., Wallinhan, E.F., Sharpless, R.G., and Printy' w L
Soil Testing Laboratories, Gujarat State, Junagadh, India ' '
Agronomy Journal, Vol. 68, No. 2, p 222-226, March-April 1976. 3 fig, 4 tab,
Descriptors: Nitrogen, Fertilizers, Fertilization, Nutrients, wheat, Salinitv
Saline soil, Crop production, Crop response. " '
The importance of N nutrition to fulfilling the high production potential of some
semidwarf wheat cultivars under irrigation culture raises problems of balance
between N and salinity. Inasmuch as growth may be limited in salt affected soils
thereby reducing total N requirement, the usual rates of fertilizer application '
may be excessive and thus contribute to the salinity problem. This study with
"Sonora 64' wheat was done to measure the effects of salinity and stand density
on plant growth and grain yield, to estimate N uptake in relation to salinity and
the stage of plant development, and to evaluate leaf-N as a basis for diagnosing
the N status of the plant.
76:03F-073
LONG-TERM RESIDUAL FERTILITY AND CURRENT N-P-K APPLICATION EFFECTS ON SOYBEANS,
Boswell, F.C., and Anderson, O.E.
Georgia University, College of Agricultural Experiment Stations, Georgia Station,
Experiment, Georgia 30212
Agronomy Journal, Vol. 68, No. 2, p 315-318, March-April 1976. 2 fig, 6 tab,
19 ref.
Descriptors: Soybeans, Fertilizers, Fertilization, Nitrogen, Phosphorus, Potas-
sium, Legumes, Crop response, Crop production.
Soybean yield response to currently applied fertilizers, especially N, has been
erratic while responses to residual P and K have been more consistent. This study
was conducted to determine if residual N-P-K fertilizers applied over a period
of years to other non-leguminous crops would influence soybean fertilizer require-
ments. Soybeans were planted on a Rarden si soil where plots has received the
same rates of P and K for 13 years. Previous N levels were 56 or 112 kg/ha,
depending on the crop. Since legumes had not grown on the area for at least 16
years, significant responses to 56 kg/ha of N occurred each year at the high level
of P and K. A greater yield response occurred from the P application than from K.
The fertilizer times year interaction effects on yield was greatest for P as
compared to N or K interactions when fitted to a regression model equation. The
highest rates of N-P-K resulted in significantly larger soybean seed, better qual-
ity (seed index), and higher crude protein content than low N-P-K rates or control
plots. Crude protein was inversely related to total oil content. Even though
relatively high levels of P and K were applied to certain plots for 16 years and
crop residues remained on the soil surface each year, high levels of extractable
(double acid) P or K were not found in the soil.
76:03f-074
RELATIONSHIP BETWEEN NITROGEN ANALYSIS OF SOYBEAN TISSUES AND SOYBEAN YIELDS,
Pal, U.R. and Saxena, M.C.
Kentucky University, Department of Agronomy, Lexington, Kentucky 40506
Agronomy Journal, Vol. 68, No. 6, p 927-932, -November, December 1976. 4 fig,
2 tab, 12 ref.
Descriptors: Nitrogen, Nutrients, Soybeans, Crop response, Fertilization.
In order to determine the applicability of N analysis of plant tissues as a diag-
nostic tool for N nutrition, it is essential to study the N status of soybean
plants under varying N supply. Field experiments were conducted to determine the
effect of N fertilization at the rates of 0, 25, 50, 100, and 200 and 300 dif-
ferent plant parts of nodulating (inoculated and uninoculated) and non-nodulating
isolines of 'Clark1 and 'Harosoy' soybeans at various stages of growth and to
correlate the N status of soybean plants with yields.
141
-------
76:03F-075
LEAF CONDUCTANCE RESPONSE TO HUMIDITY AND WATER TRANSPORT IN PLANTS,
Hall, A.E. and Hoffman, G.J.
California University, Department of Plant Sciences, Riverside, California 92502
Agronomy Journal, Vol. 68, No. 6, p 876-881, November-December 1976. 6 fig, 23
ref.
Descriptors: Stomata, Humidity, Leaves, Photosynthesis, Transpiration, Vapor
pressure.
Stomatal response to humidity is a potentially important adaptive characteristic.
The possibility that stomata may respond to humidity independently of changes in
bulk leaf water status was tested. Also the basis for reported differences in
leaf water potential response to transpiration was investigated. Simultaneous
measurements of in situ leaf water potential, transpiration, and net photosynthesis
were made in controlled environments using sunflower and pinto bean. Responses
of leaf conductance and leaf water potential to changes in ambient humidity and
root medium water potential were determined.
76:03F-076
EFFECT OF SOIL MOISTURE TENSION AND AMENDMENTS ON YIELDS AND ON HERBAGE N, P,
AND S CONCENTRATIONS OF ALFALFA,
Canada Department of Agriculture, Research Station, Melfort, Saskatchewan, Canada
SOE 1AO
Agronomy Journal, Vol. 68, No. 5, p 741-744, September-October 1976. 5 tab, 9 ref.
Descriptors: Alfalfa, Soil types, Nutrients, Soil moisture. Soil water. Soil
texture, Crop response, Nitrogen, Phosphorus, Sulfur, Barley, Farm wastes.
Low protein concentration has been observed in alfalfa herbage grown in Gray Wooded
Luvisol soils, particularly in cool, wet years. Nutrient deficiencies of N, P,
and S also occur on these soils. The objectives of this experiment were to deter-
mine how soil moisture and soil type interact with amendments to increase yield
and change N, P, and S concentrations in alfalfa herbage grown in the greenhouse.
Three Gray Wooded Luvisols, Typic Cryoboralf (Arborfield clay, Garrick clay loam,
Mollic Cryoboralf, and Waitville loam) and one Dark Gray Luvisol soil (Nipawin
sandy clay loam) times two soil moisture tensions (100 and 151 millibars) were
main treatments. Amendments of cattle manure, sedge peat, and wheat straw were
applied on subplots at 2.5% of soil weight. Additional subplots of a control and
ammonium nitrate were added. Yield of alfalfa was significantly related to mois-
ture use. Moisture use by alfalfa was higher with cattle manure incorporated in
the heavier textured Garrick clay loam and Arborfield clay soils than for other
amendments or soil types. The manure treatment applied to Garrick clay loam and
Arborfield clay soils under low soil moisture tension produced the highest herbage
yields.
76:03F-077
YIELD AND NITROGEN UTILIZATION BY RICE AS AFFECTED BY METHOD AND TIME OF APPLI-
CATION OF LABELLED NITROGEN,
Reddy, K.R. and Patrick, W.H. Jr.
Louisiana State University.- Louisiana Agricultural Experiment Station, Department
of Agronomy, Baton Rouge, Louisiana 70803
Agronomy Journal, Vol. 68, p 965-969, November-December 1976. 1 fig, 6 tab, 20
ref.
Descriptors: Nitrogen, Fertilization, Nutrients, Fertilizers, Rice, Crop response.
Recent increases in the cost of N fertilizer make it important to examine methods
or improving the utilization of fertilizer N by lowland rice. The objective of
the present investigations was to compare the effects of different methods and
times of N application on yield and utilization of N by lowland rice. Field
experiments using labelled fertilizer N were carried out during 1974 and 1975
utilizing different times and methods of application of ammonium sulfate on small
field plots. Fertilizer N was applied either by deep placement at the beginning
of the season or at one or more times during the growing season as surface appli-
cation. Relative contributions of native soil N and fertilizer N sources to plant
142
-------
uptake were followed during the growing season, and total uptake of native soil
N and fertilizer N by rice was determined at harvest. native soil
76:03F-078
SCHS™NG CENTER PIV°T SPRINKLER IRRIGATION SYSTEMS FOR CORN PRODUCTION IN EASTERN
COLORADO r
Heermann, D.F., Raise, H.R., and Mickelson, R.H.
Agricultural Research Service, United States Department of Agriculture, Department
of Agricultural Engineering, Fort Collins, Colorado 80521
Transactions of the American Society of Agricultural Engineers, Soil and Water
p 284-287, Special Edition 1976. 6 fig, 1 tab, 2 ref. water,
Descriptors: Scheduling, Irrigation systems. Sprinkler irrigation, Irrigation,
Corn, Colorado, Soil moisture, Crop production.
The United States Department of Agriculture Irrigation Scheduling Program was modi-
fied to probide multiple irrigation forecast dates for use with center pivot sprink-
ler irrigation systems. Four Eastern Colorado cooperators used the program and
developed confidence in the computer output mailed to them weekly. Each cooperator
used the information slightly differently. Some cooperators started the irrigation
system at the earliest recommended date, whereas others started their systems
between the 'start' and 'no later than' date. The two dates provided (a) the
'start' date when the soil water depletion was equal to the irrigation depth, and
(b) the 'no later than' date when the system must be started so as not to deplete
50 percent of the available soil water at any location in the field. The cooper-
ator who participated for 3 years reported that his yields had definitely increases
due to the scheduling program. Thus, the scheduling program certainly can be
beneficial to center pivot irrigation by increasing yields and conserving energy,
water and fertilizer (in the deep percolation).
76:03F-079
SOIL WATER DEPLETION—YIELD RELATIONSHIPS OF IRRIGATED SORGHUM, WHEAT, AND SOYBEANS
Musick, J.T., New, L.L., and Dusek, D.A.
United States Department of Agriculture, Southwestern Great Plains Research Center,
Department of Agricultural Engineering, Bushland, Texas
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 489-493, Special Edition 1976. 4 fig, 11 ref.
Descriptors: Soil water, Soil moisture. Irrigation, Irrigation effects, Grain
sorghum, Wheat, Soybeans, Irrigation practices.
Approximately 4 billion cu m of groundwater is pumped annually to irrigate sorghum.
wheat and soybeans grown in the fine-textured soils of the Southern High Plains.
Declining groundwater storage and the high costs of pumping necessitate that water
be applied only when it is needed to prevent appreciable yield reductions. Rela-
tionships between soil water depletion and grain yields provide a rational basis
for scheduling irrigations based on soil water in the major root zone.
76:03F-080
COMPARISON OF SIMULATED AND MEASURED NITROGEN ACCUMULATION IN BURLEY TOBACCO,
Zartman, R.E., Phillips, R.E., and Leggett, J.E.
Texas Technical University, Department of Agronomy, Lubbock, Texas 79409
Agronomy Journal, Vol. 68, No. 2, p 406-410, March-April 1976- 4 tab, 13 ref.
Descriptors: Fertilizers, Fertilization, Nitrogen, Tobacco, Nutrients, Simulation
analysis, Model studies, Root development.
Efficient utilization of N fertilizers by plants is important for scientific, eco-
nomic, and environmental reasons. The objectives of this experiment were 1
to experimentally evaluate the simultaneous mass flow and diffusion of N03(-)N to
tobacco roots and (2) to compare the calculated accumulation of N in tobacco, the
root of which was assumed to be a perfect sink for N03(-)N (Model I), or flux of
N03(-)N into the root which was assumed to be proportional to concentration of
N03(-)N at the root surface (Model II), to measured accumulation of N in Burley
143
-------
toi acco grown under field conditions. Model I overestimated accumulation of N an
average of 52%. Model II underestimated accumulation an average of 26%. The pro-
portionality constant, k, assumed by Model II, was found to be 4.27 times 10,to the
minus 7th power sq cm sec-1 throughout the growing season, except when moderate
plant water stress was experienced by the plant. The data show that the accumula-
tion of N by Hurley tobacco was proportional to the concentration of N03(-)N in
the soil solution.
76-.03F-081
SPRINKLER APPLICATION OF P AND ZN FERTILIZERS,
Hergert, G.W. and Reuss, J.O.
I-iebraska University - North Platte Station, Department of Agronomy, North Platte,
Nebraska
Agronomy Journal, Vol. 68, No. 1, p 5-8, January-February 1976. 2 fig, 7 tab,
9 ref.
Descriptors: Phosphorus, Zinc, Fertilizers, Fertilization, Nutrients, Sprinkler
irrigation, Irrigation practices, Irrigation water, Corn.
The rapid development of sprinkler irrigation in the Great Plains has stimulated
interest in applying fertilizers in sprinkler irrigation water. Sprinkler appli-
cation and conventional preplant application effects of P and Zn fertilizers on
the dry matter yield, nutrient content, and grain yield of corn were compared in
1968 and 1969. Both years preplant P treatments produced a significantly higher
dry matter yield during the first 5 weeks of the growing season. No significant
difference existed between P treatments after this time. In 1969 plants which
received preplant P and Zn contained slightly higher concentrations of P and Zn
than the plants which received sprinkler P and Zn. Grain yields were significantly
increased by Zn application in 1968 but not in 1969. In 1968 on a Nunn clay loam
soil the sprinkler-applied P did not move below a 4-5 cm depth. On a Haxtun loamy
sand in 1969 sprinkler-applied P moved to a depth of approximately 18 cm. Sprink-
ler-applied Zn moved to a maximum depth of 5 cm on both soils.
76:03F-082
CORN GROWTH AS AFFECTED BY AMMONIUM VS. NITRATE ABSORBED FROM SOIL,
Dibb, D.W. and Welch, L.F.
Potash Institute, Department of Agronomy, 91 Pecos Avenue, Route 1, Columbia,
Missouri 65201
Agronomy Journal, Vol. 68, No. 1, p 89-93, January-February 1976. 1 fig, 8 tab,
14 ref.
Descriptors: Ammonium, Nitrate, Corn, Crop response. Leaching, Denitrification,
Greenhouse experiments, Absorption.
The effect of NH4 on corn growth in a soil medium is of interest because of the
possibility of significantly decreasing leaching and denitrification losses of
applied N by preserving N in the NH4 form. The objective of this investigation
was to determine growth and nutrient content of corn plants when the principal
form of N was either NH4 or N03. Corn, grown in the greenhouse in a soil medium,
was allowed to absorb N as either NH4 or NO3. A chemical nitrification inhibitor
and different sources of added N were used to manipulate the form of N available
for absorption. The maximum amount of N absorbed as NO3 was estimated as the
difference between the N03 content of fallow and cropped pots at harvest. Plants
estimated to have absorbed at least 95% of their N as NH4.
76:03F-083
SUGARBEET YIELD AND QUALITY AS AFFECTED BY NITROGEN LEVEL,
Carter, J.N., Westermann, D.T., and Jensen, M.E.
Snake River Conservation Research Center, Department of Soil Science, Kimberly,
Idaho 83341
Agronomy Journal, Vol. 68, No. 1, p 49-55, January-February 1976. 5 fig, 4 tab,
15 ref.
144
-------
****' Nltr°gen' Nut™ts, Fertilizers, Fertilization, Crop
nN K climatic and s°il conditions, to determine
the effect of N level on sugarbeet yield and quality and to further develop and
refine both soil and tissue test methods for predicting N fertilizer needs for
efficient refined sucrose production. Previous studies indicate that N fertilizer
needs for maximum sucrose production may be predicted by considering yield poten-
tial and all N sources. Sugarbeets were grown under field conditions at N fertil-
izer levels varying from - to 448 kg n/ha on six sites throughout southern Idaho
to determine root yield, sucrose percentages, sucrose yield, impurity index and
, , ury nex an
plant N uptake in relation to the residual N03(-)N, mineralizable N, fertilizer N
and petiole N03(-)N. These experiments demonstrated that the N fertilizer needs
of sugarbeets can be determined by relating the root yield potential to the measur
residual N03(-)N plus a measured or estimated mineralizable N level for an area.
Optimum N level from all available soil and fertilizer sources has been found to
vary between 5 to 6 kg/metric ton of beet roots produced.
76:03F-084
IRRIGATION SCHEDULES FOR SUGARBEETS ON MEDIUM AND COARSE TEXTURED SOILS IN THE
NORTHERN GREAT PLAINS,
Cassel, O.K. and Bauer, A.
North Carolina State University, Department of Soil Science, North Carolina
Agronomy Journal, Vol. 68, No. 1, p 45-48, January-February 1976. 1 fig, 3 tab,
5 ref.
Descriptors: Sugar beets, Soils, Soil investigations, Soil water, Soil moisture,
Irrigation, Irrigation water, Tensiometers, North Dakota.
An increase in the access to irrigation water in the Northern Great Plains is
effecting large increases in the acreages of soils being irrigated. Much of this
water is being applied to medium to coarse-textured soils which hold a maximum
of 7 to 12 cm of available water in a 152 cm deep profile. An investigation was
conducted in the field to devise a system, using tensiometers, to schedule the
application of irrigation water to sugarbeets growing on these soils. Tensiometers
were installed at various soil depths, and irrigation water was applied with a
small plot irrigator when soil moisture tension reached a predetermined level.
One tensiometer located at the 45 cm depth was equally effective in scheduling
as two tensiometers, one positioned at a depth of 30 and one at 61 cm. Maximum
crude sugar yields of 8.4 to 8.8 metric tons/ha were obtained in 1971 and 1973,
respectively. Total water use efficiency was 0.15 to 0.16 metric tons of crude
sugar/ha per cm. The maximum irrigation water use efficiencies were 0.32 and 0.36
for 1971 and 1973, respectively. It is concluded that 56 to 62 cm of water,
well distributed throughout the growing season, is sufficient for sugarbeet pro-
duction in southeastern North Dakota in a year of normal growing season temper-
atures.
76:03F-085
NITROGEN RELEASE FROM ISOBUTYLIDENE DIUREA: SOIL pH AND FERTILIZER PARTICLE SIZE
EFFECTS,
Hughs, T.D.
Illinois University, Department of Horticulture, Urbana, Illinois 61801
Agronomy Journal, Vol. 68, No. 1, p 103-106, January-February 1976. 6 fig, 6 ref.
Descriptors: Nitrogen, Nutrients, Fertilizers, Fertilization, Soil moisture,
Soil properties, Soil investigations, Urea, Nitrification.
Soil-isobutylidene diurea (IBDU) mixtures were incubated to determine the effects
of soil pH and IBDU particle size on N release patterns. Such information is
needed for predicting rates and frequencies of application. All incubations were
conducted at a temperature of 21 ± 0.5 C and 28 ± 2% soil moisture Evidence was
obtained for excluding nura-N concentrations from Calculations of N recovery,
thus all recoveries were based on concentrations of(NH(+)4 + NO(-)3)(-)N. Nitro
gen release patterns from 0.7 to 0.8 mm IBDU particles in soil at initial pHs
of 5.7, 6.8, and 7.7 were determined. After four weeks of incubation, the amount
145
-------
of N released was equivalent to one-third of the IBDU-N for soil at pH 5.7, how-
ever, lesser amounts were released in soil at pH's 6.8 and 7.7. Differences in
N release were due to differences in NH(+)4(-)N concentrations, whereas concen-
trations of NO(-)3(-)N were not related to soil pH throughout the 10-week incu-
bation period.
76:03F-086
NUTRIENT UPTAKE BY RUSSET BURBANK POTATOES AS INFLUENCED BY FERTILIZATION,
Jackson, T.L. and Carter, G.E.
Oregon State University, Department of Soil Science, Oregon Agricultural Experi-
ment Station, Corvallis, Oregon 97331
Agronomy Journal, Vol. 68, No. 1, p 9-12, January-February 1976. 5 tab, 11 ref.
Descriptors: Nutrients, Fertilizers, Fertilization, Potatoes, Zinc, Manganese,
Oregon.
Zinc and Mn deficiencies have been observed frequently in potatoes grown on
eastern Oregon soils developed under arid conditions. The study was designed to
evaluate effects of band and broadcast applications of ammonium sulfate (AS) and
monocalcium phosphate (MCP) on yield and uptake of P, Zn, and Mn by Russet Burbank
potatoes grown on calcareous mineral soil deficient in N, P, Zn, and Mn. Potatoes
were grown under field conditions, harvested and evluated. Fertilizer treatments
were broadcast before planting and rototilled or banded at planting. Petiole
samples to identify nutrient concentrations were taken when tubers were 2 cm in
diameter. Whole plants were harvested 3 weeks later to measure nutrient uptake.
Petiole concentrations and plant uptake of both Zn and Mn were greater when AS
was banded than when broadcast, with or without band applications of Zn and Mn.
76:03F-087
RESPONSES OF THREE PEANUT CULTIVARS TO GYPSUM,
Walker, M.E., Keisling, T.C., and Dresler, J.S.
Coastal Plain Experiment Station, Department of Agronomy, Tifton, Georgia.
Agronomy Journal, Vol. 68, No. 3, p 527-528, May-June 1976. 2 tab, 12 ref.
Descriptors: Calcium, Gypsum, Crop response, Soil investigations, Nitrogen.
The differential response of peanut cultivars to soil applications of Ca has been
established for many years. Recent research reports, however, have indicated that
peanut cultivars respond similarly to Ca application. This may result in part
from new peanut cultivars differing in their response to Ca. Experiments were
therefore conducted on a low Ca soil to measure responses of three commonly grown
peanut cultivars to soil-applied Ca. Results from this experiment show that gyp-
sum had no effect on yield or sound mature kernels of Florunner peanuts. Florun-
ner peanuts produced higher yields and grades than Florigiant or NC-Fla 14,
regardless of treatments. Gypsum application to Florigiant and NC-Fla 14 peanuts
increased yields, sound mature kernels, and extra large kernels. In general,
gypsum increased the % oil in all cultivars. Florigiant contained less oil than
the other cultivars. Nitrogen content of the seed of all cultivars was reduced
by gypsum application. These data indicate that on low Ca soils Florunner peanuts
can produce higher yields and quality with or without gypsum, while Florigiant
and NC-Fla 14 need gypsum fertilization to increase yield and improve quality.
76:03F-088
NITROGEN AVAILABILITY TO WHEAT AS AFFECTED BY DEPTH OF NITROGEN PLACEMENT,
Daigger, L.A. and Sander, D.H.
Nebraska University, Department of Agronomy, Panhandle Station, Scottsbluff,
Nebraska
Agronomy Journal, Vol. 68, No. 3, p 524-526, May-June 1976. 4 fig, 10 ref.
Discriptors: Nitrogen, Wheat, Fertilization, Fertilizers, Crop production,
Nebraska, Soil moisture.
14fi
-------
The availability of residual N in the root zone greatly influences the amount of
N fertilizer required to optimize winter wheat yields! In order to detains the
availability of N at different depths in the root zone, and N placement ™udy was
conducted in the field on two soils in western Nebraska, a deep alluvial fine
sandy loam and a loess-derived silt loam. Ammonium nitrate was placed on the
soil surface and at depths of 30, 60, 90, 120, and 150 cm. Whea? plants were
harvested six times during the spring growing season to determine N uptake.
Soil moisture was at field capacity in the spring when experiments were estab-
lished. While N uptake tended to decrease as the depth of N application increased,
total dry matter production was not affected by depth of N placement. Wheat
plants easily obtained 'N placed at depths of up to 150 cm. The results indicate
winter wheat roots are mostly established during the fall growing season
and are in a position to provide N early in the spring for rapid above ground
growth. ^
DEFOLIATION AND FERTILIZER NITROGEN EFFECTS ON NITRATE-NITROGEN PROFILES IN MAIZE,
Hicks, D.R. and Peterson, R.H.
Minnesota University, Department of Agronomy and Plant Genetics, St. Paul,
Minnesota 55108
Agronomy Journal, Vol. 68, No. 3, p 476-478, May-June 1976. 3 fig, 10 ref.
Descriptors: Corn, Hail, Nitrate, Nitrogen, Fertilization
Corn vegetative tissue remaining after hail damage is often utilized for forage.
Environmental stresses may cause levels of nitrate-nitrogen in plant tissue that
are toxic to ruminants. This study was conducted to determine the effect of leaf
blade removal (simulated hail damage) and N fertilization of the soil on the NO-3-
N profile of corn fodder. Leaf blade removal of 0, 50, 100% was imposed at
tasseling on the corn hybrid 'Dekalb XL45A' grown in soil fertilized with either
115 or 230 kg N/ha. Plants were sampled approximately weekly for 6 weeks after
defoliation.
76:03F-090
EVALUATION OF SULFUR-COATED UREA (SCU) APPLIED TO IRRIGATED POTATOES AND CORN,
Liegel, E.A. and Walsh, L.M.
Wisconsin University, Department of Soil Science, Madison, Wisconsin.
Agronomy Journal, Vol. 68, No. 3, p 457-463, May-June 1976. 4 fig, 5 tab, 9 ref.
Descriptors: Potatoes, Corn, Nitrogen, Fertilizers, Fertilization, Wisconsin,
Leaching, Irrigation, Irrigation effects. Urea.
Excessive rates of soluble N fertilizers are sometimes used on irrigated sands in
Central Wisconsin to compensate for loss of some of the applied N by leaching.
Use of a slow-release form of N or several small applications of a soluble N fer-
tilizer may eliminate some leaching and subsequent loss of N03-N. This study was
designed to evaluate these methods of reducing N losses by measuring yield and
recovery of applied N by potato tubers and corn grain. Supplemental N treatments
applied each year for 3 years were as follows: 1) urea in a single or split
application, 2) SCU impregnated with a wax coating, and 3) SCU with only a sulfur
coating.
76:03F-091
SALT TOLERANCE OF PROSTRATE SUMMER CYPRESS (KOCHIA PROSTRATA) ,
Francois, L.E. ,. TT . . ,
Agricultural Research Service - United States Department of Agriculture, United
States Salinity Laboratory, P- 0. Box 672, Riverside, California 92502.
Agronomy Journal, Vol. 68, No. 3, p 455-456, May-June 1976. 2 tab, 9 ref.
Descriptors: Salinity, Saline soils, Salt tolerance, Greenhouse experiments,
Sodium, Chloride, Rangelands.
Prostrate summer cypress, a widely distributed perennial shrub in Russia, ^
imported into the USA to determine its potential as an acceptable forage on the
western rangelands. Since considerable acreage of its possible habitat contains
147
-------
salt-affected soils, a salt tolerance study was done to determine how well suited
it was to these saline areas. Two accessions of prostrate summer cypress were
tested using soil cultures in the greenhouse. Salinity levels used were 2, 7,
11, and 17 mmhos/cm. The plants were harvested six times over a 3-year period.
Both accessions proved to be very salt tolerant but one was significantly more
productive than the other at all salinity levels. Although sodium and chloride
contents approached 50 and 85 meg/100 g dry matter, respectively, no salt injury
symptoms were visible. Sodium uptake increased proportionately with increasing
salinity, whereas chloride uptake was less dependent on salt concentration and
appreciably greater than that of sodium. Since both accessions proved to be highly
salt tolerant, they should be well adapted for planting in the salt-affected
western rangelands.
76:03F-092
SEED COATING, PRECISION PLANTING, AND SPRINKLER IRRIGATION FOR OPTIMUM STAND
ESTABLISHMENT,
Robinson, F.E. and Mayberry, K.S.
California University, Cooperative Extension, Department of Water Science and
Engineering, California
Agronomy Journal, Vol. 68, No. 4, p 694-695, July-August 1976. 2 tab, 7 ref.
Descriptors: Lettuce, Sugar beets, Sprinkler irrigation, Germination, Carrots,
Onions, Seeds, Irrigation effects, Irrigation practices.
The legal prohibition of the short handled hoe in California has forced a change
in the conventional practice of surplus-seedling and subsequent thinning to achieve
optimum stands with lettuce and sugar beet crops. Precision placement of coated
seed was evaluated as an alternate method of stand establishment with five crops
grown on Meloland sandy clay loam with sprinkler irrigation. Germination was
compared to emergence of coated seed. Emergence was: carrot 86%, onion 85%, and
sugar beet 71%. Single lettuce seeds 38 cm apart had 89% stand, paired seeds
2.5 cm apart on 38 cm intervals and thinned had 97%.
76:03F-093
CHANGES IN TOTAL N, ORGANIC MATTER, AVAILABLE P, AND BULK DENSITIES OF A CULTIVATED
SOIL 8 YEARS AFTER TAME PASTURES WERE ESTABLISHED,
White, E.M., Krueger, C.R., and Moore, R.A.
South Dakota State University, South Dakota Agricultural Experiment Station,
Department of Plant Science, Brookings, South Dakota 57006
Agronomy Journal, Vol. 68, No. 4, p 581-583, July-August 1976. 2 tab, 9 ref.
Descriptors: Nitrogen, Organic matter, Phosphorus, Bulk density, Soil investi-
gations, South Dakota, Pastures,_Alfalfa.
Cultivated Williams loam soils in north-central South Dakota were sampled after
pastures were established and 8 years later so that the effect of the pastures on
soils could be studied from analysis in the laboratory. Pastures were seeded to
Russian wildrye, crested wheatgrass, or a mixture of smooth bromegrass, intermed-
iate wheatgrass, and a pasture alfalfa. Soil N and bulk densities increased as
available P decreased in the 8 years. The soil organic matter increased under
all pastures, but it was small. The increases in organic matter, decreases in
available P, and increases in saturated-clod bulk densities were different in
the various pastures. Total N and organic matter increased about 0.001 and 0.02%
per year, respectively, which is slower than the rate of decrease caused by cul-
tivating the original grassland soils.
76:03F-094
EFFECT OF LEAF SHAPE ON RESPONSE OF COTTON TO PLANT POPULATION, N RATE, AND IRRI-
GATION,
Rao, M.J. and Weaver, J.B. Jr.
Georgia University, Department of Agronomy, Athens, Georgia 30602.
Agronomy Journal, Vol. 68, No. 4, p 599-601, July-August 1976. 4 tab, 8 ref.
Descriptors: Leaves, Cotton, Crop response. Irrigation, Irrigation practices,
Nitrogen, Fertilization.
148
-------
Leaves varying in shape have been identified in cotton
that leaf shape affects growth and other '
ecnaracernplanoton
The objective of these studies was to evaluate okra and normal leaf shape on boll
rot, yield, earliness, boll size, and fiber properties. Near isogenic lines of
okra and normal leaf shape cotton was evaluated at three plant populations and
three N rates on an Appling coarse sandy loam soil over a 3-year period 1971-73
in 1972 irrigation treatments were also included. No significant interactions '
were found between leaf characters, plant populations, N rates, and irrigation
Okra leaf shape increased earliness, boll size, and micronaire and decreased seed
cotton loss due to boll rot. With increasing plant populations, lint yield and
earliness tended to increase and boll size decreased. Higher boll rot loss was
observed at higher levels of N. Irrigated cotton produced significantly greater
lint yield, boll size, and fiber length and increased earliness.
76:03F-095
HIGH-FREQUENCY TRICKLE IRRIGATION AND ROW SPACING EFFECTS ON YIELD AND QUALITY
OF POTATOES,
Phene, C.J. and Sanders, D.C.
Agricultural Research Service-United States Department of Agriculture, Florence,
South Carolina 29501
Agronomy Journal, Vol. 68, No. 4, p 602-607, July-August 1976. 6 fig, 4 tab, 15 ref.
Descriptors: Potatoes, Irrigation, Irrigation practices, Crop production. Soil
water stress, Soil water. Soil moisture.
Soil water is a major limiting factor in the production and quality of potatoes.
The objectives of this research were to determine the effects of trickle irrigation
under controlled soil matric potential and two row spacings on the yield, quality,
and nutrient contents of potatoes. Potatoes, trickle irrigated with nutrient solu-
tion and grown in 100-cm rwo spacing on sandy loam soil, yielded 76% more market-
able potatoes than those trickle irrigated under a plastic mulch and grown on twin
row spacing and 206% more than 100-cm spaced, nonirrigated potatoes.
76:03F-096
LATE SUMMER IRRIGATION AND ESTABLISHMENT OF WINTER ANNUAL LEGUMES IN A MEDITER-
RANEAN-TYPE CLIMATE,
Taggard, K.L., Delmas, R.E., and Raguse, C.A.
California University, Department of Agronomy, Davis, California.
Agronomy Journal, Vol. 68, No. 4, p 674-677, July-August 1976. 3 tab/7 ref.
Descriptors: Legumes, Clovers, Grasses, Ryegrass, Irrigation, Irrigation effects,
Irrigation practices.
Winter annual legumes have low fall and early winter forage yields in Califormia's
Mediterranean-type climate. A 2-year field study was conducted to determine the
effects of late summer irrigation on seedling development, forage yield potential,
and management problems of subterranean clover, rose clover, and bur clover. A
mixture of three annual grasses, slender wild oats, and annual ryegrass, and a
natural stand of indigenous species were included in the study for comparison.
By irrigation prior to fall rains, we subjected six successive seedings, 2 weeks
apart, to higher temperatures and longer fall-growth periods than usual.
76:03F-097
SOYBEAN ROOT DEVELOPMENT AND SOIL WATER DEPLETION,
Stone, L.R., Teare, I.D., Nickell, C.D., and Mayaki, W.C.
Kansas State University, Department of Agronomy, Evapotranspiration Laboratory,
Manhattan, Kansas 66506 r • t » r
Agronomy Journal, Vol. 68, No. 4, p 677-680, July-August 1976. 6 rig, 14 ret.
Descriptors: Soybeans, Root development, Soil moisture, Soil water, Model studies.
149
-------
We conducted a field study to investigate soybean root growth and water depletion
patterns. Field water depletion and rooting data are needed to assist in develop-
ing and refining models that consider root-soil-water interactions. Irrigated and
nonirrigated soybeans were grown in a deep, barrier-free, Muir silt loam. Soil
water content, determined using neutron moderation, was used to calculate water
depletion rates. Soil water content and desorption curves were used to estimate
soil water potential. Available soil water was estimated using—15 bars soil
water potential as the lower limit of availability- We collected soil volumes
76 cm wide, 7.6 cm thick, and 180 cm deep and washed roots free using a 53-mesh
screen. During the first half of our study, maximum root and water depletion
depths were nearly equal. Later, water depletion tended to be about 15 cm deeper
than root growth (possibly as a result of upward water movement into the water-
depleted root zone).
76:03F-098
IRRIGATED AND NONIRRIGATED SOYBEAN, CORN, AND GRAIN SORGHUM ROOT SYSTEMS,
Mayaki, W.C., Stone, L.R., and Teare, I.D.
Kansas State University, Evapotranspiration Laboratory, Manhattan, Kansas 66506.
Agronomy Journal, Vol. 68, No. 3, p 532-534, May-June 1976. k fig, 1 tab, 4 ref.
Descriptors: Root distribution, Irrigation, Irrigation effects, Soybeans, Corn,
Grain sorghum. Furrow irrigation. Soil water.
Knowledge of rooting patterns of various crops is important in designing irriga-
tion systems and assessing water extraction capabilities. We investigated root
depth and distribution under irrigated and nonirrigated conditions for soybeans,
corn, and grain sorghum. Soil cores 6.7 cm in diam. were taken to 180 cm deep
in the crop row, 1/4 row, and 1/2 row (furrow) for each crop at physiological
maturity- The cores were sectioned in 30-cm increments and washed through 35-
mesh screen (0.73 mm opening), and the roots oven dried. The study soil was
deep, barrier-free, Muir silt loam (fine-silty, mixed, mesic, Pachic Haplustoll).
Approximately 71, 64, and 86% of the total root dry matter were in the upper 30
cm for nonirrigated soybeans, corn, and grain sorghum, respectively- Only corn
did not have roots in the 150 to 180-cm zone. Seasonal water uses under irrigated
conditions (neglecting water flux into or from the root zone) were 65 cm, 65 cm,
and 53 cm in soybeans, corn, and grain sorghum, respectively. Seasonal water
use was approximately 44 cm by each of the three crops under nonirrigated
condition's.
76:03F-099
EVALUATION OF NONUNIFORMITY IN IRRIGATION AND YIELD,
Varlev, I.
Academy of Agricultural Sciences, Agrophysics Laboratory, Sofia, Bulgaria
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR1, p 149-164,
March 1976. 6 fig, 1 tab, 15 ref.
Descriptors: Irrigation, Irrigation effects, Irrigation practices, Irrigation
efficiency, Crop production, Infiltration, Uniformity coefficient.
The nonuniformity of water distribution over an irrigated area is one of the basic
features for evaluation of irrigation quality. It has been established, that non-
uniformity of distribution influences crop yield from different parts of an irri-
gation water distribution and its' effect on crop yield and average infiltrated
depth. For definite relationships between the depth of infiltrated water and
yield crop, for arid, humid, and subhumid zones, a coefficient of the nonuniform-
ity is defined, characterizing both nonuniformity and yield depression caused by
nonuniformity of irrigation-water distribution.
76:03F-100
WATER MOVEMENT IN SOIL FROM TRICKLE SOURCE,
Hachum, A.Y., Alfaro, J.F., and Willardson, L.S.
Utah State University, Department of Agricultural and Irrigation Engineering,
Logan, Utah.
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR2, p 179-192,
June 1976. 9 fig, 3 tab, 10 ref.
150
-------
m°Veitlent' Soil water' Soil moisture, Soils, Soil
inves-
Trickle irrigation basically involves the slow application of water to the soil
at particular points where the water immediately enters the soil and spreads
through it without appreciable flow of free water on the soil surface?P One of the
basic research needs at the present time is to obtain more information about the
water distribution pattern under a trickle source for different soil types and
different discharge rates. The -soil type and rate of water application influence
the rate of horizontal and vertical water movement in the soil and the distribu-
tion of the water potential in the wetted soil zone. Efficient design, operation,
and management of a trickle irrigation system require a full understanding of
these factors. The objective of this research was to: (1) study water movement
and distribution in homogeneous soil profiles under various rates of water appli-
cation from a surface trickle line source; and (2) utilize the results for prac-
tical use. r
76:03P-101
CONSERVATION TILLAGE - EFFECTS ON CROP PRODUCTION AND SEDIMENT YIELD,
Mannering, J.V., Johnson, C.B., and Wheaton, R.Z.
Purdue University, Agronomy Department, Lafayette, Indiana.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 16 p, 11 tab, 10 ref.
Descriptors: Soil erosion, Crop response, Crop production, Erosion, Corn, Soy-
beans.
Although tillage systems that leave appreciable crop residues on the surface effec-
tively reduce soil erosion, they can result in reduced crop yields on poorly
drained soils. Data are presented that illustrate the erosion control effec-
tiveness of various tillage systems following corn and soybeans.
j76j03F-102
"SSsG^ (HOT WATER) STORAGE IN GROUNDWATER AOUIFRRS,
EbeT-ing, L.L. and Reddell, D.L.
Texas A and M University, Department of Agricultural Engineering, College Station,
Texas .
Presented at the JL976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 27 p, 7 fig, 1 tab, 26 ref.
Descriptors: Groundwater, Groundwater aquifers. Model studies, Aquifers, Ground-
water management, Energy conversion, Energy -
A concept of storing hot water produced by solar collectors during the summer in
groundwater aquifers is presented. The hot water would be pumped to the surface
and used for space heating during the winter. The quantity of hot water capable
of being produced at various areas in Texas and the aquifer availability for hot
water storage is discussed. A numerical model to evaluate heat and mass transfer
in the aquifer is developed.
76-.03F-103
VERY- LOW- PRESSURE SPRINKLE IRRIGATION,
Burt, C.M. and Keller, J.
Utah State University, Department of Agricultural and Irrigation Engineering,
Logan, Utah. . .
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 24 p, 8 fig, 4 tab, 4 ret,
1 append.
Descriptors: Sprinkler irrigation, Irrigation, Irrigation systems, Irrigation
practices, Irrigation engineering.
Tests were conducted on the available sprinklers which can be °Per^ at pres-
sures of less than 4/3 atmosphere. Operating characteristics and design recommen
dations for the 'best sprinkler' from each of the four types of very-low-pressure,
151
-------
VLP, sprinklers are presented. The four types include: spray heads, perforated
pipe, reaction rotated sprinklers, and impact rotated sprinklers. The impact
sprinkler appears to be superior for VLP operation and merits further develop-
mental effort.
76:03F-104
FOOD PRODUCTION POTENTIAL FROM HOME GARDENS,
Smith, S.W. and Walker, W.R.
Colorado State University, Department of Agricultural Engineering, Fort Collins,
Colorado
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 11 p, 3 fig, 2 tab, 5 ref.
Descriptors: Food abundance, Foods, Mulching.
Developments in American agriculture are often applicable to home gardens. Tech-
nologies such as drip irrigation, mulching with black polyethylene sheeting, and
intensive cultivation practices may be utilized by the gardener. Through these
technologies the necessary labor input can be minimized and even a small garden
can materially offset a family's food budget.
76:03F-105
GRASSLAND RENOVATION - CONSERVES SOIL AND ENERGY AND INCREASES RETURNS FROM GRASS
FIELDS,
Smith, E.M. and Evans, J.K.
Kentucky University, Department of Agricultural Engineering, Lexington, Kentucky.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 12 p, 1 fig, 3 tab, 14 ref.
Descriptors: Grasslands, Soil erosion, Fertilization, Nitrogen, Legumes.
A grassland renovation seeder has been developed to interseed legumes into exist-
ing grass fields. This seeder disturbs less than ten percent of the grass sod.
Most of the sod remains to prevent soil erosion, even on steep slopes. Grass
fields which were renovated with a grassland renovation seeder by planting 6
pounds of red clover seed per acre required an energy investment of 0.023 times
1,000,000 KCal. per acre each year. Nitrogen fertilization of grass fields re-
quires an energy input of 55 KCal. as compared with each KCal. of energy input
when the new grassland renovation unit is used instead of nitrogen. Potential
returns in the form of beef produced on the grass fields per 100 brood cows was
increased from 25,272 pounds with nitrogen fertilization to 40,112 pounds with
grassland renovation to obtain a clover grass mixture. Grassland renovation
yielded 1.59 pounds of beef for each pound with nitrogen fertilization.
76:03F-106
THE CORNER SYSTEM - A VARIABLE RADII CENTER PIVOT SYSTEM,
Frankenstein, R.L.
Valmont Industries, Incorporated, Irrigation Products Division, Valley, Nebraska.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 12 p, 5 fig.
Descriptors: *Sprinkler irrigation, Irrigation practices, Irrigation systems,
Irrigation efficiency, Irrigation engineering.
A center pivot irrigation system has been developed that distributes water con-
siderably beyond the reach of previous center pivots; thus, allowing the irriga-
tion of square, rectangular, and other non-circular field shapes. The system'
consists of an additional 'swing span1 attanced to the end of the basic center
pivot that extends and retracts to conform to field boundaries. The additional
pipeline, the swing span, is supported by one steerable drive unit that is .guided
around the field, in and out of corners, by tracking a signal emitted by a buried
signal wire. Sprinklers along the swing arm are controlled automatically to pro-
vide uniform water distribution under all parts of the system. This new concept
of self-propelled irrigation allows over 96% field coverage in most situations.
152
-------
n ^eloping the
76:03F-107
NEW 'LATERAL MOVE' SPRINKLER CUTS NO CORNERS,
Schleicher, J.
Irrigation Age Magazine, 1999 Shepard Road, Saint Paul Minnesota
Irrigation Age, Vol. 11, No. 1, 3 p, September 1976. 3 fig.
Descriptors: Sprinklers, Sprinkler irrigation, Irrigation, Irrigation practices.
A new sideroll sprinkler system has been developed to irrigate corn.
76:03F-108
OPTIMIZATION OF SUBUNIT DIMENSIONS FOR PRESSURIZED IRRIGATION SYSTEMS,
Oron, G. , Karmell, D., and Walker, W.R.
Colorado State University, Department of Agricultural Engineering, Fort Collins,
Colorado.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 11 p, 4 fig, 3 equ, 4 ref.
Descriptors: Optimization, Irrigation, Irrigation design, Irrigation systems,
Pipelines, Piping systems, Model studies, Computer models.
The sophistication in analyzing optimality in a pressurized irrigation system de-
sign has evolved from pipe sizing problems for complex evaluations of layout
alternatives, field dimensions, energy input, and operational criteria. The non-
linear, mixed-integer model developed gave interesting results to the more general
design questions, but its complexity precludes its use as a design tool for many
design applications, particularly where certain assumptions on field layout have
been made. Results given in this paper demonstrate two of the possible uses a
model like this may find feasible.
76:03F-109
ANALYSIS OF HIGH FREQUENCY FURROW IRRIGATION,
Walker, W.R. and Gerards, J.
Colorado State University, Department of Agricultural Engineering, Fort Collins,
Colorado.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 12 p, 5 fig, 2 tab, 9 equ.
Descriptors: Furrow irrigation. Surface irrigation, Irrigation, Irrigation sys-
tems, Irrigation practices, Infiltration.
The possibility of high frequency furrow irrigations is explored. Field data
demonstrate the difficulty in evaluating infiltration parameters. Analyses of
results indicate a number of advantages in high frequency furrow irrigations.
76:03F-110
IRRIGATION MANAGEMENT OF SHORT-SEASON, HIGH-DENSITY COTTON,
Mohammed, R.A. and Fangmeier, D.D.
Arizona University, Department of Soils, Water and Engineering, Tucson, Arizona.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 9 p, 4 tab, 17 ref.
Descriptors: Irrigation, Irrigation systems. Cotton, Soil moisture, Soil water,
Crop production, Crop response, Nutrients, Fertilization, Nitrogen.
It was concluded that an available soil moisture depletion of 50 to 55% at irri-
gation will give the highest yields for short-season, high-density cotton. This
is compared to about 65% for conventional cotton. Changing the scheduling cri-
teria during the season tended to reduce yields. Application of 100 pounds of
153
-------
N per acre appears adequate for the soils studied. This provided adequate nitro-
gen for plant growth but did not result in high., petiole nitrate values late in
the season. For highest yields irrigation termination should be based on obser-
vations of boll load and maturity- Later irrigations tend to delay boll opening
while terminating too early reduces yields and fiber quality. Careful monitoring
of soil moisture and plant condition is both necessary and satisfactory for irri-
gation scheduling. With experience, feel and appearance of soil moisture condi-
tion was quite adequate for irrigation scheduling. Other methods were more expen-
sive and time consuming but were no better than field observations. Yields were
comparable to those obtained with conventional cotton for the years studied.
Water requirements were similar to those for conventional cotton. Early termin-
ation reduced the number of irrigations by one and in 1974 reduced the yield by
17%.
76:03F-111
THE DEVELOPMENT OF A FURROW-MULCH RIDGER,
Richey, C.B. and Griffith, d.R.
Purdue University, Department of Agricultural Engineering, Lafayette, Indiana
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 18 p, 7 fig., 3 tab, 16 ref.
Descriptors: Furrow irrigation, Surface irrigation. Erosion, Erosion control,
Furrows, Flow resistance, Flow, Soybeans.
A tillage tool to form ridges for row crops but leave residue on the surface in
the furrows has been developed. It gives promise of combining early plant growth
and weed control approaching plowing with moisture conservation and erosion con-
trol approaching the no-till system.
76:03F-112
BUDGET FOR YOUR NITROGEN IDEAL SUGARBEETS,
Westfall, D.G.
The Great Western Sugar Company, Agricultural Research Center, Longmont, Colorado
Crops and Soils Magazine, Vol. 28, No. 5, p 12-14, February 1976. 3 fig.
Descriptors: Nitrogen, Nutrients, Fertilizers, Fertilization, Sugarbeets, Crop
production, Agriculture.
This budget technique is a foolproof way of determining the fertilizer recommen-
dation for sugarbeets that is a vital link in efficient production. By using this
technique, you no longer have to apply nitrogen fertilizer blindly. You have a
technique that has proven itself by reaching the compromise of optimum yield of
high sugar content sugarbeets.
76:03F-113
BAND APPLICATION: A BETTER LESS COSTLY WAY TO FERTILIZE YOUR CROPS,
Richards, G.E.
Olin Corporation, Northern Regional Agronomy
Crops and Soils Magazine, Vol. 28, No. 9, p 10-11, August/September 1976
Descriptors: Fertilizers, Fertilization, Nutrients, Crop production. Agriculture.
Band application of phosphatic fertilizer or a combination of band plus broadcast
is the most efficient and most profitable way to apply fertilizer over both the
long or short term. Band application of phosphorus takes less fertilizer. Band-
ing reduces fertilizer costs, interest costs, and application costs. It may also
reduce fuel costs. Banding extends planting time by only 30 seconds per acre.
76.-03F-114
NEW ROW CROP DRIP IRRIGATION USE,
Hall, B.J.
California University, San Diego, California
Drip/Trickle Irrigation, Vol. 1, No. 1, p 26-27, June 1976. 5 fig.
154
-------
Sonf ?rrIg;tion1lfi^ieAcyfrigati0n PraCtices' Irrigation system, Crop produc-
The increase of drip irrigation over furrow application for row crops was substan-
tial last year, and it will make real inroads in 1976. Drip irrigation is expand-
ing rapidly in crops of staked tomatoes, strawberries, cucumbers, squash, peppers,
and soft squash. In San Diego County, tomatoes were irrigated last year with
several drip irrigation systems, and this year two to three thousand acres will be
in drip irrigation. Over 50 percent of the strawberry plantings in California are
in drip irrigation. The use of drip irrigation will expand into new lower gross
income crops for water savings and other benefits.
76:03F-115
FERTILIZER AND CHEMICAL INJECTION,
Schnedl, D.
Dymax Group
Drip/Trickle Irrigation, Vol. 1, No. 3, p 23-25, October 1976.
Descriptors: Fertilizers, Fertilization, Nutrients, Irrigation, Irrigation prac-
tices, Irrigation water.
The methods in general use for fertilizer and chemical feeding, in order of in-
creasing preference, are: 1) Simple metering into the irrigation water, 2) Use of
a venturi/bypass system, 3) A metering pump, 4) Proportionate feeding, using a
pump, pulse-generating flow meter and counter/timer control unit, and 5) Propor-
tionate feeding using a pump, flow meter with pulsed output and an SCR/variable
speed DC drive. The discussion applies to fertilizers, herbicides, algaecides,
chlorine and other chemicals.
76:03F-116
NITROGEN NOW AND TOMORROW,
Parker, J.H.
Tennessee Valley Authority, National Fertilizer Development Center, Tennessee
Crops and Soils Magazine, Vol. 28, No. 8, p 12-14, June-July 1976.
Descriptors: Nitrogen, Fertilizers, Fertilization, Nutrients.
We can expect to continue to have nitrogen fertilizers in the future. The domin-
ance of natural gas as a feedstock for ammonia production will diminish, being
supplemented by coal late in this century. Further in the future, processes based
on nuclear electricity and/or heat may become dominant. Other approaches that
now appear exotic could assume significance if researchers are able to manipulate
nature's secrets successfully. But we still face the possibility of short-term
scarcities when we have fast-changing market conditions.
76:03F-117
ONE DROP AT A TIME,
Flaherty, D.
Quest, Vol. 12, No. 4, p 4-9, Winter-Spring 1976. 8 fig.
Descriptors: Irrigation, Irrigation systems, Irrigation practices, Irrigation
water, Filters, Filtration.
With multiple demands increasing for a finite supply of water, the drip system of
irrigation has a lot more to offer, once some problems are solved Engineers and
Scientists at Washington State University are working on the problems.
76:03F-118
SUBTERRANEAN IRRIGATION,
Irrigation Journal, Vol. 26, No. 1, p 16-18, January-February 1976. 4 fig.
155
-------
Descriptors: Irrigation, Irrigation practices, Subsurface irrigation, Turf,
Turf grasses, Irrigation efficiency.
The PAT System involves the scientific construction of playing surfaces of natural
turf and soil over a perscribed mixture of sand to a depth of 16 to 24 inches.
Then a network of plastic pipe, with slits at uniform intervals, connected to
suction pumps controls the water flow (either off the field or onto the root
zone for irrigation). Electric heating cables can also be provided which will
extend the frost-free season and lengthen the turf growing season. Underneath
all this is the plastic sheeting which creates the barrier against underground
water rising to the playing surface. Presently this is a special ten-mil thick
vinyl sheeting welded together in massive sheets which are gate folded before
movement from the factory to the construction site. Properly engineered and
technically constructed, the PAT System promises to offer the answer to the many
faults of artificial turf and to provide a fine natural turf playing surface for
an extended season that can take a real beating without showing the damage of
athletic fields of yesterday.
76:03F-119
WEED MANAGEMENT TOOL HERBIGATION FOR IRRIGATED CROPLAND,
Siefert, W.
Nebraska University, Lincoln, Nebraska
Crops and Soils Magazine, Vol. 28, No. 5, p 10-11, February 1976. 2 fig, 1 tab.
Descriptors: Herbicides, Crop production, Irrigation, Irrigation practices,
Irrigation systems, Irrigation water.
If you irrigate, you have a good alternative to conventional ground or air chem-
ical applications for weed control. The alternative is herbigation—applying
herbicides through the irrigation system. Herbigation has been researched for
several years and is gaining acceptance among irrigators. Good results can be
obtained with herbigation in any type of irrigation system.
76:03F-120
DRIP SYSTEM APPLIES PHOSPHORUS,
Irrigation Journal, Vol. 26, No. 1, p 24, January-February 1976.
Descriptors: Irrigation, Irrigation practices, Phosphorus, Nutrients, Fertilizers,
Fertilization.
Results from recent University of California studies show that injection of phos-
phorus fertilizer through a drip irrigation system may be more feasible than
commonly thought.
76:03F-121
REMOTE SENSING OF SOIL MOISTURE,
Irrigation Journal, Vol. 26, No. 5, p 30-31, September-October 1976. 3 fig.
Descriptors: Soil moisture, Soil water, Remote sensing, Irrigation, Temperature.
Like physicians taking the temperature and blood pressure of human patients, 0.S.
Department of Agriculture scientists are testing the temperature and blood, or
sap pressure of plants, looking for clues that will indicate under what soil-
moisture conditions the plants are growing.
76:03F-122
LOW-COST 'BUBBLER1 IRRIGATION SYSTEM DEVELOPED,
Irrigation Journal, Vol. 26, No. 4, p 30, July-August 1976. 2 fig.
Descriptors: Irrigation, Irrigation systems, Irrigation efficiency, Water conser-
vation.
A simply installed, low-cost, low-pressure nearly maintenance-free system of
"bubbler" irrigation for tree crops is described.
156
-------
76:03F-123
FEASIBILITY OF USING SOLAR ENERGY TO DRIVE IRRIGATION PUMPS
Larson, D.L., Sands, C.D., II, TowleTC., Jr. and Fangemeier, D D
Arizona University, Department of Soils, Water and Engineering, Tucson, Arizona
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 18 p, 5 fig, 8 tab, 15 ref.
Descriptors: Irrigation, Irrigation practices, Solar radiation, Project plan-
ning, Irrigation engineering, Energy, Economics.
The technical and economic feasibility of using solar energy to drive irrigation
pumps have been studied to determine the conditions required for serviceable,
competitive use of solar systems. Solar power plant component development,
changes in irrigation and pumping practices, investment incentives and higher
fuel prices may all be required for economical use of solar energy.
76:03F-124
COMPUTERIZED IRRIGATION SCHEDULING METHOD MAY SAVE FARMERS MILLIONS OF DOLLARS,
Irrigation Journal, Vol. 12, No. 5, p 24-25, September-October 1976. 1 fig.
Descriptors: Irrigation, Irrigation practices, Water conservation, Computer
programs.
A new computerized method of irrigation scheduling which could result in a 30
to 35 percent savings in the state's water and energy requirements for irriga-
tion has been put on the Agriculture Computer Network (AGNET) by University of
Nebraska-Lincoln agricultural engineers.
76:03F-125
LOW-COST 'BUBBLER1 DEVELOPED,
Irrigation Age, Vol. 11, No. 1, p 20, September 1976.
Descriptors: Irrigation, Irrigation systems, Irrigation efficiency, Water con-
servation.
A simply installed, low-cost, low-pressure nearly maintenance-free system of
"bubbler" irrigation for tree crops is described.
76:03F-126
SPOON-FEEDING NITROGEN,
Irrigation Age, Vol. 11, No. 1, p 18-19, September 1976. 3 fig.
Descriptors: Nitrogen, Nutrients, Fertilizers, Fertilization, Crop production.
Producing a bushel of corn with one pound of fertilizer requires accurate soil
and water testing, skillful programming and a good understanding about nutrient
uptake of the corn plant. That is why a Colorado farmer is concentrating on
three areas which can help hedge against yield-depleting adversities: more
efficient nutrient programming, better water scheduling and improved tillage
techniques.
76:03F-127
DRIP/TRICKLE IRRIGATION GENERATING GROWTH, OPTIMISM,
Irrigation Age, Vol. 11, No. 3, p 14-16, November-December 1976. 1 fig.
Descriptors: Irrigation, Irrigation practices, Irrigation systems, Water con-
servation, Irrigation efficiency.
irrigation Age, in a series of personal interviews during the International Drip
irrigation Association meeting, spoke to several representatives of various drip/
trickle industry segments.
157
-------
76:03F-128
LOW-COST SAND AND GRAVEL SEPARATOR,
Humpherys, S.
Snake River Conservation Research Center, Kimberly, Idaho.
Irrigation Age, Vol. 11, No. 3, 1 p, November/December 1976. 2 fig.
Descriptors: Filtration, Irrigation, Sprinkler irrigation, Irrigation practices.
Many wells supplying sprinkler systems produce sand and small gravel in varying
amounts and sizes. Sand and gravel particles lodge in the sprinkler nozzles and
plug them. Anyone with such a well knows that continually unplugging nozzles
can be exasperating. Also, plugged nozzles affect water distribution and sand
in the water increases nozzle wear. Raymond Humpherys and his son, Jerry, who
sprinkle irrigate their dairy farm in Star Valley, Wyoming, experienced this
problem. To solve the problem, they purchased a 58-inch diameter, 442 gallon
buoy tank from a military surplus disposal year for less than $100. They con-
nected the buoy to the buried pipeline from their pump as shown in the drawing.
The 10-inch inlet pipe was welded into the tank just below mid-height and close
to one side. The outlet pipe was welded into the tank near the top. Water
flowing through system creates circulation motion causes a centrifugal force
which moves the heavier particles to the outside where the water velocity is
lower. The particles then settle to the bottom and accumulate in the center.
76:03F-129
EVAPORATIVE COOLING OF PEACH TREES TO BREAK REST AND DELAY BLOOM,
Chesness, J.L., Hendershott, C.H., and Couvillon, G.A.
Georgia University, Department of Agricultural Engineering, Athens, Georgia.
Paper No. 76-2039, Presented at the Annual Meeting of the American Society of
Civil Engineers, June 27-30, 1976. Lincoln, Nebraska, 12 p, 2 fig, 3 tab, 10 ref.
Descriptors: Peaches, Orchards, Sprinkler irrigation, Evaporation, Irrigation
systems, Irrigation effects, Irrigation practices.
The Utah Pheno-Climatography Model was used to predict rest completion and bloom
dates for Loring Peach Trees. Individual tree sprinklers with an application
rate of 0.086 per hour (0.218 cm/hr) were utilized over a 31-day period to achieve
a 14-day bloom delay.
76:03F-130
OPERATING LARGE TRAVELING 'GUN' SPRINKLERS IN WINDS,
Shull, H. and Dylla, A.S.
United States Department of Agriculture, Agricultural Research Service, Morris,
Minnesota 56267.
Paper No. 76-2014, Presented at the Annual Meeting of the American Society of
Civil Engineers, June 27-30, 1976, Lincoln, Nebraska. 5 tab, 8 ref.
Descriptors: Winds, Wind velocity, Irrigation efficiency, Uniformity, Irrigation
systems, Sprinkler irrigation, Minnesota.
Studies of the wind distortion of water application patterns from large single-
nozzle 'gun1 irrigation sprinklers in west central Minnesota, where high winds
are prevalent during the irrigation season, show that wind adversely affects the
application pattern. When 'gun' sprinklers are used as traveling sprinklers,
there is no acceptable travel lane spacing that will give a Cu value of 85% or
greater under all of the wind conditions to be expected in windy areas. Accept-
able water application uniformity can be achieved with wind velocities up to
about 25% of the no wind wetted diameter for the sprinkler, an unacceptable
solution. Limiting irrigation to periods when the wind velocity does not exceed
about 3 m/sec, and the wind direction is normal to the travel lane direction, will
usually produce a Cu value of 85% or more. In some areas average daytime winds
exceed 4 m/sec (9 mi/hr) during the cropping season, however, wind velocity usually
decreases at night. If night irrigation is possible it will provide a higher
Cu value than daytime irrigation because of the reduced wind velocity. If an
operator has a choice of travel land direction, the direction should be normal
to the prevailing wind direction.
158
-------
76:03F-131
AUTOMATION OF ON-FARM IRRIGATION TURNOUTS UTILIZING JACK-GATES
Dedrick, A.E. and Erie, L.J. '
United States Department of Agriculture, Agricultural Research Service, United
States Water Conservation Laboratory, 4331 East Broadway, Phoenix, Arizona 85040
Paper No 76-2049, Presented at the 1976 Annual Meeting of the American Society
of^Agricultural Engineers, June 27-30, 1976, Lincoln, Nebraska, 6 fig, 3 tab,
Descriptors: Basins, Irrigation, Irrigation systems, Irrigation efficiency,
Irrigation practices, Automation, Flood irrigation, Surface irrigation.
A 26.3 ha (65-acre) field, divided into eight level basins that are independently
irrigated from a centrally-located concrete-lined canal using single outlet jack-
gates, has been automated with pneumatic controls and air cylinders. The system
has been successfully operated for 14 irrigation cycles (May 1975 through May 1976)
The last 12 irrigations were completed by the farmer and/or his irrigator without
assistance from the developers/researchers.
76:03F-132
UNIFORMITY OF DISTRIBUTION IN UNDERTREE IRRIGATION IN ORCHARDS,
Karmeli, D. and Walker, W.R.
Technion - Israel Institute of Technology, Lowdermilk Faculty of Agricultural
Engineering, Haifa, Israel.
Paper No. 76-2012, Presented at the 1976 Annual Meeting of the American Society
of Agricultural Engineers, June 27-30, 1976, Lincoln, Nebraska, 14 p, 3 fig,
2 tab, 6 ref.
Descriptors: Sprinkler irrigation, Irrigation efficiency, Irrigation systems.
Irrigation, Uniformity, Orchards.
Sprinkler uniformity was evaluated in two citrus orchards using nozzles of varying
angles. Results were analyzed using the Christiansen Uniformity Coefficient as
well as the wetting zone technique. The effects of nozzle angle as well as fol-
iage density were determined.
76:03F-133
MINIMUM ENERGY DESIGNS FOR SELECTED IRRIGATION SYSTEMS,
Chen, K.L., Wolfe, J.W., Wensink, R.B., and Kizer, M.A.
Oregon State University, Department of Agricultural Engineering, Corvallis,
Oregon 97331
Paper No. 76-2037, Presented at the Annual Meeting of the American Society of
Civil Engineers, June 27-30, 1976, Lincoln, Nebraska, 7 fig, 5 tab, 6 ref.
Descriptors: Computers, Computer programs, Model studies, Simulation analysis,
Irrigation, Irrigation systems, Irrigation efficiency. Energy, Model studies,
Surface irrigation, Sprinkler irrigation.
A computer model has been developed which simulates the total energy requirement
and determines the designs requiring minimum energy consumption for various
irrigation systems. The model simulates each system by modularizing its energy
needs into four basic areas: installation, operation, transportation, and manu-
facturing. The model considers the total, non-renewable energy resources used
in the form of fossil fuel. Simulation model output determined the following
relatively consistent energy utilization hierarchy among the irrigation systems.
The effects of field size on minimum center pivot, permanent, and solid set sys-
tems. The effects of field size on minimum energy requirements for each irri-
gation system were relatively small but indicated that solid set and permanent
designs should be based on small scale fields, that hand move and side roll de-
signs reached minimum designs with 80-acre fields, and that drip and surface
systems' energy requirements remained relatively constant as the field sizes
were varied from 20 to 160 acres.
159
-------
76:03F-134
A LOOK AT CROP YIELDS ALONG THE COLORADO IN 2000 AD,
Robinson, F.E.
California University, Department of Land, Air and Water Resources, Water Science
and Engineering Section, Davis, California.
1976 Annual Technical Conference Proceedings, Sprinkler Irrigation Association,
Technology for a Changing World, February 22-24, 1976, Kansas City, Missouri,
p 131-132. 13 ref.
Descriptors: Technology, Irrigation, Crop production, Colorado River, Sprinkler
irrigation, Irrigation efficiency.
Technology is advancing into the changing world and is propelled from many direc-
tions. This change could improve yields along the Colorado because of improved
uniformity of the sprinkling and precision placement.
76:03F-135
MANAGEMENT FOR OPTIMUM EFFICIENCY,
Howell, T.A.
Texas A&M University, Department of Agricultural Engineering, College Station,
Texas 77843.
1976 Annual Technical Conference Proceedings, Sprinkler Irrigation Association,
Technology for a Changing World, February 22-24, 1976, Kansas City, Missouri,
p 79-88. 1 fig, 7 tab, 7 ref.
Descriptors: Irrigation water, Irrigation efficiency, Agriculture, Crop produc-
tion, Water quality, Optimization, Dynamic programming, Model studies.
The proper utilization of natural resources has never held a more prominent posi-
tion in our society than in these present times. The influence and effects of
water on the world food supply are extremely important. The irrigation water
utilized in agriculture in the future will probably be much lower in quality and
quantity than that found in present use. The proper management of these water
supplies will become increasingly important. This paper will focus on using high
frequency irrigation to maximize a crop yield with a limited quantity of irriga-
tion water. The purpose was to utilize existing soil water and precipitation in
conjunction with supplemental high frequency irrigation to increase crop yields.
The specific objectives of this paper are to optimize the irrigation decisions
under high frequency irrigation so that the maximum yield was obtained with a
given quantity of irrigation water. Dynamic programming was used to optimize
the multi-stage decision problem. System simulation was utilized to simulate
the stochastic state transitions.
76:03F-136
DRIP IRRIGATION - WORLDWIDE 1975 PRESENT STATUS AND OUTLOOK FOR DRIP IRRIGATION,
Gustafson, C.D.
California University, San Diego, California
1976 Annual Technical Conference Proceedings, Sprinkler Irrigation Association,
Technology for a Changing World, February 22-24, 1976, Kansas City, Missouri,
p 58-65.
Descriptors: Irrigation, Irrigation systems, Irrigation efficiency, Irrigation
practices, Orchards, Crop production.
The 1975 Worldwide Drip (Trickle) Irrigation Survey is the second such survey,.'
The first one in 1974 provided the first real look at what was happening to.drip/
irrigation in the United States and throughout the world. It is now over six . •
years since drip irrigation was introduced into California to be used on comme'r-
cial agricultural crops. The initial work began on an experimental five-acre
avocado orchard in northern San Diego County- Experimentation has spread to many
countries of the world and to most of the United States. Large scale plantings,
utilizing drip irrigation', of most agricultural crops, have gone in. In July,
1974, the 2nd International Drip (Trickle) Irrigation Congress was held in San
Diego, California. It was the culmination of five years of research, field test-
ing and growers using the new method of irrigation. Twenty-nine countries were
represented at the week long meetings, and with delegates from almost all the
160
-------
states of the U.S.A. in attendance. Over 100 technical papers were presented
and are contained in the Proceedings of the Congress. Sixty-five manufacturers
displayed their products in seventy booths. Opening day for the exhibits drew
2,000 people. One thousand persons registered for the Congress with each scien-
tific session drawing 800-900 growers, scientists, commercial company represen-
tatives and educators.
76:03F-137
SPRINKLER UNIFORMITY MEASURES AND SKEWNESS,
Chaudhry, F.H.
Excola de Engenharia de Sao Carlos, Deparamento de Hidraulica e Saneamento, Sao
Carlos (SP), Brasil
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR4 p 425-433
December 1976. 3 fig, 14 ref.
Descriptors: Sprinkler irrigation, Irrigation efficiency. Irrigation systems,
Irrigation design, Infiltration.
The relationships between the more popular measures of uniformity of sprinkler
irrigation have been studied both theoretically and experimentally taking into
account the skewness of the precipitation distribution. The theoretical results
show reasonable agreement with the data. Excellent agreement in the case of
pattern efficiency leads to the conclusion that the smaller precipitations are
well described by the assumed gamma distribution. The effect of skewness, in
general, is to increase the pattern efficiency and the coefficient of Christian-
sen. The linear relationships that exist between these parameters are conditioned
by the extent of skewness. This study shows that the conversion of one parameter
into another which is sometimes practiced in the design of sprinkler systems may
be risky if the skewness is disregarded.
76:03F-138
IRRIGATION TAILWATER LOSS AND UTILIZATION EQUATIONS,
Schneider, A.D.
United States Department of Agriculture Southwestern Great Plains Research Center,
Agricultural Engineering, Bushland, Texas.
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR3, p 461-464,
December 1976. 2 fig, 4 ref.
Descriptors: Tailwater, Irrigation, Furrow irrigation, Surface irrigation,
Irrigation systems, Return flow, Irrigation efficiency. Irrigation water.
Allowing irrigation tailwater runoff is the commonly accepted practice for fully
irrigating the lower end of graded furrows or borders. Irrigation-system water
losses are minimized by proper balance between tailwater losses and deep percol-
ation losses. Griddle et al. (3) recommended an irrigation advance time equal
to one-fourth of the application time. To reduce tailwater losses, they recom-
mended a 'cutback' furrow stream during the latter part of the irrigation set.
Irrigation tailwater recovery systems can reduce the water losses that occur
without a cutback furrow stream. Bondurant (2) presented design criteria for
tailwater recovery systems and recommended operating the systems to achieve a
reduced furrow stream input. A knowledge of the relative importance of design
variables and the ability to place bounds on tailwater loss and recovery aids
the engineer with limited design information. This paper develops equations
that show the relative importance of the variables affecting tailwater loss and
utilization.
76:03F-139
EFFECTS OF IRRIGATION SCHEDULING AND COORDINATED DELIVERY ON IRRIGATION AND
DRAINAGE SYSTEMS,
Gear, R.D., Dransfield, A.S., and Campbell, M.D.
United States Department of the Interior, Bureau of Reclamation, Lower Colorado
Region. . ,=
Presented at the National Water Resources and Ocean Engineering Convention of
the American Society of Civil Engineers, April 5-8, 1976, San Diego, California,
17 p, 3 fig, 3 ref.
161
-------
Descriptors: Scheduling, Irrigation, Irrigation practices, Neutron absorption,
Crop production, Soil moisture, Soil water, Irrigation efficiency.
A simple, accurate technique has been worked out to schedule irrigations, using
a graphic display of neutron probe measurements. The neutron probe design has
been changed to combine the sealer with the shield and provide a useful field
tool from what has traditionally been used almost exclusively for research. The
technique used for scheduling irrigation requires only the identification of the
refill point for each field and the neutron measured water content with time.
Evidence collected from 40 fields with 7 crops during the summer of 1975 shows
inconsistent irrigation timing with respect to available moisture. Consistent
timing alone could improve water use efficiency by more than 10 percent. The
neutron probe measurements of soil moisture depletion yield values of transient
water use by plants as well as transient water loss by drainage. These two values
together, divided by the water applied yield the efficiency for the field.
76:03F-140
DEVELOPMENT AND EVALUATION OF EVAPOTRANSPIRATION MODELS FOR IRRIGATION SCHEDULING,
Wright, J.L., and Jensen, M.E.
United States Department of Agriculture, Agricultural Research Service, Snake
River Conservation Research Center, Western Region, Kimberly, Idaho 83341
Paper No. 76-2063, Presented at the 1976 Annual Meeting of the American Society
of Agricultural Engineers, June 27-30, 1976, Lincoln, Nebraska, 11 p. 6 fig, 1 tab,
4 ref.
Descriptors: Evapotranspiration, Crop production, Irrigation, Micrometeorology,
Idaho, Lysimeters, Soil water, Beans.
Evapotranspiration (ET) from irrigated crops as a function of crop, soil and micro-
meteorological conditions has been studied for several years in the arid region
of southern Idaho. Earlier results were used to develop relationships for estim-
ating net radiation and potential ET as used in the USDA-ARS Computerized Irri-
gation Scheduling Program. Estimates obtained with the earlier relationships
are compared with recent measurements obtained with two sensitive weighing lysim-
eters. Procedures used in the development of crop curve relationships are pre-
sented for some of the crops studied to date. The performance of the scheduling
program in predicting the depletion of soil water for two years of irrigated
beans are presented to demonstrate the accuracy of the procedures. The importance
of obtaining representative meteorological data for irrigation scheduling is dis-
cussed.
76:03F-141
THE ROLE OF SIMULATION MODELS IN IRRIGATION SCHEDULING,
Jensen, M.E., and Wright, J.L.
United States Department of Agriculture, Agricultural Research Service, Snake
River Conservation Research Center, Western Region, Kimberly, Idaho 83341.
Paper No. 76-2061, Presented at the 1976 Annual Meeting of the American Society
of Agricultural Engineers, June 27-30, 1976, Lincoln, Nebraska, 14 p. 4 fig, 2 tab,
25 ref.
Descriptors: Simulation analysis, Model studies, Scheduling, Climatic data, Crop
production, Irrigation, Irrigation systems, Evapotranspiration, Colorado, Cali-
fornia, Idaho, Irrigation efficiency.
The role of simulation models in irrigation scheduling based on daily climatic
data is discussed. Simulation models provide tools that are valuable in the hands
of trained and experienced irrigation specialists. Also, simulation models are
needed by service groups to provide irrigation scheduling services at a reason-
able cost. A summary of factors affecting confidence levels in irrigation schedul-
ing is presented along with approximate magnitudes of the standard deviations to
be expected for each. Generally the error associated with the amount of irri-
gation water applied exceeds the error due to ET estimates until the field can
be monitored.
162
-------
76:03F-142
EVAPOTRANSPIRATION POTENTIAL UNDER TRICKLE IRRIGATION,
Walkerr W.R., Smith, S.W., and Geohring, L.
Colorado State University, Department of Agricultural Engineering, Fort Collins,
Colorado 80523.
Paper No. 76-2009, Presented at .the 1976 Annual Meeting of the American Society
of Agricultural Engineers, June 27-30, 1976, Lincoln, Nebraska, 22 p. 7 fig,
18 ref.
Descriptors: Evapotranspiration, Irrigation, Irrigation systems, Sdheduling,
Irrigation efficiency, Lysimeters, Peaches, Orchards, Soil moisture.
Predicting evapotranspiration under trickle irrigated systems has posed difficult
problems in scheduling and design because of the lack of generally applicable
information. A review of currently available mythodology is given along with
lysimeter studies to assess the state-of-the-art. Application of findings is
made to a young peaoVi orchard which is trickle irrigated by soil moisture sensors.
76:03F-143
MANAGING SALINE WATER FOR IRRIGATION,
Texas Tech University, International Center for Arid and Semi-Arid Land Studies,
Lubbock, Texas.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976. 618 p.
(see 76:05C-002)
163
-------
SECTION XIX
WATER QUANTITY MANAGEMENT AND CONTROL
CONTROL OF WATER ON THE SURFACE (GROUP 04A)
76:04A-001
MANNING'S ROUGHNESS FOR ARTIFICIAL GRASSES,
Graf, , W.H., and Chhun, V.H.
Ecole Polytechnigue Federals de Lausanne, Laboratoire d'Hydraulique, Switzerland.
Journal of the Irrigation and Drainage Division, American Society of Civil
Engineers, Vol. 102, No. IR4, Proceedings Paper 12603, p 413-423, December 1976.
8 fig, 2 tab, 9 ref, 2 append.
Descriptors: *Grasses, *Channels, *Roughness (Hydraulic), Roughness coefficient,
Reynolds number. Hydraulic properties, Hydraulics, Laboratory tests. Testing,
Equations.
Roughness of three types of artificial grass was investigated. Artificial grass
consists of a mattress that simulates the soil surface where groups of grass are
fixed in longitudinal and radial rows. The experiments were conducted in rectan-
gular and triangular laboratory flumes. The following conclusions can be drawn:
The n-value was found to be dependent on the flow depth and on the Reynolds num-
ber at low range of depths. The n-value was shown to be independent of the flow
parameters at a high range of depths. The constant roughness coefficient values
for the higher discharges were n = 0.032, n = 0.027, and n = 0.020 for the dif-
ferent artificial grasses. These n-values are in good agreement with the exper-
imental results for 'real1 grass found in the literature. It may be concluded,
therefore, that artificial grass will be a useful material when simulating grass
in the hydraulic laboratory.
76:04A-002
FIELD AND LABORATORY EVALUATION OF BI-LEVEL DRAINAGE THEORY,
Chu, S.T., and DeBoer, D.W.
South Dakota State University, Department of Agricultural Engineering,
Brookings, South Dakota.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 478-481, May-June 1976. 5 fig, 6 tab, 9 ref.
(See 02G-076)
76:04A-003
A THEORY OF FLOW RESISTANCE FOR VEGETATED CHANNELS,
Thompson, G.T., and Roberson, J.A.
Washington State University, Department of Civil and Environmental Engineering,
Pullman, Washington.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 2,
p 288-293, March-April 1976. 5 fig, 12 ref.
Descriptors: *Model studies, *Channel flow, *Flow resistance, Mathematical
models, Drag, Vegetation, Roughness (Hydraulic), Flow, Viscosity, Fluid
mechanics, Fluid friction, Hydraulics.
A theory was developed to predict the flow resistance in vegetated open chan-
nels. The solution technique was based on an analytical method originally pro-
posed by Roberson for smooth conduits roughened with discrete submerged roughness
elements. Flow conditions may either partially or fully submerge the cylinders.
Included in the analysis is a method to predict the effect of flexible vegeta-
tion on flow resistance. The model also predicts resistance effects of a
smooth boundary or one roughened by dense concentrations of small elements such
as soil particle aggregates. An initial comparison of flume measurements of
resistance for small diameter cylinders was given. The analytical model pro-
vides, in addition to resistance factor, other flow parameters involved in
analytical solutions of vegetated open channel flow.
164
-------
76:04A-004
OPERATIONS MODELS FOR CENTRAL VALLEY PROJECT,
Becker, I., Yeh, W.W.-G., Fults, D., and Sparks, D.
California University, Department of Engineering Systems, Los Anqeles
California.
Journal of the Water Water Resources Planning and Management Division,
Proceedings paper No. 12062, Vol. 102, No. WR1, p 101-115, April 1976
2 fig, 1 tab, 29 ref. OWRT C-5184 (No.- 4208) (3) .
Descriptors: *Water resources, *Multiple-purpose projects, *Decision making,
*Hydro-electric power, California, Optimization, Mathematical models,
Reservoirs, Planning, Management, Operations research, Algorithms, Water policy,
Linear programming. Dynamic programming.
System optimizing procedures are being developed for on-line use in the opera-
tion of the Central Valley Project in California, a complex multiple objective
water resource system. The project is subject to requirements and interagency
agreements. A practical optimization method must address not only these
requirements but also the continuing needs of day-to-day operation, and the
necessity for interposing the project managers in monitoring and final decision
roles. The basic technical diffulty with an optimizing algorithm for a complex
water resource system is the dimensionality which can easily run into the tens
of thousands of decision variables and constraints. The method being developed
for the project provides the necessary decomposition and involves the project
managers, assisted by an integrated group of multiple policies based on inter-
connected monthly, daily, and hourly models, using iterated linear programming-
dynamic programming techniques.
76:04A-005
A PROCEDURE FOR ESTIMATING OFF-SITE SEDIMENT DAMAGE COSTS AND AN EMPIRICAL TEST,
Lee, M.T., and Guntermann, K.L.
Illinois State Water Survey, Urbana, Illinois.
Water Resources Bulletin, Vol. 12, No. 3, p 561-575, June 1976. 5 fig, 3 tab,
22 ref.
Descriptors: *Agricultural watersheds, *Damages, *Costs, *Estimating, *Erosion,
*Reservoirs, Methodology, Equations, Recreation, Benefits, Flood damage,
Drainage, Storage, *Illinois, *Sediments.
Research was conducted to develop a methodology for estimating agricultural
off-site sediment damage costs and an empirical estimate of such damages for
a watershed is included. The economics of off-site sediment damage costs are
discussed as a theoretical basis for the procedures developed. A detailed
methodology is described for estimating five different types of off-site..sedi-
ment damages commonly associated with rural watersheds. The methodology is then
applied to a central Illinois watershed and estimates of individual types of
damage are made. The estimates are combined into an off-site sediment damage
function for the watershed, and the usefulness of the damage function for
analyzing off-site sediment damages and achieving a reduction in those costs is
discussed.
/
76:04A-006
OPERATION OF A RESERVOIR COLLECTING WATER FROM A SMALL WATERSHED,
Buras, N., Diskin, M.H., and Zamir, S.
Technion-Israel Institute of Technology, Lowdermilk Faculty of Agricultural
Engineering, Haifa, Israel.
Water Resources Research, Vol. 12, No. 5, p 866-872, October 1976. 5 fig,
6 tab, 3 ref.
Descriptors: *Reservoir operation, Optimization, *Economic efficiency,
Watersheds (Basins), Operations research, Synthetic hydrology, Storm runoff,
Decision making. Irrigation, Reservoir storage, Pumping, Costs, Benefits,
Equations, *Small watersheds.
Best operation policies, linear and nonlinear, were developed for a small
reservoir in which storm runoff water might be augmented by pumping water
from another source. These policies were aimed at a full reservoir at the
165
-------
beginning of the yearly irrigation season and, indirectly, utilized more
efficiently the existing neighboring pumping installations, which are usually
idle in winter. The operating policies are expressed as time-dependent
functions indicating the level of the reservoir which would ensure its being
full at the end of the rainy season with a given probability. When these
policies were tested with a synthetic hydrologic series of 45 years, it appeared
that the cost of operating the reservoir was inversely proportional to the
daily amount of water pumped into it from external sources.
76:04A-007
WIND EFFECTS ON WATER APPLICATION PATTERNS FROM A LARGE, SINGLE NOZZLE SPRINKLER,
Schull, H., and Dylla, A.S.
United States Department of Agriculture, North Central Region, North Central
Soil Conservation Research Center, Morris, Minnesota.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 501-504, Special Edition 1976. 4 tab, 7 ref.
Descriptors: *Sprinkling, *Sprinkler irrigation, Winds, Uniformity coefficient,
Irrigation, Irrigation practices, Irrigation effects, Irrigation systems.
This report describes a study to determine the effects of wind on the water
application pattern for a stationary, single nozzle, gun type irrigation
sprinkler. The effects of wind on application uniformity were determined by
comparison of the wind-affected application patterns with calculated no-wind
patterns. Deviation of the measured patterns from the no-wind patterns increased
as wind velocity increased. Stationary application patterns were used to calcu-
late the water distribution if the same sprinkler were traveling down lanes in
a field. The calculated distributions from a traveling sprinkler were then
overlapped with different travel lane spacings, and the Christiansen coefficient
of uniformity value determined for each spacing. A regression equation was
developed to give maximum travel lane spacing to obtain a coefficient of uniform-
ity value of 0.85 as a function of wind conditions and water pressures. Both
wind velocity and water pressure at the sprinkler elbow influence the water
distribution. Also, for a traveling gun, wind direction relative to travel
direction provides an additional affect; as the wind direction more nearly
approaches the travel direction, lane spacing must be decreased to maintain
acceptable application uniformity.
76:04A-008
SIMULATING OVERLAND FLOW IN BORDER IRRIGATION,
Bassett, D.L., and Fitzsimmons, D.W.
Washington State University, Department of Agricultural Engineering, Pullman,
Washington.
Transactions of the American Society of Agricultural Engineers, Soil and Water,'
p 666-671, Special Edition 1976. 3 fig, 2 tab, 15 ref.
Descriptors: *Border irrigation, *Surface irrigation, *0verland flow, Simulation
analysis, Mathematical models, Model studies, Irrigation, Irrigation systems.
A mathematical model of the border irrigation process is introduced. It is
based on the complete equations of continuity and momentum for unsteady,
spatially varied flow in open channels. The equations are solved approximately
by the method of characteristics. Simulated irrigation are compared to test
data. Agreement between simulated and observed data is generally satisfactory.
Applications of the model are suggested.
76:04A-009
SURFACE MODIFICATIONS FOR WATER MANAGEMENT AND SALINITY CONTROL IN A
NONIRRIGATED AREA,
Rektorik, R.J., Allen, R.R., and Lyles, L.
Agricultural Research Service, United States Department of Agriculture,
Department of Agricultural Engineering, Weslaco, Texas.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 699-703, Special Edition 1976. 6 fig, 2 tab, 15 ref.
Descriptors: Saline soil. Salinity, Leaching, Runoff, Surface runoff. Grain
sorghum, Cotton, Crop production, Salt.
166
-------
Leveling the saline soil areas in a field to a plane 9 era lower than that of the
nonsaline soil areas allows water from high intensity rains to run off from the
higher nonsaline soils and pond on the saline soils/thus providing leaching water
Original soil salinity for the 0-90 cm soil profile was reduced 53^o if percent
}?o™? B*1t2e n^Salin? areas' resPectively. Grain sorghum (1969) and cotton
(1970) yields were 47 and 38 percent greater than yields from an adjacent
untreated field.
76:04A-010
ESTIMATING SEEPAGE LOSSES FROM CANAL SYSTEMS,
Worstell, R.V-
Snake River Conservation Research Center, Department of Agricultural Engineering,
Kimberly, Idaho
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR1, p 137-147
March 1976. 5 fig, 3 tab, 22 ref.
Descriptors: Seepage, Canal seepage, Irrigation districts, Irrigation, Canals.
Seepage and operational losses from distribution systems are continuing problems
for designers and managers of irrigation districts and for water users. The
designer must provide sufficient capacity in the canals to allow for these losses,
and the managers must divert extra water into parts of the system to assure ample
flow to the lower reaches of all laterals. The water users must provide for ample
storage to offset problems that arise if seepage losses cause high water tables
in fields adjacent to the canal. As demands increase on all the water supplies
of the West, regional and state resource management agencies are looking critically
at the large volumes of water diverted by agriculture, especially when these vol-
umes are much larger than the amounts used in evapotranspiration. These agencies
need guidelines for more accurately determining reasonable water diversions to
irrigated agriculture. A simplified method that engineers and resource planners
can use to estimate seepage losses from new or existing canal systems is presented.
76:04A-011
LEAST COST IRRIGATION SYSTEM SPECIFICATIONS FOR VARIOUS CONDITIONS,
Busch, J.R.
Idaho University, Department of Agricultural Engineering, Moscow, Idaho.
Paper No. 76-2038, Presented at the Annual Meeting of the American Society of
Civil Engineers, June 27-30, 1976, Lincoln, Nebraska, 3 fig, 7 tab, 4 ref.
Descriptors: Model' studies. Simulation analysis, Optimization, Irrigation systems,
Economics, Irrigation efficiency. Water costs.
A methodology employing a dynamic-linear programming model was used to develop
optimum rehabilitation plans for an irrigation district. The plans developed
indicate the total irrigation system cost and configuration for various levels
of efficiency and water cost.
76:04A-012
CRITICAL IRRIGATION MANAGEMENT DECISIONS,
Corey, F.C. ;
Agricultural Technology Company, McCook, Nebraska.
1976 Annual Technical Conference Proceedings, Sprinkler Irrigation Association,
Technology for a Changing World, February 22-24, 1976, Kansas City, Missouri,
p 146-162. 3 fig, 5 ref.
Descriptors: Sprinkler irrigation, Irrigation, Furrow irrigation, Flood irriga-
tion. Irrigation systems, Irrigation practices, Crop production, Irrigation
efficiency.
With increasing land development and the millions of acreage already under sprink-
ler and gravity irrigation it is to the farmers interest (economically) to have
a good engineered irrigation system and see that it is managed and operated in
the most efficient manner to obtain maximum yields at the least cost. This irri-
gation system includes planning, development, maintenance and management ot tne
167
-------
well, the pumping system, and the sprinkler or distribution system. This paper
will be limited to sprinkler irrigation and pertain to: (a) brief introduction to
Ag Technology Co, (b) agricultural production, design and management problems
observed by this company over the last five to ten years, (c) irrigation manage-
ment techniques necessary to make critical irrigation decisions, and (d) any pos-
sible future trends and techniques necessary to management of our resources at
an optimum level.
76:04A-013
OPERATION AND MAINTENANCE OF IRRIGATION AND DRAINAGE SYSTEMS: SECTION IV.
MAINTENANCE,
The Committee of Operation and Maintenance of Irrigation and Drainage Systems
of the Irrigation and Drainage Division,
American Society of Civil Engineers,
Journal of the Irrigation and Drainage Division, Vol. 102, No. IRl, p 1-107, March
1976. 30 fig, 3 tab, 43 ref.
Descriptors: Irrigation operation and maintenance. Irrigation, Irrigation canals,
Irrigation ditches, Irrigation effects, Irrigation systems, Drainage effects,
Drainage practices. Drainage systems, Drains, Salinity.
The subject of maintenance is treated in this manual by a discussion of the factors
essential to keeping the facilities of an irrigation and drainage system in good
condition, the staff necessary to accomplish the work and that staff's responsibil-
ity, and common practices and procedures used for the maintenance of structures
and facilities pertinent to such systems. The irrigation systems referred to in
this section, are those generally associated with the movement of water from its
source to the user and which are prevalent in arid and semi-arid areas. The
drainage systems are those in which seasonal removal of water is normally a neces-
sity, due to possible water-logging of the soil, or the buildup of salts in it.
The system involved may be an essential part of an irrigation system in an arid
or semi-arid area or one of the larger and more extensive systems located in the
semi-humid or humid areas.
76:04A-014
AUTOMATION OF AN OPEN-DITCH IRRIGATION CONVEYANCE SYSTEM UTILIZING TILE OUTLETS,
Erie, L. J., and Dedrick, A.R.
United States Department of Agriculture, Agricultural Research Service, United
States Water Conservation Laboratory, 4331 East Broadway, Phoenix, Arizona 85040
Paper No. 76-2050, Presented at the 1976 Annual Meeting of the American Society
of Agricultural Engineers, June 27-30, 1976, Lincoln, Nebraska, 14 p. 5 fig, 5 ref.
Descriptors: Irrigation, Irrigation practices, Irrigation systems, Automation,
Basins.
An irrigation system on a 28.4 ha (70 acre) field divided into seven dead-level
basins, irrigated from a centrally-located concrete-lined canal, using modified
cylinders on jack-gates and structures utilizing air pillows or bellows, was
automated by use of pneumatic controls. A structure was designed that would
contain items pertinent to automation, so that turning the water into the field
and shutting it off would be automatically accomplished according to a predeter-
mined time schedule.
168
-------
SECTION XX
WATER QUANTITY MANAGEMENT AND CONTROL
GROUNDWATER MANAGEMENT (GROUP 04B)
76:04B-001
AQUIFER MANAGEMENT UNDER TRANSIENT AND STEADY-STATE CONDITIONS,
Alley, W.M., Aguado, E. , and Remson, I.
Stanford University, Department of Applied Earth Sciences, California.
Water Resources Bulletin, Vol. 12, No. 5, p 963-972, October 1976. 4 fig, I
tab, 7 ref.
Descriptors: *Aquifers, *Management, *Groundwater, *Linear programming,
*0ptimization. Wells, Distribution, Pumping, Decision making, Methodology,
Constraints, Mathematical models, Equations, Systems analysis.
The equations of transient and steady-state flow in two-dimensional artesian
aquifers are approximated using finite differences. The resulting linear dif-
ference equations, combined with other linear physical and management constraints
and a linear objective function, comprise a linear programming (LP) formulation.
Solutions to such LP models are used to determine optimal well distributions and
pumping rates to meet given management objectives for a hypothetical transient
problem for a steady-state field problem.
76:048-002
DRAWDOWN DUE TO PUMPING IN AN ANISOTROPIC AQUIFER,
Glover, R.E., and Moody, W.T.
Colorado State University, Department of Civil Engineering, Fort Collins,
Colorado.
Water Resources Bulletin of the American Water Resources Association, Vol. 12,
No. 5, p 941-950, October 1976. 3 ref, 1 append.
Descriptors: *Water wells, *Aquifers, *Drawdown, *Pumping, Permeability,
Artesian wells.
Formulas for water table or pressure drawdowns due to wells drawing water from
isotropic aquifers can be modified for use where the aquifer is nonisotropic.
The cases treated are those for a well drawing water from an aquifer at a con-
stant rate, for a well drawing water at a constant rate from an aquifer with a
'leaky roof, and for the flowing artesian well. In all cases the well is
considered to completely penetrate the aquifer. The resulting cones of depres-
sion formed from pumping an anisotropic aquifer has an oval shape. The length
of the major and minor axes of a contour of the cone of depression exhibit the
ratio Kx/Ky with Kx the direction of maximum permeabiltiy, and Ky in the direct-
ion ofminimum permeability, which lies at right angles to Kx.
76:048-003
A SIMULATION MODEL FOR OPERATING A MULTIPURPOSE MULTIRESERVOIR SYSTEM,
Sigvaldason, O.T.
Acres Consulting Services Limited, Niagara Falls, Ontario, Canada.
Water Resources Research, Vol. 12, No. 2, p 263-278, April 1976. 8 fig,
3 tab, 40 ref.
Descriptors: *Multiple-purpose reservoirs, *Reservoir operation,*Simulation
analysis, *0ptimum development plans. Water policy, Assessment, River basins.
Reservoir storage. Networks, Equations, Mathematical models, Systems analysis,
*Canada.
Described is a simulation model used for assessing alternative operating
policies for the Trent River system in Ontario, Canada. The Trent basin has
numerous reservoirs (48 were represented in the model). The reservoir system
is used for flood control, water supply, hydropower, and augmenting flows
through the canal system during the summer period. The need for assessing
alternative policies arose from growing conflicts in recent years ov« satisfy-
169
-------
ing all of the many water-based needs of the basin. The simulation model aided
in assessing the impact of alternative policies. Every reservoir was subdivided
into five storage zones (variable temporally). A time-based rule curve was
prescribed to represent ideal reservoir operation. Ranges were prescribed for
channel flows, which were dependent on water-based needs. The underlying con-
cept of the model was the mathematical representation of the chief operator's
perception of "optimum" operation and the derivation of this solution using a
nested optimization submodel. "Penalty coefficients" were assigned to those
varables which represented -deviations from ideal conditions. Different opera-
tional policies were simulated by representing the entire reservoir system in
"capacitated network" form and deriving optimum solutions for individual time
periods with the "out-of-kilter" algorithm. The algorithm was computationally
efficient, simplified model development, and permitted flexibility in readily
using the model for a wide range of reservoir configurations and operating
policies.
76:04B-004
FIELD DRAINAGE WITH MANIFOLD WELL POINTS,
Rektorik, R.J.
Agricultural Research Service, Weslaco, Texas.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 1,
p 81-84, January-February 1976. 2 fig, 4 tab, 6 ref.
(See 76:050-009)
76:04B-005
COST FUNCTIONS FOR ADDITIONAL GROUND WATER DEVELOPMENT,
Maddock, T. III.
Geological Survey, Water Resources Division, Reston, Virginia.
Water Resources Bulletin, Vol. 12, No. 3, p 539-545, June 1976. 2 tab, 9 equ,
6 ref.
Descriptors: *Groundwater, *Water resources development, *Water rights, Costs,
Energy, Industries, Equations, Operating costs.
In.many regions of the United States, the development of new water-intensive
industries for production of energy may upset the existing water rights structure,
Such an industry is coal gasification. This paper develops external cost
functions for determining compensation to esisting groundwater users when addi-
tional withdrawals are requested by new users. The functions reflect increased
energy costs, and as presented, they are based on a linear relation between
drawdown and pumping. It is assumed that the fixed cost of drilling and com-
pleting wells and the variable cost of operating wells overshadow the pipeline
company's compensatory payments. It is also assumed that the energy costs repre-
sent the profit losses to the original users. In conclusion, it should be noted
that compensation payment will result in costs to new users that are not trivial.
76:04B-006
MODEL-FREE STATISTICAL METHODS FOR WATER TABLE PREDICTION,
Yakowitz, S.
Arizona University, Department of Systems and Industrial Engineering, Tucson,
Arizona.
Water Resources Research, Vol. 12, No. 5, p 836-844, October 1976. 14 fig, 20
ref. NSF GK-35915, GF-38183.
Descriptors: *Water table, *Statistical models, *Depth, *Well data, *Arizona,
Water wells, Time series analysis. Stochastic processes, Statistical methods,
Homogeneity, Forecasting, Equations, Regression analysis. Water levels. Aquifer
characteristics.
In this study a new approach for predicting future values of well depths on the
basis of regional water table records was presented. Basically, well water
level depths are viewed as random sequences, and the assumption is made that
the region to be analyzed can be partitioned into several subregions of unknown
geographic shapes which are statistically homogeneous in the sense that the
record of each well in a fixed subregion is a different realization of the same
stochastic process. Methods from clustering and time series analysis were used
to find (1) the subregions of stochastic homogeneity, and (2) the statistical
170
-------
law for the same series of the wells in a given subregion. Forecasts were made
and confidence bands constructed by using the methods espoused here (in con-
junction with regression techniques) on Tucson basin data. The forecasts were
compared to depths actually observed, and, for many wells, the agreement was
sufficient to make these new methods appear promising.
76:048-007
PUMPING-TEST ANALYSIS USING A DISCRETE TIME-DISCRETE SPACE NUMERICAL METHOD
Rushton, K.R., and Booth, S.J.
Birmingham University, Department of Civil Engineering, (England).
Journal of Hydrology, Vol. 28, No. 1, p 13-27, January 1976. 11 fig, 3 tab
10 ref.
Descriptors: *Groundwater, *Pumping, *Numerical analysis, *Aquifer
characteristics, Wells, Computer models, Drawdown, Aquifer testing, Sand
aquifers, Head loss, Resistance networks. Unsteady flow, Computers, Water wells,
Turbulence.
The application of a digital computer model of radial flow in an aquifer to the
estimation of aquifer parameters was considered. Pumping-test data for a
shallow unconfined gravel aquifer, in which the drawdown recorded at the
pumped well is a significant proportion of the thickness of the aquifer, were
used to test the method. The model was sufficiently flexible to allow for
decrease in the saturated thickness, vertical components of flow, well losses
and variations of aquifer parameters in time and space.
76:048-008
PUMPING TEST ANALYSIS WHEN PARAMETERS VARY WITH DEPTH,
Rushton, K.R., and Chan, Y.K.
Birmingham University, Department of Civil Engineering, (England).
Ground Water, Vol. 14, No. 2, p 82-87, March-April 1976. 5 fig, 4 ref.
Descriptors: *Aquifer testing, *Data processing, *Depth, *Numerical analysis,
Computer models, Permeability, Storage coefficient. Aquifer characteristics,
Test wells, Limestones, Fissures (Geologic), Fracture permeability. Pumping,
Drawdown, Observation wells.
The analysis of pumping tests for the same borehole but with different rest
water levels may lead to significantly different values of aquifer parameters.
A numerical method of pumping-test analysis was introduced in which the
permeability and storage coefficient can take different values depending on
the current saturated depth. By introducing varying values of permeability and
storage coefficient, the numerical model was used to represent pumping tests in
a soft limestone aquifer.
76:04B-009
SHALLOW AQUIFERS RELATIVE TO SURFACE WATER, LOWER NORTH PLATTE RIVER VALLEY,
WYOMING,
Herrmann, R.
United States Department of the Interior, National Park Service, Southeast
Region, Altanta, Georgia.
Water Resources Bulletin, Vol. 12, No. 2, p 371-380, April 1976. 6 fig, 1 tab,
5 ref.
Descriptors: Ground water, Wyoming, Aquifers, Irrigation, Irrigation effects.
Pumping, Pumping plants, Model studies, Numerical analysis, Groundwater
recharge, Water resource, Alluvial aquifer.
The occurrence of ground water in the lower North Platte Valley, Goshen County,
Wyoming was studied to determine safe yield within the alluvial aquifer under
varying discharge and recharge conditions. The alluvium of the North Platte
is extensively developed for irrigation purposes and the effects of large-scale
pumpage'are of major concern. Actual withdrawals are estimated to be 46,000
acre-feet. Should pumping reach potentially higher levels an overdraft is
expected. Effect of ground water withdrawals are established from projections
of the flow regime within the alluvial aquifer. A time dependent, numerical
171
-------
model was employed to predict aquifer response to increased withdrawals. The
results suggest that more efficient use of surface waters and/or increased use
of ground water will reduce the annual subsurface return flow to the North Platte
River and its tributaries by an amount equal to the reduced groundwater increment.
Alternatives are available for management of the lower North Platte alluvial
aquifer. The preferred course is to correlate surface and subsurface water
rights, in light of convenience, economics, and best means of storage for maximum
utilization of the single water resource.
76:04B-010
ECONOMIC ANALYSIS OF ALTERNATIVE GROUNDWATER WITHDRAWAL RATES IN CONJUNCTION
WITH SURFACE WATER IRRIGATION,
Feldman, M., Whittlesey, N.K., and Butcher, W.R.
Washington State University, Pullman College of Agriculture.
Washington Water Research Center, Pullman, Report No. 27, September 1976. 126 p,
5 fig, 28 tab, 1 ref, append. OWRT B-051-WASH(2). 14-31-0001-3945.
Descriptors: Groundwater, *Withdrawal, *Conjunctive use, *Irrigation, Aquifers,
*Economics, *Groundwater mining, *Input-output analysis. Water level.
Eastern Washington is experiencing rapid decline in groundwater levels due to
irrigation pumping of the essentially fixes stock of groundwater. This study
develops a conceptual framework for comparing economic factors of the present
management policy to avoid exceeding a 10 foot per year decline in the static
water level with alternative policies allowing greater decline rates or augmenting
the water supply with surface water diverted from the Columbia River. A well cost
model was developed to provide estimates of water costs for every potential well
in the study area under alternative rates of water level decline. A computer
model of the groundwater aquifer was utilized to provide estimates of the amount
and location of the water that could be withdrawn from the aquifer while
remaining within the limits of any management policy. An agricultural model
(utilizing linear programming) calculated discounted net returns to agriculture,
including nonirrigated agriculture, over a 50 year period. An input-output
model was used to estimate the secondary economic impacts of additional irriga-
tion development that could result from alternative management policies. Results
showed that the actual depth from which water may be pumped depends heavily upon
the rate of decline and the static water level. If water levels are relatively
stable, water may be economically pumped from considerable depths. Rapid decline
rates in the static water level will reduce the absolute depth at which water may
be pumped economically. The results indicate that some economic gains would
accure to irrigated farms and the local economy under policies which encourage
more water use. However, the economic gains are proportionately much less than
the changes in water use required to induce the economic gain.
76:043-011
DESIGN OF GROUNDWATER LEVEL OBSERVATION-WELL PROGRAMS,
Heath, R.C.
Geological Survey, Water Resources Division, Raleigh, North Carolina.
Ground Water, Vol. 14, No. 2, p 71-77, March-April 1976. 4 fig, 2 tab.
Descriptors: Observation wells, *Network design, Hydrologic data. Discharge
measurement, Recharge, Measurement, Aquifers, Data collections. Water level
fluctuations, Water wells, *Withdrawal, *Groundwater recharge.
Data obtained from observation-well programs are used to determine: (1) the
effect of withdrawals on recharge and natural discharge conditions, (2) the
hydraulic characteristics of groundwater systems, and (3) the extent and degree
of confinement of aquifers. Wells in these programs can be divided into three
networks: (1) a hydrologic network which includes wells needed to determine the
extent of aquifers and changes in storage; (2) a water-management network-which
includes wells needed to determine the effect of withdrawals and hydraulic
characteristics; and (3) a baseline network which includes wells needed to
determine the response of groundwater systems to natural changes such as .those
related to climate.
172
-------
SECTION XXI
WATER QUANTITY MANAGEMENT AND CONTROL
EFFECTS ON WATER OF MAN'S NONWATER ACTIVITIES (GROUP 04C)
76:04C-001
WATER YIELDS RESULTING FROM TREATMENTS ON THE WORKMAN CREEK EXPERIMENTAL WATER-
SHEDS IN CENTRAL ARIZONA,
Rich, L.R., and Gottfried, G.J.
Rocky Mountain Forest and Range Experiment Station, Temple, Arizona.
Water Resources Research, Vol. 12, No. 5, p 1053-1060, October 1976. 8 fig,
2 tab, 12 ref.
Descriptors: *Water yield improvement, *Watershed management, *Arizona, Water
supply, Water yi&ld, Hydrology, Streamflow, Sedimentation, *Forest watersheds,
Burning, Lumbering, Grasses waterways, Pine trees, Surface runoff, Ponderosa
pinetrees. Instrumentation, Coniferous forests.
The three Workman Creek watersheds were instrumented to determine the hydrology
of mixed conifer forests and to determine the changes in Streamflow and sediment-
ation as a result of manipulating the forest vegetation. A small riparian cut
on North Fork did not increase water yield. A selection timber harvest, improve-
ment cut, and fire which removed 45% of the basal area on South Fork increased
water yields slightly. In contrast, converting 32.4 ha (80 acres) of moist for-
est site to grass significantly increased water yields on the 100.4 ha (248 acre)
North Fork watershed. Water yields were increased even more after 40.5 ha (100
acres) of dry-site pine forest were converted to grass. An increase of 69 mm
(2.70 inches), or 84%, of expected runoff resulted from the combined treatment.
Clearing 83% of the South Fork watershed preparatory to planting ponderosa pine
significantly increased water yields by 93 mm (3.67 inches), or by 111%.
173
-------
SECTION XXII
WATER QUANTITY MANAGEMENT AND CONTROL
WATERSHED PROTECTION (GROUP 04D)
76:040-001
LABORATORY TESTING OF WATER-REPELLENT SOIL TREATMENTS FOR WATER HARVESTING,
Fink, D.H.
Agricultural Research Service, Water Conservation Laboratory, Phoenix, Arizona.
Soil Science Society of America Journal, Vol. 40, No. 4, p 562-566, July-August
1976. 3 fig, 2 tab, 13 ref.
Descriptors: *Repellents, *Water harvesting, *Laboratory tests, *Soil treatment^
Watersheds (Basins), Soils, Water conservation, Arid lands. Erosion, Weathering,
Stabilization, Soil stabilization, Soil science.
Field testing of repellents for water harvesting is both slow and costly, often
hindering the orderly, rapid progression of the technique. Laboratory tests
were developed for rapidly evaluating the effectiveness of water-repellent treat-
ments on soils. The effect of accelerated weathering from ultraviolet radiation,
ozone, and freeze-thaw cycling on the retention of water repellency and on soil
stability was studied. The effect on soil stability of prolonged hydration and
water erosion was also considered. Using these laboratory tests, numerous soils,
organic materials, and' treatment techniques can be quickly evaluated so that
field testing can be reserved for only the most promising. A small, representa-
tive laboratory study, reported here to illustrate the technique, showed that
two repellents (a petroleum resin dust-suppressant oil and paraffin wax) when
combined made soil generally more resistant to total weathering effects than
did either repellent alone. The dust suppressant helped to stabilize the soil
against damage by freeze-thaw cycling, while the wax protected it from degrada-
tion by ultraviolet radiation. These laboratory results compared favorably with
observations form field plots treated with these two repellents.
76:040-002
EFFICIENCY OF NITROGEN, CARBON, AND PHOSPHORUS RETENTION BY SMALL AGRICULTURAL
RESERVOIRS,
Gill, A.C., McHenry, J.R., and Ritchie, J.C.
Agricultural Research Service, Sedimentation Laboratory, Oxford, Mississippi.
Journal of Environmental Qualiry, Vol. 5, No. 3, p 310-315, July-September 1976.
3 tab, 29 ref.
(See 76:02J-002)
76:040-003
A COMPARISON OF MODELING AND STATISTICAL EVALUATION OF HYDROLOGIC CHANGE,
Langford, K.J., and McGuinness, J.L,
Melbourne and Metropolitan Board of Works, Australia.
Water Resources Research, Vol. 12, No, 6, p 1322-1324, December 1976. 1 fig,
12 ref.
Descriptors: *Forest management, *Watersheds (Basins), Hydrology, *Statistical
models, *Model studies. Mathematical models, Reforestation, *Watershed manage-
ment. Lumbering, Surface runoff, Water yield, Runoff, Vegetation effects.
The U.S. Department of Agriculture Hydrography Laboratory model of watershed
hydrology is adapted for use on a research watershed where land use changed
drastically as a result of reforestation and subsequent thinning. Eight years
of measured runoff from a mature forest are used to estimate two of the mode"!
parameters; the remaining 39 are based on physical measurements, Model simula-
tions properly evaluated both the magnitude and statistical significance of the
hydrologic changes with much fewer data than were needed for standard statistical
analyses.
174
-------
76:040-004
SOIL AND WATER CONSERVATION WITH WESTERN IOWA TILLAGE SYSTEMS
Spomer, R.G., Piest, R.P., and Heinemann, H.G. '
Agricultural Research Service, North Central Watershed Research Center, Council,
Bluffs, Iowa. '
™ °f the A"16"0311 Society of Agricultural Engineers, Vol. 19, No 1
p 108-112, January-February 1976. 2 fig, 3 tab, 11 ref?
Descriptors: *Soil conservation, *Water conservation, *Erosion control, Culti-
vation, *Farm management, *Iowa, Runoff, Precipitation (Atmospheric) , Rainfall,
Crops, Corn (Field), Grasses, Terracing, Erosion rates, Cultivated lands, Sheet
erosion, Soil erosion. Watersheds (Basins) , Agricultural watersheds. Agricultural
runoff. Agriculture.
Excessive rates of surface runoff and erosion from the research watersheds at
Treynor, Iowa, were measured during a 10-yr study of two contour-planted water-
sheds cropped to corn. Low erosion rates occurred at a similarly cropped level-
terraced watershed and from a bromegrass watershed. These measurements showed
that level terraces and bormegrass are exceptionally effective conservation
practices. But level terraces with point rows and irregular fields complicate
farming and decrease farm machinery efficiency, and grass is not considered one
of the more profitable crops for western Iowa loess soils. Mulch- tilled corn
was also examined to assess its effect on surface runoff and soil loss. On one
watershed, mulch tillage was used with parallel terraces (double normal spacing).
The terrace-impounded water was removed by an underground drainage system, in-
stalled in the spring of 1972. The contour-planted watersheds lost more soil
than the mulch-tilled, parallel-terraced watershed in 1972.
76:040-005
CURRENT METHODS USED IN THE SOIL CONSERVATION SERVICE TO ESTIMATE SEDIMENT YIELD,
Nicholas, E.G.
Soil Conservation Service, Fort Worth, Texas.
Paper No. 76-2532, American Society of Agricultural Engineers 1976 Winter
Meeting, Chicago, Illinois, 8 p, December 14-17, 1976. 2 fig, 7 ref.
Descriptors: *Sediment yield, *Sedimentation rates, *Soil conservation,
*Estimating, Forecasting, Equations, Erosion, Soil erosion. Suspended load,
Deposition (Sediments), Methodology, Reservoirs, Land management, Farm
management, Aerial photography, Curves.
The four basic procedures currently used in the Soil Conservation Service to
estimate sediment yield depending on the environment and available data are:
(1) gross erosion and sediment delivery ratio estimates, (2) predictive
equations, (3) suspended sediment load measurements, and (4) sediment accumula-
tion measurements. For verification, it is desirable to use more than one
method .
76:040-006
STOCHASTIC APPROACH TO THE COLORADO RIVER BASIN,
Lane, W.L., Gibbs, A.E., and Main, R.B.
Water Utilization Section, Bureau of Reclamation, Denver, Colorado
Presented at the National Water Resources and Ocean Engineering Convention of the
American Society of Civil Engineers, 25 p, April 5-8, 1976, San Diego, California.
4 fig, 1 tab, 6 ref.
Descriptors: Hydrology, Rivers, River basins, River systems, Dissolved solids,
Water quality, Colorado river, Colorado river basin, Salinity.
The stochastic approach to hydrology may be successfully applied to large river
basins with several interdependent tributary inflows. Quality, specifically total
dissolved solids, may be successfully generated jointly with flow. In actual
application to the Colorado River Basin, results were obtained which are valuable
for planning and evaluation purposes. By using stochastically generated flows and
qualities, it is found that the effects of various structural or nonstructural
measures in the basin may be more realistically assessed under a variety of poten-
tial future flow and salinity conditions. If the measures had been analyzed with
175
-------
the set of historical flows and salinities, the assessment would have been incom-
plete and biased. This approach is expected to be applicable to other basins
with similar success.
176
-------
SECTION XXIII
WATER QUALITY MANAGEMENT AND PROTECTION
IDENTIFICATION OF POLLUTANTS (GROUP 05A)
76:05A-001
EVALUATION OF METHODS FOR PRESERVING THE LEVELS OF SOLUBLE INORGANIC PHOSPHORUS
AND NITROGEN IN UNFILTERED WATER SAMPLES,
Klingaman, E.D., and Nelson, D.W.
Purdue University, Agricultural Experiment Station, Lafayette, Indiana.
Journal of Environmental Quality, Vol. 9, No. 1, p 42-46, 1976. 3 tab, 11 ref
(See 76:07B-006)
76:05A-002
REGIONAL CHARACTERISTICS OF THE TOTAL DISSOLVED MINERALS IN STREAM WATERS IN
ILLINOIS,
Flemal, R.C., and Nienkerk, M.M.
Northern Illinois University, Department of Geology, DeKalb, Illinois.
Water Resources Bulletin, Vol. 12, No. 3, p 501-509, June 1976. 2 fig, 4 tab,
10 ref. S-046-ILL.
Descriptors: *Water chemistry, *Chemical analysis, *lllinois, *Dissolved solids,
*Natural streams, *Mineralogy, Analytical techniques. Water analysis, Water
quality, Water properties •, Streams, Rivers, Surface waters. Urban runoff,
Sulfates, Carbonates, Geology, Water pollution sources, Regions.
Using water analyses from 67 gaging stations, discharge-frequency-weighted mean
concentrations and average annual yield per unit area were determined for the
total dissolved mineral content of Illinois streams. The resultant data indi-
cated that total dissolved mineral contents are controlled by regional rather
than local factors. In most cases, plausible explanation for the magnitudes
could be found in regional patterns of natural and demographic conditions.
Although the data suggested that total dissolved minerals are increasing, the
relative contributions of natural versus anthropogenic phenomena were difficult
to delimit at this level of investigation.
76:05A-003
A SIMPLE TUBE-TYPE WATER PROFILE SAMPLER,
Gilbert, R.G., and Miller, J.B.
Agricultural Research Service, Water Conservation Laboratory, Phoenix, Arizona.
Water Resources Research, Vol. 12, No. 4, p 812-815, August 1976. 1 fig, 3 tab*
5 ref.
Descriptors: *Instrumentation, *Sampling, *Plastics, Farm ponds, Irrigation
canals, Lakes, Ponds, Dissolved oxygen analyzers, Chemical analysis, Tubes,
Water sampling, Agriculture, Pollutant identification.
A plexiglass tube-type water profile sampler was designed for use in relatively
shallow bodies of water, such as farm ponds, small recreational lakes, irrigation
canals, and the surface 2 m of larger lakes and rivers. The sampler was a plex-
iglass tube with holes drilled at intervals (side ports) corresponding to water
layers which were to be sampled. To obtain a water sample, the tube (open at
both ends and with the side ports closed) was gently lowered vertically into the
water. With the top stoppered, the tube was raised and its bottom stoppered
just under the water surface. While the tube was held vertically, the water
profile samples were rapidly and easily obtained after removing the top stopper
and successively collecting from top to bottom the water sample from each side
port. Dissolved oxygen (DO) profiles of the ponds measured with an oxygen probe
directly in the ponds were similar to DO profiles of water samples collected
with the tube sampler. Chemical and biological analyses of water samples ob-
tained with the tube-type sampler and two other standard type water samplers
(Kemmerer and Van Dorn) were compared. The analyses revealed that similar
relative results were obtained from water samples collected with all three sam-
plers, but the tube-type sampler was more desirable for obtaining water profile
samples because of its simplicity of design and operation especially in small
ponds.
177
-------
76:05A-004
A NOTE ON AN IN SITU GROUNDWATER SAMPLING PROCEDURE,
Spalding, R.F., Exner, M.E., and Gormly, J.R.
Nebraska University, Division of Natural Resources, Conservation and Survey,
Lincoln, Nebraska.
Water Resources Research, Vol. 12, No. 6, p 1319-1321, December 1976. 2 fig,
1 ref.
Descriptors: *Sampling, *Samplers, *Groundwater, Water pollution, Well casings,
*Pollutant identification.
In situ groundwater sampling can be a relatively economical procedure for measur-
ing time, spatial and vertical changes in groundwater quality. The sampling
technique cited allows large samples (1.1 liters) to be collected from a 2 foot
vertical interval of the groundwater column. This sampling technique allows the
quantification of the nature of groundwater contamination and allows for inter-
pretation of areal sources and the extent of contamination.
76:05A-005
DETECTION OF TRENDS IN WATER QUALITY DATA FROM RECORDS WITH DEPENDENT
OBSERVATIONS,
Lettenmaier, D.P.
Washington University, Department of Civil Engineering, Seattle, Washington.
Water Resources Research, Vol. 12, No. 5, p 1037-1046, October 1976. 11 fig,
3 tab, 12 ref, 1 append. NSF BMS74-20744.
Descriptors: *Water quality, *Time series analysis, *Statistical methods,
Analytical techniques, Statistics, Data processing, Monte Carlo method, Markov
processes, Temperature, Water temperature. Suspended solids, Conductivity, Water
pollution. Pollutants, Model studies.
Classical statistical tests for trend, both parametric and nonparametric, assume
independence of observations, a condition rarely encountered in time series
obtained by using moderate to high sample frequencies. A method was developed
for summarizing the power of the parametric t tests, the nonparametric Spearman's
rho test, and Mann-Whitney's test against step and linear trends in a dimension-
less "trend number" which is a function of trend magnitude, standard deviation
of the time series, and sample size. For the case of dependent observations,
use of an equivalent independent sample size rather than the actual sample size
was shown to enable use of the same trend number developed for the independent
case. An important related result is the existence of an upper limit on power
(trend detectability) over a fixed time horizon, regardless of the number of
samples taken, for a lag 1 Markov process.
76:05A-006
DESIGN AND OPTIMIZATION OF GROUNDWATER MONITORING NETWORKS FOR POLLUTION STUDIES,
Pfannkuch, H.O., and Labno, B.A.
Minnesota University, Department of Geology and Geophysics, Minneapolis.
Ground Water, Vol. 14, No. 6, p 455-462, November-December 1976. 6 fig, 2 tab,
5 ref.
Descriptors: *Network design, *Water pollution, *Groundwater, *Monitoring,
Waste disposal. Waste dumps. Networks, Planning, Wells, Observation wells,
Sampling, Leachate, Chemical analysis, Water pollution, Pollutants, Geology,
Leaching, Aquifers, Hydrogeology.
The successful design and operation of a groundwater monitoring and surveillance
system were based on a stepwide process of obtaining hydrogeologic information.
Because of the inherent uncertainty and inhomogeneity of natural hydrogeological
systems, the true monitoring network cannot be specified before some basic
knowledge about system configuration and dynamics is known. Forethought,
planning, and incorporation of design criteria as part of the initial phase
of project management establishes the monitoring network strategy- Optimization
of the monitoring network takes place through the completion of the following
five phases: (1) preliminary network design and information gathering,
(2) initial installation and testing, (3) completion and verification,
(4) operational, and (5) project termination. Experience gained from monitoring
178
-------
the conditions at the University of Minnesota's chemical and special waste
disposal site resulted in the design and optimization procedure. Concern for
possible groundwater contamination led to analysis of surface and subsurface,
physical and chemical conditions. Subsequently, a monitoring system was
established to meet project objective. No degradation of the groundwater
was found during the five-year study.
76:05A-007
MONITORING GROUND-WATER QUALITY NEAR A SANITARY LANDFILL,
Kunkle, G.R., and Shade, J.W.
Earthview, Incorporated, Toledo, Ohio.
Ground Water, Vol. 14, No. 1, p 11-20, January-February 1976. 8 fig, 2 tab,
18 ref.
Descriptors: *Water quality, *Groundwater, *Landfills, *Leachate, *Monitoring,
*Michigan, Groundwater Movement, Water pollution, Sulfur bacteria, Carbonates,
Chemical Degradation, Reduction (chemical), Oxidation-reduction potential, Path
of pollutants, Pollutants.
At the Ragman Road Landfill refuse is buried in lacustrine and glacial till
deposits consisting mainly of silty clays. These clays overlie a thick carbonate
aquifer used locally for water supply. The dominant direction of groundwater
flow is vertically down. Time of groundwater travel from the refuse to the
aquifer was estimated at 12 years, putting first arrivals in 1978. Water quality
monitoring of bedrock waters showed decreases in total dissolved solids,
sulfates, calcium, magnesium, chlorides, and total hardness with increases in
alkalinity to exist locally beneath the landfill. The principal chemical
reaction felt to explain some, but not all, of the water quality changes in
sulfate reduction. Theoretical geochemical modellings helped to support this
interpretation. The landfill was hypothesized to have either triggered or
accelerated sulfate reduction by creating the reducing environment.
76:05A-008
PROBLEMS IN PREDICTING AND MEASURING SOLUTE CONCENTRATIONS IN IRRIGATED FIELDS,
Jury, W.A., Fluhler, H., and Stolzy, L.H.
California University, Department of Soil Science and Agricultural Engineering,
Riverside, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 246-263. 11 fig, 4 tab, 5 ref.
Descriptors: Salinity, Salts, Root zone, Irrigation practices, Simulation anal-
ysis, Model studies.
The observed variation in salt concentration found between sensors at comparable
depths has been shown to be influenced far more by avriability in the water up-
take distribution than by changes in the assumed conductivity of the soil or by
input variations. This places severe restrictions on simulation of water and
salt movement within the root zone. At the same time, however, it suggests
that calculation of material transport below the root zone may not be as severely
limited by uncertainty in the soil transport coefficients as had previously been
suggested, provided that one can obtain reliable estimates of input water volumes
and plant and soil evaporation. Finally, the period of transition between new
and old irrigation management can be quite long, during which time reliance on
soil sensors to provide feedback for irrigation levels is likely to cause great
errors.
76:05A-009
WATER QUALITY AND RETURN FLOW STUDY OF THE OAHE UNIT, SOUTH DAKOTA,
Keys, J.W., III.
United States Bureau of Reclamation, Engineering and Research Center, Colorado
River Water Quality Office.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 109-126. 3 fig, 2 tab, 6 ref.
Descriptors: Water quality, Return flow, South Dakota, Simulation analysis,
Seepage, Dissolved solids, Water quality control.
179
-------
The Oahe Unit of the Pick-Sloan Missouri Basin Program will provide Missouri River
water for the irrigation of 190,000 acres of land in the James River Valley of
South Dakota. Computer simulation studies of the operation of the Unit were con-
ducted to estimate the quantity, quality, and timing of irrigation return flows
and determine their effects on the James River. This analysis included detailed
investigations of the irrigation water and lands to be irrigated, the major aug-
mentation releases of water to the James River, natural flow of the river, and
operation of project features for storage and regulation of water for irrigation
of the Unit. Under natural conditions, total dissolved solids (TDS) levels of
James River streamflow are relatively high, averaging about 786 mg/1 at Huron.
Study results show that TDS levels of the river could be maintained below 1,000 .
mg/1 (current South Dakota water quality standard for the river reach immediately
below the project) during the irrigation season, but concentrations during the
winter season would frequently exceed that level. Streamflow would be stabilized,
however, eliminating very low and highly concentrated flows.
76:05A-010
EFFECTS OF IRRIGATION LEACHING MANAGEMENT ON RIVER AND SOIL WATER SALINITY,
Saurez, D.L., and Rhoades, J.D.
United States Salinity Laboratory, Riverside, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 95-108. 5 tab, 8 ref.
Descriptors: Irrigation, Irrigation systems, Irrigation efficiency, Soil water,
Groundwater, River systems, River basins, Leaching, Salinity, Saline water.
Information about the effects of irrigation management on the changes in river
water, soil water, and groundwater quality associated with successive downstream
water diversion for representative types of river waters is provided. The depos-
ition of CaC03 and gypsum in entire river basins as a function of leaching frac-
tion is also considered.
76:05A-011
MANAGING SALINE WATER FOR IRRIGATION,
Texas Tech University, International Center for Arid and Semi-Arid Land Studies,
Lubbock, Texas.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976. 618 p.
(see 76:05C-002)
76:05A-012
VARIOUS INDICES FOR EVALUATING THE EFFECTIVE SALINITY AND SODICITY OF IRRIGATION
WATERS,
Oster, J.D., and Rhoades, J.D.
Unites States Salinity Laboratory, Riverside, California
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 1-14. 5 fig, 2 tab, 20 ref.
Descriptors: Irrigation water, Salinity, Saline water, Simulation analysis,
Model studies.
The salinity and sodicity haze—ds of irrigation water were evaluated by several
methods including residual sodium carbonate, pHc * and a computer cumulation of
gypsum and aragonite precipitation based on an assumed water uptake and PC02
distribution through the root zone. No useful correlation was found between the
computer predicted relative calcium and bicarbonate precipitation and residual
sodium carbonate. A correlation of r as similar or equal to 0.7 was found for
pHc*. Relative calcium precipitation was correlated, r as similar or equal to
0.8, with (CCa)(CS04), where C is concentration (meq/1) in the irrigation water,
when the product exceeded 30. The SAR's calculated from pHc* and the simulation
model, for the soil surface and bottom of the root zone, were also correlated,
r is equal to 0.99.
180
-------
76:05A-013
WATER QUALITY FOR AGRICULTURE,
Ayers, R.S., and Westcot, D.W.
California University, Department of Land, Air, and Water Resources, Davis,
California
Proceedings of the International Salinity Conference, Texas Tech University
Lubbock, Texas, August 16-20, 1976, p 400-431. 4 tab, 73 ref.
Descriptors: Water quality, Agriculture, Crop production, Salinity, Soil water,
Saline soil, Saline water, Leaching, Sodium, Water supply.
Salinity is discussed from the standpoint of a reduction in soil water availability
to crop. Updated crop tolerance tables for salinity of soil or of applied water
are presented. The newer leaching requirement concept of achievable represents
a considerable water saving as compared to the older LR procedures. Soil perme-
ability problems are associated with waters having either exceptionally low salin-
ity or high sodium. Excessive sodium is evaluated through a modification of the
sodium adsorption ratio (SAR), now termed 'adjusted SAR'. Specific ion toxicities
are related to the effects of boron, sodium or chloride on sensitive crips. A
few other effects are listed under "miscellaneous problems'. This paper is intend-
ed to provide guidance for project managers, farm operators, and general agricul-
turalists on problems related to on-farm water management and should be useful in
placing water quality effects in perspective with the other factors affecting crop
production, the ultimate goal being maximum production per unit of available water
supply.
76:05A-014
MINIMIZING THE SALT BURDEN OF PECOS RIVER IRRIGATION DRAINAGE WATER,
O'Connor, G.A., and Cull, C.
New Mexico State University, Department of Agronomy, Las Cruces, New Mexico
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 494-505. 9 fig, 2 tab, 5 ref.
Descriptors: Leaching, New Mexico, Lysimeters, Irrigation, Irrigation effects.
Evaporation, Water surface, Return flow, Drainage, Drainage effects.
A laboratory study was conducted to evaluate the potential of the minimized leach-
ing concept using synthesized Pecos River water on a New Mexico soil. Nine small
lysimeters were repeatedly irrigated at LFs of 0.1, 0.2, and 0.4 and exposed to
very high evaporative demands in an evaporation chamber especially designed for
the study. Results to date (after 50 irrigations) confirm that minimized leach-
ing results in considerable irrigation water savings and a simultaneous reduction
in drainage volume. Even after prolonged irrigation, steady-state conditions
have been reached in only the 0.4 LF treatment implying that changes in salt dis-
tribution as a result of instituting the minimized leaching program are very slow
to occur.
181
-------
SECTION XXIV
WATER QUALITY MANAGEMENT AND PROTECTION
SOURCES AND FATE OF POLLUTION (GROUP 05B)
76:05B-001
SURFACE RUNOFF LOSSES OF FERTILIZER ELEMENTS,
Dunigan, E.P-, Phelan, R.A., and Mondart, C.L. Jr.
Louisiana State University, Department of Agronomy, Baton Rouge, Louisiana; and
Louisiana Agricultural Experiment Station, Baton Rouge, Louisiana.
Journal of Environmental Quality, Vol. 5, No. 3, p 339-342, 1976. 6 tab, 9 ref.
Descriptors: *Nitrogen compounds, *Phosphorus compounds, *Fertilizers, *Nutrient
removal, *Agricultural runoff, *Louisiana, Nitrogen, Ammonia, Nitrates, Phos-
phates, Potassium compounds. Leaching, Potash, Runoff, Water quality. Water
pollution, Analytical techniques, Surface runoff, On-site investigations.
Surface runoff losses of•fertilizer N, P, and K were measured from a Loring silt
loam soil with an average slope of 5%. Plots seeded to pearl millet in 1973 and
1974 were fertilized at the rate of 112-49-93 kg/ha of incorporated N, P, and K
using two different fertilizer blends, a 33.3-8.7-16.6 and an 8-3.5-6.6. The
percent of water-soluble fertilizer elements lost in 1973 from the higher and
lower blend concentrations, respectively, were N, 0.50 and 0.30%; P, 0.14 and
0.06% and K, 0.67 and 0.92%. In 1974, N losses were 0.89 and 0.14%; P, 0.35 and
0.20%; and K, 0.42 and 0.35%. Precipitation during the experimental periods was
20.40 cm in 1973 and 27.69 cm in 1974. Ryegrass plots were fertilized with sul-
fur-coated urea (SCU) and uncoated urea (U) at the rate of 224 kg N/ha during
the growing seasons of 1973 and 1974. Total N losses (U \s.. SCU) were 9.52 and
0.26% in 1973, and 1.67 and 0.42% in 1974. A 10.08-cm rainfall on the third
day, of the test in 1973 caused almost three-fourths of the 9.52% N lost from
the uncoated urea to be lost in that runoff and while it was still in the urea
form. The sulfur coating prevented large surface losses of N from the SCU.
76:05B-002
NITROGEN IN SUBSURFACE DISCHARGE FROM AGRICULTURAL WATERSHEDS,
Burwell, R.E., Schuman, G.E., Saxton, K.E., and Heinemann, H.G.
Agricultural Research Service, Columbia, Missouri.
Journal of Environmental Quality, Vol. 5, No. 3, p 325-329. 1976. 4 fig, 3 tab,
15 ref.
Descriptors: *Nitrogen, *Subsurface runoff, *Agricultural watersheds, *Nutrient
removal, *N'itrogen compounds, *Iowa, Fertilizers, Leaching, Nutrients, Analytical
techniques, Percolation, Water quality, Groundwater, Nitrates, Soil erosion.
Water pollution sources, Soil conservation, Runoff, Watersheds (Basins), Conser-
vation, Sediment discharge.
The nitrogen in subsurface discharge and surface runoff was measured from four
agricultural watersheds on Missouri Valley deep loess near Treynor, Iowa, from
April 1969 through March 1974. The data showed that, with the agricultural
management practices used on the watersheds, the subsurface discharge of water
ranged from 62 to 88% of the average annual stream flow. Nitrate in subsurface^
discharge accounted for 84 to 95% of the total average annual soluble N discharged
in stream flow. A terraced watershed continuously cropped to corn had reduced
surface runoff, sheet-rill erosion, and associated nitrate-nitrogen discharge,
but had increased subsurface discharge of water and soluble N as compared with
two contoured corn watersheds. Nitrogen fertilizer applied at a high rate (448
kg/ha/year) exceeding crop needs on the terraced and contoured watersheds, in-
creased five- and threefold the average annual subsurface discharge of NO3-N,
respectively, as compared with a contoured watershed fertilized with N at a nor-
mal rate (168 kg/ha/year). Controlling the watershed discharge of N and subse-
quent pollution of stream flow from the Iowa and Missouri deep loess hills
requires N fertilizer application rates that do not exceed crop needs and using
conservation practices that minimize soil erosion and deep percolation.
182
-------
76:05B-003
GEOLOGIC NITROGEN IN PLEISTOCENE LOESS IN NEBRASKA,
Boyce, J.S., Muir, J., Edwards, A.P., Seim, E.G., and Olson, R A
Nebraska University, Department of Agronomy, Lincoln, Nebraska'
Journal of Environmental Quality, Vol. 5, No. 3, p 93-96, January-March 1976
3 fig, 1 tab, 15 ref.
Descriptors: *Nitrogen, *Nitrates, *Soil contamination, *Nebraska, *Soils
*Loess, Fertilization, Fertilizers, Agricultural chemicals, Water pollution,
Leaching, Irrigation, Cores, Soil chemical properties, Geology, Limestones
Shales, Groundwater.
Research into the relationship between fertilizer use and water quality in
Nebraska has resulted in the discovery of large quantities of geologic nitrate
within the deep loess mantle of southwestern and central Nebraska. The N03(-)
was first encountered at a depth of about 7 m and continued to an unknown depth
in excess of 30 m. Nitrate-N values of 25 to 45 ppm characterized the N zone,
but values to 87 ppm have been recorded. The N03(-) existed only under the more
level uplands of the region; however, it is on this plain that rapid development
of irrigation is taking place, and it has been shown that the N03(-) has been
leached from beneath older irrigation sites on the plain.
76:053-004
DISPOSITION OF FERTILIZER NITRATE APPLIED TO A SWELLING CLAY SOIL IN THE FIELD,
Kissel, D.E., Smith, S.J., and Dillow, D.W.
Texas Agricultural Experiment Station, College Station, Texas.
Journal of Environmental Quality, Vol. 5, No. 3, p 66-71,^January-March 1976.
4 fig, 3 tab, 19 ref.
Descriptors: *Nitrogen compounds, *Nitrates, *Fertilizers, *Leaching, *Soil
chemistry, Water quality, Analytical techniques, Leachate, Drainage, Nutrients,
Runoff, Subsurface drainage. Water pollution sources. Nutrient removal, Water
pollution, Percolation, Infiltration, Lysimeters, Drainage water, Grain sorghum,
Root zone, Path of pollutants.
This study was prompted by the present controversy over the role that N-fertil-
izer use may have in reducing water quality. The objective was to determine the
disposition of N fertilizer (enriched with 15N) applied to level (less than 2%
slope) Houston Black clay near the economic optimum application rate (112 kg N/ha)
for grain sorghum. Particular emphasis was placed on determining the amount of
applied N which leached below the root zone at different times during and after
the growing season. A large, undisturbed field-drainage lysimeter was used to
measure leaching of NO3(-)-N below the root zone. During spring 1973, 94 mm of
drainage water containing a mean concentration of 2.4 ppm fertilizer-derived
N03(-)-N percolated through the soil profile. At crop maturity, only 55% of the
N applied the previous spring was recovered by the crop or was present in drain-
age water. Large amounts of N not recovered by the crop were either measured as
immobilized N (20% of the applied N) or were unrecovered and assumed denitrified
(17%). During the fall and winter, approximately 120 mm of drainage water
containing 0.5 ppm or less fertilizer-derived N03(-)-N percolated through the
soil profile. These results indicated that for rainfall conditions observed in
this study (minimal crop water deficit), the application of N fertilizer to
grain sorghum at the near-optimum economic rate probably would not seriously
reduce groundwater quality on a swelling clay soil, even though crop recovery
of applied N might be low.
76:056-005
NITROGEN BALANCE IN THE SOUTHERN SAN JOAQUIN VALLEY,
Miller, R.J., and Smith, R.B.
California University, Department of Land, Air, and Water Resources, Water
Science and Engineering Section, Davis, California.
Journal of Environmental Quality, Vol. 5, No. 3, p 274-278, July-September 1976.
2 fig, 5 tab, 21 ref.
Descriptors: *Nitrate, *Nltrogen, *California.
A nitrogen balance for the southern San Joaquin Valley of California has been
calculated, using techniques and methodology developed for the Upper Santa Ana
183
-------
River Basin of southern California. The two areas differed considerably in
both size (the latter being much smaller) and agricultural function. Data were
compiled on N inputs, use, and outputs for many sources within the study area.
Such data enabled construction of a flow diagram depicting best estimates of N
pools and fluxes within the San Joaquin Valley Basin. Results show N inputs
into the study area from various sources were somewhat greater than output to
the atmosphere and by plant removal. Inputs to the soul N pool were about
9 kg/ha more in 1971 than in 1961. Since the soil N pool was estimated to be
about 11 metric tons/ha, this represented an increase of about 0.1%. However,
since the increases of N are not evenly distributed over the study area, high
N concentrations can develop in some local areas.
76:05B-006
RESIDUES OF DICHLOBENIL IN IRRIGATION WATER,
Bowmer, K.H., O'Loughlin, E.M., Shaw, K., and Sainty, G.R.
Commonwealth Scientific and Industrial Research Organization, Division of
Irrigation Research, Griffith, New South Wales, Australia.
Journal of Environmental Quality, Vol. 5, No. 3, p 315-319, July-September
1976. 3 fig, 4 tab, 15 ref.
Descriptors: *Herbicides, *Irrigation canals, Irrigation effects, Irrigation,
Aquatic weeds, Crop production.
Field trials were made on
-------
Nickel, Elements.
The processing of phosphatic shale near Pocatello, Idaho has a direct influence
on the element content of local vegetation and soil. Samples of big sagebrush
and cheatgrass show important negative relations between the concentration of
certain elements (Cd, Cr, F, Ni, P, Se, U, V, and Zn) and distance from phosphate
processing factories. Plant tissues within 3 km of the processing factories
contain unusually high amounts of these elements except Ni and Se. Important
negative relations with distance were also found for certain elements (Be, F R>
K, Li, Pb, Rb, Th, and Zn) in A-horizontal soil. Amounts of seven elements (Be
F, Li, Pb, Rb, Th, and Zn) being contributed to the upper 5 cm of the soil by
phosphate processing, as well as two additional elements (U and V) suspected as
being contributed to soil, were estimated, with F showing the greatest increase
(about 300 kg/ha) added to soils as far as 4 km downwind from the factories
The greatest number of important relations for both plants and soils was found
downwind (northeast) of the processing factories.
76:056-009
PHOSPHORUS LOSS BY STREAM TRANSPORT FROM A RURAL WATERSHED: QUANTITIES,
PROCESSES, AND SOURCES,
Johnson, A.H., BOuldin, D.R., Goyette, E.A., and Hedges, A.M.
Pennsylvania University, Philadelphia, Pennsylvania.
Journal of Environmental Quality, Vol. 5, No. 2, p 148-157, April-June 1976.
12 fig, 5 tab, 12 ref.
Descriptors: *Phosphorus, *New York, Low flow. Surface runoff, Sediments,
Farm waste. Sampling, Watersheds (basins), Land use.
Loss of dissolved and particulate phosphorus by stream transport was determined
over a 20-month period for Fall Creek, a stream draining a predominantly rural
watershed of 330 sq km in central New York. Samples were taken several times
daily during most high flow periods and at 3 to 20 day intervals during low
flow periods. Samples were ususlly processed within 4 hours since redistribu-
tion of P among chemical forms was rapid. Losses of P from the watershed per
unit time varied by several orders of -magnitude and 75% of the P loss occurred
in the major point source inputs, dissolved inorganic P concentrations were
highest during storm events due to two processes: desorption of P accumulated
in the bed sediment from point source inputs during low flow, and inputs from
diffuse sources in surface runoff. Dissolved organic P concentrations were
not correlated with flow. Approximately 20% of the dissolved P lost from the
watershed was derived from diffuse sources associated with farming, 45% was
derived from natural geochemical processes, and 35% from point source inputs.
Less than 1% of the P applied to the landscape in chemical fertilizer and manure
was lost from the watershed in dissolved form.
76:058-010
SOIL NITRATES FOLLOWING FOUR YEARS CONTINUOUS CORN AND AS SURVEYED IN IRRIGATED
FARM FIELDS OF CENTRAL AND EASTERN COLORADO,
Ludwick, A.E., Reuss, J.O., and Langin, E.J.
Colorado State University, Department of Agronomy (Soils), Fort Collins,
Colorado.
Journal of Environmental Quality, Vol. 5, No. 1, p 82-86, January-March 1976.
4 fig, 3 tab, 18 ref.
Descriptors: *Fertilizers, *Nitrogen, *Groundwater, Pollutants, Corn, Irrigation
effects, Colorado, Fertilization, Nutrients, Soil texture, Beans.
High rates of fertilizer N used in many intensive farm management systems have
been cited as a potential pollution hazard to surface and ground waters. The
purpose of this study was to evaluate soil N03(-) accumulations following 4
years continuous corn grown with different nitrogen and irrigation regimes, and
to compare these results to present N03(-) concentrations found in irrigated
farm fields of central.and eastern Colorado. Soil N03(-) content in the 300-cm
sampled profile was significantly influenced by both fertilizer N and irrigation
treatments; the greater accumulations were associated with the two higher
fertilizer N rates and two lower irrigation rates. Nitrate increased linearly
185
-------
in relation to fertilizer N between 67 and 269 kg N/ha and could be described
by two simple regression equations separating the irrigation treatments into
two groups (1-2 and 1-3, low rates; 1-4 and 1-5, high rates). Coefficients of
determination for the two groups were 0.981 and 0.975, respectively.
76:05B-011
NITRATE DYNAMICS IN FALL CREEK, NEW YORK,
Johnson, A.H., Bouldin, D.R., Goyette, E.A., and Hedges, A.M.
Pennsylvania University, Regional Planning Division, Philadelphia, Pennsylvania.
Journal of Environmental Quality, Vol. 5, No. 4, p 386-391, October-December
1976. 5 fig, 3 tab, 11 ref.
Descriptors: *Watersheds (basins), New York, Leaching, Water quality. Farm
wastes, Agriculture.
Nitrate loss from a 330 sq km rural watershed in central New York was monitored
over a 31-month period. Seasonal N03-N patterns were well defined with highest
levels in the winter and lowest levels in the summer resulting from accumulation
of N03-N in the soil profile during the growing season and leaching during the
winter months. Stream water at the outlet of the watershed studied is used as
a source of drinking water for some 20,000 people. Nitrate-N concentrations at
the drinking water intake- currently do not exceed 3 mg/liter. Human activities
affected N03-N levels, with dairying and sewage being the major contributors.
If agriculture is expanded to its maximum acreage, keeping the present ratio
of corn/hay/pasture/people, N03-N levels at the drinking water intake will not
exceed present standards for drinking water.
76:058-012
MOVEMENT OF FERTILIZER AND HERBICIDE THROUGH IRRIGATED SANDS,
Mansell, R.S., Rhoads, F.M., Hammond, L.C., Selim, H.M., and Wheeler, W.B.
Florida University, Department of Soil Science, and Florida University,
Gainesville Institute of Food and Agriuclture, Gainesville, Florida.
Available from the National Technical Information Service, Springfield,
Virginia, and PB-261 505, Price codes: A04 in paper copy, A01 in microfiche.
Florida Water Resources Research Center, Gainesville, Publication No. 38,
September 10, 1976. 50 p, 21 fig, 4 tab, 20 ref, append. OWRT A026-FLAC10).
14-34-0001-6010.
Descriptors: Infiltration, Irrigation, Herbicides, Fertilizers, Kinetics,
Sorption, Soils, Path of pollutants, *Sands, *Florida, Irrigated land, Leaching.
The simultaneous movement of water and selected agrichemicals (.fertilizer nutri-
ents and herbicide) through sandy soils is of particular importance to the effic-
ient use of fertilizers and irrigation water by agricultural crops. Efficient
use of fertilizers and herbicides applied to Florida's sandy soils is desirable
for maintaining optimum growth of plants and for minimizing groundwater
contamination. Laboratory and field experiments as well as mathematical models
were used to study water and solute (potassium and phosphorus nutrients and
2,4-D herbicide) transport in two representative Florida soils: Wauchula sand
and Troup sand. In an irrigated and fertilized corn experiment, grain yields
and efficiency of water use were observed to be mutually related to both the irriga-
tion and the fertilizer application treatments. Leaching of applied nutrients
and irrigation water from the soil "rooting zone" resulted in decreased water
use efficiency in these soils. Mathematical models were developed and used to
simulate transport and chemical-physical reactions for potassium, phosphorus
and 2,4-D herbicide in these soils. Reactions such as adsorption-desorption,
chemical precipitation and immobilization, (fixed) greatly influenced the movement
and thus potential leaching of these solutes through the soil.
76:05B-013
THE POTENTIAL CONTRIBUTION OF FERTILIZERS TO WATER POLLUTION,
Douglas, L.A.
Rutgers-The State University, Department of Soils and Crops, New-Brunswick, New
Jersey.
Available from the National Technical Information Service, Springfield, Virginia,
as PB-259 609, Price codes: A05 in paper copy, A01 in microfiche. Water
186
-------
Resources Research Institute, Rutgers University, Mew Brunswick, New Jersey
Partial Completion Report June 1976. 92 p, 50 fig, 16 tab, 45 ref OWRT A-027-
NJ(6). 14-31-0001-3830.
Descriptors: *Nitrates, *Nitrites, *Ammonia, *Phosphates, *Leaching, *Fertili-
zers, Land use, *New Jersey, *Denitrification, Nitrogen, Nutrients, Water
pollution sources.
Field studies xere undertaken to determine the magnitude of leaching of fertili-
zer N03, NH4 and P04. The effect of N-SERVE on these reactions was observed,
N-SERVE had little effect on leaching because most leaching takes place during
the fall and winter when precipitation exceeds evapotranspiration. No leaching
of NH4 or P04 was observed. The common fertilizer efficiency measure of N in
crop/N applied in fertilizer may be used as an indication of the amount of
fertilizer N that will be leached. Studies of nutrients in streams were under-
taken to relate land use to N03, NH4, and P04 concentrations in surface waters.
Sewage treatment plants and "illegal drains" were major sources of all three
ions. In order of decreasing contribution O£ NO3: urban land contributes more
than cropland which contributes more than woodlands. Urban lands, croplands and
woodlands contribute equal amounts of NH4 and P04 to streams. The "background
level" of PO4 in .central New Jersey streams is many tim"es higher than the 0.01
ppm level often advocated. Although very high concentrations of N03 were found
in the soil solution in the subsoil the concentration of N03 found in streams
was rather low. Denitrification must be an active process in subsoils, and
probably in the groundwater.
76:05B-014
PREDICTING 2,4,5-T MOVEMENT IN SOIL COLUMNS,
O'Connor, G.A., van Genuchten, M. Th.; and Wierenga, P.J.
New Mexico State University, Las Cruces, New Mexico.
Journal of Environmental Quality, Vol. 5, No. 4, p 375-378, October-December
1976. 8 fig, 1 tab, 9 ref.
Descriptors: *Model studies, *Effluents, *Tritium, 2,4,5-T, Soils, Soil investi-
gations, Adsorption, Pesticides, Herbicides.
A solute model developed by van Genuchten and Wierenga was used to calculate
2,4,5-T effluent data from soil columns. The model had been previously shown to
adequately predict effluent data given model parameters curve fit to a portion of
the effluent curve. The present work shows that 2,4,5-T .effluent curves may be
adequately predicted without prior knowledge of the effluent curves for a parti-
cular soil column given: (i) model parameters derived from 2,4,5-T effluent
curves for other soil columns, or (ii) model parameters obtained from tritium
effluent curves for the same columns. The data suggest that once the physical
model parameters have been characterized for a soil, reasonable predictions of
2,4,5-T (and perhaps other solutes) transport can be made given the adsorption
coefficient for the solute.
76:05B-015
DISTRIBUTION OF PLUTONIUM IN TRINITY SOILS AFTER 28 YEARS,
Nyhan, J.W., Miera, F.R. Jr., and Neher, R.E.
Los Alamos Science Laboratory, Soil Science, Los Alamos, New Mexico.
Journal of Environmental Quality, Vol. 5, No. 4, p 431-437, October-December
1976. 6 fig, 4 tab, 22 ref.
Descriptors: Soils, Soil investigations, Nuclear wastes. Nuclear explosions.
Sampling, Soil horizons. Soil profiles, Carbonates.
The soils of four intensive study areas located along the fallout pathway of
Trinity, the first nuclear detonation, were sampled to determine soil plutonium
concentrations as a function of distance from Ground Zero and soil depth. About
half of the 239,240Pu in Trinity soils was found at the 5-20 cm depth in 1973
compared to total plutonium inventories found only in the upper 5 cm of soil
about 20 years ago. Soil plutonium concentrations of samples collected at the
same depth of each study area generally exhibited coefficients of variation > 1.2.
Maximum penetration depths of 239,240Pu into Trinity Site soils were related to
the presence of subsoil horizons containing carbonate accumulations and the maxi-
mum extent of rainwater penetration into these soil profiles.
187
-------
76:05B-016
SALT AND WATER BALANCE IN IMPERIAL VALLEY, CALIFORNIA,
Kaddah, M.T., and Rhoades, J.D.
Imperial Valley Conservation Research Center, Brawley, California.
Soil Science Society of America Journal, Vol. 40, No. 1, p 93-100, January-
February 1976. 4 fig, 2 tab, 13 ref.
Descriptors: *Salinity, *Salt balance, *Salts, Soil salinity, Water salinity,
Root zone. Ground water, Surface runoff. Effluents, Water quality, California.
Salt balance of the Imperial Valley has been determined annually since 1943 by
the Imperial Irrigation District. Salinity trends in the valley are assessed
from biweekly measurements of the volume, V, and concentration, C, of influent
inf.w, and effluent, eff.w, waters. This paper summarized the SB (Salt Balance)
data, evaluates their significance, and suggests approaches for assessing salinity
trends in the soils of the valley. The SB data reflected the cropping and water
use patterns in the valley. However, the data were insufficient to distinguish
origin of water and salt in effluent water or to provide information about changes
in root zone salinity. In 1973 total evapotranspiration (ET) by crops in the
valley was estimated to be 229 multiplied by 1,000 ha-m, equivalent to 70% of the
water delivered to the farmers. Deductions as to Cl(-) composition of influent
and effluent during 1973 suggest that the Cl(-) load in the effluent water was
contributed as follows: 54.7% from ground water, 35.0% from root zone drainage
water, and 10.3% from tail water (runoff).
76:05B-017
MOVEMENT OF CARBARYL THROUGH CANGAREE SOIL INTO GROUND WATER,
LaFleur, K.S.
Clemson University, Department of Agronomy and Soils, Clemson, South Carolina.
Journal of Environmental Quality, Vol. 5, No. 1, p 91-92, January-March 1976.
1 fig, 3 tab, 6 ref.
Descriptors: Soil profiles, Ground water, Pollutants, Soil investigations.
Carbaryl was applied to a Congaree sandy loam fieldplot containing a shallow
(about -1.1 m) water table. Movement and loss in the soil profile, and accumu-
lation in underlying ground water were monitored for 16 months. Rainfall during
this time was 182 cm (3.5 pore volumes based on the upper 1 m of soil). The upper
1 m contained about 6% of the applied carbaryl after 16 months. No carbaryl was
found in the 0-20 cm layer after the 4th month. Loss of carbaryl with time in
the upper 1 m was concentration-dependent. Time to half-concentration within the
upper 1 m was < 1 month. Carbaryl appeared in the underlying ground water within
2 months after soil application and persisted through the 8th month. Maximum
ground water concentration, about 0.3 micromol/liter, occurred at the end of the
second month.
76:058-018
LOSSES OF NITROGEN IN SURFACE RUNOFF IN THE BLACKLAND PRAIRIE OF TEXAS,
Kissel, D.E., Richardson, C.W., and Burnett, E.
Texas A and M University, Texas Agricultural Experiment Station, College Station,
Texas.
Journal of Environmental Quality, Vol. 5, No. 3, p 288-293, July-September 1976.
1 fig, 4 tab, 16 ref.
Descriptors: *Clays, *Nitrogen, *Texas, Fertilization, Watersheds (basins),
Runoff, Pollution, Surface runoff.
The objective of this study was to determine N03(-)-N and total N losses in
surface runoff from Houston Black clay, a swelling clay soil with a relatively
low infiltration rate. The study was carried out on duplicate 4-ha watersheds
cropped to a rotation of grain sorghum, cotton, and oats, all fertilized at
recommended rates of N application. The loss of N03(-)-N varied considerably
during the study, depending on events before each runoff-producing storm. Concen-
trations of N03(-)-N were usually highest just after fertilizer application when
the soil was near field capacity and lowest when large amounts of water infiltra-
ted into dry soil immediately before runoff. During runoff-producing storms
just after fertilizer application, the concentrations were lowest in the initial
runoff and highest near the end of the runoff event. To compute NO3(-)-N losses
188
-------
with reasonable accuracy on these soils, the shape of the entire N03(-)-N con-
centration curve needed to be well defined. In general, the results of this
study indicate that a small and probably insignificant amount of N is lost to
surface waters when crops are fertilized at recommended N rates in the Texas
Blackland Prairie. For the entire 5-year study, the mean concentration of
N03(-)-N in runoff was 2.9 and 2.3 ppm N03(-)-N for the duplicate watersheds.
The mean total loss of N03(-)-N was 3.2 kg ha (-1) year(-l). Losses of sediment
associated N were about 5 kg N ha(-l) year(-l).
76:058-019
THE IMPACT OP FERTILIZER USE AND CROP MANAGEMENT ON NITROGEN CONTENT OF SUBSURFACE
WATER DRAINING FORM UPLAND AGRICULTURAL WATERSHEDS,
Chichester, F.W.
United States Department of Agriculture, Agricultural Research Service, Temple,
Texas.
Journal of Environmental Quality, Vol. 5, No. 4, p 413-416, October-December
1976. 2 fig, 3 tab, 13 ref.
Descriptors:*Nitrogen, *Fertilizers, Fertilization, Agricultural Watersheds,
Ohio, Sampling, Land management. Water quality, Deep percolation, Groundwater,
Soils, Spring waters, Hydrogeology. '
Spring flow and stream base flow sites were sampled weekly on and adjacent to
a 123-ha agricultural watershed in the Allegheny-Cumberland Plateau physiographic
region of east-central Ohio. Nitrogen content of samples was used to determine
the influence of various N fertilizer and crop management practices on the qual-
ity of subsurface water draining from defined contributing areas. Measured
nitrogen contents of spring flow were related to fertilizer N regime of the dif-
ferent agricultural practices investigated. Changes in land management on the
area contributing to spring flow were reflected in changes in nitrogen content
of water from that spring. The amount of nitrogen which was transported into
the stream channel was directly related to seasonal variation in subsurface flow
rate in two ways. First, the concentration of N in spring flow increased with
an increase in the amount of water percolating through the overlying soil and
shale. Second, the extent to which downstream quality was affected, i.e., the
distance from the area of fertilizer application at which an increase in nitrogen
content could be detected, also increased with the volume of flow from the
springs.
76:058-020
CHEMICAL DISTRIBUTION AND GASEOUS EVOLUTION OF ARSENIC-74 ADDED TO SOILS AS
DSMA-(74)AS, -
Akins, M.B., and Lewis, R.J.
Tennessee University, Department of Plant and Soil Science, Tennessee Agricultural
Experiment Station, Knoxville, Tennessee.
Soil Science Society of America Journal, Vol. 40, No. 5, p 655-658, September-
October 1976. 5 tab, 17 ref.
Descriptors: Arsenic compounds, Organic matter, Soil moistures, Soils, Soil
investigations.
Gaseous evolution of (74)As from a soil treated with arsenic-74 labeled disodium
methanearsenate at 100 g/g was a function of organic matter addition and moisture
conditions. Loss of (74)As was greatest from soils that received an exogenous
carbon source and were maintained under wet conditions. Arsenic-74 sorbed by
soils of pH 4,6, and 8 was fractionated by a differential dissolution precedure
commonly used for phosphorus. Iron arsenate (soluble in O.lN NaOH) was the most
abundant form followed by aluminum arsenate (soluble in 0.5N NH4F). The soils
generally contained more aluminum arsenate at pH 4 than at pH 6 or 8. Calcium
arsenate fractions (soluble in 0.5N N2S04) were usually higher at pH 6 and 8
than at pH 4. Water-soluble forms and nonextractable forms were inversely
proportional to each other.
189
-------
76:05B-021
DISSOLVED NUTRIENT LOSSES IN STORM RUNOFF FROM FIVE SOUTHERN PINE WATERSHEDS,
Schreiber, J.D., Duffy, P.O., and McClurkin, D.C.
Agricultural Research Service, Sedimentation Research Laboratory, Oxford,
Mississippi.
Journal of Environmental Qualtiy, Vol. 5, No. 2, p 201-205, 2 fig, 6 tab,
21 ref.
(See 76:02E-001)
76:056-022
EFFECT OF ATMOSPHERIC STABILITY ON WATER TEMPERATURE PREDICTIONS FOR A THERMALLY
LOADED STREAM,
DeWalle, D.R.
Pennsylvania State University, School of Forest, University Park, Pennsylvania.
Water Resources Research, Vol. 12, No. 2, p 239-244, April 1976. 3 fig, 2 tab,
19 ref. OWRT C-4199(No. 9032)(2).
Descriptors: *Model studies, *Energy budget, *Water temperature, *Heat transfer,
*Discharge(Water), Air-water interfaces, Air temperature, Humidity, Wind velo-
city, Radiation, Equations, Pennsylvania, Atmosphere, *Thermal pollution.
A steady state one-dimensional energy budget equation was numerically integrated
to predict water temperatures in a 5.45-km-long thermally loaded stream reach
for 131 five- or six-hour periods. Downstream water temperature prediction
errors (measured minus predicted) using Jobson's Lake Hefner evaporation equa-
tion averaged -2.11 C and were well correlated (R2 = 46%) with an index to
atmospheric stability. Use of a modified form of Shulyakovskiy's evaporation
equation, which includes a term for evaporation by free convection, significant-
ly reduced the average prediction error to 0.89 C and eliminated the effects of
atmospheric stability (R2 less than 1%). Correction of wind velocity data for
the velocity of the air relative to the stream velocity also reduced prediction
errors.
76:058-023
PULSED DISPERSION OF TRACE CHEMICAL CONCENTRATIONS IN A SATURATED SORBING
POROUS MEDIUM,
Lindstrom, F.T.
Oregon State University, Department of Statistics, and Department of Mathematics,
Corvallis, Oregon.
Water Resources Research, Vol. 12, No. 2, p 229-238, April 1976. 5 fig, 22 ref.
PHS ES-00040.
Descriptors: *Dispersion, *Mathematical models, *Distribution patterns. Satur-
ated flow, Sorption, Porous media, Equations, Soil water. Theoretical analysis,
Graphical analysis. Computers, Water chemistry. Trace elements. Mass transfer,
Laplaces equation, *Path of pollutants.
A rather simple, yet complete, mathematical model for the pulsed dispersion of
trace chemical concentrations in a water-saturated sorbing porous medium was
stated, and the resulting integrodifferential equation of transport was solved
via Laplace transform methods. A typical example of a soil water dispersion
system was discussed with the aid of free and sorbed phase concentration distri-
bution curves.
76:05B-024
NUMERICAL SIMULATION OF WASTE MOVEMENT IN STEADY GROUNDWATER FLOW SYSTEMS,
Pickens, J.F., and Lennox, W.C.
Waterloo University, Department of Earth'Sciences, Ontario, Canada.
Water Resources Research, Vol. 12, No. 2, p 171-180, April 1976. 10 fig,
1 tab, 24 ref.
Descriptors: *Model studies, *Groundwater movement, *Underground waste
disposal, Groundwater, Waste disposal, Water pollution. Water pollution sources,
*Path of pollutants, Mathematical models. Finite element analysis, Analytical
techniques. Wastes, Waste disposal wells, Flow, Flow system. Water table,
Infiltration.
190
-------
The finite element method based on a Galerkin technique was used to formulate
the problem of simulating the two-dimensional transient movement of conserva-
tive or. nonconservative wastes in a steady state saturated groundwater flow
system. The convection-dispersion equation was solved in two ways: in the con-
ventional Cartesian coordinate system and in a transformed coordinate system
equivalent to the orthogonal curvilinear coordinate system of streamlines and
normals to those lines. The two formulations produced identical results A
sensitivity analysis on the dispersion parameter "dispersivity" was performed,
establishing its importance in convection-dispersion problems. Examples involv-
ing the movement of nonconservative .contaminants described by distribution
coefficients and samples with variable tribution coefficients and examples with
variable input concentration were also given. The model can be applied to
environmental problems related to groundwater contamination from waste disposal
sites.
76-.05B-025
A FINITE ELEMENT MODEL OF CONTAMINANT' MOVEMENT IN GROUNDWATER,
Cabrera, G. and Marino, M.A.
Chile University, Centre de Recursos Hidraulicos, Santiago, Chile.
Water Resources Bulletin, Vol. 12, No. 2, p 317-335, April 1976. 9 fig, 17 ref.
Descriptors: *Model studies, Wastes, *Groundwater movement, Mathematical models,
Computer models, *Finite element analysis. Pollutants, *Path of pollutants,
Groundwater, Aquifers, Streams, Recharge, Groundwater recharge, Infiltration,
Flow, Surface-groundwater relationships, Subsurface flow. Subsurface waters.
Transient, two-dimensional solutions were developed which describe the movement
and distribution of a conservative substance in a stream-aquifer system. The
solutions were obtained by solving sequentially the groundwater flow and mass
transport equations. A variational approach in conjunction with the finite
element method was used to solve the groundwater flow equation. Galerkin's
approach coupled with the finite element method was used to solve the mass
transport equation. Linear approximated triangular elements and a centered
scheme of numerical integration were employed to calculate the hydraulic head
distribution and the concentration of solute in the flow region. The linear
approximation used to define the concentration function within each element is
not appropriate for cases involving steep concentration gradients. For such
cases, higher order approximations are necessary to assure the continuity of
gradients across interelemental boundaries. Numerical examples that illustrate
the applicability of the model were presented.
76:05B-026
AN ANALYSIS OF THE NUMERICAL SOLUTION OF THE TRANSPORT EQUATION,
Gray, W.G., and Pinder, G.F.
Princeton University, Department of Civil Engineering, Princeton, New Jersey.
Water Resources Research, Vol. 12, No. 3, p 547-555, June 1976. 8 fig, 1 tab,
5 ref. NSF-AER74-01765.
Descriptors: *Mass transfer, *Dispersion, *Finite element analysis, *Numerical
analysis, *Fourier analysis, Waves (Water), Convection, Computers, Equations,
Mathemeical studies, *Path of pollutants.
The relative merits of numerical procedures used for the solution of the convec-
tive dispersive mass transport equation were examined in terms of frontal smear-
ing and concentration overshoot. The testing for assessing the relative accura-
cy of some selected numerical procedures was based on a Fourier series represen-
tation of the solution to the governing equation and its discretized counterpart
Through a comparative examination of the analytically and numerically computed
amplitude and speed of the Fourier components, the dispersive and dissipative
properties of a numerical scheme were easily analyzed. The analysis indicated
that the commonly observed phenomenon of overshoot of a concentration pulse was
due to the inability of the numerical schemes to propagage the small wavelengths
which are important to the description of the front. The numerical smearing of
a sharp front was due to dissipation of these small wavelengths. The finite
element method was found to be superior to finite difference methods for solu-
tion of the convective-di'spersive equation.
191
-------
76:058-027
ANALYTICAL THREE-DIMENSIONAL TRANSIENT MODELING OF EFFLUENT DISCHARGES,
Yeh, G.T., and Tsai, Y.J.
Stone and Webster Engineering Corporation, Boston, Massachusetts.
Water Resources Research, Vol. 12, No. 3, p 533-540, June 1976. 10 fig,
19 ref.
Descriptors: *Unsteady flow, *Dye releases, *Dye concentration, *Effluents,
*Analytical techniques, *Turbulent flow, *Hudson River, *Mathematical models,
Thermal pollution, Diffusion, Buoyancy, Density currents, Tidal waters,
Equations, Pollutant identification, *Path of pollutants.
A transient, three-dimensional turbulent diffusion equation describing the con-
centration distribution of a substance or heat in a time-dependent flow field
was solved analytically. Two models were considered: one treated both the
depth and the width of a water body as being finite, while the other dealt
with finite depth but with infinite width. In the search for solutions, the
method of Green's function was utilized to the optimum advantage. The solutions
were developed for cases in which the velocity field can be described as any
integratable function of time. For practical applications, the velocity was
assumed to be the sum of a constant and a harmonic component. There were no
limitations on the type of source conditions. Results were compared with field
measurements and showed the models to be capable of simulating the dye distribu-
tion in tidal water bodies. The models should provide the engineering community
with a quick and easy way of predicting the distribution of effluent discharges.
They should obviate the need of using tedious and time-consuming numerical
models, as occasions often arise in which such complicated models may not be
warranted.
76:05B-028
DESCRIBING VARIANCE WITH A SIMPLE WATER QUALITY MODEL AND HYPOTHETICAL
SAMPLING PROGRAMS,
Moore, S.F., Dandy, G.C., and DeLucia, R.J.
Massachusetts Institute of Technology, Department of Civil Engineering,
Cambridge, Massachusetts.
Water Resources Research, Vol. 12, No. 4, p 795-804, August 1976. 7 fig,
2 tab, 18 ref.
Descriptors: *Water quality control, *Sampling, *Decision making, Evaluation,
Time, History, Data collections, Estimating, Mathematical models, Simulation
analysis. Costs, Impoundments, Eutrophication, Equations, Systems analysis,
*Risks.
An explicit treatment of the uncertainty in the state of water quality in a
body of water can provide a quantitative basis for sampling decisions. Filter-
ing theory, an extension of Bayesian analysis to dynamic systems, is used to
obtain an algorithm which describes the time history of variance (uncertainty)
in estimates of water quality parameters. Uncertainties arising from measure-
ment errors, incompleteness of data, and random fluctuations exhibited by natural
phenomena are taken into account. Sampling design capabilities are illustrated
in an evaluation of sampling frequencies for the National Eutrophication Survey.
The adequacy of any sampling program is dependent'on the available prior data
and on the value associate with reductions in uncertainty.
76:05B-029
OPTIMAL ESTIMATION OF DO, BOD, AND STREAM PARAMETERS USING A DYNAMIC DISCRETE
TIME MODEL,
Koivo, A.J., and Phillips, G.
Purdue University, Department of Electrical Engineering, Lafayette, Indiana.
Water Resources Research, Vol. 12, No. 4, p 705-711, August 1976. 9 fig,
10 ref.
Descriptors: *Path of pollutants, *Model studies, *0ptimization, *Biochemica'l
oxygen demand, *Dissolved oxygen, *Streams, *Mathematical models, Computer-
models, Dynamic programming, Organic matter, Water quality, Water pollution,
Pollutants, Reaeration, Self-purification, Waste assimilative capacity,
Equations, Mathematical studies.
192
-------
A modified Streeter-Phelps equation was used as the starting equation to obtain
a discrete time mathematical representation which represents a model for the
biological oxygen demand and the dissolved oxygen concentrations in a polluted
stream. The unknown parameters to be estimated were treated as state variables
in order to compute their numerical values from noise-corrupted measurements
An optimal estimator was constructed for the estimation of the unknown parameters.
The optimization scheme can be implemented in a small computer. The approach
was illustrated by a numerical example.
76:058-030
SIMILARITY OF THE MEAN MOTION OF FLUID PARTICLES DISPERSING IN A NATURAL CHANNEL
Day, T.J., and Wood, I.R.
Geological Survey of Canada, Ottawa, Ontario, Canada.
Water Resources Research, Vol. 12, No. 4, p 655-666, August 1976 13 ficr
3 tab, 22 ref. y'
Descriptors: *Dispersion, *Flow, *Turbulence, *Channel morphology, *Hydrologic
data. Velocity, Methodology, Tracers, Distribution patterns, Statistical methods.
The longitudinal dispersion in natural river channels was shown to exhibit the
characteristics,constant velocity ratios, and similarity in the distribution
of physical dimensions of a self-similar process. Although the kinematic rela-
tions and the structure of the turbulent field were sensitive to the nature of
the flow boundaries and the geometry of the channel, similarity was maintained
in flows in a wide range of steep gravel and boulder bed channels. A simple
method was developed for predicting the longitudinal pattern of dispersion. It
contained three basin hydraulic parameters which could be determined by a field
experiment. Data on steep channels and distances up to 1000 channel widths from
the dump point were used in developing the method. Though these data were rather
limited in scope, the results suggested that the general method may be applica-
ble to streams with a range of characteristics.
76:056-031
MODELING OF UNSTEADY TEMPERATURE DISTRIBUTION IN RIVERS WITH THERMAL DISCHARGES,
Hills, R.G., and Viskanta, R.
Purdue University, School of Mechanical Engineering, and Heat Transfer Labora-
tory, Lafayette, Indiana.
Water Resources Research, Vol. 12, No. 4, -p 712-722, August 1976. 20 fig,
29 ref.
Descriptors: *Heated water, *Thermal stratification. Analytical techniques,
*Turbulent flow, *Mixing, Water temperature, Channel flow, Heat transfer,
Radiation, Numerical analysis. Equations, Rivers, *Thermal pollution.
Unsteady temperature distribution was analyzed in a wide channel simulating a
river. The effects of thermal discharges, meteorological conditions, solar
and atmospheric radiation, and channel parameters on the thermal structure of
a river were analyzed and discussed by utilizing an analytical model for the
unsteady three-dimensional temperature distribution in the far field of a
thermally stratified channel. The conservation of energy equation for turbulent
flow was solved numerically with an alternating direction implicit finite
difference scheme. The effects of thermal start-up, discharge temperature leveL
discharge location, river flow velocity, and other factors were investigated.
The results showed that the greater the temperature excess above the ambient at
the discharge, the greater downstream distance is needed to reach a fully mixed
condition because of the suppressive effect of stratification on the turbulent
mixing. The greater surface temperatures associated with thermally stratified
flow resulted in increased heat dissipation and water evaporation from the
surface.
NITRATE AND CHLORIDE POLLUTION OF AQUIFERS: A REGIONAL STUDY WITH THE AID OF
A SINGLE-CELL MODEL,
Mercado, A.
Tahal-Water Planning for Israel, Limited, Tel-Aviv, Israel.
Water Resources Research, Vol. 12, No. 4, p 731-747, August 1976. 15 fig,
193
-------
6 tab, 7 ref.
Descriptors: *Nitrates, *Chlorides, *Water pollution, *Aquifers, *Mathematical
models, Water pollution sources, Hydrologic properties, Zone of aeration, Water
wells, Water table, Biochemistry, Groundwater, Tracers, Forecasting, Monte Carlo
method, Probability, Statistical models, Tertiary treatment, Groundwater
recharge, Equations.
A single-cell model was used -to study the regional chloride and nitrate pollu-
tion patterns in part fo the coastal aquifer of Israel. The model integrated
pollution sources on the land surface, hydrologic parameters of the aquifer and
the unsaturated zone, and variations of chloride and nitrate concentration dist-
ribution in pumping wells. Complicated hydrologic and biochemical processed in
the unsaturated zone were simplified and represented by two basic parameters:
(1) transit time from land surface to the aquifer, and (2) nitrogen losses in
the soil. It was shown that linear relationships exist between nitrogen quanti-
ties released on the surface and the quantities reaching the water table. The
calibration of the model enabled its use for prediction purposes. The Monte
Carlo technique was introduced to determine the range of predicted average
groundwater concentrations as a function of time. The forecasts presented call
for urgent protection measures in order to meet drinking water standards for
maximum nitrate concentrations. Thirteen alternative protection measures were
examined and then compared to predictions based on present nitrogen loads and
hydrologic regime. The exchange relationships between these measures were
derived, and it was suggested that they can be used later for evaluating econo-
mic criteria for protecting groundwater quality -
76-.05B-033
DISPERSION OF WATER POLLUTANTS IN A TURBULENT SHEAR FLOW,
Yeh, G.T., and Tsai, Y-J.
Stone and Webster Engineering Corporation, Boston, Massachusetts.
Water Resources Research, Vol. 12, No. 6, p 1265-1270, December 1976. 4 fig,
14 ref.
Descriptors: *Dispersion, *Pollutants, *Turbulent flow, *Model studies, Mathema-
tical models, Water quality, Rivers, Streams, Velocity, Diffusivity, Flow,
Streamflow, Analytical techniques, Water pollution sources, *Path of pollutants,
A steady-state, two dimensional turbulent diffusion equation discribing the
concentration distribution of a substance from a line source in a shear flow
field was solved analytically. A similar formulation may be developed for any
other kinds of sources. In the study, the velocity and eddy diffusivity were
assumed to be variables given by the power law approximations, and the depth of
the water body was assumed finite, with no-flux boundary conditions applied at
the water surface and bottom. This represents a first step toward analytical
water quality modeling, which realistically includes the effects of both the
finiteness in water depth and the nonhomogeneity in velocity and diffusivity.
Results from the present model were compared with those obtained from the fin-
ite depth constant coefficient model and from the infinite depth constant
coefficient model. They showed significant and realistic differences in the
prediction of concentration patterns. The effects of nonhomogeneous velocity
and diffusivity are cancelled out by the effect of boundary reflection far away
from the source.
76:05B-034
COMPUTER SIMULATION OF PHOSPHORUS MOVEMENT THROUGH SOILS,
Barter, R.D., and Foster, B.B.
New Hampshire University, Institute of Natural and Environmental Resources,
Durham, New Hampshire.
Soil Science Society of America Journal, Vol. 40, No. 2, p 239-242, March-April
1976. 4 fig, 1 tab, 9 ref.
Descriptors: Computer models, Model studies, Phosphorus, Soil investigations,
Mathematical models, Waste water, Nutrients, Fertilization.
Although the movement of P through soil can be described by mathematical models,
this approach has certain limitations in practical application, particularly :
194
-------
™? used for waste water renovation. TO circumvent the limitations of
mathematical modeling, empirical adsorption equations can be obtained and
utilized in computer simulation of phosphorus movement, in this way the
renovation lifetime of a soil can be estimated. This approach is not limited
to P, and can be used for any potential ground-water contaminate, whether
inorganic or organic.
76:058-035
AGRICULTURAL RUNOFF, A BIBLIOGRAPHY, VOLUME 2
Office of Water Research and Technology,
Washington, D.C.
Water Resources Scientific Information Center, Report OWRT/WRSIC 76-203
July 1976, 286 p.
Descriptors: *Agricultural runoff, *Bibliographies, *Farm wastes, *Feed lots,
Waste disposal,. Waste treatment. Water pollution sources, Water pollution control.
Runoff, Path of pollutants.
This report, containing 187 abstracts, is another in a series of planned
bibliographies in water resources produced from the information base comprising
SELECTED WATER RESOURCES ABSTRACTS (SWRA) . At the time of search for this
bibliography, the data base had 95,781 abstracts covering SWRA through April 15,
1976 (Volume 9, Number 8). Author and subject indexes are included. The first
volume (see W72-05840) was issued in January 1972 and covered the material
announced in SWRA from October 1968 through December 1971. This volume covers
the period from January 1972 through April 1976.
76:05B-036
SUBSURFACE BRINE DISPOSAL - BE REASONABLE,
Fryberger, J.S.
Engineering Enterprises, Inc., Norman, Oklahoma.
Ground Water, Vol. 14, No. 3, p 150-156, May-June 1976. 5 fig, 11 ref.
Descriptors: *Brine disposal, *Groundwater, *Hydrogeology, *0klahoma, Oil wells,
Oil wastes. Injection wells, Brines, Waste disposal, Wastes, Pollutants, Aquifers,
Piezometry, Potentiometric level. Geology, Legal aspects, Oil industry,
Agriculture, Irrigation.
A classic battle between landowners desireing to protect their fresh groundwater
from possution and oil companies needing a disposal zone for injection of oil-
field brines developed in Texas County, Oklahoma. Initial studies showed that
the disposal zone (Glorieta Formation) was in placed only 500 feet below the
bottom of the fresh-water aquifer (Ogallala Formation). Solution/collapse
features in the intervening formations plus numerous poorly plugged wells and
exploration holes provided potential avenues of brine migration. The potential
for pollution appeared very real. The landowners not only wanted to halt
construction of new brine disposal wells, but also wanted all 33 existing
disposal wells abandoned and plugged. Tempers flared and intermittent litiga-
tion continued for over two years. A more complete hydrogeologic analysis led
to the following observations: (1) the potentiometric surface in the Glorieta
is 100 to 400 feet below the water table in the Ogallala in areas where brine
disposal is taking place; and (2) the transmissivities of the Glorieta and
disposal rates are such that even pressure gradients around disposal wells
are below the water level in the Ogallala. These hydrologic facts led to the
conclusion that, even with a perfectly open conduit connecting the two forma-
tions, migration of disposal brine from the Glorieta into the fresh-water
Ogallala would be impossible in the critical area because of pressure relation-
ships .
76:058-037
PREDICTION OF FUTURE NITRATE CONCENTRATIONS IN GROUND WATER,
Young, C.P., Oakes, D.B.^^and Wilkinson, W.E.
Water Res'earch Centre, " Medmehham Laboratory, Marlow (England).
Ground Water, Vol. 14, No. 6, p 426-438, November-December 1976. 20 fig, 3 tab,
29 ref.
195
-------
Descriptors: *Nitrates, *Groundwater, *Forecasting, Surveys, On-site
investigations, Model studies, Mathematical models, Aquifers, Foreign countries,
Sandstones, Foreign projects, Nitrogen, Chlorides, Tritium, Fertilizers, Wells,
Water wells, Land use, Effects, Agriculture, Water pollution. Pollutants.
Over the last few years, rises in the nitrate content of groundwater from wells
and springs in the principal aquifers of the United Kingdom have been observed.
In a number of cases, the concentrations have exceeded the WHO lower recommended
limit. In order to determine the reason for the rise, to assess whether it will
continue, and to ascertain the eventual nitrate levels, the Water Research Centre
undertook an extensive program of drilling and sampling on the Chalk and Bunter
Sandstone. By August 1976, 22 sites had been examined. This work established
that high nitrate concentrations (peaks up to 60 mg/1 N03-N have been observed)
are present in the unsaturated aquifers at fertilized arable/ley sites. At
unfertilized grassland sites, nitrate concentrations are low (less than 4 mg/1
N03-N), and they are below fertilized established grassland values, which are
in the intermediate range. At one farm site near Winchester, models to predict
the rate of movement of nitrate through the unsaturated and saturated Chalk
were developed. These models suggest that the nitrate levels at this site will
remain at an essentially constant value of about 4 mg/1 N03~N until the late
1970's, when they will rise progressively to about 14 mg/1 NO^-N. The models
were checked against tritium data, and the approach is now being extended to
other sites.
76:05B-038
WASTEWATERS IN THE VADOSE ZONE OF ARID REGIONS: GEOCHEMICAL INTERACTIONS,
Runnells, D.D.
Colorado University, Department of Geological Sciences, Boulder, Colorado.
Ground Water, Vol. 14, No. 6, p 374-385, November-December 1976. 3 fig, 3 tab,
33 ref.
Descriptors: *Waste water disposal, *Arid lands, *Vadose water, *New Mexico,
Geochemistry, Chemical reactions, Leachate, Waste water treatment, Waste
dilution, Hydrogen ion concentration, Chemical precipitation. Hydrolysis,
Oxidation, Reduction (Chemical), Filtration, Membrane processes, Sorption.
Because of increasingly stringent laws governing discharge of fluid wastes to
surface waters, the alternative of discharge to the subsurface has become
attractive. The physical-chemical processes that prevail in the subsurface are
not well understood, but they are clearly not identical to processes of
purification in surface waters. Eleven physical-chemical processes can be
identified as having potential value for purifying wastes discharged to the
subsurface, as follows: dilution, buffering of pH, precipitation by reaction,
hydrolysis oxidation or reduction, filtration, volatilization, biological
assimilation, radioactive decay, membrane filtration, and sorption. Discharge
to the vadose zone may be a safe means of disposal of wastes in arid regions.
But it is necessary to carefully test the suitability of a particular site for
a particular waste. Regulations governing subsurface discharge should take
into account the physical-chemical processes that may, act to purify the waste
fluids. In one set of experiments, a soil from Sulfur Springs, New Mexico, was
capable of removing large quantities of dissolved molybdenum and copper from a
synthetic mill water, and the soil was able to quantitatively retain the copper
during subsequent leaching by fresh and metal-free mill waters.
76:05B-039
MONITORING CYCLIC FLUCTUATIONS IN GROUND-WATER QUALITY,
Pettyjohn, W. A.
Ohio State University, Department of Geology and Mineralogy, Columbus, Ohio.
Ground Water, Vol. 14, No. 6, p 472-480, November-December 1976. 9 fig, 13 ref
Descriptors: *Water quality, *Groundwater, *Groundwater recharge, *Water
pollution. Monitoring, Sampling, Wells, Water wells, Path of pollutants,
Chlorides, Brines, Oil fields. Rainfall, Precipitation (Atmospheric), Aquifers,
Pollution, Fluctuations, Pollutants.
The chemical quality of water in many shallow and surficial aquifers exhibits
cyclic fluctuations. These fluctuations are caused by the intermittent flushing
196
-------
of contaminants into the ground during recharge events. The contaminants may be
natural or reflect man's activities, particularly waste disposal schemes. Over
the past 12 years, an oil field, brine-contaminated aquifer in central Ohio has
been monitored. Data from three closely spaced wells tapping selected parts of
the aquifer indicated that brine is flushed into the ground during recharge
events, and that each contaminated mass maintains much of its integrity as it
sinks to the bottom of the aquifer and then migrates laterally to the adjacent
river. The most concentrated mass that covers the largest area infiltrates during
the spring recharge period, but less concentrated and smaller masses may occur
any time rainfall is sufficient to overcome the soil moisture deficiency.
Because of the cyclic nature of recontamination events, care and common sense
must be exercised in the extrapolation of quality data, particularly in regard
to estimation of contaminant flushing rates.
76:058-040
NONPOINT SOURCE POLLUTION FROM AGRICULTURAL RUNOFF,
Haith, D.A., and J.V. Dougherty
New York State College of Agriculture and Life Sciences, Department of Agri-
cultural Engineering, Ithaca, New York.
Journal of the Environmental Engineering Division, American Society of Civil
Engineers, Vol. 102, No. EE5, Proceedings Paper 12481, p 1055-1069, October 1976.
1 fig, 7 tab, 39 ref, 2 append. OWRT B-030-NY(3).
Descriptors: *Water pollution sources, *Water quality, *Agricultural runoff,
*New York, Nitrogen, Phosphorus, Water pollution. Model studies, Watersheds
(Basins), Nutrients, Storm runoff, Surface waters, Estimating, Forecasting,
Agriculture, Agricultural watersheds, Farm wastes.
An operational procedure was developed which is suitable for estimating nonpoint
source water pollution due to runoff from agricultural land and is sensitive to
regional variations in weather, soils, and crop management. Runoff was estimated
using the Soil Conservation Service's semi-empirical runoff equation. Although
not presently applicable to snowmelt runoff,, the procedure could be extended to
winter runoff by use of suitable estimating methods. Nitrogen and phosphorus in
agricultural runoff were estimated for a five-watershed area totalling 578 sq km
in Broome and Tioga Counties, New York, for the years 1971 and 1972. Comparison
was made with two other estimates which were obtained using areal loading factors
(losses of nutrients per unit area). Although the three different estimates were
of comparable orders of magnitude, the loading factor estimates were not sensi-
tive to the soils, weather, or crop distributions of the study region and may
overestimate losses of nitrogen in agricultural runoff.
76:056-041
GEOELECTRIC SOUNDING FOR DELINEATING GROUND-WATER CONTAMINATION,
Kelley, W.E.
Rhode Island University, Department of Civil and Environmental Engineering,
Kingston, Rhode Island.
Ground Water, Vol.- 14, No. 1, p 6-10, January-February 1976. 7 fig, 12 ref.
Descriptors: *Resistivity, *Water pollution, *Landfills, *Rhode Island,
Conductivity, Groundwater, Glacial aquifers, Water quality, Path of pollutants,
Monitoring.
A resistivity survey was made in the vicinity of a landfill in a glacial aquifer
to determine the extent of groundwater contamination. An examination of the
sounding curves and logs of nearby test borings suggested a three-layer
geoelectric model for studying water quality variations. The thicknesses and
the resistivities of the upper two layers were fixed. Differences in apparent
resistivity were assumed to be due only to differences in specific conductance
of groundwater in the saturated zone (third-layer resistivities). Apparent
resistivities at the largest probe spacing, 102 feet, were then computed for a
range of assumed third-layer resistivities. Specific conductances corresponding
to third-layer resistivities were then computed using an assumed formation
factor of 4.5. A relation between apparent resistivity at the 102-ft spacing
and specific conductance was developed for converting apparent resistivities to
specific conductances. Quadratic trend surfaces developed for specific
conductances measured at monitoring wells and computed from apparent resistivity
197
-------
were shown to be in good agreement. Under favorable conditions, interpretation
of electrical sounding curves provides a basis for estimating specific
resistivity methods. This leads to a quantitative assessment of groundwater
contamination which compares favorably with that determined from monitoring
wells.
76:058-042
THE MODELLING AND CONTROL OF POLLUTION IN A RIVER SYSTEM,
Young, P-, Beck, B., and Singh, M.
Cambridge University, Department of Engineering, (England).
Journal of Hydrology, Vol. 28, No. 2/4, p 289-316, February 1976. (Published in
Amsterdam). 7 fig, 24 ref.
Descriptors: *Water pollution control, *Mathematical models, *River systems,
*Water quality, Dissolved oxygen, Biochemical oxygen demand. Effluents, Sewage,
Design, Simulation analysis, Optimization, Equations, Systems analysis, Path of
pollutants.
A river which is being used either as a source for potable supply or for
recreation requires an adequate and, if possible, an automatic control system
for maintaining pollution levels within reasonable bounds consistent both with
the needs of the community and the requirements for maintaining a satisfactory
ecological balance. This paper makes a preliminary examination of the design
of such a system by considering the dynamic modeling and control of dissolved
oxygen (DO) and biochemical oxygen demand (BOD) in a river system. This includes
a discussion on the derivation and verification of simple DO-BOD models for a
typical river, as well as initial thoughts on the operational control of sewage
effluent discharges in order to maintain specified levels of dissolved oxygen in
single and multiple reach river systems.
76:058-043
FLUVIC ACID AND AQUATIC MANGANESE TRANSPORT,
Zajicek, O.T. and Pojasek, R.B.
Massachusetts University, Department of Chemistry, Amherst, Massachusetts 01002
Water Resources Reaseach, Vol. 12, No. 2, p 305-308, April 1976. 2 fig, 3 tab,
30 ref.
Descriptors: Manganese, Return flow, Water quality, Rivers, Water resources.
Organic compounds.
The role of allochthonous organic substances in the solubilization of manganese
was investigated. The organic substances used were leachates of a variety of
watershed materials, fluvic acid, and a number of pure model compounds. It was
found that manganese concentration and water color were directly proportional,
in most cases, and that the organic materials comprising the color are effect
in dissolving manganese oxides and stabilizing the dissolved manganese in sol-
ution.
76:058-044
CHLORIDE ACCUMULATION NEAR CORN ROOTS UNDER DIFFERENT TRANSPIRATION, SOIL MOIS-
TURE, AND SOIL SALINITY REGIMES,
Sinha, B.K. and Singh, N.T.
Punjab Agricultural University, Department of Agricultural Engineering, Ludhiana,
Punjab, India
Agronomy Journal, Vol. 68, No. 2, p 346-348, March-April 1976. 3 tab, 8 ref.
Descriptors: Corn, Chloride, Soil water, Soil moisture, Saline soil. Salinity,
Transpiration, Root zone, Root systems. Root development.
The magnitude of 36C1 accumulation around roots of corn plants exposed to low,
medium, and high transpiration rates was studied in laboratory experiments using
Tulewal loamy sand salinized to ECe of 3 and 6 mmhos/cm with sodium chloride.
Radioautographs and quantitative measurements of 36C1 in high transpiration treat-
ment showed the highest concentration of the element in regions closest to the
198
-------
root. At high transpiration rates the chloride content of the soil close to the
roots increased while the same soil showed a decrease in the chloride content when
the plants were exposed to low transpiration treatment. Chloride concentrations
in the 'apparent free space' and soil close to the roots was two to three times
that in the bulk soil, depending upon the amount of water transpired/unit root
length. At higher transpiration rates, salt accumulation increased with greater
soil moisture content but was either unaffected or decreased closer to the root-
soil interface, when the transpiration rate was low. The results indicate that
the salinity tolerance limits of plants would be greatly influenced by the pre-
vailing evaporative demand.
76:053-045
LEACHING OF PHOSPHATE AND SELECTED CATIONS FROM SANDY SOILS AS AFFECTED BY LIME,
Chaiwanakupt, P. and Robertson, W.K.
Thai Ministry of Agriculture, Agricultural Chemistry Division, Bankok, Thailand
Agronomy Journal, Vol. 68, No. 3, p 507-511, May-June 1976. 12 fig, 2 tab, 7 ref.
Descriptors: Phosphorus, Phosphate, Leaching, Cations, Sandy soil, Lime, Ground-
water, Soil investigations.
It is important to determine if and to what extent P moves through some acid sandy
soils and, in view of the high cost of fertilizer P and the problems associated
with pollution of groundwater, what can be done to prevent or reduce the movement
when it occurs. Segmented columns, 25 cm in length and 5 cm in diam. , were used
to study P leaching in five mineral and one organic soil. A total of 25 or 50 cm
H20 was passed through the columns, containing soil from various depths, after
treatment in the top 2 cm with 0 to 600 ppm P tagged with 32P. Leaching of K,
Ca, and Mg occurred in all soils. The amount was generally related to the CEC or
the levels present in the extractable form before the leaching began. Leaching
of Fe and Al was determined only on soils where P leaching was appreciable. These
ions generally leached with P but there was a direct relationship between leached
and 0.1 N HC1 extractable ions. These data are of value in evaluating and deter-
mining .P and lime requirements.
76:05B-046
SOIL NITRATE LOSS DURING IRRIGATION: ENHANCEMENT BY PLANT ROOTS,
Volz, M.G., Ardakani, M.S., Schulz, R.K., Stolzy, L.H. and McLaren, A.D.
Connecticut Agricultural Experiment Station, Department of Plant Physiology, New
Haven, Connecticut 05604.
Descriptors: Nitrate, Leaching, Irrigation, Irrigation effects, Root development,
Barley, Denitrification, Organic matter.
Since roots can both absorb NO-3 and supply organic matter for NO-3 reduction by
soil microbes, the influence of a root system on No-3-N loss from soil solution
during irrigation was studied. Two Hanford sandy loam plots, one fallow, and
the other planted to CM-67 barley, were ponded for 44 hours with a solution con-
taining 100 ppm N and 46 ppm Cl- as KN03 and CaCl(2), respectively. Nitrate—N,
NO-2-N, NH(+)4-N, and Cl- concentrations in soil solution were determined and
related to N uptake by roots and microbial transformation of NO-3.
NUTRIENT MOVEMENT IN STREAMFLOW FROM AGRICULTURAL WATERSHEDS IN THE GEORGIA
COASTAL PLAIN,
eptment of Agriculture, Southern
Region, Southeast Watershed Research Unit, Tifton, Georgia _
Priced at'the 1976 Winter Meeting of the American Society of Agricultural Engin-
eers, December 14-17, 1976, Chicago, Illinois. 28 p, 12 fig, 3 tab, 7 ref.
Descriptors: Nitrates, Nitrite, Runoff, Watersheds, Return flow, Georgia, Stream
flow.
-------
As baseline information on nonpoint pollution, the monitoring of nitrogen, phos-
phates and chloride was begun in 1974 at 9 locations within a predominately
agricultural Upper Coastal Plain watershed (311 to 32,751 ha) at Tifton, Georgia.
Stream flow was continuously measured at all sites. Chemical load is computed
for one continuously sampled site, and seasonal relationships are noted.
76:053-048
CONCEPTS IN THE CONTROL OF NONPOINT WATER POLLUTION,
Frere, M.H., Woolhiser, D.A., Caro, J.H., Stewart, B.A., Wischmeier, W.H.
United States Department of Agriculture, Agricultural Research Service, Chickasha,
Oklahoma.
Presented at the National Water Resources and Ocean Engineering Convention of the
American Society of Civil Engineers, April 5-8, 1976, San Diego, California, 24 p,
8 fig, 2 tab, 11 ref.
Descriptors: Sediments, Salt salinity, Saline water, Saline soils, Nutrients,
Fertilization, Pesticides, Return flow.
Sediment, salt, nutrients, and pesticides are the principal types of pollutants
from nonpoint sources. Pollution from nonpoint sources is very difficult to iden-
tify and monitor. While standards have been established for municipal, industrial,
and agricultural uses of water, adequate standards have not yet been developed to
protect our environment. The lack of standards makes it very difficult to judge
the adequacy of any control program. In developing a control program there are
some methods that can be used over a broad area. These include education, incen-
tive, taxation, or legal penalties. All have good and bad points. Many of the
practices that must be used to control pollution are site specific; that is, the
practice must be designed for a specific field. In some cases, a practice may
solve one problem but create another. ARS has developed a set of flow charts to
assist land planners in selecting practices for croplands. These charts should
cause the user to ^recognize the possible pollution sources and to evaluate the
consequences of any practices selected to control these sources. Similar flow
charts could be developed for other land uses.
76:058-049
QUALITY MONITORING OF IRRIGATION WATER AND RETURN FLOWS IRRIGATION SEASON 1974,
Guitjens, J.C., Hamannah, C.N., and Miller, W.W.
Nevada University, Max C. Fleischmann College of Agriculture, Reno, Nevada.
Publication No. R114, July 1976. 81 p, 36 fig, 19 tab, 42 ref, 8 append.
Descriptors: Irrigation water, Return flow, Irrigation practices, Irrigation
effects, Tailwater, Water quality, Sampling.
Quantitive and qualitative measurements of irrigation applications (head water)
to and return flow (tail water) from selected fields were made a>t the Saram,
Heritage and Witt Ranches in the Carson Valley. Totalizing flow meters were used
to to measure quantity of irrigation water application as well as the quantity
of surface return flow (tail water) at each site. Water quality samples were
taken at each of these metering points at 12-hour intervals and analyzed for
temperature, dissolved oxygen, biochemical oxygen demand, ortho-phosphate, nitrate-
nitrogen, turbidity, electrical conductivity, pH, calcium + magnesium, sodium,
bicarbonate, chloride, and sulfate.
76:05B-050
MODELING PESTICIDES AND NUTRIENTS ON AGRICULTURAL LANDS,
Donigian, A.S., Jr., and Crawford, N.H.
Hydrocomp, Incorporated, Palo Alto, California 94304
Environmental Protection Agency Report No. 600-2-76-043, February, 1976.
Descriptors: Simulation, Runoff, Hydrology, Soil erosion. Nitrogen, Phosphorus,
Snowmelt, Watersheds, Pesticides, Return flow, Nutrients, Model studies.
Modifications, testing, and further development of the Pesticide Transport and
Runoff (PTR) Model have produced the Agricultural Runoff Management (ARM) Model.
200
-------
The ARM Model simulates runoff, snow accumulation and melt, sediment loss, pesti-
cide soil interactions, and soil nutrient transformations on small agricultural
watersheds. The report discusses the major modifications to and differences be-
tween the PTR and ASM Models. An energy-balance method of snow simulation and
a first-order transformation approach to nutrient modeling are included. Due
to lack of data, the nutrient model was not tested with observed data; testing
and refinement are expected to begin in the near future. Instrumented watersheds
in Georgia provided data for testing and refinement of the runoff, sediment and
pesticide portions of the ARM Model. Comparison of simulated and recorded values
indicated good agreement for runoff and sediment loss, and fair to good agreement
for pesticide loss. Pesticides transported only by sediment particles were sim-
ulated considerably better than pesticides that move both in solution and on
sediment. A sensitivity analysis of the ARM Model parameters demonstrated that
soil moisture and infiltration, land surface sediment transport, pesticide-soil
interactions, and pesticide degradation are the critical mechanisms in simulating
pesticide loss from agricultural watersheds.
76:05B-051
LOADING FUNCTIONS FOR ASSESSMENT OF WATER POLLUTION FROM NONPOINT SOURCES,
McElroy, A.D., Chiu, S.Y., Nebfen, J.w., Aleti, A., and Bennett, F.W.
Midwest Research Institute, Kansas City, Missouri 64110
Environmental Protection Agency Report No. 600/2-76-151, May, 1976.
Descriptors: Pollutants, Pollutant idenficatien, Pollution abatement, Water
pollution, Water pollution sources, Water quality, Water quality control. Water
resources.
The rates and magnitudes of discharges of pollutants from nonpoint sources do not
relate simply to source characteristics or source-related parameters. Evaluation
of the severity of this problem is hampered by the lack of tools to quantify pol-
lutant loads, and scanty and inprecise data on the interrelationships between
control measures and pollutant loads are a deterrent to formulation of control or
regulatory strategies. This User's Handbook is the result of a program which had
as one objective the development of nonpoint pollution loading functions for sig-
nificant sources and significant pollutants. The Handbook has two basic functions.
First, it presents loading functions together with the methodologies for their
use. Second, it presents some of the needed data, provides references to other
sources of data, and suggests approaches for generation of data when available
data are inadequate. A corollary function consists of assessments of the ade-
quacies of functions and their supporting inventories of data, and an assessment
as well of the extent to which pollutants and nonpoint sources are adequately
covered.
76:056-052
SIMULATION OF AGRICULTURAL RUNOFF,
Donigan, A.S., Jr., and Crawford, N.H.
Hydrocomp Incorporated, Palo Alto, California 94304
Presented at the National Water Resources and Ocean Engineering Convention of the
American Society of Civil Engineers, April 5-8, 1976, San Diego, California, 26 p,
7 fig, 15 ref.
Descriptors: Model studies, Return flow, Runoff, Sediments, Sedimentation, Pes-
ticides, Nutrients, Simulation analysis, Georgia, Water quality, Snowmelt, Water-
shed management.
Modifications, testing, and further development of the Pesticide Transport Runoff
Model have produced the Agricultural Runoff Management (ARM) Model. The ARM Model
simulates runoff, snow accumulation and melt, sediment loss, pesticide-soil
interactions, and soil nutrient transportation on small agricultural watersheds.
This paper briefly describes the ARM Model and discusses the results of Model
testing for simulation of runoff, sediment, and pesticide loss. Due to lack of
data, the nutrient model was not tested with observed data; testing and refine-
ment of the nutrient algorithms is expected to begin in the near future.
201
-------
76:058-053
NITRATE IN EFFLUENTS FROM IRRIGATED LANDS,
Pratt, P.F., Broadbent, F.E., McLaren, A.D., et al.
University of California, Kearney Foundation of Soil Science, Riverside, California
92502
Environmental Protection Agency Report No. PB-260 514, July, 1976.
Descriptors: Effluents, Leaching, Irrigated land, Percolation, Nitrogen cycle,
Water flow, Soil mechanics, Return flow, Nutrients.
The objective of this program is to develop a capability to predict nitrate leach-
ing in drainage and percolating waters from irrigated lands. The program is sub-
divided into projects: (1) extensive field approaches to assess nitrate concentra-
tions and quantities of nitrate-nitrogen leached; (2) intensive field trials using
stable isotopes of nitrogen to follow its fate through the soil-crop system; and
(3) nitrogen transformations in the soil and the microbiological and physical
factors that control these transformations. One project deals with computer model-
ing of the soil-crop-water system. There is a need to know as much as possible
concerning all aspects of the nitrogen cycle in the soil-plant-water system, i.e.,
cycling in the system, fluxes into harvested crops, drainage or percolating waters,
and denitrification and ammonia volatilization into the atmosphere. To predict
the leaching of nitrate from irrigated lands one must also understand and predict
water fluxes. One of the dominant factors in nitrogen use efficiencies in the
system is water management, thus many papers deal with the problem of predicting
downward fluxes of water in a dynamic situation involving irrigation cycles and
a growing crop.
76:058-054
FATE OF SALTS FROM WATER AND MANURE IN A 4-YEAR FIELD EXPERIMENT,
Pratt, P.P., Davis, S., Adriano, D.C., Bishop, S.E., and Laag, A.E.
California University, Department of Soil Science and Agricultural Engineering,
Riverside, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 264-276. 3 fig, 5 tab, 9 ref.
Descriptors: Calcium, Magnesium, Sodium, Potassium, Drainage water. Farm wastes,
Irrigation water, Return flow. Leaching.
The removal of Ca, Mg, Na and K in harvested crops and in drainage waters was
measured for a 4-year experiment with animal manures. For each cation the^amount
added in irrigation water and in manures minus removals in crops and by leaching
was assumed to have accumulated in the root zone of the soil. Calcium, Mg and K
accumulated in the root zone whereas there was a net loss of Na. The dominant
cation in the percolating water was Na, followed by Ca and then by Mg. Very
little K was removed by leaching. The dominate anion in the percolating water
was Cl. The determined increase in carbonate, expressed as CaC03, in the soil
was correlated with the calculated Ca accumulation in the root zone. The calcul-
ated Ca precipitated, as octacalcium phosphate assuming that all of the fixed P
converted to this form, was about 40% of the total Ca accumulation in the root
zone. Accumulation of soluble salts in the root zone accounted for only about
6% of the total cation accumulation and there was no increase in CEC. Thus, the
main mechanism for cation accumulation was precipitation or fixation.
76:058-055
DISTRIBUTION AND SEASONAL VARIABILITY OF MICRONUTRIENTS IN CERTAIN SALT AFFECTED
SOILS OF NORTHERN GREECE,
Papanicolaou, E.P., Anagnostopoulos, Tr., and Nobeli, C.
N.R.C. 'Democritos', Aghia Paraskevi, Athens, Greece.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 175-186. 12 fig. 19 ref.
Descriptors: Nutrients, Salts, Zinc, Iron, Copper, Boron, Soil salinity, Mangan-
ese, Leaching.
In two salt affected areas of Northern Greece the distribution and seasonal vari-
ability of B, Cu, Mn, Zn, and Fe along with the distribution and variability of
202
-------
Regard-
saltsare .presented. -The 1fvels of boron are high in the soils of both areas and
probably toxic to various plant species depending upon their relative tolerance
to this element. Copper and iron are probably present in normal levels while the
levels of manganese and zinc are probably low for the soils of both areas. Regar
ing seasonal variability there is evidence of leaching for boron, copper, zinc,
and iron and also for salts during the rainy period, while the data for manganese
are rather inconclusive. It is concluded that considerable amounts of micrbmif.ri-
ents will be leached out of these soils during reclamation.
76:05B-056
DETAILED RETURN FLOW SALINITY AND NUTRIENT SIMULATION MODEL,
Shaffer, M.J.
United States Bureau of Reclamation, Denver, Colorado.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 127-141. 8 fig, 18 ref.
Descriptors: Model studies, Simulation analysis, Drainage, Nitrogen, Nutrients,
Return flow, Water quality, Lysimeters, Irrigation effects, Salinity.
A computer model allows the simultaneous consideration of many complex chemical
and physical processes in the unsaturated and saturated zones. The model simulates
one-dimensional unsaturated flow and two-dimensional saturated flow (to tile
drains) , as well as chemical reactions and transport processes involving the major
cations and anions, and nitrogeneous species. The program also includes crop up-
take of water and nutrients. A numerical integration technique is utilized to
solve the appropriate differential equations, and generate transient predictions
throughout the soil-aquifer system, and at the drains. Utilization of a master
site technique allows application of the model to predict irrigation return flow
quality and quantity from large irrigated areas involving thousands of acres.
Verification has been accomplished on large acreages as well as field' plots, lysim-
eters, and laboratory columns. The model has a we 11 -documented user's manual and
has been applied to several large irrigation projects.
76:058-057
A CONCEPTUAL HYDROSALINITY MODEL FOR PREDICTING SALT LOAD IN IRRIGATION RETURN
FLOWS ,
Tanji, K.K.
California University, Department of Land, Air, Water Resources, Water Science
and Engineering Section, Davis, California.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 49-70. 6 fig, 6 tab, 13 ref, append.
Descriptors: Model studies, Simulation analysis, Salinity, Return flow, Irriga-
tion, Irrigation effects.
Presented herein is a description and applications of a steady-state conceptual
hydrosalinity model. The model may serve as a first-order approximation in lieu
of more detailed and refined models for evaluating mass emission of salts from
irrigated agriculture.
HYDROSALINITY MODELING OF IRRIGATION RETURN FLOW IN THE MESILLA VALLEY, NEW MEXICO
McLin, S.G., and Gelhar, L.W. ' .
New Mexico Institute of Mining and Technology, Socorro, New Mexico.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 28-48. 7 fig, 2 tab, 28 ref.
Descriptors: New Mexico, Model studies, Simulation analysis, Aquifers.
^^i^.STS.'Si'SS.SS SSi£,?"S f-iS-SSSI,
used in the model to transfer water between the aquifer and the stream may be
physical!? unrealistic in that it is independent of aquifer properties and water
203
-------
level. Improvements which relate the stream-aquifer interaction to aquifer proper-
ties and water level will be incorporated after the model has been tested over a
long time frame in its current form. Baseflow recession and well drawdown data
will be used to estimate the required aquifer parameters for the proposed model
improvements.
76:05B-059
IRRIGATION MANAGEMENT WHERE SALINITY SOURCES AND SINKS ARE PRESENT,
Hanks, R.J., Willardson, L.S., Jurinak, J.J., and Melamed, J.D.
Utah State University, Department of Soil Science and Biometerology, Logan, Utah
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 15-27. 6 fig, 1 tab, 14 ref.
Descriptors: Salinity, Salts, Saline soil. Irrigation water, Irrigation, Irriga-
tion effects.
Where sources and sinks are presented irrigation must be modified considerably-
Sources and sinks are found where salts have precipitated out of the soil solution
(Sink) or dissolved into the soil solution from solid phase salts (Source). An
empirical addition to a previous model was devised to account for these source-
sinks which were found to be very important in the field at Ashley Valley, Utah.
The model predicts that where sources are present, irrigation management varia-
tions has little influence on profile soil salinity for many years. Similarly
it predicted that salt concentration into the drainage water will not change for
many years regardless of the irrigation management used. Where a water table is
present irrigation less than enough to meet evapotranspiration demands will be
possible for many years with no adverse affect. These predictions agree with
field measurements.
204
-------
SECTION XXV
WATER QUALITY MANAGEMENT AND PROTECTION
EFFECTS OF POLLUTION (GROUP 05C)
76:05C-001
SIGNIFICANCE OF WATER QUALITY TO WATER RESOURCES,
Valantine, V.E.
Colorado River Board of California, Los Angeles, California.
Presented at the National Water Resources and Ocean Engineering Convention of the
American Society of Civil Engineers, April 5-8, 1976, San Diego, California, 13 p,
1 tab, 4 ref.
Descriptors: Water quality, Dissolved solids, Saline water, Economics, Water
resources, Water quality control.
Of the parameters of water quality, the dissolved solids or salinity parameter
requires special attention by water resources planners as it cannot be controlled
by filtration or biological reduction processes. As salinity levels in a water
supply rise, users of that supply are subject to detrimental effects that impose
substantial costs on the users. With the increased recognition of these detrimen-
tal effects and their costs in recent years, conflicts have arisen between the
groups of users causing salinity increases and those experiencing their impacts.
To resolve these conflicts, special public works projects have been and are con-
tinuing to be constructed, changes costly of both water and money have been and
are continuing to be made in the operation of water resource projects. and private
investment plans are restructured at increased costs.
76:05C-002
MANAGING SALINE WATER FOR IRRIGATION,
Texas Tech University, International Center for Arid and Semi-Arid Land Studies,
Lubbock, Texas
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976. 618 p.
Descriptors: Irrigation, Irrigation water, Irrigation effects, Salinity, Saline
soil. Saline water. Water quality, Water quality control, Energy, Saline water
systems, Salt balance, Salts, Model studies, Simulation analysis. Crop production.
Irrigation water salinity is becoming an increasingly serious problem as water of
less and less desirable quality is exploited for irrigation and as greater intens-
ity of water use leads to degradation. Deteriorating quality, combined with rapid-
ly increasing energy costs, has caused a crisis in water use in pump-irrigated
areas. Similarly, river waters have become more highly regulated, water evaporat-
ing from reservoirs concentrates the salts, and new irrigation projects aggravate
the salinity problem for downstream users. An international conference was held
at Texas Tech University in 1976 to assess the current state of knowledge about
managing saline water for irrigation and to present new information on how to cope
with salinity. Plant scientists, soil scientists, and engineers representing 20
countries participated in the sessions. Their findings are presented in this vol-
ume. The tone of the papers is one of optimism that moderately saline water can
be used successfully for irrigation if what is known already and what is being
learned now is used effectively. Mixed with the optimism is the realization that
careless management of saline irrigation water can be disastrous to the land and,
more importantly, to the people living on that land.
205
-------
SECTION XXVI
WATER QUALITY MANAGEMENT AND PROTECTION
WASTE TREATMENT PROCESSES (GROUP 05D)
76:050-001
EVALUATION OF A SULFUR-THIOBACILLUS DENITRIFICANS NITRATE REMOVAL SYSTEM,
Sikora, L.J., and Keeney, D.R.
Agricultural Research Service, Beltsville, Maryland.
Journal of Environmental Quality, Vol. 5, No. 3, p 298-303, July-September 1976.
6 fig, 3 tab, 32 ref.
Descriptors: *Denitrification, *Septic tanks, *Sewage treatment, *Domestic
wastes, *Nitrates, *Biological treatment. Bacteria, Sulfates, Groundwater,
Sulfur, Carbon, Inorganic compounds, Organic compounds, *Waste water treatment,
Kinetics, Chemical reactions.
A sulfur-Thiobacillus denitrificans nitrate removal system was evaluated as a
means of denitrifying nitrified septic tank effluent. Duplicate 10 by 64 cm
columns were filled with a 1/1 mixture (by weight) of elemental sulfur and
dolomite chips and were pretreated by recycling an enrichment culture of Thio-
bacillus denitrificans ATCC 23642 through the columns for 3 days. Continuous
passage of the nitrified septic tank effluent containing 40 micrograms of
nitrate/miililiter through the columns resulted in nearly complete nitrate
removal in 3.3 hours at steady state conditions. The denitrification kinetics
appeared to be first order in the range of nitrate concentrations used. Sulfate
was the major sulfur end product and was present at relatively high concentra-
tions (90 micrograms/milliliter). Passage of column effluent through 10 by 60
cm Plainfield sand columns did not significantly decrease sulfate levels. A
significant decrease in inorganic carbon content occurred with depth in the
columns, but changes in organic carbon were insignificant. Although the use
of this-nitrate removal system appears promising, sulfate contamination of the
groundwater may limit its applicability.
76:050-002
SOIL TEMPERATURES AND HEAT LOSS FOR A HOT PIPE NETWORK BURIED IN IRRIGATED SOIL,
Alpert, J.E., VanDemark, S.C., Fritton, D.D., and DeWalle, D.R.
Energy Resources Company, Envrionmental Science, Cambridge, Massachusetts.
Journal of Environmental Quality, Vol. 5, No. 4, p 400-405, October-December
1976. 5 fig, 3 tab, 15 ref.
Descriptors: *Heat, *Temperature, *Waste water disposal. Soil temperature,
Irrigation, Irrigation effects. Thermal conductivity, Heat flow, Model studies.
A 0.09-ha field prototype of a simultaneous waste heat and waste water disposal
system was constructed and instrumented. Data are reported for soil, pipe, soil
surface, and air temperatures; heat loss (0.068-0.117 cal cm(-2) min(-l)); and
soil thermal conductivity (3.61-5.63 meal (cm sec degrees C)(-1)). The data are
used to evaluate the heat flow theory which is currently being used to predict
the land area required for waste heat disposal with a buried hot water pipe net-
work. Predicted heat loss was consistently lower than experimental heat losses.
The results of the experiment indicate that substantial improvements need be
made in the existing theory to account for the transient heat flow and heat stor-
age. Research is currently being conducted to develop better predictive models.
76:050-003
OPTIMAL GROUND WATER QUALITY MANAGEMENT: WELL INJECTION OF WASTE WATERS
Willis, R.
Cornell University, School of Civil and Environmental Engineering, Ithaca,
New York.
Water Resources Research, Vol. 12, No. 1, p 47-53, February 1976. 2 fiq,
3 tab, 24 ref.
Descriptors: *Mathematical models, *Aquifers, *Waste water treatment, *Water
•206
-------
quality. Water treatment, Cost-benefit analysis, Groundwater, "Injection wells.
A mathematical model for optimal conjunctive utilization of the ground water
quality and quantity resources of unconfined aquifers was constructed. The sat-
urated zone of the ground water system was considered a component of a regional
waste treatment system. The model was designed so as to minimize the cost of
surface waste treatment while maintaining acceptable water quality levels through-
out the aquifer. Results indicate the feasibility of using secondary waste water
treatment (trickling filter) in conjunction with the assimilation capacity of the
unconfined aquifer for waste water degradation and disposal.
76:050-004
SOIL TEMPERATURE INCREASES INDUCED BY SUBSURFACE LINE HEAT SOURCES,
Rykbost, K.A., Boersma, L., and Jarman, G.D.
Long Island Vegetable Research Farm, Riverhead, New York 11901
Agronomy Journal, Vol. 68, No. 1, p 94-99, January-February 1976. 2 fig, 5 tab,
14 ref.
Descriptors: Temperature, Soil temperature, Heat, Heat transfer, Economics,
Energy, Energy conversion.
Generating electricity using the steam cycle produces large quantities of waste
heat. Conversion efficiencies range from 32 to 38% which means that for three
units of energy input about one unit of electrical energy is produced and two
units of waste heat must be disposed of. Circulating the condenser cooling water
through a network of underground pipes would result in warming the soil. The
present study was initiated to evaluate the effect of increased soil temperatures
on crop growth, the energy balance of the proposed system, and the economic
feasibility of the system. This report presents results of the energy balance
studies.
76:050-005
UNIFORM SLURRY SPREADING WITH A CENTER PIVOT IRRIGATION SYSTEM,
Chapman, J.A. and Myers, R.G.
Valmont Industries, Incorporated, Valley, Nebraska
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, December 14-17, 1976, Chicago, Illinois. 11 p, 4 fig, 3 ref.
Descriptors: Farm waste, Sprinkler irrigation, Irrigation, Irrigation practices,
Economics.
A design for the automated distribution of liquid manure through center-pivot
irrigation systems has been developed. The design is functionable and achieved
its basic goals. Under many conditions it appears to be highly cost effective
when compared to current liquid manure handling systems.
207
-------
SECTION XXVII
WATER QUALITY MANAGEMENT AND PROTECTION
ULTIMATE DISPOSAL OF WASTES (GROUP 05E)
76:05E-001
PROCEEDINGS OF THE CONFERENCE ON SALT AND SALINITY MANAGEMENT,
California University, Davis, California 95616
Proceedings of the Conference held at Santa Barbara, California, September 23-24,
1976, Report #38, December 1976. 166 p.
Descriptors: *Salts, *Salinity, *Water management, *Water quality control,
legislation, *Political aspects, *Institutions, Irrigation, Waste water disposal,
California, Operations, Technology, Soil tolerance, Water utilization.
(see 76:05G-020)
208
-------
SECTION XXVIII
WATER QUALITY MANAGEMENT AND PROTECTION
WATER TREATMENT AND DISTRIBUTION (GROUP 05F)
76:05F-001
VYREDOX-IN SITU PURIFICATION OF GROUNDWATER,
Hallberg, R.O., and Martinell, R.
Stockholm University, Department of Geology, (Sweden).
Ground Water, Vol. 14, No. 2, p 88-93, March-April 1976. 6 fig, 1 tab, 22 ref.
Descriptors: *Iron, *Manganese, Permeability, *Water treatment, Iron bacteria,
Clogging, Aeration.
The abundance and relative purity of groundwater guarantees its increase in
usage. In some localities, the content of iron and manganese in groundwater is
so high that these metals must be removed before the water can be used for
drinking or industrial purposes. Iron occurs in two states of oxidation in
nature, the divalent (ferrous) and trivalent (ferric) forms. The Vyredox
method developed in Finland and used now in Sweden oxidizes the ferrous ion,
which is soluble in water, to the ferric ion, which in insoluble, before the
water enters the well. The Vyredox method achieves a high degree of oxidation
in the strata around the well. The method makes use of iron oxidizing bacteria
and aeration wells. A number of aeration wells are placed in a ring around the
supply well. Water is forced down the aeration wells but first it is degassed
and then enriched with oxygen. The oxygen rich water provides a suitable habitat
for the iron oxidizing bacteria which assist in the oxidation of ferrous iron.
The process must be repeated at specific time intervals to avoid further
increases of iron content. The process of precipitating iron in the aquifer has
only a slight effect on aquifer permeability. Cloggage of the aquifer
surrounding the well should not occur for a period many times longer than the
life span of a typical well. Formulas provide estimates of the time in which
aquifer cloggage can occur and the radius at which aeration wells should be
placed.
209
-------
SECTION XXIX
WATER QUALITY MANAGEMENT AND PROTECTION
WATER QUALITY CONTROL (GROUP 05G)
76:05G-001
SULFURIC ACID FOR THE TREATMENT OF AMMONIATED IRRIGATION WATER: II. REDUCING
CALCIUM PRECIPITATION AND SODIUM HAZARD,
Miyamoto, S., and Ryan, J.
New Mexico State University, Department of Agronomy, Las Cruces, New Mexico.
Soil Science Society of America Journal, Vol. 40, p 305-309, 1976. 1 fig, 6 tab,
13 ref.
Descriptors: *Irrigation operation and maintenance, *Hydrogen sulfide, *Mine
wastes, Irrigation efficiency, Water utilization, Water quality. Southwest
U.S., Infiltration, Ammonia, Lime, Chemical wastes, Industrial wastes, Pollution
abatement. Fertilizers.
Effects of the application of ammonia and sulfuric acid to ammoniated water on
Calcium precipitation and Na-Hazard of irrigation water are evaluated theoreti-
cally, using known relations of ion equilibria, and tested with laboratory and
greenhouse experiments. Results show severe precipitation of Ca2+ when ammonia
is applied to alkaline irrigation water. Ammonia application also increases
exchangeable Na and NH4, and can reduce water infiltration rates, especially
when irrigation waters contain high Na+ relative to Mg2+ and Ca2+. Sulfuric
acid applied to ammoniated water neutralizes OH- produced by ammonia application,
reducing Ca precipitation and exchangeable Na. This prevents a decline in infil-
tration rates. Sulfuric acid, now available as a pollution abatement by-product
in the Southwest, can be used for correcting excessive lime incrustation or poor
water penetration induced by the use of hydrous or aqua ammonia without corrod-
ing irrigation systems.
76:05G-002
GUIDELINES FOR SEDIMENT CONTROL IN IRRIGATION RETURN FLOW,
Carter, D.L.
Agricultural Research Service, Snake River Conservation Research Center,
Kimberly, Idaho.
Journal of Environmental Quality, Vol. 5, No. 2, p 119-124, April-June 1976.
1 tab, 17 ref.
Descriptors: *Return flow, *Erosion control, *Irrigation practices, *Irrigation
water, *Sediment control, Water quality. Agriculture, Runoff, Flow, Furrow
irrigation, Erosion, Cultivation, Filtration.
Sediments in irrigation return flows arise mostly from erosion in furrows during
irrigation, and sediment concentrations vary widely from near zero to several
thousand ppm. Reducing both erosion and runoff"would decrease the sediment in
return flows. Technology is available for reducing Doth erosion during irriga-
tion and soil loss from the land, and for removing sediments from return flows.
This technology was discussed, and the following guidelines were suggested: (1) "
Eliminate or reduce irrigation return flows when conditions permit using irriga-
tion methods with little or no runoff. (2) Control the irrigation furrow slope
so that the run is across the steepest slope or on the contour. Decrease the '
slope near the end of the furrow to reduce the flow velocity and increase sedi-
mentation. (3) Control the furrow stream size and make proper stream adjust-
ments. Adequate water measuring equipment and controls are essential for proper
stream size control. (4) Shorten the run length. (.5) Control the irrigation
duration to reduce the number of irrigations per season. Alternate furrow irri-
gation reduces the contact between soil and flowing and subsequent erosion. : (6)
Cultivate only when necessary, avoiding excessive soil loosening which increases
erosion and soil loss. (7) Control tailwater by assuring that it flows.;Slo&l:y
enough that sediments settle before the water leaves the field. Filtering
through grass strips removes sediments. (8) Utilize sediment retention basins
to remove sediment from return flows.
210
-------
76:050-003
HYDROLOGY OF SALINE SEEPS IN THE NORTHERN GREAT PLAINS,
Doering, E.J., and Sandoval, F.M.
Agricultural Research Service, Northern Great Plains Research Center Mandan
North Dakota.
Transactions of the American Society of Agricultural Engineers, Vol. 19 NO 5
p 856-861, 865, September-October 1976. 7 fig, 4 tab, 16 ref. ' '
Descriptors: *Seepage, *Groundwater movement, *Water quality, *Seepage control,
*North Dakota, On-site investigations, On-site tests, Measurement, Instrumenta-
tion, Saline water, Salinity, Nitrates, Chlorides, Hydrographs, Hydrology,
Groundwater, Subsurface drainage. Tile drainage, Hydrologic data.
Hydrologic data collected between 1970 and 1975 show: (1) that seeps are sus-
tained by local recharge, i.e., by soil water that percolates past the root
zone of the adjacent upslope landscape, (2) that seep development is closely
related to recent climatic and cultural events, and (3) that hydraulic control
can be quickly accomplished with interceptor drains. Effluents from two drains
were saline, with nitrate concentrations consistently high enough to be hazard-
ous to health of humans and livestock.
76:056-004
THE ROLE OF SYSTEMS ANALYSIS IN THE USE OF AGRICULTURAL WASTES,
Schlute, D.D., and Kroeker, E.J.
Manitoba University, Department of Agricultural Engineering, Winnipeg, Manitoba,
Canada.
Journal of Environmental Quality, Vol. 5, No. 3, p 221-227, July-September 1976.
4 fig, 21 ref.
Descriptors: *Systems analysis, Wastes, Model studies. Simulation analysis,
Linear programming, Dynamic programming.
Agricultural waste management is a multidisciplinary field which has grown in
an attempt to solve problems of agricultural by-product utilization and disposal.
Development of meaningful solutions to agricultural waste management problems
will be much simpler if practitioners and researchers educate one another and
together work to solve the different problems of the producer. Many disciplines
have already become involved in the problem-solving process; yet, there is a
need for a generalist in agricultural waste management who can bridge disciplin-
ary gaps and promote' effective cooperation between specialists in various fields
of study. Systems analysis can serve a useful purpose in agricultural waste
management by providing a focal point for cooperation between disciplines work-
ing on various aspects of the problem. Systems analysis has been used to: (i)
provide a common structure for comparison of agricultural waste management
strategies; (ii) identify processes or links within waste-utilization systems
which are costly or sensitive to operating conditions; (iii) predict effects of
external constraints such as government policy, fertilizer taxes, and prices on
the effectiveness of waste-utilization strategies; (iv) yield information to
predict where research funds would be spent most effectively; and (v) assist in
technology transfer from researchers to practitioners through the aid of compu-
ter-based education models.
76:05G-005
DIFFUSE AGRICULTURAL POLLUTION: THE ECONOMIC ANALYSIS OF ALTERNATIVE CONTROLS,
Schneider, R.R., and Day, R.H.
Wisconsin University, Department of Agricultural Economics, Madxson, Wisconsin.
Wisconsin Water Resources Center, Madison, Technical Report WIS WRC, 1976.
98 p 76-02, 16 fig, 30 tab, 8 maps, 72 ref. 2 append. OWRT A-063-WIS(2).
14-31-0001-5050.
Descriptors: *Agricultural runoff, *Nitrates, 'Sediment yield, *Sediments,
'Nutrients, Agriculture, *Farm management, Crops, 'Fertilizers, *Water pollution
sources, *Farm wastes, Legislation, *Wisconsin, Water policy. Water pollution
control, Alternative planning.
This study examines policies designed to curtail 3 types of diffuse agricultural
pollution! (1) Runoff from winter-spread manures; .(2) Sediment in rill and
211
-------
sheet erosion; (3) Nitrate polution of groundwater resulting from field-applied
manure and chemical nitrogen. The following policies are tested on four farm
sizes at 7 locations: (1) enfource Wisconsin's Model Sediment Control Ordinance;
(2) prohibit all manure spreading in winter; (3) prohibit winter manure spread-
ing on sloped land; (4) prohibit winter manure spreading close to streams, lakes,
or open ditches; (5) restrict the excess of applied nitrogen over estimated plant
uptake of nitrogen; (6) combine 1, 3, 4, and 5 above; (7) combine 1, 2, and 5
above,; (8) restirct average total sediment yield. The effects of these policies
on efficiency of resources allocation, and their differential impact in the gla-
ciated and unglaciated regions of the state are explored. The framework for
efficiency analysis is that of a partial competitive equilibrium. The estimation
of appropriate data for the analysis is an important and integral part of the
study. The marginal cost of pollution reduction is calculated for each policy
and the marginal cost curve is generated for a sediment policy on selected farms.
These data are presented along with the physical quantities of pollutant reduction.
76:050-006
THE INFLUENCE OF TRICKLE IRRIGATION ON THE QUALITY OF IRRIGATION RETURN FLOW,
Brown, K.W., Gerard, C.J., DeMichele, D.W., Sharpe, P.J.K., and Hipp, B.W.
Texas A and M University, Department of Soil and Crop Sciences, College Station,
Texas.
Texas Water Resources Institute, College Station, Completion Report TR-70, March,
1976. 77 p, 3 fig, 19 tab, 10 ref. OWRT B-156-Tex(l), 14-31-0001-4128.
Descriptors: Water quality, *Leachate, Leaching, Sorghum, *Rio Grande River,
*Return flow, *Texas, Nitrates, *Lysimeters, *Salt balances, *Computer models,
Simulation analysis. Soil treatment, Crop production, Irrigation water.
The influence of trickle irrigation on the quality of irrigation return flow was
investigated in a field study and by means of computer simulation models. Six
undisturbed buried monolith lysimeters were utilized to quantify the leachate
from treatment including two different qualities of irrigation water applied
through a trickle irrigation system. Both moisture and salt balances were
followed indise and outside the lysimeters during a growing season the remainder
of the calendar year. A sorghum crop was grown on the lysimeters and in the
adjacent area. Irrigation was scheduled based on pan evaporation losses. The
irrigation water of high salt content was obtained from a deep well while the
irrigation water of low salt content was drawn from the district irrigation
canal. The water balance monitored by the neutron probe showed that differences
between inside and outside lysimeters were small. The soil contained significant
concentration resulting from irrigation treatment are difficult to see after one
year of monitoring. Differences between paired lysimeters are large indicating
large variability in soil characteristics across the field. Differences in water
use inside and outside the lysimeters indicated that during the 1974 growing
season, which was dryer than normal, the sorghum crop may have extracted approx-
imately 8% of the water required from the water table. Yield and growth data
indicated that the plant root environments inside and outside lysimeters were
relatively comparable. Nitrogen, saline water and irrigation treatments did not
significantly influence growth and yields of sorghum in 1974.
76:05G-007
LOSSES OF NITROGEN IN SURFACE RUNOFF IN THE BLACKLAND PRAIRIE OF TEXAS,
Kissel, D.E., Richardson, C.W., and Burnett, E.
Texas Agricultural Experiment Station, College Station, Texas.
Journal of Environmental Quality, Vol. 5, No. 3, p 288-293, July-September 1976.
4 tab, 1 fig, 16 ref.
(see 76:056-018)
76:05G-008
AN OPTIMIZATION MODEL FOR REGIONAL WATER QUALITY MANAGEMENT,
McNamara, J.R.
Lehigh University, Department of Economics, Bethlehem, Pennsylvania.
Water Resources Research, Vol. 12, No. 2, p 125-134, April 1976. 3 fig, 2 tab,
26 ref.
212
-------
Descriptors: *Water quality, *Management, *Pollution abatement, "Optimization
-Hudson River, Waste treatment, Marginal costs, Flow, Regulation, Biochemical
' 1
models,
The use of combinations of pollution abatement techniques will become imperative
trea^n? ll*lL? ""^ ^ f^^ ™& the 'Potion of secondary*"^
treatment at each point of discharge becomes inadequate to maintain the desired
levels of water quality. At high levels of waste treatment, costs rise non-
linearly with the fraction of waste removed. The marginal cost of each of a
series of pollution abatement techniques at a given location is likely to be
less than the marginal cost of a single technique operated very intensively
Herein, a nonlinear programming model for water quality management is developed,
capable of assessing the contributions of a variety of pollution abatement tech-
niques and compatible with an efficient solution procedure. Formulated as a geo-
metric programming problem, the model is intended to be a preliminary selection
device permitting the planner to compare alternative configurations and to sketch
a roughly optimal solution. It is shown that this formulation permits the simul-
taneous consideration of waste treatment processes, bypass piping, flow regulation,
and artificial aeration in determining a least-cost solution to a given water
quality management problem. The model is applied to the upper Hudson River of
New York.
76:050-009
FIELD DRAINAGE WITH MANIFOLD WELL POINTS,
Rektorik, R.J.
Agricultural Research Service, Weslaco, Texas.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 1,
p 81-84, January-February 1976. 2 fig, 4 tab, 6 ref.
Descriptors: *Drainage systems, *Drainage wells, *Rio Grande River, *Texas,
Water quality control, Aquifers, Plastic pipes, Well screens, Water table,
Dewatering, Drawdown, Drainage, On-site investigations, Leaching, Cost analysis,
Depth, Transmissivity, Storage coefficient, Pumping, Electric power costs,
Centrifugal pumps, Reclamation, Root zone, Hydraulic gradient, Cathodic protec-
tion, Corrosion, Electrolysis.
A field study of a maniforl well point system was conducted in a highwater table,
shallow aquifer in the lower Rio Grande Valley of Texas. The objectives of the
study were to determine how effectively well point drainage systems work, how
long they would last, their design, and their installation and operational cost,
PVC pipe was used for the wells and manifold piping, and plastic screens were
used for the well points. These materials offer much resistance to both corro-
sion and electrolytic problems and, as such, show promise for a long service life.
The cost of well point systems at about $250/ha is materially lower than the
(370-$500/ha for pipe drain systems. The design of well point systems depends
on variations in aquifer parameters. Straight line configurations are most eco-
nomical to construct but do not produce the most uniform drawdown. Water removal
of about 0.26 1/s/ha provided adequate control of the water table in the study
ares and permits leaching of salts by irrigation or rainfall.
EQUITY'CONSIDERATIONS IN CONTROLLING NONPOINT POLLUTION FROM AGRICULTURAL SOURCES,
Miller, W.I., and Gill, J.H. .
Purdue University, Department of Agricultural Economics, Lafayette, Indiana.
Water Resources Bulletin, Vol. 12, No. 2, p 253-261, April 1976. 3 tab, 12 ref.
Descriptors: *Water pollution control, *Agriculture, *Linear programming, *Farms,
Size, ^Economic impact, "Indiana, Constraints, Research, Mathematical models,
Systems analysis, Water pollution sources.
The objectives of the research reported in this paper are: (1) to compare the
relative economic impact on large and small farms of applying a statewide soil
213
-------
and between different topographic areas resulting from application of taxes-
subsidies on soil loss. Accomplishing these objectives will illuminate some of
the equity consequences of application of two quite different approaches to con-
trolling nonpoint pollution from agricultural sources. A linear programming
model has been used to analyze the objectives. The model includes an objective
function to maximize model and includes objective function to maximize net revenue
to the farm firm by selecting among a wide array of management parctices applied
on several different soil groups. It is concluded that the imposition of standard
state soil loss rules has an unequal impact on the income of different size firms
located in different topographic regions.
76:05G-011
POLLUTER DISCRIMINANT ANALYSIS,
Tock, D.G., and Wright, G,P.
Krannert Graduate School of Industrial Administration, Lafayette, Indiana.
Water Resources Research, Vol. 12, No. 4, p 613-616, August 1976. 1 fig, 3 ref.
Descriptors: *Water pollution control, *Data collections, Coasts, Great Lakes,
Statistical methods, Mathematical models, Systems analysis.
A unique water pollution data base for the U.S. coastal waterways and Great Lakes
that has been evolving since 1965 is discussed. The pollution statistics in this
data base are used to develop a model, employing multiple discriminant techniques,
to determine which pollution incident report variables will discriminate the pol-
luter who reports his spill from the polluter who does not report his spill. The
results of the analysis indicate that as few as nine out of a possible sixty
variables provide reasonable discriminatory power.
76:05G-012
ON THE INCOME DISTRIBUTIONAL EFFECTS OF ENVIRONMENTAL MANAGEMENT POLICIES,
Campbell, H.F.
British Columbia University, Department of Economics, Vancouver, British Columbia.
Water Resources Research, Vol. 12, No. 5, p 1077-1080, October 1976. 3 tab, 6 ref,
1 append.
Descriptors: *Water resources, *Income distribution, *Effects, *Environmental
control, *Effluents, *standards, *Treatment, Technology, Behavior, Simulation
analysis, Prices, Mathematical models, Systems analysis, Optimum development plans.
This paper analyzes the effect of three environmental policy instruments—effluent
charges, effluent standards, and effluent treatment subsidies—-in the context of
a two-person two-firm general equilibrium model in which the distribution of in-
come varies with the choice of policy instrument. It is demonstrated that, under
reasonable assumptions about the income distribution process and the nature of
consumer preferences, each policy instrument corresponds to a different optimal
quantity of effluent and a different set of optimal prices. The implication of
this result is that consideration of income distributional effects should play an
integral part in the formulation of optimal environmental management policies.
76:056-013
CATHODIC PROTECTION WELLS AND GROUNDWATER POLLUTION,
Ritchie, E.A.
California State Department of Water Resources, Sacramento, California.
Ground Water, Vol. 14, No. 3, p 146-149, May-June 1976. 3 fig, 5 ref.
Descriptors: *Cathodic protection, *Water pollution, *Hydraulic conductivity,
Groundwater, Infiltration, Wells, California, *Corrosion.
The cathodic protection well can endanger groundwater quality by providing a path
for pollutants to reach usable water supplies. Cathodic protection wells allevi-
ate electrolytic corrosion of pipelines, tanks and other installations situated
in a corrosive environment. This is done by redirecting the current to a substi-
tute anode which then deteriorates, instead of the structure being protected.
Cathodic protection wells normally are from 100 to 500 feet in depth and 8 to 10
inches in.diameter. To prevent cathodic protection wells from acting as convey-
ences for pollutants, they must be properly designed and constructed, and when
214
-------
SECTION XXXIV
WATER RESOURCES PLANNING
WATER LAW AND INSTITUTIONS (GROUP 06E)
76:06E-001
AGRICULTURAL LEGISLATION'S POTENTIAL IN REDUCING DISCHARGE OF POLLUTANTS,
Gambell, E.L.
United States Department of Agriculture, Program Analysis, Environmental Quality
and Land Use Staff, Agricultural Stabilization and Conservation Service,
Washington, D.C.
Water Resources Bulletin, Vol. 12, No. 6, p 1171-1179, December 1976. 12 ref.
Descriptors: Agriculture, Pollution abatement. Legal aspects. Legislation,
Agricultural runoff. Return flow. Water quality -
Agricultural lands (including most forest lands) make up almost four-fifths of the
total land area of the United States and include, or are traversed by, perhaps an
equal proportion of our ground and surface waters. Therefore, a very large part
of our environment is directly 'agriculture-related' in any consideration of the
discharge of pollutants. Several important Federal and State laws relate to the
control or abatement of agriculture-related pollution. Existing legislation
generally mandates the control or abatement of pollution (from point or nonpoint
sources) or authorizes the use of public funds or other resources for such purposes.
Some of these laws can be effective instruments in keeping pollutants from being
discharged into surface or ground waters or into the air, but the degree to which
som pollutants originating from agricultural lands and operations constitute a
serious environmental hazard in waters remaining controversial. Although most of
the technology exists to reduce greatly the movement of these pollutants, invest-
ments are often required which benefit the nonfarm public without economic returns
to the farmer. Whether a zero discharge is either an environmentally or
economically feasible alternative to more limited or selective control, is
explored. However, if the public is willing to bear its reasonable share of the
cost for clear air and water, the needed basic legislation already largely exists.
Under it, agricultural land holders may apply program standards and use their own
and available program resources to bring about effective control or abatement of
pollutants.
76:06E-002
INSTITUTIONAL PROBLEMS OF ENERGY PRODUCTION,
Trelease, F.J. Ill
Wyoming Water Planning Program, State Engineer's Office, Cheyenne, Wyoming 82001
Water Resources Bulletin, Vol. 12, No. 5, p 931-939. October 1976. 2 fig, 2 tab,
3 ref.
Descriptors: Institutional constraints, Institutions, Planning, Permits, Energy,
Oil shale, Wyoming, Coals, Water resources.
The Rocky Mountain and Great Plains Regions of the West have recently come into
focus as a fuel source for an energy hungry nation. Development of energy re-
sources will require compliance with, or regulation under many established
'institutions'. New institutions, such as plant siting permits and tougher en-
vironmental and land use controls are being established. A year ago the nation
seemed to be moving rapidly towards Project Independence—achieving national
self-sufficiency in energy production. Now there appears to be several factors
that are combining to impede the energy development, and these include national,
regional, and local policies, problems associated with financing, environmental
concerns, and reluctance to change (or be impacted by development). The institu-
tion of the courts has even come into paly. Western coal, oil shale, and uranium
resources will require water to convert them into usable forms of energy. This
is true whether the resources are converted into fuel or electricity at the mine
sites or elsewhere. Western water law and a broad background of water develop-
ment experience should pave the way for providing the water necessary for develop-
ment of the energy minerals. On the other hand, the water institutions may be
formed in ways or may be utilized in ways to create another impediment to energy
231
-------
development. Wyoming water resources and water law will be discussed in this
paper as an example.
76:06E-003
PROCEEDINGS OF THE CONFERENCE ON SALT AND SALINITY MANAGEMENT,
California University, Davis, California 95616
Proceedings of the Conference held at Santa Barbara, California, September 23-24,
1976, Report # 38, December 1976. 166 p
Descriptors: *Salts, *Salinity, *Water management, *Water quality control,
legislation, *Political aspects, *Institutions, Irrigation, Waste water disposal,
California, Operations, Technology, Soil tolerance, Water utilization.
(see 76:05G-020)
232
-------
SECTION XXXV
WATER RESOURCES PLANNING
NONSTRUCTURAL ALTERNATIVES (GROUP 06F)
76:06F-001
LAW, HYDROLOGY, AND SURFACE-WATER SUPPLY IN THE UPPER COLORADO RIVER BASIN,
Jacoby, G.C. Jr., Weatherford, G.D., Wegner, J.W.
Lamont-Doherty Geological Observatory, Palisades, New York.
Water Resources Bulletin, Vol. 12, No. 5, p 973-984, October 1976. 4 fig, 24
ref.
Descriptors: *Colorado River Basin, *Water resources development, *Colorado
River Compact, *Water law. Legal aspects. Hydrology, Water supply. Surface
waters, River basin development, Water resources. Water Allocation (Policy),
Water demand, Streamflow, Water policy, Groundwater, Boulder Canyon Project Act,
Colorado River, Dendrochronology.
The relationship between law and hydrology in water resources development is
discussed. Law attempts to allocate a limited and valuable resource while
hydrology tries to define the limits of the resource. In the past an inadequate
data base has made hydrologic estimates difficult and political factors pushed
the law into possibly conflicting commitments in the Colorado River Basin. The
water allocation process and the role of hydrology in defining the risk of
deficiency are described and a historical overview of the interaction between
law and hydrology is presented. Using tree-ring research, hydrologists have
produced a more definite data base and thus given legal policy makers more
reliable information. As development approaches the resource limit in the
Upper Colorado River Basin, lawyers and hydrologists must act in concert toward
the equitable solution of allocation and reallocation problems.
233
-------
SECTION XXXVI
RESOURCES DATA
DATA ACQUISITION (GROUP 07B)
76:07B-001
CORRECTION OF "TUBE CONTRIBUTION" INTERFERENCE IN THE DETERMINATION OF HEAVY
METALS BY X-RAY SPECTROSCOPY USING THE "ADDITIONS TECHNIQUE",
Keramidas, V.Z., and Fanning, D.S.
Maryland Agricultural Experiment Station, Department of Soil Science, College
Park, Maryland.
Soil Science Society of America Journal, Vol. 40, No. 6, p 857-860, November-
December 1976. 2 fig, 1 tab, 7 ref.
Descriptors: *Heavy metals, Zinc, Copper, Nickel, Soil chemistry. Soil proper-
ties, Soil investigations. X-ray spectroscopy-
Cr and W X-ray tubes emitted not only the target characteristic lines but the
lines of Fe, Zn, Cu, and Ni as well. Such extraneous radiation, which probably
originates primarily from contamination of the tube target by the metals and is
referred to as "tube contribution," may lead to erroneous qualitative interpre-
tation of X-ray spectra because peaks of the elements may appear in the spectra
when the element is not present in the sample. The additions (or spiking)
technique allows matrix problems to be overcome in the quantitative measurement
of Zn, Cu, and Ni in soil and other materials, but an accurate estimation of the
background under the peak is essential.
76:078-002
A SEMIAUTOMATED PROCEDURE FOR TOTAL NITROGEN IN PLANT AND SOIL SAMPLES,
Gallaher, R.N., Weldon, C.O., and Boswell, F.C.
Florida University, Department of Agronomy, Gainesville, Florida.
Soil Science Society of America Journal, Vol. 40, No. 6, p 887-889, November-
December 1976. 2 fig, 1 tab, 12 ref.
Descriptors: *Nitrogen, Laboratory tests, Laboratories, Soil investigations,
Soil properties.
This study evaluated inexpensive alternatives for the determination of total N
in plant and soil samples. Plant and soil samples which varied widely in N
concentration were digested in a 126-sample-capacity Al block digester followed
by determination of total N with the ammonium electrode in a semiautomated
reaction vessel assembly. The proposed Ammonium electrode semiautomated (AES)
procedure was compared to standard micro-Kjeldahl and aluminum block digested-
steam distilled-titrated (ABDDT) procedures. Thirty to 50 more samples could be
analyzed per 8-hour day with the proposed simiautomated procedure as compared
to standard micro-Kjeldahl methods. The precision of the methods were comparable
but significantly more N was found by using the ABDDT procedure.
76:07B-003
ESTIMATING WATER SALINITY WITH GEOPHYSICAL EARTH RESISTIVITY EQUIPMENT,
Halvorson, A.D., and Reule, C.A.
United States Department of Agriculture, Agricultural Research Service, Western
Region, P.O. Box 1109, Sidney, Montana.
Soil Science Society of America Journal, Vol. 40, No. 1, p 152-153, January-
February 1976. 2 fig, 1 tab, 5 ref.
Descriptors: *Salinity, *Salts, Laboratory tests. Soil salinity. Water salinity.
A procedure is described for estimating salinity of water samples in the field
using a geophysical earth resistivity meter and four-electrode conductivity cell.
Using field collected water samples, a linear relationship of Y = 1.02(X) + 0.12,
r = 0.996, was obtained between Electro conductivity at 25 degrees centigrade
values determined using a commercial laboratory bridge and cell (Y), and those
determined using an earth resistivity meter and an easily fabricated, four-
234
-------
electrode conductivity cell (x).
76:07B-004
A METHOD FOR SECTIONING SATURATED SOIL CORES,
Reddy, K.R., and Patrick, W.H. Jr.
Louisiana State University, Department of Agronomy, Baton Rouge, Louisiana
Soil Science Society of America Journal, Vol. 40, No. 4, p 611-614, July-August
1976. 3 fig, 2 tab, 5 ref.
Descriptors: Laboratory tests. Sampling, Soils, Soil physical properties.
Soil investigations, Ions, Cores.
A simple system for sectioning water-saturated cores without prior freezing
is described. The method describrd can be used for studying the distribution
and movement of ions in soil or sediment cores prepared in the laboratory or
obtained in undisturbed form from the field. The average coefficient of varia-
tion was 4.8% for the sectioning of the cores prepared in the laboratory and
10.5% for the sectioning of the cores obtained from the field.
76:07B-005
IN SITU MEASUREMENT OF GAS DIFFUSION COEFFICIENT IN SOILS,
Lai, S.H., Tiedje, J.M., and Erickson, E.
Michigan State University, Department of Crop and Soil Sciences, East Lansing,
Michigan.
Soil Science Society of America Journal, Vol. 40, No. 1, p 3-6, January-
February 1976. 4 fig, 3 tab, 12 ref.
Descriptors: Soils, Soil investigations, Soil profiles, Gas chromatography,
Soil properties. Carbon dioxide.
A method for determination of the gas diffusion coefficient of soils without
disturbing the natural state of the soil was developed. The method was based
on the theory of radial diffusion of a finite quantity of gas into a semi-infin-
ite porous medium. Needles were inserted into the soil through which O2 was
injected. The change of concentration of the injected 02 was determined by
gas chromatography through the same needle after increasing periods of time.
A least square fit between the measured 02 concentrations and that of the
theoretical values was conducted to find the best fit value of the diffusion
coefficient. The diffusion coefficient determined by the proposed method was
used to calculate the flux of CO2 in field soils. The flux so calculated was
compared to that measured from the field with good agreement. The method was
used in several different field soils and conditions to determine the diffusion
coefficients.
76:07B-006
EVALUATION OF METHODS FOR PRESERVING THE LEVELS OF SOLUBLE INORGANIC PHOSPHORUS
AND NITROGEN IN UNFILTERED WATER SAMPLES,
Klingaman, E.D., and Nelson, D.W.
Purdue University, Agricultural Experiment Station, Lafayette, Illinois.
Journal of Environmental Quality, Vol. 5, No. 1, p 42-46, January-March 1976.
3 tab, 11 ref.
Descriptors: *Nitrogen, *Phosphorous, *Nitrate, Sampling, Laboratory test,
Surface runoff, Drainage water.
Several methods for preserving the levels of soluble inorganic phosphorus (SIP),
ammonium, and nitrate in surface runoff, tile drainage water, and river water
were evaluated. The best overall technique for preservation of water samples
for P and N analysis appeared to be storage at subzero temperatures. The SIP
concentration in samples was also stabilized by addition of HgC12 (40 mg/liter)
and storage at 4C; however, the ammonium and nitarte levels in samples were
not preserved for long periods of time (12 weeks) by this technique. The
soluble inorganic N levels in water samples were preserved by addition of
phenylmercuric acetate (20 mg/liter) and storage at 4C, but use of this
procedure increased the SIP concentration in some samples during storage.
Storage of samples at 4C or 23C without addition of a chemical preservative
235
-------
resulted in large changes in soluble inorganic P and N contents.
75:07B-007
EFFECT OF PRETREATMENT ON LOSS OF NITROGEN-15-LABELLED FERTILIZER NITROGEN FROM
WATERLOGGED SOIL DURING INCUBATION,
McKenzie, E. Jr., and Kurtz, L.T.
Prairie View A and M University, Prairie View, Texas.
Soil Science Society of America Journal, Vol. 40, No. 4, p 534-537, July-August
1976. 1 fig, 3 tab, 27 ref.
Descriptors: *Denitrification, *Nitrogen, *lncubation, Soil chemical properties.
Soil tests, Soil investigations, Soils, Nutrients.
Soil preparation treatments (field-moist, intact cores; oven dried, intact cores;
and oven dried, crushed, screened soil) greatly influenced fertilizer nitrogen
loss under waterlogged conditions in the laboratory. Nitrogen (300 pp2m) as
N-15-labelled calcium nitrate was added to samples from selected horizons of
Drummer silty clay loam and they were subsequently covered with water and incuba-
ted for 0, 4, 8, 16, and 32 days. Samples of upper (above 51 cm) soil horizons
were incubated at 21C while those from deeper horizons were incubated at 18C.
Oven-drying and crushing of the soil during preparation increased fertilizer
nitrogen loss. Only 34% of the fertilizer nitrogen disappeared from field-moist,
intact soil cores while approximately 90% disappeared from both oven-dried,
intact cores and crushed screened samples. Maximum rate of denitrification of
fertilizer nitrogen in field-moist, intact cores was 3.58% of the applied nitro-
gen per day. This rate was approximately one-third of that in the oven-dried,
intact cores and one-ninth of that in the oven-dried, crushed samples.
76:07B-008
CATION-EXCHANGE CAPACITY OF ACID SOILS USING ALUMINUM CHLORIDE AND BARIUM
CHLORIDE-TRIETHANOLAMINE,
Alexander, E.B.
United States Forest Service, Department of Soil Science.
Soil Science Society of America Journal, Vol. 40, No. 6, p 961-963, November-
December 1976. 1 tab, 6 ref.
Descriptors: Laboratory tests, Cation exchange, Soil properties, Soil tests.
Soil investigations.
Base saturation is such an important criterion for classifying soils in the U.S.
Soil Taxonomy that a procedure has been developed for scantily equipped field
laboratories. Exchange acidity and cation-exchange capacity (CEC) are determined
in sequence with the same samples. The procedure involves (i) displacement of
exchangeable hydrogen and Al with BaC12-triethanolamine solution and back-titra-
tion with HC1 to determine the exchange acidity, (ii) saturation with Al from
A1C13 solution, (iii) removal of excess Al with water, (iv) displacement of Al
with BaC12-triethanolamine solution and back-titration with HC1 to determine the
exchange capacity, and (v) estimation of basic cations by the difference between
the CEC and the exchange acidity. This is an extension of a well-established
procedure for determining exchange acidity. The CEC results compare closely with
the sums of cations for acid subsoils, but are low for Al horizons with much
organic matter.
76:07B-009
DETERMINATION OF THE HYDRAULIC CONDUCTIVITY - DRAINABLE POROSITY RATIO FROM
WATER TABLE MEASUREMENTS,
Skaggs, R.W.
North Carolina State University, Department of Biological and Agricultural
Engineering, Raleigh, North Carolina.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 1,
p 73-84, January-February 1976. 13 fig, 25 ref.
(See 76:02F-005)
236
-------
76:076-010
A TECHNIQUE TO DETERMINE IRON EFFICIENCY IN PLANTS,
Brown, J.C., and Jones, W.E.
United States Department of Agriculture, Agricultural Research Service, Plant
Stress Laboratory, Beltsville, Maryland.
Soil Science Society of America Journal, Vol. 40, No. 3 p 398-405 May-June
1976. 6 fig, 3 tab, 16 ref. '
Descriptors: Iron, Crop response, Fertilization, Soil tests, Soil investigations,
Nutrients, Crop production.
Soil tests should predict crop response to fertilization. In the case of Fe,
plant factors seem to affect the use of Fe by the plant; thus, soil tests may
not be reliable. Use of soil Fe by plants is genetically controlled by an adap-
tive mechanism which is activated in Fe-efficient plants in response toFe-stress,
but remains inactive if Fe is sufficient. Fe-inefficient plants develop less
Fe-stress response than Fe-efficient plants. Using this range of Fe-stress
response in plants as a basis, we developed a technique to screen plants for Fe
efficiency. A limited supply of Fe and some control using nutrient solutions,
N only as N03,- and N as NH4 and N03, and by varying the CaC03 and P concentra-
tions in the solutions. The optimum supply of Fe (0.2 mg Fe/liter) was deter-
mined by growing the plants at different Fe concentrations.
76:07B-011
LINE SOURCE SPRINKLER FOR CONTINUOUS VARIABLE IRRIGATION-CROP PRODUCTION STUDIES,
Hanks, R.J., Keller, J. , Rasmussen, V.P., and Wilson, G.D.
Utah State University, Department of Soil Science, Logan, Utah.
Soil Science Society of America Journal, Vol. 40, No. 3, p 426-429, May-June
1976. 3 fig, 2 tab, 4 ref.
Descriptors: *Sprinkler irrigation, Irrigation, Irrigation systems, Irrigation
effects. Crop production. Crop response, Fertilization.
The design details and a sample set of field test results for a line source
sprinkler plot irrigation system are presented. The system produces a water
application pattern which is uniform along the length of the plot and continu-
ously, but uniformly variable across the plot. By applying a fertility variable
along a plot (at right angles to the water variable) planted in some test crop,
the system offers a convenient means for developing crop production function
data. The system test area and water supply are both small. However, the
application of the system may be limited by wind and all water application lev-
els within a plot must be supplied at the same irrigation frequency.
76:-7B-012
SOIL SOLUTION CONCENTRATIONS: EFFECT OF EXTRACTION TIME USING POROUS CERAMIC
CUPS UNDER CONSTANT TENSION,
Severson, R.C., and Grigal, D.F.
United States Geological Survey, Department of Soil Science, Denver, Colorado.
Water Resources Bulletin, Vol. 12, No. 6, p 1161-1170, December 1976. 4 fig,
2 tab, 12 ref.
Descriptors: Soil water. Potassium, Calcium, Phosphorus, Moisture tension,
Soil moisture, Lysimeters, Soil investigations. Laboratory studies.
Proous ceramic cups under constant tension (0.45 bar) were used to extract
solutions from undisturbed soil columns. Solution concentration changed with
length of extraction time. Significant relationships were found between
extraction time and concentrations of P, Ca, and K in soil solution for two
sample depths in an Omega loamy sand soil column. At two extraction time
classes and at two sample depths, combined data from 12 soil columns
representing two soil series reinforce the relationship. As time to extract a
sample increases, the sample probably represents solution held by soil at
tensions approaching those applied to the ceramic cup. We recommend that the
choice of an extraction tension be given consideration in studies using porous
ceramic cups under constant tension for monitoring constituents of soil solution.
In addition, care must be taken to attain good physical contact between the cups
and the soil material.
237
-------
76:078-013
EVALUATION OF RESITANCE AND MASS TRANSPORT EVAPOTRANSPIRATION MODELS REQUIRING
CANOPY TEMPERATURE DATA,
Blad, B.L., and Rosenberg, N.J.
Nebraska University, Institute of Agriculture and Natural Resources,
Agricultural Meteorology Section, Department of Agricultural Engineering,
Lincoln, Nebraska.
Agronomy Journal, Vol. 68, No. 5, p 764-769, September-October 1976. 9 fig,
19 ref.
Descriptors: Alfalfa, Satellites, Canopy, Temperature, Evapotranspiration,
Hydrology, Water management, Model studies. Subsurface irrigation. Remote
sensing, Advection.
The increasing use of thermal scanners on aircraft and satellites makes it likely
that data on surface temperature for large areas will become routinely available.
If reliable evapotranspiration methods which incorporate surface temperature data
can be developed, an important tool for research and application in hydrology, in
irrigation scheduling, and in other water management procedures will result. A
'resistance model' which stems from the work of Brown and Rosenberg and a mass
transport (Daltonian) model for estimating evapotranspiration (ET) were tested on
large fields of naturally subirrigated alfalfa. Both models make use of crop
canopy temperature data. Temperature data were obtained with an IR thermometer
and with leaf thermocouples. A Bowen ratio-energy balance (BREB) model,
adjusted to account for underestimation of ET during periods of strong sensible
heat advection, was used as the standard against which the resistance and mass
transport model did not agree quite as well. Performance was good on clear and
cloudy days and also during periods of nonadvection of sensible heat. The
performance of the mass transport and resistance models was less satisfactory
for estimation of fluxes of latent heat for short term (15 min) periods. Both
models tended to overestimate at low LE fluxes.
76:07B-014
PERFORMANCE OF THE SILVER-PSYCHROMETER FOR MEASURING LEAF WATER POTENTIAL IN
SITU,
Hoffman, G.J., and Hall., A.E.
Western Region, Agricultural Research Service, United States Department of
Agriculture, P.O. Box 672, Riverside, California 92502
Agronomy Journal, Vol. 68, No. 6, p 872-875, November-December 1976. 4 fig,
17 ref.
Descriptors: Moisture stress, Temperature, Humidity, Radiation, Soil moisture,
Soil water.
Continuous in situ measurements of leaf water potential are often needed in
studies of the soil-plant-atmosphere continuum. The development of the silver-
foil thermocouple psychrometer has made these measurements possible. The
objective of the investigation was to evaluate the performance of the silver-
foil psychrometer under various steady-state and dynamic conditions. Leaf water
potential measurements were made in situ on pinto bean in a controlled environ-
ment plant chamber where temperature, relative humidity, CO2 concentration,
radiation, and photoperiod were precisely controlled. Typically, the psychrometer
will reach equilibrium with an intact leaf 2 hours after attachment. Consistent
leaf water potentials are attainable when the leaf temperature varies by as much
as 0.25 C/min. This thermal stability is as good as that of any multijunction
psychrometer described to date. At radiation levels below 50 Wm(-2), leaf water
potential readings can be made on unshaded leaves; above this level, the leaf
must be shaded to prevent thermal gradients across the leaf and psychrometer.
The silver foil psychrometer responded to rapid oscillations in leaf water
potential. During oscillations, leaf water potential preceded leaf conductance
and transpiration by one-third of the oscillation period. Net photosynthesis
oscillated in phase with leaf conductance, indicating that net photosynthesis
is limited by the internal C02 concentration, even at very low irradiances.
238
-------
76:07B-015
SAMPLING THE UNSATURATED ZONE IN IRRIGATED FIELD PLOTS,
Pratt, P.P., Warneke, J.E., and Nash, P. A.
California University, Department of Soil Science, Riverside, California 92502.
ce?Cu S°cie^ of America Journal, Vol. 40, No. 2, p 277-279, March-April
• 6 tclfo f I 3TSZ .
Descriptors: Nitrate, Chloride, Drainage water. Salinity, Electrical conductance,
Farm waste. Soils, Soil investigations, Irrigation, Irrigation effects, Sampling.
Data obtained from samples from each of 10 holes/plot for one plot from each of
three soils were subjected to statistical analysis and used to formulate plans
for sampling the 1.5- to 4 . 5-cm depth of 48 experimental plots that had received
animal manures. The statistical analysis of these three plots suggested that 10
holes/plot and 10 samples/hole woulc provide plot means within about 20 percent
of the true means for nitrate and chloride concentrations and electrical
conductivity of saturation extracts, except for one soil which had residual salts
in highly variable concentrations at the 3.0- to 4. 5-cm depth. The sampling
procedure developed gave satisfactory results when statistical analysis of the
effects of manure treatments, soils and irrigation levels on nitrate, chloride
and EC(e) were measured.
76:076-016
EXTENDED FIELD USE OF SCREEN-COVERED THERMOCOUPLE PSYCHROMETERS ,
Brown, R.W. and Johnston, R.S.
United States Department of Agriculture Forest Service, Intermountain Forest and
Range Experiment Station, Ogden, Utah 84401
Agronomy Journal, Vol. 68, No. 6, p 995-996, November-December 1976. 1 fig, 1 tab,
7 ref.
Descriptors: Soil water. Soil moisture. Data collection.
The use of screen-covered thermocouple psychrometers for insitu measurements of
soil water potential has been criticized because of possible soil and micro-
organism contamination through the screen covering. Double- junction Peltier
psychrometers with a screen covering were installed in the soil under field con-
ditions for periods ranging from 2 to 40 months of continuous exposure, and were
then removed and examined for evidence of loss of calibration sensitivity and
contamination by soil particles and micro-organisms. The uncleaned psychrometers
were recalibrated in the laboratory and then disassembled and examined under a
microscope (250 times) for contamination. Although slightly more than half of
the units lost some sensitivity after field exposure, the average decrease was
less than 5%. The psychrometer cavities were all nearly free of soil particles,
the thermocouple junctions were shiny, and no evidence of microbial attack was
evident. It appears that long-term field exposure of screen-covered psychrometers
is no more detrimental to their performance than that of ceramic or other psychrom-
eters.
76:07B-017
ALGORITHM FOR SOLAR RADIATION ON MOUNTAIN SLOPES,
Swift, L.W. Jr.
United States Department of Agriculture, Coweeta Hydrologic Laboratory, South-
eastern Forest Experiment Station, Forest Service, Franklin, North Carolina 28734
Water Resources Research, Vol. 12, No. 1, p 108-112, February 1976. 2 fig, 1 tab,
17 ref.
Descriptors: Algorithms, Solar radiation, Computer models. Model studies, Mountains.
A generalized algorithm provides the daily total of potential solar radiation on
any sloping surface at any latitude. The algorithm can be coded as subroutines
of a computer model that requires solar radiation as a variable. The required
inputs are Julian dates and the latitude, inclination, and aspect of the slope.
In addition to computing potential solar radiation, the routine provides estimates
of actual radiation on any slope on the basis of measured solar radiation for a
nearby horizontal surface that has the same cloud cover.
239
-------
76:07B-018
MEW TECHNIQUE FOR MEASURING THE WATER POTENTIAL OF DETACHED LEAF SAMPLES,
United States Department of Agriculture Forest Service, Intermountain Forest
and Range Experiment Station, Ogden, Utah 84401
Agronomy Journal, Vol. 68, No. 2, p 432-434, March-April 1976. 4 fig, 7 ref.
Descriptors: Evaporation, Sampling, Leaves.
Evaporative losses and contamination in sample disks after they are cut from plant
leaves often cause errors in measurements of water potential. A new technique for
collecting detached leaf disks to measure water potential eliminates most of the
errors associated with other methods. The leaf cutter, contains a double-junction
Peltier thermocouple psychometer. When a leaf disk is removed from the plant,
it can be sealed immediately against the cavity containing the psychometer.
76:078-019
EVALUATION OF AN ELECTRONIC FOLIOMETER TO MEASURE LEAF AREA IN CORN AND SOYBEANS,
Hatfield, J.L., Stanley, C.D., and Carlson, R.E.
California University, Atmospheric Sciences Section, Department of Land, Air, and
Water Resources, Davis, California 95616
Agronomy Journal, Vol. 68, No. 2, p 434-436, March-April 1976. 2 fig, 1 tab, 5 ref.
Descriptors: Corn, Soybeans, Measurement.
Known areas were measured with an electronic foliometer to determine the errors
involved with this instrument. Good agreement between measured and known areas
was found and there was high accuracy and precision for both the conveyor belt
and sheath method. Thests were made comparing the foliometer, a planimeter, and
maximum length times maximum width (LW) for soybeans and comparing foliometer and
LW for corn. There was close agreement between planimeter and foliometer measure-
ments for soybeans (r = 0.99). The foliometer compared favorably with LW for corn
(r = 0.96). Coefficients for converting LW measurements to leaf areas were deter-
mined for soybeans and three corn hybrids.
76:07B-020
SIMULATION MODEL FOR NUTRIENT UPTAKE FROM SOIL BY A GROWING PLANT ROOT SYSTEM,
Caassen, N. and Barber, S.A.
Agronomy, Fusagri, Cagua, Venezuela.
Agronomy Journal, Vol. 68, No. 6, p 961-964, November-December 1976. 1 fig, 1 tab,
13 ref.
Descriptors: Simulation analysis, Mathematical models, Model studies, Nutrients,
Computer programs, Corn, Potassium, Diffusion.
Mathematical models of nutrient uptake by plants are useful for investigating the
effect of various soil and plant factors on nutrient flux to plant roots. The
objective of this research was to develop a model based on theoretical consider-
ations of the processes of nutrient uptake by plant roots growing in soil and then
to test the model experimentally. The soil and plant factors used in the model
were to be measured independent of final nutrient uptake. The model for flux by
mass flow and diffusion to the root was patterned after that of Nye and Marriott.
The absorption kinetics of the root were assumed to follow Michaelis-Menten kin-
etics. The Nye-Marriott model gives the nutrient concentration at the root with
time. From this accumulated uptake per sq cm of root surface with time was cal-
culated. Rate of root growth was assumed exponential for the growth of the young
plant. Uptake per sq cm of root with time was combined mathematically with rate
of root growth to get total uptake with time by the plant. The present program
assumes root hairs do not affect uptake and that roots do not compete for nutrients.
76:07B-021
A SYSTEM AND PROGRAM FOR MONITORING C02 CONCENTRATION, GRADIENT, AND FLUX IN AN
AGRICULTURAL REGION,
Rosenberg, N.J. and Verma, S.B.
240
-------
Nebraska University, Institute of Agriculture and Natural Resources, Department
06 Agricultural Engineering, Lincoln, Nebraska 68583
Agronomy Journal, Vol. 68, No. 2, - 414-418, March-April 1976. 3 fig, 6 ref.
Descriptors: Photosynthesis, Carbon dioxide, Nebraska, Sampling, Wind speed,
Air temperature. Data collections.
Because of the changing global concentration of carbon dioxide and the possible
effects of thas change on photosynthetic activity worldwide, a program has been
developed for monitoring atmospheric carbon dioxide concentration and gradients
representative of a large agricultural region. The program is carried out at
Mead, Nebraska. A meteorological tower is equipped with sampling intakes at
various elevations up to 16 m, through which air is drawn to the laboratory for
analysis with infra-red gas analyzers. An automatic calibration system has been
developed to permit hourly checks of analyzer performance. Profiles of wind
speed and air temperature are also measured. The equipment, the calibration tech-
niques, and the errors associated with the measurements of C02 concentration and
gradients are described. Some initial observations of C02 concentrations and
fluxes are presented.
76:07B-022
THE CONCENTRATION OF DISSOLVED SOLIDS AND RIVER FLOW,
O'Connor, D.J.
Manhattan College, Department of Civil Engineering, Bronx, New York 10471
Water Resources Research, Vol. 12, No. 2, p 279-294, April 1976. 15 fig, 2 tab,
18 ref.
Descriptors: Dissolved solids, River flow. Rivers, Return flow.
A general expression ^for the spatial and temperal distribution of conservative
dissolved solids in freshwater rivers which incorporates the contribution of both
the groundwater and surface water components of river flow is presented. The
first part of this paper deals with the steady state conditions. With certain
simplifying assumptions the correlation between concentration of dissolved solids
and flow is developed for both spatially uniform and nonuniform conditions. The
analysis includes the effect of both geophysical discontinuities and point sources.
Examples from a number of rivers throughout the country are presented to indicate
the utility of the analysis. The second part addresses the temporal variation of
the dissolved solids concentration for two time scales. One describes the annual
variation in concentration due to the time variable components of the river flow,
and the second the variation over a semimonthly period due to a time variable
point input. Applications to a variety of river conditions are also presented
for the time variable analysis.
76:07B-023
AN AUTOMATIC SYSTEM FOR MEASURING SALT CONCENTRATION PROFILES IN POROUS MEDIA,
Barnes, P.L., Smajstrla, A., and Reddell, D.L.
Texas A and M University, Department of Agricultural Engineering, College Station,
Texas
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, 14 p, December 14-17, 1976, Chicago, Illinois. 5 fig, 2 equ, 9 ref.
Descriptors: Salinity, Soil salinity, Saline soils.
The construction of a low-cost salinity sensor is described which is easily con-
structed Also, an electronic circuit which automatically reads and records field
and laboratory data from multiple salinity sensors is presented. With this sys-
tem, salinity data can be collected from several hundred sensors in a short time
period. This information can be used to predict and manage real land potential
pollution movements in soils.
POLLUTION PROBABILITY ESTIMATED BY SMALL STORM FREQUENCY,
Lewis, R.B., Huaser, V.L., Menzel, R.G., and Ross, J.D.
Texas Tech University, Department of Agricultural Engineering, Lubbock, Texas.
241
-------
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, 23 p, December 14-17, 1976, Chicago, Illinois. 10 fig, 4 tab, 10 ref.
Descriptors: Surface runoff, Runoff, Return flow, Water quality. Water quality
management, Hydrologic data, Hydrologic aspects, Nebraska, Corn, Crop production.
The concentration of chemicals in surface runoff water is often an important con-
sideration. Water soluble chemicals which are applied to the surface of plants
or soil may appear in the highest concentration in runoff water from small storms.
Because of this, some aspects of water quality management require quite different
hydrologic information than has been required to solve problems considered in
the past. This study of small storms in the central Great Plains near Hastings,
Nebraska, revealed much about small storms and their relation to water quality.
Contour cultivation of corn substantially decreased the number of runoff events
resulting from small storms, and thus substantially decreased the likelihood of
pollution from surface applied chemicals. Our finding agrees with past concepts,
like the large decrease in annual runoff from corn which results from contour
tillage. However, contour tillage of small grains (wheat and oats) did not cause
a corresponding decrease in the number of runoff events from small storms. This
finding conflicts with annual runoff data that shows a decrease in runoff from
contour tillage of small grains.
76:07B-025
A MODEL TO PREDICT TOTAL ENERGY REQUIREMENTS AND ECONOMIC COSTS OF IRRIGATION
SYSTEMS,
Chen, K-K,m Wensink, R.B., and Wolfe, J.W.
Oregon State University, Department of Agricultural Engineering, Corvallis, Oregon.
Presented at the 1976 Winter Meeting of the American Society of Agricultural
Engineers, 23 p, December 14-17, 1976, Chicago, Illinois. 11 fig, 4 tab, 4 ref.
Descriptors: Computer models, Model studies, Simulation analysis, Economics,
Irrigation, Irrigation systems, Sprinkler irrigation, Surface irrigation, Energy.
A computer model has been developed to simulate total fossil energy requirements
and economic costs for hand move, side roll, solid set, permanent, center pivot,
drip and surface systems. In addition to evaluating a specific design, the
analyst can direct the program to search for minimum economic and/or minimum energy
designs for a specific system. The moedl was used to determine the effects of
static pumping lifts on minimum energy and minimum economic designs. The fossil
energy utilization hierarchy was shown to be a function of pumping lifts, with
the surface system the most efficient at zero-foot lift and the least efficient
at pumping lifts above a few hundred feet. The economic hierarchy was also a
function of pumping lifts. However,- drip produced the lowest annual per acre cost
at all pumping depths. The difference in annual fossil energy requirements and
economic cost between energy and economic designs were relatively small. However,
initial investment costs of the energy designs averaged 11.6 percent larger than
the economic designs. Although economic designs annually consumed an average of
76 kilowatt-hours more electric energy than energy designs, energy designs annual-
ly cost 7.24 dollars per acre more. '
76:078-026
SOIL SALINITY TESTING IN THE FIELD,
Irrigation Journal, Vol. 26, No. 1, p 14-15, January-February 1976. 3 fig.
Descriptors: Salinity, Saline soil, Electrical conductance, Electrodes.
One of the more important chores of an agricultural water manager treating saline
soils is getting accurate information of the concentration and extent of soluble
salts in such soils. Eyeballing crops and soils in such areas is not enough
since salinity may reduce crop yields by as much as 25 percent without visible
symptoms. U.S. Department of Agriculture at the Agricultural Research Service's
Salinity Laboratory in Riverside, California, has developed two devices that
could make life easier for those charged with keeping salinity down to manage-
able levels. The devices may one day play a part in reducing or preventing farm
income losses from salinity as well as aid in preventing environmental pollution.
242
-------
76:076-027
INFORMATION STORAGE AND RETRIEVAL FOR EVALUATION OF IRRIGATION POTENTIAL,
Rochester, E.W., McGuire, J.A., and Stallings, J.L.
Auburn University, Agricultural Experiment Station, Auburn, Alabama 36830
Paper No. 76-2035, Presented at the Annual Meeting of the American Society of
Civil Engineers, June 27-30, 1976, Lincoln, Nebraska, 3 fig, 5 ref.
Descriptors: Computers, Information retrieval, Alabama, Crop production. Soils,
Climate, Irrigation.
A computerized information storage and retrieval system is being developed in Ala-
bama. The system called ARIS, is based on commercially available software and
makes available numerical data about the resources of the State. Included in the
utilization of ARIS is the evaluation of irrigation potential. Data describing
soils, climate, water and crops are being encoded for this evaluation.
76:078-028
MAP OF SALTY SOILS OF AFRICA,
Aubert, G.
Office de la Recherche Scientifique et Technique Outre-Mer, Bondy, France.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 598-604. 22 ref.
Descriptors: Salinity, Saline soils, Salts, Africa, Mapping, Maps.
This map is presented as part of the ISSS-UNESCO Project, in cooperation with the
desertification map project of FAO and UNEP- It has been compiled with the assis-
tance of S.A. Radwanski and G. Murdoch of the Land Resources Division of the United
Kingdom, numerous directors of soils programs in African countries, J. Riquier of
FAO, and pedologists of ORSTOM.
76:07B-029
BASIC PRINCIPLES FOR PROGNOSIS AND MONITORING OF SALINITY AND SODICITY,
Massoud, F.I.
Food and Agriculture Organization, Soil Resources Development and Conservation
Service, Land and Water Development Division, Rome.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 432-454. 67 ref.
Descriptors: Salinity, Sodium, Saline soils, Sampling, Salt balance, Salts, Drain-
age, Evapotranspiration, Irrigation water, Groundwater.
The development of a standardized methodology for prognosis and monitoring of salin-
ity and sodicity for application throughout the world may not be easily achieved
or appropriate practically where conditions vary from one location to another as
is the case in salt affected soils. Moreover, there is usually an element of risk
in attempting to transfer the procedures and to over-generalize the use of an
established standard methodology without giving enough consideration to local
changes or needs. The common tendency to adopt rather than to adapt a methodology
quite often gives misleading results and it would be more fruitful and, in this
case essential, to go through the rigors of applying the principles. Therefore,
knowledge of the basic principles discussed in this paper is an indispensible
requirement for the development of local procedures or the adoption of an estab-
lished methodology.
76:07B-030
SALINITY SURVEY IN ISRAEL,
Boaz, M., Husenberg, I., and Posin, Y.
Irrigation and Soil Field Service, Ministry of Agriculture, Tel-Aviv. Israel.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 388-399. 3 fig, 4 tab.
Descriptors: Salinity, Surface, Electrical conductance, Saline water, Chlorides,
Dissolved solids, Orchards, Crop production, Crop response.
243
-------
The Salinity Survey was initiated in the Spring of 1963, a year before the oper-
ation of the National Water Carrier, which conducts water from Lake Tiberias in
the North, to the Southern parts of the Country- The electrical conductivity (EC)
of the lake water at that time was 1.5 millimhos/cm, with a chloride content of
about 350 ppm and about 1000 ppm total dissolved salts (TDS). The salinity of
the lake water at the present time is considerably lower: EC approximately 1.2
mmhos/cm; Cl approximately 250 ppm; TDS approximately 850 ppm. It was feared that
the water would be too saline for the irrigation of sensitive crops like citrus,
which is the country's main agricultural export.
244
-------
SECTION XXXVII
RESOURCES DATA
EVALUATION, PROCESSING AND PUBLICATION (GROUP 07C)
76:07C-001
A SIMPLE COMPUTER PROGRAM FOR THE DETERMINATION OF AQUIFER CHARACTERISTICS FROM
PUMP TEST DATA,
Holzschuh, J.C., III.
Southwest Florida Water Management District, Brooksville, Florida
Ground Water, Vol. 14, No. 5, p 283-285, September-October 1976. '3 fig, 1 tab,
2 ref.
Descriptors: "Computer programs', *Data processing, *Aquifer characteristics,
*Pump testing. Estimating, Analytical techniques, Graphical methods. Graphical
analysis, Leakage, Transmissivity, Storage coefficient, Hydraulic conductivity.
A computer program, based on the Hantush inflection method and designed for
"desk top" computers was presented. The method assumed a leaky, isotropic,
homogeneous aquifer of infinite areal extent. The language employed was BASIC,
and interactive language used on the Wang Model 2200 programmable calculator.
The program can be easily adapted to FORTRAN IV for use on larger machines.
76:07C-002
CONVERSION' OF IRREGULAR FINITE ELEMENT GRID DATA TO REGULAR GRID FOR THREE-
DIMENSIONAL COMPUTER PLOTTING,
Gupta, S.K., Morrissey, M.W., Lonczak, J. , and Tanji, K.K.
California University, Department of Land, Air, and Water Resources, Water Science
and Engineering Section, Davis, California 95616
Water Resources Research, Vol. 12, No. 4, p 809-811, August 1976. 3 fig, 4 ref.
Descriptors: Finite element analysis. Computers, Computer models, Computer
programs.
Three-dimensional plotting provides a useful means for the illustration and inter-
pretation of results from finite element simulation. The computer graphic pack-
ages usually available at computer center, however, require data on regular grids
and thus are not adaptable to isoparametric finite elements, which are combin-
ations of various shapes and sizes of trapezoids. By using the basic functions,
a method is presented for the estimation of regular grid values from irregular
gridded data for plotting purposes.
76:07C-003
SALINE WATER CLASSIFICATION IN IRAN BY RATIONAL METHODS,
Massoumi, A.M.
Tehran University, College of Agriculture, Department of Soil Science, Karadj,
Iran.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p -455-465. 4 fig, 3 tab, 4 ref.
Descriptors: Saline water, Salinity, Irrigation efficiency, Irrigation, Irriga-
tion water.
The classification of saline water is very important for irrigation projects in
Iran. The application of U.S.S.L. method has not given a good result in this
country. Therefore, it was decided to examine the rational method which is based
on plant resistance against the salinity, the texture of soils, and irrigation_
efficiency. For a given plant, growth in a. given soil, the quality of irrigation
water depends only on the efficiency of irrigation.
76:07C-004
FIELD TESTING OF A NEW SYSTEM FOR QUALIFYING IRRIGATION WATER,
Sentis, I.P., and Dappo, F.
245
-------
Institute de Edafologia, Universidad Central de Venezuela, Maracay, Venezuela.
Proceedings of the International Salinity Conference, Texas Tech University,
Lubbock, Texas, August 16-20, 1976, p 376-387. 1 fig, 5 tab, 14 ref.
Descriptors: Irrigation water, Salinity, Salts, Saline soil, Salt balance, Leaching,
Calcium, Magnesium, Drainage, Crop production, Sodium.
A new system for evaluating irrigation waters in relation to the potential problems
of salinity and sodicity is tested under five different situations of salt affected
soils in Venezuela. The system is based on an independent balance of the different
ions in soil solution in relation to the effective leaching and limiting solubilities
of Ca sulfates and Ca plus Mg carbonates. Qualification is based not only on the
concentration and composition of salts in irrigation water but on the drainage condi-
tions of the soil profile and on the crop tolerance.
246
-------
SECTION XXXVIII
ENGINEERING WORKS
HYDRAULICS (GROUP 08B)
76:088-001
SEGMENTAL ORIFICES WITH SHUNT METERS TO TOTALIZE PIPELINE FLOW
Kruse, E.G., and Young, D.A.
Agricultural Research Service, Fort Collins, Colorado
rsgineers- vo1- 19- No-
Descriptors: *Pipe flow, *Flow rates, *Measurement, *Irrigation engineering
instrumentation, Calibrations, Laboratory tests, Orifices, DischargI (Water)
Discharge measurement, Flowmeters, *Flow measurement, On-site tests.
Four segmental orifice plates were constructed and evaluated for use with
domestic water meters in shunt lines for totalizing irrigation flow. Total
pipe flow was related to shunt- line flow in the laboratory; then two field
installations in self-propelled, center-pivot sprinklers were evaluated for
two seasons. After two years of field evaluations, an accuracy of plus or
minus 8% of true flow was noted, which is suitable for use in determining
groundwater draft by irrigation wells.
76:08B-002
A THEORY OF FLOW RESISTANCE FOR VEGETATED CHANNELS,
Thompson, G.T., and Roberson, J.A.
Washington State University, Department of Civil and Environmental Engineering,
Pullman, Washington.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 2,
p 288-293, March-April 1976. 5 fig, 12 ref.
(See 76:04A-003)
76:08B-003
BAYESIAN APPROACH TO TILE DRAIN DESIGN,
Musy, A., and Duckstein, L.
Ecole Polytechnique Federale de Lausanne, Department of Agriculture, Switzerland.
Journal of the American Society of Civil Engineers, Vol. 102, No. IR3, p 317-334,
September 1976. 7 fig, 3 tab, 30 ref.
Descriptors: *Tile drainage, *Land reclamation, *Decision making, Agricultural
engineering, Design, Water management (Applied), Hydrology, Equations, Economics,
Costs, Systems analysis, Methodology, Crops, Evaluation, Optimization, *Tile
drains. Risks.
Economic and sociopolitical aspects of land reclamation in areas that neces-
sitate drainage are combined with technical problems to yield a set of possible
decisions, among which an optimum design is chosen. The loss or objective
function is the sum of the expected damage caused by the submersion of given
crops resulting from extreme rainfall events, and the initial cost of the
reclamation. When the parameter uncertainty in the probability distribution
function of extreme events is taken into account in the loss function, a Bayes
risk function is obtained. The Bayes decision theoretic (BDT) approach consists
of seeking a decision that minimizes the Bayes risk function. The BDT also
evaluates the decision taken and compares the expected cost of delaying, the
construction to the worth of additional information resulting from such a delay.
The practical example of an intensive agricultural system with different types
of soils and crops illustrates the methodology. Crop loss functions and prob-
ability distributions of events are assumed on the basis of empirical observa-
tions.
247
-------
76:088-004
TEMPERATURE EFFECTS ON EMITTER DISCHARGE RATES,
Parchomchuk, P-
Agriculture Canada, Research Station, Summerland, British Columbia, Canada.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 690-692, Special Edition 1976. 5 fig, 1 tab, 4 ref.
Descriptors: *Temperature, *Water temperature, *Viscosity, Flow rates,
Uniformity coefficient, Hydraulics, Irrigation, Irrigation systems.
One of the major requirements of trickle irrigation is precise control of water
application rate. To attain optimum control, all emitters must deliver water at
equal rates and rates should not change with time or environmental factors.
There is general agreement that discharge rates should not vary more than +10
percent for uniform water application. Variations in emitter manufacture or
operating pressure are cited as the major sources of emitter discharge variation
(Keller and Karmeli, 1974). However, an additional factor which could result in
large emitter discharge variations is water temperature variation. Viscosity
changes, due to changing water temperatures, cause emitter discharge variations
greater than the maximum +10 percent limit if flow through the emitter is
laminar. Turbulent flow emitters, on the other hand, are not affected by
viscosity changes. Water temperature variations can occur in a number of ways.
Temperature variation occurs over a period of time with day-night, day to day
and seasonal weather changes and from end to end of lateral lines due to solar
heating of black plastic pipe. Water temperatures in lateral lines as high as
77°C (170°F) have been reported. This study investigates the effect of water
temperature variation upon discharge rates of several emitter types. Water
temperature variation in lateral lines was measured to determine expected
discharge variations.
76:08B-005
TRANSVERSE MIXING IN NATURAL CHANNELS,
Yotsukura, N. and Sayre, W.W.
United States Geological Survey, National Center 430, Reston, Virginia 22092
Water Resources Research, Vol. 12, No. 4, p 695-704, August 1976. 8 fig, 25 ref.
Descriptors: Mathematical models. Model studies, Channel flow. Channels, Mixing,
Simulation analysis.
A mathematical model is presented for predicting the steady state two-dimensional
distribution of solute concentration in a meandering nonuniform natural channel.
Two features of the convection-diffusion (mixing) equation derived herein are that
it employs the transverse cumulative discharge as an independent variable replac-
ing the transverse distance and that it is developed in an orthogonal curvilinear
(natural) coordinate system which follows the general direction of the channel
flow. With the help of the continuity equation of water the transverse convec-
tion term which cannot be neglected in a natural channel is eliminated from the
mixing equation by a transformation wherein cumulative discharge replaces trans-
verse distance. Introduction of scalar diffusivity coefficients into the mixing
equation is found to be more justifiable in the natural coordinate system than
in a rectangular Cartesian coordinate system. The transformed mixing equation
unifies and generalizes essential concepts of several existing models which have
been used successfully for simulating steady state transverse mixing in irregular
natural channels. Solution methods, both analytical and numerical, and parameter
estimation methods are presented, after which some results of simulation are
compared with observed data.
76:08B-006
HYDRAULIC CHARACTERISTICS OF IRRIGATION FURROWS,
Ramsey, M.K. and Fangmeier, D.D.
Arizona University, Department of Soils, Water, and Engineering, Tucson, Arizona.
Paper No. 76-2046, Presented at the Annual Meeting of the American Society of
Civil Engineers, June 27-30, 1976, Lincoln, Nebraska, 17 p, 4 fig, 5 ref.
Descriptors: Infiltration, Furrow irrigation. Furrows, Furrow systems, Irrigation
systems. Irrigation effects, Hydraulics.
248
-------
Seven irrigations were conducted on a precision field furrow. Inflow, outflow,
water surface elevations, soil surface elevations, and furrow geometry were
measured. Methods of determination and comparisons of infiltration functions,
effect of flow depth on intake, and flow resistance parameters are presented.
76:08B-007
ENERGY ECONOMICS IN PIPE AND SYSTEM SELECTION,
Keller, J.
Utah State University, Department of Agricultural and Irrigation Engineering, Logan,
Utah.
1976 Annual Technical Conference Proceedings, Sprinkler Irrigation Association,
Technology for a Changing World, February 22-24, 1976, Kansas City, Missouri,
p 134-145, 4 fig, 2 tab, 6 ref.
Descriptors: Energy, Irrigation design, Hydraulics, Irrigation systems, Pipe flow,
Pipes, Irrigation efficiency, Hydraulic design.
A rational means for using economic factors as the basis for selection of pipe and
irrigation system components is presented. A graphical method developed by Keller
(3) is also presented which can be used to speed the economic sizing of mainline
pipes.
76:08B-008
VENTURI FLUMES FOR CIRCULAR CHANNELS,
Diskin, M.H.
Arizona University, Department of Hydrology and Water Resources, Tucson, Arizona
Journal of the Irrigation and Drainage Division, Vol. 102, No. IR3, p 383-387,
September 1976. 4 fig, 1 tab, 6 ref.
Descriptors: Flumes, Flow measure, Flow rates, Venturi flumes, Open channels.
The principle of operation and the advantages of Venturi flumes for open-channel
flow measurements are well known and amply documented in technical literature
dealing with flow measuring methods. The main advantages are the ability to adapt
the shape of the flume to the shape of the channel and to the range of flows expect-
ed, the possibility of predicting the coefficients of discharge either by theor-
etical considerations or from results of calibration tests, and finally the rela-
tively small head losses possible with Venturi flumes as evident by the high values
of allowable submergence. The purpose of this paper is to present some experimental
results for Venturi flumes. While these designs may be used also as Venturimeters
for full pipe flow, the results given herein refer only to open-channel flow at a
mild slope. The results are not applicable to steep channels where the flow is
supercritical and a jump forms a short distance upstream of the flume. Informa-
tion about the limiting submergence of the flumes tested is also presented.
249
-------
SECTION XXXIX
ENGINEERING WORKS
MATERIALS (GROUP 08G)
76:08G-001
SHUNT LINE METERING SYSTEM FOR IRRIGATION WELLS,
Hill, W.C., and Ruff, J.F.
Colorado State University, Department of Civil Engineering, Fort Collins, Colorado.
Transactions of the American Society of Agricultural Engineers, Vol. 19, No. 3,
p 494-500, May-June 1976. 15 fig, 2 tab, 5 ref.
Descriptors: *Flow measurement, *Wells, *Irrigation wells, *Orifices,
Calibrations, Laboratory tests, Equations, Mathematical studies, Instrumentation,
Measurement, Pipes.
The testing and development of a shunt line metering system with segmental
orifice were described. This type of metering system provides a low cost means
of cumulatively measuring the volume of water discharged from irrigation wells.
The flow through the shunt line, which was measured by a small household type
water meter, was related to the flow through the main irrigation pipe by a flow
coefficient which was experimentally determined for a 15.41 cm (6 in) pipe. This
flow coefficient is a function of the degree of orifice contraction. It was
pointed out that the field calibration of the meter was not necessary. The cost
of the metering system can be less than $100 and the accuracy was shown to be
within + or - 5 percent.
76:08G-002
FIELD EVALUATION OF 102-MM (4-INCH) CORRUGATED POLYTHYLENE TUBING,
McCandless, D.E., Jr.
United States Department of Agriculture, Soil Coaservation Service, Department of
Water Management Engineering, Broomall, Pennsylvania.
Transactions of the American Society of Agricultural Engineers, Soil and Water,
p 514-516, Special Edition 1976. 7 tab, 3 ref.
Descriptors: Drainage, Drainage engineering, Drainage practices.
A field evaluation of the physical condition of installed 102 mm (4 in.)
corrugated polyethylene tubing was made in four states in the northeast by the
United State Department of Agriculture Soil Conservation Service. Elongation and
deflection data were summarized on tubing from 54 sites. Deflections of 13 to 25
percent were typical, however, seven sites had deflections greater than 35 percent.
The tubing was elongated 4.2 percent on the average when installed with a wheel
trenching machine.
76:08G-003
COMPLEXES AFFECTING THE SOLUBILITY OF CALCIUM CARBONATE IN WATER - PHASE II,
Larson, T.E., Sollo, F.W., Jr., and McGuirk, F.F.
Illinois State Water Survey, Urbana, Illinois.
Illinois Water Resources Center, Urbana, Research Report No. 108, February 1976.
57 p, 17 tab, 39 ref. OWRT B-0820ILL(1). 14-31-0001-4078.
Descriptors: *Hardness (Water), *Scaling, *Corrosion, *Calcium carbonate,
Magnesium, Sodium, Potable water. Water quality, *Solubility, *Hydrogen ion
concentration. Volumetric analysis, Water supply.
Water utilities have a tremendous investment in the miles of pipe, valves, and
other appurtenances in water distribution systems. Failure to protect these
systems against corrosion and excessive scale formation could necessitate
replacement of the distribution systems at an estimated cost of $25 billion.
Calculation of the true equilibrium or saturation pH, pHs, for calcium carbonate
and adjustment of the water to that pH is essential to supply water of high
quality and to avoid corrosion and scale formation in these water distribution
systems. In some cases the actual pH must be from 0.6 to 1.0 unit above pHs,
250
-------
as determined from the calcium and alkalinity analyses. Certain complexes may be
responsible in part for this fact. The objective of this study was to evaluate
the dissociation constants of the complexes so that the optimum pH can be more
accurately calculated. A titration method was used to measure the effects of
complex formation on the pH of reaction mixtures and appropriate computer programs
were developed to calculate the dissociation constants. Experimental procedures
and results from the determination of dissociation constants for complexes of
magnesium, calcium and sodium with carbonate, bicarbonate, hydroxide, and sulfate
and a method to utilize these constants in calculating pHs in public water
supplies are discussed.
251
-------
SECTION XL
AUTHOR INDEX
Aarstad, J.S.
76:03F-071
Abdel Wahid, A.A.
76:03C-010
Abdul Khader, M.H.
76:02F-033
Abel, G.H.
76:03F-024
Abel, M.E.
76:03F-028
Adams, F.
76:02G-063
Adams, J.E.
76:03F-036
Adriano, D.C.
76:058-054
Aguado, E.
76:04B-001
Ahuja, L.R.
76:020-005
76:02G-014
76:020-024
76:020-049
Akins, M.B.
76:058-020
Alemi, M.H.
76:020-080
Aleti, A.
76:05B-051
Alexander, E.B.
76:078-008
Alexander, M.
76:020-020
76:020-068
Alfaro, J.F.
76:02E-012
76:03F-100
Allen, S.E.
76:021-004
Alley, W.M.
76:04B-001
Alpert, J.E.
76:050-002
Alzubaidi, A.H.
76:020-126
Amerman, C.R.
76:020-073
Amir, I.
76:03F-019
Anagnostopoulos, Tr.
76:05B-055
Anderson, O.E.
76:03F-073
Antie, D.A.
76:020-021
Ardakani, M.S.
76:020-052
76:05B-046
Arkin, G.F.
76:03F-036
Armstrong, J.M.
76:06A-003
Asmussen, L.E.
76:02E-002
76:058-047
Aubert, G.
76:07B-028
Avnimelech, Y.
76:020-047
Ayers, R. S.
76:05A-013
Aylmore, L.A.G.
76:020-110
Baert, L.
76:02K-017
Bahrani, B.
76:03F-051
Baker, F.G.
76:020-079
Baker, V.R.
76:02E-007
Banin, A.
76:03F-061
76:03F-062
Baradas, M.W.
76:020-007
Barber, S.A.
76:021-008
76:03F-014
76:03F-023
76:07B-020
Barfield, B.J.
76:02J-013
Bar-Josef, B.
76:03F-001
Barnes, P.L.
76:020-122
76:078-023
Bartlett, R.J.
76:021-002
76:0?K-005
76:02K-006
Basak, P.
76:02F-001
Bassett, D.L.
76:04A-OOS
Basu, U.
76:020-017
Bauer, A.
76:020-075
76:03F-084
Allen, D.M.
76:028-007
Allen, R.R.
76:04A-009
Babu, O.K.
76:020-085
76:020-094
76:020-095
76:020-100
76:020-101
Baumgartner, N.
76:020-001
Beale, O.W.
76:03F-033
252
-------
Beard, W.E.
76:02G-022
76:02G-053
Beauchamp, E.G.
76:021-006
Beck, B.
76:05B-042
Becker, L.
76:04A-004
Beese, F.
76:02G-003
Bellantouni, B.
76:02G-007
76:02G-008
Ben-David, A.
76:03F-019
Bennett, A.C.
76:02G-063
Bennett, F.W.
76:05B-051
Berndt, H.D.
76:02E-013
Bhattacharya, R.
76:026-010
76:02G-070
76:026-088
Biggar
76:02G-080
76:02G-084
Boersma, L.
76:050-004
Bogardi, I.
76:06A-005
Bollag, J.-M.
76:02G-044
Bolton, G.C.
76:02J-010
Bondietti, E.A.
76:026-103
Booram, C.V. Jr.
76:058-047
Booth, S.J.
76:048-007
Borchert, H.R.
76:02G-004
Boswell, F.C.
76:03F-057
76:03F-073
76:07B-002
Bottomley, A.
76:060-003
Bouldin, D.R.
76:056-009
76:058-011
Bouma, J.
76:02G-079
Bouwer, H.
76:02F-019
76:02G-087
Brinkley, F.S.
76:02G-103
Brinkman, W.L.F.
76:02E-004
Broadbent, F.E.
76:05B-014
Brock, R.R.
76:02F-025
Brown, J.C.
76:07B-010
Brown, K.W.
76:03F-055
76:05G-006
Brown, R.W.
76:07B-016
76:078-018
Bruce, R.R.
76:02G-013
Brutsaert, W.
76:020-013
76:02G-099
Bryan, W.E.
76:03F-069
'Bundgaard-Nielsen, M.
76:056-023
Buras, N.
76:04A-006
Burau, R.G.
76:03F-005
Bishop, S.E.
76:058-054
Bitzer, M.J.
76:03F-057
Blad, B.L.
76:020-007
76:078-013
Blair, J.W.
76:02G-043
Blake, T.R.
76:02F-Q21
Blanchar, R.W.
76:02J-009
Bledsoe, B.E.
76:02G-104
Boaz, M.
Bowman, B.T.
76:026-051
Bowmer, K.H.
76:05B-006
Boyce, J,S.
76:026-023
76:05B-003
Brady, U.E. Jr.
' 76:03F-050
Bras, R.L.
76:028-001
76:028-003
76:028-004
76:028-005
Brehm, R.D.
76:026-115
Bresler, E.
76:02G-127
Buresh, R.J.
76:02K-003
Burgdorf, 0.
76:03F-038
Burnett, E.
76:056-018
76:056-007
Burt, C.M.
76:03F-103
Burt, O.R.
76:06A-006
Busch, J.R.
76:04A-011
Butcher, W.R.
76.-04B-010
Caassen, N.
76:07B-020
76:078-030
253
-------
Cabrera, G.
76:02F-014
76:056-025
Campbell, H.F.
76:05G-012
Campbell, K.L.
76:02E-014
Chaudhry, F.
76:
Chen, K-L.
76:
76:
Chen, L.H.
76:
H.
03F-137
03F-133
07B-025
06B-003
Corey, R.B.
76:02G-111
Couvillon, J.L.
76:03F-129
Crawford, N.H.
76:05B-050
76:05B-052
Campbell, M.D.
76:03F-139
Campbell, R.B.
76:03F-026
Carey, D.I.
76:06C-002
Carlile, B.L.
76:056-021
Carlson, R.E.
76:07B-019
Carlton, A.B.
76:03F-005
Caro, J.H.
76:05B-048
Caro, M.
76:021-010
Carter, D.L.
76:05G-002
Carter, G.E.
76:03F-086
Carter, J.N.
76:03F-083
Cassel, O.K.
76:03F-084
Cerda, A.
76:021-010
Chaiwanakupt, P.
76:05B-045
Chan, Y.K.
76:02J-012
76:046-008
Chang, S.
76:02F-017
Chapman, J.A.
76:050-005
Chapra, S.C.
76:02H-001
Chauhan, H.S.
76:02F-029
Chesness, J.
76:
76:
Chhun, V.H.
76:
Chichester,
76:
Chien, S.H.
76:
Chiu, S.Y.
76;
Chu, S.T.
76
L.
03F-050
03F-129
04A-001
F.W.
05B-019
02G-109
056-051
02G-076
Cull, C.
76:05A-01<1
Chung, K.H.
76: 21-001
Clemetz, D.M.
76:02K-009
Cluff, C.B.
76:036-001
76:03C-012
Colbeck, S.C.
76:02C-001
Coleman, G.
76:020-012
Collins, M.A.
76:02F-009
Colombera, P.M.
76:02G-026
Committee on Oper-
ation and mainten-
ance of irrigation
and drainage sys-
tems of the irri-
gation and drainage
division
76:04A-013
Cooley, J.
76:056-017
Corey, F.C.
76:04A-012
Culler, R.C.
76:020-006
Cunningham, B.A.
76:021-001
Curtain, D.
76:02G-105
Daigger, L.A.
76:03F-088
Dalai, R.C.
76:026-058
Dandy, G.C.
76:05B-028
Dangler, E.W.
76:02G-014
76:02J-001
Daniel, J.F.
76:020-009
Dappo, F.
Das, G.
76:07C-004
76:02F-029
Daud, A.R.
76:03C-015
Davenport, D.C.
76:03B-003
76:038-004
Davidson, J.M.
76:026-024
Davis, D.
76:06A-005
Davis, R.J.
76:028-008
Davis, S.
76:05B-054
Day, R.H.
76:05G-005
Day, T.J.
76:05B-030
254
-------
.Deboer, D.W.
76-04A-002
DeCoursey, D.G.
76:020-012
Dedrick, A.R.
76:03F-131
76:04A-014
Deibert, E.J.
76:020-023
Delleur, J.W.
76:02A-006
Delmas, R.E.
76:03F-096
Delucia, R.J.
76:058-028
Demichele, D.W.
76:05G-006
Dendy, P.E.
76:02J-010
Denmead, O.T.
76:021-007
76:03F-068
Devitt, D.
76:02G-043
DeWalle, D.R.
76:05B-022
76:050-002
Dibb, D.W.
76:03F-082
Dickey, G.L.
76:03F-045
Diestel, H.
76:030-013
Dillow, D.W.
76:058-004
Diskin, M.H.
76:04A-006
76:088-008
Dixon, J.B.
76.-03F-031
Dixon, R.M.
76:02G-034
Doering, E.J.
76:050-003
Donigian, A.S. Jr.
76:058-050
76:058-052
Doran, J.W.
76:02G-068
Doty, C.W.
76:03F-026
Dougherty, J.V.
76:058-040
Douglas, L.A.
76:058-013
Drexler, J.S.
76:03F-087
Dryden, J.R.
76:03F-050
Duckstein, L.
76:02J-008
76:06A-007
76:088-003
Dudley, N.J.
76:06A-006
Duffy, P.O.
76:02E-001
76:058-021
Duich, J.M.
76:030-001
76:03F-053
Duke, H.R.
76:02F-002
76:020-037
Dunigan, E.P.
76:058-001
Dusek, D.A.
76:03F-079
Dyck, F.B.
76:03F-044
Dylla, A.S.
76:03F-048
76:03F-130
76:04A-007
Ebeling, L.L.
76:03F-102
Eccles, L.A.
76:050-014
Edwards, A.P.
76:058-003
Edwards, J.H.
76:021-008
76:03F-023
Ehlers, W.
76:02G-030
Ehlig, C.
76:02F-022
Ehlig, C.F.
76:03F-011
El-Bagoury, I.H.
76:03C-010
El-Demerdash, M.A.
76:03C-010
Eller, R.M.
76:02E-010
Elliott, W.P-
76:02B-002
Ellis, R., Jr.
76:020-027
Elrick, D.E.
76:020-001
76:020-032
E-Rais, M.
76:030-004
El-Swaify, S.A.
76:020-005
76:020-014
76:020-059
76:02J-001
76:030-015
El-Wahidi, A.
76:030-004
Emison, G.A.
76:06A-011
Enfield, C.G.
76.-02G-104
Engler, R.M.
76:02G-021
Englestad, O.P.
76:021-004
Engman, E.T.
76:02G-013
Erickson, E.
76:07B-005
Erie, L.J.
76:03F-131
76:04A-014
Escarzaga, R.
76:02G-064
Evans, D.D.'
76:020-050
Evans, J.K.
76:03F-105
255
-------
Evans, R.G.
76:05G-027
Exner, M.E.
76:05A-004
Fageria, N.K.
76:03F-046
Fangemeier, D.D.
76:03F-110
76:03F-123
76:08B-006
Fanning, D.S.
76:078-001
Fausey, N.R.
76:02G-115
Feldman, M.
76:048-010
Fenn, L.B.
76:020-064
76:020-065
Fernandez, F.G.
76:021-010
Finck, A.
76:030-007
Fink, D.H.
76:040-001
Fitzsimmons, D.W.
76.-04A-008
Flaherty, D.
76:03F-117
Flemal, R.C.
76:05A-002
Flug, M.
76:05G-018
Fluhler, H.
76:02G-052
76-.05A-008
Fogel, M.M.
76:02J-008
Fontenot, W.J.
76:03F-067
Foster, B.B.
76:05B-034
Foster, J.M.
76:02G-048
Francois, L.E.
76:03F-091
Frankenstein, R.L.
76:03F-106
Frere, M.H.
76:05B-048
Fribourg/ H.A.
76:03F-069
Fried, M.
76:02K-021
76-.05B-007
Friedman, I.
76:02E-004
Friedman, Y.
76:03F-019
Fritton, D.D.
76:050-002
Frobel, R.K.
76:03B-001
Fryberger, J.S.
76.-05B-036
Fuchs, M.
76:03F-066
Fults, 0.
76:04A-004
Gallaher, R.N.
76:078-002
Gambell, E.L.
76:06E-001
Gambolati, G.
76:02F-012
Garcia-Maiagayma, J.
76:02K-010
Gardner, B.R.
76:03F-027
Garg, S.K.
76:02F-021
Gascho, G.J.
76:03F-008
76:03F-009
Gavande, S.A.
76:030-012
Gear, R.D.
76:03F-139
Fox, R.L.
76:02K-008
76:03F-056
Gee, G.W.
Gelhar, L.W.
76:058-058
Geohring, L.
76:03F-142
Gerard, C.J.
76:056-006
Gerards, J.
76:03F-109
Ghildyal, B.P.
76:02G-119
Ghiorse, W.C.
76.-02G-020
Ghonsikar, C.P-
76:02K-007
Gibbs, A.E.
76:040-006
Gilbert, R.G.
76:05A-003
Gill, A.C.
76:02J-002
Gill, J.H.
76:056-010
Gillman, R.W.
76:026-083
Glover, R.E.
76:048-002
Goell, A.
76-.03C-004
Goertzen, J.O.
76:03F-047
Goldhamer, D.A.
76:02K-021
Goodling, J.S.
76:020-003
Gormly, J.R.
76:05A-004
Gottfried, G.J.
76:04C-001
Gough, L.P.
76:05B-008
Goyette, E.A.
76:058-009
76:058-011
Graf, W.H.
76:04A-001
76:02G-004
256
-------
Gray
76:06D-001
Gray, W.G.
76:02F-009
76:056-026
Green, R.E.
76:02G-024
Griffith, D.R.
76:Q3F-111
Grigal, D.F.
76:076-012
Groenevelt, H.
76:02G-001
Groenevelt, P.H.
76:02G-032
Guenzi, W.D.
76.-02G-022
76:02G-053
Guillen, M.G.
76:021-010
Guitjens, J.C.
76:058-049
Gum, R.L.
76:06A-008
Gumbs, F.A.
76-.02G-038
Guntermann, K.L.
76:04A-005
Gupta, S.K.
76:02F-006
76:07C-002
Gupta, U.C.
76:03F-015
Gupta, V.
76:02G-010
76:02G-070
76.-02G-088
Gustafson, C.D.
76:03F-136
Haan, C.T.
76:02A-003
76:028-007
76:02J-013
76:06C-002
Hachum, A.Y.
76:02E-012
76:03F-100
Hagan, R.M.
76:038-003
76:038-004
76:030018
Haghiri, F.
76:02G-062
Haise, H.R.
76:03F-078
Haith, D.A.
76:058-040
Halepaska, J.C.
76:02F-022
Halevy, J.
76:03F-042
Hall, A.E.
76.-03E-075
76:07B-014
Hall, B.J.
76:03F-114
Hallberg, R.O.
76:05F-001
Hallsworth, E.G.
76:02G-058
Halvorson, A.D.
76:02G-009
76:07B-003
Hammond, H.
76:058-012
Handv, R.L.
76:02F-030
Hanks, R.J.
76:058-059
76:078-011
Hanna, A.8.
76:03C-011
Hansen, D.C.
76:03E-001
Hanson, C.L.
76:020-004
Hanson, R.L.
76:020-006
Hardan, A.
76:030019
Hardcastle, J.H.
76:05G-019
Hardt, W.F.
76:05G-014
Harlin, C.C.
76:02G-104
Harris, C.R.
76:02G-0'51
Barter, R.D.
7.6.-05B-034
Hassett, J.J.
76:02G-060
Hatfield, J.L.
76:07B-019
Hauser, E.W.
76:02E-002
Hauser, V.L.
76:078-024
Heady, E.G.
76:03F-060
76:06A-007
76:068-002
Heath, R.C.
76:048-011
Hedges, A.M.
76:05B-009
76:05B-011
Heermann, D.F.
76:020-083
76:03F-078
76:060-002
Hefner, J.J.
76:030-017
Heilman, J.L.
76:020-008
Heinemann, H.G.
76:040-004
76:058-002
Helm, D.C.
76:02F-004
76:02F-015
Helweg, O.J.
76:02E-015
76:05G-022
Hendershott, C.H.
76:03F-129
Henderson, G.S.
76:02K-012
Henderson, J.M.
76:03F-038
Henninger, D.L.
76:02G-013
Henninger, N.M.
76:02G-044
257
-------
Henry, J.E.
76:03F-007
Hergert, G.W.
76-.03F-081
Hermann, D.F.
76:03F-039
Hermsmeier, L.F.
76:02F-031
Herrmann, R.
76:04B-009
Humpherys, S.
76:03F-128
Hundal, S.S.
76:020-081
Hunt, C.M.
76:021-009
Hunter, R.B.
76:021-006
Huntington, G.L.
76:02J-005
Johnston, R.S.
76:07B-016
Jones, J.E.
76:02D-006
Jones, J.P-
76:02K-013
Jones, W.E.
76:078-010
Jordan, W.R.
76:03F-055
Hewes, B.J.
76:03F-045
Husenberg, I.
76:07B-030
Jurado Prieto, J.M.
76:05G-025
Hexem, R.W.
76:03F-060
Hicks, D.R.
76:03F-089
Hiler, E.A.
76:026-116
76:02J-016
Hill, W.C.
76:080-001
Hillel, D.
76:020-025
Hills, R.G.
76:05B-030
Hippel, K.W.
76:06A-001
Hipp, B.W.
76:030-016
76:050-006
Hoffman, G.J.
76:030-002
76:030-008
76:03F-075
76:073-014
Holzchuh, J.C., III
76:070-001
Rons, P.M.
76:03F-031
Hornberger, G.M.
"76:02E-010
Howell, T.A.
76.-02G-116
76:03F-135
Hughes, T.D.
76:03F-085
Hull, R.J.
76:021-005
Idoso, S.B.
76:020-005
76:020-039
76:02G-040
Jackson, D.R.
76:020-103
Jackson, E.B.
76:03F-027
Jackson, R.D.
76:020-005
76:020-039
76:02G-040
Jackson, T.L.
76:03F-086
Jacoby, 0.0., Jr.
76:06F-001
Jadav, K.L.
76:03F-072
James, L.G.
76:02G-029
Jarman, 0.D.
76:050-004
Jensen, M.E.
76:03F-083
76:03F-140
76:03F-141
Jettmar, R.U.
76:02E-005
Johnson, A.H.
76:05B-009
76:05B-011
Johnson, C.B.
76:03F-101
Johnston, P.R.
76:02A-005
Jurinak, J.J.
76:05B-059
Jury, W.A.
76:020-007
76:020-008
76:03F-070
76:05A-008
Kaddah, M.T.
76:020-118
76:030-001
76:D5B-016
Kanemasu, E.T.
76:020-002
76:020-008
Kannenberg, L.W.
76:021-006
Kanwar, R.S.
76:02F-029
Kao, T.Y.
Kar, S.
76:02J-013
76:02G-119
Karmeli, D.
76:03F-108
76:03F-132
Keeney, D.R.
76:03F-065
76:050-001
Keisling, T.C.
76:03F-087
Keller, J.
76:03F-103
76:07B-011
76:088-007
Kelly, M.G.
76:02E-010
Kelly, W.E.
76:058-041
258
-------
Kemeny, L.G.
76:03A-001
Kent, D.C.
76:02F-028
Keramidas, V.Z.
76:078-001
Keys, J.W., III
76:05A-009
Khan, M.Y.
76:02F-030
Khasawneh, F.E.
76:021-004
Khepar, S. D.
76:02F-029
Khera, K.L.
76:03F-002
76:03F-041
Khera, R.
76:03F-041
Kiraball, B.S.
76:020-039
76:02G-040
Kimball, D.B.
76-.06A-008
Kimble, J.M.
76:02K-005
76:02K-006
King, T.G.
76:02G-028
Kinnell, P.I.A.
76:02J-004
Kirkham, D.
76:02F-030
76:020-069
Kissel, D.E.
76:026-065
76:056-004
76:05B-018
76:056-007
Kizer, M.A.
76:03F-133
Klein, J.M.
76:056-014
Klingaman, E.D.
76:07B-006
Klute, A.
76:026-083
Koelliker, J.K.
76:03F-063
Koeppe, D.E.
76:02G-060
Kohl, D.H.
76:02G-109
Kohl, R.A.
76:03F-025
Koivo, A.J.
76:05B-029
Kolar, J.J.
76:03F-025
Koli, S.E.
76;03F-058
Kroeker, E.J.
76:056-004
Krueger, C.R.
76:03F-093
Kruse, E.G.
76:026-037
76:088-001
Kuh, H-C.
76:02J-016
Kunkle, G.R.
76:05A-007
Kurtz, L.T.
76:07B-007
Laag, A.E.
76:058-054
Labadie, J.W.
76:02E-015
76:056-022
76:060-002
LaFleur, K.S.
76:058-017
Lai, S.H,
76:07B-005
Lambert, J.R.
76:02G-028
Lane, M.N.
76:03F-029
Lane, W.L.
76:040-006
Langford, K.J.
76:040-003
Langin, E.J.
76:05B-010
Larson, C.L.
76:02G-029
76:02J-017
Larson, D.L.
76:03F-123
Larson, T.E.
76:086-003
Lauenroth, W.K.
76:020-010
Lavno, B.A.
76:05A-006
Lee, K.C.
76:021-001
Lee, M.T.
76:04A-005
Lee, Y.S.
76:021-002
Leggett, J.E.
76:026-086
76:026-117
76:03F-080
LeMert, R.D.
76.-03F-011
Lennox, W.C.
76:058-023
Lessman, G.M.
76:03F-069
Letey, J.
76:026-043
76:026-054
Lettenmaier, D.P.
76:05A-005
Lewis, R.B.
76:07B-024
Lewis, R.J.
76:058-020
Li, R.
76:026-121
Liang, 6.H.
76:021-001
Liegel, E.A.
76:03F-090
Lienesch, W.C.
76:06A-011
Linden, D.R.
76:026-034
259
-------
Linderman, C.L.
76:03F-037
Lindstrom, F.T.
76:058-023
Littlechild, S.C.
76:03F-029
Liu, P.L.-F.
76:02G-098
Lombard, P. B.
76:03F-034
McGurk, F.F.
76:08G-003
McHenry, J.R.
76:02J-002
Mcllhenny, R.C.
76:02G-061
McKean, J.R.
76:060-001
McKenzie, E., Jr.
76:07B-007
Mannering, J.V.
76:03F-101
Manning, D.M.
76:03F-069
Mansell, R.S.
76:02G-091
76:053-012
Marino, M.A.
76:02F-014
76:02G-055
76:056-025
Lomen, D.0.
76:02G-113
76:03F-010
Lonczak, J.
76:070-002
Long, L.L.
76:02E-003
Low, P.F.
76:026-006
Ludwick, A.E.
76:058-010
Lund, L.J.
76:02G-043
76:02G-057
Lyles, L.
76:04A-009
Lytle, R.W., Jr.
76:021-005
McBean, E.A.
76:06A-004
McBride, M.B.
76:02G-112
McCabe, W.J.
76:02D-003
McCandless, D.E., Jr.
76:08E-002
McClurkin, D.C.
76:02E-001
McCown, R.L.
76:02G-096
McElroy, A.D.
76:058-051
McGinness, S.L.
76:04D-003
McGuire, J.A.
76:078-027
McLaren, A.D.
76:026-066
76:058-046
76:058-053
McLaughlin, N.8.
76:03F-044
McLean, E.O.
76:02G-107
McLin, S.G.
76:058-058
McNamara, J.R.
76:05G-008
McNeal, B.L.
76:05G-021
McWhorter, D.B.
76:02F-002
76:02G-082
Maas, E.V.
76:030-008
MacCarthy.- P.
76:02K~Q15
MacDonald, H.C.
76:02F-003
MacLeod, J.A.
76:03F-015
Maddock, T., III
76:048-005
Mahannah, C.N.
76:058-049
Main, R.B.
76:040-006
Malzer, G.L.
76:03F-014
Mann, K.F., Jr.
76:02K-020
Mark, H.B., Jr.
76:02K-015
Marsily, G.D.
76:02E-003
Martin, J.P.
76:026-054
Martin, P.E.
76:03B-003
76:038-004
Martinell, R.
76:05F-001
Massoud, F.I.
76:07B-029
Massoumi, A.M.
76:070-003
Matic, M.
76:026-124
Matocha, J.E.
76:03F-006
76:03F-031
Matsui, E.
76:02E-004
Mawdsley, J.A.
76:020-013
Mayaki, W.C.
76:03F-097
76:03F-098
Mayberry, K.S.
76:03F-092
Mejia, J.M.
76:02A-004
Melamed, J.D.
76:058-059
Mercado, A.
76:058-032
Mickelson, R.H.
76:03F-078
260
-------
Mielke, L.N.
76:03F-037
Miera, F.R., Jr.
76:05B-015
Millar, B.D.
76:021-007
76:03F-068
Miller, D.E.
76:03F-071
Miller, J.B.
76:05A-003
Miller, J.E.
76:02G-060
Miller, R.H.
76:02K-007
Miller, R.J.
76:03F-005
76:05B-005
Miller, W.L.
76:05G-010
Miller, W.W.
76:05B-049
Mitchell, J.K.
76:05G-019
Miyamoto, S.
76:05G-001
Moraghan, J.T.
76:03K-003
Morel-Seytoux, H.J.
76:02G-123
Moreshet, S.
76:03F-066
Morey, D.
76:03F-118
Morrill, L.G.
76:03F-058
Morrissey, M.W.
76:070-002
Mosher, P.N.
76:02G-023
Mualem, Y.
76:02G-090
76:02G-097
Mubarak, A.
76:026-033
Muhamud, Z.
76:06A-010
Muir, J.
76:02G-023
76:05B-003
Naney, J.W.
76:02F-028
Narasimhan, T.N.
76:02F-013
Nash, P.A.
76:02G-057
76:07B-015
Navrot, J.
76:03F-061
76:03F-062
Nebgen, J.W.
76:05B-051
Neher, R.E.
76:05B-015
Nelson, D.W.
76:076-006
Nelson, L.R.
76:05F-057
Neuman, S.P.
76:02E-003
76:02G-089
Neumann, C.A.
76:06B-005
New, L.L.
Munn, D.A.
76:02G-107
76:03F-043
76:03F-079
Moberg, E.L.
76:030-001
Munn, J.R., Jr.
76:02J-005
Newman, R.C.
76:02K-014
Mohammed, R.A.
76:03F-110
Moldenhauer, W.C.
76:02J-003
Molz, F.J.
76:02G-091
76:02G-114
Mondart, C.L., Jr.
76:058-001
Moody, W. T.
76:046-002
Moore, J.
76:030-017
Moore, J.L.
76:06A-003
Moore, R.A.
76:03F-093
Moore, S.F.
76:05B-028
Munns, D.N.
76:02K-004
76:02K-008
Murtha, G.G.
76:02G-096
Musick, J.T.
76:03F-043
76:03F-079
Musy, A.
76:088-003
Myers, R.G.
76:05D-005
Nahlawi, N.
76:030-012
Nakayma, F.S.
76:02G-039
76:02G-040
Nanagara, T.
76:02G-086
76:02G-117
Newton, D.W.
76:02G-027
Nicholas, E.G.
76:040-005
Nickell, C.D.
76:03F-097
Nicol, K.J.
76:06A-007
Nielson, D.R.
76:02G-080
76:02G-084
Nienkerk, M.M.
76:05A-002
Nobeli, 0.
76:058-055
Nofziger, D.L.
76:02G-108
Noggle, J.C.
76:021-009
261
-------
Nudds, D.
76:060003
Nuttall, W.F.
76:03F-076
Nyhan, J.W.
76:058-015
O'Connor, D.J.
76:076-022
O'Connor, G.A.
76:05A-014
76:05B-014
Office of Water
Research and Tech-
nology
76:05B-035
O'Loughlin, E.M.
76:05B-006
Olson, R.A.
76:02G-033
76:056-003
Olson, T.C.
76:02J-003
O'Neill, K.
76:02F-008
Onstad, C.A.
76:02J-014
Oron, G.
76:03F-108
Osborn, J.
76:02G-054
Oschwald, W.R.
76:02J-015
Oster, J.D.
76:03F-047
76:05A-012
Page, A.L.
76:02K-010
Pal, U.K.
76:03F-074
Papanicolaou, E.P.
76:058-055
Parchomchuk, P.
76:088-004
Parker, J.H.
76:03F-116
Parker, J.J.
76:03F-004
Parlange, J.-Y.
76:02G-036
76:02G-067
76:02G-071
76:02G-094
76:02G-095
76:02G-106
Parra, M.A.
76:03C-005
Pasricha, N.S.
76:02K-018
Patrick, W.H., Jr.
76:02G-021
76:02G-045
76:02G-046
76:026-056
76:02G-061
76:03F-067
76:03F-077
76:078-004
Patton, P.C.
76:02E-007
Paulsen, G.M.
76:02G-027
76:021-001
Pearson, F.J., Jr.
76:02F-024
Pennell, A.8.
76:02J-017
Pepper, I.L.
76:02K-007
Petersen, G.W.
76:02G-013
Peterson, C.M.
76:02G-111
Peterson, H.B.
76:03C-006
Peterson, L.A.
76:02K-014
Peterson, R.H.
76:03F-089
Petrosian, G.P.
76:03C-014
Pettyjohn, W.A.
76:058-039
Pfannkuch, H.0.
76:05A-006
Phelan, R.A.
76:058-001
Phene, C.J.
76:03F-033
76:03F-095
Philip, J.R.
76:02G-026
Phillips, G.
76:058-029
Phillips, R.E.
76:02G-002
76:02G-056
76:02G-086
76:02G-117
76:03F-080
Pickens, J.F.
76:056-024
Piest, R.F.
76:040-004
Pilgrim, D.H.
76:02A-005
Pinder, G.F.
76:058-026
Pisano, M.A.
76:05G-015
76:056-016
Plamenac, N.
76:026-124
Polasek, R.B.
76:058-043
Ponnamperuma, F.N.
76-.02K-018
Posin, Y.
76:078-030
Poulovassilis, A.
76:026-102
Powell, N.L.
76:026-069
Powers, W.L.
76:020-002
Prasad, M.
76:02K-016
76:03F-032
76:03F-064
Prather, R.J.
76:026-012
Pratt, P.P.
76:026-057
76:058-053
76:056-054
76:078-015
262
-------
Prihar, S.S.
76:03F-002
76:03F-041
Printy, w.L.
76:03F-072
Pruitt, W.O.
76:03C-018
Quirk, J.P.
76:02G-110
Quisenberry, V.L.
76:020-002
Raats, P.A.C.
76:02G-012
76:02G-019
76:02G-128
Ragade, R.K.
76:06A-001
Raguse, C.A.
76:03F-096
Rahman, A.
76:026-005
Rajan, S.S.S.
76:02K-002
Ramadurgaiah, D.
76:02F-033
Ramsey, M.K.
76:086-006
Randall, G.W.
76:02G-111
Rao, M.J.
76:03F-094
Rasmussen, L.A.
76:02A-001
76:02A-002
Rasmussen, V.P.
76:078-011
Rasnake, M.
76:02G-031
Rauschkolb, R.S.
76:03F-005
Rausser, G.C.
76:06A-002
Raveh, J.
76:02G-047
Ravelo, C.
76:02G-116
Reddell, D.L.
76:02J-016
76:02J-122
76:03F-102
76:06A-009
76:078-023
Reddy, A.S.
76:02G-017
Reddy, K.R.
76:02G-045
76:02G-046
76:02G-056
76:03F-077
76:078-004
Reginato, F.S.
76:02G-039
76:02G-040
Reginato, R.J.
76:02D-005
Reisosky, D.C.
76:020-001
76:03F-026
Reklig, D.M.
76:Q6A^006
Rektorik, R,J.
76:04A-009
76:05G-009
Remson, I.
76:043-001
Reule, C.A.
76:078-003
Reuss, J.O.
76:03F-081
76:058-010
Rhoades, E.D.
76:03F-040
Rhoades, J.D.
76:02G-009
76:02G-012
76:026-015
76:03C-001
76:05A-010
76:05A-012
76:058-016
Rhoads, F.M.
76:058-012
Rible, J.M.
76:026-057
Rice, R.C.
76:02F-019
Rich, L.R.
76:04C-001
Richards, G.E.
76:03F-113
Richardson, C.W.
76:03F-040
76:058-018
76:056-007
Richey, C.B.
76:03F-111
Riego, D.C.
76:02J-009
Risseeuw, J.
76:056-025
Ritchie, E.A.
76:05G-013
Ritchie, J.C.
76:02J-002
Ritchie, J.T.
76:02D-001
76:03F-036
76:03F-040
Rivera, R.A.
76:03F-045
Roa, P.S.C.
76:026-024
Robbins, J.L.
76:02K-009
Roberson, J.A.
76:04A-003
Roberts, E.B.
76:03A-004
Robertson, W.K.
76:058-045
Robinson, F.E.
76:03C-009
76:03F-092
76:03F-134
Rochester, E.W.
76:07B-027
Rodarte, L.
76:02F-007
Rodriguez-Iturbe, I.
76:028-001
76:028-003
76:028-004
76:028-005
263
-------
Roefs, T.G.
76:06A-008
Rogers, R.D.
76.-02G-042
Rolston, D.E.
76:026-055
76:02K-021
76:03F-005
Romero, G.C.
76:030-005
Rosenberg, N.J.
76:020-007
76:07B-013
76:078-021
Ross, J.D.
76:07B-024
Ross, R.
76:03F-127
Rouse, W.R.
76:02D-011
Rousselle, J.
76:02A-004
Ruff, J.P.
76:080-001
Runnells, D.D.
76:05B-038
Rushton, K.R.
76:04B-007
76:04B-008
Ryan, J.
76:05G-001
Ryden, J.C.
76:02K-001
Rykbost, K.A.
76:050-004
Safaya, N.M.
76:03F-013
Saffigna, P.G.
76:03F-065
Saini, G.R.
76:03F-054
Sainty, G.R.
76:05B-006
Salati, F.
76:02E-004
Sammis, T.W.
76:02G-050
Sander, D.H.
76:03F-088
Sanders, D.C.
76:03F-095
Sandhu, B.S.
76:03F-002
76:03F-041
Sandhu, K.S.
76:03F-002
76:03F-041
Sandoval, P.M.
76:05G-003
Sands, C.D.
76:03F-123
Saurez, D.L.
76:05A-010
Sawhney, B.L.
76:02G-036
76:02G-067
Saxena, M.C.
76:03F-074
Sayre, W.W.
76: 08B-005
Schaake, J. C., Jr.
76:06A-004
Schiele, L.H.
76:02G-Q75
Schleicher, J.
76:03F-107
Schlute, D.D.
76:02G-111
Schmisseur, W.E.
76:060-001
Schmedl, D.
76:03F-115
Schneider, A.D.
76:03F-043
76:03F-138
Schneider, R.R.
76:05G-005
Scholl, D.G.
76:026-041
Schreiber, J.D.
76:02E-001
76:05B-021
Schull, H.H.
76:04A-007
Schulte, D.D.
76:056-004
Schultz, R.K.
76:058-046
Schuman, G.E.
76:03F-037
Schwab, G.O.
76:026-081
Seely, E.H.
76:02F-028
Seim, E.G.
76:026-023
76:056-003
Selim, H.M.
76:026-091
Selim, M.
76:05B-012
Sentis, I.P.
76:070-004
Sepaskhah, A.R.
76:03F-051
Severson, R.C.
76:058-008
76:078-012
Shade, J.W.
76:05A-007
Shaffer, M.J.
76:058-056
Sharma, M.L.
76:021-003
Sharpe, P.J.H.
76:056-006
Sharpless, R.G.
76:03F-072
Shaw, K.
76:05B-006
Shearer, G.
76:02G-109
Sheikholslami, M.R.
76:03F-001
Shelton, C.H.
76:02E-011
Shelton, J.E.
76:03F-035
Sheridan, J.M.
76:058-047
264
-------
Sherman, B.
76:02A-008
76:02E-009
Shull, H.
76:03F-039
76:03F-048
76:03F-130
Shuman, L. M.
76:02K-019
Shupe, J.L.
76:030-006
Sichani, S.A.
76:03F-051
Siefert, W.
76:03F-119
Siemens, J.C.
76:02J-015
Sigvaidason, O.T.
76:048-003
Sikora, L.J.
76:050-001
Sill, B.L.
76:020-003
Simons, D.B.
76:02G-121
Sims, P.L.
76:020-010
Sinanuwong, S.
76:030-015
Sinha, B.K.
76:053-044
Skaggs, R.w.
76:02F-005
76:020-120
76:03F~018
76:07B-003
Skogerboe, G.V.
76:050-018
76:05G-026
76:050-027
Sloneker, L.L.
76:02J-003
Smajstria, A.
76:02G-122
76:07B-023
Smiles, D.E.
76:02G-001
Smillie, G.W.
76.-02G-105
Smith, E.M.
76:03F-105
Smith, G.D.
76:02G-096
Smith, O.L.
76:03F-012
Smith, R.B.
76:058-005
Smith, R.E.
76:020-072
Sonu, J.
76:020-123
Sowell, R.S.
76.-06B--003
76:06B-004
Spalding, R.F.
76:05A-004
Sparks, D.
76:04A-004
Spomer.- R.G.
76:040-004
Sposito, 0.
76:02G-010
76:020-070
76:020-088
Sposito, V.A.
76:03F-060
Stallings, J.L.
76:078-027
Stanhill, 0.
76:03F-060
Stanley, C.D.
76:07B-019
Staple, W.J.
76:02G-016
Starr, J.L.
76:020-106
Steele, K.F.
76:02F-003
Singh, B.B.
76:02K-013
Singh, B.P.
76:03F-052
Singh, G.
76:03F-049
Singh, M.
76:058-042
Singh, N.T.
76:058-044
Singh, R.
76.-02F-020
Singh, V.P.
76:02A-008
76:02E-006
76:02E-009
Smith, S.J.
76:05B-004
Smith, S.W.
76:03F-104
76:03F-142
76:050-018
76:050-027
Sneed, R.E.
76:068-003
76:06B-004
Snyder, G.H.
76:03F-008
76:03F-009
So, H.B.
76:020-110
Sollo, F.W.
76:080-003
Sommerfeldt, T.G.
76:03F-044
Sterling, J.D.E.
76:03F-015
Stevens, M.A.
76:020-121
Stewart, B.A.
76:058-048
Stewart, J.I.
76:030-018
Stewart, R.B.
76:020-011
Stiver, J.F.
76:02G-004
Stolzy, L.H.
76-.02G-052
76:05A-008
76:058-046
265
-------
Stone, L.R.
76:020-002
, „ , , 76:03F-097
' "u 76:03F-098
Strack, O.D.L.
76:02F-023
Street, J.O.
76:02B-007
Streltsova, T.D.
76:02F-016
76:02F-018
Struchtemeyer, R.A.
76:03F-049
Subramanyam, T.K.
76:02G-119
Sullivan, D.M.
76:021-005
Sussman, M.W.
76:03F-045
Swank, W.T.
76:02K-012
Swartzendruber, D.
76:026-108
Sweeten, J.M.
76:06A-009
Swift, L.W., Jr.
76:07B-017,
Syers, J.K.
76:02K-001
Szidarovszky, F.
76:06A-005
Tabor, M.
76:03F-034
Taggard, K.L.
76:03F-096
Tang, Y.
76:02G-120
Tangborn, W.V.
76:02A-001
76:02A-002
Tanji, K.K.
76:02F-006
76:05B-007
76:05B-057
76:070-002
Tanner, C.B.
76:03F-065
76:03F-070
Tao, P.C.
76:02A-006
Tarapchak, S.J.
76:02H-001
Taylor, G.S.
76:02G-081
Teare, I.D.
76:03F-097
76:03F-098
Temple, J.E.
76:02E-011
Tengah, A.
76:030-015
Terman, G.L.
76:021-004
76:021-009
Thomas, A.W.
76:02G-018
76:02G-037
Thomas, G.W.
76:026-031
Thomas, J.C.
76:03F-055
Thompson, E.S.
76:02B-006
Thompson, 6,T,
76:04A-OQ3
Tideje, J.M.
76:07B-005
Tock, D.G.
76:OSG-011
Tollner, E.W.
76:02J-013
Tompkins, F.D.
76:02E-011
Towle, C., Jr.
76:03F-123
Towner, 6.D.
76:026-093
Trava, J.
76:060-002
Treitz, W.
76:030-013
Trelease, F.J., III
76:06E-002
Triplett, G.B., Jr.
76:03F-007
Trump.;, C.L.
76:02B-002
Tsai, Y.J.
76:05B-027
76:05B-033
Tsuji, G.Y.
76:02G-049
Turnbull, J.W.
76:02E-002
Turner, N.C.
76:026-036
Unger, P.W.
76:026-078
76:03F-004
Unny, T.E.
76:06A-001
Valantine, V.E.
76:050-001
Valoras, N.
76:026-054
Van Bavel, C.H.M.
76:026-025
Van Cleemput, O.
76:026-061
76:02K-017
Van;Dam, J.C.
76:02L-001
Van Deman, J.M.
76:068-004
VanDemark, S.C.
76:050-002
Van de Pol, R.M.
76:05Br007
Van der Kamp, 6.
76:02F-011
Van der Ploeg, R.R.
76:026-003
Van Doren, D.M., Jr*.
76:03F-007
Van 6enuchten, M. Th.
76:026-035
76:05B-014
van Hoorn, J.Wi.
76:056-025
266
-------
van Schilfgaarde, J.
76:02G-015
76:03F-047
Varade, S.B.
76:020-119
Varlev, I.
76:03F-099
Verma, S.B.
76:020-007
76:07B-021
Vikovik, M.
76:02G-124
Viskanta, R.
76:05B-030
Vithayathil, F.
76:020-109
Vols, M.G.
76:056-046
Waddington, D.V.
76:030-001
76:03F-053
Wade, J.C.
76-.06A-007
Wagner, G.H.
76:02F-003
Walker, M.E.
76:03F-087
Walker, W.R.
76:03F-104
76:03F-108
76:03F-109
76-.03F-132
76:03F-142
76:05G-018
76:05G-024
76:05G-027
Wall, G.J.
76:02J-006
Wallihan, E.F.
76:03F-072
Walsh, L.M..
76:03F-090
Warkentin, B.P.
76:02G-038
Warneke, J.. E.
76:07B-015
Warrick, A.W.
76:02G-OSO
76:02G-113
76:03F-010
Watkinson, J. H.
76:02K-002
Watschke, T.L.
76:030-001
Watson, K.K.
76:02G-011
Weatherford, G.D.
76:06F-001
Weaver, J.B.
76:03F-094
Weber, J.E.
76:02J-008
Wegner, J.W.
76:06F-001
Welch, L.F.
76:03F-082
Weldon, C.O.
76:07B-002
Wells, L.G.
76:Q2G-077
Wenberg, R.D.
76:02F-032
Wensink, R.B.
76:03F-133
76:078-025
Westcot, D.W.
76:05A-013
Westermann, D.T.
76-.03F-083
Westfall, D.G.
76:03F-112
Wheaton, R.Z.
76:03F-101
Wheeler, W.B.
76:058-012
Whisler, F.D.
76:02G-011
76:02G-018
76:02G-074
White, A.W., Jr.
76:02E-002
White, E.M.
76:03F-093
White, I.
76:026-026
Whitlow, P.
76:02G-109
Whitson, E.N.
76:03F-052
Whittlesey, N.K.
76-.04B-010
Wierenga, P.j.
76:02G-035
76:05B-014
Wiggert, D.C.
76-.02F-026
Wilding, L.P.
, 76:02G-107
76-.02J-006
Willardson, L.S.
76:03F-047
76:03F-100
76:058-059
Williams, J.R.
76:02E-013
Willis, C.E.
76:06A-002
Willis, R.
76:050-003
Wilson, C.R.
76:02F-010
Wilson, G.D.
76:078-011
Winogard, I.J.
76:02F-024
Wischmeier, W.H.
76:02J-011
76:058-048
Witherspoon, P.A.
76:02F-010
76:02F-013
Wolfe, J.W.
76:03F-034
76-.03F-133
76:078-025
Wood, E.F.
76:02A-007
Wood, I.R.
76:058-030
Woolhiser, D.A.
76:058-048
Worstell, R.V.
76:03F-003
76:04A-010
267
-------
Worthington, P.F.
76:02F-027
Wright, G.P.
76:05G-011
Wright, J.L.
76:03F-140
76:03F-141
Wylie, E.B.
76:02F-026
Yeh, G.T.
76:05B-033
Yeh, W. W-G.
76:02F-017
76:04A-004
76:058-027
Yotsukura, N.
76:08B-005
Young, D.A.
76:086-001
Young, G.K.
76:02E-005
Young, P-
76:05B-042
Young, R.A.
76:02J-014
Youngs, E.G.
76-.02G-102
Zachraann, D.W.
76:026-037
Zahran, M.A.
76:03C-012
Zajicek, O.T.
76:05B-043
Zamir, S.
76:04A-006
Zartman, R.E.
76:026-086
76:03F-080
Zimdahl, R.L.
76:02G-048
Zivkovik, B.
76:02F-034
Zolezzi, 0.
76:02G-116
268
-------
SECTION XLI
SUBJECT INDEX
Absorption
76:020-001
76-:02G-085
76:020-086
76:02G-101
76:021-004
76:02K-009
76:02K-015
76:03F-012
76:03F-014
76:03F-023
76:03F-082
Acidic Soils
76:03F-006
Adhesion
76:038-001
Administration
76:03F-028
Adsorption
76:02C-001
76:02G-091
76:02G-035
76:02G-054
76:02G-104
76:02K-002
76:02K-005
76:02K-006
76:02K-008
76:02K-019
76:058-014
Advection
76:02C-001
76:020-002
76:020-007
76:078-013
Aeration
76:05F-001
Aerial Photography
76:020-006
76:040-005
Aerobic
76:020-046
Aerobic Conditions
76:02G-056
Aesthetics
76:06A-008
Africa
76:078-028
Agricultural Engineering
76:088-003
Agricultural Runoff
76:05A-001
76:058-001
76:058-035
76:058-040
76:05G-005
76:05G-007
76:06E-001
76:078-006
Agricultural Soils
76:02G-042
Agricultural Watersheds
76:02A-008
76:02E-002
76:02E-006
76:02E-009
76:03F-063
76:04A-005
76:058-002
76:058-019
76:058-040
76:05G-007
Agriculture
76
76;
76:
76;
76;
76;
76;
76;
76;
76:
76;
76;
76;
76;
76;
76
76
76;
76;
76;
76;
02G-002
02G-011
02G-081
03F-019
03F-028
03F-030
03F-112
03F-113
03F-135
05A-003
05A-013
058-011
058-036
058-037
058-040
05G-002
05G-005
05G-010
06A-003
06A-007
06E-001
Agronomy
Air
76:03F-028
76:020-003
76:02G-082
Acrricultural Chemicals
76:058-003
Air Circulation
76:02G-089
76:03F-052
Air Temperature
76:02D-003
76:020-011
76:058-022
76:078-021
Air-Water Interfaces
76:02G-071
76:02G-082
76:058-022
Alabama
Albedo
Alfalfa
Algae
76:020-009
76:078-027
76:020-005
76:020-023
76:02K-013
76:03F-025
76:03F-076
76:03F-093
76:07B-013
76:021-002
Algorithms
76:028-003
76:026-004
76:02F-017
76:04A-004
76:078-017
Alkali
76:02K-018
Alluvial Aquifers
76:048-009
Alternative Costs
76:06C-001
Alternative Planning
76:050-005
76:06A-004
Alternative Water Use
76:06C-001
Altitude
76:02A-001
Aluminum
Ammonia
76:02K-005
76:02K-006
76:020-064
269
-------
Ammonia
(cont.)
76:021-001
76:03F-006
76:03F-032
76:056-001
76:058-013
76:05G-001
76:078-006
Ammonium
76:03F-082
Ammonium Compound
76:02G-056
76:02G-064
Anaerobic
75:02G-046
Anaerobic Conditions
76:02G-044
76:02G-056
Analog Models
76:02F-019
Analysis
76:02F-001
76:02F-020
76:02F-021
76:078-003
Analvtioal
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
Techniques
:02A-004
:02A-007
:02B-001
:02B-006
:02D-006
:02D-012
:02E-003
:02E-005
:02E-008
.-02F-014
:02F-026
:02G-006
.-02G-011
:02G-019
:02G-035
:02G-085
:02G-091
:02G-095
:02G-098
:02J-008
:02J-110
:02J-012
:05A-002
:05A-005
:05B-001
:05B-002
:05B-004
:05B-027
:05B-031
.-05B-033
:05G-007
:07B-003
:07B-006
:07C-001
Anion Adsorption
76~:02K-002
Anion Exchange
76:02K-009
Aquifer Testing
76:02F-011
76:02F-019
76:048-007
76:048-008
Anions
76:02K-002
76:02K-012
Aquifers
Anisotropy
76:02F-005
76:02G-017
Annual
76:02J-010
Antitranspirants
76:036-003
76:03B-004
Appalachian Mountain Region
76:02K-012
Application Methods
76:03B-003
76:038-004
76:03P-001
Approximation Method
76:02G-082
Aquatic Environment
76:02E-010
76:02G-027
Aquatic Population
76:02G-027
Aquatic Weeds
76:058-006
Aqueous Solutions
76.-02G-091
Aquicludes
76:02F-007
Aquifer Characteristics
76:020-009
76:02F-001
76:02F-004
76:02F-011
76:02F-015
76:Q2F-027
76:02F-029
76:04B-006
76:048-007
76:048-008
76:07C-001
Aquifer Systems
76:Q2F-004
76.-02F-006
76:02F-007
76:02F-015
76
76
76:
76;
76:
76;
76:
76:
76:
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
:02F'
:02F-
:02F-
:02F-
:02F-
:02F-
:02F-
;02F-
:02F-
:02F-
:02F-
02F-
02F-
02F-
02F-
02F-
04A-
04B-
04B-
04B-
048-
04B-
05A-
05A-
05A-
05A-
05A-
050-
05G-
05G-
-003
-006
-007
-009
-Oil
-014
•016
-018
•019
•022
•023
•024
•029
•030
033
•102
002
001
•002
009
010
Oil
006
025
032
036
058
003
009
019
Aquitards
Areal
76:02F-004
76:02F-006
76:02F-007
76:02F-015
76:02F-016
76:02F-018
76:02B-003
76:028-004
Arid Climates
76:020-006
Arid Lands
76:02G-007
76:02G-008
76:02G-009
76:02K-020
76:03A-001
76:03F-024
76:040-001
76:05B-038
Arizona
76:020-006
76:02G-050
76:03F-024
76:03F-027
76:04B-006
270
-------
Arizona
(cont.)
76:040-001
76:06A-008
Arkansas
76:02F-003
Arsenic Compounds
76:058-020
Artesian Aquifiers
76:02F-033
Artesian Heads
76:02F-007
76:02F-011
Artesian Wells
75:02F-033
76:048-002
Artificial Recharge
76:02F-025
Barriers
Asphalt
76:038-001
76:03F-044
Assessment
76:048-003
76:06A-003
Atmosphere
76:028-006
76:020-013
76:02K-012
76:03F-030
76:058-022
Atmospheric Physics
76:020-017
Atmospheric Pressure
76:020-082
Australia
76:021-003
76:03A-001
Automation
76:03F-131
76:04A-014
Available Water
76:02G-092
Average
76:028-001
Bacteria
Barley
76:050-001
76:02K-013
76:03F-015
76:03F-076
76:058-046
76:038-001
Base Flow
76:02F-014
76:02F-017
76:02F-026
Baseline Studies
76:058-021
Basins
Beans
76:02A-006
76:028-005
76:03F-131
76:04A-014
76:05G-026
76:02K-013
76:03C-005
76:030-009
76:03F-051
76:03F-061
76:03F-062
76:03F-140
76:05B-010
Behavior
Boundaries (Surfaces)
76:02G-073
76:020-082
76:020-092
76:020-098
76:020-100
76:020-101
76:02J-012
76:03F-018
Boundary Layers
76:020-008
76:020-013
Boundary Processes
76:02F-009
76:020-071
Brackish Water
76:02F-023
Brine Disposal
76:058-036
Brines
76:058-039
76:050-012
76:06A-001
Benefits
76:04A-005
76:04A-006
76:06A-003
76:06A-005
76:06A-006
Bermuda Grass
76:020-031
76:03F-031
Bibliographies
76:058-035
Biochemical Oxygen Demand
76:058-029
76:058-042
76:050-008
Biochemistry
76:058-032
Biological Treatment
76:050-001
Border Irrigation
76:04A-008
Boron
76:02K-014
76:03F-015
76:058-055
Boulder Canyon Project Act
76:06F-001
Bulk Density
76:020-038
76:020-108
76:020-118
76:020-119
Buoyancy
Burning
Cadmium
76:05B-027
76:04C-001
76:020-060
76:02G-062
76:02K-010
Calcareous Soils
76:020-064
76:020-065
76:02K-016
76:03F-006
76:03F-032
Calcium
76:020-062
76:020-126
76:021-001
76:02K-001
76:02K-004
76:03C-007
76:03C-011
76:03F-014
76:03F-046
76:03F-069
76:03F-087
76:056-054
76:078-012
76:07C-004
271
-------
Calcium Carbonate
76:02J-006
76:08G-003
Calibrations
76 :08B-001
76:08G-001
California
76:02F-004
76:02F-006
76.-02P-015
76:02F-031
76:026-118
76:03C-001
76.-03F-045
76:03F-141
76:04A-004
76:056-005
75:058-016
76.-05G-013
76 :05G-014
76:05G-020
76:06A-002
Carbonates
76:058-015
Canada
76:046-003
Canal Seepage
76:04A-010
Canals
Canopy
76:02G-017
76:03F-028
76:04A-010
76:036-003
76:036-004
76:03F-052
76:076-013
Capillary Action
76:02G-019
76:02G-037
76:02G-071
Capillary Conductivity
76:02G-090
76:02G-097
Carbon
76:02J-002
76:050-001
Carbon Dioxide
76:076-005
76:07B-021
Carbonate
76:02F-003
76:05A-002
76:05A-007
76:056-015
Carbonate Rocks
76:02F-024
Carrots
76:03C-009
76:03F-092
Cathodic Protection
76:05G-009
76:05G-013
Cation Adsorption
76:02G-051
76:02G-112
Cation Exchange
76:02G-060
76:02G-065
76:02G-105
76:02K-004
76:03F-006
76:073-008
Cations
76:02E-001
76:02G-051
76:02K-012
76:058-045
76:05G-021
Centrifugal Pumps
76:05G-009
Centrifugation
76:02G-080
Channel Flow
76:04A-003
76:05B-031
76:086-005
Channel Improvement
76:03F-044
Channel Morphology
76:058-030
Channels
76:04A-001
Chemcontrol
76:036-003
Chemical Analysis
76:05A-002
76:05A-003
76:05A-006
76:076-003
Chemical Degradation
76:02G-022
76:05A-007
Chemical Precipitation
76:056-038
Chemical Properties
76:02K-012
Chemical Properties
(cont.)
76:03C-001
76:076-003
Chemical Reactions
76:02K-003
76:02K-005
76:058-038
76:050-001
Chemical Wastes
76:05G-001
Chemicals
76:02K-003
Chemistry of Precipi-
tation
76:056-021
Chiseling
76:03P-026
Chloride
76:021-010
Chlorides
76:02G-002
76:02G-027
76.-02G-043
76:02G-047
76:03F-091
76:058-032
76:056-037
76:058-039
76:058-044
76:05G-003
76:076-015
76:076-030
Chlorine
76:03C-004
Chlorophyll
76:02H-001
Chromium
76:02K-005
76:02K-006
Citrus Fruits
76-.05G-014
Clay Loam
76:02G-002
76:02G-005
76:02G-078
Clay Soils
76.-02G-047
Clays
76:020-001
76:02G-001
76:02G-006
76:02G-027
272
-------
Clays
(cont.)
76:02G-
76:02G-
76:02G-
76:02G-
76:02G-
76:02G-
76:02G-
76:02K-
76:02K-
76:02K-
76:02K-
76.-02K-
76:03F-
76:03F-
76:03F-
76:058-
76:05G-
032
038
059
062
108
112
124
002
010
018
019
020
•001
061
•062
•018
•019
Climate
76:076-027
Climatic Data
76:03F-141
Cloud Cover
76:028-006
Cloud Seeding
76:028-008
Clovers
Coal
76:03F-096
76:05G-018
76:063-002
Coastal Marshes
76-.02G-021
Coastal Plains
76:05G-021
Coasts
76:02F-023
76:03A-001
76:05G-011
Colorado
76:020-010
76-.03F-060
76:03F-078
76:03F-141
76:058-010
76:05G-024
76:05G-027
76:060-001
Colorado River
76:03E-001
76:03F-134
76:040-006
76:05G-021
76:05G-027
76:06F-001
Colorado River Basin
76:040-006
76:05G-027
76:06F-001
Colorado River Compact
76:06F-001
Columbia River
76:068-005
Compaction
76:02F-004
76:02F-015
Comprehensive Planning
76:06A-004
Compressibility
76:02G-082
Compressive Strength
76:02G-081
Computer Models
76:02F-004
76:02F-015
76:02G-008
76:02G-028
76:02G-072
76:02G-073
76:03F-030
76:03F-040
76:03F-108
76:048-007
76:048-008
76:05B-025
76:058-029
76:058-084
76:05G-006
76:06A-004
76:06A-006
76:068-002
76:068-003
76:06B-004
76:078-017
76:078-025
76:07C-002
Computer Programs
76:02F-014
76:02F-028
76:02G-127
76:03F-019
76:03F-124
76:03F-125
76:03F-133
76.-06A-003
76:068-002
76:068-004
76:07B-020
76:07C-001
76:07C-002
Computers
(cont.)
76:02F-013
76:02F-020
76:02G-011
76:02G-029
76:03F-133
76.-04B-007
76:058-023
76:05B-026
76:06A-002
76:078-027
76:07C-002
Conduction
76:02F-013
76:02F-027
Conductivity
76:02G-009
76:02G-080
76:05A-005
76:05B-041
76:07B-002
Confined Water
76:02F-022
Conjunctive Use
76:048-010
Connate Water
76:02F-006
Conservation
76:03C-001
76:03F-030
76:058-002
76:05G-015
Constraints
76:02F-017
76:03F-019
76:03F-029
76:04B-001
76:05G-008
76:05G-010
76:06A-002
Construction
76:03F-003
Construction Cost
76:06A-005
Consumptive Use
76:020-006
76:038-003
76:03F-011
Continuity Equation
76:02F-009
76:02F-021
76:02G-082
Computers
76:028-004
76:02F-005
Control
76:05G-017
273
-------
Control Systems
76:05G-017
Convection
76:02F-008
76:02F-021
76:058-026
Copper
Cores
Corn
76:03F-013
76:03F-061
76:03F-062
76:058-055
76:078-001
76:02F-028
76:03F-018
76:058-003
76:078-004
76:020-
76:02G-
76:026-
76:026-
76:021-
76:021-
76:021-
76:021-
76:02J-
76.-03C-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76.-03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:05B-
76:058-
76:07B-
76:078-
76:078-
001
023
048
117
002
006
008
009
015
018
006
007
013
014
033
041
060
069
078
081
082
089
•090
09S
101
010
044
019
020
024
Corn (Field)
76:02G-086
76:021-004
76:03F-023
76:03F-026
Correlation Analysis
76:02A-004
76:02A-006
76:028-001
76:028-006
76:020-006
76:02E-005
Corrosion
76:05G-009
76:05G-013
76:08G-003
Cost Allocation
76:06A-002
Cost Analysis
76:05G-009
Cost-Benefit Analysis
76:050-003
76:06A-007
Costs
76:028-004
76;03A-001
76.-03F-029
76:04A-005
76:04A-006
76:048-005
76:058-028
76:06A-002
76:08B-003
Cotton
76:02G-114
76:03C-016
76:03F-019
76:03F-042
76:03F-055
76:03F-058
76:03F-094
76:03F-110
76:04A-009
76:05G-007
Cotton Evaporation
76:03F-004
Cottonwoods
76:03B-003
76:038-004
Cracks
76:02F-010
Crop Production
76:02F-031
76:026-016
76:02G-058
76:021-004
76:021-006
76:02J-015
76:03C-005
76:03C-007
76:03C-008
76:03C-009
76:03C-010
76:03C-012
76:03C-013
76:03C-014
76:03C-017
76:03C-018
76:03C-019
76:03F-002
Crop Production
(cont.)
76:03F-008
76:03F-009
76:03F-011
76:03F-012
76:03F-013
76:03F-014
76.-03F-015
76:03F-024
76:03F-026
76:03F-027
76:03F-035
76:03F-036
76:03F-039
76:03F-041
76:03F-043
76:03F-046
76:03F-051
76:03F-052
76:03F-053
76:03F-054
76:03F-055
76:03F-057
76:03F-058
76:03F-060
76.-03F-063
76:03F-066
76.-03F-067
76:03F-070
76:03F-072
76:03F-073
76:03F-078
76:03F-088
76:03F-095
76:03F-099
76:03F-101
76:03F-110
76:03F-112
76:03F-113
76:03F-114
76:03F-119
76:03F-126
76:03F-134
76:03F-135
76:03F-136
76:03F-139
76:03F-140
76:03F-14l
76:03F-143
76:04A-009
76:04A-012
76:05A-013
76:058-006
76:058-007
76:05C-002
76:05G-006
76:056-021
76:06A-007
76:068-003
76:068-004
76:060-002
76:078-010
76:078-011
76:078-024
76:07B-027
76:078-030
76:070-004
274
-------
Crop Response
76:020-007
76:020-008
76:02G-058
76:020-075
76-.02G-081
76:02G-116
76:02G-117
76:02G-118
76:021-002
76:021-004
76:021-006
76:021-009
76.-03C-004
76:030-005
76:030019
76:030-001
76:03P-002
76:03F-007
76:03F-008
76:03F-Ol2
76:03F-013
76:03F-015
76:03F-024
76-.03F-026
76:03F-027
76.-03F-030
76:03F-033
76:03F-035
76:03F-036
76:03F-041
76:03F-042
76:03F-043
76:03F-046
76:03F-052
76:03F-054
76:03F-055
76:03F-058
76:03F-06Q
76:03F-061
76:03F-062
76:03F-066
76:03F-067
76.-03F-070
76:03F-071
76:03F-072
76:03F-073
76:03F-074
76:03F-076
76:03F-077
76:03F-082
76:03F-083
76:03F-094
76:03F-101
76:03F-110
76:078-010
76:07B-011
76:078-030
Cultivation
76:03F-026
76:05G-002
Crops
76.-02G-078
76:03F-007
76.-03F-029
76; 03F-030
76:05G-005
76:06A-003
76:06A-006
76:08B-003
Curves
76:02F-027
76:04D-005
Cycling Nutrients
76:05G-021
Damages
76:04A-005
Darcy's Law
76:02F-001
76:02F-008
76:02G-050
76:026-052
76:02G-069
76:02G-073
76:02G-082
Data Collections
76:02A-001
76:04A-002
76:048-011
76:056-028
76:05G-011
76:05G-017
76:078-016
76:078-021
Data Processing
76:028-001
76:028-006
76:02F-006
76:02G-013
76:048-008
76:05A-005
76:07C-001
Data Transmission
76:05G-017
Decision Making
76:028-004
76:02E-003
76:03F-019
76:03F-030
76:03F-059
76.-04A-004
76:048-001
76:058-028
76:05G-008
76:06A-001
76:06A-002
76:06A-003
76:06A-004
76:06A-005
76:06A-006
76:06A-007
76:06A-008
76:088-003
Deep Percolation
76:02G-050
76:03F-037
Deep Percolation
(cont.)
76:03F-065
76:058-019
Demonstration Watersheds
76:03F-063
Dendrochronology
76:06F-001
Denitrification
76:02G-043
76:02G-044
76:02G-046
76:02G-047
76:02G-055
76:02G-056
76:02G-109
76:02K-003
76:02K-021
"6:03F-001
76:03F-082
76:058-013
76:058-046
76:050-001
76:078-007
Density
76:02G-082
Deposition (Sediments)
76.-04D-005
Depth
76:02F-009,
76:02G-087i
76:04A-002;
76:048-006
76:048-008
76:05G-009
Desalination
76:02G-024
76:05G-025
76:06A-002
Desalination Plants
76:03A-001
Design
76:028-004
76:02J-008
76:03F-018
76:058-042
76:06A-002
76:06A-005
76:06A-006
76:088-003
Design Criteria
76:03F-003
Desorption
76:02K-001
Dewatering
76:05G-009
275
-------
Diffusion
76:02F-021
76:02G-006
76:02G-085
76:02G-086
76:02G-094
76:02G-098
76:02G-099
76:02G-104
7S:02K-021
76 :05B-027
76:078-020
Diffusivity
76:02G-010
76:02G-030
76:02G-036
76:02G-067
76:02G-070
76:02G-074
76:02G-080
76:02G-085
76:02G-088
76:02G-094
76:02G-095
76:02G-098
76:02G-099
76:02G-100
76:02G-101
76:058-033
Digital Computers
76:02F-006
76:02G-087
Dimensional Analysis
76:02F-020
Discharge Measurement
76:04B-011
76:08B-001
Discharge (Water)
76:028-005
76:020-001
76:02F-001
76:03F-001
76:058-022
76:088-001
Dispersion
76:02F-008
76:058-023
76:058-026
76:056-030
76:056-033
Dissolved Oxygen
76:02G-021
76:058-029
76:058-042
Dissolved Oxygen Analyzers
76:05A-003
Dissolved Solids
76:02F-006
76:02F-034
Dissolved Solids
(cont.)
76:02G-128
76:03C-011
76:030-017
76:040-006
76:05A-002
76:05A-009
76:05C-001
76:076-022
76:078-030
Distribution
76:048-001
Distribution Patterns
76:056-023
76:056-030
Distribution Systems
76:02A-008
76:02E-009
Ditches
76:03F-044
Domestic Wastes
76:050-001
Downstream
76:06A-006
Drag
76:04A-003
Drainage
76:
76:
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
02A-005
02F-001
02F-002
02F-031
02F-032
02G-011
02G-013
02G-069
02G-081
02G-083
02G-087
02G-116
02G-120
03C-011
03C-017
03F-044
03F-045
05A-014
058-004
05B-056
05G-009
05G-025
078-029
07C-004
08G-002
Drainage Area
76.-02E-007
76:02J-010
Drainage Density
76:02E-007
Drainage Districts
76:068-005
Drainage Effects
76:02G-069
76:02G-081
76:02G-120
76.-03F-044
76:03F-045
76:04A-013
76:05A-014
76:068-005
Drainage Engineering
76:02G-120
76:068-005
76:08G-002
Drainage Patterns
(geologic)
76:02E-007
Drainage Practices
76:02F-031
76:02G-069
76:02G-081
76:02G-116
76:02G-120
76:03F-044
76:068-005
76:08G-002
Drainage Programs
76:068-005
Drainage Systems
76:02E-007
76:02F-005
76:02G-120
76:04A-002
76:04A-013
76:05G-009
Drainage Water
76:03C-011
76:03F-045
76:058-004
76:056-054
76:068-005
76:078-006
76:078-015
Drainage Wells
76:05G-009
Drains
76:02F-002
76:02F-005
76:02F-009
76:04A-002
76:04A-013
76:068-005
Drawdown
76:02F-005
76:02F-007
76:02F-012
276
-------
Drawdown
(cont.)
76:02F-016
76:02F-018
76:02F-022
76:02F-029
76:02J-012
76:04B-002
76:04B-007
76:048-008
76:05G-009
Drop Production
76:03F-007
Economics
(cont.)
76:05G-024
76:05G-027
76:06A-003
76:06A-005
76:06A-007
76:06A-008
76:068-002
76:060-001
76:078-025
76:088-003
Drought
76:020-013
Eddies
Effects
Droughts
76:02G-007
76:02G-008
76:03F-052
76:058-037
76:05G-012
Drying
76:02G-003
76:02G-016
76:02G-071
76:02G-083
76:03F-036
Dupuit-Forcheimer Theory
76:02F-005
76:02F-009
76:02F-012
76:02F-025
Dye Concentration
76:058-027
Dye Releases
76:058-027
Dynamic Programming
76:03F-135
76:04A-004
76:058-029
76:05G-004
76:06A-006
Economic Efficiency
76:04A-006
76:06A-006
Economic Impact
76:05G-010
76:060-001
Economics
76:02E-015
76:02J-015
76:03A-001
76:030-012
76:030-014
76:03F-123
76:04A-011
76:048-010
76:05C-001
76:050-004
76:050-005
Effluent Streams
76.-02F-028
Effluents
76:030-001
76:058-014
76:058-016
76:058-027
76:058-042
76 :05B-053
76.-05G-012
Elasticity (Mechanical)
76:02F-007
76:02F-018
Electric Power Costs
76:05G-009
Electrical Conductance
76:020-015
Electrical Conductivity
76:02G-012
Electrical Equipment
76:026-015
Electrical Properties
76:026-001
76:078-003
E1ec tro chemi s try
76:02G-001
Electrodes
76:078-026
Electrolysis
76:05G-009
Elements
76:058-008
Encroachment
76:02L-001
Energy
76:03A-001
76:03E-001
76:03F-102
76:03F-123
76:03F-133
76:048-005
76.-05C-002
76:050-004
76:06E-002
76:078-025
76:088-007
Energy Balance
76:020-007
Energy Budget
76:020-004
76:020-010
76:020-011
76:03F-016
76:058-022
Energy Conversion
76:03F-102
76:050-004
Energy Equation
76:02F-008
Energy Transfer
76:028-006
76:020-005
Engineering
76:03F-028
Environmental Control
76:05G-012
Environmental Effects
76:021-003
Enzymes
76:021-001
Equations
76:02A-001
76:02A-007
76:02A-008
76:028-003
76:028-004
76:028-005
76:028-006
76:02C-001
76:020-003
76:020-006
76:020-011
76.-02E-006
76:02F-002
76:02F-005
76:02F-006
76:02F-007
76:02F-008
76.-02F-009
76:02F-011
76:02F-012
277
-------
Equations
(cont.)
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
:02F-013
:02F-016
:02F-017
:02F-018
:02F-019
:02F-020
:02F-021
:02F-023
:02F-025
:02F-027
:02G-010
:02G-011
:02G-017
:02G-019
:02G-029
:02G-070
:02G-071
:02G-072
:02G-073
.-02G-074
:02G-077
:02G-082
:02G-085
:02G-087
:02G-088
:02G-089
:02G-090
:02G-091
:02G-092
:02G-094
:02G-095
:02G-098
:02G-099
:02G-100
:02G-101
:02G-102
:02J-010
:02J-011
:03F-018
:03F-019
:03F-021
:03F-029
:03F-030
:03F-059
:04A-001
:04A-005
:04A-006
:04B-001
:04B-003
:04B-005
:04B-006
:040-005
:05B-022
:05B-023
:05B-026
:05B-027
:05B-028
05B-029
05B-030
05B-031
05B-032
05B-042
05G-008
06A-001
06A-002
06A-004
Equations
(cont.)
76:06A-005
76:06A-006
76:06A-007
76:06D-001
76.-07B-009
76:088-003
76:08G-001
Equilibrium
76:020-011
76:02F-011
76:02F-019
Equipment
76:02G-004
76:02G-015
76:033-001
76:078-003
Erosion
76:02E-001
76:02J-001
76:02J-002
76:02J-003
76:02J-004
76:02J-005
76:02J-006
76:02J-008
76:02J-015
76:02J-016
76:03F-014
76:03F-101
76:03F-111
76:04A-005
76:040-001
76:040-005
76:05G-002
76:05G-017
Erosion Control
76:02J-011
76;03F-111
76:05G-002
Erosion Rates
76:02J-001
Estimating
76:02B-004
76:020-004
76:020-009
76:03F-016
76:04A-005
76:040-005
76:05B-028
76:05B-040
76:06A-003
76:06A-004
76:06A-006
76:060-001
76:076-003
76:070001
Estimation
76:06A-002
Estaurine Environment
76:021-005
Eutrophication
76:02H-001
76:058-028
Evaluation
76:02A-001
76:058-028
76:08B-003
Evaporation
76:020-002
76:020-003
76:020-005
76:020-011
76:020-012
76:020-013
76:02G-013
76:02G-016
76:02G-025
76:02G-030
76:02G-038
76:02G-078
76:02G-083
76:03F-036
76:03F-040
76:03F-070
76:03F-129
76:05A-014
76:07B-018
Evaporation Pans
76:03F-002
Evapotranspiration
76:02A-003
76:020-002
76:020-004
76:020-006
76:020-007
76:020-008
76:020-009
76:020-010
76:020-012
76:020-013
76:02F-005
76:02G-028
76:02G-041
76:02K-020
76:038-002
76:03C-018
76:03F-011
76:03F-039
76:03F-040
76:03F-047
76:03F-052
76:03F-068
76:03F-070
76:03F-071
76:03F-140
76:03F-141
76:03F-142
76:078-009
76:078-013
76:078-029
278
-------
Fallout
76:02K-012
Fallowing
76:03F-063
Farm Management
76:020-078
76:02J-011
76:040-005
76:05G-005
Farm Ponds
76:05A-003
Farm Wastes
76:02K-006
76:02K-013
76:03F-076
76:056-009
76:05B-011
76:058-040
76:05B-054
76:050-005
76:05G-005
76:07B-015
Farms
76:03F-029
76:03F-059
76:050-010
Faults (Geological)
76:02F-006
76:02F-024
Feasibility
76:06A-001
Federal Government
76:056-015
Federal Water Pollution
Control Act
76:05G-016
Feed Lots
76:058-035
Fertilization
76:020-045
76:02G-055
76:02G-064
76:02G-117
76:021-006
76:021-008
76:02K-021
76:03C-007
76:030-010
76:030-001
76:03F-005
76:03F-006
76:03F-008
76:03F-009
76:03F-013
76:03F-023
76;03F-024
76:03F-Q26
76.-03F-031
Fertilization
(cont.)
76:03F-033
76:03F-035
76:03F-037
76:03F-046
76:03F-049
76:03F-053
76:03F-056
76:03F-057
76:03F-058
76:03F-060
76:03F-061
76:03F-062
76:03F-064
76:03F-065
76:03F-072
76:03F-073
76:03F-074
76:03F-077
76:03F-080
76:03F-081
76:03F-082
76:03F-085
76:03F-086
76:03F-088
76:03F-089
76:03F-090
76:03F-094
76:03F-105
76:03F-110
76:03F-112
76:03F-113
76:03F-115
76:03F-116
76:03F-120
76:03F-126
76:05B-003
76:058-010
76:058-018
76:058-019
76:058-048
76:05G-021
76:07B-010
76:078-011
Fertilizers
76:
76:
76;
76:
76:
76;
76;
76:
76:
76:
76;
76:
76;
76:
76:
76;
76;
76:
76;
76;
76;
02F-003
02G-055
020-117
021-006
021-008
03F-005
03F-008
03F-009
03F-046
03F-049
03F-056
03F-058
03F-060
03F-062
03F-064
03F-069
03F-072
03F-073
03F-077
03F-080
03F-081
Fertilizers
(cont.)
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76;
76:
76:
76:
76:
76:
76:
76:
76;
76:
76;
76:
76:
76:
76:
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
058-
058-
058-
058-
05B-
058-
058-
05B-
058-
05B-
058-
05G-
05G-
050-
050-
050-
-082
-085
-086
•088
•090
•112
•113
•115
•116
•120
126
001
002
003
004
007
010
012
013
019
034
037
001
005
007
014
021
Fescue
76:02K-014
Field Capacity
76:02G-053
76:02K-005
76:02K-020
76:03F-054
Filters
76:03F-117
Filtration
76:03F-117
76:03F-128
76:058-038
76:05G-002
76:078-006
Finite Element Analysis
76:02F-006
76:02F-013
76:02F-014
76:02F-026
76:058-024
76:058-025
76:058-026
76:070-002
Fishing
76:06A-007
Fissures (Geologic)
76:02F-018
76:048-008
279
-------
Flocculation
76:02G-059
Flood Damage
76:04A-005
Flood Forecasting
76:023-005
76:020-013
Flood Frequency
76:02A-007
Flood Irrigation
76:Q2G-045
76:03F-131
76:04A-012
Flood Peak
76:02E-007
Flood Plains
76:020-006
Flood Protection
76:06A-005
Flooflwater
76:02G-021
Floods
Florida
Flow
76:02E-007
76:03F-Q09
76:05B-012
76:02A-004
76:020-001
76:02E-006
76.-02F-002
76:02F-008
76:02F-010
76:02F-013
76:02F-016
76.-02F-017
76:02F-021
76:02G-017
76:02G-019
76:02G-086
76:03F-111
76:04A-003
76:058-024
76:058-025
76:058-030
76:058-033
76:05G-002
76:05G-008
Flow Measure
76:088-008
Flow Measurement
76:088-001
76:08G-001
Flowmeters
76:088-001
Flow Nets
76:02F-028
76:02F-030
Flow Rates
76:020-001
76:020-009
76:02E-004
76:083-001
76:08B-004
76:088-008
Flow Resistance
76:02E-011
76:02F-001
76:02G-006
76:03F-111
76:04A-003
Flow System
76:02F-014
76:02F-016
76:058-024
Fluctuations
76:058-039
Fluid Friction
76:04A-003
Fluid Mechanics
76:02F-021
76:04A-003
Flumes
76:088-008
Fluvial Sediments
76:02J-006
Foliar
76:038-003
76:038-004
Foliar Application
76:038-003
76:038-004
Food Abundance
76:03F-104
Foods
76:03F-104
Forced Drying
76:020-003
Forecasting
76:020-004
76:020-012
76:02E-008
76:02F-026
76:026-018
76:03F-016
Forecasting
(cont.)
76:03F-059
76:04B-006
76:040-005
76:058-032
76:05B-037
76:05B-040
76:06A-003
Foreign Countries
76:056-037
Foreign Projects
76:058-037
Forest Management
76:040-003
Forest Watersheds
76:026-005
76:02K-012
76:040-001
76:056-021
Forests
76:026-005
76:02K-012
Fourier Analysis
76:02E-008
76:058-026
Fracture Permeability
76:02F-010
76:02F-013
76:04B-008
Fractures (6eologic)
76:02F-010
76:02F-018
Free Surfaces
76:02F-001
Freezing
76:07B-006
Freshwater
76:02L-001
76:03A-001
Fungicides
76:026-044
Furrow Irrigation
76:026-069
76:03F-033
76:03F-037
76:03F-043
76:03F-051
76:03F-098
76:03F-109
76:03F-111
76:03F-138
76:04A-012
76:056-002
280
-------
Furrow Irrigation
(cont.) • -
76:05G-021
7.6:088-006
Furrow Systems
76:08B-006
Furrows
76:02G-069
76:03F-111
76:088-006
Gas Chromatography
76:07B-005
Geochemistry
76:02F-024
76:05B-038
Geologic Control
76:02E-Q07
Geology
76:05A-002
76:05A-006
76:056-003
76:05B-036
Geomorphology
76.-02E-Q07
Geophysics
76:02F-027
76:078-003
Georgia
76:02K-019
76:03F-057
76:056-047
76:05B-052
Geothermal Studies
76:030006
Germination
76:021-003
76.-03F-092
Glacial Aquifers
76:058-041
Grain Size
76:020001
Grain Sorghum
76:026-116
76:03F-004
76:03F-036
76:03F-043
76:03F-063
76:03F-066
76:03F-069
76:03F-079
76:03F-098
76:p5B-004
76:05G-007
Grains (Crops)
76:03F-015
Graphical Analysis
76:02A-006
76:02F-005
76:02F-016
76:02F-018
76:02F-020
76:02F-027
76:02G-074
76:04A-002
76:058-023
76:07C-001
Graphical Methods
76.-02G-082
76:07C-001
Grassed Water Ways
76:040001
Grasses
76:020-010
76:021-003
76:021-005
76:03F-096
76:04A-001
Grasslands
76:03F-040
76:03F-105
Gravitational Water Sorption
76:02G-089
Gravity
76:02G-011
76:02G-095
Great Lakes
76:05G-011
Great Plains
76:020-004
76:020-010
76:02G-078
76:03F-016
Greenhouse Experiments
76:02G-119
76:021-008
76:021-009
76:03F-082
76:03F-091
Greenhouses
76:02G-060
76:02G-103
76:02G-111
76:02K-014
Grey-Brown Podzolic Soils
76:02G-003
Groundwater
76:020-009
76:02E-015
76:02F-006
76:02F-008
76:02F-009
76:02F-010
Groundwater
76
76
76
76
76
76
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
:02F
:02F
:02F
:02F
:02F
:02F
:02F
:02F
:02F
:02F
:02F'
:02G-
:02G-
:02G'
:02G-
:02L-
:03B-
:03C-
:03C-
:03F-
:04B-
:04B-
:04B-
:04B-
:04B-
;05A-
:05A-
05A-
058-
058-
058-
058-
058-
058-
058-
058-
058-
05B-
05B-
05B-
058-
05B-
05B-
050-
050-
05G-
05G-
05G-
05G
05G
06F
078
-012
-017
-020
-022
-023
-024
-027
-029
-030
-033
-034
•001
•079
•097
•124
•001
•003
•001
•006
•102
•001
•003
007
009
010
•004
007
010
002
003
007
010
016
017
019
024
025
032
036
037
039
041
045
001
003
003
013
014
019
022
001
029
Groundwater Aquifers
76:02F-026
76.-03F-102
Groundwater Barriers
76:02F-030
Groundwater Basins
76:02F-006
76:02F-025
76:038-003
Groundwater Management
76:02F-034
76:03F-102
281
-------
Groundwater Mining
76:048-010
Hardness (Water)
76:08G-003
History
76:058-028
Groundwater
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76;
Movement
02F-002
02F-005
02F-006
02F-008
02F-009
02F-010
02F-013
02F-016
02F-018
02F-022
02F-023
02F-025
02F-026
02F-028
02G-002
02G-005
02G-006
02G-007
02G-OQ8
02G-076
02G-077
02G-080
02G-083
03F-018
04A-002
05A-007
058-024
05B-025
05G-003 ,
078-009
Groundwater Potential
76:02F-008
76:02G-071
76:02G-079
Groundwater Recharge
76:02F-009
76:02F-020
76:02F-025
76:02F-030
76:02K-020
76:03F-063
76:046-009
76:058-025
76:058-032
76:058-039
Groundwater Resources
76:02F-030
Growth Rates
76:021-002
76:021-004
Growth Stages
76:03F-002
Gypsum
Hail
76:03F-087
76:03F-089
Hawaii
76:02G-005
76-.02G-014
76:02G-024
76:02G-049
76:02J-001
Hazards
76:02G-004
Head Loss
Heat
76:048-007
76:050-002
76:050-004
Heated Water
76:058-031
Heat Flow
76:020-003
76:02G-007
76:02G-008
76:02G-039
76:020-040
76:050-002
Heat Resistance
76:020-008
Heat Transfer
76:020-007
76:020-008
76:02F-013
76:058-022
76:058-031
76:050-004
Heavy Metals
76:02G-027
76:02G-048
76:02G-060
76:02G-062
76:021-001
76:02K-010
76:078-001
Height
76:06A-005
Herbicides
76:02E-002
76:02G-044
76:02G-053
76:03F-119
76:058-006
76:058-012
76:058-014
Heterogeneity
76:02F-005
76:02F-006
76:02F-018
76:02F-027
Homogeneity
76:02F-018
76:02G-017
76:02G-090
76:048-006
Hudson River
76:058-027
76:05G-008
Humid Area
76:02F-032
76:03F-033
Humid Climates
76.-03F-033
Humidity
76:03F-075
76:058-022
76:078-014
Hydraulic Conductivity
76:020-001
76:02F-004
76:02F-005
76:02F-006
76:02F-015
76:02F-019
76:02F-022
76:02F-028
76:02F-029
76:02G-006
76:02G-010
76:02G-014
76:02G-016
76:026-019
76:02G-030
76:02G-037
76:02G-041
76:02G-049
76:02G-052
76:02G-070
76:02G-073
76:02G-079
76:02G-080
76:02G-081
76:02G-087
76-.02G-088
76:02G-090
76:02G-092
76:02G-097
76:02G-120
76:02G-127
76-.03C-015
76:03F-001
76:03F-021
76:04A-002
76:05G-013
76:05G-025
76:070-001
Hydraulic Design
76:088-007
282
-------
Hydraulic Gradient
76:02G-092
76:03F-018
76:05G-009
Hydraulic Models
76:02F-010
Hydraulic Properties
76:02F-016
76:02F-018
76:02G-083
76:03F-018
76:04A-001
Hydraulics
76:02F-010
76:02F-014
76:02F-029
76:02G-017
76:02G-018
76:02G-019
76:02J-012
76:03F-019
76.-04A-001
76:04A-003
76:086-004
76:08B-006
76:08B-007
Hydrodynamics
76:02F-018
Hydroelectric
76:05G-018
Hydroelectric Power
76:04A-004
Hydrogen Ion Concentration
76:05B-038
76:08G-003
Hydrogen Sulfide
76:05G-001
Hydrogeology
76:02F-010
76:02F-026
76:02F-027
76:02F-028
76:02L-001
76:05A-006
76:058-019
76:053-036
Hydrograph Analysis
76:02E-003
Hydrographs
76:02A-003
76:03B-002
76:05G-003
Hydrologic Aspects
76:03A-001
76:03F-059
76:06A-005
76:078-024
Hydrologic Budget
76:020-006
Hydrologic Cycle
76:02A-002
Hydrologic Data
76:02A-001
76:02A-002
76:02A-004
76:020-009
76:02E-003
76:048-011
76:058-030
76:05G-003
76:078-024
Hydrologic Properties
76:02G-005
76:02G-080
76:058-032
Hydrologic Systems
76:02A-008
76:02E-003
Hydrology
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76;
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
02A-001
02A-002
02A-003
02A-004
02A-006
02A-008
028-001
02B-004
02E-003
02E-004
02E-005
02E-006
02E-007
02E-009
02F-010
02F-026
02G-017
03B-002
03B-004
04C-001
04D-003
040-006
058-050
05G-003
05G-015
06A-004
06F-001
078-013
088-003
Hydrolysis
76:02J-009
76:058-038
Hydrostatic Pressure
76:02G-083
Hyetographs
76:028-003
Hysteresis
76:020-003
76:02G-071
76:02G-083
76:02G-093
76:02G-097
76:02G-114
76:02K-008
76:03F-018
Ice
Idaho
76:02A-001
76:02A-002
76:03F-083
76:03F-140
76:03F-141
76:058-008
Illinois
Illite
76:02B-002
76:04A-005
76:05A-002
76:02G-062
Impoundments
76:058-028
Income Distribution
76:05G-012
Income Methodology
76:06A-003
Incubation
76:078-007
Indiana
76:05G-010
Industrial Wastes
76:05G-001
Industries
76:048-005
Infiltration
76:02A-008
76:02E-009
76:02E-012
76:02G-002
76:02G-003
76:02G-005
76:02G-014
76:02G-016
76-.02G-018
76:02G-019
76:02G-025
76:02G-026
76:0?G-029
76:02G-034
76:02G-035
76:02G-037
76:02G-038
76:02G-049
76:02G-071
76-.02G-072
76:02G-079
283
-------
Infiltration
{cont.)
76:
76:
76:
76:
76:
76:
76:
'76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
02G-080
02G-082
02G-083
02G-085
02G-087
02G-091
02G-095
02G-099
02G-100
02G-101
02G-102
02G-118
02G-120
02G-123
02J-005
02K-020
03F-001
03F-065
03F-099
03P-109
03F-137
05B-004
05B-012
05B-024
05B-025
05G-001
05G-013
08B-006
Infiltration Rates
76:02G-029
76:02G-084
76:02G-087
76:02G-089
Infiltrometers
76:02G-005
Inflow
76:030001
76:06A-006
Information Retrieval
76:076-027
Inhibition
76:02E-010
76:020-044
Injection Wells
76:050-003
Inorganic Compounds
76:05D-001
Input-Output Analysis
76:02E-003
76:046-010
76:060-001
Insecticides
76.-02G-022
76:02G-044
76:02G-051
Institutional Constraints
76:06E-002
Institutions
76:05G-020
Instrumentation
76:02G-004
76:02G-005
76:02G-015
76:04C-001
76:05A-003
76.-05G-003
76:07B-003
76:088-001
76:08G-001
Interfaces
76:02F-023
Investment
76:06A-002
Ion Transport
76:02E-004
76:03F-001
Ions
76:02G-066
76:020-122
76:02K-012
76:02K-015
76:02K-018
76:078-004
Iowa
Iron
76:05B-002
76:021-002
76:02K-018
76:03F-013
76.-03F-062
76:03F-067
76:058-055
76:05F-001
76:07B-010
Iron Bacteria
76:05F-001
Iron Oxides
76:02K-019
Irrigated Land
76:03C-001
76:05B-012
76:058-053
Irrigation
76:02E-015
76:02F-032
76:02G-002
76:02G-015
76:020-017
76:02G-037
76:02G-045
Irrigation
(cont.)
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76:
761
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76r
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76
76
76:
76:
76:
:02G-075
:02G-078
:02G-087
:02G-125
:0?-G-127
:02G-128
:02I-010
:03C-Q01
:03C-004
:03C-006
:03C-009
-.03C-014
:03C-015
-.03F-001
:03F-003
:03F-005
-;03F-010
:03F-011
-.03F-018
:03F-033
:03F-034
:03F-037
:03F-038
:03F-043
:03F-044
:03F-046
:03F-051
:03F-055
:03F-078
:03F-079
•03F-084
:03F-090
:03F-094
:03F-095
:03F-096
:03F-D98
:03F-099
:03F-103
:03F-108
:03F-109
:03F-110
:03F-114
r03F-115
:03F-117
03F-118
C3F-119
03F-120
03F-121
03F-122
03F-123
03F-124
03F-125
03F-127
03F-128
03F-131
03F-132
03F-133
< 3F-134
03F-136
03F-138
03F-140
03F-141
03F-142
04A-006
04A-007
04A-008
284
-------
Irrigation
(cont.)
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
04A-
04A-
04A-
04A-
04B-
04B-
05A-
05A-
05B-
05B-
05B-
05B-
05B-
05B-
05B-
050-
05D-
05D-
05D-
05G-
05G-
05G-
05G-
056'
06A-
06A'
06A
06B'
06B'
:06C
07B'
:07B'
07B
07B
:07C
;08B
010
012
•013
•014
•009
•010
•010
•014
•003
•006
•012
•036
•046
•057
•059
•002
-001
-002
-005
-015
•020
-021
-026
-027
-003
-004
-010
-003
-004
-001
-Oil
-015
-025
-027
-003
-004
Irrigation Canals
76:026-017
76:04A-013
76:05A-003
76:05B-006
Irrigation Design
76:03F-003
76.-03F-108
76:03F-137
76:06A-010
76:08B-007
Irrigation Districts
76:04A-010
76:060-001
Irrigation Ditches
76:04A-013
Irrigation Effects
76:02E-015
76:02G-023
76:02G-045
76:02G-075
76:02G-113
76:02G-127
76:026-128
76:021-010
76:030001
Irrigation
(cont.)
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
Effects
:03C-004
:03C-017
:03F-002
.•03F-003
:03F-005
:03F-010
:03F-011
:03F-024
:03F-026
:03F-033
:03F-034
:03F-037
:03F-041
:03F-064
:03F-065
:03F-071
:03F-079
:03F-090
:03F-092
:03F-096
:03F-098
:03F-099
:03F-129
:04A-007
:04A-013
:04B-009
:05A-014
:05B-006
:05B-010
:05B-046
:05B-049
:05B-056
:05B-057
:05B-059
:05C-002
:05D-002
:06A-010
:06B-003
:07B-011
:07B-015
:08B-006
Irrigation Efficiency
76:03C-017
76:030-018
76:03F-001
76:03F-002
76:03F-003
76:03F-024
76:03F-028
76:03F-030
76:03F-099
76:03F-106
76:03F-114
76:03F-118
76:03F-122
76:03F-127
76:03F-130
76:03F-131
76:03F-132
76:03F-133
76:03F-134
76:03F-135
76:03F-136
76:03F-137
76:03F-138
Irrigation Efficiency
(cont.)
76:03F-139
76:03F-141
76:03F-142
76:04A-011
76.-04A-012
76:05A-010
76:05G-001
76:05G-026
76:06A-006
76:070-003
76:08B-007
Irrigation Engineering
76:03F-071
76:03F-103
76:03F-106
76:03F-123
76:06A-010
76:088-001
Irrigation Operation
and Maintenance
76:03F-005
76:056-001
Irrigation Operation
and Management
76:04A-013
Irrigation Practices
76:02G-043
76:030-001
76:030-002
76:030-014
76:030-015
76:03F-001
76:03F-002
76:03F-003
76:03F-010
76:03F-011
76:03F-034
76:03F-038
76:03F-042
76:03F-043
76:03F-046
76:03F-048
76:03F-050
76:03F-051
76:03F-055
76:03F-064
76:03F-065
76:03F-071
76:03F-079
76:03F-081
76:03F-092
76: 03F-094
76:03F-095
76:03F-096
76:03F-099
76:03F-103
76:03F-106
76:03F-107
76:03F-109
76:03F-114
76:03F-115
76:03F-117
76:03F-118
76:03F-119
285
-------
Irrigation Practices
(cont.)
76:03F-120
76:03F-124
76:03F-125
76:03F-127
76:03F-128
76:03F-129
76:03F-131
76:03F-136
76:04A-007
76:04A-012
76.-04A-014
76:05A-008
76:058-049
76:050-005
76:05G-002
76:05G-026
76:05G-027
Irrigation
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
Systems
:03C-001
:03C-002
:03F-001
:03F-003
:03F-005
:03F-010
:03F-019
:03F-028
:03F-033
:03F-038
:03F-044
:03F-048
:03F-050
:03F-071
:03F-078
:03F-103
:03F-106
:03F-108
:03F-109
:03F-110
:03F-114
:03F-117
:03F-119
:03F-122
:03F-127
:03F-129
:03F-130
:03F-132
:03F-133
:03F-136
:03F-137
:03F-138
:03F-141
:03F-142
.-04A-007
:04A-008
:04A-011
:04A-012
:04A-013
:04A-014
:05A-010
:05G-010
:06A-010
:07B-011
:07B-025
Irrigation Systems
(cont.)
76:088-004
76:088-006
Irrigation Water
76:02F-031
76:02F-034
76:026-126
76:030-001
76:03C-006
76:03C-012
76:03C-013
76:03C-014
76:03C-016
76.-03C-017
76:03C-018
76:03F-002
76:03P-009
76:03F-030
76:03F-059
76:03F-081
76:03F-084
76:03F-115
76:03F-117
76:03F-119
76:03F-135
76:03F-138
76:058-049
76:058-054
76:058-059
76:050002
76:050-003
76:050-006
76:05G-027
76:068-003
76:068-004
76:060-002
76:078-029
76:070-003
76:070-004
Irrigation Wells
76:08G-001
Islands
Kansas
76:02F-009
76:03F-060
76:03F-063
Kaolinite
76:02G-062
Kentucky
76:02G-031
Kentucky Bluegrass
76:030-001
76:03F-053
Kinetics
76:02B-005
76:02G-104
76:02G-106
76:02G-109
76:02K-008
Kinetics
(cont.)•
76:058-012
76:050-001
Laboratories
76:07B-002
Laboratory Studies
76:078-012
Laboratory
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
Lake Beds
Tests
.-02F-010
:02G-001
:02G-003
:02G-008
:02G-012
:02G-016
:02G-021
:02G-029
:02G-033
:02G-053
:02G-080
:02G-083
:02G-091
:02G-092
:02G-102
:02G-103
:02J-001
.-03F-018
:04A-001
:04A-002
:04D-001
:07B-002
:07B-003
:07B-004
:07B-006
:07B-008
:08G-001
76:02H-001
Lake Sediments
76:02H-001
Lakes
76:020-011
76:05A-003
Laminar Flow
76:02F-010
Landfills
76:05A-007
76:05B-041
Land Forming
76:03F-063
Land Management
76:02G-081
76:040-005
76:058-019
Land Reclamation
76:02L-001
76:088-003
286
-------
Land Subsidence
76:02F-004
76:02F-015
Land Use
76:056-009
76:053-013
76:05B-037
76:05G-015
Laplaces Equation
76:02F-Q20
76:05B-023
Larae Watersheds
76:02J-010
Latent Heat
76:020-007
76:020-008
Leachate
76:02G-091
76:02K-020
76:05A-006
76:05A-007
76:058-004
76:056-038
76:05G-006
Leachina
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
02E-002
02G-023
02G-043
02G-047
02G-055
02G-056
02G-084
02G-106
02K-004
02K-021
03C-011
03C-013
03C-014
03C-016
03C-018
03F-009
03F-033
03F-047
03F-065
03F-082
03F-090
04A-009
05A-006
05A-010
05A-013
05A-014
05B-001
05B-002
05B-003
05B-004
05B-007
05B-011
05B-012
05B-013
05B-045
05B-053
05B-054
05B-055
Leaching
(cont.)
76:05G-006
' 76:05G-007
76:05G-009
76:050-021
76:05G-025
76:070-004
Lead
Leakage
76:02G-048
76:021-001
76:02F-006
76:02F-007
76:02F-009
76:02F-016
76:02F-022
76:070-001
Least Squares Method
76.-02F-017
Leaves
76:020-001
76:021-001
76:03F-075
76:03F-094
76:07B-018
Legal Aspects
76:03F-028
76:05B-036
76:05G-016
76:06E-001
76:06F-001
Legislation
76:05G-005
76:05G-015
76:05G-016
76:05G-020
76:06E-001
Legumes
76.-03F-073
76:03F-096
76:03F-105
Leontief Models
76:060-001
Lettuce
Levees
Lime
76:03F-092
76:06A-005
76:02G-048
76:02K-004
76.-02K-008
76:03F-006
76:05B-045
76:05G-001
Limestones
76:048-008
76:056-003
Linear Programming
76:02B-002
76:02B-004
76:02E-003
76:03F-019
76:03F-029
76:04A-004
76:048-001
76:050-004
76:05G-010
76:06A-003
76:06A-006
76:068-004
76:060-001
Linings
Loam
Loess
76:03B-001
76:03F-044
76:020-002
76:020-005
76:02G-016
76:020-071
76:020-078
76:020-079
76:020-079
76:058-003
Louisiana
76:02G-021
76:05B-001
LOW Flow
76:058-009
Lumbering
76:040-001
76:040-003
Lysimeters
76:020-002
76:020-005
76:020-007
76:020-008
76:02G-003
76:02K-021
76:03F-011
76:03F-039
76:03F-047
76:03F-070
76:03F-140
76:03F-142
76:05A-014
76:05B-004
76:05B-05S
76:05G-006
76:078-012
Magnesium
76:020-126
76:02K-004
287
-------
Magnesium
(cont.)
76:030011
76:03F-046
76:058-054
76:070-004
76:08G-003
Maintenance
76:05G-017
Maize
76:020-110
Management
76:030-001
76:03F-028
76:03F-030
76:03F-059
76:04A-004
76:046-001
76:05G-008
76:050-016
76:06A-001
76:06A-007
Manganese
Mapping
Maps
76:020-043
76:020-111
76:02K-078
76:03F-013
76:03F-061
76:03F-062
76:03F-067
76:03F-069
76:03F-086
76:05B-043
76:058-055
76:02F-027
76:02F-028
76:078-028
76:02G-009
76:078-028
Marginal Costs
76:05G-008
Markov Processes
76:020-010
76:020-070
76:02G-088
76:05A-005
76:06A-004
Marshes
76:03F-045
Mass Flow
76:02G-117
Mass Transfer
76.-02D-003
76:020-013
76:02F-008
76:02G-035
Mass Transfer
(cont.)
76:058-023
76:058-026
Mathematical Analysis
76:04B-001
Mathematical Models
76:02A-003
76:02A-005
76:02A-006
76:02A-008
76:028-004
76:028-006
76:02D-004
76:020-012
76:020-013
76:02E-005
76:02E-008
76.-02E-009
76:02F-002
76:02F-007
76:02F-017
76:02F-022
76:02F-023
76:02F-025
76:02F-026
76:02F-028
76:02G-003
76:020-007
76:026-008
76:020-011
76:02G-012
76:020-029
76:020-071
76:020-072
76:02G-085
76:020-090
76:02G-091
76:020-092
76:020-093
76:020-096
76:020-097
76:020-098
76:026-099
76:02G-102
76:02G-114
76:038-002
76:03F-Q01
76:03F-016
76:03F-019
76:03F-029
76:03F-059
76:04A-002
76:04A-003
76:04A-004
76:04A-008
76:048-003
76:040-003
76:058-023
76:058-024
76:058-025
76:058-027
76:058-028
76:058-029
76:058-032
76:058-034
76:058-034
Mathematical Models
(cont.)
76:056-037
76:058-042
76:050-003
76 :05G-008
76:05G-010
76:05G-011
76:050-012
76:05G-018
76:06A-002
76:06A-003
76:06A-004
76:06A-005
76:06A-006
76:06A-007
76:060-001
76:078-020
76:08A-005
Mathematical Studies
76:028-001
76:028-002
76:020-003
76:020-011
76:02E-006
76:02F-002
76:02F-007
76:02F-008
76:02F-013
76:02F-016
76:02F-018
76:02F-020
76:020-089
76:02G-090
76:020-091
76:020-094
76:020-099
76:020-100
76:020-101
76:020-121
76:02J-010
76:02J-017
76:058-026
76:058-029
76:058-033
76:06A-008
76:080-001
Mathematics
76:028-001
76;02E-008
76:02F-008
76:020-098
Measurement
76:020-007
76:02F-005
76:020-004
76:020-009
76:048-011
76:05G-003
76:050-017
76;06A-003
76:078-044
76:088-001
76:080-001
288
-------
Membrane Processes
76:056-038
Membranes
Mercury
Metals
76:02G-001
76:038-001
76:02G-027
76:02G-042
76:02K-015
Meteorology
76:02A-002
76:026-006
Methodology
76:02A-001
76:02A-002
76:02B-004
76:02F-004
76:02F-015
76:02G-050
76:02G-074
76:02J-012
76:03F-059
76:04A-005
76:046-001
76:040-005
76:056-030
76:05G-014
76:06A-004
76:06A-005
76:06A-007
76:078-006
76:088-003
Mexico
76:030-012
Michigan
76:05A-006
Microbial Degradation
76:02G-022
76:026-053
Microbial Formation
76:02G-068
Microclimates
76:020-007
Microenvironment
76:026-071
Micrometeorology
76:020-007
76:03F-140
Microorganisms
76:026-106
Mine Wastes
76:056-001
Mineralization
76:02K-013
Mineralogy
76:02J-006
76:05A-002
Mining
76:056-015
76:05G-018
Minnesota
76.-03F-130
Mississippi
76:02E-001
76:02J-002
76:05G-021
Mississippi River
76:02A-006
Mixing
76:02E-004
76:02F-021
76:058-031
76:088-005
Millet
76:020-007
Modeling
76:02E-010
Model Studies
76:02A-002
76:02A-003
76:02A-004
76:02A-005
76:02A-006
76:02A-007
76:02A-008
76:026-003
76:028-005
76:026-006
76:028-007
76:020-002
76:020-004
76:020-007
76:020-008
76:020-009
76:020-012
76:020-013
76:02E-005
76:02E-006
76:02E-008
76:02E-009
76:02E-010
76:02E-012
76:02E-013
76:02E-015
76:02F-004
76:02F-006
76:02F-010
76:02F-014
76:02F-015
76:02F-017
Model Studies
(cont.)
76:02F-022
76:02F-023
76:02F-026
76:02F-028
76:02F-029
76:02G-003
76:026-007
76:02G-008
76:02G-011
76:026-012
76:026-016
76:026-019
76:026-024
76:026-025
76:026-028
76:02G-032
76:02G-037
76:026-041
76:026-065
76:026-072
76:026-073
76:026-077
76:026-085
76:02G-086
76:026-089
76:026-090
76:026-096
76:026-099
76:02G-102
76:026-113
76:026-114
76:026-117
76:026-127
76:02H-001
76:02J-008
76:02J-016
76:02J-017
76:02L-001
76:038-002
76:03F-012
76:03F-016
76:03F-018
76:03F-040
76:03F-060
76:03F-063
76:03F-065
76:03F-068
76:03F-070
76:03F-080
76:03F-097
76:03F-102
76:03F-108
76:03F-133
76:03F-135
76:03F-141
76:04A-003
76:04A-011
76:048-009
76:040-003
76:040-008
76:05A-005
76:05A-008
76:05A-012
76:058-014
76:058-022
289
-------
Model Studies
(cont.)
76:058-024
76:05B-025
76:05B-029
76:058-033
76:058-040
76:058-050
76:058-052
76:058-056
76:058-057
76:058-058
76:050-002
76.-05D-002
76:05G-004
76:05G-034
76:06A-007
76:068-002
76:060-001
76:060-002
76:078-013
76:078-017
76:078-020
76:078-025
76:088-002
76:088-005
Models
76:020-011
Moisture Content
76:02G-019
76:020-074
76:02G-080
76:02G-083
76:02G-086
76:02G-090
76:02G-093'
76.-02G-095
76:02G-097
76:02G-099
76:02G-100
76:02G-101
76:02G-102
76:02K-020
76':03F-001
76:03F-018
Moisture Meters
76:02G-013
Moisture Stress
76:021-003
76:03F-025
76:03F-026
76:03F-049
76:03F-055
76:078-014
Moisture Tension
76:02G-028
76:07B-012
Moisture Uptake
76:03F-025
Momentum Equation
76:02F-008
Momentum Equation
(cont.)
76:02F-021
Monitoring
76:02G-004
76:02K-020
76:03F-019
76:03F-063
76:05A-006
76:058-039
76:058-041
76:05G-016
76:05G-017
Montana
76:06A-006
Monte Carlo Method
76:02G-052
76:05A-005
76:058-032
76:06A-005
Monthly
76:02E-005
Montmorillonite
76:02G-001
76:02G-006
76:02G-112
76:02K-009
76:02K-010
Mountains
Nematodes
76:03F-050
Network Design
76:046-011
Networks
76:028-001
76:028-004
76:028-005
76:04B-003
76:05A-006
Neutron Absorption
76:03F-139
Nevada
76:02F-024
76:02K-020
New Jersey
76:058-013
New Mexico
76:05A-014
76:058-038
76:058-058
76:06A-008
New York
76:078-017
Mulching
76:02G-007
76:02G-008
76:02G-078
76:03F-004
76:03F-036
76:03F-041
76:03F-104
Multiple Purpose Projects
76:04A-004
Multiple-Purpose Reservoirs
76:048-003
Natural Resources
76:05G-015
Natural Streams
76:05A-002
Nebraska
76:02G-023
76:03F-088
76:058-003
76:078-021
76:078-024
Nematicides
76:03F-050
Nickel
76:058-009
76:058-011
76:058-040
76:05G-008
76:058-008
76:078-001
Nitrates
76:
76;
76 i
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76;
76:
76:
76:
76
76:
02F-003
02G-021
02G-046
02G-047
02G-055
02G-057
02G-066
02G-086
02G-117
021-009
02K-003
03F-084
058-001
058-002
058-003
058-004
058-005
058-013
058-037
058-046
058-047
05D-001
05G-003
05G-005
05G-006
05G-014
07B-006
078-015
290
-------
Nitrification
76:02G-020
76:02G-046
76:02G-056
76:020-066
76:02K-016
76:03F-057
76:03F-085
76:05G-021
Nitrogen
(cont. }
Nitrites
76:02G-061
76:02G-066
76:02K-116
76:02K-H7
76:03F-001
76:03F-027
76:03F-082
76:053-013
76:05B-032
76:056-047
76:05G-007
Nitrogen
76:
76
76;
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76:
76
76,
76:
76;
76;
76;
76;
76;
76;
76:
76:
76;
76;
76.
02D-
02E-
02E-
020-
02G-
02G-
02G-
02G-
02G-
02G-
02G-
02G-
02G-
020-
021-
021-
021-
02J-
02K-
02K-
02K-
03C-
03C-
03D-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
•010
•001
•014
•023
•043
•045
•046
•047
•056
•057
•064
•086
•106
•117
•004
•006
•008
•002
•003
•016
•021
•007
•010
•001
•006
•008
•009
•012
•015
•023
•024
•032
•035
•041
•042
•049
053
056
058
064
065
069
072
073
074
076
76:03F-077
76:03F-080
76:03F-083
76:03F-085
76;03F-087
76.-Q3F-088
76:Q3F-Q90
76:03F-Q93
76;03F-094
76;Q3F-105
76:Q3FT-110
76.-Q3F-112
76;03F-116
76:Q3F-126
76:056-001
76:058-002
76:058-003
76:053-005
76:053-007
76:053-010
76:053-013
76:053-018
76:053-019
76:053-021
76:053-037
76:053-040
76:053-050
76:053-056
76:056-007
76:05G-021
76:073-002
76:073-006
76:073-007
Nitrogen Compounds
76:053-001
76:058-002
76:053-004
76:050-007
Nitrogen Crop Response
76:03F-057
Nitrogen Cycle
76:053-053
North Carolina
76:02K-012
76:063-003
76:063-004
North Dakota
76:03F-084
76:05G-003
Nuclear Explosions
76:053-015
Nuclear Energy
76:050-018
Nuclear Meters
76:02K-020
Nuclear Moisture Meters
76:02G-004
Nuclear Wastes
76:053-015
Numerical Analysis
76.-02A-005
76:020-003
76:02F-005
76:02F-013
76:02F-014
76:02F-026
76:02G-011
76:020-018
76:02G-025
76:02G-073
76:020-074
76:02G-092
76:020-100
76:043-007
76:043-008
76:046-009
76:053-026
76:053-031
Nutrient Removal
76:053-001
76:053-002
76:053-004
76:05G-007
Nutrient Requirements
76:020-086
76:03F-023
76:03F-027
Nutrients
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76;
76;
76
76
76
02D
02E
02E
02E
020
02G
020-
020-
020-
021'
021-
021-
021-
02J-
02J-
;03C-
:03C-
;03D-
:03F-
:03F-
:03F-
:03F-
:03F-
:03F-
:03F-
:03F-
:03F-
:03F'
:03F-
:03F'
:03F
:03F
:03F
:03F
:03F
001
001
010
014
045
058
064
107
117
002
004
006
009
002
009
004
007
001
005
006
•008
•009
•012
•013
•031
•032
•033
•035
•041
-042
-046
-049
-053
-056
-057
291
-------
Nutrients
(cont.)
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76
76:
76;
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76;
76:
76:
76:
Oats
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
05B-
05B-
05B-
05B-
05B-
:05B-
05B-
:05B-
:05B-
05B-
:05B-
:05B-
05B-
05B-
05G-
05G-
05G-
06A-
07B-
07B-
07B-
060
061
062
064
069
072
074
076
077
080
081
083
•085
086
•110
•112
113
115
116
•120
•126
•002
•004
•007
•010
•013
•021
•034
•040
•048
•050
•052
•053
•055
•056
•005
•007
•021
009
•007
010
•020
Oil Shale
76:06E-002
Oil Wastes
76:05B-036
76:02G-111
76:021-004
76:05G-007
Observation Wells
76:02J-012
76:048-008
76:04B-011
76:05A-006
Ohio
76:02J-006
76:03F-007
76:05B-019
Ohio River
76:02A-006
OiJ Fields
76:058-039
Oil Industry
76:056-036
Oil Wells
76:058-036
Oklahoma
76:02F-028
76:05B-036
On-Site Data Collections
76:028-002
76:020-004
76:02F-011
76:02K-012
76:03F-016
On-Site Investigations
76:028-002
76:020-010
76:020-011
76:02F-028
76:02G-005
76:02G-007
76:02G-008
76:02G-009
76:02G-084
76:02G-096
76:058-001
76:05B-037
76:05G-003
76:05G-009
On-Site Tests
76:02G-018
76:04A-002
76:088-001
76:078-003
Onions
76:030-009
76:03F-092
Open Channel Flow
76:02J-013
Open Channels
76:02J-013
76:08B-008
Operating Costs
76:04B-005
Operations
76:03F-003
76:03F-028
76:05G-017
76:05G-020
Operations Research
76:03F-019
76-.03F-030
76:04A-004
76:04A-006
76:06A-001
Optimization
Optimum
Plans
Oranges
Orchards
Oregon
76.-02A-005
76:028-004
76:02E-015
76:03F-019
76:03F-028
76:03F-030
76:03F-059
76:03F-108
76:03F-135
76:04A-004
76:04A-006
76:04A-011
76:04B-001
76:058-029
76:058-042
76:05G-008
76:05G-018
76:056-024
76:06A-002
76:06A-003
76:06A-005
76.-06A-006
76.-06A-007
76:060-002
76:088-003
Development
76:04A-003
76:05G-012
76:03C-004
76:03C-004
76:03C-012
76:03F-034
76:03F-129
76:03F-132
76:03F-136
76:03F-142
76:078-030
76:028-002
76:03F-034
76:03F-086
76:06C-001
Organic Comoounds
76^:058-043
76:050-001
Organic Matter
76:02G-054
76:02G-078
76:02G-105
76:02G-111
76:021-002
76:02J-014
76:02K-006
76:02K-013
76:02K-015
76:03F-054
76:03F-093
76;05B-020
76:05B-029
292
-------
Organic Matter
(cent.)
76:058-046
' 76:050-007
Orifices
76:086-001
76:08G-001
Osmotic Pressure
76:021-003
Overland Plow
76:02A-008
76:02E-006
76:02E-009
76:02G-041
76:04A-008
Oxidation-Reduction Potential
76:05A-007
Peat
76:02G-054
Oxygen
76:02G-046
Oxygen Isotopes
76:02E-004
Pacific Ocean
76:02B-002
Parametric Hydrology
76:02A-005
76:02A-007
76:02E-006
Particle Size
76:02F-028
76:02G-107
76:02J-008
76:02J-014
Pastures
76:03F-093
Path of Pollutants
76:02G-086
76:05A-007
76:05B-004
76:05B-012
76:058-023
76:058-024
76:058-025
76:058-027
76:058-028
76:058-035
76:058-039
76:058-041
76:058-042
76:05G-014
76:05G-021
Peaches
Peanuts
Penalties (Legal)
76:05G-016
Pennsylvania
76:02G-013
76:058-022
Percolating Water
76:02G-002
Percolation
76:02F-025
76:02G-002
76:02G-005
76:02G-010
76:02G-102
76:058-002
76:058-004
76:058-053
Performance
76:02A-005
Permeability
76:02F-007
76:02F-016
76:02F-019
76:02F-022
76:02G-006
76:02G-017
76:02G-080
76:02G-082
76:02G-087
76:02G-096
76:02G-100
76:048-002
76:048-008
76:05F-001
Permeameters
76:02F-028
Permits
76:05G-016
76:06E-002
76:03F-129
76:03F-142
76:03F-087
Persistence
76:02E-005
76:02G-022
Pervious Soils
76:02G-102
Pesticide Residues
76:02G-053
Pesticides
76:02G-022
76:02G-044
76:02G-053
76:058-014
76:058-048
76:058-050
76:058-052
76:06A-009
Phosphates
76:02G-063
76:02J-009
76:02K-002
76.-02K-008
76-.03F-001
76:03F-027
76:058-001
76:058-008
76:058-013
76:053-045
Phosphorus
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
02E-
02E-
02G-
02G-
02G-
02H-
021-
021-
021-
021-
02J-
02J-
02K-
02K-
02K-
02K-
03C-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
03F-
05A-
058-
058-
058-
058-
058-
05B-
078-
07B-
-001
-014
•048
•058
•060
•001
•001
•002
•004
•009
•002
009
•005
006
•007
013
010
005
012
013
042
046
067
069
073
076
081
093
120
001
009
021
034
040
045
050
006
012
Phosphorus Compounds
76:058-001
Photosynthesis
76:02E-010
76:03F-075
76:078-021
Phreatic Lines
76:02G-017
Phreatophytes
76:03B-003
76:038-004
293
-------
Physical Properties
76:02A-001
76:02G-003
76:02G-006
76:020-093
76:076-003
Piezometers
76:058-036
Pine Trees
76:040001
76:05G-021
Pipe Flow
76:088-001
76:088-007
Pipelines
Pipes
76:03F-108
76:088-007
76:08G-001
Piping Systems
76:03F-108
Pit Recharge
76:02F-025
Planning
76:03F-019
76:03F-028
76:04A-004
76:05A-006
76:05G-015
76:06A-004
76:06A-006
76:06A-008
76:06A-011
76:060-001
76:06E-002
Plant Growth
76:021-004
76:03F-014
76:03F-023
Planting Management
76:021-003
76:03F-023
76:03F-024
Plant Physiology
76:026-075
Plant Populations
76:03F-036
76:03F-058
Plant Tissues
76:02G-075
76:02G-092
76:03F-027
Plastic Pipes
76:05G-009
Plastics
76:038-001
76:05A-003
Political Aspects
76:05G-020
76:06A-001
Pollutant Identification
76:02G-050
76:05A-003
76:05A-004
76:058-027
76:058-051
76:05G-021
76:078-006
Pollutants
76:02K-020
76:05A-005
76:05A-006
76:05A-007
76:058-007
76:058-010
76:058-017
76:058-025
76:058-029
76:058-033
76:058-036
76:058-037
76:058-039
76:058-051
76:06A-009
Pollution
76:058-018
76:058-039
Pollution Abatement
76:058-051
76:056-001
76:056-008
76:06A-001
76:06E-001
Ponding
76:026-014
76:02G-082
76:026-096
Ponderosa Pinetrees
76:04C-001
Ponds
76:020-011
76:05A-003
Pore Pressure
76:026-082
76:026-089
76:026-090
76:026-097
76:02J-014
Pores
76:02F-025
76:026-024
76:02G-038
Pores
(cont.}
76:026-071
76:026-081
Pore Water
76:02F-008
76:026-024
76:026-071
76:026-084
76:026-093
76:026-097
76:02J-003
Porosity
76:02F-005
76:02F-027
76:02G-002
76:026-018
76:026-030
76:026-038
76:02G-081
76:026-082
76:026-090
76:04A-002
Porous Media
76:02F-001
76:02F-008
76:02F-013
76:02F-018
76:02F-020
76:02F-021
76:026-006
76:026-029
76:02G-035
76:026-072
76:02G-073
76:02G-083
76:026-090
76:026-097
76:02G-102
76:058-023
Portable Water
76:08G-003
Potash
76:058-001
Potassium
76:026-023
76:026-031
76:026-062
76:026-107
76:021-009
76:02K-001
76:03F-009
76:03F-012
76:03F-031
76:03F-042
76:03F-069
76:03F-073
76:058-054
76:078-012
76:078-020
Potassium Compounds
76:058-001
294
-------
Potatoes
76:03F-049
76:03F-055
76:03F-065
76-.03F-070
76:03F-086
76:03F-090
76:03F-095
Potential Flow
76:020-005
76:02F-013
76:02F-025
76:02G-092
Potential Water Supply
76:03F-Q63
Potentiometric Level
76:02F-009
76:02F-Q19
76:02F-028
76:05B-036
Prairie Soils
76:02D-010
Precipitation
76:02B-004
76:02B-007
76:02B-OQ8
76:02E-001
76:02F-003
76:02J-004
76:02K-001
Precipitation (Atmospheric)
76:02A-Q03
76:02B-Q01
76:02B-002
76:028-003
76:02E-003
76:02E-004
76:02G-012
76:020-014
76:02G-078
76:02K-012
76:036-002
76:Q5B-039
Preservation
76:078-006
Pressure
76:02G-001
Pressure Head
76:02F-012
76:02G-018
76:02G-019
76:026-073
76:02G-074
76:02G-083
76:02G-089
76:03F-018
Probability
76:05B-032
76:06A-003
76:06A-004
Raindrops
76:02J-003
Profiles
Profit
76:02G-011
76:03F-029
Project Feasibility
76:06A-010
Project Planning
76:06A-010
Projects
76:06A-005
76:06A-007
76:06A-010
Proteins
76:021-001
Pumping
Prices
Pricing
76:05G-012
76:03F-029
76:060-001
76:060-002
76:02F-007
76:02F-018
76:02F-022
76:02J-012
76.-02L-001
76:04A-006
76.-04B-001
76:048-002
76.-04B-007
76:046-008
76:048-009
76:05G-009
76:05G-014
Pumping Plants
76:048-009
Pump Testing
76:02F-028
76:070-001
Queueing Theory
76:03F-019
Radiation
76:028-006
76:02D-011
76:02G-004
76:05B-002
76:058-031
76:076-014
Radioactivitv
76:020-004
Rain
76:02E-012
76:02K-012
76:03F-039
Rain Water
76:02F-003
Rainfall
76
76
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
:02A
:02A
;02A
:02A
:02B'
:02B-
02B-
02B-
028'
028-
02B-
02E-
02E-
02G-
02G-
02J-
02J-
02J-
02J-
02K-
03B-
030-
03F-
03F-
03F-
05B-
•002
•003
•006
•008
•001
•002
•003
•004
•005
•007
008
012
013
002
014
001
003
004
005
012
002
019
029
039
063
039
Rainfall Disposition
76:028-007
Rainfall Intensity
76:026-003
76:02E-012
Rainfall Simulators
76:028-007
76:02F-012
76:02J-005
Rainfall-Runoff
Relationships
76:02A-006
76:02A-007
76:02A-008
76:028-005
76:02E-006
76:02E-012
76:020-014
76:02J-005
Range Grasses
76:020-004
76:03F-016
Rangelands
76:03F-091
Ranges
76:020-004
76:03F-016
295
-------
Reaeration
76:058-029
Recharge
76:02F-014
76:02F-020
76:02L-001
76:03F-063
76:048-011
76:058-025
Reclamation
76:050-009
Recreation
76:04A-005
76:06A-008
Reduction (Chemical)
76:05A-007
76:058-038
Reforestation
76:040-003
Regional Analysis
76:06A-002
Regions
76:05A-002
Regression Analysis
76:02A-002
76:02E-008
76:02J-008
76:02J-010
76:048-006
Regulation
76:05G-008
76:050-016
76:05G-017
Reinforcement
76:038-001
Reliability
76:06A-006
Remote Sensing
76:020-006
76:03F-003
76:078-013
Reynolds Number
76:04A-001
Repellents
76:040-001
Research
76:05G-010
Reservoir Design
76:02E-013
Reservoir Operation
76:04A-006
76:048-003
Reservoir Releases
76:06A-006
Reservoir Storage
76:04A-008
76:048-003
76:06A-006
Reservoirs
76:02J-002
76:02J-010
76:03F-029
76:04A-004
76:04A-005
76:040-005
76:06A-004
Resistance Networks
76:02F-021
76:02F-019
76:048-007
Resistivity
76:02F-027
76:05B-041
76:078-003
Respiration
76:021-001
Return Flow
76:
76;
76;
76;
76;
76;
76;
76
76;
76;
76;
76:
76:
76:
76:
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
02E-011
02E-014
02F-031
02G-128
03C-012
03F-043
03F-045
03F-138
05A-014
05A-016
058-043
058-047
05B-048
058-049
05B-050
058-052
058-053
058-054
058-056
058-057
05G-002
05G-006
05G-022
058-027
06A-011
06E-001
078-022
07B-024
Reynolds Number
76:02F-001
Rhode Island
76:058-041
Rice
76:02G-045
76:02G-119
(cont.)
76:03F-028
76:03F-046
76:03F-067
76:03F-077
Rill Erosion
76-.03F-011
Rio Grande River
76:05G-006
76:05G-009
Risks
76:02A-007
76:03F-019
76:058-028
76:06A-003
76:06A-005
76:088-003
River Basin Development
76:06A-007
76-.06F-001
River Basins
76:048-003
76:040-006
76:05A-010
76:06A-004
River Flow
76:078-022
River Systems
" 76:026-124
76:030-013
76:040-006
76:05A-042
76.-05B-042
Rivers
76:02E-005
76:02E-008
76:05A-002
76:058-031
76:058-033
76:058-043
76:07B-022
Rock Properties
76:02F-018
Rocks
76:02F-010
76:026-007
76:026-008
Root Development
76:026-118
76:02G-119
76:021-004
76:03F-031
76:03F-049
76t03F-080
76:03F-097
76:058-044
76:058-046
296
-------
Root Distribution
76:03F-098
Root Systems
76;02G-086
76:02G-092
76:02G-110
76:020-114
76;03F-023
76:03F-047
7S:05B-044
Root Zone
Roots
76:020-001
76:02G-023
76;02G-028
76:02G-092
76;02G-096
76:02G-114
76:02G-128
76:030-001
76:03F-025
76:03F-027
76:05A-003
76:058-004
76:056-016
76:05B-044
76:05G-009
76:021-008
Roughness (Hydraulic)
76:04A-001
76:04A-003
Roughness Coefficient
76:04A-001
Runoff
76:02A-003
76:02A-006
76:02A-008
76:02B-005
76:020-001
76:02E-001
76:02E-002
76:02E-004
76:02E-005
76:02E-006
76:02E-011
76:02G-013
76:02G-014
76:02J-001
76:02J-010
76:02G-011
76:03B-002
76:030-012
76:04A-009
76:04D-003
76:05B-001
76:05B-002
76:05B-004
76-.05B-018
76:05B-035
76:05B-047
76:058-050
76:05B-052
76:05G-002
Runoff
(cont,)
76:05G-007
76:05G--015
76:06B~002
76:078-024
Runoff Forecasting
76:02B-005
76:02E-003
Rye Grass
76:03F-096
Safety
76:02G-004
Sagebrush
76:05B-008
Saline Soils
76:02F-034
76:02G-009
76:02G-012
76:02G-015
76:02G-124
76:02G-127
76:030-002
76:030-005
76:030-007
76:030-010
76:030-012
76:030-014
76-.03C-017
76:03F-072
76:03F-091
76:04A-009
76:05A-013
76:058-044
76:05B-048
76:05B-059
76:050-002
76:05G-022
76:05G-025
76:05G-026
76:05G-027
76:078-003
76:078-023
76:076-026
76:078-028
76:07B-029
76:070-004
Saline Water
76:02G-126
76:026-128
76:021-010
76:02L-001
76:030-001
76:030-002
76:030-004
76:030-009
76:030-011
76:030-012
76:030-013
76:030-015
76:030-016
76:030-017
76:030-018
Saline Water
(cont.)
76:030-019
76:05A-010
76:05A-012
76:05A-013
76:056-048
76:050-001
76:050-002
76:050-003
76:05G-026
76:05G-027
76:078-003
76:07B-030
76:070-003
Saline Water-Freshwater
Interfaces
76:02F-009
76-.02F-023
Saline Water Intrusion
76:02F-023
76:02L-001
Saline Water Systems
76:02L-001
76:050-002
Salinity
76:02E-015
76:02F-027
76;02F-031
76:02F-034
76:020-009
76:02G-012
76:02G-015
76-.02G-124
76:020-127
76:02G-128
76:021-010
76:02K-018
76:03A-001
76:030-001
76:030-002
76:030-004
76:030-005
76:030-007
76:030-008
76:030-009
76:030-010
76:030-011
76:030-013
76:030-014
76:030-017
76:030-018
76:030-019
76:03F-072
76J03F-091
76:04A-009
76:04A-013
76:040-006
76:05A-008
76i05A-010
76s05A-012
76:05A-013
76:058-016
76:058-044
76:058-048
297
-------
Salinity
(cont.)
76:058-056
76:0^6-057
76:058-058
76:05C-002
76:050-003
76:05G-018
76:05G-020
76:05G-022
76:05G-026
76:05G-027
76:07B-003
76:07B-015
76:07B-023
76:07B-026
76:07B-028
76:076-029
76:07B-030
76-.07C-003
76:07C-004
Salt Balance
76:02G-124
76:03C-001
76:03C-018
76:05B-016
76:050-002
76:05G-006
76:078-029
76:070-004
Salt Marshes
76:021-005
Salt Tolerance
76:030-005
76:030-008
76:03F-091
Salt Water Intrusion
76:05G-019
Salts
76:02E-015
76:02G-001
76:020-009
76:02G-015
76:02G-027
76:02G-032
76:02G-050
76:020-084
76:02G-124
76:02G-127
76:02K-009
76-.02K-018
76:030-011
76:030-013
76;03C-015
76:030-016
76:030-019
76:04A-009
76:05A-008
76:058-016
76:058-048
76:058-055
76:058-059
76:050-002
76:05G-020
Salts
(cont
Samplers
Sampling
.)
76:05G-022
76:05G-027
76:078-003
76:07B-028
76:078-029
76:070-004
76:058-004
76:028-004
76:02E-001
76:02E-004
76:02G-057
76:02G-096
76:026-103
76:02J-006
76:02K-013
76:03F-035
76:05A-003
76:05A-004
76;05A-006
76:058-009
76:05B-015
76:058-019
76:058-028
76:058-039
76:058-049
76:05G-014
76:05G-021
76:078-004
76:078-006
76:078-015
76:078-018
76:078-027
76:078-029
Sand Aquifers
76:02F-027
76:048-007
Sands
76:020-001
76:02F-027
76:02G-011
76:020-071
76:02J-003
76-.03F--001
76;03F-037
76:05B-012
Sandstones
76-.02F-027
76:05B-037
Sandy Soil
76:058-045
Satellites
76:07B-013
Saturated Flow
76:02F-005
76:02G-108
76-.05B-023
Saturated Soils
76:02G-032
Saturation
76:02G-071
76:02G-082
76:02G-090
76:02G-109
Scaling
76:080-003
Scheduling
76:020-075
76:03F-019
76:03F-078
76:03F-139
76:03F-141
76:03F-142
Seasonal
76:02A-004
76:02B-002
76:02K-012
Sea Water
76:02F-023
Sedimentation
76:02E-013
76:02H-001
76:02J-002
76:02J-009
76:02J--013
76:02J-016
76:02J-017
76:040-001
76:05B-052
76:05G-015
76:05G-016
76:068-002
Sedimentation Rates
76:040-005
Sediment Control
76:02E-011
76:02J-013
76i02JV017
76:050-002
Sediment Discharge
76;05B-002
Sediment Transport
76:06A-009
Sediment Yield
76i02J-008
76:02J-010
76;02J-011
76:02J-013
76:040-005
76:05G-005
Sediments
76:02E-011
76:02E-013
76-.02H-001
298
-------
Sediments
(cont.)
76:02J-006
76:02J-009
76-.02J-013
76:02J-014
76:02J-016
76:0!2ar-017
76-.04A-005
76:05B-008
76:05B-009
76:05B-048
76:05B-052
76:056-005
76:05G-015
76:06A-009
76:07B-006
Shrinkage
Seeds
Seepage
76:03F-092
76:02A-003
76:02F-001
76:02F-028
76:02F-031
76:02G-017
76:02G-028
76:020-050
76:02G-089
76:02G-108
76:02L-001
76:03B-001
76:03B-002
76:04A-010
76:05A-009
76:05G-003
76:05G-026
Seepage Control
76:05G-003
Self-Purification
76:05B-029
Selinium
76':02G-068
Semiarid Climates
76:021-003
76:03F-042
Septic Tanks
76:050-001
Sewage
76:05B-042
Sewage Treatement
76:05D-001
Shales
76:05E-003
76:05B-008
Sheet Erosion
76:02J-011
Shrubs
Silts
76:02G-093
76:021-003
76:02G-071
76:02G-079
76:056-015
Simulated Rainfall
76;02E-002
76:026-014
76:02J-001
Simulation
76:05B-050
Simulation Analysis
76:02A-007
76:028^007
76;02E-012
76:02E-015
76-.02F-004
76:02F-015
76:02G-025
76:026>-028
76:02G-127
76:02J-016
76:02J-017
76:03F-012
76;03F-019
76:03F-030
76:03F-060
76,-03F-080
76:03F-133
76:03F-141
76:04A-003
76:04A-008
76:04A-011
76:05A-008
76:05A-009
76:05A-012
76:05B-028
76i05B-042
76:05B-052
76:05B-056
76:05B-057
76:05B-058
76:05C-002
76:056-004
76:056-006
76:056-012
76:06A-004
76:06A-005
76:06A-006
76:06A-007
76:060-002
76:07B-020
76;07B-025
76:088-005
Size
76:05G-010
Size Sites
76:03A-001
Small Watersheds
76:02J-010
76:04A-006
Snow
76:02A-001
76:02A-002
76:02C-001
76:02K-012
Snowmelt
76:056-050
76:05B-052
Social Needs
76:06A-003
Social Values
76:06A-008
76:021-010
76:021^018
76)03Cr-014
Sodium
76:05A-013
76:05B-054
76;07B-029
76:07C-004
76:08G-003
Sodium Chloride
76:02F-027
76s02G-001
Soil Aggregates
76:02G-038
Soil Amendments
76:02G-062
Soil Analysis
76:03F^057
76j05G-006
Soil Chemical Properties
76:02G-031
76-.02G-033
76:02G-059
76:02G-104
76:02G-107
76i02G-lll
76:03C-001
76:03C-015
76:05B-003
76s07BT-007
Soil Chemistry
76:02G-031
76:02G-033
76:02G-035
76:02G-059
76:02G-061
76:02G-065
76:026-068
76:02G-091
76:02G-103
76:02G-107
76:026-112
299
-------
Soil Chemistry
(cont.)
76.-02G-122
76:020-126
76:02K-001
76:058-004
76:078-001
Soil Classification
76:02G-018
Soil Compaction
76:03F-54
Soil Conservation
76:02J-011
76:040-005
76:05B-002
Soil Contamination
76:058-003
Soil Environment
76:021-004
Soil Erosion
76:02J-001
76:02J-006
76:02J-011
76:02J-015
76:03F-101
76:03F-105
76:040-005
76:05B-002
76:05B-05Q
76:050-007
Soil Horizons
76:020-018
76:020-079
76:020-096
76:05B-015
Soil Investigations
76:02G-021
76:020-022
76:020-023
76:020-024
76:020-025
76:020-026
76:020-030
76:020-031
76:020-033
76:020-034
76:020-036
76:020-038
76:020-039
76:020-040
76:020-042
76:020-043
76:020-045
76:020-046
76:020-047
76:020-048
76:020-051
76:020-052
76:020-053
76:020-054
76:020-055
76:020-056
76:020-057
Soil Investingations
(cont.)
76:020-059
' 76:020-061
76:020-063
76:020-065
76:020-066
76:020-067
76:020-068
76:020-079
76:020-103
76J02G-104
76:020-105
76s02G-106
76:020-107
76:020-111
76:020-112
76:020-118
76:021-008
76:02J-002
76:02J-004
76:02J-014
76:02K-001
76:02K-004
76:02K-005
76:02K-006
76;02K-007
76:02K-008
76:02K-010
76:02K-013
76:02K-014
76:02K-015
76;02K-016
76:02K-017
76:02K-018
76:02K-019
76:03F-031
76:03F-084
76;03F-085
76:03F-087
76:03F-093
76:03F-100
76:056-015
76:053-017
76:058-020
76:058-034
76:05B-045
76:078-001
76:078-002
76:078-004
76:078-005
76:078-007
76:078-008
76:078-010
76:078-012
76:078-015
Soil Management
76:021-004
76:03C-001
76:03F-026
Soil Mechanics
76:058-053
Soil Moisture
76:02A-005
76:02D-002
76:02E-013
Soil Moisture
Ccont.)
76:02G-002
76:02G-003
76:020-004
76:020-007
76:020-008
76:02G-010
76:020-013
76:02G-016
76:020-018
76:020-025
76:02G-026
76:020-034
76:020-037
76:020-038
76:020-041
76:020-042
76:020-054
76:020-067
76:020-070
76i02G-071
76:020-075
76:02g-079
76;02G-080
76i02G-083
76:020-085
76i02G-088
76:020-093
76:020^095
76s02G-096
76:02G-099
76:02G-102
76s02G-lQ8
76:020-113
76:020-114
76i02G-123
76:021-003
76:02K-016
76:03C-OQ4
76«03C-009
76s03F-003
76:03F-011
76;03F-032
76:03F-040
76i03F-049
76:03F-054
76:03F-063
76:03F-065
76s03F-067
76)03F-069
76i03F~076
76;03F-078
76:03F-079
76j03F-084
76i03F-085
76:03F-088
76t03F-095
76i03F-097
76:03F-100
76:03F-110
76:03F-121
76i03F-139
76:03F-142
76:058-020
76:058-044
76i07B-012
76:078-014
76:078-016
300
-------
Soil Moisture Meters
76:02G-003
76:02G-083
Soil Moisture Movement
76:020-099
76:03F-003
Soil Physical Properties
76:020-001
76:020-005
76:020-081
76:020-085
76:020-102
76:020-118
76:020-119
76:020-127
76:030015
76:03F-054
76:07B-004
Soil Physics
76:020-018
76:020-019
76:020-029
76:020-072
Soil Profiles
76:02E-002
76:020-018
76:020-047
76:020-084
76:03F-018
76:03F-025
76:03F-031
76:058-015
76:058-017
76:07B-005
Soil Properties
76:020-003
76:020-005
76:020-016
76:020-025
76:020-029
76:020-030
76:020-033
76:020-034
76:020-035
76:020-036
76:020-038
76:020-039
76:020-041
76:020-054
76:020-055
76:020-057
76:020-059
76:020-061
76:020-063
76:020-065
76:020-068
76:020-072
76:020-074
76:020-078
76:020-079
76:020-080
76:020-081
76:020-082
76:020-087
Soil Properties
(cont.)
76:020-089
i 76:020-090
76:020-103
76:020-104
76:020-105
76:020-107
76:020-108
76:020-109
76:020-111
76:020-112
76:020-118
76:020-120
76:020-122
76:020-123
76:020-124
76:020-126
76:02J-004
76:02K-002
76:02K-004
76:02K-007
76:02K-008
76:02K-013
76:02K-014
76:02K-015
76:02K-017
76:02K-018
76:02K-019
76:03F-004
76:03F-018
76:03F-031
76:03F-054
76:03F-085
76:050-025
76:07B-001
76:078-002
76:07B-005
76:07B-008
Soil Salinity
76:05B-016
76:05B-055
76:078-003
76:07B-023
Soil Science
76:020-001
76:020-003
76:020-004
76:020-005
76:020-006
76:020-007
76:020-008
76:020-009
76:020-011
76:020-012
76:020-013
76:020-015
76:020-016
76:020-078
76:020-079
76:020-093
76:020-095
76:020-096
76:020-097
76:020-099
76:04D-001
Soil Stabilization
76:040-001
Soil Sterilants
76:020-061
Soil Strength
76:020-081
Soil Surfaces
76:020-005
76:020-091
Soil Tolerance
76:050-020
Soil Temperature
76:020-040
76:020-041
76:020-042
76:020-085
76:021-004
76i03F-041
76:050-002
76:050-004
Soil Tests
76:02J-Q04
76:07B-007
76:078-008
76:078-010
Soil Texture
76:020-042
76:020-047
76:020-081
76:020-105
76:020-107
76:03F-076
76:05B-010
Soil Treatment
76:020-010
76:040-001
76:050-006
Soil Types
76i020-001
76:020-012
76:020-013
76:020-014
76:020-090
76i02J-001
76:02J-008
76:02J-011
76:03F-001
76:03F-076
Soil Water
76j02A-003
76:020-001
76)020-004
76:020-001
76:020-002
76:020-003
76:020-009
76:020-011
76:020-012
76:020-016
76:020-022
76:020-024
76:020-025
301
-------
Soil Water
(cont.)
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
:02G-026
:02G-028
:02G-032
:02G-034
:02G-Q49
:02G-052
:02G-055
:02G-064
:02G-067
:02G-073
:02G-074
:02G-075
:02G-078
:02G-080
:02G-083
:02G-084
:026-093
:02G-094
:02G-095
:02G-096
:02G-097
:02G-098
:02G-099
:02G-102
:02G-1Q3
:02G-108
:026-110
:02G-113
:02G-114
:02G-123
:02G-124
:02G-127
:02K-Q20
:03B-002
:03F-004,
:03F-010
:03F-016
:03F-025
:03F-033
:03F-040
:03F-044
:03F-049
:03F-055
:03F-059
:03F-065
:03F-067
:03F-069
:03F-076
:03F-079
:03F-084
:03F-095
:03F-097
:03F-098
:03F-100
:03F-110
:03F-121
:03F-139
:03F-140
:05A-010
:05A-013
:05B-023
:05B-044
:07B-012
:07B-014
:07B-016
Soil Water Movement
76:020-002
76.-02G-001
Soil Water Movement
(cont.)
76:02G-002
76:02G-005
76:020-006
76:02G-008
76:026-010
76:026-016
76:02G-019
76:026-024
76:02G-025
76:02G-026
76:026-028
76:02G-029
76:02G-032
76:02G-035
76:02G-040
76:02G-041
76:02G-049
76:02G-050
76:02G-052
76:02G-054
76:02G-067
76:02G-070
76:02G-072
76:026-073
76:02G-074
76:026-079
76:026-082
76:02G-083
76:02G-086
76:026-088
76:026-089
76:026-091
76:026-092
76:026-095
76:02G-096
76:026-102
76:026-108
76:026-110
76:026-113
76:026-114
76:026-121
76:026-122
76:02K-020
76:03F-010
76:0.3F-018
76:03F-025
76:03F-100
Soil-Water-Plant
Relationships
76:020-001
76:020-010
76:026-075
76:026-086
76:03F-025
76:Q3F-026
Soil Water Stress
76:03F-095
Soils
76;02D-005
76:02E-002
76:026-002
76;026-003
76:026-005
76:026-006
76:026-007
76:026-008
76:026-009
76:026-011
76:026-012
Soils
(cont.)
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76
76;
76:
76;
76;
76:
76
. 76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76;
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
76:
:026-013
:026-014
:026-015
:02G-016
:026-024
:026-029
:-02G-031
:02G-034
.-02G-035
:026-036
:026-038
:02G-039
:02G-040
:02G-041
:026-042
:026-046
:02G-Q47
:026-Q48
:026-051
:02G-053
:026-054
:026-057
:026-059
:026-061
:026-063
:026-065
:026-066
:026-067
:02G-068
:026-071
:026-072
:02G-078
:02G-079
:026-080
:026-081
;026-083
:026-084
:02G-085
:02G-087
;02G-091
02G-
026-
026-
02G-
02G-
026-
026-
026-
026-
026-
02G-
026-
026-
026-
02G-
02J-
02J-
02J-
02J-
02K-
02K-
02K-
02K-
02K-
02K-
02K-
02K-
02K-
•092
•093
•095
•096
•099
•102
•103
104
105
•106
•107
108
109
•111
112
•001
•002
004
•014
•002
•005
•008
010
•013
•014
•017
•018
•019
302
-------
Soils
(cont.)
76:02K-021
76:03F-004
76:03F-007
76:03F-008
76:03F-009
76:03F-030
76-.03F-084
76:03F-100
76:040-001
76:05B-003
76:058-008
76:058-012
76.-05B-014
76:05B-015
76:056-019
76:056-020
76:078-004
76:078-005
76:078-007
76:07B-015
76:076-027
Solar Radiation
76:02B-006
76:020-002
76:020-011
76:076-017
Solubility
76:02G-063
76:08G-003
Southeast U.S.
76;t)2K-012
Southwest U.S.
76:05G-001
Solutes
Sorghum
76:02F-021
76:02G-050
76:02G-084
76:02G-091
76:020-001
76:020-002
76:020-007
76:020-003
76:03F-030
76:05G-006
Sorption
76:026-003
76:02G-020
76:026-038
76:02G-094
76:02G-098
76:026-099
76:026-104
76:02K-001
76:02K-010
76:02K-013
76:05B-012
76:056-023
76:056-038
South America
76:02E-004
South Dakota
76:03F-093
76:05A-009
Soybeans
76:020-
76:020-
76:02E-
76:02G-
76:021-
76:02J-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:03F-
76:078-
•002
•008
•Oil
•062
•001
-015
•007
•052
•073
•074
•079
•097
•098
•111
•019
Spatial Distribution
76:02G-084
Specific Retention
76:02F-004
76:02F-015
Specific Yield
76:02F-005
76:02F-012
76:02F-016
Spraying
76-.03B-003
76:036-004
Spring Waters
76:02F-003
76:058-019
Springs
76-.02F-024
Sprinkler Irrigation
76:030-009
76:03F-033
76:03F-034
76:03F-038
76:03F-048
76:03F-064
76:03F-071
76:03F-078
76:03F-081
76.-03F-092
76:03F-103
76:03F-106
76:03F-107
76:03F-128
76:03F-129
76:03F-130
76:03F-132
76:03F-133
76;03F-134
76:03F-137
76:04A-007
Sprinkler Irrigation
Ccont.)
76:04A-012
76:050-005
76:056-021
76:060001
76:076-011
76:07B-025
Sprinklers
76.-03F-107
Sprinkling
76:03F-034
76:03F-038
76:04A-007
Stability
76i02F-013
Stabilization
76:040-001
Standards
76:056-012
76i05G-016
State Goverments
76:056-017
Statistical Analysis
76:02E-005
Statistical Methods
76:02E-008
76:02J*-010
76:048^006
76:05A-005
76:058-030
76:058-032
76:05G-011
Statistical Models
76:02A-004
76 04B-006
76:040-003
Statistics
76|02B-002
76:026-003
76:02E-008
76:02J-008
76j05A-005
Steady Flow
76s02F-001
76:026-073
76i026-091
Sterilant
76:026-061
Stochastic Processes
76:02A-007
76:028-004
76:028-005
76:026-010
761026-070
303
-------
Stochastic Processes
(cont.)
76:02G-088
76:03F-059
76:04B-006
Streams
Sulfates
Stomata
Storage
76:020-002
76:021-007
76:03B-004
76:03F-026
76:03F-055
76:03F-075
76:02K-020
Storage Capacity
76:020-096
Storage Coefficient
76:02F-012
76:02F-016
76:02F-029
76:048-007
76:050-009
76:07C-001
Storm Drains
76:056-015
Storm Runoff
76:02E-001
76:04A-006
76:058-040
76:05G-021
Storms
76-.02B-002
76:028-003
76:02G-018
76:02J-001
Stratification
76:02G-036
Streamflow
76:02A-003
76:020-009
76:02E-004
76:02E-005
76:02E-014
76:038-002
76:038-003
76:040-001
76:058-033
76:058-047
76:06F-001
Streamflow Forecasting
76:02A-001
76:02A-002
76:02E-005
Stream Gages
76:02A-001
76:02A-006
76:02F-014
76:05A-002
76:058-025
76:05B-029
76-.05B-033
Stress
76:02F-012
Strontium
Subsoil
76:03F-014
76:02G-079
76:02G-096
Subsurface Drainage
76;02F-032
76:02G-069
76:02G-081
76i03F-044
76;05B-004
76:05G-003
Subsurface Drains
76;02G-069
Subsurface Flow
76:02F-028
76:05B-025
Subsurface Irrigation
76:02F-032
76:02G-037
76:03F-001
76:03F-018
76-.03F-033
76:03F-050
76:03F-051
76:03F-118
76:078-013
Subsurface Runoff
76:05B-002
Subsurface Waters
76:02F-008
76302F-010
76:02F-023
76:02F-026
76:02G-085
76)058-025
Sugar Beets
76;03F-071
76:03F-083
76:03F-084
76;03F-092
76:03F-112
Sugarcane
76:03F-008
76:03F-056
76;03F-064
76:02K-002
76;05A-002
76:05D-001
Sulfur
76:03F-056
76;03F-076
76:050-001
Sulfur Bacteria
76:05A-007
Sulfur Compounds
76:020-020
Sulphuric Acids
76:03C-014
Summer
Surface
76:06A-006
76:07B-030
Surface Drainage
76:020-081
Surface-Groundwater-
Relationships
76:020-009
76:02F-014
76:058-025
Surface Irrigaiton
76:03F-043
76:03F-109
76:03F-111
76:03F-131
76:03F-133
76:03F-138
76:04A-008
76:07B~025
Surface Runoff
76:02E-002
76:02G-014
76:03C-001
76:04A-009
76:04C-001
76:040-003
76:05B-001
76:05B-009
76:05B-016
76:058-018
76:05G-007
76:07B-006
76:078-024
Surface Water
76:05A-002
76:058-040
76:06F-001
Surfactants
76;02G-054
76:02K-009
304
-------
Surveys
76:02G-009
76:02G-013
76:05B-037
Suspended Load
76:040-005
Suspended Solids
76:02J-006
76:05A-005
Systems Analysis
76:02A-005
76:02A-007
76:028-004
76:02F-017
76:03B-019
76:03F-029
76:03F-059
76:04B-001
76:04B-003
76-.04B-004
76:05B-028
76:05B-029
76:05B-030
76:05B-031
76:05B-032
76:058-042
76:05G-004
76:05G-008
76:05G-009
76:05G-010
76:05G-011
76:05G-012
76:06A-001
76:06A-002
76:06A-003
76:06A-004
76:06A-005
76:06A-006
76-.06A-007
76:060-001
76:060-002
76:088-003
Synthetic Hydrology
76:02A-004
76:04A-006
Tailwater
76:030012
76:03F-043
76:03F-138
76:058-049
Technology
76:03F-134
76:05G-012
76:05G-020
76:06A-002
Temperature
76:020-001
76:020-002
76:020-003
76:02E-008
76:023-022
Temperature
(cont.)
76:02G-040
- 76-.02G-053
76-.02G-064
76:02G-119
76:021-003
76-.03F-032
76:03F-041
76-.03F-121
76:05A-005
76:050-002
76:050-004
76:076-013
76:078-014
76:08B-004
Tennessee
76:02K-012
76-.03F-069
Tensiometers
76:02G-005
76:02G-110
76:03F-108
76:03F-047
76:03F-084
Terracing
76:03F-063
Tertiary Treatment
76:056-032
Testing
76:02F-018
76:03B-001
76:04A-001
Test Wells
76:04B-008
Testing Procedures
76:03F-027
Texas
76:02E-007
76:02E~013
76:030-016
76:030-017
76:03F-030
76:05B-018
76:050-006
76:056-007
76:056-009
Theis Equation
76:Q2F-012
76:02F-013
76-.02J-012
Theoretical Analysis
76:020-013
76:02F-007
76:02F-011
76:02F-021
76:02F~025
76:026-071
Theoretical Analysis
(cont.)
76:026-073
76:02G-090
76:026-092
76.-02G-100
76:02G-101
76:03F-018
76:04A-002
76:05B-023
Theory
76:03F-019
Thermal Conductivity
76.-02G-007
76-.02G-008
76:026-039
76:02G-040
76:050-002
Thermal Pollution
76:05B-022
76:058-027
76:05B-031
Thermal Stratification
76:05B-031
Thermodynamic Behavior
76:020-001
Thermodynamics
76:026-032
Thiems Equation
76:02F-019
Tidal Marshes
76:021-005
Tidal Waters
76:058-027
Tile Drainage
76:026-069
76:056-003
76:088-003
Tile Drains
76:02G-069
76i08B-003
Till
Time
76:03F-007
76i02F-Q07
76:02F-089
76:058-028
Time Lag
76:020-001
Time Series Analysis
76j02A-004
76i02A-006
76:028-002
305
-------
Time Series Analysis
(cont.)
76:02E-008
76:04B-006
76:05A-005
Tobacco
76:03F-080
Tomatoes
76:03F-035
76:03F-061
76:03F-062
Topography
76:02A-001
Topsoil
76:02G-002
76;02K-008
Trace Elements
76:02F-003
76:02F-024
76:05B-023
Tracers
76:02G-002
76:05B-030
76:05B-032
Translocation
76:020-048
Transmissivity
76:020-009
76:02F-010
76:02F-OJ.9
76:02F-022
76:056-009
76:070001
Transpiration
76:020-001
76:020-002
76:020-006
76:-2D-013
76:02G-086
76:021-007
76:03B-003
76:03F-040
76:03F-068
76:03F-070
TRanspiration Control
76:03B-003
76:038-004
Treatment
76:05G-012
Tributaries
76:02A-006
76:02E-004
Tritium
76:02G-050
76:05B-014
76:05B-037
Tropical Regions -
76:02G-096
76:02J-001
Urban Runoff
76:05A-002
Ureas
Tubes
76:05A-003
Turbulance
76:04B-007
76:05B-030
Turbualent Flow
76:05B-027
76:05B-031
76-.05B-033
76:02K
76:030
76:03F
76:03F
76i03F
76:03F
76:03F<
76;03F<
76:03F.
-016
-001
-006
-008
-032
-035
-053
-085
-090
Turf
Vapose Water
76:02K-020
76:05B-038
76:03F-053
76:03F-118
Value
76:02A-005
Turf Grasses
76:030-001
76:03F-053
76:03F-118
Underground Waste Disposal
76:05B-024
Uniformity
76:03F-130
76:03F-132
Uniformity Coefficient
76.-Q3F-Q38
76:Q3F-Q48
76:Q3F-Q99
76i04A-Q07
76:Q8B-007
Unsaturated Flow
76;02F-002
76:02G-002
76:02G-003
76:026-010
76:02G-011
76:02G-029
76:02G-050
76:026-070
76:026-072
76:026-073
76:026-074
76:02G-088
76:026-089
76:026-090
76:026-097
76:026-100
76,-026-101
76:026-103
Unsteady Flow
76:02F-002
76:02F-012
76:02F-020
76:02F-029
76:02G-029
76:026-072
76:026-091
76:02G-092
76:04B-007
76:05B-027
Vapor Pressure
76|03F^075
Variability
76:02B<-002
76:026-079
Vegetation
76:020-004
76;02D-Q06
76:02J-013
76:03F-016
76;04A-003
Vegetation Effects
76 1026^-013
76:02J-013
76:040-003
Velocity
76s02F-001
76)026-100
76:05B-030
76:056^-033
Venturi Flumes
76:08B-008
Viability
76:021-003
Viscosity
76:026-006
76:026-082
76:04A-002
76;04A-003
76:08B-002
76:086-004
Viscous Flow
76:026-006
Volatility
76s02K-016
Volumetric Analysis
76:08GT-003
306
-------
Washington
76:02A-001
76:02A-002
76:050-021
Vlaste Assimilative
Capacity
76:058-029
Waste Dilution
76:05B-038
Waste Disposal
76:05A-006
76:05B-024
76:05B-035
Waste Disposal Wells
76:05B-024
Waste Dumps
76:05A-006
Waste Storage
76:02K-020
Waste Treatment
76:058-035
76:056-008
Waste Water •
76:05B-034
Waste Water Disposal
76:02K-020
76;05B-038
76:050-002
76:05G-020
Waste Water Treatment
76:058-038
76:050-001
76:050-003
Wastes
Water
76:05B-024
76.-05B-025
76:05G-004
76:020-001
76:020-004
76:02D-010
76:03F-016
76:05G-027
76:060-002
Water Allocation
76:06D-002
Water Allocation (Policy)
76:06A-002
76:06A-006
76:06F-001
Water Analysis
76:02E-004
76:05A-002
76:05G-014
76:05G-021
Water Balance
76:020-010
76:02G-041
76:030-001
Water Chemistry
76:05A-002
76:05B-023
76:056-021
Water Conservation
76:026-025
76:038-003
76:038-004
76:03F-002
76:03F-003
76:03F-004
76:03F-024
76:03F-051
76:03F-122
76:03F-124
76:03F-125
76:03F-127
76:040-001
76:060-002
Water Costs
76:03r-059
76:04A-011
76:060-001
76:060-002
Water Delivery
76:060-002
Water Demand
76-.06A-002
76:060-001
76:06F-001
Water Distribution (Applied)
76:03A-001
76:03F-001
Water Flow
76:05B<-053
Water Harvesting
76:040-001
Water Law
76-.06F-001
Water Level Fluctuations
76:02F-011
76:02F-025
76:048-011
Water Levels
76:02F-011
76:02F-019
76:04A-002
76:048-006
76:048-010
Water Loss
76:02A-007
76.-02D-001
Water Management
76:05G-020
76:06C-002
76:078-013
Water Management
(Applied)
76i03C-001
76i03F-002
76:03F-024
76i06A-006
76:088-003
Water Measurement
76)020-001
Water Policy
76:03F-028
76:03F-030
76.-04A-004
76:048-003
76:056-005
76:056-016
76:060-001
76:06F-001
Water Pollution
76:02E-002
76:026-054
76;05A-004
76:05A-005
76:05A-006
76:05A<-007
76:058-001
76i05B-OQ3
76-058-004
76(058-024
76:058-029
76:058-032
76:058-037
76s05B-038
76:058-041
76:058-051
76:056-007
76:056-013
76:056-016
76:056-017
76:06A-011
Water Pollution Control
76:058-035
76:058-042
76:056-005
76:056-010
76:056-011
76*056-014
76:056-015
76:06A-001
76s06A-011
Water Pollution Effects
76:056-017
Water Pollution Sources
76:05A-002
76-.058-002
76:058-004
76i05B~013
307
-------
Water Pollution Sources
(cont.)
76:05B-024
76:05B-032
76:05B-033
76:058-035
76:05B-040
76:056-051
76:05G-005
76:05G-007
76:05G-010
76:05G-014
76:05G-016
76:05G-017
Water Pressure
76:02G-082
76:02G-089
Water Properties
76:05A-002
76:078-003
Water Quality
76:02E-001
76:02E-010
76:02E-014
76:02F-003
76:02F-006
76:02F-024
76:02F-034
76:02G-050
76:020-054
76:02G-128
76:02J-006
76:02K-012
76:030-011
76:030-012
76:030-013
76:030-016
76:03F-135
76:040-006
76:05A-002
76:05A-005
76:05A-007
76:05A-009
76:058-001
76:056-002
76:05B-Q04
76:05B-007
76:058-011
76:058-016
76:058-019
76:058-021
76:058-029
76:058-033
76:058-040
76:05B-041
76:058-042
76:05B-043
76:058-049
76:058-051
76:058-052
76:05B-056
76:050-001
76:050-002
76:050-003
76:05G-001
76:05G-002
Water Quality
(cont.)
76:056-003
76;05G-006
76:056-015
76:05G-016
76:05G-017
76:05G-019
76:05G-022
76:06A-006
76:06A-011
76:06E-001
76:07B-003
76:078-024
76:086-003
Water Quality Control
76:05A-009
76:058-028
76:058-051
76:050-001
76:050-002
76:056-009
76:05G-020
76:06A-011
Water Quality Management
76:02E-014
76:078-024
Water Quality Standards
76:05G-016
76:06A-011
Water Quantity
76:030-001
76:05G-007
76:05G-008
Water Requirements
76:03F-039
76:078-004
Water Resources
76:02A-007
76:02B-003
76;03A-001
76:03B-001
76:03E-001
76:03F-028
76:03F-030
76:04A-004
76:048-009
76:058-043
76:058-051
76:050-001
76:056-012
76;05G-015
76:056-016
76:06A-001
76:06A-002
76:06A-004
76:06A-QQ5
76:Q6A-Q07
76:06A-011
76:Q6E-QQ2
76;Q6F-Q01
VJater Resources
Development
76:048-005
76:06A-006
76:060-002
76:06F-001
Water Rights
76:03E-001
76:048-005
Water Salinity
76:05B-016
76:078-003
Water Sampling
76:05A-003
76:078-006
Watershed Management
76i02E-013
76i02J-008
76i02J<-016
76i03C-001
76j03F~063
76s04C-001
76:040-003
76:058-052
Watersheds
76:02E-01JL
76:02E-013
76i02E^014
76i02J-016
76:058-047
76i05Bv050
Watersheds (Basins)
76:02A-003
76:02A-005
76:02A-006
76:02E-001
76;02E^006
76;02E-007
76i02E^009
76:92F-028
76s02G-013
76:02J-010
76:038-002
76:038-004
76:04A-006
76:040-001
76:040-003
76:05B-002
76:058-009
76i05B-011
76:058-018
76:058-040
76:056-007
76:056-021
Water Spreading
76i02G-00'5
76:026-102
308
-------
Water Storage
76:02F-004
76:02F-015
76:02G-078
76:02G-096
76:03A-001
Water Supply
76:02C-001
76:020-013
76:03A-001
76:03E-001
76:03F-029
76:040-001
76:Q5A-Q13
76:06A-002
76:06A-003
76:06A-006
76:06C-002
76:06D-001
76:06F-001
76:08G-003
Water Supply Development
76:060-002
Water Surface
76:05A-014
Water Table
76:02F-001
76:02F-002
76:02F-005
76:02F-006
76:02F-008
76:02F-016
76:02F-019
76:02F-020
76:02F-025
76:02F-032
76:02G-028
76-.02G-093
76:026-123
76:02K-020
76:02L-001
76:Q3F-018
76:03F-026
76:04A-002
76:04B-006
76:058-024
76:05B-032
76:056-009
Water Table Aquifers
76:02F-012
76:02F-019
76:02F-025
Water Temperature
76:02E-008
76:05A-005
76:053-022
76:056-031
76:086-004
Water Treatment
76:050-003
76:05F-001
76:056-016
Water Use Efficiency
76:03F-066
Water Utilization
76:03A-001
76:03F-028
76:03F-030
76:03F-063
76:056-001
76:056-020
76:06A-006
76:060-002
76:06D-001
Water Vapor
76:026-007
76:026-008
76:02G-040
76:03F-052
76:03F-068
Water Wells
76:02F-007
76:02F-012
76:02F-016
76:02F-019
76:02F-022
76:02F-023
76:046-002
76:04B-006
76:046-007
76:046-011
76:056-032
76:056-037
76:058-039
Water Yield
76:02A-003
76:02F-022
76:038-002
76:040-001
76:040-003
76:056-014
Water Yield Improvement
76:038-003
76:038-004
76:040-001
Waves (Water)
76i05B-026
Weather
76:03F-029
76:03F-030
Weathering
76:040-001
Weather Modification
76:028^-008
Well Casings
76;02F-011
76:05A-004
Well Filters
76:02F-011
Well Screen
76:056-009
Wells
Wetting
Wheat
76i02F-003
76i02F-022
76:02F-023
76:02F-029
76i04B-001
76:04B-007
76:05A-006
76:05B-037
76:058-033
76:086-001
76:020-001
76:026-003
76:020-016
76:020-071
76:026-083
76:026-087
76:026-089
76:026-099
76:026-058
76:026-078
76:026-118
76:021-007
76:03F-002
76:03F-004
76:03F-011
76:03F-015
76:03F-027
76:03F-057
76-.03F-063
76:03F-068
76.-03F-072
76:03F-088
Wildlife
76i03F-045
Wildlife Habitat
76:03F-045
Wildlife Management
76:03F-045
Wind Velocity
76:020-003
76:03F~048
76:03F-130
76:056-022
Wind Speed
76)078-021
Winds
Well Data
76:048-006
76:020-003
76:03F-038
76:03F-048
76:03F-130
76j04A-007
309
-------
Winter
76:028-002
Wisconsin
76:026-111
76:03F-090
76:05G-005
Withdrawal
76:04B-010
76:04B-011
Wyoming
76:043-009
76:06E-002
X-Ray Diffraction
76:02G-112
76:02J-006
X-Ray Spectroscopy
76:07B-001
Xylem
76:02G-092
76:03F-025
76:03F-049
Zinc
76:02K-019
76:03F-013
76: 03F-061
76:03F-062
76:03F-081
76:03F-086
76:058-055
76:076-001
Zone of Aeration
76:058-032
310
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/2-78-042
4. TITLE AND SUBTITLE
SELECTED IRRIGATION RETURN FLOW QUALITY ABSTRACTS 1976
Sixth Annual Issue
7. AUTHOR(S)
G. V. Skogerboe, S. W. Smith, and W. R. Walker
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Agricultural and Chemical Engineering
Colorado State University
Fort Collins, Colorado 80523
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research Laboratory-Ada, OK
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
March 1978
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1BB770
11. CONTRACT/GRANT NO.
R-800426
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
16. 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 perti-
nent to the National Irrigation Return Flow 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 and
fifth annual issues cover literature published in 1974 and 1975. This annual issue
lictc mihi-iraHnnc nrintpd 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.
(Skogerboe-Colorado State)
?7. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Fertilizers, Irrigated land, salinity.
18. DISTRIBUTION STATEMENT
Release to Public
b.lDENTIFIERS/OPEN ENDED TERMS
Irrigation systems, Irri-
gation water, Nitrates,
Phosphates, Return flow,
Water pollution effects,
Water pollution sources,
Water quality control.
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COSATI Field/Group
68A
98C
21. NO. OF PAGES
319
22. PRICE
EPA Form 2220-1 (9'73)
311
4V.&
fUMIW OH** B7V-260-880/55
------- |