EPA-600/2-76-187
October 1976
Environmental Protection Technology Series
DESIGN PARAMETERS FOR THE
LAND APPLICATION OF DAIRY MANURE
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Georgia 3Q601
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161,
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EPA-600/2-76-187
October 1976
DESIGN PARAMETERS FOR THE LAND
APPLICATION OF DAIRY MANURE
by
S. D. Klausner
P.J. Zwerman
D.R. Coote
Cornell University
Ithaca, New York 14850
Project Number S800767
Project Officer
Lee A. Mulkey
Technology Development and Applications Branch
Environmental Research Laboratory
Athens, Georgia 30601
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ATHENS, GEORGIA 30601
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DISCLAIMER
This report has been reviewed by the Athens Environmental Research
Laboratory, US Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of the US Environmental Protection Agency,
nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
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ABSTRACT
The effects of climate, application rate of dairy manure, timing of
application and soil management practice were studied in relation to
discharge of nitrogen and phosphorus via surface runoff, sediment and
tile effluent.
Losses of nutrients from the land were influenced by the rate and
timing of manure application in addition to the type of climatological
event causing runoff. The greatest discharge of nutrients resulted
from applying manure on actively melting snow. Modest rates of applica-
tion made in the winter during non-snowmelt periods resulted in minimal
losses. Concentrations of nitrogen in surface runoff, as measured
over time, were lower than those found in tile effluent. The reverse
was true for soluble phosphorus. The yield response of corn increased
while efficiencies of nitrogen utilization decreased at the higher
rates of application.
A computer model dealing with the economic impact of control legisla-
tion was developed. Modeling approaches to farm scale environmental
problems are feasible if assumptions and simplifications do not in-
fluence the results too greatly, or in ways which are unpredictable.
This report was submitted in fulfillment of Grant lumber S 800767 by
Cornell University, Ithaca, New York under the partial sponsorship of
the Environmental Protection Agency. Work was completed as of
October, 1971*.
ill
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CONSENTS
Section
I Conclusions
II Recommendations
III Land Application of Dairy Manure
IV Guidelines of Land Application of Manure
V An Economic Impact and Water Quality Evaluation of
Certain Proposed Animal Waste Disposal Legislation
with Respect to Dairy Farms
VI A Comparison of Conventional and Improved Dairy
Waste Management on Two Hypothetical Dairy Farms
VII Summary
VIII References
IX Glossary
X Appendix
Page
1
5
7
122
133
198
20k
218
226
230
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FIGURES
No._ ^S
1 Annual Precipitation Divided into 5 Day Periods
at Aurora, N.Y. 1972. 15
2 Annual Precipitation Divided into 5 Day Periods at
Aurora, N.Y. 1973. '
Average of the Rainfall Factor (R).
18
it Average Annual Number of Days with Snow Cover
Exceeding 2.5 cm. "
5 Yearly Comparisons of Inorganic-N and Total
Soluble-P in Surface Runoff. 22
6 Yearly Comparisons of Total-N and Total-P in
Sediment. . . 25
•7 Nitrogen and Phosphorus Losses from a Snow Melt
Event with Respect to Loading Rate. 2/29/72. 35
8 Nitrogen and Phosphorus Losses from Hurricane Agnes
with Respect to Loading Rate and Time of Manure
Application. 6/26/72. ' 38
9 Nitrogen and Phosphorus Losses from an Intense
Rainstorm with Respect to Loading Rate and Time
of Manure Application. 8/27/72. ^0
10 Nitrogen and Phosphorus Losses from Moderate
Rainfall with Respect to Loading Rate and Time of
Manure Application. 12/7/72. ^2
11 Nitrogen and Phosphorus Losses from Winter Rainfall
with Respect to Loading Rate and Time of Manure
Application. 3/19/73. ^5
12 Nitrogen and Phosphorus Losses from Spring Rainfall
with Respect to Loading Rate and Time of Manure
Application. k/6/J3. kQ
13 Nitrogen and Phosphorus Losses from Snowmelt with
Respect to Loading Rate and Time of Manure Applica-
tion- 12/27/73. 50
vi
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Ho.
1^ Nitrogen and Phosphorus Losses from Snowmelt and
Rainfall with Respect to Loading Rate and Time of
Manure Application. 2/2k/jk. 51
15 Nitrogen and Phosphorus Losses from an Intense Rainfall
with Respect to Loading Rate and Time of Manure
Application. 6/11/71*. 53
16 Discharge of Inorganic-N in Runoff for Nine Selected
Events with Respect to Rate of Manure Application. 58
IT Discharge of Total Soluble-P in Runoff for Nine
Selected Events with Respect to Rate of Manure
Application. 59
18 Three Year Comparison of Inorganic Nitrogen and
Total Soluble Phosphorus Discharge in Surface
Runoff Due to Winter Disposal. 63
19 Three Year Comparison of Total Nitrogen and Total
Phosphorus Discharge in Sediment Due to Winter Disposal. 65
20 Distribution of Ammoniacal Nitrogen Concentrations
in Surface Runoff with Respect to the Rate of Manure
Application. 1972, 1973. 69
21 Distribution of Ammoniacal Nitrogen Concentrations
in Surface Runoff with Respect to Timing of Manure
Application. 1972, 1973. 70
22 Distribution of Nitrate Nitrogen Concentrations in
Surface Runoff with Respect to the Rate of Manure
Application. 1972, 1973. 72
23 Distribution of Nitrate Nitrogen Concentrations
in Surface Runoff with Respect to Timing of
Manure Application. 1972, 1973- 73
2k Distribution of Inorganic Phosphorus Concentrations
in Surface Runoff with Respect to Rate of Manure
Application. 1972, 1973. 77
25 Distribution of Inorganic Phosphorus Concentrations
in Surface Runoff with Respect to Timing of Manure
Application. 1972, 1973. 78
vn
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Mo.
26 Distribution of Total Soluble Phosphorus Concen-
trations in Surface Runoff with Respect to Rate
of Manure Application. 1972, 1973.
27 Distribution of Total Soluble Phosphorus Concen-
trations in Surface Runoff with Respect to Timing
of Manure Application. 1972, 1973.
28 Distribution of Ammoniacal Nitrogen Concentrations
in Tile Effluent with Respect to the Rate of Manure
Application. 1972, 1973.
29 Distribution of Ammoniacal Nitrogen Concentrations
in Tile Effluent with Respect to Timing of Manure
Application. 1972, 1973. °5
30 Distribution of Nitrate Nitrogen Concentrations in
Tile Effluent with Respect to the Rate of Manure
Application. 1972, 1973. °°
31 Distribution of Nitrate Nitrogen Concentrations
in Tile Effluent with Respect to Timing of
Manure Application. 1972, 1973- 89
32 Distribution of Inorganic Phosphorus Concentrations
in Tile Effluent with Respect to the Rate of Manure
Application. 1972, 1973. 92
33 Distribution of Total Soluble Phosphorus Concen-
trations in Tile Effluent with Respect to the
Rate of Manure Application. 1972, 1973- 93
3^ Distribution of Inorganic Phosphorus Concentrations
in Tile Effluent with Respect to Timing of Manure
Application. 1972, 1973. 9^
35 Distribution of Total Soluble Phosphorus Concen-
trations in Tile Effluent with Respect to Timing
of Manure Application. 1972, 1973. 95
36 Phosphorus Reactions in Soil Solution. 97
37 Concentration of Nitrogen and Total Soluble Phos-
phorus During a Surface Runoff Event. 101
via
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No. Page
38 Discharge of Inorganic litrogen and Total Soluble
Phosphorus in Surface Runoff. 103
39 Concentration of Nitrate-Nitrogen and Inorganic
Phosphorus in Tile Flow. October 30-31, 1973. 105
kO Concentrations of Nitrate-Nitrogen and Inorganic
Phosphorus in Tile Flow. October 31-November 1, 1973. 106
^1 Discharge of Nitrate-Nitrogen in Tile Drainage. 109
k2 Discharge of Inorganic Phosphorus in Tile Discharge. 110
^3 Estimated Evapotranspiration in the Erie-Niagara
Basin, Normal Rainfall at Lockport, N.Y., and Stream
Flow of Little Tonawanda Creek at Linden, N.Y. 126
kk Schematic Representation of the Model - Step I. lU9
ij-5 Step I, Schematic Representation of the Functional
Relationships of the Model-Nutrient Analysis. 150
U6 Step I, Schematic Representation of the Functional
Relationships of the Model-Economic Analysis. 151
U7 Schematic Representation of the Model - Step II. 153
kQ Comparison Between Predicted and Measured Runoff.
1971-72. 155
^9 Comparison Between Predicted and Actual Runoff
Inorganic Nitrogen Loss. 1971-72. 157
50 Comparison Between Predicted Sum of Seepage and
Denitrification Nitrogen Loss and Estimated Actual
Seepage Loss. 1971-72. 158
51 Soil Loss, and Sediment Total Nitrogen and Phos-
phorus Loss Comparisons. 160
52 Fertility Yield Matrix for Five Soil Capability
Levels. l6U
53 Physical Model of the Farm. 167
5^ Net Revenue - ¥. Jefferson County. 176
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No. Page
55 Net Revenue - S. W. Oneida County. "^
56 Amount of Manure "Dumped" - ¥. Jefferson County. 178
57 Amount of Manure "Dumped" - S. W. Oneida County. 17°
58 Corn Grown as Percent of Cropped Land-Both Counties. 180
59 Alfalfa Grown as Percent of Cropped Land-Both Counties. 180
60 Oats Grown as Percent of Cropped Land-Both Counties. l8l
6l Wheat Grown as Percent of Cropped Land-Both Counties. l8l
62 Grass Grown as Percent of Cropped Land-Both Counties. 183
63 Corn Silage Grown as Percent of Corn Acreage-Both
Counties. ^3
6U Runoff as Percent of Rainfall - ¥. Jefferson County. l8U
65 Runoff as Percent of Rainfall - S. ¥. Oneida County. 18*4-
66 Soil Loss - W. Jefferson County. 186
67 Soil Loss - S. W. Oneida County. 186
68 Total Potential Nitrogen Loss- W. Jefferson County. l88
69 Total Potential Nitrogen Loss - S. W. Oneida County. 188
TO Soluble Nitrogen Loss in Runoff - W. Jefferson County. 189
71 Soluble Nitrogen Loss in Runoff - S. ¥. Oneida County. 189
72 Particulate Nitrogen Loss - ¥. Jefferson County. 191
73 Particulate Nitrogen Loss - S. W. Oneida County. 191
7^ Nitrogen Loss by Percolation and Denitrification -
¥. Jefferson County. 192
75 Nitrogen Loss by Percolation and Denitrification -
S. ¥. Oneida County. 192
76 Particulate Phosphorus Loss - ¥. Jefferson County.
77 Particulate Phosphorus Loss - S. ¥. Oneida County.
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TABLES
Wo. Page
1 Treatment Schedule, January 1, 1972 - June 1, 197^. 20
2 Flow, Inorganic Nitrogen and Total Soluble Phosphorus
Discharges in Random Tile Lines. 1972, 1973. 29
3 Adjusted Flow, Inorganic Nitrogen and Total Soluble
Phosphorus Discharges in Random Tile Lines. 1972, 1973. 30
k Characteristics of Selected Runoff Events. 32
5 Relative Severity of Selected Runoff Events. 33
6 Dairy Manure Loading and Soil Management Under
Conditions of Snowmelt as a Consideration in
Nutrient Discharge. 2/29/72. 36
7 The Influence of Soil Management on Nutrient Dis-
charge During Winter Rainfall. 12/7/72. ^3
8 Influence of Soil Management on the Discharge of
Total Nitrogen and Total Phosphorus in Sediment
for Two Isolated Treatments. 3/19/73. ^
9 Correlation and Linear Regression Coefficients for
the Discharge of Inorganic Nitrogen in Surface Run-
off Resulting from Nine Selected Events. 55
10 Correlation and Linear Regression Coefficients for
the Discharge of Total Soluble Phosphorus in
Surface Runoff Resulting from Nine Selected Events. 56
11 Comparison of Several Weather Parameters for a
Three Year Period. 6l
12 Ammonium Nitrogen Concentrations in Surface Runoff
Over a Two Year Period. 1972, 1973. 67
13 Nitrate Nitrogen Concentrations in Surface Runoff
Over a Two Year Period. 1972, 1973. 71
lk Inorganic Phosphorus Concentrations in Surface Run-
off Over a Two Year Period. 1972, 1973. 75
xi
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No. Page
15 Total Soluble Phosphorus Concentrations in Surface
Runoff Over a Two Year Period. 1972, 1973- '
16 Best Point Estimate of the. Probability that a Con-
centration of Nitrogen or Phosphorus in Surface Run-
off will Exceed Y.
17 Ammonium Nitrogen Concentrations in Weekly Tile
Effluent Samples. 1972, 1973. 5
18 Nitrate Nitrogen Concentrations in Weekly Tile
Effluent Samples. 1972, 1973- °T
19 Inorganic Phosphorus Concentrations in Weekly Tile
Effluent Samples. 1972, 1973. 9°
20 Total Soluble Phosphorus Concentrations in Weekly
Tile Effluent Samples. 1972, 1973. 90
21 Best Point Estimate of the Probability that a
Concentration of Nitrogen or Phosphorus in Tile
Effluent will Exceed Y. 99
22 Nutrient Losses from Tile Flow During a Drainage
Event. 107
23 Retention Efficiency of the Soil Based on Nutrient
Inputs from Manure and Discharges in Surface Runoff and
Sediment. 112
2k Soil Analysis of the Plow Layer as Influenced by
Additions of Dairy Manure for Three Consecutive Years. lilt
25 Mass Balance of Organic Nitrogen from Dairy Manure as
a Percent of Three Successive Yearly Inputs. 116
26 Calculation of Decay Series for each 100 Kilograms
of Organic Nitrogen for a Three Year Period. Il6
27 Corn Response to Additions of Dairy Manure. 117
28 Nitrogen and Phosphorus Uptake by Corn. 119
29 Input and Availability of Organic Nitrogen for Three
Rates of Manure Application. 120
xn
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No. Page
30 Percent Recovery of Available Nitrogen by Corn for
Three Rates of Manure Application. 120
31 Suggested Rates of Dairy Manure Applications for Plow-
down or Injection (April 1 - Sept. l) as a Percent of
the Maximum Rate. 131
32 Suggested Rates of Dairy Manure Applications for Spring
and Summer Topdressing (April 1 - Sept. l) as a Percent
of the Maximum Rate. 131
33 Suggested Rates of Dairy Manure Applications During Fall
and Winter Months (Sept. 1 - April l) as a Percent of
the Maximum Rate. 132
3^ Summary of Existing and Proposed State Regulations to
Control Livestock Related Pollution. 138
35 Examples of Existing and Proposed State Regulations
to Control Livestock Related Pollution. 139
36 Summary of Potential Waste Disposal Regulations
at Two Levels. ikh
37 Restrictions Used for Controlling Manure Disposal
Activities on Two Hypothetical New York Dairy Farms. 162
38 Standard Deviation from 30-year Mean, 1969-1971,
Temperature and Precipitation of Weekly Averages for
Growing Season at Six Central Hew York Weather Stations. 171
39 Comparative Prices per Kilogram for Fertilizer
lutrients Delivered at the Farm. 199
kQ Schematic Representation of Crop Rotation for Max-
imizing Soil Structure Improvement and Dairy Manure
Recycling. 201
Xlll
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No. Page
Al Annual Discharge of Water, Inorganic Nitrogen and
Soluble Phosphorus in Surface Runoff for Individual
Plots, 1972. 230
A2 Annual Discharge of Water, Inorganic Nitrogen and
Soluble Phosphorus in Surface Eunoff for Individual
Plots, 1973. 231
A3 Annual Discharge of Inorganic Nitrogen and Total
Soluble Phosphorus in Surface Runoff for Given
Treatments. 1972, 1973- 232
Ak Annual Discharge of Soil, Total Nitrogen, Total
Phosphorus and Organic Matter in Sediment for
Individual Plots, 1972. 233
A 5 Annual Discharge of Soil, Total Nitrogen, Total
Phosphorus and Organic Matter in Sediment for
Individual Plots, 1973. 23k
A6 Annual Discharge of Soil, Total Nitrogen, Total
Phosphorus and Organic Matter in Sediment for
Given Treatments. 1972, 1973. 235
AT Dairy Manure Composition, 1972. 236
A8 Dairy Manure Composition, 1973. 237
A9 Total Nutrient Inputs from Dairy Manure, 1972. 238
A10 Total Nutrient Inputs from Dairy Manure, 1973. 239
All Average Surface Runoff and Soil Loss for Selected
Runoff Events.
A12 Average Concentration of Inorganic Nitrogen in
Surface Eunoff for Selected Runoff Events.
A13 Average Inorganic Phosphorus and Total Soluble Phos-
phorus in Surface Runoff for Selected Runoff Events.
Average Total Nitrogen and Total Phosphorus in
Sediment for Selected Runoff Events.
xiv
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ACKNOWLEDGEMENTS
This research was supported by the Environmental Protection Agency
under project number S 800T6T and by the College of Agriculture and
Life Sciences, Cornell University. The guidance of Mr. Lee Mulkey,
Environmental Protection Agency, Athens, Georgia who served as the
Project Officer and Dr. Raymond Loehr, Cornell University, who
served as overall Project Coordinator is gratefully acknowledged.
Appreciation is expressed to Dr. P. J. Zwerman, Project Director,
Cornell University.
The principal investigators associated with the project were S. D.
Klausner (land application) and D. R. Coote (computer simulation).
The advice and help of Dr. D. Bouldin, G. ¥. Hergert, and H. T.
Greweling and the support of Dr. M. J. Wright, Chairman, Department
of Agronomy are gratefully acknowledged. Technical assistance was
provided by D. F. Ellis, R. Jones, D. Decker and E. Callinan.
The patience and skill of A. Schoneman and S. Gray in typing this
report are sincerely appreciated.
xv
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SECTION I
CONCLUSIONS
1. The soil system in itself appeared to be an excellent disposal
medium for dairy manure. The retaining efficiencies df nitro-
gen and phosphorus ranged from 89 to 99% for the imposed treat-
ments for both nutrients.
2. Throughout the course of the experiment, the lovest rate of
application (35 t/ha) yielded the lesser annual discharge of
nitrogen and phosphorus in surface runoff. The highest rate
of application (200 t/ha) resulted in nearly twice the dis-
charge of nitrogen in comparison to the lowest rate during
both 1972 and 1973.
Surface runoff discharges of inorganic nitrogen and total
soluble phosphorus showed a marked difference, for all treat-
ments, between 1972 and 1973. The average increase in 1972
over 1973 was 750% and 3^-0% for nitrogen and phosphorus, respec-
tively. Annual tile effluent quantities and discharges of nitro
gen and phosphorus were not influenced by the timing or rate
of manure application, nor soil management practices. This
clearly indicated that weather conditions are the most influ-
ential variable in studying nutrient losses.
Annual total nitrogen and total phosphorus losses in soil sedi-
ment were highly variable from year to year. Increasing incre-
ments of manure rates significantly increased nitrogen and
phosphorus losses in sediment during 1972, but the relation-
ship did not hold in 1973. Average nitrogen and phosphorus
contents in sediment were approximately 63% and h3% greater,
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respectively, in 1972 as compared to 1973, mainly associated
with increased rainfall and runoff in the former year.
Accumulative nutrient losses from winter runoff during the
inclusive months from January to April was highly variable.
Actual runoff values as averaged for the three rates of
application for nitrogen were l6, 1 and 0.2 kg/ha for 1972,
1973 and 197^, respectively. Phosphorus values averaged
3-5, 0.7, and 0.01 kg/ha for the three respective years. The
35 t/ha rate applied in the winter across an array of weather
patterns did not show any significant difference between the
three years.
Sediment losses of nitrogen and phosphorus were greatest during
the winter of 1973. When dealing with sediment losses the con-
dition of the soil surface is all important. With a given
amount of precipitation, sediment yields would be greatest on
an exposed surface as compared to an unexposed surface. The
number of days of snow covered soil in 1972, 1973 and 197^ were
75, 39 and 6k, respectively. In theory, soil protection from
rainfall impact resulting from winter rains was lower in 1973,
than in 1972 or 197^ because of less snow cover.
A snow melt event in 1972 served to illustrate the necessity to
avoid spreading of manure on melting snow. The data clearly in-
dicated that manure disposal during active thaw periods can
result in excessive nutrient losses and high nutrient concen-
trations. Low rates of application (35 t/ha) disposed on
frozen soil and then covered with snow before a thaw period
resulted in acceptable nutrient losses when compared to areas
that received no manure at all.
6. Residual nitrogen and phosphorus from previous manure appli-
cations influenced nutrient discharges the following year. Resi-
dual nitrogen exhibited a greater availability for runoff than
residual phosphorus. Due to residual influences of manure,
nutrient discharges during winter runoff can be greater from
areas that received manure during the previous spring and
summer in comparison to recent winter applied manure.
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A soil structure variable (good versus poor) proved to be very
important. Well managed soils had significantly lower nitro-
gen and phosphorus discharges in runoff especially during an
abnormally wet year in comparison to poorly managed soils,
because of improved soil structure. In both 1972 and 1973,
surface runoff was twice as great on poorly managed soils.
The probability of high nitrate nitrogen concentrations (10+
ppm) in surface runoff was extremely small (range l-lh% of the
time for the various treatments). However, the probability of
high total soluble phosphorus concentration (0.1 + ppm) was
great (range 37-8l% of the time for the various treatments).
Hitrate nitrogen concentrations in tile effluent exceeding
10+ ppm ranged from lQ-82% of the time for the various treat-
ments. However, the probability of total soluble phosphorus
concentrations exceeding 0.1+ ppm ranged from 1-32$ of the
time.
9- Increasing rates of manure application increased the concen-
tration of total nitrogen, available phosphorus and organic
matter in the soil as a result of the three successive annual
applications.
10. Corn responded significantly to increasing rates of manure appli-
cation. However, the efficiency of utilization of nitrogen by
the corn crop dropped markedly as the rate of application in-
creased.
11. Hypothetical legislative controls simulated on a computer
exerted their greatest influence over the dairy farms by way
of reducing the acreage of land which is available for manure
disposal. When this is coupled with low manure spreading
rates, the controls simply prevent a herd size which is repre-
sentative of today's dairy industry being reached without vio-
lating the restrictions.
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12. Increasing cow/land ratios, resulting from legislation which
requires that manure only be applied and utilized in a crop
production program, increased the loss of nutrients to sur-
face and ground water from farms with poor soils in two ways:
(a) by increasing the proportion of land cultivated for feed
requirements; (b) by increasing the rate of manure to be dis-
posed of. On farms with productive soils, land which can^be
profitably cultivated will be cropped regardless of^the size
of the dairy herd, and most manure can be utilized in crop
production. Thus cow/land ratios have little effect on losses
from these farms unless large herd sizes are involved.
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SECTION II
RECOMMENDATIONS
1. The soil should be utilized as a disposal medium for dairy manure.
In order to minimize the potential for nutrient losses to the
environment, the nutrient inputs from manure should match crop
requirements for these nutrients. Soil limitations should also
be considered.
2. Due to the wide range in climatic conditions within a year and
between years and the ability of the soil-crop combination to
minimize transport and utilize the nutrients in manure, the sug-
gested maximum rate of application for non-winter disposal is
67 metric tons/ha (30 tons/acre).
3. Manure should not be spread on actively melting snow.
Winter disposal activities should incorporate the disposal of
manure on fields that are well managed (vegetative cover, well
drained, etc.). Accumulated manure from storages should be
spread in November or early December before the beginning of
continuous snow cover. For daily spreading programs manure
should be temporarily stored during periods of active snow melt.
The suggested rate of application during the winter should
approximate 35 metric tons/ha (15 ton/acre).
k. The transport of nitrogen and phosphorus from a disposal field
can be minimized by practicing good soil management. This
includes maintaining vegetative cover and returning plant resi-
dues on the disposal field.
5- Modeling approaches to farm-scale pollution problems may be fea-
sible. However, assumptions and simplifications, while often
necessary for conceptual and computational reasons, must not
influence the results too greatly, or in ways which are unpre-
dictable .
-------
Modeling approaches dealing with the economics and response of
manure applications should not be so general that they fail to
take individual farm differences into account with particular
reference to soil characteristics. This is especially true
when guidelines or legislation are formulated for environmental
protection.
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SECTION III
LAID APPLICATION OF DAIRY MANURE
INTRODUCTION
Statement of the Problem
In the Northeastern and North Central U.S.A. there are about seven
million milk cows or approximately one cow for each 13 acres of
cultivated land. The annual manure production by these cows con-
tains approximately 500,000 tons of nitrogen and 75,000 tons of
phosphorus. This manure can be viewed as a valuable fertilizer
and also as a major source of water pollution. Agriculture must
learn how to maximize the former and minimize the latter aspect.
Changes in agricultural practices have led to the farmer now being
in a poorer position to deny 'unnatural' contribution of pollutants
such as plant nutrients and other waste materials to surface and
subsurface waters.
In many milksheds the sanitary code requires daily removal of
manure from the dairy. As a matter of convenience, many dairymen
spread manure daily on cropland, thus serving the dual function of
disposing of the manure and utilizing the nutrients for crop pro-
duction. The urgent need for manure utilization to lower the cost
of fertilization of farm crops has led to a very great interest in
land application of dairy manure. If one assumes that the value of
farm manure is proportional to the fertilizer nutrient content, the
value of manure to the farmer will increase with increasing fertilizer
costs. This should make for more care in management and handling of
manure on the part of farmers. Agricultural scientists should become
more concerned about working out effective systems of utilization.
Hopefully, the general public should look at both of these efforts with
tolerance and favor.
Land application has been the traditional method for the recycling
of animal wastes. Proper crop and land management practices should
insure that land disposal of animal wastes will remain an environmen-
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tally acceptable disposal method. Poorly planned land disposal may
result in subsequent runoff and subsurface percolation of nutrients.
Because many of the organic and nutrient constituents of these animal
wastes can be incorporated into the soil and utilized by crops, prior
waste treatment may not be necessary. Effectiveness of land removal
of pollutants from animal wastes is frequently dependent upon the
type of cropping systems and the specific manure and land management
practices.
Surface and subsurface drainage of precipitation is the basic transport
mechanism for moving nutrients from a manured cropland area to surround-
ing areas. Hence the nutrient losses from manure spread on the land are
intimately related to climatic events. There is no "average" year
or event; climatic events occur in many different sizes and temporal
distributions. In reality, regardless of how manure is handled there
is always a finite probability of some loss. However, the probability
of occurrence of a preset loss varies greatly among seasons and sys-
tems. In addition, the quantity lost will depend upon rates of addi-
tion per unit area and upon soil conditions such as infiltration rates
and percolating rates through the profile.
Engineers customarily take into account many design parameters when
planning water control structures with particular emphasis on the
frequency of excessive storm events. Engineering practice tends to
concentrate on "point sources" or a "point of design." The water
outlet of a small drainage basin is such a point. Control of water
quality and quantity at this point of design, unfortunately depends
not entirely upon engineering practice, but also upon agricultural
practice as well. This agricultural practice is widely regarded, by
non-agriculturalists, as a major source of water pollution. The term
"non-point pollution" or "diffuse sources" is generally used to char-
acterize pollutants originating from agricultural sources.
On a microscale—individual field and Individual farm scale— the
"non-point" sources are seldom ever non-point or diffuse. Agricul-
tural and land management practices tend to dictate the source of and
degree of water pollution from agriculture. For example, the prac-
tice of winter spreading of dairy manure originated from the sani-
tary code requirement of daily removal of manure from the barn.
The successful design of a land disposal operation for dairy manure
demands an evaluation of all disposal parameters. Ideally we would
like to derive what might be called "design parameters." By design
parameters we mean adjusting ones disposal activities to account for
the variability in the landscape such as soil differences and changes
in topography as well as seasonal climatological changes.
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Scope of the Work
Little information exists on the rates and methods for disposal of
untreated and treated animal wastes on the land. Of prime interest
would be the runoff and percolation associated with such disposal, the
fate of the soluble nutrients, and the quantities of wastes that can
be safely disposed of under different management systems.
This portion of the presentation will be concerned with dairy wastes
and the concept will be demonstrated at the field plot level. The
ultimate objective is to return dairy manure to the land with a min-
imum of expense and damage to water quality.
In order to demonstrate the effect of dairy manure disposal on water
quality, surface runoff and deep seepage losses of nitrogen and phos-
phorus were measured in the field from plots that have received three
different rates of free-stall dairy cow manure (35, 100, and 200
metric tons/ha) applied at three different times of the year (winter,
spring, summer) on two different systems of soil management (good vs
poor).
Well managed soils consist of plowing back plant residues after har-
vest. Poorly managed soils are those in which the plant residues
have been removed at harvest time.
Nutrient loss comparisons are from all events producing runoff, as
derived from natural rainfall from 1972-1971)-.
A preliminary set of guidelines for land disposal of manure has been
developed and is based on the best available knowledge at this time.
In addition, a computer simulation model was developed for the par-
ticular purpose of examining the effect of some hypothetical legis-
lative controls designed to reduce pollution related to dairy manure
disposal.
LITERATURE REVIEW
The nitrogen content of dairy manure will depend on the care and
management of the animals as well as the method of handling the manure
prior to spreading. The typical dairy cow will produce approximately
115 gW/day in the urine and 100 gN/day in the feces (27). This is
approximately equivalent to 5 kg of nitrogen per metric ton (10
Ibs/ton) of fresh mixed urine and feces. Weeks (7M» estimated the
phosphorus content of dairy manure to be equivalent to approximately
0.85 kg in the feces and 0.05 kg in the urine per metric ton of fresh
manure (1.8 Ibs/ton).
-------
Beyond certain limits nitrate, nitrite and ammonium nitrogen in water
to be used for human or animal consumption are considered a health
hazard. The current recommended maximum concentrations for drinking
water are 10 mg/£ as the sum of nitrite and nitrate nitrogen and
0.5 mg/£ as ammonicial nitrogen (l8). No criteria from the above
source is established for phosphorus. Because oxidized inorganic
nitrogen is readily soluble and mobile within the soil, concentrations
far exceeding these nitrogen levels may be found in percolating water
and surface waters from land receiving applications of manure (49).
Witzel et_ al_ (78) have estimated that manure applications which are
such that more than 15 kg/ha/yr (13.5 Ibs/acre) of nitrogen pass
beyond the root zone are sufficient to result in toxic levels of
nitrates in ground water under some conditions.
It is usually assumed that phosphorus is immobilized in the surface
layers of the soil and is not leached from the soil in significant
quantities (73) and can be regarded as only a trace (13). However,
Goodrich and Monke (25) point out that the ability of a soil to fix
phosphorus is far from infinite and warn of the risk of ground water
pollution with phosphorus from the incorrect design of soil waste
disposal systems. Soluble organic phosphorus from manure sources
carried in surface runoff may be somewhat resistant to adsorption on
sediment particles. Taylor and Kuniski (70) observed that soluble
phosphorus of manure origin was more persistent in runoff water than
phosphorus from inorganic sources. It is unlikely, however, that
phosphorus contamination would be a problem under application rates
which are selected to avoid nitrogen contamination. Treated manures
and effluents which may be low in nitrogen content may not satisfy
this assumption. It would appear to be reasonable to restrict the
application rate of manure to the soil based on the amount of
nitrogen which is being applied if at the same time there is a simul-
taneous restriction preventing the amount of nitrogen being increased
by fertilizer applications.
It is extremely difficult to say with any degree of certainty that
any particular application rate of manure nitrogen should not be ex-
ceeded. Much depends on the time of application, the type of crop
being grown and the type of manure. Harriot and Bartlett (U9) applied
0, 785, 1570, 2355, 31^0 and 3925 kg/ha (0, 700, lUoo, 2100, 2800, and
3500 Ibs/acre) of manure nitrogen to a crop of orchardgrass, and con-
cluded that the first increment of 785 kg/ha of manure nitrogen was
excessive and represented a pollution potential. Further study was
necessary to find what the level between 0 and 785 kg/ha was accep-
table. Weeks et al (7*0 showed that manure applications up to ^30
metric tons/ha~Tl92 tons/acre) resulted in leaching of nitrate down
through the soil profile. At all application rates, the concentra-
tion of IOo-N below the surface of the soil was considerably in
excess of 10 mg/£, but crop uptake appeared to control the level
10
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of leaching loss for application rates up to 9^ metric tons/ha (U2
tons/acre). They concluded that it was not economic to apply manure
at rates greater than 1*5 metric tons/ha (20 tons/acre).
The timing of manure inputs to the soil has become a very important
consideration, due to the objection of manure applications during
the winter months. Loehr et_ al_, (1*6) have discussed the timing of
manure applications as it relates to precipitation, evapotranspira-
tion and stream flow in the northeast. The main theme, from a pollu-
tion control standpoint, centers around the application of manure at
a time when stream flow decreases and evapotranspiration begins to
maximize.
Bryant and Slater (12) showed that, without manure, high losses of
nitrogen may be expected in runoff during winter runoff. The high
runoff losses during the winter appear to come primarily from the
leaching of organic material on the soil surface. It would appear,
then, that losses of nitrogen might be expected from winter spread
manure, but not necessarily losses of manure solids. Similar results
have been attributed to the spreading of manure on frozen soils (32,
55 5 56). The situation is difficult to evaluate in the Northeast
and North Central States because of the wide variation from year to
year in frozen soil conditions. There is also a wide variation
throughout this area in anyone particular year.
The studies of climatological processes and events reported here
aPPly "to the Northeastern and North Central U.S.A. Characteris-
tically this area has one inch or more of snow on the ground for 100
to lUO days each winter (l). Garstka has exhaustingly reviewed the
literature on snow melt and runoff (23). Without going into his
presentation, it can be said that the presence of snow in these
areas of the Northeast and North Central U.S.A. is very much a matter
of chance. Lake positions and air mass movements are major consid-
erations. Once snow has fallen, the soil beneath the snow may
previously have been subject to "concrete freezing" or "honeycomb
freezing." In the former case, water infiltration from melting
snow may be difficult or impossible. In the latter case, infiltra-
tion may be good (68). Nutrients can be carried from the soil sur-
face by melting snow, but they can also be carried by runoff from
rainfall. Predicting equations for rainfall-erosion losses from
cropland east of the Rocky Mountains are available (77). These
equations were developed for relatively small areas, but in prin-
ciple also apply to larger areas. Thus in terms of climatological
events, snow melt and rainfall are of major consideration in moving
nutrients from soil surface to water.
11
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METHODS AND MATERIALS
Site Description and Sample Collection
The experimental installation was designed to measure the quantity
and composition of surface and subsurface water flow. The experi-
mental field is comprised of approximately 12 hectares of a Lima-
Kendaia soil association at the Cornell Agronomy Research Farm near
Aurora, New York. These soils are moderately to somewhat poorly
drained and have a medium soil texture formed in strongly calcar-
eous glacial till. They have 0.3-0.5 meter of moderately per-
meable silt loam over 0.3-0.8 meter of fine silt loam that is under-
lain by firm, dense, slowly permeable glacial till.
The design includes 2k plots, each 0.32 ha (6l by 53.5 meters) in
size which were constructed in 1956. The study was maintained as
a drainage experiment until 1969. From 1969-1972, these plots were
used to evaluate water quality from farming systems using varying rates
of mineral fertilizers. In the winter of 1972 free-stall dairy cow
manure was substituted for mineral fertilizer.
Surface water was controlled by a series of small interceptor cross
ditches and broad shallow runoff ditches up and down slope. Indivi-
dual plots have surface slopes ranging from 2 to k percent. Runoff
water was diverted into a 30.5 cm H-flume, located at each plot,
where the flow volumes were measured. As water passed out of the
flume, a subsample of approximately 1% was collected by an electri-
cally driven Coshocton wheel. The sample was further divided by a
splitter arrangement which could collect either 10 or 20$ of the
subsample. The integrated water sample taken over the entire period
of flow was collected in an underground storage tank. After each
runoff event a 250 ml subsample of the collected suspension was
taken for analysis. The remaining suspension was pumped into an
above ground drum and the sediment was flocculated with CaCl?.
After settling the supernatant was poured off and the sediment was
retained for analysis. Each installation was insulated and con-
tained a heating lamp to avoid freezing during the winter.
Subsurface flow of water was studied with the use of a single
drain tile approximately one meter below the surface. These, tile
lines were centered in 12 randomly selected plots. The tile is 10
cm in diameter and empties into an underground metering tank. The
effluent empties directly into a buffer chamber before flowing through
a 90° sharp crested V-notch weir. A representative subsample of tile
flow is collected from a uniform drip flow tube into a container.
Accumulated tile effluent samples were collected on a weekly basis.
12
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Management Practice and Disposal Techniques
The manure treatments for continuous corn were selected to approx-
imate or to cover the range of practices utilized by dairy farmers
in the northeastern and north central United States. Rates (35, 100
and 200 t/ha) were selected to approximate l6o, 500, and 900 kg/ha
of nitrogen (w). The l60 kg/ha rate closely correlates to the
recommended needs of nitrogen for corn, while the 900 kg/ha rate
characterizes the extreme.
Three different times of the year for disposal were selected on the
basis of climatic conditions and restrictions associated with corn
production. There has been much discussion in the past about:
a) Spreading manure on snow or frozen soil;
b) manure should be immediately plowed down; and
c) there are not suitable places to spread manure during the
summer.
The winter, spring plow-down and summer topdress (applying manure on
top of growing corn 0-5 cm high) applications were incorporated into
the design to help answer these important questions.
Two systems of soil management were included. One involves the re-
moval of all plant residues at harvest and is denoted as poor manage-
ment. The other involves the reincorporation of plant material with
the soil (good management). Corn harvested for silage is classified
as a poorly managed soil since all of the plant residue is removed
at harvest. Corn harvested for grain enables the reincorporation of
the entire plant (except the grain) when the soil is plowed. The
addition or subtraction of organic residues to the same plots has
persisted for the last l6 years.
The design represents 18 different treatments (3x3x2). Three
rates (35, 100, and 200 t/ha) combined factorially with three dif-
ferent times of disposal (winter, spring and summer) on good and poor
managed soil. The 35 t/ha rate was replicated twice to give a total
of 2k plots. Due to the limited number of plots being underdrained
by a tile line, the 100 t/ha rate was not represented on tiled plots.
The limited number of tiled plots were used to study nutrient con-
centration at the minimum and maximum rate of application.
Manure was supplied by a local dairy farmer who operated a 175 cow
free-stall dairy operation. Each load of manure was weighed and
application rates were within 0.5 metric ton. Manure applications
were made with conventional manure handling equipment.
13
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Chemical Analysis
Surface and subsurface water samples were centrifuged at 37,000
R.C.F. (relative centrifical force) for 30 minutes. The super-
natant was analyzed for NHj-N which involved the reaction of
ammonium, phenol and hypochlorite in an alkaline medium (6l). H03~N
was determined by reducing nitrate to nitrite by copper and hydra-
zine sulfate in an alkaline solution (35). Soluble inorganic P was
determined according to a modification of Fiske and Subbarow (19) pro-
cedure. Total soluble PO.-P is analyzed by hydrolyzing polyphosphates
and oxidizing organic phosphate by heating with potassium persulfate.
The resulting ortho-phosphate is determined on an autoanalyzer (53).
Sediment samples were analyzed 'for total nitrogen, total phosphorus
and organic matter. For total nitrogen (Kjeldahl), the soil is di-
gested with sulfuric acid, potassium sulfate and copper sulfate to
convert organic nitrogen to ammonia. The ammonia is then titrated
with standard sulfuric acid in a boric acid solution (ll). Total
phosphorus is determined by ashing the soil with magnesium nitrate.
The residue is heated with hydrochloric and nitric acid to hydrolyze
polyphosphates to orthophosphate. Orthophosphate in the resulting
solution is determined by reacting with molybdic and vanadic acids
(53). Organic matter is determined by leaching the soil with a sol-
ution of potassium dichromate. Upon addition of sulfuric acid, the
heat of reaction is used to oxidize soil organic matter. Excess
dichromate is measured by titration with ferrous sulfate (26).
Manure samples were taken from each spreader load of manure.
Representative samples for analysis were composite samples of
three spreader loads. Dry matter content was determined on one
subsample. A second subsample was homogenized with an equal weight
of water in a blender for 1 minute. Subsamples of this homogenate
were analyzed for ammoniacal nitrogen, total nitrogen, soluble in-
organic P, total soluble P and total P. Ammonia was determined by
distillation with magnesium oxide (ll). Total nitrogen, and the vari-
ous forms of phosphorus were determined by the previously mentioned
procedures.
RESULTS AID DISCUSSION
The 1972 calendar year was extremely wet in the Northeastern U.S.
and a tropical storm on June 21-25 caused heavy rainfall and flood
damage. Figure 1 illustrates the distribution of precipitation
throughout the year at the Aurora experimental farm where this study
was conducted. There are three significant climatological events:
l) A thaw period in early March; 2) hurricane Agnes in June which
delivered over 17 cm of rainfall, a 1 in 100 year storm frequency;
14
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Ol
18
16
e 14
o
I12
l-
< 10
5 8
UJ
cr
4
2
0
1972 TOTAL=132cm
- MEAN (!4YR) = 79cm
It
ILilll,
JFMAM JJASOND
1972
Figure 1. Annual precipitation divided into 5 day periods at Aurora, W.Y.
1972.
-------
and 3) an intense storm in August which delivered 6.5 cm of rain in
approximately one hour, a 1 in 50 year storm frequency. There was
132 cm of rainfall in 1972, a 67% increase in comparison to the
'normal.' The 'normal' is based on a lit year mean (79 cm) from
1952-1966.
With a significant increase in precipitation, it could be assumed
that removal of nutrients by water would increase accordingly. Con-
sequently, the losses of nutrients from the land in 1972 may be
higher than that which would normally be expected.
Annual precipitation during 1973 was only 2 cm above the ik year
mean (Figure 2). Nutrient losses from the application of dairy manure
during 1973 may be more nearly typical of what can be expected than
losses incurred during 1972. The two major peaks in Figure 2 were
derived from winter rainfall in late March and the first week of April.
The Aurora experimental farm is located in central New York and has a
climatological pattern similar to many of the northeastern and central
states. Figures 3 and k are illustrations comparing two important
weather parameters among states. More specifically, Figure 3 denotes
distribution of the rainfall factor R in ¥ischmeier and Smiths (77)
universal soil loss equation. The R factor is a function of the kin-
etic energy and intensity of rainfall and is a measure of the relative
erosiveness of a rainfall event. The values given in Figure 3 are the
annual sums of the individual R values. The average of 100 for New
York is fairly typical of the northeastern and north central regions.
The number of days during a year in which the landscape is covered
with 2.5 cm or more of snow (Figure U) in central New York is also
typical of the same geographic regions as discussed for the previous
example.
From these illustrations, it is conceivable that the data presented
for central New York may be typical of the array of nutrient losses
that can be expected from a much broader geographical area.
Nutrient Discharges
The manure treatment schedule for the past three years is presented
in Table 1 and should serve as a guide throughout the text. In
general, manure applications for a particular disposal period (winter,
spring or summer) was made within a time span of k-6 days. In 1972
the winter and spring applications were made over a longer period
of time because of the interruption of adverse weather. The clima-
tological sequences during the winter application in 1972 posed a
real problem in terms of spreading but created some interesting data.
16
-------
o
16
14
12
IC-
r°
E 8
o
LJ
QC
Q.
1973 TOTAL= 81 cm
MEAN (14 YR)= 79cm
-
I. I ell III l...I I
LJ
LkllJ
LliJiJiLll
JFMAMJJASOND
1973
Figure 2. Annual precipitation divided into 5 day periods at Aurora, N.Y. 19T3-
-------
75
'EXPERIMENTAL FARM
AURORA, NEW YORK
TS.'
100
200
Figure 3. Average of the rainfall factor (R). Taken from Wischmeier (77)-
-------
• EXPERIMENTAL FARM, AURORA, N.Y.
120
100
40
Figure U. Average annual number of days with snow cover exceeding 2.5 cm (l).
-------
Table 1. TREATMENT SCHEDULE, JANUARY 1, 1972 - JUNE 1, 197^
Time of
application
Winter
Spring
Rate of applic,
metric tons /ha
35, 200
100
35, 200
100
Misc Date
Feb. 15-18, 1972
Feb. 29, 19T2
April 27-May 2, 1972
May 15, 1972
Summer
Winter
Spring
Summer
Winter
Spring
35, 100, 200
35, 100, 200
35, 100, 200
35, 100, 200
35, 100, 200
35, 100, 200
Ploved
Corn Planted
Corn Harvested
Plowed
Corn Planted
Corn Harvested
Plowed
Corn Planted
Summer
35, 100, 200
May 20-26, 1972
May 30, 1972
June 6-11*, 1972
Oct. 1972
Jan. 12-17, 1973
April 19-21, 1973
April 23-26, 1973
May 2k, 1973
June 6-21, 1973
Oct. 1973
Jan. 8-10,
April 23-26,
April 26-30, 197**
May 16, 197^
May 27-June 2, 197!*
20
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Timing and rate of application as well as soil management are im-
portant variables to consider in nutrient runoff studies. The 35 t/ha
rate was truely replicated at all treatment levels to obtain an estimate
of experimental error. The remaining plots receiving either 100 or 200
t/ha as an annual rate, applied either in the winter, spring, or summer
on either a good or poorly managed soil, were not replicated.
The section dealing with methods and materials notes that since only
one-half of the total number of experimental plots (12 out of 2k)
contain a drain tile, the 100 t/ha rate was not represented on these
plots. Tiled plots were reserved to study nutrient concentrations
at the minimum (for one replicate) and the maximum rates of applica-
tion (2 rates x 3 disposal times x 2 soil mg't practices x 1 repli-
cate = 12 individual treatments). Consequently, quantitative nutrient
losses in runoff and sediment for the intermediate rate of application
(100 t/ha) over all levels of timing and soil management may be
biased upwards due to the lack of underdrainage.
Annual Nutrient Losses -
There is some question as to the value of comparing annual losses
between various treatments because there are usually only a few storm
events during a hydrologic year which may account for a large percent-
age of an annual loss, and perhaps individual storm losses are more
meaningful. However, the authors feel that annual nutrient losses
are extremely meaningful from two standpoints. These are; (a) to
study the behavior of a particular dairy manure treatment over time
as it is influenced by a series of seasonal changes, hence, cumulative
climatological sequences and (b) in some years, climatologies! sequences
may be such that individual storm losses appear minor, but the cumu-
lative losses throughout the year may be significantly high.
Surface runoff - The annual losses of inorganic nitrogen (NH>-N +
K02~N + N03~N) and total soluble phosphorus inorganic + organic)
in runoff are presented in graphic form in Figure 5- There is a
marked difference in I and P losses between 1972 and 1973 with the
latter year being much less. Individual plot losses and tests of
statistical significance are presented in Tables Al, A2 and A3 of
the Appendix. This illustration served to support the contention that
nutrient losses from the land surface for a given treatment is highly
variable from year to year. The most influential variable, of course,
is the weather. Reference to Figures 1 and 2 indicate that during
1972 considerably more rainfall occurred while a more 'normal'
amount of rainfall occurred in 1973-
With reference to both nitrogen and phosphorus in Figure 5, the
greatest losses during 1972 occurred at the 100 t/ha rate and during
the winter application. By referring to Table Al of the Appendix,
21
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35 100 200
RATE, t/ha
W SP SU
TIME
GOOD POOR
MGT
35 100 200
RATE, t/ha
W
SP
TIME
GOOD POOR
MG'T
Figure 5. Yearly comparisons of inorganic-N and total
soluble-P in surface runoff. W, SP and SU
denote winter, spring and summer applications.
22
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it is obvious that nutrient losses at the 100 t/ha rate spread during
the winter for both good and poor soil management was responsible for
these peaks. Unlike the winter application of the 35 and 200 t/ha
treatments, the 100 t/ha rate was delayed, due to adverse weather,
and spread on dense melting snow. This surface soil condition resul-
ted in unfavorable nutrient losses, especially on a poorly managed
soil. A more thorough explanation of this phenomena is presented in
the section dealing with selected runoff events.
There are many other independent variables that are important when
considering nutrient losses from the land surface. Soil management
is one of the more important variables . Soil management played an
important role during the unusually wet year of 1972 . Good soil prac-
tice (plowing back plant residues) resulted in a lower discharge of
nitrogen and phosphorus as compared to a poorly managed soil (removal
of plant residues after harvest). Surface runoff during 1972 was
approximately 100% less on plots that were well managed in contrast
to poorly managed treatments (Table A3 Appendix) . The reduced run-
off and consequent lower nutrient discharge can be attributed to an
improved soil structure, hence greater water permeability, associated
with the well managed soils. Using aggregate stability (the percentage
of water stable aggregates) as a relative index of soil structure,
well managed plots were approximately 30% higher than poorly managed
ones (59$ versus
The addition or removal of plant organic matter, as it influences soil
structure, may become erased in future years by the larger additions
of organic matter from manure. Even if this phenomenon is masked by
future manure additions , the physical presence of a plant residue
cover on the soil surface after harvest on well managed soils would
aid in the reduction of surface runoff.
Surface water nitrogen losses during 1973 (Figure 5) were slightly
higher for the 100 t/ha rate regardless of the time of application
while losses associated with the time of application and soil manage-
ment practices were essentially identical. Phosphorus losses during
this year were significantly higher for the two highest rates as well
as for the winter application. Well managed soils reduced phosphorus
outputs by 130% as compared to poor soil management .
Whether it be nitrogen or phosphorus losses that are of concern, it
is evident that the lower rate of application (35 t/ha), regardless
of the time of application studied, results in lower nutrient loadings
With respect to time of application, manure applied in the spring,
regardless of the rates studied, and plowed down shortly afterwards,
also results in the lowest nutrient loading.
23
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Soil sediment - Direct organic matter losses from the field receiving
manure are calculated in the sediment loss. Table A6 of the Appendix
gives the organic matter losses and shows that for the average of
the two years, organic matter losses were 6k, 196, and 208 kg/ha
for the 35, 100 and 200 t/ha manure rates respectively. Consequently,
total N and total P in sediment is influenced by the nitrogen and
phosphorus associated with the sediment plus that portion associated
with the organic matter. The percentage of the sediment that was
organic matter as averaged over two years ranged from 7 to ih percent
for the values plotted in Figure 6.
The loss of total N and total P in soil sediment from the experi-
mental plots was higher in 1972 than 1973 (Figure 6) because of the
greater amount of surface runoff associated with the 1972 calendar
year. Individual plot losses and test of treatment significance for
sediment are presented in Tables A^, A5 and A6 of the Appendix.
There was a significant increase in sediment nitrogen and phosphorus
as the rate of application was increased during 1972. For 1973,
however, there was a significant increase in nitrogen losses for the
100 t/ha rate in comparison to the 35 and 200 t/ha rates. The
increases in nitrogen and phosphorus were directly associated with
the increased rate of organic matter loss (Table A6, Appendix).
The affect of timing of manure application and sediment losses for
both nitrogen and phosphorus behave similarly within each year. The
only real treatment difference that occurred in 1972 was that the
summer application resulted in lower discharges of nitrogen and phos-
phorus than the spring application but was not significantly less in
comparison to the winter application. During 1973, timing of manure
application had no real effect on nitrogen and phosphorus loadings
resulting from sediment movement.
In many cases, soil sediment and associated nitrogen and phosphorus
losses may not be a function of rate or timing of manure application
but rather a function of the soil and its topography. The greatest
losses of particulate, nitrogen and phosphorus occurred from a poorly
managed plot receiving 200 t/ha applied in the spring (Tables A^t and
A5 Appendix), in both 1972 and 1973. These losses are not character-
istic of the treatment but rather a function of the soil character-
istic. This poorly managed plot contains a complex slope (surface
topography) which runs in two directions and is more strongly sloping
than any other plot in the experiment. Since runoff and erosion is
partly a function of slope, one would expect an increase in nutrient
losses with an increase in slope gradient. This treatment showed the
highest loss for the month of June during 1972, which was due solely
to hurricane Agnes. This single runoff event on the poorly managed
24
-------
RATE, t/ha
SP
TIME
GOOD POOR
MG'T
O>
-------
plot accounted for &h% of the total soil loss and 83, TO and 15% of
the total N, total P and organic matter losses respectively. A more
detailed analysis of the above is presented in the section dealing
with selected runoff events.
The effect of soil management practice behaved similarly for sediment
losses of nitrogen and phosphorus (Figure 6) as it did for surface
water nutrient losses (Figure 5). As discussed previously, a well
managed soil (one with improved soil structure) promotes greater in-
filtration and percolation through the soil, hence a smaller percen-
tage of the rainfall appears as surface runoff. Reduced surface
runoff causes an understandable reduction in sediment movement and
reduced nutrient loadings. Notice that there is a much greater dif-
ference between good and poor soil management during a wet year (1972)
in contrast to a more 'normal' year (1973).
Extreme care should be used when interpreting the nutrient loading
from surface water and sediment. The losses of nitrogen and phos-
phorus presented are considered to be an overestimate of what would
naturally occur in a watershed. Firstly, dairy manure was spread from
adjacent to, to a maximum of 60 meters from the interceptor ditch
which diverts overland flow to the sampling device. In actual prac-
tice, this would be synonymous with spreading manure adjacent to a
stream bank. This type of disposal is not commonly practiced if not
for common sense, then because of stream location with reference to
cultivated land. Secondly, the behavior of nitrogen and phosphorus
in transport from a disposal field to a water course is not well
defined. Nutrient loadings to a water course would depend on length
of travel, additional diluting water, topography, soils, vegetation,
etc. Thirdly, loading rates of manure approaching 100 to 200 metric
tons/ha over extensive areas of a given watershed is not a common
occurrence. The data presented, however, becomes extremely im-
portant when studying the behavior of nitrogen and phosphorus losses
from a well defined disposal field.
Tile effluent - The section dealing with methods and materials points
out that due to the limited number of instrumented tiled plots, one-
half of the 35 t/ha treatment (or 1 replication) and all of the 200
t/ha treatments were tiled. It was felt, with a limited number of
internally drained plots, the minimum and maximum rates of applica-
tion should have priority.
Tiled plots consisted of a single 10 cm drain tile running the full
length of the plot (60 m), located at the center at an approximate
depth of 1 meter. The field design consisted of two rates of appli-
cation (35 and 200 t/ha), each at one of three disposal periods
(winter, spring and summer) on either a well managed or poorly
managed soil for a total of 12 treatments (2x3x2).
26
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The quantity or concentration of nitrogen and phosphorus in tile
discharge is not a reliable indicator of that which will eventually
find its way to the ground water reservoir. Artificial internal
drainage alters the natural pathways of water and consequently,
nitrogen and phosphorus movement. Surface infiltration of water
into the soil in this experiment is rapid (approximately 5 cm/hr).
The dense subsoil and underlying glacial till "below the plow layer
has a saturated hydraulic conductivity of less than 0.25 cm/hr. Re-
stricted downward movement of water "begins at the bottom of the plow
layer due to a plowpan which has developed over the years.
Infiltrating water moves through the permeable plow layer. Upon en-
countering the restrictive layer, a perch water table develops. Some
of the water slowly percolates into the subsoil. The remainder begins
to move laterally downslope and may possibly reappear at the surface
some distance removed. A tile trench (filled with permeable material
during construction) which crosses the field perpendicular to laterally
moving water, intercepts a portion of this water on the upslope side,
and discharges it through the tile. One would speculate that since
lateral flow volumes are reduced, due to interception by the trench,
quantitative downward movement of water might also be reduced.
Since water is more rapidly removed from the soil by tile drainage
than by natural drainage in these soils, so is the more rapid removal
of nitrogen and phosphorus. The form in which nitrogen is removed
from the soil is also altered. Within the vicinity of its influence,
artificial drainage tends to achieve an aerobic environment because
of the removal of soil water. Aerobic conditions would favor the ox-
idized form of inorganic nitrogen (NO--N). When these imperfectly
drained soils are not artificially drained, the likelihood of nitro-
gen removal by denitrification is greater than under artificially
drained situations.
The natural pathway of phosphorus transport, like nitrogen is also
altered by tile drainage. In non-tiled drained situations, phosphorus
in solution would move less rapidly in comparison to a more rapid
removal of water via a tile line. Less rapid removal (increased
retention time) and additional percolation of water into the subsoil
would enhance phosphorus fixation. In essence, the quality of tile
effluent is not representative of the quality of soil water that is
naturally transported through the soil profile.
Although one may appreciate the problems encountered with evaluating
tile drainage effluent for given water transport pathways, treatment
comparisons can be difficult to assess. Due to natural soil hetero-
geneity, each respective tile line, although the same diameter and
length, may be draining a proportionally different volume of soil.
If drainage volumes become partially independent of the applied
27
-------
manure treatment, then nitrogen and phosphorus discharges also become
partially independent of these imposed treatments. The investigator
must realize that treatment differences need to be great to be sig-
nificant .
Annual flow and nitrogen and phosphorus discharges in tile effluent
are given in Table 2 for the respective treatments. Because of
the high degree of variability in drainage characteristics, treatment
effects did not significantly influence tile effluent discharges.
Even if the independence between tile effluent discharge and treat-
ment was an overestimate, absolute numerical differences in terms of
nitrogen and phosphorus losses were not very great.
The data of Table 2 are the discharges per single tile line- If one
wants to assume that the drainage areas per tile line are identical,
a calculation on a constant per unit area basis can be made. If it
is assumed that each tile line drains the entire upslope portion of
the plot plus 3 meters on the downslope side, a conversion factor
of 5.23 can be used to calculate nitrogen and phosphorus discharges
on a per hectare basis. Table 3 is a presentation of adjusted tile
effluent discharges on an area basis. The ratio between treatment
means are identical to Table 2 since a constant factor was used for
adjustment. Water and nutrient discharges, however, are approxima-
tely 5 times greater on a per hectare basis, in comparison to a per
tile line discharge.
Selected Runoff Events -
The comparison of various runoff and associated climatological events
serves to point out several important factors which should be con-
sidered when establishing parameters for any system in which the
weather is a variable. This is especially true for land disposal
of animal wastes since runoff is the principal means of nutrient
transport.
The design of manure management parameters for an 'average' year, in
terms of climatic events, is difficult to assess since an average
year exists in definition only. In the same sense, no two climatic
events will be the same nor will the antecedent conditions pertain-
ing to them be the same.
A particular manure management treatment may behave quite erra-
tically from one year to the next since the independent variables
controlling nutrient discharge are in constant oscillation. However,
the comparison of the behavior of manure treatments for any given
climatological event becomes meaningful since a good many of the
independent influences concerning nutrient discharges are acting
similarily.
28
-------
Table 2. PLOW, INORGANIC NITROGEN AND TOTAL SOLUBLE PHOSPHORUS DISCHARGES IN RANDOM TILE
LINES. 1972, 1973.a
Treatment
Time
Winter
Spring
Summer
Rate, t/ha
35
200
Soil mg't
Good
Poor
1972
9&Ua
1378a
857a
ll6Ua
98la
987a
Il68a
Plow, m3
1973
358a
720a
270a
U6la
^37a
3hja
552a
Ave.
671a
10^9a
563a
8lUa
709a
662a
860a
1972
10. Ua
12. 8a
10. 9a
10. 7a
12. la
11. 7a
11. Oa
N, kg
1973
7.0a
10. Ua
5.^a
5.0a
10. 2a
5.7a
9.5a
Ave.
8.7a
11. 6a
8.2a
7.8a
11. 2a
8.7a
10. 3a
1972
0.05a
0.09a
0.17a
O.OUa
0.17a
0.06a
O.lUa
P, kg
1973
O.Sla
0.07a
O.Ola
O.Ola
0.25a
0.03a
0.23a
Ave.
0.19a
O.OSa
0.09a
0.02a
0.21a
O.Oka
O.lja
to
CD
a
Means followed by the same letter are not statistically significant @ 5% level.
-------
Table 3. ADJUSTED FLOW, INORGANIC NITROGEN AND TOTAL SOLUBLE PHOSPHORUS DISCHARGES IN RANDOM
TILE LINES. 1972, 1973.a
Treatment
Time
Winter
Spring
Summer
Rate, t/ha
35
200
Soil mg't
Good
Poor
1972
5150
7213
1*1*86
6093
5135
5119
6lil*
Flow, m3/ha
1973
187U
3769
ll*13
2l*13
2287
1816
2889
Ave.
3512
51*91
291*7
It26l
3711
31*65
1*501
1972
51*. 1*
67.0
57-0
56.0
63.3
61.2
57.6
N, kg/ha
1973
36.6
5U.U
28.2
26.2
53A
29.8
1*9.7
Ave .
^5.5
60.7
1*2.9
1*0.8
58.6
1*5.5
53.9
1972
0.26
0.1*7
0.89
0.21
0.89
0.31
0.73
P, kg/ha
1973
1.62
0.37
0.05
0.05
1.31
0.16
1.20
Ave.
0.99
0.1*2
0.1*7
0.10
1.10
0.21
0.89
CO
o
a
.Flow and quantities adjusted on an area basis "by assuming a constant drainage area for each
tile line.
-------
The rate and timing of manure applications is an important consid-
eration in any manure management scheme. This section will deal with
the response of rate and timing of application for a series of sel-
ected runoff events.
Table k is a listing of the several selected storms for this dis-
cussion. An estimate of the contributing rainfall is necessary for
events resulting from several days of rainfall. The column reserved
for remarks indicates the type of climatological situation that
occurred. Table 5 points out the relative severity associated with
these runoff events. The quantity of runoff and soil loss is cal-
culated as an average over all 2k experimental plots to serve as a
relative guide to severity. The runoff and soil losses are also
calculated in terms of the percent of the annual using the calendar
year for annual computation.
Each runoff event will be discussed separately to bring out the
characteristics of both the precipitation and surface soil condi-
tions .
Figures 7 through 15 are the resultant nutrient losses of inorganic
nitrogen (IH^-I + NOg-N) and total soluble phosphorus in surface
water effluent and total nitrogen and total phosphorus in sediment.
Each figure is self explanatory as to the rate of manure application
and the time of the year the manure was applied. The losses are
averaged over both soil management practices to produce the main
effects of rate and timing. The interaction between rate and soil
management practice will be discussed where appropriate. The ver-
ticle scale for each figure was changed to enhance clarity, there-
fore comparisons of relative magnitudes of nutrient losses from
one figure to the next should be made with caution.
Selected runoff events were chosen on the basis of the type of
climatological event and also to give a broad spectrum over seasons.
The runoff events presented are only a small segment of the total
runoff that occurred over the years. The sum of the individual
events are presented in the section dealing with annual nutrient
discharges.
One random variable which confuses comparisons is experimental plot
to plot variability. It is inevitable that the slopes, infiltration
rates, and internal percolation rates vary from plot to plot. This
means that some of the differences among treatments are not treat-
ment effects per se, but rather the effect of the nature of the
soil to which the treatment was applied. Judgments about whether
affects are due to treatment or are a consequence of plot charac-
teristics are based on an intimate knowledge of the plots themselves
31
-------
Table h. CHAEACTERISTICS OF SELECTED RUNOFF EVENTS.
co
IN3
Storm
no.
15^
2k3
261
288
311
315
338
3^9
371
Runoff
date(s)
2/28-29/72
6/21-26/72
8/27/72
12/H-7/72
3/17-19/73
Vl-6/73
12/22-27/73
2/22-2UM
6/llM
Estimate of Snow-
contributing cover,
rainfall , cm cm
28
17- U
6.8
3.8
6.6 1
8.0
1.2 20
1.3 1
IK 6
Remarks
Snow melt, water equivalent approx.
3.3 cm.
Hurricane Agnes. Max. hourly intensity =
1.5 cm
Maximum hourly intensity = 6.h cm
Sum of 5 day rainfall
Sum of 5 day rainfall
Sum of 6 day rainfall
Snowmelt followed immediately by rain
Snowmelt followed by rain
Total rainfall occurred in 75 minutes.
-------
Table 5. RELATIVE SEVERITY OF SELECTED RUIOFF EVEITS.a
CO
OS
Storm
no.
15U
2^3
261
288
311
315
338
3U9
371
Runoff
dat e ( s )
2/28-29/72
6/21-26/72
8/27/72
12/U-7/J2
3/17-19/73
Vl-6/73
12/22-27/73
2/22-2U/714
6/11/7U
Runoff,
cm
2.08
5-51
0.76
9-91
2.21
1.96
0.25
O.lU
0.22
% of
annual
lit
32
U
5
in
36
5
b
-
Soil loss,
kg/ha
103
1331
181
20
88U
161
3
7
90
% of
annual
3
^7
12
1
77
lit
< 1
-
-
«a
Averaged over all experimental plots.
Data not available for entire 197^.
-------
as well as upon statistical treatment of the data. This type of
soil variability even within a small area is not at all -uncommon. The
larger the watershed, the more difficult it becomes to characterize the
controlling independent variables and to define the inherent variabil-
ity.
Referral from time to time to the treatment schedule of Table 1 in
the section dealing with annual nutrient losses may be necessary to
help orient the reader.
February, 1973 - The first selected event was the result of a snowmelt
that occurred during winter disposal. The first manure application
began on February 15, 1972 for the winter applied treatment. The soil
was frozen and covered with 2 cm of snow. The 35 and 200 t/ha rates
were completed in four days. Upon completion, k& cm of snow fell
which delayed the application of the 100 t/ha rate until February
29. By this time, the snow had increased considerably in density due
to melt, having a depth of approximately 28 cm. This soil surface
condition gave an opportunity to spread manure on dense melting snow
over frozen soil, the worst possible condition that could occur
during winter activity with reference to melting snow and frozen soil.
When the 100 t/ha rate was applied, the machinery cut ruts into the
snow which further enhanced channelization of the runoff water.
Figure 7 shows the extremely large and significant discharges of
nitrogen and phosphorus for the 100 t/ha loading rate in comparison
to the 35 and 200 t/ha rates even though the rate was approximately
halfway between the minimum and maximum amounts applied. Spreading
of manure on deep melting snow is a practice not commonly utilized by
dairy farmers. It is not very often that the soil is able to support
heavy machinery during snow melt periods. In essence, spreading
wastes on deep melting snow is uncommon because of the soil restric-
tion and not due to a management decision.
Although no control plots exist in the experimental design, the re-
maining l6 plots (2k total) slated for spring and summer application
(8 apiece) serve as control plots for this event and are presented in
the upper half of Figure 7- The nutrient discharges from the control
result from the residual nitrogen and phosphorus present in the soil.
It is interesting to note that losses from the 35 t/ha rate for both
surface water and sediment were less than the control. This serves
to denote that low loading rates even on a frozen soil may be within
acceptable tolerances.
Soil management played a very important role in this runoff event,
especially for the 100 t/ha rate. Table 6 is a breakdown of the
loading rate split into the respective soil management practices.
34
-------
o»
10
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CONTROL
WINTER
35
100 200 35 100
LOADING RATE, t/ha/yr
200
o»
JC
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I?
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LU
Cfl
Figure 7- Nitrogen and phosphorus losses from a snownelt
with respect to loading rate. 2/29/72.
event
35
-------
to
Table 6. DAIRY MANURE LOADIIG AND SOIL MANAGEMENT UNDER CONDITIONS OF SNOWMELT AS A
CONSIDERATION IN NUTRIENT DISCHARGE. 2/29/?2a
Loading rate ,
t/ha/yr
35
100
200
Soil
mg't
Good
Poor
Good
Poor
Good
Poor
Surface
N
0.6 a
l.k a
25.1 a
66.2 b
It. 2 a
12.0 b
runoff, kg/ha
P
0.2 a
0.1* b
5-0 a
12.9 "b
1.9 a
U.8 b
Sediment ,
N
0.02 a
0.08 a
2.91 a
1.18 b
0.2U a
0.19 a
kg/ha
P
0.01 a
0.06 a
0.58 a
0.82 a
0.11 a
0.07 a
Values followed by the same letter are not significantly different @ 5% level.
-------
It is actually the interaction between rate and soil management.
There is considerable difference between good and poor practice
(return of plant residues vs their removal for the past l6 years) at
the two higher rates of application. The greatest loss occurred at
the 100 t/ha rate on a poorly managed soil. Long term poor soil
management practices have made this plot relatively erosive. Lack
of underdrainage for both management practices for this rate of
application further compounds the problem by not providing partial
relief for excess water.
June, 1972 - The runoff event of June 26, 1972 resulted from Hurricane
Agnes. Rainfall was 17.^ cm over a five day period with moderate
intensities on an already saturated soil. The long duration of the
storm caused considerable damage to the landscape. At the time of
this event, the spring and summer applications of manure had been
applied. The winter and spring treatments had been plowed down and
the summer applied manure remained on the soil surface. The corn
was less than 0.3 meters high. The frequency of this rainfall event
had been estimated by climatologists to occur once in 100 years.
The general behavior of nutrient losses for this event are quite
erratic for the rate and timing of application (Figure 8). For sur-
face water nitrogen and phosphorus contents, the output in the
effluent is fairly constant for the summer application regardless of
the rate, owing to the fact that the manure is exposed on the soil
surface and sufficient nitrogen and phosphorus is available for
removal. The erratic behavior of the rate and timing treatments
as a result of a hurricane can be explained by the very important
fact that once a soil becomes saturated, the imposed treatments no
longer play an important role on runoff. The quantity of runoff
and sediment becomes a function of the infiltration rate and trans-
mission (percolation) rate of water into and through the soil
profile for the various plots, or more broadly, for the heterogeneous
soils within a watershed. To cite an example of this heterogeneity
of soils among experimental plots, the sediment loss of nitrogen
and phosphorus for the spring applied 200 t/ha is inconsistent in
comparison to all other treatments. One of the experimental plots
associated with the 200 t/ha treatment has a complex slope (surface
topography) which runs in two directions and is more strongly sloping
than any other plot in the experiment. Due to slope complexity, many
of the corn rows ran up and down the slope. Since runoff and erosion
is a function of slope, one would expect an increase in nutrient loss
with an increase in slope gradient. This single runoff event on the
aforementioned plot accounted for 83 and 70% of the total nitrogen
and total phosphorus loss, respectively, in sediment on an annual
basis. This data should not be ignored or discarded as too complex.
It serves to illustrate the kind of results that can be expected in a
watershed of varying topography and soil types.
37
-------
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In general, the nutrient discharges in sediment was significantly
lower for the summer application. The mulching effect (reduction of
soil exposure) of manure lying on the surface was efficient in reducing
soil loss.
August, 1972 - Nutrient losses during an intense rainstorm on August
8, 1972 is presented in Figure 9. The rainstorm delivered 6.8 cm of
water of which 6.U cm fell in one hour. According to U.S. Weather
Bureau Standards (72) for short duration storms (less than 2 hrs),
this rainfall event was classified as excessive with a probability
of 1 in 50 years. Excessive, for short duration storms of 2 hours
or less, is defined as:
A = [t + 20 x 2.5*0/100
where A = accumulated depth of rainfall in time t
t = time or duration of storm.
For any event where t = 60 min, 'A' must be greater than or equal
to 2.03 cm in order to be classified as excessive.
When this event occurred, the corn crop was at maximum height and
nearly fully matured. With such a high intensity rainfall one would
expect severe erosion. Referral to Table 5 shows that the average
runoff was considerably less than during the previous winters snowmelt
and the spring hurricane. The presence of an almost complete canopy
of corn over the soil surface was responsible for reducing the kin-
etic energy of rainfall impact. The presence of vegetative cover is
extremely important in protecting the soil against erosion.
The nutrient losses as illustrated in Figure 9 are approximately an
order of magnitude lower than the two previous runoff events.
Statistical analysis of these data show that no real differences
between rate and timing of application exist for nitrogen in surface
water and nitrogen and phosphorus in sediment. Phosphorus discharges
in surface water, although small in magnitude, was significantly higher
for the summer application, owing to the fact that exposure of manure
on the soil surface at the higher rate resulted in a greater delivery
of phosphorus.
The soil management variable influenced total nutrient losses in
surface runoff but had no significant affect on sediment losses. On
the average, poor soil management resulted in a 2 and U fold increase
for nitrogen and phosphorus, respectively, in surface water in com-
parison to well managed soils.
39
-------
0.4
D
x:
0.2
or
i
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WINTER
ruffe
g 0.4
0.2
O
CD
or
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SPRING
it 0-4
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0.2
SUMMER
ru
71
35 100 200 35 100
LOADING RATE, t/ha/yr
200
o
o»
a.
I
o
o
z
UJ
O
UJ
2 co
Figure 9- Nitrogen, and phosphorus losses from an intense
rainstorm with respect to loading rate and time of
manure application. 8/27/72.
40
-------
December,1972 - The last event selected for 1972 occurred in
December and resulted from a five day rainfall, totaling 3.8 cm, on
non-snow covered soil. Of special interest was the response of the
time lapsed since disposal and the resultant nutrient discharges.
The event occurred on December 7, 1972 almost one year since the pre-
vious winter disposal and 8 and 7 months after the spring and summer
applications, respectively. The manure from the summer application
still remained on the soil surface. Total nutrient losses (Figure 10)
are quite small and nearly approximate the discharges resulting from
the intense August storm (Figure 9)- More specifically, the summer
application resulted in significantly greater discharges of nitrogen
and phosphorus than its counterparts. The exposure of soluble nutrients
on the soil surface versus the plowing down of manure was still showing
an influence at this later date.
Phosphorus losses in runoff were lower for the minimum rate and
showed no real difference between the two higher rates. The same
was true of nitrogen in runoff at the lower rate, but again the 100
t/ha application, regardless of the time of application yielded
greater nitrogen losses (Figure 10). The absence of underdrainage,
particular to this treatment, is influential in increasing runoff.
With increased runoff and a reduction in the leaching of soluble
nitrogen, because of the lack of tile drainage, increased discharge
resulted.
The resultant sediment losses of these two nutrients showed that,
there are insignificant differences with regard to the overall
rates of application. The interaction between time of application
and the rate applied showed that the spring applied 200 t/ha treat-
ment had the greater discharge of nitrogen and phosphorus. The
physical characteristics of one of the plots associated with this
treatment (slope gradient) has previously been mentioned in the
discussion dealing with Hurricane Agnes (Figure 8). The same prin-
ciple is operating in this case. In reality, the relative differences
are small with maximum losses never exceeding 0.5 kg/ha.
The soil management variable was influential for this runoff event.
By this time, the corn had been harvested. Poorly managed soils
were void of plant residue (corn harvested for silage - only stubble
remains). The well managed treatments contained a good cover of
plant residues (corn harvested as grain - stover remains) on the
soil surface which aided in reducing erosion. Table 7 shows the
reduced losses with good soil management practices as averaged over
all manure treatments.
At the conclusion of this runoff event, one complete manure treatment
cycle had been made. On January 12, 1973, the second winter application
41
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2
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-------
Table 7. THE INFLUENCE OF SOIL MANAGEMENT ON NUTRIENT DISCHARGE
DURING WINTER RAINFALL. 12/T/72a
Soil
mg't
Good
Poor
Surface runoff,
N
0.10 a
0.28 b
kg/ha
P
0.02 a
0.06 b
Sediment , kg/ha
N P
0.02 a 0.01
O.ll* b 0.08
a
b
a Means followed by the same letter are not significantly different
% 5% level.
43
-------
of manure began and was completed on January IT- At the time of
disposal, the soil was frozen to approximately 10 cm with a 2.5 cm
snow cover. The beginning of the second cycle affords an opportunity
to look at the residual effects of manure from the prior cycle.
March, 19T3 - The first runoff event selected for 1973 occurred on
March 19 due to an accumulated 6.6 cm of rainfall over a five day
period. At this time there was approximately 1 cm of snow cover
upon a non-frozen soil. The discharge of nitrogen in surface water
for this event (Figure 11) was not significantly greater for the
winter application in comparison to the previous applications of
last spring and summer. The residual nitrogen from prior applica-
tions was great enough to approximate the losses incurred from a
very recent winter application. From Figure 11, the range of
nitrogen discharge was approximately 0.25 to 1.25 kg/ha.
Phosphorus, on the other hand, displayed a higher discharge in sur-
face water for the winter application because of readily available
soluble phosphorus. The residual effects of phosphorus from the
first cycle (spring and summer application) was not as influential
as nitrogen in supplying soluble material in runoff. Future avail-
ability of insoluble phosphorus from manure, like nitrogen, is pro-
vided by chemical and biological transformation from the insoluble
to the soluble phase. However, unlike inorganic nitrogen, phosphorus
is not highly mobile and soil fixation can render much of the soluble
portion as unavailable.
The average effect of the rate of application showed no differences
with respect to nitrogen but did increase a significant amount for
phosphorus as the rate increased.
The sediment contents from this runoff event as influenced by treat-
ment, was not as well defined as the material in surface runoff. In
general terms, neither the rate or timing of manure application had
any significant influence on nutrient losses. The peak nitrogen
and phosphorus losses are noted for the winter applied 100 t/ha
and the spring applied 200 t/ha treatments.
The above sediment data for these two isolated treatments is presented
in Table 8 for clarification. It is evident from this table that the
poorly managed plots associated with these two treatments was respon-
sible for the higher average loss for the rate of application. The
well managed soil for the winter and spring treatments contained
nitrogen and phosphorus losses in sediment very much in line with
the recorded losses for the 35 and 200 t/ha winter rates (Figure 11).
In essence, improved soil structure through careful soil management
is extremely beneficial.
44
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35 100 200 35 100
LOADING RATE, t/ha/yr
200
Figure 11. Nitrogen and phosphorus losses from winter rain-
fall (6.6 cm) with respect to loading rate and
time of manure application. 3/19/73-
45
-------
Table 8. INFLUENCE OF SOIL MANAGEMENT ON THE DISCHARGE OF TOTAL
NITROGEN AND TOTAL PHOSPHORUS IN SEDIMENT FOR TWO ISOLATED
TREATMENTS. 3/19/T3a
Time of
applic .
Winter
Spring
Loading
rate, t/ha
100
200
Soil
mg't
Good
Poor
Good
Poor
Sediment
N
1.8 a
12.8 b
3.U a
13.5 b
discharge, kg/ha
P
0.8 a
1*.8 b
1.6 a
5.8 b
Values followed by the same letter are not significant
level.
46
-------
Although the 200 t/ha rates appeared on experimental plots that
contain a tile line for underdrainage, the poorly managed soil for
the spring application is inherently more erosive because of its more
complex slope in addition to having a poor soil structure due to
management. The -well managed plot associated with this treatment
(Table 8) displayed nutrient losses in sediment parallel with other
spring treatments (Figure 11).
The soil management variable as averaged over all rates and time of
application for this event, unlike many of the others, had no
significant influence on surface runoff discharges of nitrogen and
phosphorus. Sediment losses of these two nutrients, however, were
strongly influenced by soil management, with a 150$ and 1^0$ reduc-
tion in nitrogen and phosphorus, respectively, for good management.
April, 1973 - The runoff event of April 6, 1973 (Figure 12) occurred
just prior to the spring application and affords another look at
runoff quality after winter spreading and the effects of residual
nitrogen and phosphorus from applications made prior to the last
growing season. Runoff began on April 1 activated by 2.8 cm. of
rainfall. Rainfall and runoff lasted 6 days with a total of 8.0 cm
of precipitation. Total average runoff approximated the previous
selected runoff event, but soil loss was substantially lower, even
though precipitation was l.U cm greater (Tables U and 5)- The com-
bination of these two runoff events accounted for 77% of the annual
runoff and 91$ of the annual soil loss for 1973.
The residual effects of nitrogen in surface water from previous
applications (spring and summer of 1972) was still making an im-
portant contribution to nitrogen discharges. Statistical comparisons
show that overall nitrogen losses are significantly lower for the
winter application in comparison to summer applications but are
equivalent to discharges resulting from spring applications. The
major difference between the spring and summer treatments was that
the manure applied in the spring had been plowed down while summer
applied treatments contained manure exposed on the soil surface.
Surface exposure of manure would enhance nutrient removal to a greater
extent than manure that had been plowed down. This is especially
evident with the greater phosphorus discharges for the summer appli-
cation in comparison to those made in the spring.
Phosphorus discharges in surface water effluent were considerably
higher for the very recent winter application, which was exposed on
the soil surface at the time of this event. The initial output of
phosphorus is high for freshly spread manure. Total soluble phos-
phorus contents of dairy manure for this winter application was 0.30$.
This soluble fraction accounted for 60$ of the total phosphorus in
47
-------
1.0
|0.5
oT
i
ID
_J
° i n
V) I-'-'
ru
Q
<
11
UJ
s
to
35 100 200
LOADING RATE,
35 100
t/ha/yr
200
Figure 12. Nitrogen and phosphorus losses from spring rain-
fall (8.0 cm) with respect to loading rate and
time of manure application. W6/73-
48
-------
the applied manure (Table A8, Appendix). Prior leaching and soil
fixation of phosphorus accounted for the lower discharge of phos-
phorus for the previous year's spring and summer application.
Residual nitrogen in manure played an important role in water quality
at a later date. Residual phosphorus, on the other hand, is less
significant.
Average sediment discharges of these two elements with regard to
the time of application were essentially the same from a statistical
viewpoint. Sediment losses for the runoff event of April 6, 1973
(Figure 12) are plotted against an expanded scale of three-fold in
comparison to the prior runoff event of March 19, 1973. Maximum
nutrient losses of the latter event approximate the minimum discharge
of the former runoff event.
December, 1973 - The remaining spring and summer season was relatively
dry, producing only two additional runoff events before July, 1973.
There was no recorded runoff from July until the last week in December.
The runoff event of December 27, 1973 was selected to further study
the magnitude of nutrient losses during the winter. On the whole,
this event, as presented in Figure 13, accounted for only 5% of the
annual runoff and 3% of annual soil loss (Table 5). From a nutrient
loss standpoint this event was inconsequential, but serves to illus-
trate expected losses from minor snowmelt events accompanied by rain-
fall (1.2 cm) on a non-frozen soil.
Treatment comparisons for this event are difficult to access since
less than 50% of the treatments produced runoff. With no runoff,
discharge quantities are recorded as zero.
Runoff occurred two weeks prior to the beginning of the third winter's
manure application. Nutrient losses are minor in comparison to previous
events. Average nitrogen and phosphorus losses for both runoff and
sediment appeared to correlate to the lapsed time since manure dis-
posal (summer > spring > winter).
February, 197*1 - The next to the last event (Figure lU) to be dis-
cussed, occurred on February 2k, 1971* as a result of 1.3 cm of rain-
fall and associated snowmelt resulting from an accumulation of 1.0 cm.
Much like the runoff event of December 27, 1973, nutrient losses were
minimal. The winter of 197^, like 1973, did not result in any major
49
-------
2-
o
JC
X.
o>
CL
I
UJ
_)
CD
ID
_1
O
to
-------
o I
o»
Q.
I
LU
_J
m
O
cn
O
OC
O
U.
UL
O
WINTER
0.2
o>
JC
or
i
SPRING
0.2°
O
TOTAL -
2
LU
SUMMER
0.2 S
xxxxx
0.1
35 100 200 35 100 200
LOADING RATE, t/ha/yr
Figure ih. Nitrogen and phosphorus losses from snowmelt
and rainfall with respect to loading rate and
time of manure application.
51
-------
snowmelt events. The presentation of these data will show expected
nutrient discharges from snowmelt after a recent winter application
(made in mid-January) in contrast to applications made prior to the
last growing season.
Runoff occurred on slightly less than 50% of the plots with many treat-
ments having a discharge quantity equal to zero. Runoff was extremely
minimal from the winter applied treatments and is probably due in part
to the recent cover of manure on the soil surface. This mulch would
aid in absorption and retention of rainfall or snowmelt. The only
runoff produced from the winter treatments were from the poorly managed
plots at the minimum and maximum rates of application, accounting for
the slight discharges of nitrogen in surface water and both nitrogen
and phosphorus in sediment.
In general, residual losses of'these two elements from the past spring
and summer application contributed more to surface water and sediment
discharges than a recent winter application.
June, 197U - The last runoff event to be discussed occurred on June 11,
197^ twelve days after the summer application was applied on top of
growing corn. The past winter and spring applications had been plowed
down. Rainfall was intense with U.6 cm occurring in 75 minutes.
According to U.S. Weather Bureau standards for short duration storms
(<2 hrs), this rainfall event was classified as excessive, approxi-
mating a 1 in 10 year probability. At this time, the corn was approx-
imately 10 cm high.
Nutrient losses in surface runoff as presented in Figure 15 were
quite small. Inorganic nitrogen did not exhibit a significant change
relative to the rate or timing of manure application. Phosphorus on
the other hand showed a small but significant increase in runoff water
for the summer application, owing to the very recent addition of manure.
Total phosphorus and total nitrogen in sediment did not show itself to
be significantly influenced by the timing or rate of application.
Although this event was caused by a fairly intense rainstorm, erosion
losses were at a minimum. In comparison, this storm was not as in-
tense as that occurring on August 27, 1972. Total contributing rain-
fall for the August 1972 storm was 1.5 times greater with the average
runoff and soil loss being 3-5 and 2.0 times greater, respectively in
comparison to this intense June 197^ storm.
Trends - Diffuse sources of nutrient discharges are difficult to
characterize and assess because of the normal variability that is
encountered in an agricultural watershed. Although many inconsisten-
cies may appear with nutrient loss measurements from non-point sources,
52
-------
o
£
N^
o>
JC
or
i
uj
_i
CD
3
_l
O «
tn 2
_i
i'
JC
oT
i
SPRING
n
2°
o
SUMMER
Cta
35
Figure 15-
100 200 35 100 200
LOADING RATE, t/ha/yr
Nitrogen and phosphorus losses from an intense
rainfall (^.6 cm in 75 min.) with respect to
loading rate and time of manure application.
6/nm.
53
-------
many consistent and significant trends are evident.
The runoff event of February 1972 clearly demonstrated that common
sense must dictate ones winter disposal activities. High rates of
manure loadings over extensive areas, as the result of cleaning out
manure storage facilities, as this experiment has tempted to simulate,
during snowmelt activities is inexcusable. Lower loading rates, in
the neighborhood of 35 t/ha during non-snow melt periods, has shown
nutrient discharges to be within acceptable tolerances when compared
to fields receiving no manure (Figure 7)-
The soil and vegetative cover on disposal fields are all important.
Erratic nutrient discharges, in relation to the rate or time of
application, can be encountered because of the influence of soil
heterogenity among disposal fields. The hurricane in June of 1972,
pointed out that when the soil is saturated, the influence of rate
and timing of manure applications is masked by many independent soil
variables which strongly influence runoff. The same was true even
when soils are not saturated prior to or during a rainstorm, but to
a lesser degree.
The importance of vegetative cover during intense rainstorms is
clear cut in terms of soil protection and a protective canopy to aid
in the reduction of raindrop impact. This was demonstrated as the
result of the intense August 1972 and June 197^ rainfalls. Vegeta-
tive residues left on the soil surface (good soil management) had
also proved to be very beneficial in reducing nutrient discharges
on imperfectly drained soils.
The residual nitrogen and phosphorus from previous applications had
some influence on nutrient discharge the following year. Reference
to the events of March 1973, April 1973, December 1973 and February
197^ showed that residual nitrogen exhibited a greater availability
in comparison to residual phosphorus. Future availability of in-
soluble phosphorus from manure, like nitrogen, is generated by
mineralization from the insoluble organic to the soluble inorganic
phase. However, unlike inorganic nitrogen, phosphorus is not highly
mobile and soil fixation can immobilize much of the soluble inorganic
fraction.
A series of correlation and regression coefficients have been calcu-
lated for the nine individual treatments (3 disposal periods x 3
application rates) emphasized in this section. Tables 9 and 10 are
estimates of these coefficients as a result of the nine selected
runoff events.
54
-------
Table 9- CORRELATION AMD LINEAR REGRESSION COEFFICIENTS FOR THE DIS-
CHARGE OF INORGANIC NITROGEN IN SURFACE RUNOFF RESULTING
FROM NINE SELECTED EVENTS.
Time of
application
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
Means
runoff (X), m3
UU.8
80.1
38.1
Uo.5
83.1
6U. 5
63.5
122.9
90.0
N(Y),kg
0.2J4
2.W
0.1*5
0.13
0.1*5
0.1*7
OA6
o.i+o
0.1*7
a
r
0.90
0.51
0.25
0.88
0.89
0.63
0.95
0.91
0.89
S.E.b
0.19
5.58
1.11
0.12
O.U2
0.85
0.25
0.26
0.5!+
c
a
- .09
- .71
.20
- .08
- .21
- .12
- .15
- .07
- .16
bd
.007
.01*0
.006
.005
.007
.009
.010
.001+
.007
a Correlation coefficient, >_ .67 P <§ .05 for 7 d.f.
Standard error of estimate.
Intercept
d Slope
55
-------
Table 10. CORRELATIOI AND LINEAR REGRESSIOI COEFFICIENTS FOR THE
DISCHARGE OF TOTAL SOLUBLE PHOSPHORUS IN SURFACE RUNOFF
RESULTING FROM NINE SELECTED EVENTS.
Time of
application
Winter
Spring
Summer
Q
Correlation
b
Rate,
Means
t/ha runoff (X) ,m3
35
100
200
35
100
200
35
100
200
kk
80
38
ko
83
6k
63
122
90
coefficient
Standard error
Intercept .
d Slope
,9
.2
.1
• 5
.1
.5
.k
• 9
.1
,1-67 P £
i_
P(Y),kg
o.oU
0.^7
0.22
0.01
2.01
0.19
0.83
0.08
0.09
I .05 for
a
r
0.3^
O.U
0.20
0,97
0.20
0.6l
-0.17
0.93
0-79
7 d.f.
S.E.° a°
0.05
1.15
o ,k6
0.001
6.27
0.3^
2 .kk
0.07
0.12
.02
-.07
.13
-.0002
-91
-.Ok
1.16
-.05
-.Ok
bd
.0003
.007
.002
.0001
.012
.OQk
.005
.001
.002
of estimate.
56
-------
The relationship between runoff and nitrogen discharge (Table 9)
showed a significant correlation (r) in 6 out of 9 treatments.
Runoff versus phosphorus discharge (Table 10) showed a significant
relationship in only one-third of the treatments. Even though the
description of a correlation remains highly contingent upon what is
being assessed, it is still useful to have some consistency of
terminology in describing the magnitude of the coefficient itself.
Guilford (28) offers a rough guide:
r = < .20 slight; almost neglible relationships
r = .20-.kO low correlation; definite but small relationship.
r = .hO-.JO moderate correlation; substantial relationship
r = .70-.90 high correlation; marked relationship
r = > .90 very high correlation; dependable relationship.
Perhaps a more important indication of the strength of these relation-
ships would be to consider the standard error of the estimate (S.E.)
or the standard deviation of Y holding X constant. In most instances,
the standard error exceeds the mean of Y, strongly indicating a
large degree of variation.
The rate of manure application has always been of interest to the
researcher when dealing with nutrient losses. Figures 16 and IT
illustrate the relationship between nutrient discharge and quantity
of runoff for nitrogen and phosphorus at each rate of application
over the nine runoff events. It is obvious from these figures that
a strong relationship is non-existent. The data points are scattered
considerably because of varying soil surface conditions, which in-
fluence runoff, and a large amount of variability in nutrient con-
centration, depending on the time of the year runoff occurs in
relation to the time lapsed since manure disposal. Tables All -
Alk of the Appendix denotes runoff and nutrient concentrations for
the presented data. Average concentrations are determined only from
plots having runoff whereas the quantity of nutrient discharge takes
zero discharge into account.
It is not within the scope of this experiment to construct computer
simulation models for nutrient discharge from manured landscapes.
Conceivably, models could be developed based on these findings plus
a well thought through conception of the necessary independent para-
meters influencing nutrient removal.
Winter Disposal -
There has been much controversy in the past about the land applica-
tion of manure during the winter season. Many feel that nutrient
loadings from winter applied manure will be greater than from
applications made during the spring, summer or fall seasons.
57
-------
14
10
6
35 t/ha
o>
.*:
UJ
O
-------
o>
JC
10
/
6
4
2
UJ
o
(T
I
O
co
o
CO
OC.
o
0.
CO
o
X
Q.
UJ
CD
ID
Y=.06 4.004 (m3)
r=.4i
10
y
6
4
Y=.35+.006(m3)
r-.26
• •••>«
10
O
.0(3(m3)
35 t/ha
• 100 t/ha
200 t/ha
0
Figure 17.
100
300
200
RUNOFF, m3
Discharge of total soluble-P in runoff for nine
selected events with respect to rate of manure
application.
400
59
-------
In previous discussions, annual losses of nitrogen and phosphorus
over a two year period from winter applications were compared to
those losses from spring and summer applications. A brief summari-
zation of the aforementioned data would be helpful to refresh the
readers memory. The cumulative losses of nitrogen and phosphorus
during 1972 and 1973 in sediment from winter applications were not
statistically greater than losses from spring and summer applications,
With respect to soluble nitrogen in surface water, there was a sig-
nificant increase from winter applications over spring and summer
disposal in 1972, but any real differences in 1973 were non-exist-
ent. In fact, during 1973, losses of inorganic nitrogen from winter
applied plots were equal to the loadings from spring applications
and somewhat less than those incurred from fields receiving a
summer application. However, soluble phosphorus loadings in sur-
face runoff were significantly greater from winter applied treat-
ments, for both 1972 and 1973, in contrast to spring and summer
applications.
The following discussion will center on the losses of nitrogen and
phosphorus in surface water and sediment associated with various
rates of applied manure during the winter for three consecutive years.
The main emphasis will be placed on the rate of application and the
variation that can be expected from one year to the next. The field
experiment actually began in February 1972. January 1 was selected
as a starting point, as a matter of convenience, and April 1 for
cessation of winter activity.
A comparison of several weather parameters, as summed over the months
of January, February and March, for a three year period are given
in Table 11. From these data, the winter of 1972 appears to tie
fairly typical of expected precipitation and snowfall, whereas
1973 and 197^ are somewhat below average, especially for snowfall.
The striking difference between years is in the number of days the
soil was frozen and the number of days there was a cover of snow over
the soil surface. During 1972, the soil was frozen for 62 days
during the three month period in comparison to 12 days for 1973 and
zero days for 197^+ • These soil temperatures were taken at the
weather station on the farm at a 10 cm depth under sod. A dense sod
cover would tend to insulate the soil to a greater degree than would
corn stubble, as was present on the experimental plots. The reported
number of days in which the soil was actually frozen may be an under-
estimate. In addition, the soil surface could be frozen although
the 10 cm depth may be above freezing. Nevertheless, the number
of days of frozen soil under sod at a 10 cm depth may be meaningful
in relative comparisons of the three years.
60
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Table 11. COMPARISON OF SEVERAL WEATHER PARAMETERS FOR A THREE YEAR
PERIOD. SUM OF JANUARY, FEBRUARY AND MARCH.
Total precip, cm
Snowfall , cm
Frozen soil, days
Snow cover, days
1972
17,5 (+ 0.6)a
135 (+ 16)
62
75
1973
15.9 (- 1.0)
35 (- 83)
12
39
197^
15.1*
80
0
6k
(- 1.5)
(-38)
a Deviation from lU and 2U year means for precipitation and snowfall,
respectively.
b Average daily soil temperature = 0°C at the 10 cm depth under sod.
61
-------
The cumulative losses of nitrogen and phosphorus in surface runoff
from January 1 to April 1 for 1972, 1973 and 197^ are given in
Figure 18. There is a marked increase in nutrient losses in 1972
over those occurring in 1973 and 197^- Statistical evaluation of
these data have shown these differences to be meaningful. For both
nitrogen and phosphorus, nutrient losses between 1973 and 197^ were
not significantly different with regard to the year and rate of
application.
The greater losses incurred in the winter of 1972 in comparison to
1973 and 197^ is due to a complex series of circumstances. Expla-
nation of these circumstances existing in 1972 is part fact and
part speculation. The factual portion deals with the weather con-
ditions existing at the time of disposal. Figure 18 shows the
tremendous increased loss of nitrogen and phosphorus associated
with the 100 metric ton/ha rate. The 35 and 200 t/ha rate were
applied on frozen soil being void of a snow cover. Almost im-
mediately, 1*8 cm of snowfall had covered the manure, thus delaying
the disposal of the 100 t/ha rate for almost two weeks. When
the snow had thawed enough, the 100 t/ha rate was applied on 7-5-
10 cm of dense melting snow over frozen soil; a disposal condi-
tion exemplifying the worst possible manure management practice,
but allowing for collection of data under extreme winter con-
ditions .
The first snow melt event occuring after the disposal of the 100 t/ha
rate accounted for 72% and 88% of the annual loss of nitrogen and
phosphorus, respectively, in surface runoff for this treatment. The
poor soil management plot associated with this rate had approxi-
mately 3 times the nitrogen discharge and 2 times the phosphorus dis-
charge in comparison to the well managed plot. The excessive nutrient
losses associated with this particular treatment was not a reflection
of the rate of application, but rather a direct influence of the
weather and soil surface conditions present at the time of dis-
posal. For further analysis of this runoff event, refer to the
section dealing with selected runoff events. If it were not for
this severe disposal condition, it would be safe to speculate that
the loss of nitrogen and phosphorus from the 100 t/ha rate would at
least approximate the losses resulting from the 200 t/ha applica-
tion. It is highly unlikely that it is a common practice for
dairy farmers to spread moderately high rates of manure over ex-
tensive areas consisting of melting snow overlying frozen soil.
The speculative portion of why nutrient losses during 19J2 were
greater than 1973 and 197^ is "based on the tabulated data of Table
11. It appears that January to March of 1972 was fairly typical
of the average precipitation and snowfall than can be expected.
62
-------
1972
1973
53
__
o / Kw*
»_
—
n
•MHI
nn
i «7i ~r
I—I ^^ i— j ^,
100 200 35 100 200 35
LOADING RATE, t/ha/yr
100 200
0
£
V.
j: '
tn"
3 3
Qt
O
X
CL 2
en c
O
£ ,
1972 1973 1974
- a
—
n
WM
n [1 H
35 100
Figure 18.
200 35 100 200 35
LOADING RATE, t/ha/yr
100 200
Three year comparison of inorganic nitrogen and
total soluble phosphorus discharge in surface
runoff due to winter disposal. Cumulative
losses are from January 1 -April 1.
63
-------
During the same time period in 1973 and 197**, precipitation, and
especially snowfall, deviated "below what is considered average.
In addition, 1972 had a much greater number of days in which the
soil was frozen. With a greater amount of precipitation and
occuring days in which the soil remains frozen (1972) one would
expect a greater amount of runoff and subsequent nutrient losses.
For modest rates of application (35 t/ha) , nutrient loss dif-
ferences with respect to year were not significantly different for
either nitrogen and phosphorus in surface water effluent. This low
rate of application may well fall into the acceptable range, when
standards are established, for nutrient loadings even in the
severest of winters .
The discharge of sediment nitrogen and phosphorus as illustrated in
Figure 19 clearly shows a significant rise in nutrient loadings
during 1973 over 1972 and 197** • This is the reverse of what occur-
red with respect to nutrient contents in surface water effluents.
That is, nitrogen and phosphorus loadings from surface water was
significantly higher in 1972 in comparison to the other years. The
lack of correlation between surface water and sediment loadings with
respect to year is evident when comparing Figures 18 and 19-
It was postulated that surface water loading was greatest during
1972 because of the more nearly normal amount of precipitation as
well as a greater number of days when the soil was frozen. With
this being the case, one would expect more runoff. When dealing
with sediment discharges, although a function of runoff, the con-
dition of the soil surface is all important. With a given amount of
precipitation, sediment yields would be greatest on an exposed
surface as compared to an unexposed surface for obvious reasons.
Referring back to Table 11 , the 1973 winter had the lowest number of
days in which the soil was covered with snow. In theory, soil pro-
tection from rainfall impact during winter rains was lower for 1973
in comparison to 1972 and
The greatest amount of sediment discharged in 1973 occurred from a
runoff event lasting 3 days (March 17-19) as a result of 6.6 cm of
precipitation over a 5 day period, mostly in the form of rain. At
the onset of runoff, the soil was without snow cover. The resul-
tant sediment yield from this event contributed greatly to the
cumulative three months loss. In fact, the sediment yield from this
runoff event under snow free soil was greater than the sediment
losses experienced during the snow melt event of 1972 when manure
was spread on top of melting snow. Snow cover in itself forms a
barrier to reduce soil erosiveness. A complete discussion of the
64
-------
1972
1973
1974
JC /
ft
S3
CD
O
-------
aforementioned runoff events can be found in the section dealing
•with selected runoff events.
The nitrogen and phosphorus discharges as it relates to the loading
rate of manure (Figure 19) were not significantly different in
1972 and 19TU. The 100 t/ha loading rate during the winter of
1973 yielded a significantly greater amount of nitrogen and pho-
phorus in comparison to the 35 and 200 t/ha rates. It has been
mentioned before that the plots containing the 100 t/ha rate do
not contain a drain tile and runoff losses may be biased upward.
Nutrient Concentrations -
Total nutrient delivery, a function of runoff volume and nutrient
concentration, should be used as the criteria in developing manage-
ment schemes for land disposal. Average nutrient concentrations,
although complex to evaluate, can be used as an additional tool in
evaluating land treatments if one accepts and understands the tremen-
dous amount of variability that will be encountered from one drainage
event to the next. In addition, frequency distributions of these
nutrient contributions can be used in part to compare the relative
behavior of several treatments under given conditions.
The following discussion will deal with nitrogen and phosphorus con-
centrations in drainage water from both surface runoff and tile
effluent. The liquid fraction was chosen because of the more tho-
rough understanding and already established environmental standards
for potable water, especially for ammonium and nitrate nitrogen (l8).
Surface runoff - Calculations of mean nitrogen and phosphorus con-
centrations and associated variability have been made for two
complete manure application cycles (1972, 1973). The third cycle is
presently underway. Tables 12 through 15 present these nutrient
concentrations.
Ammoniacal nitrogen - The most variable nutrient constituent in run-
off was ammoniacal nitrogen (Table 12). The greatest mean concentra-
tions were associated with the winter 100 t/ha and 200 t/ha treatments,
The extremely high concentrations at the upper end of the range was
responsible for the larger average concentration. Ammonium concen-
trations of this magnitude (100+ ppm) were not commonplace. Out of
138 observations, only one runoff event had a concentration exceeding
100 ppm for the 200 t/ha rate and two observations out of l6U occur-
ring for the 100 t/ha rate (Figure 20). These three outlying ob-
servations all occurred from winter disposal (Figure 21), at the two
higher rates of application, as a result of a snow melt event of
February 1972. This dairy manure, having 20-25$ of its total nitro-
gen in the form of ammonium (Tables A7 and A8, Appendix) at the time
66
-------
Table 12. AMMONIUM NITROGEN CONCENTRATIONS IN SURFACE RUNOFF OVER
A TWO YEAR PERIOD. 1972, 1973.
Time of
applic
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
Obs
91
36
U7
101*
68
50
67
60
1*0
Mean,
Ppm
1.07
8.21*
1*.1*9
0.29
0.30
1.28
0.73
0.21
0.19
Standard Coeff of
deviation variation %
3.03
26.22
21.21
1.01
1.05
It. 01
2.3l*
0.22
0.3U
283
318
1*72
3^5
35^
312
323
108
173
Range
.001*
.010
.010
.010
.001
.001
.010
.003
.001
- 20,3
- 115.5
- 3M.3
- 9-8
- 8.2
- 22.7
- lU.8
- 0.8
- 1.6
67
-------
of spreading, can contribute sufficient amounts of EFH^-N to runoff
waters if runoff occurs almost immediately after manure application.
Lauer, et_ al_.* have demonstrated that ammonia volatilization can
occur rapidly after surface application, with ammonia having an
approximate half life of 1.9 days at the low rate of application
(35 t/ha) and 3.5 days at the higher rate (200 t/ha).
Manure that was applied during the winter of 1972 was either immed-
iately covered with snow before the next runoff event or was applied
directly on top of melting snow. These two conditions are not con-
ducive to significant depletions of ammonia by volatilization before
becoming solubilized in runoff water.
Ammonium concentrations decreased rapidly with increasing lapsed
time since manure disposal. Approximately 80+% of the frequency of
ammonium concentrations were less than 1.0 ppm (Figures 20 and 21).
Nitrate nitrogen - Average nitrate nitrogen concentrations in surface
runoff (Table 13) were more nearly uniform with respect to treatment
than was ammonium nitrogen and exhibited a lesser degree of variation.
Unlike ammoniacal nitrogen, nitrate does not comprise a significant
portion of the total nitrogen in fresh manure, hence discharge of
nitrate into surface runoff is contingent upon the rate of minerali-
zation of the organic fraction and biological and or chemical trans-
formation of existing ammonium nitrogen.
The frequency distribution as illustrated in Figures 22 and 23 showed
that roughly 90$ of the nitrate nitrogen in runoff was less than the
established standard of 10 ppm for potable water. The frequency of
nitrate nitrogen exceeding 10 ppm was approximately twice as great
for applications of 100 t/ha as compared to its counterparts (Figure
22). The fact that the 100 t/ha rate treatments were not underdrained
with tile may very well account for the greater incidence of nitrate
nitrogen above 10 ppm. Lack of underdrainage on these imperfectly
drained soils may inhibit the downward movement of soluble nitrogen.
Phosphorus - Analytical determinations were made for both soluble
inorganic and total soluble phosphorus, the numerical difference being
composed of soluble organic phosphorus. Total soluble phosphorus deter-
minations were used in calculations of discharge quantities in previous
discussions. Approximately 83$ of the total soluble phosphorus was
composed of soluble inorganic phosphorus. The two are treated sep-
arately in this discussion as a matter of interest.
*
Lauer, D. A., Bouldin, D. R., and Klausner, S. D. Ammonia
Volatilization from Dairy Manure Spread on the Soil Surface.
Submitted to Journ. Envir. Qual. 19jk.
68
-------
6C
45
30
15
60
°,45
o
iu 30
o
UJ
^ 15
60
45
30
15
-
—
™~
-
-
200 t/ha
n = !38
^
100 t/ha
n=!64
35 t/ha
n=262
,
O-.l .1-1 1-10 10-100 100+
NH^-IM, ppm
Figure 20. Distribution of ammoniacal nitrogen concen-
trations in surface runoff with respect to the
rate of manure application. 1972, 1973-
69
-------
60
45
30
15
—
WINTER
n=!74
1 ,
bU
88
45
,* "TwJ
O
5 30
ID
O
UJ
U. '^
60
45
30
15
_
SPRING
n=223
-
™ *
-
-
SUMMtK
n = !67
O-.l .1-1 1-1010-100 100+
NH4+-1M, ppm
Figure 21. Distribution of ammoniacal nitrogen concentra-
tions in surface runoff with respect to timing
of manure application. 1972, 1973.
70
-------
Table 13. NITRATE NITROGEN CONCENTRATIONS IN SURFACE RUNOFF OVER A
TWO YEAR PERIOD. 1972, 1973.
Time of Rate,
applic t/ha
0"bs Mean, Standard Coeff of
ppm deviation variation,
Range
Winter
Spring
Summer
35
100
200
35
100
200
35
100
200
91
36
68
50
67
60
Uo
3.U
5-5
3A
3.7
U.7
2.5
2.2
3.6
3.2
5.6
9.1
6.2
7-3
6.7
2.2
2.5
4.2
5-2
163
183
196
1U3
90
115
117
163
.Oil. - 3^.5
.03 - 37.3
.02 - 32.5
.11 - 49.0
.02 - 32.5
.Ok - 8.7
.02 - 11A
.03 - 17.0
.25 - 30.0
71
-------
40
30
20
10
r-
200 t/ha
_
-
n= lib
! 1
T- t ' -t 1
40
30
o
o
10
40
30
20
10
100 t/ha
n*(64
35 t/ha
n*262
J
-2 2-3 3-4 4-5 5-10
IM03-N, ppm
10+
Figure 22.
Distribution of nitrate-nitrogen concentrations in
surface runoff with respect to the rate of manure
application. 1972, 1973-
72
-------
•TV
30
20
in
!U
-
WINTER
n=!74
1 1 U
40r-
30
o
u
ID
o
20
10
40
30
20
10
SPRING
n = 223
SUMMER
n = !67
0-1 1-2 2-3 3-4 4-5 5-10 10+
j-N, ppm
Figure 23. Distribution of nitrate-nitrogen concentrations
in surface runoff with respect to timing of
manure application. 1972, 1973-
73
-------
Much like ammoniacal nitrogen, both soluble inorganic and total sol-
uble phosphorus exhibited the greatest mean concentrations for the 100
and 200 t/ha manure application rates for winter disposal (Tables 14 and
15). The concentrations for the 35 t/ha winter disposal treatment were
well in line with phosphorus concentrations for the varying disposal
rates for the spring and summer applications.
The higher concentrations of phosphorus, as noted in the upper range
for the winter application, at the two higher rates of application,
were mainly associated with the single snow melt event of February
1972. Phosphorus contained in the manure applied on frozen soil did
not have sufficient retention time to interact with the soil, hence
mobility of the soluble fraction was retained.
The frequency of these outlying phosphorus concentrations (10+ ppm)
was not great (Figures 2k to 27). Over the two year measuring
period, approximately 80-90% of the occurrences were less than 1.0
ppm.
Probability - The probability of a nutrient concentration to exceed
a given value in surface runoff can be calculated from these frequency
distributions. The probability of occurrence can be determined by
the "best point estimate" and is defined as:
P [Z > Y ppm] = 1 - F [
-------
Table ik. INORGANIC PHOSPHORUS CONCENTRATIONS II SURFACE RUNOFF
OVER A TWO YEAR PERIOD. 1972, 1973.
Time of Rate, Obs Mean, Standard Coeff of
applic t/ha ppm deviation variation, % Range
Winter 35 91 0.69 1.3k 193 .01 - 9-7
100 36 2.27 5.16 227 .Ok - 22.3
200 kf 2.1k 8.62 313 .01 - 58.0
Spring 35 10^ 0.13 0.23 180 .01 - 1.8
100 68 0.22 O.fk 333 .003 - 6.0
200 50 0.96 2.18 227 -01 - 10.9
Summer 35 67 0.25 0.38 151 .02 - 2.6
100 60 0.23 0.2k 10k .01 - 1.3
200 kO Q.k3 0.55 129 .003 - 2.3
75
-------
Table 15. TOTAL SOLUBLE PHOSPHORUS CONCENTRATIONS IN SURFACE RUNOFF
OVER A TWO YEAR PERIOD. 1972, 1973
Time of
applic
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
Obs
91
36
^7
10U
68
50
67
60
Uo
Mean,
ppm
0.86
2.61
3.09
0.17
0.39
l.lk
0.3k
0.29
0.51
Standard
deviation
1.59
5-58
8.88
0.28
1.63
2.50
0.51
0.28
0.62
Coeff of
variation,
18U
2.1k
287
165
^17
219
lU9
96
122
% Range
.02
.05
.02
.02
.01
.02
.Ok
.Ok
.01
-11.0
- 23. k
- 59.3
- 2.2
- 13. 1*
- 11.7
- 3.k
- I.k
- 2.k
76
-------
60
45
30
15
60
45
30
15
200 t/ho
n=!38
FREQUENCY, %
_ CM 4* Oi
Oi O Ul O
-
V ^
100 t/ha
n= 164
,
35 t/ha
n=262
0-.05 .05-.f .1-1 I-10 10-100
INORGANIC P, ppm
Figure 2U. Distribution of inorganic phosphorus concen-
trations in surface runoff with respect to
rate of manure application. 1972, 1973-
77
-------
60,
45
30
15
60
o
w 30
O
UJ
E '5
60
45
30
15
WINTER
n=!74
SPRING
n=323
SUMMER
n = !67
0-.05.05-.I .1-1 I-10 10-100
INORGANIC P, ppm
Figure 25- Distribution of inorganic phosphorus concen-
trations in surface runoff with respect to
timing of manure application. 1972, 1973.
78
-------
60r
45
30i
15
60
45
30
15
200 t/ha
n=!38
DU
J-
O
2*
u3o
O
Ld
cr IR
u. I0
-
-
i-
i
100 t/ha
n=!64
35 t/ha
n=262
0-.05 .05-.! .1-1 I-10 10-100
TOTAL SOLUBLE P, ppm
Figure 26. Distribution of total soluble phosphorus
concentrations in surface runoff with
respect to rate of manure application.
1972, 1973.
79
-------
60
45
30
15
-
WINTER
n=!74
l
6O
a*
^45
o
y
^30
O
LJ
£ 15
75
60
30
15
-
—
-
-
1
/ /
X X
^^vn
SPRING
n=223
1
SUMMER
n-167
1
0-.05.05-.I .1-1 I-10 10-100
TOTAL SOLUBLE P, ppm
Figure 27- Distribution of total soluble phosphorus
concentrations in surface runoff with
respect to timing of manure application.
1972, 1973.
80
-------
Table 16. BEST POINT ESTIMATE OF THE PROBABILITY THAT A CONCENTRATION
OF NITROGEN OR PHOSPHORUS (z) IN SURFACE RUNOFF WILL EXCEED
Y.
Element
Y, ppm
0.5
N03-N
10.0
Inorganic-P
0.1
Total-solu-P
0.1
Time of Rate of
applicationapplic, t/ha
Winter
Spring
Summer
35
100
200
35
100
200
35
100
200
2)4
33
28
9
9
20
2k
15
8
2
111
9
7
13
3
12
5
-P[Z>Y],
6U
81
72
37
146
70
78
67
79
86
92
62
63
78
83
70
81
-------
The winter application proved to have the higher incidence of surface
runoff exceeding 0.5 ppm of NHv-N. The spring application at the two
lower rates as well as the summer application at the maximum rate
yielded the lowest probabilities of exceeding 0.5 ppm NH^-N. Plowing
down manure, as in the case of the spring application, would reduce
surface exposure of manure and lessen the probability of NH^-lf transport,
especially at the lower rates of application.
There is a consistent trend for the 100 t/ha rate of application,
regardless of the time of disposal, to exhibit a higher incidence of
surface runoff exceeding 10 ppm of NOj-N. It has been pointed
out in previous discussions that none of the plots receiving 100
t/ha are tile drained. The lack of artificial internal drainage
on these imperfectly drained soils would inhibit the downward
movement of NO^-N. Accumulations of 103-! at, or near, the
soil surface could result.
The spring plowdown of 35 and 100 t/ha, especially for inorganic-P,
displayed a marked reduction with respect to the frequency at which
runoff concentrations exceed 0.1 ppm. Similar to NH^-N, plowing
reduces surface exposure of manure and enhances soil fixation. All
other treatments showed general uniformity.
Tile effluent - Analytical determinations were made for ammoniacal
and nitrate nitrogen, soluble inorganic and total soluble phosphorus
in tile effluent. The actual nutrient concentration found in tile
effluent, as noted in the section dealing with annual nutrient dis-
charges in tile effluent, is not necessarily an ideal criteria for
determining the pollution potential of groundwater. The total amount
of nutrients delivered to a stream or lake may be more meaningful in
determining the ultimate impact of the nutrients on water quality.
The tile sampling scheme has been described previously in the
section dealing with methods and materials. Samples were taken
weekly and represent a composite of flow during that period, rather
than being specific for a precipitation event.
Ammoniacal nitrogen - Concentration of ammoniacal nitrogen in weekly
tile effluent sample showed a greater degree of variation (Table IT)
than in surface water samples (Table 12). Mean concentrations,
however, were an order of magnitude lower in the tile effluent.
Soil immobilization, nitrification and ammonia volatilization from
surface applied manure may account for this reduction.
The maximum concentrations, noted in the range, occurred very in-
frequently (3% of the time). There was general uniformity in the
frequency of NH^-H concentrations over both rates of application
and over the three times of application (Figures 28 and 29). This
82
-------
Table IT- AMMONIUM NITROGEN CONCENTRATIONS IN WEEKLY TILE EFFLUENT
SAMPLES. 1972, 1973.
Time of Rate, Mean, Standard Coeff of
applic t/ha 0"bs ppm deviation variation, % Range
Winter 35 % 0.059 0.266 1*50 .001 - 2.55
200 122 0.21*9 0.871 3l*9 .001 - 6.25
Spring 35 l6l 0.058 0.172 29** .001 - 1.1*0
200 117 0.195 0.881 1*52 .001 - 7-50
Summer 35 83 0.178 0.695 392 .001 - U.OO
200 125 O.IOU 0.561 539 -001 - 5-75
83
-------
75
60
45
30
15
o
2
LU
3
O
UJ
(E
U.
60
45
30
15
200 t/ho
n=364
35 t/ha
n = 340
O-.OI .01-.I .1-1 HO 10+
NH4-N, ppm
Figure 28. Distribution of anmoniacal nitrogen concen-
trations in tile effluent with respect to the
rate of manure application. 1972, 1973.
84
-------
60
45
30
15
60
>T 45
o
1 30
o
UJ
CE
60
45
30
15
WINTER
n = 2I8
SPRING
n«278
SUMMER
O-.OI .OKI .1-1 HO 10 +
-N, ppm
Figure 29.
Distribution of ammoniacal nitrogen concen-
trations in tile effluent with respect to
timing of manure application. 1972, 1973.
85
-------
general uniformity strongly indicates that rate and timing of
manure disposal per s_e is not influential. Soil fixation and pro-
bably nitrification and/or ammonia volatilization may be adequately
controlling NH«-N concentrations in the tile effluent in all treat-
ment s.
Nitrate nitrogen - Nitrate is highly mobile and moves readily with
water as it leaches through the soil. The lowest mean concentration
was associated with the plowing down of 35 t/ha in the spring
(Table 18). The extreme concentrations shown in the upper limit of
the range were not all a consequence of manure additions. Manure
additions began in February 1972. The starting point, as a matter
of convenience, was January 1, 1972 to enhance calendar year
accounting. The high concentrations of 62.3, 106.5 and 126.5 in
the upper range (Table 18) occurred about 2 weeks prior to the
winter application. The remaining maximum concentrations occurred
from 2 to 12 months after application. The availability of NO^-N
with time is largely a function of the rate of nitrification.
The frequency of NOo-N concentrations exceeding 10 ppm ranged from
1+5 to 70$ of the time (Figures 30 and 31). The 200 t/ha rate and
the winter and summer disposal periods approached the 70% frequency
level while the 35 t/ha rate and the spring disposal period accounted
for the k5% frequency level.
Phosphorus - Tables 19 and 20 present statistical data for soluble
inorganic and total soluble phosphorus concentrations. The mean
concentrations for the winter and spring 35 t/ha rates are much
lower than the 200 t/ha rates. Even though the soil does have a
large capacity to hold phosphorus, the higher concentrations from
the 200 t/ha rates above the 35 t/ha rates might be expected, es-
pecially when the amounts of phosphorus applied in the manure are
considered. The 35 t/ha treatments received on the average nearly
ho kg of phosphorus as soluble inorganic phosphorus in 1972 and 50
kg in 1973, whereas the 200 t/ha rates received nearly 190 kg in
1972 and 260 kg in 1973. Although phosphorus is quite effectively
adsorbed and immobilized in the soil, some phosphorus continues to
move downward with soil water. A more complete explanation of
phosphorus chemistry in the soil and how phosphorus additions in
manure affect soil solution phosphorus levels will be discussed
later in this section. Standard deviations and coefficients of
variation are high and at first glance may be distressing. This
variability simply reflects the kind of variation one encounters
under normal field and weather conditions, because of the inherent
diversity of natural systems. A look at the ranges of the values
also confirms this and helps point out why the variability was
large.
86
-------
Table 18. NITRATE NITROGEN CONCENTRATIONS IN WEEKLY TILE EFFLUENT
SAMPLES. 1972, 1973
Time of Rate, Obs. Mean, Standard Coeff of
applic t/ha ppm deviation variation, % Range
Winter 35 96 16.66 13.27 ^50 0.05 - 62.30
200 122 18.30 18.32 101 0.06 -11*7.25
Spring 35 l6l 7-07 5-62 79 0.09 - 57-25
200 117 22.1*5 23.9^ 107 0.20 -126.50
Simmer 35 83 15.85 15-3U 97 0.06 -106.50
200 125 17-^8 16.l»i 92 0.18 - 80.50
87
-------
75
60
45
30
15
85
r»
>
o
FREQUEr
-s
Ol
60
45
30
15
200 t/ha
n = 364
—
-
1 1 , • • • ,,
1 ' ' ' ' ' "TV" 7 /
35 t/ha
n*340
1 1 1 1 1 L,
-/X
0-1 1-2 2-3 3-4 4-5 5-10 10+
NOj-N, ppm
Figure 30. Distribution of nitrate-nitrogen concentrations in
tile effluent with respect to the rate of manure
application. 1972, 1973.
88
-------
60-
45-
30-
15-
o
60
45
30
o
LU
CT 15
u_
60
45
30
WINTER
n = 2!8
SPRING
SUMMER
n = 208
-^/t
0-1 1-2 2-3 3-4 4-5 ' 5-10
NO^-N, ppm
104-
Figure 31. Distribution of nitrate-nitrogen concentrations in
tile effluent with respect to the timing of manure
application. 1972, 1973.
89
-------
Table 19. INORGANIC PHOSPHORUS CONCENTRATIONS IN WEEKLY TILE EFFLUENT
SAMPLES. 1972, 1973.
Time of
applic
Winter
Spring
Summer
Table 20.
Rate,
t/ha
35
200
35
200
35
200
TOTAL
Obs
96
122
161
117
83
125
SOLUBLE
Mean,
ppm
0.009
0.188
0.009
0.115
0.0^3
0.0ll6
Standard Coeff of
deviation variation, %
0.016 183
0.639 3^0
0.019 20k
0.388 337
0.095 222
0.096 210
Range
.001 - 0.01*9
.001 - 5-220
.001 - 0.137
.001 - 3.700
.001 - 0.590
.001 - 0.6UO
PHOSPHORUS CONCENTRATIONS IN WEEKLY TILE
EFFLUENT SAMPLES. 1972, 1973.
Time of
applic
Winter
Spring
Summer
Rate,
t/ha
35
200
35
200
35
200
Obs
96
122
161
117
83
125
Mean,
ppm
0.020
0.255
0.018
0.1U9
0.058
0.065
Standard Coeff of
deviation variation,
0.026 127
0.835 327
0.027 15^
O.M*5 299
0.106 183
O.lUl 216
% Range
.001 - 0.110
.001 - 6.800
.001 - 0.202
.001 - U.100
.003 - 0.606
.001 - 1.086
90
-------
Figures 32 and 33 illustrate the frequency distributions of sol-
uble inorganic phosphorus and total soluble phosphorus concentra-
tions, respectively, for the two rates of manure application.
These figures give a clearer picture of where most of the concen-
trations fall. There is little difference between the soluble
inorganic phosphorus and total soluble phosphorus concentration
distributions within one rate, as soluble inorganic phosphorus
usually accounts for >&5% of the total soluble phosphorus. A
marked effect of treatment on concentration distributions can
be seen when the 35 and 200 t/ha rates are compared (Figure 32 and
33). The higher rate of manure shifts the frequency of concen-
trations to higher levels.
Returning to Tables 19 and 20, it will be noted that soluble in-
organic phosphorus and total soluble phosphorus mean concentration
values for the 200 t/ha summer application were much lower than for
the 200 t/ha winter and spring applications. Little difference is
apparent, however, between the effect of application time on the
distribution of tile effluent soluble inorganic phosphorus concen-
trations when averaged over both rates of application (Figure 3k).
The pattern of concentration distributions between 0 and 0.1 ppm
is very similar for all application times. The lower mean for the
summer application of 200 t/ha can be explained by the fact that
there was a smaller percentage of samples in the greater than 0.1
ppm categories for the summer than for the spring or winter appli-
cations. A few samples in the higher ranges can shift the mean
considerably higher while showing little effect on the frequency
distribution. This same pattern is also apparent for the total
soluble phosphorus (Table 20 and Figure 35).
There has been a standard belief that phosphorus is fixed within
the soil. Although true, this leads one to believe that none or
only very minute amounts of phosphorus would be expected in soil
leachates. Confusion about phosphorus availability is evident,
and a brief explanation dealing with phosphorus reactions in soil
may help clarify the problem. When phosphorus is applied to the
soil in a very soluble form such as soluble phosphorus in manure,
it immediately begins to react with the soil. Phosphorus compounds
found in soil are very insoluble and the chemistry of phosphorus
is such that it does not remain in solution at high concentrations
for very long. The chemistry of the inorganic phosphate ion,
H9POk- or HPOf; is completely different than that of a soluble ion
such as nitrate (NOo). Phosphate can truly be considered a very
slightly soluble ion in a soil system. In the absence of plants,
phosphorus concentrations in soil solution may be reduced_by two
processes. The first is adsorption of the phosphate by minerals
or clays in the soil. The second is by precipitation of very
91
-------
100
80
60
40
20
o
z
UJ
oioo
UJ
cr
^80
60
40
"55 t/ha
n = 338
200 t/ha
*
0*
o*
Figure 32.
INORGANIC-P, ppm
Distribution of inorganic phosphorus concen-
trations in tile effluent with respect to the
rate of manure application. 1972, 1973.
92
-------
100
80
60
40
20
o
UJ
0100
UJ
IT
U_
80
60
40
20
35 t/ha
200 t/ha
—
0*
0»
ofe
I
1 l_
d* x>° ' '
«P
i i
N? v*
Figure 33.
u Ou O Cr 9 > •
TOTAL SOLUBLE-P, ppm
Distribution of total soluble phosphorus concen-
trations in tile effluent with respect to the rate
of manure application. 1972, 1973-
93
-------
80
60
40
20
80
FREQUENCY, °/<
ro 4* 0>
O O o
80
60
40
20
-
-
-
-
-
#
_/ •
WINTER
n = 2!6
— , , .,| 1
SPRING
n=276
1 i j — j ^
SUMMER
n = 207
I ( ^ J | t
pjX r& (A vP " ..P V X
V V O ^ >
-------
80
60
40
2O
fnm\^/
80
85 60
X-
S~
£ 40
LU
Z>
O
1 1 1 ns\
LU gO
U-
-
WINTER
n=2!6
-
— Y /*"— • — ; « J
SPRING
n = 276
w
1 \f \ "1
80
60
40
2O
£m\J
-
SUMMER
n= 207
s •
& & 0* A° ' ' fP ^ S
t. s- f. *if s •
-------
insoluble phosphorus compounds. In the case of the high lime soil
in this experiment, phosphorus is precipitated as calcium phosphate.
The sorption reaction is quite rapid, occurring within minutes and
continuing for several days. The precipitation reaction is much
slower, occurring within hours, and proceeding for years.
Possible reactions of soil solution phosphorus are shown in Figure
36. Phosphorus in soil solution may be present in either inorganic
or soluble organic compounds. The organic phase can be mineralized
to inorganic phosphorus by soil microbial activity or some inorganic
phosphorus may be utilized by microbes for growth and incorporated
into organic phosphorus. Adsorbed phosphorus may slowly be changed
to slightly soluble phosphorus compounds but the exact mechanisms
of this change are not well understood.
One of the characteristics of a soil is its phosphorus sorption
capacity which can be determined in the laboratory. The value
gives some idea of how much phosphorus a soil can adsorb. Some
representative values for the soil of this experiment are in the
range of 300 to 350 mg P adsorbed for each kg of soil.
A hectare of land to a depth of 30 cm could adsorb between 1200-
1^00 kg phosphorus. In light of the amounts of phosphorus applied
in manure (see Tables A9, A10 Appendix) after two years, the soil is
still well below its phosphorus sorption capacity, but still there
had been an increase in the tile effluent phosphorus concentrations.
Soil solution levels of phosphorus can change even though enough
phosphorus has not been added to satisfy the sorption capacity of the
soil. In a previously unfertilized soil, phosphorus concentrations
in soil solution may be in the range of 0.005 to 0.010 ppm as sol-
uble inorganic phosphorus. The concentration found in soil solution
is often referred to as the Intensity Factor for soil solution phos-
phorus. If soil solution concentrations of phosphorus fall due to
plant uptake, phosphorus will be released from the adsorbed phase
and possibly some from the slowly soluble phosphorus compounds to
maintain the phosphorus concentration. This aspect of replenish-
ment is referred to as the Capacity Factor. When phosphorus is
added to soil from manure, soil solution levels of phosphorus in-
crease rapidly but then soon begin to decrease due to adsorption
and precipitation reactions. Intensity (soil solution phosphorus
concentration) increases then decreases; capacity slowly increases
with additions of phosphorus to the soil.
The new phosphorus concentration levels in soil solution after a
manure addition will be higher than previous levels. If this new
higher level of phosphorus is depleted by plant growth, the capacity
factor will replenish soil solution phosphorus levels to its previous
level.
96
-------
SOIL SOLUTION
ORGANIC PHOSPHORUS
SOIL SOLUTION
INORGANIC
PHOSPHORUS
ADSORBED
PHOSPHORUS
CRYSTALLINE //
PHOSPHORUS ^
COMPOUNDS
Figure 36. Phosphorus reactions in soil solution.
97
-------
Phosphorus in solution can move downward through the soil and, in the
case of tile drained soils, eventually reach the tile. The subsoil
also has a high phosphorus sorption capacity but usually has a very
low phosphorus capacity factor. This means that high phosphorus con-
centrations in soil solution moving down from the plow layer will be
"scrubbed" of phosphorus by the adsorption processes in the subsoil.
After manure application, tile flow from a manured field may show
little or no increase in soluble phosphorus concentration. As more
and more phosphorus moves into the subsoil, the intensity and capa-
city of the subsoil are also increased. After this time, an increase
in tile effluent phosphorus concentrations may be noted. Soil water
which was not intercepted by the tile and continued to move deeper
into the soil would lose phosphorus by soil sorption or precipita-
tion, so water reaching lower levels would have lower phosphorus
concentrations. From this discussion, it can be seen why adding
large amounts of phosphorus in manure eventually has an effect on
tile effluent phosphorus concentrations. It should also point out
why concentrations found in tile effluent are probably not repre-
sentative of phosphorus concentrations found in ground water.
Probability - The probability of a nutrient concentration in tile
effluent exceeding a given value can be calculated from the frequency
distribution. The probability of occurrence can be determined by
the "best point estimate." The procedure has been discussed in this
section dealing with surface runoff nutrient concentrations.
The best point estimate of the probability of nitrogen and phos-
phorus exceeding a given concentration in the tile effluent is
presented in Table 21. In general, there is a relatively low pro-
bability of tile effluent exceeding 0.5 ppm NBY-W, but a very
high probability of exceeding 10 ppm of NOo-N. The major dif-
ference being a greater mobility of nitrate in comparison to
ammonium and the shift of nitrogen to the oxidized form in an aerobic
system.
The probability of phosphorus concentrations exceeding 0.1 ppm
is very minute for the lower rate of application during the winter
and spring dispoasl periods. Differences in probability estimates
based on rate for the summer disposal period are essentially non-
existent .
Reference to Table 16 clearly demonstrates that surface waters
have a greater tendency to yield higher concentrations of WH,-H
and lower concentrations of NOo-H than does tile effluent. The
probability of phosphorus concentrations exceeding 0.1 ppm are
far greater in surface runoff in contrast to tile effluent.
98
-------
Table 21. BEST POINT ESTIMATE OF THE PROBABILITY THAT A CONCENTRATION
OF NITROGEN OR PHOSPHORUS (Z) IN TILE EFFLUENT WILL EXCEED
Y.
Element NH^-N NOo-N Inorganic-P Total solu-P
Y, ppm 0.5 10 0.1 0.1
Time of Rate of
application applic, t/ha P [Z>Y],
Winter 35 1 6U <1 2
200 8 69 22 32
Spring 35 3 18 1 1
200 ^ 82 18 21
Summer 35 5 69 12 13
200 3 63 9 1^
99
-------
Rainfall Simulation -
An irrigation experiment was initiated to study the movement of
soluble nitrogen and phosphorus with time during a runoff event.
With this situation, a calculation of discharge rates of nitrogen
and phosphorus with time could be determined. In addition to loading
rate calculations, it was of interest to record the concentration of
nitrogen and phosphorus in surface runoff and tile effluent with time
during a single drainage event.
An estimate of the maximum amount of nutrient loss that can be
expected after manure remained on the soil surface for a period of
time was desired. A demonstration plot which received 200 metric
tons/ha of manure on June 12 was selected. The irrigation experiment
started on October 29, 1973. During the intermediate months, 20 cm
of rainfall occurred (9-3 cm below average) and less than 0.02 cm of
runoff was produced from this plot. Water was applied to the 0.32 ha
plot by sprinkler irrigation at the rate ranging from 6 to 11 cm/hr
during a two day period to bring the soil to saturation. The follow-
ing morning, irrigation water was applied at a constant rate of 6
cm/hr for an additional k.5 hours to produce runoff and tile dis-
charge .
Water samples were collected to correspond to various segments on
the hydrograph for both surface runoff and tile discharge. Surface
runoff continued for 26 hours and tile flow continued over the next
several weeks, compounded by additional rainfall at later dates.
Water samples were analyzed for nitrogen and phosphorus as- described
in the section on Methods and Materials.
A total of 16.k cm (530 m^) had been applied over the three day
period. Surface runoff and tile discharge occurred after 13-5 cm
(1*36 m-3) and 10 cm (321 up) of water were applied respectively.
Surface runoff - The volume of runoff in addition to the concentration
of nitrogen and phosphorus is presented in Figure 37. It is evident
that the nutrient concentrations did not vary greatly with the volume
of discharge water and a nearly constant concentration was main-
tained. Nutrient concentration began to drop markedly only as the
cessation of flow was approached. By 1000 hours on the second day
of runoff, there was no longer any water moving across the surface
of the soil. The last h hours of flow was "tail flow" in which
laterally moving subsurface water, at a shallow depth, was being
intercepted by the drainage ditch and diverted to the recording
flume. Concentrations of nitrogen and phosphorus in this subsurface
water were somewhat lower than in the water moving across the surface.
100
-------
.35
HOUR
Figure 37- Concentration of nitrogen and total soluble phosphorus during a surface
event.
runoff
-------
The concentration of NOg-N ranged from 11-19 ppm throughout the
runoff event with a mean value of l6 ppm for the event. Using less
than 10 ppm as a guide for acceptable water quality for potable
water (l8), nitrogen concentration being discharged during this
runoff event were above acceptable limits. Total soluble phosphorus
concentrations ranged between 1-k ppm with a mean value of 3.1 ppm.
To date, a maximum phosphorus concentration for potable water has
not been established.
Extreme care should be used when interpreting these concentrations in
runoff water for several reasons. First, these nutrient losses are
considered to be an overestimate of what actually occurs in a water-
shed. Manure was spread from adjacent to to a maximum of 60 meters
from the interceptor ditch which diverts water to the sampling device.
In actual practice, this would be analagous with spreading manure
adjacent to a stream bank. Secondly, the behavior of nitrogen and
phosphorus in transport from a disposal field to a well defined
watercourse is not well understood. Nutrient loading to a water-
course would depend on length of travel, additional diluting water,
topography, soils, vegetation, etc. Thirdly, loading rates approach-
ing 200 metric tons/ha over extensive areas is not a common occurrance.
The data presented, however, become extremely important when study-
ing the behavior of nitrogen and phosphorus losses from a well
defined disposal field. Extrapolation of nutrient loadings from a
segment of a watershed to a stream or lake should be done with caution.
The discharge rates of inorganic nitrogen (BFOo-1 + IH^-l) and
total soluble phosphorus for this runoff event are illustrated in
Figure 38. Since the quantity of discharge is directly proportional
to the flow and the concentration of nitrogen and phosphorus are
relatively constant, a linear response is achieved. Correlation
coefficients for flow vs nutrient discharge for nitrogen and phos-
phorus were 0.99 and 0.98 respectively.
The loss of inorganic nitrogen in surface water for the entire run-
off event was 3.9 kg/ha. Approximately 1.0$ of the inorganic
nitrogen was as ammonium nitrogen, the remaining as nitrate nitrogen.
The total soluble phosphorus loss during the same event was 0.8 kg/ha
with 90$ being soluble inorganic and the remainder as soluble organic
phosphorus.
Tile drainage - Tile flow began on October 30 after 10.2 cm of water
had been applied. Irrigation ceased at ikOO hours and continued the
next morning on October 31. Water samples of tile flow were taken
on the concentration and recession limbs of the tile discharge hydro-
graph to determine nutrient concentrations as affected by flow.
Samples were analyzed for ammonium-N, nitrate-N, soluble inorganic
phosphorus and total soluble phosphorus.
102
-------
o
oo
W280
E
o
iy
tt200
-------
Nitrate concentrations in tile effluent showed an expected inverse
relationship with flow (Fig. 39 and ko). Ammonium-N concentrations
are all less than 0.30 ppm and contribute_very little to nitrogen
loss from tile effluent.
Concentrations of soluble inorganic phosphorus gave a surprising
result. Concentration increased as flow increased then diminished
as flow decreased (Fig. 39 and ho). This was rather unexpected
because phosphorus in soil solution is controlled either by adsorbed
phosphorus or slowly soluble crystalline phosphorus compounds,
neither of which should account for this increase in concentration
with flow. The irrigation water contained only 5 ppb inorganic
phosphorus so this could not explain the result. Chemical reduction
of the soil matrix cannot explain this result because there would
not be sufficient time or water saturation for the process to occur.
More than just the soil chemistry of phosphorus was evidently involved
here.
After further study, the answer seemed to be involved with the water
movement in the soil to the tile. As tile flow began, the water was
primarily from soil solution displaced from soil just above the tile.
Flow increases resulted from water moving downward through the plow
layer which can maintain a high phosphorus concentration. As more
water was applied, the plow layer reached saturation due to the
slowly permeable underlying firm till. Water then began to move
laterally downslope on the firm till plow layer interface toward the
tile. This water that reached the tile also had a high phosphorus
concentration and for this reason high phosphorus concentrations
resulted at high flow. Some water did enter the firm till and moved
slowly toward the tile. When precipitation or irrigation stopped,
flow began decreasing but phosphorus concentrations did not drop
immediately due to the large component of flow from the plow layer.
As flow continued to drop, more of the total flow was from soil
solution moving laterally downslope and moving out of the firm till.
The low phosphorus concentration solution from the till diluted the
higher phosphorus concentration flow from the plow layer and phos-
phorus concentration then continued to decrease as flow declined.
As the soil slowly drained, soil adsorption of phosphorus helped
decrease the phosphorus concentration in soil solution which eventually
reached the tile. Finally, at low flow only, soil water from the
firm till comprised flow and phosphorus concentration dropped to
levels near 30-50 ppb P.
Nitrate-N concentrations in tile flow ranged between 22-73 ppm. This
is well above the 10 ppm Public Health Standard (l8). Nitrate-N loss
per day during the time which the tile was flowing is shown in Table
22. Nitrogen loss is related to flow hence most of the loss occurs
at peak flows. The loss of soluble nitrogen can be described as a
104
-------
O
to*
E
0.08 3
u.
UJ
0.02
13
14 15
16
17
18 19
20 21
HOUR
22 23 24 05 06 O7
Figure 39. Concentration of nitrate-nitrogen and inorganic phosporus in tile flow.
October 30-31, 1973-
-------
o
OTA
Q.
O.
I
ro
O
70
60
50
40
30
20
10
1.2
1.0-
£
Q.
Q.
h 0.8
u 0.6
- 0.4
- 0.2
IM03-N
FLOW
08 09 10 II 12 13 14 15 16 17
HOUR
18 10 II 12 13
O.I 2 -
10
0.10 E
0.08°
u.
UJ
0.04
0.02
Figure 40. Concentration of nitrate-nitrogen and soluble inorganic phosphorus in tile flow.
October 31 - November 1, 1973.
-------
Table 22. NUTRIENT LOSSES FROM TILE FLOW DURING A DRAINAGE EVENT.
Nitrate-nitrogen Phosphorus
October 30
October 31
November 1
2
3
h
5
6
Total
735
1^72
538
198
16U
87
^8
28
3270
11
>+5
2
0
0
0
<0
<0
60
-7
.3
.5
.U
.2
.1
.1
.1
.3
107
-------
simple function of flow for a given event. Because of leaching of
nitrate-N from soil with continued events, the equation for nitrate-
N discharge rate as a function of flow would change (Fig. Ul). To
obtain a more valid estimate of loading that may reflect seasonal
variations, more work of this type throughout the year would be
required.
Ammonium-N losses were very low. Ammonium is a cation in soil solu-
tion and is easily retained by the exchange complex of the soil,
hence low concentrations remain in soil solution resulting in
minimal losses.
Phosphorus concentration ranged much less than that found in the
surface runoff which indicated that the soil is retaining phos-
phorus from the manure.
Phosphorus discharge for this experiment is shown in Fig. \2. The
loading rate is a function of flow, but it is not a simple linear
function. The equation which best describes the data is a quadratic.
This is not unexpected since we note high concentrations at high
flows so most of the loss will be at these values. It can be seen
from this figure that at very low flows this equation predicts nega-
tive phosphorus loss. This is a limitation of the equation because
as long as there is any measurable phosphorus concentration and flow,
there will be phosphorus loss. Further work should be done to as-
certain seasonal patterns because extension of this model beyond this
data is uncertain without further verification.
In summary, it can be concluded that phosphorus losses from the tile
will generally be quite small because of the soil's inherent ability
to retain phosphorus. Nitrogen losses will always be higher due to
the movement of soluble nitrate. Interpretation of concentration
must be approached cautiously. Nutrient losses and concentrations
must be viewed with respect to the impact they have on the streams
within the watershed and not simply by themselves. Soluble inorganic
phosphorus and nitrate concentrations in tile effluent also probably
do not represent concentrations that would be found in soil solution
which continues to seep downward through the soil into groundwater.
Phosphorus concentrations would be reduced greatly due to the high
phosphorus fixing capacity of subsoils and nitrate could be lost
due to denitrification. Data obtained from this type of experiment,
however, does provide pertinent information on nutrient losses dis-
charged in a single drain tile from a specific event.
Soil Retention
Soil retention for the purpose of this report can be defined as the
108
-------
200 - A
CO
6
2 160
o>
CD
or
-------
CO
E
o
w
O>
8
LJ
CD
I
o
-6
Q D
O)
ID
-------
ability of the soil matrix to retain the nutrients added in animal
wastes. It could be thought of as being synonymous with the efficiency
at which a sewage treatment plant is operating from the standpoint of
nutrient removals. In the case of soils, the concept of nutrient
removal per se is not valid. Such a concept must be thought of as
the ratio of the input of an element to its outflow into the environ-
ment. The quantity of material retained by the soil in a given period
of time may still be subject to removal in the future by a crop, by
water, or by chemical and biological transformations.
The retaining ability of a given soil was measured as it was influenced
by the rate and timing of dairy manure disposal. The retention effi-
ciency of nitrogen and phosphorus is expressed as:
RE = (input-output)/input
The inputs of nitrogen and phosphorus were determined from manure
loadings based on dry matter contents and nutrient concentrations
(Tables AT-A10, Appendix). Outputs were calculated from nutrient
losses in both surface water and sediment, and include soluble
nitrogen and phosphorus in the solution phase and total nitrogen and
phosphorus in the solid phase, over a two year period (1972, 1973).
The inclusion of deep seepage outflows was ignored for the purpose
of these calculations because chemical and biological transforma-
tions (eg, denitrification, additional phosphorus fixation) in the
deeper soil profile were not measured. In addition, the 100 t/ha rate
of application was not tile drained, making relative comparisons
difficult.
Table 23 presents the percent of nitrogen and phosphorus retained by
the soil over a two year period of manure inputs. The soil system
in itself appeared to be an excellent disposal medium for dairy
manure. The retaining efficiencies ranged from 89-2 to 98-7% for
the imposed treatments. The lowest efficiency rating appeared for
the winter applied 100 t/ha treatment (89-2$). The reason for the
lower retention was due primarily to the disposal of this treatment
on dense melting snow over frozen soil in 1972 which resulted in
excessive losses in runoff.
In general terms, Table 23 denotes that the winter application had
a somewhat lower retention efficiency than the spring and summer
applications for both nitrogen and phosphorus. Efficiencies for the
loading rate are fairly comparable. The higher loading rate (200
t/ha) had the greatest value because it had the largest input of
nitrogen and phosphorus. Soil management practice has repeatedly
shown an influence on nutrient discharges. A well managed soil
in terms of past reincorporation of plant residue, hence improved
111
-------
Table 23. RETENTION EFFICIENCY OF THE SOIL BASED ON NUTRIENT INPUTS
FROM MANURE AND DISCHARGES IN SURFACE RUNOFF AND SEDIMENT.
SUM OF 1972 AND 1973-
Time of Rate, Nitrogen, kg/ha Retention,
applic. t/ha In Out %
Winter 35 308
100 866
200 1631
Spring 35 359
100 1061
200 1851
Summer 35 356
100 10714.
200 217^
Time
Rate
Soil m'gt
13
9^
2k
12
26
5U
IT
111
23
Winter
Spring
Summer
35
100
200
Good
Poor
95.8
89.2
98.6
96.7
97. 5
97-1
95.3
96.2
98.1
MEANS
95-^
97-1
97-5
95-9
9U.6
98.2
97-9
95-7
Phosphorus ,kg/ha
In Out
85
221
388
78
218
1+33
90
263
5U5
h
22
10
3
5
22
1*
12
7
Retention,
%
95.3
89^9
97. U
95-9
97-5
95.0
95.6
95-3
98.7
9*K 8
95.8
97.3
95-7
9U.2
97.2
97.8
9U.U
112
-------
soil structure, has shown to be a superior disposal medium than a
poorly managed soil.
Soil and Crop Response
Soil Analysis -
A soil sampling program was initiated to determine the influence of
dairy manure additions on the nitrogen, phosphorus and organic matter
reserve in the soil. Initial soil samples were collected from each
experimental plot in the summer of 1971. This was six months prior to
the first manure addition. Soil samples were again collected during
the summer of 191k, nearly two months after the last addition of
manure. Samples were taken from the plow layer (0-25 cm) and
analyzed for total-N, available-P and organic matter.
Table 2k presents the 1971 and 197^ soil analysis as well as the
changes occurring over the three year period. The values in Table
2k are expressed as percentages. The only significant increase
from 1971 to 197^ was for available soil phosphorus at the highest
rate of manure application. Although there appeared to be an
appreciable increase in total soil nitrogen at the 200 t/ha rate of
application, the increase was not statistically different because
of inherent variability.
The soil in itself contains a large pool of nitrogen, phosphorus and
organic matter. At concentrations of 0.19, .0011 and 3-71 percent,
the initial soil quantities of nitrogen, available phosphorus, and
organic matter were 6^00, 37, and 125,000 kg/ha, respectively. Avail-
able phosphorus (not total phosphorus) has a much lower soil reserve
because of phosphorus fixation. At such high initial soil contents,
it would take tremendous inputs from dairy manure to consistently
raise these contents significantly over a three year period.
The smallest increase in soil concentration of these three con-
stituents was noted for the 35 t/ha rate of application. A study of
the individual plots receiving this rate of application showed^that
in 33% of the cases, there was an actual decline in concentration
of total soil nitrogen. For the 35 t/ha application rate the decline
in available phosphorus and organic matter occurred in k2 and 33$
of the cases, respectively. Since almost one-half of the 35 t/ha
treatments showed a negative balance with respect to available phos-
phorus, the overall average for this rate of application also showed
a slightly negative increase (Table 2k). It is postulated, that
after a period of successive inputs, equilibrium will become estab-
lished, and a positive increase will result.
113
-------
Table 2k. SOIL ANALYSIS OF THE PLOW LAYER (0-25 CM) AS INFLUENCED BY ADDITIONS OF DAIRY MANURE FOR
THREE CONSECUTIVE YEARS. VALUES EXPRESSED AS PERCENT.a'b
Treatment
Time of
applic
Winter
Spring
Summer
Rate, t/ha
35
100
200
Soil mg't
Good
Poor
Average
Total-N
1971
0.196
0.182
0.193
0.189
0.189
0.19U
0.193
0.188
0.190
0
0
0
0
0
0
0
0
0
197^
.209
.191
.202
.193
.195
.222
.20^
.197
.201
Available-P, x 10~3
Gain, % 1971 197^ Gain, %
6.6 a 1
IK 9 a 1
IK 7 a 1
2.1 a 1
3.2 a 1
1*4.1* a 1
5.7 a 1
U. 8 a 1
5.8 a 1
.05
.18
.11
.11
.02
.20
.02
.21
.11
1.52
1.78
1.08
1.60
3.25
1.78
1.72
1.75
UU.8 a
50.8 a
7U.8 a
-2.8 a
56.9 a
170.8 b
7U.5 a
ij-2.1 a
57-6 ab
Organic matter,
1971 197^
3-90
3.50
3.75
3.66
3.80
3.73
3.77
3.66
3.71
U.05
3-70
IK 01
3.67
IK 01
U.OO
3.8U
3.92
at
1°
Gain, %
3.8
5-7
6.9
0.0
5-5
15.8
6.1
5-7
a
a
a.
a
a
a
a
a
a
a Percentages followed by the letter show a non-significant increase from 1971 to 197^ at 5% level,
b ,
To convert to kg/ha multiply by 3-36 x 10
-------
The mineralization (conversion of organic to inorganic) of organic
nitrogen from manure has always been of interest because of its
potential soil fertility value. Table 25 shows that the average
increase of organic nitrogen in the soil over a three year period
was 35%. Based on this average increase, Bouldin* determined the
decay series of organic nitrogen over the three year period. The
calculated decay series was .55-.30-.l6. That is, 55$ of the
organic nitrogen in the first year is mineralized. The second
year, 55% of the organic nitrogen is mineralized from the current
input, plus 30% of the residual from the first year. The calcu-
lation for the third year manure input is 55% of the current year,
30% of the residual from the second year and 16% of the residual
from the first year.
Actual calculations showed the decay series to be a reasonable
estimate of the increase in organic nitrogen in the soil after three
successive years of dairy manure applications (Table 26). This
type of calculation is advantageous in determining how much of the
organic nitrogen present in manure will become available for plant
growth or as potential soluble nitrogen subject to water transport.
Calculations of the mineralization of organic phosphorus as a means
of estimating available phosphorus is much more complex. This is
due to the fact that available phosphorus can be rendered unavailable
because of soil fixation.
Crop Response -
In any land disposal scheme, the response of a growing crop to the
addition of dairy manure is very important. Manure management schemes
which are detrimental to crop production will never become an accep-
table practice in a farming situation.
Corn yields were obtained from each experimental plot for 1972 and
1973. Corn harvesting for 197^ had not been completed at this
writing. Yields for both grain and silage are presented in Table •
27-
Grain and silage yields did not respond significantly to the timing
of manure application (Table 27). It is well understood that maximum
yield response is approached when sufficient nitrogen is applied just
prior to the maximum demand of the crop. Application of nitrogen
made far in advance of crop demand is subject to losses. The reason
for the non-significant crop response to additions of manure varying
from winter to summer applications may have been due to the loss of
* Bouldin, D. R. Personal communication, Cornell University.
115
-------
Table 25. MASS BALANCE OP ORGANIC NITROGEN FROM DAIRY MANURE AS A PERCENT OP THREE SUCCESSIVE
YEARLY INPUTS.
Rate,
t/ha
35
100
200
Average
Total-N, %
1971 197^
.189
.189
.191
.193
.195
.222
.203
Increase, Input of organic-N, from manure
kg/ha at 70$ of Total-N, kg/ha a
135
200
950
UU8
335
1000
2000
1111
Increase of organic-N
as % of 3 year input
20
H7
35
£ Approximately 30% of the total nitrogen was inorganic nitrogen.
OJ
Table 26. CALCULATION OF DECAY SERIES FOR EACH 100 KILOGRAMS OF ORGANIC NITROGEN FOR A THREE
YEAR PERIOD.
Manure added Amount decomposed, kg Residual at end, kg
in 1972 1973 197*4 1972 1973 197^
1972 55 ^ 5 U5 31 26
1973 55 lU - U5 31
197^ - 55 - 1*5
Total 55 69 7^ ^5 76 102
% Remaining after 3 years = 102/300 =
-------
Table 27. COM RESPONSE TO ADDITIONS OF DAIRY MAMJRE.a
Treatment
Time of
application
Winter
Spring
Summer
Rate, t/ha
35
100
200
Soil mg't
Good
Poor
Average
Grain, kg/ha
1972 1973
3575
3763
hoik
2885
i*oii*
5331
1*328
3261
3763 a
1*077
1*516
1*516
3700
l*70l*
5331
1*579
1*11*0
1*390 b
Avg.
3826 a
l*ll*0 a
1*265 a
3293 a
1*359 b
5331 c
l*l*5l* a
3700 b
1*076
Silage, t/ha
1972 1973 Avg.
22.0
23.7
25-3
19-6
21*. 6
31.0
25-7
21.7
23.7 a
29.3
29.8
30.2
27.1
31.5
33.6
30.8
28.8
29. 8b
25.6 a
26.8 a
27.8 a
23.1* a
28.0 b
32.3 c
28.2 a
25.2 b
26.7
a Means followed by the same letter are not statistically different
@ 5% level.
117
-------
inorganic nitrogen (almost entirely as NH_) by volatization before
soil incorporation. If the manure had been plowed down within hours
after the spring application or injected into the soil for the summer
application, an additional crop response to nitrogen may have occurred.
Immediate soil incorporation far in advance of the growing season
(winter and pre-winter applications) would still be disadvantageous
because of nitrification. The soluble nitrogen would then be sub-
ject to loss by runoff or leaching.
Corn response to the rate of application proved to be significant
(Table 27). Increasing rates of manure significantly increased the
yields of both grain and silage. Soils that were well managed pro-
duced higher yields than poorly managed soils because of a more
favorable plant environment.
The response of corn was very well correlated with the amount of
nitrogen and phosphorus taken up by the plant (r = = 92 and .87
respectively). Plant uptake is noted in Table 28.
Additional calculations (presented in Tables 29 and 30) were made
to determine the percent recovery of nitrogen by corn at each of the
three rates of application. Calculations of recovery efficiencies
from manure nitrogen alone is impossible owing to the fact that
nitrogen is also supplied by rainfall, decomposition of organic matter,
etc. and these sources cannot be segregated in the total plant uptake.
The amount of nitrogen made available by the mineralization of organic
nitrogen in manure is presented in Table 29 based on the determina-
tions in Table 26. The available nitrogen for crop uptake in
Table 30 includes that portion that has been mineralized from manure
plus the additional input of 105 kg/ha as noted in the footnote of
this table.
The percent recovery of available nitrogen by the corn crop (Table 30)
did not differ greatly between the two years but did drop markedly
as the rate of application increased. Obviously, the efficiency of
utilization of nitrogen decreases with increasing surpluses of avail-
able nitrogen. Rates of 100 and 200 t/ha of manure are in excess of
the needs for nitrogen by corn. A rate of 35 t/ha in combination
with a modest amount of mineral fertilizer (efficiently timed and
placed in the soil) could very well result in yields comparable to
200 t/ha of manure. With an increase in yield at the 35 t/ha rate,
recovery percentages could be higher since nitrogen uptake for the
total crop would increase at a faster rate than the increase in
added available nitrogen from fertilizer. Additional data con-
cerning itself with rates of application combined factorially with
rates of mineral fertilizer is necessary to achieve conclusive
118
-------
Table 28. NITROGEN AND PHOSPHORUS UPTAKE BY CORN.1
Treatment
Time of
application
Winter
Spring
Summer
Rate, t/ha
35
100
200
Soil mg't
Good
Poor
Average
Total-N, kg/ha
1972 1973 Avg.
8^ 97
9k 105
105 112
73 8k
105 113
125 139
101 112
88 99
9k a 105 b
90 a
100 a
108 a
78 a
109 b
132 c
106 a
9k b
100
Total -P, kg/ha
1972 1973 Avg.
16
19
18
15
18
22
19
16
18 a
18
21
19
17
21
20
19
19 b
17 a
20 a
18 a
16 a
20 ab
23 b
20 a
18 a
19
a Means followed by the same letter are not statistically different
@ 5% level.
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Table 29- INPUT AND AVAILABILITY OF ORGANIC NITROGEN FOR THREE RATES
OF MANURE APPLICATION.
Rate, Input, kg/ha Mineralized organic-N, kg/ha
t/ha 1972 1973 1972 1973
35 111 111 6l 77
100 333 333 183 230
200 666 666 366
Table 30. PERCENT RECOVERY OF AVAILABLE NITROGEN BY CORN FOR THREE
RATES OF MANURE APPLICATION.
Q
Rate, Available, Uptake, Recovery, Available, Uptake, Recovery,
t/ha kg/ha kg/ha % kg/ha kg/ha $
I-? \<- ...... , .±y | 3
35
100
200
166
288
1*71
73
105
125
kk
36
27
182
335
565
8k
113
139
1*6
3k
25
Q
Additional inputs of available -N in kg/ha = 17 in fertilizer + 11 in
rainfall + 10 nonsymbiotic fixation + 67 from soil organic matter =
105 kg/ha. This is in addition to the quantity mineralized in Table
29-
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evidence as to the most desirable combination for efficient crop
production. Maximizing efficient utilization of plant nutrients
automatically minimizes nutrient losses to the environment.
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SECTION IV
GUIDELINES FOR LAND APPLICATION OF MANURE
FUNDAMENTALS
General
Land represents not only an appropriate disposal medium for
manure but also an opportunity to manage wastes with mini-
mum adverse environmental effects. Chemical, physical and
biological properties of the soil should be utilized as an
acceptor for residues with minimum unwanted effects to the
crops that are to be grown, as well as to characteristics of
the soil and to the quality of the ground water and surface
runoff.
The soil system is a complex of chemical, physical and
biological properties. Such properties determine, to a
large extent the suitability of the soil for growing plants.
They also determine suitability for manure disposal. Con-
siderations such as topography and climate may determine the
practicability or the extent to which any particular soil can
be utilized. Soil properties that are important for growing
plants determine the fate of waste materials applied to or
incorporated in the soil. Since there are many soil types,
varying in characteristics, a knowledge of some of these
more important characteristics will permit a more judicious
use of the soil. Soils will continue to be used as a 'sink'
for waste disposal and knowledge of soil properties can be
used to establish safe loading limits of the soil. Un-
necessary pollution of groundwater, streams and lakes can
occur because soil properties are not known or understood.
Soils vary greatly in their physical and chemical properties.
They are classified according to these properties. By know-
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ing some important properties of the soils in question, they
can be grouped into a few meaningful categories. These pro-
vide a valuable guide for waste disposal purposes. Such
information is contained in soil survey reports. The layman
may find the advise of a soil scientist to be valuable when
attempting interpretation of such soil survey reports. These
soil survey reports can usually be obtained locally through
the county Agricultural Agent or the local soil conservation
district office. Frequently, these local offices are com-
bined with the local office of the U.S. Soil Conservation
Service. Complete soil survey reports may also be purchased
from the Superintendant of Documents, Government Printing
Office, Washington, B.C. Frequently, individual copies for
specific counties can be obtained free of charge from the State
College of Agriculture or the office of the local Congressman.
Soil Chemical Properties
Soils of the humid temperate regions have a net negative
charge which permits the soils to retain or hold the posi-
tively charged ions, thus providing a reservoir or storehouse
for plant nutrients. The extent of this ability to hold
cations is termed the cation exchange capacity. Cations are
held by this exchange complex. Common cations held in this
manner are calcium, magnesium, potassium, ammonium, sodium,
and aluminum. The source of these cations can be any one or
a combination of the following: the results of mineral
weathering, organic matter decomposition, applied manure,
or fertilizer.
Negatively charged anions such as nitrate are not affected by
the temperate region soil charges and move freely with soil
water. Nitrates moving beyond the rooting depth of crops
or across the soil surface can affect water quality. Nitro-
gen and phosphorus will be emphasized in this discussion
because they are considered to be major sources of potential
water quality problems. They are found in large quantities in
animal wastes.
Soil Physical Properties
The physical properties of the soil determine the rate at which
water moves into (infiltration) and through the soil (leaching or
percolation). Soil texture and structure determine these rates.
Texture refers to size groupings of individual particles such as
sand, silt and clay. Structure refers to the grouping of the
individual particles into aggregates. These factors determine
123
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the porosity or pore size distribution in soils vhich is im-
portant to the transmission rate of water through the soil. The
movement of soluble nutrients such as nitrate nitrogen occurs
more readily in sandy soils than in silt and clay soils because
the water holding capacity is greatest for clay soils, less for
silts and least for sands.
Other physical properties of importance when considering land
for waste disposal include location of dense subsurface layers,
seasonal water tables, topography, and degree of natural and
artificial drainage. Anything that restricts downward water
movement and causes oversaturation of the surface soil can
result in excessive surface runoff. Adequate infiltration of water
and sufficient soil aeration are essential for crop growth
and microbial activity for the breakdown of animal wastes.
Nitrogen and Phosphorus
A major portion of the nitrogen in manure reaches the soil in
the organic and ammonium forms. By microbial activity, the
organic forms are converted to the ammonium form. Ammonium
ions (NH^) can be absorbed on the exchange sites (cation exchange)
of the soil. Hence, their mobility is reduced. Ammonium ions
are also subject to nitrification. The usual end product is
nitrate (NOo) which is soluble and mobile. Nitrate is easily
lost by runoff or by leaching to the deeper depths of the soil.
At these deeper zones of the soil profile, some of the nitrate
can be reduced, usually to elemental nitrogen (N?) if denitrify-
ing conditions exist and lost to the atmosphere by volatiliza-
tion.
Applied inorganic phosphorus is quickly converted to water in-
soluble forms. Fixation of phosphorus as relatively insoluble
compounds effectively reduces the concentration of phosphorus
in solution. Soil erosion processes may move substantial
amounts of phosphorus as constituents of soil particles and
organic matter.
Water Movement
Management practices must center around not only soil characteris-
tics but the climatological patterns that are prevalent in a
particular area.
Climatological patterns in the United States are surprisingly
consistent from one year to the next. Perhaps the most
important aspect of the yearly climatological cycle is the
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relationship between streamflow, precipitation and evapotrans-
piration. Figure k3 is an illustration of this relationship
for western New York. The general relationship will be similar
in the north^central and northeastern states, although the
actual quantities will vary between regions and years in
response to local climatic -variation. Regardless of the
absolute values for a particular region, the basic concepts
given by Figure h3 will apply.
When evapotranspiration exceeds precipitation in the early summer,
crops become dependent on water in the soil reservoir. Under
'average' conditions, there is not a surplus of water and
nutrient movement is localized. Surface runoff, however,
can occur anytime that the intensity of a rain storm exceeds
the infiltration rate or percolation rate of the soil. During
the late summer and early fall months, precipitation begins to
exceed evapotranspiration, but there is generally no appreciable
increase in water movement out of the soil profile because of
soil water recharge -
At the onset of the winter months, precipitation continues to
exceed evapotranspiration and the capacity of the soil water
reservoir becomes exceeded. When the soil becomes saturated,
excess water is available for percolation through the soil
profile to underground aquifers. Surface runoff is most
prevalent because of the restrictions of water transmission
through the soil. Continued ground water recharge as well
as surface runoff causes a rise in streamflow. The period
when the largest flow of water is likely, and hence, the period
of major nutrient movement is during periods of high stream flow.
For the northern states, this occurs in late winter and early
spring runoff.
The management of land disposal of manure must be oriented
around the practices that will best prevent sediment and
nutrients from being carried by runoff and nutrients from
being leached out of the 'active1 portion of the soil profile.
Nutrient Management
A system of recycling for plant nutrients cannot be main-
tained unless these added nutrients are utilized by a
growing crop. The greater the capacity of a given crop to
reduce nutrient losses by reducing erosion and utilize the
constituents in manure, the greater the amount of manure that
can be added. It is well known that the closer plant nutrients
are applied to the time of maximum demand by a crop, the
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I2.5
Sao
z
o
uj
Q_
CO
UJ
o
2.5
r. rn O 'Q
D—n
OFVAPOTRANSPIRATION
O
-------
greater will be the efficiency of utilization.. This will
in effect, insure that the soluble constituents do not remain
in the soil for an extended period.
In the north central and northeastern states, there are few
actively growing crops from early fall until late spring. This
time coincides with increased water movement. Consequently,
manure additions in the fall and winter may create an excess
of plant nutrients that will "become subject to transport. Once
these nutrients are either transported off of the field or
below the root zone, they are lost from the cyclic system, and
nutrient enrichment of waters may occur. Manure applications
made during the late spring and summer months, after maximum runoff
and leaching have occurred, allow for more efficient utilization
of nutrients by plants. Disposal of manure on the land in late
spring is not always easy to achieve. It is difficult to apply
a substantial percentage of the manure just prior to planting a
crop, especially if daily spreading is practiced.
Nitrogen recycling appears to be the prime objective because of its
solubility which makes it easily subject to transport from the dis-
posal area. Manure application rates to the land should closely
relate to the estimated annual crop usage of nitrogen. It is assumed
that if nitrogen movement is controlled, conservation of other con-
stituents in manure will follow.
Undesirable losses of nutrients to surface and groundwater
will be reduced by well planned manure-soil-crop management
practices. Animal wastes should be utilized as a primary source
of fertilizer. Mineral fertilizers should be used only to make
up remaining deficiencies.
LAND APPLICATION
When manure is spread on the land, the following conditions need
to be met: a) surface runoff should be controlled; b) the soil
and vegetation should serve as a 'sink' for nutrients contained
in the manure so that surface and groundwater are not excess-
ively enriched; c) odors should be controlled. If these conditions
exist, the resulting system allows the nutrients from the manure
to be recycled to crops to animals and to crops again with min-
imum losses.
Principle pollution potentials of manure are associated with:
(a) inadequate manure storage facilities, and (b) excessively
high rates of manure applications. Excessive losses of_manure
and/or its soluble constituents can result in: a) nutrient
127
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enrichment and oxygen depletion of water courses; b) nitrogen
enrichment in potable water supplies; and c) the possible
transmission of disease.
Conservation Practices
Many nutrients in manure can be lost between the time of deposi-
tion by the cow and the time they are available to the growing
plant.
Some of these losses are:
(a) Volatilization of nitrogen in the form of ammonia or
denitrification products. The denitrification mechanism
does not contribute significantly to local water pol-
lution problems.
(b) Surface runoff losses of nutrients as contained in the
liquid fraction or sediment.
(c) Leaching losses of soluble nitrogen as water moves through
the soil profile. Eventual recharge of the underground
reservoir may become enriched with soluble nitrogen.
Land application schemes for the disposal of animal wastes must
contain sound management practices to prevent the loss of nutrients
via surface runoff and leaching. Diversion of surface water from
areas outside the cropped region is an important control measure.
Frequently, surface water from upper-lying non-cropped areas can
be intercepted above the spreading field and delivered to a
suitable outlet. Technical assistance with soil-water manage-
ment problems and control practices are available through the
Soil Conservation Service. Advice can also be obtained
from the local county Extension Service.
Proper Management Techniques
Most dairy manure in the north central and northeast region is
handled either as a solid or semi-solid. The manure may or may
not contain bedding and will not have any extra liquids added.
Application is usually done with a conventional manure spreader
on a daily basis. Liquid manure contains a higher percentage
of water and is usually stored until disposal is convenient.
Application methods include surface spreading, plow cover
furrow methods and irrigation. Irrigation with liquid manure
is still in the development stage and consists of a storage area,
pump and necessary pipe to convey it to the disposal area. It
may have only limited use in some areas, because of odors and soil
topography.
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When a choice is available, manure should "be spread on fields
that are: (l) well and moderately well drained; (2) are the
least sloping; and (3) contain the greatest amount of vegetation,
Manure should always be spread as uniformly as possible. This
uniform coverage allows a given amount of manure to come into
contact with the largest surface area of soil and/or vegetative
cover. Liquid manure spread from storage facilities should be
incorporated immediately with the soil especially where odors
may effect nearby residences. Incorporation with the soil not
only greatly reduces odor, but also the chances of manure
movement by surface runoff. Incorporation may be impractical
except where soil injection systems are used, or applications
made prior to spring or fall plowing.
Liquid and semi-liquid manure requires somewhat more careful
management than does solid manure because it is more susceptible
to runoff.
Timing of Application
The best time to dispose of manure is when it is most likely
to remain where it has been applied. Common cropping practices
and weather conditions make this time appraisal somewhat dif-
ficult. The following management practices will help to min-
imize the movement of manure by runoff:
Fall -
Apply manure to those fields containing the greatest amount of
vegetation or crop residue. A hayfield that will be plowed the
following spring would be an excellent choice.
Secondary choices would be those with somewhat less crop residue
such as a corn field, small grain stubble or fields grown up to
weeds and small brush can also be used.
Fields that are to be fall plowed make excellent choices for
manure disposal. Immediate plow down is advantageous because:
a) the soil can immobilize some of the nutrients contained^in
the manure; b) manure is not exposed to surface waters during
fall, winter, and spring runoff. Areas that are to be plowed
for non-leguminous crops (corn, etc.) the following spring
should have precedence over fields that will be planted to
leguminous crops (alfalfa, etc.). The former will utilize
nitrogen more efficiently.
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Winter -
The major problems with winter spreading are frozen soil or
deep snow which may make fields inaccessible. Frozen soil is
relatively impervious to water, making runoff eminent during
thaws, which is compounded if accompanied by rain.
Accumulated manure from storages should be spread in November
or early December before the beginning of continuous snow cover.
If a snowpack or an ice sheet develops later, it will be over,
rather than under, the manure. This will provide some pro-
tection from runoff. Ideal disposal areas would be fields that
contain vegetation to be plowed in the spring (sod, stubble, etc.).
For daily spreading programs, the distance to and accessibility
of fields to be used for winter spreading should be considered.
Areas having limited access should be used early in the winter.
Easily accessible land can be used during periods of deeper
snow cover. This schedule will help to avoid overloading
fields close to the barn when the snow is deep.
Spring -
Manure used in a daily spreading operation should be applied to
fields that are to be plowed. Stored manure should be applied
and plowed down just prior to spring planting. This reduces the
time period during which soluble nutrients are subject to leach-
ing. A growing crop can utilize these nutrients, reducing
losses to the environment.
If manure is spread on meadows, a grass hayfield or a legu-
minous hayfield in its last year of production would be appro-
priate. The rate of application should be low enough so as
not to interfere with the first cutting of hay.
Summer -
Summer applications may be made on meadows, wheat and oat
stubble, unused pasture areas, weedy non-crop areas, or
fields with light brush growth.
Rates of Application
The suitable rate of manure application is determined by the ability
of the soil/crop combination to immobilize and utilize the nutrients
in manure. The greater the crop requirements for plant nutrients,
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the greater the amount of manure that can be applied, however soil
characteristics may be the limiting factor. The applied nutrients
. nrens
must remain on or in the soil long enough to benefit the crop Soil
depth, drainage and slope are important considerations.
The suggested maximum application rate is 6? t/ha/yr (30 t/acre) and
is based on the best available knowledge at this time! The maxima
rate is determined by the approximate amount of nitrogen that will
be available the first year assuming a 0.5% N content of the fresh
weight. Additional suggested rates, if the maximum is not desired
for several crops are as follows: '
Sl2£. Rate, t/ha/yr
Corn IJ.E;
Grass-hay 35
Oats 20
Additional starter fertilizer at planting time may be necessary and
it is suggested that local University recommended rates for fertilizer
in combination with manure application be consulted.
Tables 31, 32 and 33 present rates depending on various soil character-
istics. Rate calculations should be rounded to the nearest 10 t/ha.
Table 31. SUGGESTED RATES OF DAIRY MANURE APPLICATIONS FOR PLOW-
DOWN OR INJECTION (APRIL 1 - SEPT. l) AS A PERCENT OF
THE MAXIMUM RATE.
Slope, % 0-3 3-8 8-15
Rate 100 100 100
Table 32. SUGGESTED RATES OF DAIRY MANURE APPLICATIONS FOR SPRING
AND SUMMER TOPDRESSING (APRIL 1 - SEPT. l) AS A PERCENT
OF THE MAXIMUM RATE.
Slope, % 0-3 3-8 8-15
Rate 100 50 30
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Table 33- SUGGESTED RATES OF DAIRY MANURE APPLICATIONS DURING FALL
AND WINTER MONTHS (SEPT. 1 - APRIL l) AS A PERCENT OF
THE MAXIMUM RATE.
Soil depth to "bedrock, cm
50 - 100
0-50
Slope, %
Drainage
Excessive
(sand or gravel substrata)
Well
Moderate
0-3 3-8 8-15
50 50 30
10° 50 30
0-3 3-8 8-15
60 30 20
Somewhat Poor
30 15
10
* Rarely occur.
LEGEND
1 .
2 .
Slope
a. 0
b . 3
-3% -
c.
8 -
Drainage
a. Excessive
b . Well
c. Moderate
d. Somewhat
Poor
e. Poor
Level to nearly level.
Nearly level and gently sloping to sloping and
strongly sloping.
Strongly sloping to moderately steep.
Water is removed from the soil rapidly to
very rapidly
Water is removed from the soil either rapidly
or readily
Water is removed from the soil somewhat slowly.
Soil profile is wet for a small but insigni-
ficant part of the time.
Water is removed from the soil slowly enough to
keep it wet for significant periods but not all
of the time.
Water is removed from the soil so slowly that it
remains wet for a large part of the time. The
water table is commonly at or near the surface
most of the year.
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SECTION V
AW ECONOMIC IMPACT AND WATER QUALITY EVALUATION
OF CERTAIN PROPOSED AHIMAL WASTE DISPOSAL LEGISLATION WITH
RESPECT TO DAIRY FARMS
INTRODUCTION
All agricultural operations have an impact of some significance on
quantity and composition of ground and surface water leaving the
area. There are numerous alternative diets and numerous agricul-
tural production schemes to supply these diets available to the
American people. The specific alternatives ve have investigated
here are those concerned with milk production.
Major attention is devoted to the nutrient losses associated with
the disposal of the dairy manure in various crop production schemes
associated with production of the feed for the dairy cows. In
effect we wish to combine the crop production and manure disposal
aspects of milk production so as to keep the costs of milk produc-
tion at a level which ensures its availability to all income groups
and yet not degrade water quality to an unacceptable level. As a
first approximation, the two factors, cost of milk and nutrient
addition to water, are inversely related and more or less continuous
functions. That is, there are essentially an infinite number of
management schemes which produce a corresponding number of paired
milk production costs and nutrient losses such that generally the
production costs of milk will increase as restrictions are placed on
the amount of nutrients which can be lost in ground and surface water
leaving the dairy farms.
Most of the present legal procedures are of very little value in
the control of the downward movement of contaminants through the
soil and into the groundwater. Proof of the source of the contamin-
ant, and proof of the causative negligence, is extremely difficult
to establish for most of the materials commonly involved in agricul-
tural pollution by runoff or through groundwater. It is no less
desirable that this type of pollution should be controlled. Up to
the present time, however, there has been little agreement on the
details of the controls which might be suitable. Attempts are
being made to standardize and put such controls on a quantified
basis, but the most common approach at the present time is to leave
the decision with some appropriate authority as to whether a farmer s
practice or proposed practice is acceptable or not.
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Consideration of the problem of writing legislation to control
agricultural pollution should include the points of view of the
farmer, the legislator, the administrative agency and the environ-
mentalist. For the purposes of this study, there are the following
primary objectives of legislation:
1. To prevent or reduce pollution - biological, chemical,
visual,
2. To conserve material nutritional to plants and animals.
3. To encourage the formation of stable soil physical con-
ditions.
U. To maintain favorable relationships between farmers and
the public.
These objectives might be achieved by a combination of one or more of
the following approaches:
1. To prohibit certain practices under conditions which
make them undesirable, as would be the case if they
violated any of the four objectives listed above.
2. To make it possible to easily identify those with the
potential to cause the problems which are to be con-
trolled so that compliance with the law can be readily
established.
3. To make compliance with the law desirable and attractive
to the farmer in order to reduce the need for enforcement.
k. To make the farmer responsible for proving compliance with
the law.
It is probably not desirable to construct rigid regulations which
force a farmer to adopt methods and procedures which are not optimal
for his operation. There are many ways to modify farm practices to
achieve the objective of reduced pollution. Farmers should be en-
couraged to use all the ingenuity at their command to achieve these
objectives, rather than to simply comply with a uniform set of con-
ditions prescribed by a Pollution Control Board*.
* Dr. S. R. Aldrich, personal communication, Illinois Water Pollution
Control Board, 1972.
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It is not the intention of this study to enter into the arguments as
to whether or not agricultural practices, and animal wastes in par-
ticular, are a major contributor to pollution. It has been established
that there is not only a potential for pollution, but that farm animal
wastes do frequently contribute to lower water quality and odor and
fly problems (5, l6). This section is concerned with the identifi-
cation and selection of the type of legislative controls which might,
in the foreseeable future, be enforced.
Many of the assumptions and methods of approach used to formulate the
linear model was developed from the findings of the three year study
dealing with land application. This phase has been discussed in
Section III.
Those factors which legislation may attempt to control can be briefly
summarized as follows:
1. Soluble organic material capable of causing a lowering
of dissolved oxygen levels in water on microbial degra-
dation. This oxygen depletion may cause, and has caused,
fish kills.
2. Nitrogen, both inorganic and organic forms which can be
released as inorganic nitrogen after degradation. Ammonium
and nitrate nitrogen fertilize undesirable growths of
aquatic flora, and, with nitrite, can be toxic to man
and animals when ingested in large enough quantities.
3. Phosphorus, both inorganic soluble forms and organic phos-
phorus which may be released on degradation. Phosphorus
is necessary for the growth of aquatic flora.
U. Suspended solids. Sediments cause siltation of waterways
and sludge banks contain organic solids which can xause
oxygen depletion and the production of noxious gases on
decomposition.
5- Volatile materials such as hydrogen sulfide and organic
compounds which cause undesirable odors.
6. Color and turbidity of water causing decreased aesthetic
values.
7. Pathogenic organisms such as bacteria, viruses and para-
sites in various forms and life stages which may be infec-
tious to humans or other animals or both.
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8. Pests such as rodents, flies and mosquitoes.
9- Unsightly appearances which detract from rural amenities,
The summary above includes many items which are common to the un-
desirable waste characteristics of any source such as industry and
municipalities (6). Some, such as items eight and nine, are fre-
quently, "but not uniquely, a problem with a large scale animal
operations (l6).
A review of the available literature on existing and proposed laws
and guidelines has been made. It is possible to discern a number
of specific approaches to the problem of controlling the problems
listed above. The fact that many of these approaches are still
proposals and have not yet been included in actual legislation
should not detract from the need to give them adequate considera-
tion. If public pressure continues to increase, and if officials
respond by becoming bolder, these proposals will undoubtably be
given greater attention and possibly enacted into law. Possible
approaches may be summarized and listed as follows:
1. To restrict the amount of manure which can be spread
on a unit of area in one year.
2. To restrict the quantity of nitrogen and/or phosphorus
which may be spread on a unit of area in one year.
3. To restrict the spreading of manure to soils which
are not excessively permeable or excessively imper-
meable .
U. To restrict the spreading of manure to flat or only
gently sloping fields.
5- To restrict the spreading of manure to areas greater
than some acceptable distance from surface water
capable of leaving the operator's property.
6. To restrict the spreading of manure to certain times
of the year.
T. To restrict the spreading of manure to areas greater
than some acceptable distance from dwellings and areas
to which the public have access.
8. To require that a certain minimum land area be owned
or controlled by the farm operator according to the
quantity and type of animals kept.
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9. To require that any form of manure disposal, other than
land application, meet the same controls and standards as
those required for industrial or municipal effluent disposal.
10. To require that treatment, handling and storage of manure be
such that no disease, odor, insect or rodent nuisance is
caused. Note: In the above list, it is assumed that "manure"
refers to fresh, stored, or treated animal wastes.
Just what the various distances, permeabilities, slopes and applica-
tion rates should be for use with the ten proposals listed above is
far from certain. It must be kept in mind that the purpose of the
controls is to meet the primary and secondary objectives listed
previously. It may be argued that there is insufficient data at
this time to allow any decisions to be made. While this may be
partially true, it must be remembered that this same lack of data
has not prevented many government agencies from issuing guidelines
to accompany approval certificates for livestock operations.
It remains the purpose here to estimate some of the values which
might be used with each of the proposed regulations. These will
enable a set of restrictions to be outlined which will represent
a range of legislative severity. Existing and proposed regulations
and several examples are given in Tables 3^ and 35 -
Table 36 lists hypothetical controls at two levels. These levels
approximate what can be considered an "intermediate" degree of
pollution control, and a "high" degree of pollution control.
It has been the intention in presenting this discussion to pre-
pare the reader with the background needed to interpret Table 36.
Briefly, the rationale behind these hypothetical controls is as,
follows (numbering corresponds to numbered sections of the table):
1. A limit of 112 Met. tons/ha (50 tons/acre) of manure
is likely to avoid gross pollution by runoff and
aesthetic impairment. At restriction level 2, however,
the intention is to limit manure to a level where there
is little possibility of there being excess nitrogen for
excessive leaching.
2. The fertilizer limits correspond to the manure nutrients
in (l) above, assuming approximately 10% manure H avail-
able or mineralized over a period of years, the remaining
N being assumed to be volatilized. At restriction level
2, there is a lower denitrification allowance because of
the lower levels of undecomposed organic matter where there
is no manure application.
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Table 31*. SUMMARY OF EXISTING AND PROPOSED STATE REGULATIONS TO CONTROL LIVESTOCK
RELATED POLLUTION, a
co
oo
Situation
type
a
Existing laws requiring registration
of certain livestock operations.
Arizona, Colorado, Florida, Indiana,
Iowa, Kansas, Minnesota, Nebraska,
North Dakota,.Oklahoma, South Dakota,
Texas b'c'd
Existing laws to control wastes from
livestock operations "but with no reg-
istration requirement.
Illinois, Ohio, Wisconsin
b,c
Registration requirements for waste
discharges.
Maine, Massachusetts, New Jersey,
lew York, Pennsylvania, Rhode Island,
Florida c
Discharge requirement without
registration.
Almost all states, other than those
listed under 3 above.
Waste disposal administrative codes.
Arizona, California, Colorado, Indiana,
Iowa, Kansas, Maine, Missouri, Mass-
achusetts, Minnesota, Nebraska, Oklahoma,
Texas c
Other proposals.
Unknown total number.
Not necessarily complete as these regulations are constantly changing.
Lutz,
Johnson et al., (39)
d Schwiesow, (62)
-------
Table 35. EXAMPLES OF EXISTING AID PROPOSED STATE REGULATIONS TO CONTROL LIVESTOCK
RELATED POLLUTION,a
Situation
type
State
Application criteria
Conditions
co
Iowa 1. >1,000 head of cattle in confine-
ment .
2. If runoff contributes to a water-
course draining an area of 1300
hectares or more and confinement
less 0.6l m (2 ft) per head of
cattle in the confinement from
this water course.
3. If runoff from confinement lot or
from retaining lagoon flows into
a drain conduit, any type of
well, or into a sinkhole.
Applicable to any operation where
there are at least 100 head of
cattle, or where density is greater
than 1 animal per 56 m2 (600 ft2)
Retention ponds and terraces
must be able to contain at
least 7-6 cm (3 in.) of run-
off water from all waste con-
tributing areas. Settling
basins must be provided for
solids separation before run-
off reaches retention ponds.
Waste treatment may be per-
mitted with permission of
Dept. of Health. Retention
ponds must be emptied as
soon as possible after run-
off.
Proposed: Approval of waste
disposal practice based on
information supplied as to
soil types, use of land be-
tween confinement and stream,
slope of land, infiltration
rate, control of waste dis-
charges in relation to stream
flow and distance to dwellings,
Wastes may be spread on land
surface, irrigated, or mixed
into soil in such a way as to
prevent runoff of wastes. All
other methods subject to
individual approval.
-------
35- (Continued) EXAMPLES OF EXISTING AMD PROPOSED STATE REGULATIONS TO CONTROL LIVESTOCK
RELATED POLLUTION.a
Sltuation
type
State
Application criteria
Conditions
3
Florida Any livestock or animal waste abatement
installation considered a potential
source of water pollution, and all
firms with waste systems handling more
than 227 kg BOD.- (500 Ibs)
Maine
d
Subject to approval.
Applies to: Total annual animal and
poultry manure production after
removal from the barn or storage area.
Covers: Manure use "by crop production;
disposal of excess by land spreadings,
stockpiling, burying in landfills,
composting, lagooning, irrigation,
drying.
3.
U.
No spreading on frozen ground.
Exception in upland soil with
less than 3% slope in which
case limit is manure or waste
with nitrogen content of 280
kg/ha (250 Ibs/ac).
Tabulated nitrogen applications
for each soil type in the state
are limit for total nitrogen
including fertilizer.
No waste less than 7-6 m (25
ft) from water body.
No waste less than 30 m (100
ft) from spring, well or lake.
No spreading near lakes if
runoff probability high.
No spreading on slopes greater
than 25%.
-------
Table 35- (continued) EXAMPLES OF EXISTING MD PROPOSED STATE REGULATIONS TO CONTROL LIVESTOCK
RELATED POLLUTION.a
Situation
type State Application criteria Conditions
5
Maine
(cont'd)
T. No spreading in depressions
which carry water during
snow melt or heavy rainfall.
8. Tabulated maximum nitrogen
applications to crops from
fertilizer or waste (crop
must be harvested) - example
corn - 280 kg/ha (250 Ibs/
ac); oats - 56 kg/ha (50
Ibs/ac) etc.
9. No dumping on floodplain
unless waste is plowed under.
10. Dumping may be done at
rates up to 673 kg/ha
600 Ibs/ac) of nitrogen if
a crop is removed. Other-
wise limit is 56l kg/ha
(500 Ibs/ac) nitrogen.
11. Stockpiling only allowed on
certain soils.
12. Stockpiled wastes must be
removed within one year.
13. Stockpiling of wastes cannot
be on slopes greater than
8% or within 91 m (300 ft)
oT WC+.PT- Tidies, streams,
wells or springs.
-------
Table 35- (continued) EXAMPLES OF EXISTING AND PROPOSED STATE REGULATIONS TO CONTROL LIVESTOCK
RELATED POLLUTION.a
Situation
type State Application criteria Conditions
Maine
(cont'd)
lit. There are many conditions relating
to composting, burying, etc.
15- Every soil in the state has "been
classified and limits applied
for each of the activities listed
above.
New York
Proposals
Guidelines
to
Limit liquid and solid manure appli-
cations to nitrogen need of crop.
Semi-solid manure (13-18$ dry matter)
limit 67 Met. ton/ha (30 tons/ac).
Spring or summer plowdown - 100% of
maximum rate; spring and summer top-
dressing - 2U$ to 100$ of maximum
depending on soil slope; fall and
winter applications - 8% to 100$ of
maximum depending on soil slope,
depth and drainage class (given in a
table).
Illinois6
Proposals
Legislation
Nitrogen - 50 kg/ha (50 Ibs/ac)
in fall; 3^ kg/ha (30 Ibs/acre) in
fall, on fall seeded crops only, on
sandy soils; none on slopes greater
than 5% when frozen; maximum rates
at other times of year depending on
crop and soil type, and whether ir-
rigated or not.
-------
Table 35 - ( Continued) EXAMPLES OF EXISTING AND PROPOSED STATE REGULATIONS TO CONTROL LIVESTOCK
RELATED POLLUTION.a
Situation
type State Application criteria Conditions
co
Illinois
(cont'd)
Phosphorus - none if slope greater
than 5% and soil frozen; 56 kg/ha
(50 Ibs/acre) limit on organic soils
(soils with greater than 20% organic
matter).
Manure - no spreading on soils with
slopes greater than 5%5 within 201 m
(650 ft) of a stream or lake, when
soil is frozen; none in natural drain-
age or waterways. Other limits for
sludge and effluents.
Wot necessarily complete as these regulations are constantly changing.
13 Agena, (2)
Johnson et al., (39)
Maine Special Statewide Committee.
e Undefined.
j>
Klausner, (U3)
^ Anonymous, (1)
-------
Table 36. SUMMARY OP POTENTIAL WASTE DISPOSAL REGULATIONS AT TWO LEVELS.
Parameter
Restriction level 1
Restriction level 2
1. Application rates of
manure
112 Met. tons/ha (50 tons/
acre) (unless covered im-
mediately in which case
280 Met. tons/ha (125 tons/
acre)
Expected plant uptake of N +
9 Met. tons/ha (U tons/acre) for
OM maintenance + 30% denitrifica-
tion allowance - 1.2$ of organic
N in soil
Nitrogen and phos-
phorus application
rates
448 kg/ha (400 Ibs/acre)
total N; 22U kg/ha (200
Ibs/acre) total P 0
Expected plant uptake + 15$ de-
nitrification - 1.2$ of organic
N in soil
Soil characteristics
(permeability)
56 Met. tons/ha (25 tons/
acre) if permeability is
rapid (l6 cm/hr) and no
wastes with D.M. <15$. 56
Met. ton/ha (25 ton/acre)
if perm. <.5 cm/hr and slope
>10$
No manure with D.M. <15$if perm.
is rapid (>l6 cm/hr) or if slow
(<.5 cm/hr) and slope
No manure with D.M. <15$ on
slopes >5$. No manure on slopes
>20$
4. Slope
No manure with D.M. <15$ on
slopes >10$
No manure <15 m (50 ft) -
slope >10$; No manure with
<15$ D.M. 30 m (100 ft) if
slope >5$
5. Distance from surface
water capable of
leaving farm
No manure <30 m (100 ft) if sodded,
<60 m (200 ft) if cultivated. No
manure with <15$ D.M. 76 m (250 ft)
if sodded or 152 m (500 ft) if
cultivated
-------
Table 36. (Continued) SUMMARY OF POTENTIAL WASTE DISPOSAL REGULATIONS AT TWO LEVELS.
Parameter
Restriction level 1
No manure with <15$ D.M. if soil is
frozen
Restriction level 2
6. Time of year
No manure between Dec. 7 & April 21
or at any other time if soil is
frozen
7- Distance to
nearest dwelling
or public access
No anaerobic liquid or slurry <152
m (500 ft) from non-farm dwellings,
No manure 30 m (100 ft) from dwell-
ings or public access
No anaerobic liquid or solid <302 m
(1000 ft) from dwellings. No manure
< 152 m (500 ft) from dwellings or
access; No irrigation (spray) < 906 m
(3000 ft) from dwellings or public
access. No storage <302 m (1000 ft)
from dwellings or <75 m (250 ft)
from public access.
8. Minimum land
area
.Ok ha/animal unit(0.1 acre/
animal)0
0.2 ha/animal unit(.5 ac/animal
dt)c
unit
9. Treatment
secondary - <60 mg/1 B.O.D. <60
mg/1 S.S., <20,000 coliforms/
100 ml.
Teritary - <30 mg/1 BOD, <30 mg/1
SS. <100 coliforms/100 ml, <10 mg/
1 N, >9Q% removal of P.
10. Disease control
No spray irrigation if wastes
from animals infected with com-
municable diseases, as determined
by a veterinarian, within 302 m
(1000 ft) of dwellings or public
access
No spray irrigation of wastes from
animals infected with communicable
diseases as determined by a vet-
erinarian. No pasturing of animals
on pasture within 3 months of manure
spreading on that land. No pastur-
ing if infected animals within 152 m
(500 ft) of surface water.
-------
Table 36. (Continued) SUMMARY OF POTENTIAL WASTE DISPOSAL REGULATIONS AT TWO LEVELS.
Q
"Intermediate" level.
"High degree" of pollution and disease control,
c It5It kg live-weight (1000 rbs)
Oi
-------
3 & U. Physical effects of manure applications are likely to
be influenced by the physical nature of the manure. The
15% dry matter division between "liquid" and "solid"
manure is set at approximately the limit of pumpability.
Liquid wastes are assumed to percolate and runoff more
readily than solid manure.
5. In addition to the greater runoff risk expected with
liquid wastes, this section allows for differences in
the type of crop on which these wastes are spread at
restriction level 2. Runoff is likely to be less in
quantity and of better quality from sodded slopes than from
cultivated, so that different distance limits from surface
waters have been provided.
6. It is assumed that liquid manure is likely to have a higher
runoff potential from frozen soils than solid manure. At
restriction level 2 it is intended that no manure will be
spread when there is a 1 in 12 probability of frozen ground.
7. This section recognizes that liquid manure is often anaer-
obically stored, and consequently highly odorous. At
restriction level 2, it also considers the aerosol drift
from irrigated wastes, and the risk of pathogen trans-
mitt al by this route.
8. The requirement for a minimum land area is designed to
provide adequate isolation, and some land area for manure
disposal at two levels.
9. The discharge characteristics have been included in this
set of control measures so that recognition could be
made of the desire of some operators to treat and dis-
charge their wastes. The limits chosen represent a
high level of treatment even at restriction level 1.
10. This restriction is intended to give recognition to
the problem of disease transmission from infected
animals to humans or animals.
METHODS
The purpose of the procedures described in this section is to
enable estimates to be made of the economic, agronomic and environ-
mental effects of some of the hypothetical legislation and restrictions
147
-------
previously described. Definitions may be found in the Glossary. The
model is made up of two distinct steps as described in Figures hh
and hj.
Step I
The first step is one in which a computer program is used to analyze
data given for a dairy farm. The program calculates values associa-
ted with a large number of alternative agronomic activities, and
stores them for use in Step II (see Figure kk). It can be seen
from Figure kh that the program treats each soil area as a separate
entity. Every year of every crop in each rotation, which can be
grown on a particular soil area, is treated separately. When the
application (or not) of manure at any time of the year is included,
this unique cropping situation becomes a "land use activity."
Step I is made up of three sections which can be distinguished
as follows:
gutrient Analysis -
Referring to Figure 1*5, it can be seen that nutrient inputs to the
model are as rainfall, fertilizer and feed. Losses occur as vol-
atilized ammonia, denitrification, leaching, runoff, soil erosion
and the sale of crops and animal products off the farm. The
manure and fertilizer application rates control the rate of nutrient
return to the soil, and consequently influence the rate of loss from
the field.
Economic Analysis -
This section analyses the inputs of labor, feed, fertilizers, and
other inputs into the activities which grow crops and raise animals
(see Figure 1*6). A careful accounting procedure is used to record
the input and production costs associated with every "land use
activity," and keep track of the production of feed from each of
these activities for use as input for the livestock activities.
Only surplus crops are sold off the farm, unless it is more
economical to buy feed and sell the crops which have been grown.
Environmental Parameters -
This section consists of a number of sub-models. These sub-
models estimate the expected runoff and soil losses from each
cropping activity on each soil area. They utilize information
generated by sections above, to predict the losses of nutrients in
the runoff and eroded soil. The expected loss of nitrogen by
148
-------
•*[^TL~AREA]
H ROTATION
pYES —
IXiMEj
MANURE
RATE!
FERTILIZER
EQUIVALENCE
I
H FERTILIZER]
[COSTS'
YIELDS
RETURNS
SOIL LOSS
RUNOFF
LOSSES TO
ENVIRONMENT
NO-
END OF ROTATION
YES
-[LAST ROTATION
YES
NO-JLAST SOIL AREA
STORE ALL
INFORMATION
ON TAPE
YES
Figure
Schematic representation of the model - Step I.
149
-------
SOLD OFF
FARM
I
FEED
(TON, DP)
NH;
NH3
ANIMAL
(TYPE)
(AGE)
STORAGE
1
MANURE
(N,P,K)
(HANDLING SYSTEM)
RAINFALL
(N)
FERTILIZER
(N, P,K)
APPLICATION
RATE
n
[SOLD OFF FARM
CROP
(TYPE)
(STAGE OF GROWTH)
(NUTRIENT NEEDS)
SOIL
(TYPE)
(SLOPE)
(ORGANIC MATTER)
(MINERALIZATION)
(DENITRIFICATION)
SOIL EROSION
(N.P)
RUNOFF
(N)
PERCOLATION
(N)
Figure 1*5.
Step I, Schematic representation of the
functional relationships of the model -
nutrient analysis.
150
-------
PRODUCTS
SOLD
FEED
PURCHASED
LABOR
FEED
GROWN
I t f.
J
ANIMAL
(TYPE)
I LABOR
HOUSING
MANURE
HANDLING
DRAINAGE
LIME
EQUIPMENT
SOIL
(LOCATION)
(PRODUCTIVITY)
FERTILIZERS
CROP
(TYPE)
(YIELD)
(TON, DP)
(STORAGE)
(HANDLING)
PRODUCTION
INPUTS
CROP
SOLD
Figure 46. Step I, Schematic representation of the
functional relationships of the model -
economic analysis.
151
-------
percolation and by denitrification is found by the difference
between the expected inputs and outputs of N from each soil area
under each cropping activity.
StepII
In Step II (see Figure ^7), the accumulated information on the
alternative land use activities for the farm is incorporated with
input data on the non-agronomic (non-land using) activities such
as the dairy operation and the buying and selling of feed and crops.
The resulting data is passed through a linear programming pro-
cedure which selects that combination of all of the activities
which gives the maximum income to the farmer. At the same time,
this selection must not violate any of the restrictions which
are imposed upon the farm operation by selected portions of
the hypothetical legislation previously described. During this
selection procedure which is accomplished by linear programming,
the land area of the farm is held constant, and the number of cows
in the dairy herd is ranged from zero to 150. A complete set of
solution values are obtained at each increment in herd size, so
that a range of solutions may be plotted for each set of hypothe-
tical restrictions. The solutions are plotted and discussed.
A computer program has been written in FORTRAN V to handle Step
I of the model. This conducts the nutrient and economic analyses,
computes the values of the environmental parameters, and prepares
the data for input to Step II, the linear programming optimization
procedure.
VALIDATION OF THE MODEL
In the context of the model used in this study, one of the prin-
cipal reasons for modeling is that the only alternative, conducting
field experiments, is almost totally infeasible. Field experiments
to collect comparative data of the type used in this study would
be extremely expensive and would take many years to complete.
Furthermore, it may be impossible to obtain identical field situa-
tions large enough for this type of study to be conducted with
any degree of experimental accuracy. This is not to imply that
modeling is a substitute for real data. Rather, it is an extension
of the experimenter's capabilities to infer conclusions from that
data which he already has, and point out what types of data should
be collected in future research.
If experimental data could be obtained readily and inexpensively,
modeling might not always be desirable. The advantages of conducting
152
-------
*
TAKE LAND
ACTIVITY
INFORMATION
FROM INPUT DATA
TAKE NON-LAND
ACTIVITY
INFORMATION
FROM INPUT DATA
INTRODUCE
INFORMATION ON
CONSTRAINTS
UPDATE VALUES OF
PARAMETERIZED
VARIABLES
FIND
OPTIMAL
SOLUTION
UNO-
OF
PARAMETERIZING
YES
PRINT
RESULTS
I
EXIT
Figure kj. Schematic representation of the model
Step II.
153
-------
experiments to make this type of study are that the data which is
measured and collected cannot be disputed, and all variances can
usually be accounted for on the basis of observed field conditions.
With a model, however, it is unlikely that any set of data can be
used without the validity of portions of that data being questioned.
This model is made up of two distinct types of procedures -
those which are essentially accounting procedures utilizing data
which has been measured and is available, and those which predict
the values of certain parameters under a number of different physical
conditions. The nutrient analysis, and the analysis of the economic
factors involved in the model, are procedures of the first type.
Data are available from which representative values may be chosen,
and, while it is recognized that some of this data may be questionable
under certain conditions, it is usually possible to trace and identify
the source of the data, and the conditions which prevailed at the
time the data were collected. With this part of the model, vali-
dation is not necessary.
With the prediction portion of the model, however, it is necessary
to demonstrate that the values which are predicted are reasonable
estimates of what might be expected to occur under any particular
set of field conditions. The purpose of this section, then, is to
present a comparison between values predicted by the model and actual
measured values, as far as this is possible with the limited amount
of experimental data which is available.
Data are presented on the following pages which allow a comparison
of the values of runoff, soil loss, runoff nitrogen, sediment nitrogen
and phosphorus, and expected sum of percolation and denitrification
nitrogen losses which are predicted by the model, with those which
have been measured in the field. The physically measured data were
taken from the research findings during 1971 at the Aurora Research
Farm. Results were from the runoff study in which mineral fertilizers
were used.
The available data is for corn grown on a Lima-Kendaia soil association,
with fertilizers applied at two levels, and with free-stall dairy
manure spread at 35 t/ha (15 tons/ac), 100 t/ha (k5 tons/ac), and
200 t/ha (90 tons/ac). Data is available for wheat at two fertilizer
application levels only. The data for corn was obtained at two
"management levels," roughly corresponding to the removal or retention
of crop residues. These two conditions were considered as approximating
corn grown for silage and for grain respectively.
Runoff
Figure ^8 shows the relationship between the predicted runoff
154
-------
IM EQUALITY LINE
OFERTILIZED WHEAT PLOTS
•FERTILIZED GRAIN CORN
nMANURED GRAIN CORN
• FERTILIZED SILAGE CORN
AMANURED SILAGE CORN
Figure
10 15 20 25
PREDICTED RUNOFF, cm
Comparison between predicted and measured
runoff, 1971-72.
155
-------
quantities and the measured values during 1971 and 1972 on the Water
Quality Plots at the Aurora Research Farm. The actual measured runoff
per acre are shown on the vertical axis, and the predicted values are
given in the same units along the horizontal axis. Predicted values
were determined by regression, using actual values to develop the
equations. The k5° diagonal line represents a perfect 1:1 correlation.
The predicted data points were obtained by modeling both the Lima and
the Kendaia soils, and weighting the average of these according to the
actual distribution of the two soils in each field plot.
Although there is a considerable scatter about the diagonal equality
line, the general relationship between the actual and the predicted
runoff is good. This is especially true if consideration is given
to the fact that the model assumes far more uniformity in the plots
than is found in the field, as can be seen from the figure. The
Water Quality Plots are heterogeneous in many characteristics (see
for example, Swader (69), Jones and Zwerman ClO).
Runoff Nitrogen Losses
Figure 1*9 shows the relationship between the predicted and the ob-
served quantities of nitrogen loss in runoff water from the Water
Quality Plots during 1971 and 1972. All of the remarks made above
relative to the runoff volumes apply also to this figure.
Seepage Plus Denitrification Losses
Figure 50 compares the predicted sum of percolation (seepage) and
denitrification nitrogen loss with the actual seepage nitrogen loss
for 1971 and 1972 at the Aurora Research Farm. The measured values
are from tile drain effluent quality samples. They have been used
to estimate the total seepage loss of nitrogen by adjusting the
seepage volume to compensate for the variations between plots in the
actual area drained by the drain tile lines.
It can be seen from Figure 50 that up to about l^O kg/ha (125 Ibs/ac)
of seepage nitrogen loss the comparison is fairly close. Beyond this
amount, however, the actual loss remains fairly constant while the
predicted seepage plus denitrification loss continues to increase.
The explanation for this would appear to be that the difference
between the two sets of figures is made up of denitrification which is
not measured. Data presented by Pratt (59)» comparing applied nitro-
gen with the concentration of nitrogen in the soil, shows a very
similar trend to that seen in Figure 50.
156
-------
o>
14
12
SlO
o
tr
u.
U-
O
Q
LJ
<
UJ
8
%
D
EQUALITY LINE
D
I/'
OFERTILIZED WHEAT PLOTS
• FERTILIZED GRAIN CORN
DMANURED GRAIN CORN
• FERTILIZED SILAGE CORN
AMANURED SILAGE CORN
/ \ I 1 1 1 1 1 1 ! 1 1 1 1 1 1
2 4 6 8 10 12 14
PREDICTED RUNOFF NITROGEN, kg/ha
Figure U9- Comparison between predicted and actual
runoff inorganic nitrogen loss, 1971-72.
157
-------
350
,-225-
iLl
CD
LU
UJ
LU
QC
cn
<
UJ
D
15
EQUALITY LINE
OFERTILIZED WHEAT PLOTS
• FERTILIZED GRAIN CORN
aMANURED GRAIN CORN
• FERTILIZED SILAGE CORN
AMANURED SILAGE CORN
0 115 225 350
PREDICTED SEEPAGE + DEN1TRIFICATION N, kg/ha
450
Figure 50. Comparison "between predicted sum of seepage and denitrification
nitrogen loss and estimated actual seepage loss, 1971-72.
-------
Soil and Sediment Losses
The sediment data has been presented in Figure 51. It has only been
possible to obtain sediment data for 1972, which was a year in which
there was a very high soil loss due to torrential rains in June. The
factors which have been included in the Wischmeier model for soil
loss (77), do not allow for small variations in soils and slopes or
for wide deviations from average weather conditions. Consequently,
the variability in observed values is greater than that in the pre-
dicted values of soil loss and sediment nitrogen and phosphorus losses,
In 1972 there was only one crop grown, corn, which further limits the
ability of the data to check the model. For these reasons, the
predicted and observed values have been averaged and presented in
histogram form.
The average values for the two crops, corn grain and corn silage are
fairly close to the observed values in the field. It would appear
that the difference between the two crop conditions is being under-
estimated by the model. Without a larger range of crops to compare
soil losses between the model and the field situation, it is difficult
to make more conclusive statements. However, the Wischmeier model has
been widely tested and accepted throughout the Northeast for a number
of years (see, for example, (17 5 22). More than 8,000 plot-years of
data went into the development of the model (76). However, potential
misinterpretation of the predicted soil loss values should not be
overlooked (17), particularly with regard to the distance which this
soil is expected to move.
APPLICATION OF THE MODEL
Step I
Manure -
The manure activities are based on the assumption that manure will
either be utilized as part of the farm nutrient management plan, or
it will be disposed of by dumping on to deliberately unused land. If
the former alternative is chosen, it is assumed that the principal
restrictions on application rates and time of application will be
related to the crop which is being grown. If the latter alternative
applies, limits on the maximum "dumping" rate will be imposed by the
hypothetical controls of the legislation level used for any solution.
The nutrient release from the manure can only be estimated. _ It is
assumed that the inorganic fraction of the manure nitrogen is
immediately available for nitrification, crop uptake or loss to the
environment. The organic nitrogen must be mineralized before loss
159
-------
4.5
C/)
(/>
O
2.3
GRAIN
PREDICTED
MEASURED
SILAGE
o
O
JC
S1 8
to
CO
3 6h
2
Id
O
O
CL
I-
yj
o _
U o
CO U
r NITROGEN pqpRFnirTFn C
| | la^^J
—
_
-
-
^
/y
* *
I
y/
i
[^MEASURED
PHOSPHORUS
'
%
'
%
-
o>
"^
mj^
^
CO
CO
o
_l
to
•=>
QL
O
-ti
PHOSPHI
I-
2Z
^-bJ
&
Q
_UJ
n^n
GRAIN SILAGE
Figure 51- Soil loss, and sediment total nitrogen.and
phosphorus loss comparisons - predicted (A)
vs measured (B) losses.
160
-------
or uptake can occur. The mineralization is assumed to occur only
during those months of the year when temperatures are high enough for
crop growth. Because unmineralized manure organic matter will remain
in the soil until the following year, the mineralization rate has
been estimated for a period long enough for stability of the organic
matter to occur. This figure has been used as an annual mineraliza-
tion rate on the assumption that the system is in equilibrium, and
that manure unmineralized in the year of application is balanced by
the unmineralized manure which remains from the previous application.
Ammonia volatilized from storage is assumed to be replaced by
fertilizer nitrogen, so that a cost was added to the storage costs
to reflect the cost of replacing this nitrogen. Ammonia volatilized
from storage was included in the total potential nitrogen loss by
using the original (before storage) nitrogen content for the calcula-
tion of potential nitrogen loss.
In the calculation of manure application rates at Restriction
Level 2, the volatilized ammonia is excluded by using the manure
nitrogen content after ammonia volatilization. The model does,
however, assume that a portion of the winter stored manure ammonia
nitrogen loss is available for crops if spread in the summer or
fall. Therefore the calculated application rates at these time
periods are slightly lower than would, in reality, be allowed under
the terms of Restriction Level 2 (see Table 37), for manure which
has been stored.
Time Periods -
Although the model is capable of accepting almost any number of
time periods, it was decided that these would be limited to four,
corresponding approximately with the four agricultural seasons. A
greater number of time periods greatly increase the time taken for
the model to be run through the computer. Simplifications were made
in the time periods in the equations of the model where changes were
unlikely to occur between time periods. For example, it was assumed
that the same number of animals were kept during each time period so
that some equations involving animal numbers were simplified to an
annual basis for computational purposes. Equations which deal with
the feed requirements of the animals were simplified in this way.
Similarly, the fertilizer and nutrient loss data were calculated in
the program on an annual basis rather than by time periods, to avoid
the problem of manure and nutrient retention in the soil from one
time period to the next. Equations were simplified in this manner for
computational purposes.
161
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Table 37. RESTRICTIONS USED FOR CONTROLLING MANURE DISPOSAL ACTIVITIES ON TWO HYPOTHETICAL
NEW YORK DAIRY FARMS (SOLID MANURE ONLY). a
Parameter
No restriction
Restriction level 1
Restriction level 2
1. Application
rates of
manure
t/ha (200 tons/
112 t/ha (50 tons/aci
ac
Expected plant uptake of N +
9 t/ha (k tons/acre) for
organic matter maintenance +
30% denitrification allowance
- 1.2% of organic N in the
soil (mineralization)
Oi
to
Nitrogen and
phosphorus
application
rates
none
kg/ha (iMDO Tb/
acre) total N
22k kg/ha (200 lb/
acre) total PO,-
Expected plant uptake of N +
15% denitrification allowance
- 1.2$ of organic N in the
soil (mineralization)
Soil char-
acteristics
(permeability)
surface water
capable of
leaving farm
none
56 Met. tons/ha
(25 tons/acre) if
permeability rapid
(16 cm/hr) 56 Met.
tons/ha (25 tons/acre)
if permeability <0.5
cm/hr and slope
None applicable
It . Slope
5. Distance from
none
none
none applicable
none applicable
No manure on slopes >20$"b
No manure <30m (100 ft) if
sodded or 60 m <(200 ft) if
cultivated
-------
Oi
co
Table 37 (Continued). RESTRICTIONS USED FOR CONTROLLING MANURE DISPOSAL ACTIVITIES ON TWO
HYPOTHETICAL NEW YORK DAIRY FARMS (SOLID MANURE ONLY).a
Parameter No restriction
6.
7.
8.
9-
10.
Time of year none
Distance to none
dwelling or
public access
Minimum land none
area
Treatment none
Disease none
control
Restriction level 1
none applicable
No manure <30m
(100 ft) from
O.OU ha/animal unit
(0.1 acre/animal unit)
none applicable
none applicable
Restriction level 2
No manure during "winter"
time period (Dec. -April)
No manure <151 m (500 ft)
from dwellings or public
access. No storage <151 m
(500 ft) from dwellings or
<75 m (250 ft) from public
access .
0 . 2 ha/animal unit (0.5
acre/animal unit )
none applicable
none applicable
a Essentially same as Table 36, -with controls applicable to liquid manure excluded.
No soil conditions present on the farms used in this study to which this control would apply.
c 145^ kg (1000 Ibs) liveweight
-------
Management Levels -
In this model, only one management competence level is assumed. This
simplification is intended to avoid the problem of generating large
numbers of alternative land use activities, each at a different manage-
ment level. The level of management chosen is approximately that of
the average farmer in the Cost Account Program of the Department of
Agricultural Economics at Cornell University. This asssumption simplifies
the problems of selecting data consistent with any given management
level.
Crop Rotations -
The number of crop rotations for any one farm is restricted to six,
with a maximum of three of these for any one soil type.
Crop Yields -
It is assumed that for a given crop there are three yield levels.
A yield goal can be achieved on a given soil type with the correct
fertility level. Not all yield levels are attainable on all soil
types. The combination of fertility level and yield goal for a
particular soil is a judgment which must be made in the light of
knowledge of the capability of the soil and the expected management
competence of the farmer. Figure 52 shows the relationship of yields
and fertility levels to soil capability. The numbers in the matrix
indicate soil capability from poor (l) to high (5).
3.
2.
1.
yield
level
i
1. 2.
Fertility - ->
3 2
U 3
5 U
3.
3
2
3
Figure 52. Fertility yield matrix for five soil capability
levels.
With additional programming, it would be possible to use production
function data for selecting the optimum application rates of
fertilizer for each crop on each soil type. However, sufficient
164
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data for this to be done with any consistency is difficult to obtain
for the locations and all of the soil types used in this model. As
data consistency is best obtained by utilizing data from similar
sources, the approach above was chosen for yield and fertility expec-
tations utilizing data will be described later.
Fertilizer -
It is assumed that all fertilizer applications are made during the
months of May and June.
The nitrogen, phosphorus and potassium requirements of the crops are
determined from average actual fertilizer levels with and without
manure applications. It is therefore assumed that the contribution of
mineralized organic matter, present in the soil before the manure
application was made, and rainfall have already been accounted for.
Costs -
Certain costs which have been included in the model as variable
costs, such as those associated with crop growing activities,
include some costs which are not completely variable. For example,
costs per acre associated with cultivation and harvesting machinery
have been assumed to be unaffected by the acreage of a particular
crop grown. This assumption greatly simplifies the handling of
cost data for the large number of alternative crop growing acti-
vities and facilitates the use of linear programming for optimiza-
tion.
Structural costs, such as those associated with the animal housing
and milking facilities, have been handled as far as possible as fixed
costs, at each herd size.
Labor -
To simplify the labor distribution between the unpaid labor supplied
by the farmer and his family, and that supplied by the hired help,
it is assumed that the cost of labor in the individual computation
equations is zero, but that hired labor has to be paid for. Thus the
optimal solution is one which utilized all of the unpaid labor, for any
particular time period, before any hired labor is introduced into the
system.
Soil Distribution -
To enable each soil type to have an equal probability of occurring
anywhere on the farm in relation to such physical features as the barn,
165
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roads, streams etc., a circular design was chosen for the farm. Each
soil area (separated by soil type and slope) is arranged as a segment
of the circular farm area (see Figure 53). The barn is assumed to be
located at the center, and since most farms are bordered, at least in
part, by a public road, it was decided to locate a road around the cir-
cumference of the circle. A stream, was arbitrarily located midway
between the barn and the road. It should be noted that the effect
of this design is to have a stream passing through all soil types,
whereas in reality this will not always be the case. However, it is
also possible, in reality, that a soil type which would not ordinarily
have a stream passing through it may be in close proximity to a stream,
as there is often an abrupt change in soil type within a short dis-
tance as creeks are approached. Thus, while the assumption used
may not always be correct, it also may be a close approximation to
reality in many instances. Since the circular design of the farm
minimizes the distance of any point from the barn, transportation
distances for manure spreading are increased by a factor of 39%>
the relationship between the two sides and the hypotenuse of an iso-
soles triangle, to reflect the actual road distances involved in
traveling between points on the farm.
Woodland -
lo deliberate attempt is made to exclude a portion of the farm for
woodland, although it is recognized that the average farm in lew
York has approximately 20% of its soils in woodland. It is assumed
that the optimum solution to the management problem will take into
account the same type of factors which lead a farmer to leave a
certain acreage in woodland rather than cultivate or grow pasture
on the entire farm. Land left idle by the modeling procedure is
assumed to return to woodland. It has been assumed that the amount
of land in hedgerows is not large for any one soil type, and this
potentially unused land is assumed to be included in the land left
idle by the model.
Purchased Feed -
It was originally anticipated that the model should permit the linear
programming solution to include any combination of practices which
would maximize revenue. The costs and crop yields expected in the
one location, as used in the model, are such that when the first
set of solutions were obtained, almost all feed was required to be
purchased.
This is not likely to represent reality, even though it may be the
economically optimum solution for the data used. When the constraints
were altered to require that all forage should be grown on the farm, it
166
-------
BARN
DISTANCE
ZONE
BOUNDARIES
STREAM
ROAD
SOIL TYPES
Figure 53. Physical model of the farm. Area of circle
represents total area of farm. Soil type
zones are distributed around the circle in
proportion to their area on the farm.
167
-------
became impossible to obtain a feasible solution after a herd size of
83 cows was reached. This was partly because of the low yields
expected on these soils and partly because of the rotation requirements,
which were such that crops which did not supply forage were needed to
complete the rotations. Beyond 83 cows there was no solution which
would supply the necessary forage from crops grown on the farm under
the conditions of the model.
The requirement that all forage should be grown on the farm may be
reasonable for farms with low cow/land ratios. However, it was
desired that cow/land ratios in the model could be increased to
higher values than are usually encountered in the region, for the
purpose of comparing environmental parameters. It has been necessary
to compromise on the question of forage production, and this is
accomplished by allowing the purchase of up to 50% of the necessary
forage, if the model so desires. As will be discussed, this limit
may have a pronounced effect on the solution parameter values for the
model farm.
Capital -
In this model no constraint is placed on capital used in the farm
operation. It may be necessary to include such a constraint if the
model is expanded to include consideration of treatment plants for
manure disposal, or any handling system which is likely to involve
large capital commitments.
Legislative Controls -
Legislative controls on the activities of the farmer, relative to
manure disposal, are imposed on the modeling procedure during Step I
of the model. This means that the data prepared and presented to
Step II, the linear programming procedure, is determined, in part,
by the hypothetical controls which apply to the particular set of
solutions to be obtained.
Imposing the controls before the optimization step is a feature of
this model, and it is not intended to imply that this is the only way
in which these controls might be imposed. It might be advantageous,
for example, to set up the model so that the legislative controls
would be imposed on the linear programming procedure. This would
enable shadow prices to be computed for each control. The nature
of this type of study, however, is such that to do this would either
involve utilizing an even larger number of alternative activities,
or greater simplification of the manure disposal interactions. It
was decided that the approach taken in this model was most appropriate
for the type of study intended for this presentation.
168
-------
The hypothetical controls which were outlined have been used as a
guide for the application of controls to the farms used in this study.
Table 37 summarizes the controls which are used. Since this study
did not include any consideration of liquid manure handling, even
though the model was set up to be used with either liquid or solid
manure, many of the controls outlined in Table 36 are not included
in Table 37-
Step II
There are a number of assumptions which must be accepted when
linear programming is used. These include linearity of functions,
additivity and divisibility of activities, and the need for a finite
number of activities (33). These assumptions are all generally con-
sidered acceptable in agricultural problems, except for the assumption
of linearity (31). Linearity can be approximated, however, by the
acceptance of a number of simplifying assumptions with regard to
economies of scale in crop production. In this model, for example,
economies of scale in the use of crop growing and harvesting machinery
are not considered. Average values for the costs of these items, in
crop growing budget analyses for similar New York farms, are used
throughout the model. Non-linearity in dairy operations, however,
has been recognized and adjustments made to the costs associated with
milk production to reflect the economies of scale in housing and dairy
facilities.
While Heady and Candler (3l) point out that situations involving
economies of scale cannot be included in linear programming activities,
the assumptions which have been made regarding linearity of crop grow-
ing costs and returns do enable these activities to be approximated.
Thus it must be borne in mind when considering the solutions obtained
by the linear programming procedure that these economies of scale do
exist. Were the activities to be re-programmed with coefficients
adjusted to reflect the economies of scale of previous solution
values, some change in solution values might occur.
The linear programming procedure has been widely used in the past
for solving agricultural optimization problems (k, 51, 6U). Smith (65)
has used linear programming to study optimum allocation of cropping
practices for income maximization on a lew York dairy farm. Linear
programming has been used in this study in a similar way to that in
which it has been used by Smith (65).
DATA USED IN THIS STUDY
The data used in this study were chosen to approximate the real situa-
tion on New York dairy farms in the regions studied. The purpose of
169
-------
the study was one of comparison between regions and hypothetical con-
trols , The actual computed values of the parameters, presented should
not be used by any reader unless he has satisfied himself that the
data used are acceptable to him.
Location of Study Farms
It was desirable to have farms which were located in regions of New
York State which are densely populated with dairy cows. The regions
also had to represent a wide variation in soils and topography. Studies
of the distribution of dairy cows in lew York and of the Soil Survey
reports indicated two regions which satisfy these requirements. The
first was the townships of Cape Vincent, Clayton and Lyme of Western
Jefferson County, and the second was the townships of Augusta and
Vernon of Oneida County. The former location is also of interest
because of the possible relationship between agriculture and the
pollution occurring in the eastern bays of Lake Ontario and the
International section of the St. Lawrnence River (see for example
Cliff Carpenter, Ithaca Journal, Nov. 7, 1972.).
In very general terms, the Jefferson County region used in this study
is one of poor soils and flat slopes, and the Oneida County location
is one with highly productive soils and relatively steeper slopes.
Size of Farms
In each region the size of farm studied was made to conform as closely
as possible to the average size of the dairy farms of those townships
included in the region. The data for farm sizing was obtained from
the 196H Agricultural Census of Agriculture (9 and 10) and adjusted
by the percentage change during the previous five years to approximate
the size of farm for 1969-
Soils
Soil data was gathered from the published Soil Surveys of the counties
studied. The bulletin on Soils and Soil Associations of New York
by Cline (15), pamphlets on the Soils and Soil Associations of
Jefferson County and Oneida County (3U, 58), Bizzell's (7) bulletin
on Chemical Properties of New York Soils and Cline's (lli) Physical
and Chemical Properties of New York Soils were all used to estimate
essential soil data for use in this study. Soils very similar in
properties of interest to this study were grouped together to simplify
the computations made in the model.
Slopes -
Slopes of soils were approximated as the average slope occurring with
170
-------
each soil type providing that the range did not exceed 5$ in slope.
Where there was more variation than 5$, the slope was divided into
two or more equal sized areas each with an average slope covering the
range of slope for that area.
Crop data was obtained for 1969. Analysis of weather data indicated
that of the last three years for which data is available, 1969 had
the smallest variation from the 30-year mean for temperature and
precipitation (Table 38). Years prior to 1969 were not considered
because of the constant changes which are taking place in agricultur-
al technology which makes data from earlier years unreliable.
Crop yield data was estimated from the annual reports of the Cornell
University Agricultural Economics Cost Account Program (tl). The
highest yield level approximately corresponded to the average yields
of the top two farmers in the cost account program. Robinson and
Hope (60) have shown that the top three farmers in the Cost Account
Program have consistently received yields which were comparable to
the yields obtained by the Plant Breeding experiments in New York.
The intermediate level yields were approximately the same as the
average of the Cost Account Program, and the lowest level correspond-
ed to the average of the lowest three farmers in the program.
Table 38. STANDARD DEVIATION FROM 30-YEAR MEAN, 1969-1971,
TEMPERATURE AND PRECIPITATION OF WEEKLY AVERAGES
FOR GROWING SEASON AT SIX CENTRAL NEW YORK WEATHER
STATIONS. a
Year Temperature, °C Precipitation, cm
1969
1970
1971
16
15
15
1.31
1.86
1.50
a Data compiled from USDA Stat. Rep. Ser. and from data supplied
by B. Pack, Cornell Univ.
171
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Rotations
Some of the rotations were selected from the rotations which were
studied by Prof. Robert Musgrave at Cornell University in his long
term rotation study at the Aurora Research Farm (52). Others were
chosen as being representative of the rotations used in the regions
in which the farms being studied were located. In order that the
model would function correctly, it was necessary to approximate the
concept of "continuous" corn by using a rotation of five years of
corn followed by two years of alfalfa. The model is not capable in
its present form of handling an "open ended" rotation such as con-
tinuous corn, since the number of years that the crop is grown in
the rotation determines the fertilizer rate.
Fertility
Wherever possible, average fertilizer applications obtained for
each crop from the data of Kearl and Snyder (^1, h2) were used as
the intermediate fertilizer application needed to obtain average yields
on a soil of intermediate production capability. These fertilizer
levels, with adjustments for manure applications, were arbitrarily
increased by 50% and decreased by 50% to obtain the high and the low-
fertility levels respectively. These levels were then used, with the
available data on the productive capacity of each soil, to fit the soil,
yield and fertility level into the matrix of Figure 52 in such a way
as to best approximate the management level of the average Cost Account
Program farmer.
Published data conflict on the question of the possibility of main-
taining yields of corn in continuous culture even with annual incre-
ments of nitrogen fertilizer. Barber (3) shows that there is a
decline of approximately 3% per year in corn yields during the first
five years of continuous cropping with equal nitrogen fertilizer appli-
cations each year. Schrader et_ al_. (63), however, show that when
organic residue nitrogen is included in nitrogen applications, the
yields obtained in all years fall on a common nitrogen response curve.
This difference was resolved in this model by allowing a 2% decline
in yield with a 10% annual increase in nitrogen applications, where
no manure was applied. If manure was applied, no decline in yield
was assumed. This takes into account the approximate 2% increase
in yields of corn observed by McEachron et_ al_. (52) which was attri-
butable to the inclusion of manure in the nutrient applications.
Manure
Manure was assumed to be spread on field crops at a maximum rate
172
-------
of UU.8 Met. tons/ha (20 tons/acre) unless the controls for the soil
area involved were such that this application rate had to he reduced
Where manure was "dumped", it was assumed that this was done at the
maximum rate allowed. Where no restriction applied, the maximum
dumping rate was UU8 Met. tons/ha (200 tons/acre) which was somewhat
higher than the maximum dumping rate observed by the author while
visiting representative dairy farms in Hew York.
Estimating the rate of mineralization of manure nutrients is difficult,
as little information exists on this subject. Carbon-1^ studies have
been conducted by Jenkinson (38) on the decomposition of fresh plant
material. Jenkinson's data, and that of Bouldin and Lathwell (8) and
that found in the previously diseased experiment dealing with land
application, suggest that about 75-85% of manure organic matter can
be assumed to be eventually mineralized over a period of several years.
In this model it has been assumed that 50% is mineralized during the first
year, and another 20% during the second year. The remaining 30% is
assumed to represent that part of the organic matter which becomes
incorporated into the stable "humus" fraction of the soil. All of
the ammonia and inorganic nitrogen in the manure is assumed to be
available immediately for crop uptake, leaching, or loss as volati-
lized ammonia. The proportion which is lost by leaching and vola-
tilization will depend on the time of year that the manure is
spread, and has been estimated for each time period according to
the expected weather conditions during each time period. Warm day
conditions have been assumed to encourage volatilization and cool
wet conditions to encourage leaching. Ammonia volatilization
during six months of storage has been assumed to be equivalent to the
entire ammonia content of the manure when fresh from the barn, as
suggested by Weeks (7*0. Half of this was assumed to occur during
three months storage.
Manure is assumed to have a beneficial effect on soil aggregate stabil-
ity as has been shown by Zwerman et_ al_. (79). They also found a
direct relationship between aggregate stability and soil erosion loss,
which approximated a 30% reduction in soil loss at manure application
rates of six tons per acre. A 30% soil loss reduction has therefore
been included in this model for application rates of manure of 13-5
Met. tons/ha (6 tons/acre) or more.
Livestock
Livestock was restricted in this study to dairy cows and replacement
heifers. Management was assumed to be at a comparable level to that
of the average farmer participating in the Cornell Cost Account
Program (111). The most recent data which is available from this
program has been used for all factors of production of livestock.
173
-------
Precipitation
Precipitation data for the runoff prediction sub-model was obtained
from the United States Weather Bureau monthly report on the weather
of New York State. All Storms of 0.25 cm or more were grouped into
three groups: 0.25-1.25 cm, 1.25-2.5^ cm and greater than 2.5^ cm.
The average storm size within each group within the time period being
considered was used with the total number of storms during that
time period, in that storm group, as a simplification of the pre-
cipitation input data for the model. The records of the nearest
weather station to the region being studied was used as the source of
data. Averages were computed using the last five years of weather
records. Storms of less than 0.25 cm were assumed to result in no
runoff.
Selective Erosion Indices
It has been observed (6, 79) that the concentration of nutrients in
eroded material is usually higher than that in the soil from which
the sediment eroded. This has been referred to as an "enrichment
ratio". However, this term has been used in this study to describe
the increase in nutrients in the soil from a land-use activity. The
term "selective erosion index" has therefore been used to describe
the phenomenon described above (see Glossary). Data for selective
erosion indices for organic matter and phosphorus have been taken
from the study of Zwerman and Klausner (79).
RESULTS AID DISCUSSION
The regions, Western Jefferson County and Southwest Oneida County,
were chosen because of the large differences between them in soil
characteristics. These differences had a considerable effect on
the results of the optimizing procedure, as will be described below.
The solutions which are presented represent three conditions.
First there is the condition under which there are no restrictions
imposed on the solution by legislative action. It is assumed that
the farmer will consider only his profit maximization with no regard
for the external consequences of his activities. At Restriction
Level 1, it is assumed that no activity will violate the requirements
of Restriction Level 1 in Table 37. At Restriction Level 2, it is
assumed that the requirements of Restriction Level 2 of Table 37 will
not be violated.
It should be impressed upon the reader, at this point, that the controls
which were applied to the model did not include all of the factors con-
sidered in Table 36. The reasons for this is that Table 36 covered a
174
-------
number of situations which this study vas unable to include. Further
studies which do include these situations, specifically liquid manure
handling and storage, and manure treatment, are recommended.
Of the ten factors included in the original table of restrictions
(Table 36), only seven were seen to be relevant to the conditions
studied here. All of these seven were involved in the controls at
Restriction Level 2, which is considered to be representative of a
high degree of control over the farmer's decision making. At
Restriction Level 1, an intermediate degree of control, only five
of the original ten factors were operative.
The average farm size of the Western Jefferson County townships of
Lyme, Cape Vincent and Clayton, was found to be 121 ha (306 acres)
and that of Augusta and Vernon townships of Southwest Oneida County
was found to be 86 ha (212 acres). These farm sizes are used in the
model for the appropriate region. The herd size of dairy cows in
the model is ranged from 10 to 150 cows in 20 cow increments. The
wastes from the replacement heifers are included in the waste dis-
posal of any given herd size, so that the actual herd size generating
the wastes is approximately 25% greater than indicated on the curve.
However, since it is common for some replacements to be raised on a
New York dairy farm, it is not unreasonable to include this manure
with that of the dairy cows at any given herd size.
let Revenue
Figures 5^ and 55 represent estimates of the net revenue from each
farm. In the Jefferson County region, it can be seen that up to a
herd size of approximately 30 cows, there is little difference between
the net revenue regardless of the level of restriction which is imposed.
Beyond 30 cows, or 0.25 cows/ha, (0.1 cows per acre) the restrictions
imposed at level 2 force the farmer to grow more crop acreage than
he would otherwise do, and, since on these particular soils it appears
to be not profitable to grow crops for sale off the farm, the farmer's
net revenue falls. At 35 cows or 0.32 cows/ha (0.13 cow/acre), the
restrictions force the solution into an infeasible state as it becomes
impossible to dispose of the manure without violating the restrictions,
and the process of increasing herd size stops. At "Wo Restriction,"
and Restriction Level 1, there is a slight drop in "net revenue"^
between 50 and 90 cows which would appear to be caused by the slightly
higher costs associated with the use of a milking parlor which is
used at all herd sizes greater than 50 cows. Beyond a herd size of
90 cows, there is an almost linear increase in net revenue. If the
herd size was to be increased beyond 150 cows, net revenue could be
expected to continue to increase until the solution became infeasible
due to shortage of manure disposal land, with a probable reduction
175
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DOLLARS, THOUSANDS
—• — ro
D CJi o 0« O
• NO RESTRICTION
0 RESTRICT ION 1
• RESTRICTION 2
DINFEASIBILITY
_^/m
y^fc ^^ ^^ ,-^fc _ — fj| •' *^F
' 1 i 1 1 1 l
1
"0 .25 .50 .75 1.00 1.25 1.50 1.75
COWS/HA
Figure 5k. Net revenue (121 ha) - W. Jefferson County.
25r
CO
§ 20
CO
0 15
i-
| 10
_J 1
o 5*
o
°c
—
; ^'
p %
i
%
^^*
• NO RESTRICTION
©RESTRICTION 1
•RESTRICTION 2
OINFEASIBILITY
I i i
****
i
) .25 .50 .75 1.00 1.25 1.50 1.75
COWS/ HA
Figure 55- Net revenue (86 ha) - S. ¥. Oneida County.
176
-------
in net revenue at a herd size greater than 150 cows before the in-
feasible point is reached.
There is apparently no effect on net revenue from the imposition of
Restriction Level 1 on the Jefferson County farm, up to the maximum
herd density of 1.24 cows/ha or 150 cows (0,5 cows/ac).
When the herd size on the Oneida County farm is increased to 150
cows a slight reduction in net revenue occurs under Restriction Level
1. This occurs, however, at a higher density of cows per acre than
is reached in Jefferson County, because of the smaller farm size,
86 ha (212 acres) as compared to 121 ha (306 acres) in Jefferson
County.
When Restriction Level 2 is applied to Oneida County there is not the
noticeable drop in revenue before infeasibility occurs as is seen in
Jefferson County. The reason for this is because the soils on the
Oneida County farm appear to be such that it is possible to grow and
sell crops at a profit. Thus the effect of the regulations is simply
to prevent the herd size from being increased because of shortage of
manure spreading land. On the Jefferson County farm the same regu-
lations force unprofitable crop rotations to be used in order to have
a place for manure disposal, and so a rapid drop in net revenue is
observed before infeasibility is encountered.
The effect of the soils on net revenue is clearly demonstrated at the
zero cow level, where there is no revenue at all from the Jefferson
County farm, but the Oneida County farm yields a reasonable net
revenue from the sale off the farm of crops which can be produced at
a profit.
Referring to Figure 55, it can be seen that where there are no cows,
Restriction Level 2 actually increases net revenue compared to the
situation where no restriction applies. The explanation for this is
that Restriction Level 2 forces the fertilizer application rate to a
level which is not much higher than the uptake of nutrients by the
crop. The saving in the cost of fertilizers is reflected in the
increased net revenue from the farm operation.
Manure Unutilized or "Dumped"
Figures 56 and 57 show the effect of the restrictions on the amount
of manure which is disposed of by dumping onto unused land.
Restriction Level 2 prohibits all dumping, so that all values of
dumped manure are zero. At the Jefferson County location, there
is no increase in the amount of manure dumped per cow, as the herd
size increases, at Restriction Level 1 and when there is no re-
177
-------
MANURE PRODUCTION, %
ro 01 -4 o
^o 01 o 01 o
• NO RESTRICTION
ORESTRICTION 1
• RESTRICTION 2
DINFEASIBILITY
**
0 .25 .50 .75 1.0? 1.25* 1.50 1.75
COWS/HA
Figure 57- Amount of manure "dumped" - S. W. Oneida County.
178
-------
striction. The amount is approximately 30$ of the total manure
production (also shown in the figures). Had the model required
more than 50$ of the forage requirement of the herd to be home-
grown, it is likely that even less manure would have been dumped
as there would have been more crop acreage on which to utilize the
manure.
On the Oneida County farm, there is very little dumping of manure
until a 100 cow, or 1.2^4 cows/ha (0.5 cows per acre) herd size is
reached. The large acreage of crops has a large requirement for
nutrients and the manure is used to supply as much of this require-
ment as possible. Restriction Level 1 causes the dumping process to
start at a slightly lower herd size than when no restriction applies,
due to the effects of this restriction on reducing the amount of
cropped land on which manure may be spread.
It is of interest to note that at no time did the optimum combination
of activities, as selected by the linear programming procedure,
require the dumping of all the manure produced. Since any bias in
favor of manure spreading in this model has been deliberately avoided,
it must be concluded that the concept, sometimes advocated, of maximum
profits being obtained only when all crop nutrient requirements are
met with fertilizers, and where all manure is dumped, is probably
quite false for New York conditions.
Figures 58 through 63 show the effect of the regulations on the
cropping practices on the two farms. Again, it can be seen that at
the Jefferson County location, there was no difference between
Restriction Level 1 and "No Restriction," Alfalfa, corn and oats
are interdependent because of the dominance of the corn-oats-
alfalfa-alfalfa rotation in the model for this farm. At Restriction
Level 2, in Jefferson County, the relationship between these three
crops changes. This is found to be the result of a change in the
rotations under this restriction level. A corn-oats-grass-grass-
grass rotation was introduced because, though less profitable than
the other rotations, it made available an area of land for manure
spreading which the others did not. The grass in this model was con-
sidered a suitable crop to be spread with manure, while the alfalfa
was not - consistent with popular assumptions.
In the Oneida County location, more rotations were included in the
solutions. The most profitable rotation in this area is the model's
nearest approximation to continuous corn - five years of corn and
two years of alfalfa. However, this rotation is too restrictive in
terms of seasonal availability of land for manure spreading, parti-
cularly in the summer, so that as the herd size increases a rotation
179
-------
80h
• NO RESTRICTION
ORESTRICTION I
• RESTRICTION 2
DINFEASIBILITY
a60
2
<
-1 40
Q_
O
cr
0 20
S.W. ONE I DA COUNTY
D
J I
W. JEFFERSON COUNTY
I
.25 .50 .75 1.00 1.25 1.50 1.75
COWS/HA
Figure 58. Corn grown as percent of cropped land - both
counties.
g 60
• NO RESTRICTION
ORESTRICTION I
• RESTRICTION 2
DINFEASIBILITY
w- JEFFERSON COUNTY
S.W. ONEIDA COUNTY
'8:
0
.25 .50 .75 1.00 1.25 1.50
COWS /HA
••
•o
.75
Figure 59- Alfalfa grown as percent of cropped land
both counties.
180
-------
25-
Q
< 15
Q.
§10
CJ
W.
^
COUNTY
Figure
• NO RESTRICTION
ORESTRICTION I
•RESTRICTION 2
PINFEASIBILITY
S.W. ONE IDA COUNTY
JL
.25 .50
.75 1.00 1.25
COWS/ HA
1.50 1.75
Oats grown as percentage of cropped land -
both counties.
,-15-
Q.
O
CL
10
Figure 6l,
•NO RESTRICTION
ORESTRICTION I
• RESTRICTION 2
niNFEASIBILITY
w. ONEIDA COUNTY
- JEFFERSON COUNTY
ITYSfc
.50
.75 LOO 1.25
COWS / HA
1.50 1.75
Wheat grown as percent of cropped land
both counties.
181
-------
of corn-oats-wheat-alfalfa-alfalfa is substituted for the five years
of corn and two years of alfalfa. At Restriction Level 1 there is
no change from "No Restriction" until a herd size of 130 covs is
reached, when an increase in land set aside for manure dumping is
offset "by a reduction in alfalfa and wheat acreages;
At Restriction Level 2 on the Oneida County farm, corn and alfalfa
acreages drop as herd size increases beyond 10 cows. This reduction
in acreage of corn and alfalfa is matched by a rapid increase in
grass, and a smaller increase in oats and wheat. This results from
the substitution of a corn-oats-grass-grass-grass and a corn-oats-
wheat-alfalfa-alfalfa rotation for the five years of corn and two
years of alfalfa. Again, as with the Jefferson County farm, the
reason for this substitution is the need for crops which will
accept manure at all seasons of the year except winter, since no
dumping or manure is permitted at this level of restriction, and
manure has to be stored over winter.
Figure 63 shows the changes which occur in the percentage of corn
which is grown for silage instead of grain. These changes affect soil
loss and runoff and will be referred to later. All corn at the
Jefferson County location is grown for silage above a herd size of 50
cows. The reason for the changes which occur is the need to meet the
home-grown forage requirement of the herd.
Runoff
Estimates of the runoff from the two farms are presented in Figures
6k and 65. The Oneida County farm has slightly more runoff at low
cow/land ratios because of the greater acreage of cropland. However,
there is very little effect on the runoff either from increasing herd
size or from imposing restrictions. The reason for this is that the
principal variable in runoff is the cultivated land factor, which is
seen to vary little throughout the range of solutions in this location.
In Jefferson County, however, there is a continuous increase in
runoff as herd size increases due to the increasing amount of cropped
land.
In Jefferson County, the runoff is increased by the imposition of
Restriction Level 2. This follows as a result of the increase in
cropped land which is necessary for manure disposal under the con-
ditions of this restriction. Thus, it is seen that in a situation
where crop production is generally unprofitable, as for example
on poor soils such as those encountered in Western Jefferson County,
a restriction requiring that manure be spread only where uptake of
nutrients is possible, is likely to increase expected runoff. The
182
-------
~ 60
-1 40
Q_
o
oc.
0 20
W. JEFFERSON COUNTY
mm
• NO RESTRICTION
©RESTRICTION I
• RESTRICTION 2
DINFEASIBILITY
S.W. ONE I DA COUNTY
Figure 62.
.25 .50 .75 1.00 1.25 1.50
COWS / HA
Grass grown as percent of cropped land -
both counties.
1.75
100
75
UJ
g 50
25-
o
W. JEFFERSON COUNTY
—«—c»—•—m—« 9=
• NO RESTRICTION
O RESTRICT I ON I
• RESTRICTION 2
aiNFEASIBILITY
S.W. ONE I DA COUNTY
i i _ I _ I _ I
L
.25 .50
.75 1.00 1.25 1.50
COWS / HA
1.75
Figure 63-
Corn silage grown as percent of corn acr
both counties.
183
-------
o
§2
cc
Q
• NO RESTRICTION
ORESTRICTION I
• RESTRICTION 2
DINFEASIBILITY
'0 .25 .50 .75 1.00 1.25 1.50 1.75
COWS/HA
Figure 6k. Runoff as percent of rainfall - W. Jefferson
County.
_J
_J
< °r
z i-c
rf ~
<
cr
ii.
o
o
LL.
U_
O
Z
Figure 65-
1 1 1
• NO RESTRICTION
ORESTRICTION 1
• RESTRICTION 2
DINFEASIBILITY
1 1 1
I
.25 .50 .75 1.00 1.25 1.50
COWS/HA
1.75
Runoff as percent of rainfall - S. W. Oneida
County.
184
-------
reason for this Is the need for more soil to be cultivated than vould
be the case without the restriction.
Soil Loss
Two large differences in the expected soil loss from the two farms
are evident from Figures 66 and 67. One difference is in the mag-
nitude of the losses. The steeper slopes, and more erodible soils
on the Oneida County farm, coupled with the large area of cultivated
crops, lead to high soil losses compared with the Jefferson County
farm. The other difference is in the slope of the curves, which
show that in Jefferson County soil loss increases with increasing
herd size. It can also be seen that Restriction Level 2, on the
poor soil of Jefferson County, actually increases soil loss, which
would appear to defeat the object of the imposition of this restric-
tion.
The Oneida County soil loss tends to decrease with increasing herd
size, because of the greater amount of manure spread on the culti-
vated soil areas, with a consequent drop in the erodibility of the
soil as prescribed by the model. Restriction levels in Oneida
County appear to have little effect on soil loss. The variability
seen in the soil loss curves for "No Restriction" and Restriction
Level 1 in Oneida County is misleading. It results from the fact
that it is possible to arrive at two solutions to the maximizing
procedure which both result in the same maximum net revenue, but
which have different combinations of crops and soils. Although
the model requires every year of each rotation to be represented
on all soil areas used by that rotation, it is possible to select
different soils for different rotations while producing the same
economic returns. This results in different soil loss figures for
two situations which might be identical in every other respect.
Attaching a cost to farming sloping soils alone will not prevent this
problem, as soils on the same slope may have different erodibilities.
Only by placing an economic value on soil loss, thus forcing soil
loss to be included in the objective function of the maximizing pro-
cedure, will this situation be avoided. However, it is almost im-
possible at the present time to place a meaningful value on soil loss
in a model of this type. Any value which was used would also be
unlikely to reflect the attitude of the farmer in his decision making,
as farmers seldom attempt to place any direct economic value on soil
loss. It was therefore decided to allow the computer to make activity
selections without regard to soil loss, and to accept, as representa-
tive of actual conditions, any variability in parameter values which
resulted from this decision.
185
-------
1.6
1.2
N.
g .8
H .4
/>
- (P
X
<9
M /
(•~ i i i
°0 .25 .50 .75
• NO RESTRICTION
ORESTRICTION 1
• RESTRICTION 2
niNFEASIBILITY
i i i
1.00 1.25 1.50
i
1.75
COWS /HA
Figure 66. Soil loss - W. Jefferson County.
• NO RESTRICTION
ORESTRICTION I
• RESTRICTION 2
° INFEASIBILITY
i
i
25 .50
.75 1.00 1.25 1.50
COWS / HA
1.75
Figure 67- Soil loss - S. W. Oneida County.
186
-------
The increase in soil loss at the high cow numbers in Oneida County
appears to be the result of rotation changes in order to meet feed
requirements. The corn crop, particularly corn grown for silage,
has the highest overall soil loss rate of all the crops considered
by the model, and the percentage of corn grown for silage was seen
to increase with herd size on the Oneida County farm.
Total Potential Uitrogen Loss
The total potential nitrogen loss is that quantity of nitrogen which
can be expected to be lost either in runoff, sediment or seepage,
or volatilized as either ammonia (including storage loss) or as nitrogen
gas from denitrification.
It can be seen from Figures 68 and 69 that the total potential nitrogen
loss for Restriction Level 1, and where no restriction applies, closely
follows the curve for soil loss (see Figures 66 and 67). At Restric-
tion Level 2, however, this total loss of nitrogen is greatly reduced
in both the regions studied. The reason for this is the high degree
of control which this restriction level exerts over the amount of
nitrogen which is applied to the soil. Thus the regulation preventing
the application of more nitrogen than is needed by the crop, appears
to be successful in having a positive effect on nitrogen losses in
both counties. However, as will be seen later, all the individual
components of this total potential nitrogen loss are not necessarily
also reduced by Restriction Level 2.
Runoff Losses of Soluble Nitrogen
Runoff losses of soluble nitrogen are shown by Figures TO and 71
to follow the same trends as the losses of runoff water (see
Figures 6U and 65). However the increase in runoff which is seen,
in Jefferson County, to result from the application of Restriction
Level 2, does not lead to the same degree of increase in the loss of
soluble nitrogen in the runoff water. Thus Restriction Level 2 is
simultaneously increasing runoff and decreasing the amount of
nitrogen in the runoff water. The net result is a general reduction
in soluble nitrogen losses compared to that which is found when no
restrictions are applied, or when Restriction Level 1 is imposed.
In Oneida County, Figure 65 shows that there is little change in
runoff quantities as a result of imposing the restrictions. However,
the effect of Restriction Level 2 is to reduce the concentration of
nitrogen in the runoff, as is the case in Jefferson County, so that
the runoff loss of nitrogen is actually reduced by the set of re-
strictions at Level 2.
187
-------
100-
O>
LJ
o
75-
50-
oc 25-
Ol
1
• NO RESTRICTION
O RESTRICT I ON I
"RESTRICTION 2
DINFEASIBILITY
1
i
i
10 .25 .50 75 1.00 1.25 1.50 1.75
COWS/HA
Figure 68. Total potential nitrogen loss - W. Jefferson County.
O
-C
/
• NO RESTRICTION
©RESTRICTION I
"RESTRICTION 2
OINFEASIBILITY
°0 .25 .50 .75 1.00 1.25 1.50 175
COWS / HA
Figure 69. Total potential nitrogen loss - S. W. Oneida County
188
-------
o
-C
vs
01
NITROGEN,
2.4
2.0
1.6
1.2
.8
a
.4
0
-
- /
x§x
X*
8=8 »NO RESTRICTION
OX 0 RESTRICTION 1
-.| BA-D "RESTRICTION 2
^ DINFEASIBILITY
1 I i i i
1 L_
0 .25 .50 .75 1.00 1.25 1.50 1.75
COWS/HA
Figure 70. Soluble nitrogen loss in runoff - W. Jefferson County.
O
-C
o>
ft
"Z.
LU
0
o
a:
•MB
z
2.0
l.6a
1.2
i
.8
r^« ^/
^\^y «NO RESTRICTION
x ' ORESTRICTION 1
_>.__ "RESTRICTION 2
*-n aiNFEASIBILITY
Xf i i i i i i
•^
1 <
COWS/HA
Figure 71. Soluble nitrogen in runoff - S. W. Oneida County.
189
-------
Runoff Losses of Particulate Nitrogen
Particulate losses of nitrogen in eroded soil carried by runoff,
are presented in Figures 72 and 73. Predictably, these losses are
closely related to soil loss. Unlike soluble nitrogen, there is no
great reduction in particulate nitrogen when Restriction Level 2 is
applied. This implies that the restrictions are more effective in
controlling soluble nitrogen loss. This can be explained by con-
sidering the effect of the restriction on the model as it relates
to these losses. The total quantity of nitrogen in the soil, both
organic and inorganic, is large, and thus any practice which changes
the amount of total nitrogen in the soil must make a large magni-
tude of change in order to have a significant effect on total soil
nitrogen. However, the amount of soluble nitrogen in the soil at
any one time is relatively small, so that a change in practice
affecting mainly the soluble fraction of the soil nitrogen, does
not have to be great in order to have a significant effect on the
total soluble nitrogen.
Thus it is seen that particulate nitrogen is hardly reduced by
Restriction Level 2, whereas soluble nitrogen is considerably reduced
by this restriction. The reason for this is that eroded soil material
carries all forms of soil nitrogen with it, while runoff losses of
soluble nitrogen are only affected by the soluble nitrogen in the
soil.
Percolation and Denitrification Losses of Nitrogen
The reason for combining the percolation losses of nitrogen together
with denitrification as one loss, is because there is no effective way
to separate them. The model calculates this combined value by
difference. To separate the denitrification loss from that quantity
of nitrogen which must be assumed to pass through the soil into the
ground water, is almost impossible at this time.
It is evident from Figures 7^ and 75 that the effect of Restriction
Level 2 on the combined percolation and denitrification losses of
nitrogen is pronounced in both regions studied by the model. In
Jefferson County, Restriction Level 1 had no effect compared with the
unrestricted solution. In Oneida County, there is an apparent
increase in these combined losses when Restriction Level 1 is applied,
but the variability in the soil losses makes it impossible to
determine the significance of this apparent increase.
Particulate Phosphorus Loss
As was discussed, the losses of soluble phosphorus in runoff and
190
-------
z
LiJ
8 2
-------
o 50
-C
V.
zf
LJ
0 OR
O 25
CE
'
a
y/"
y
jf • NO RES
X^ ORESTRI
- /* "RESTRI
/ n INFEAS
9
nl 1 1 1
»
TRICTION
CTION 1
CTION 2
BILITY
I I 1
COWS / HA
Figure 74. Nitrogen loss by percolation and denitrification -
W. Jefferson County.
.o
-•
• NO RESTRICTION
O RESTRICT!ON I
• RESTRICTION 2
a INFEASIBILITY
Figure
0 .25 .50 .75 1.00 1.25 1.50 1.75
COWS/ HA
Nitrogen loss by percolation and denitrification -
S. W. Oneida County.
192
-------
seepage water are both unpredictable and essentially small. This
does not mean that they are not important - and it may eventually be
shown that soluble phosphorus (from all sources, not just agricul-
ture) rather than soluble nitrogen, is the principal cause of eutro-
phication in receiving waters, even if only in very low concentrations
However, to include estimates of soluble phosphorus losses in this
model at this time would only serve to impair the credibility of the
whole model. Further research may indicate more reliable methods
of predicting soluble phosphorus movement than are currently avail-
able.
Particulate phosphorus losses have been estimated and these are
presented in Figures 76 and 77- These losses follow very closely
the trends seen in the soil loss curves of Figures 66 and 67. As
has already been discussed relative to nitrogen losses, the reason
for the small effect of the restrictions on particulate losses is
the relatively small influence which changes in nutrient applica-
tions have on the total amount of the nutrient in the soil. This
applies to phosphorus as well as nitrogen, and so the curves for
particulate phosphorus are also very similar to those of soil loss.
Other Relevant Parameters
There are many other factors which may be studied with the use
of this model. Only those of interest to the particular subjects
of legislation and agronomic and manure management practices have
been presented.
GENERAL DISCUSSION
The assumptions of the physical nature of the farm have an effect
of the two locations. The two hypothetical farms were of different
sizes, but the distances used for zone classification in the hypo-
thetical legislation were the same for both farms. This means that
the proportion of the land area of each farm, which is included in
the controlled manure spreading zones, is different. This difference
contributes to the fact that the Jefferson County farm became infea-
sible under Restriction Level 2 at 35 cows, while the Oneida County
farm became infeasible at only 23 cows.
Some of the other assumptions and simplifications used in this study
require further discussion in relation to the results which have
been presented. The assumption dealing with linearity of crop
growing and machinery costs, for example, is an assumption which
probably results in the costs per unit area, at low acreages^being
assumed to be lower than they might be in reality. Thus the "net
revenue" observed at low herd sizes in the Jefferson County location
193
-------
PHOSPHORUS, kg /ha
2 f\3 *
•
o
•
a
a d
>&=•*£ or- v^^
fiii
NO RESTRICTION
RESTRICTION 1
RESTRICTION 2
INFEASIBILITY
r-«"-
1 1 1
1
.25 .50 .75 1.00 1.25 1.50 i.75
COWS/HA
Figure 76. Particulate phosphorus loss - W. Jefferson County.
oi
• NO RESTRICTION
O RESTRICT I ON I
• RESTRICTION 2
n INFEASIBILITY
.O
'0 .25 .50 .75 1.00 1.25 1.50 1.75
COWS/HA
Figure 77- Particulate phosphorus loss - S. W. Oneida County.
194
-------
is probably slightly overestimated. Similarly, at the largest
herd sizes in Jefferson County, the "net revenue" may be slightly
underestimated as a result of this assumption. The crop acreages
in the Oneida County location were seen to vary less than in the
Jefferson County location, and the assumption of linearity of crop
growing costs is unlikely to have any pronounced effect.
Another simplification which affects the results is that associated
with the loss of ammonia nitrogen volatilized from storage. The
effect of this simplification is only applicable to the results
under Restriction Level 2. It has the effect of reducing the herd
size which can be reached before infeasibility occurs, as nitro-
gen disposal is the limiting factor in manure disposal at this
restriction level.
The reason for this is that the manure application rates are calcu-
lated based on the nitrogen available to crops, e.g. after ammonia
volatilization. The simplification used here assumes that a portion
of the winter manure ammonia is available to crops, depending on the
time at which it is spread, whereas it is actually volatilized from
storage and is not available. Thus the summer and fall application
rates used are slightly lower than would be strictly allowable under
Restriction Level 2. It is estimated that this simplification had no
effect on the Jefferson County farm, as almost all stored manure was
spread in the spring at the infeasibility point. On the Oneida County
farm, all stored manure was spread in the fall, and a herd size
reduction of about k% (or 0.9 cows) occurred at infeasibility. While
this simplification has been used here without any great effect on
the results, it is probable that some alternative method of handling
ammonia volatilization before manure is spread should be devised if
any treatment or other high-ammonia-loss handling method was to be
included in the study.
Another simplification which may effect the results is that of a
single management level. It is probable that the results on the
Jefferson County farm would be more similar to those of the Oneida
County farm if the level of management was assumed to be higher in
Jefferson County. It would be generally true to state that the soils
of Western Jefferson County need better management than the more
productive soils. If given this better management, they may be almost
as productive as those soils in Oneida County which produce high
yields without high levels of management capability.
It is difficult to determine, with any degree of certainty, which^
of the legislative controls is most limiting, at any given herd size,
in terms of the farmer's ability to increase his income. The reason
for this difficulty is partly due to the nature of the controls, and
partly due to the nature of the model. For example, it will be seen
195
-------
from Table 37 that, at Restriction Level 2, land is being zoned for
"no manure applications" by both the distance from surface water
control, and the distance from dwellings and public access control.
Thus it is impossible to determine which of these two controls is
limiting. Similarly, it can be seen that since the manure applica-
tion rate control (control parameter l) reduces the quantity of manure
which can be spread on that land which is available for disposal, there
is a consequent need for more "disposal" land at the same herd size.
However, more land on which spreading may be done may not be avail-
able because of the distance from water and public access controls.
Thus again it can be seen that it is impossible to determine which
of these controls is limiting the fanner's income the most. The
control in Table 37 which requires certain minimum land areas to be
owned or controlled per animal kept on the farm was, in all instances
in this study, of no effect. Herd densities never reached the control
limit, either because the herd size never became large enough, as
in the case of the control of Restriction Level 1, or because in—
feasibility occurred before the herd size limit was reached, as was
the case at Restriction Level 2.
In both locations it was seen that there was very little change in
"net revenue" when Restriction Level 1 was imposed compared to the
situation where no restriction applied. It was also evident that the
expected losses of nutrients to the environment were not affected by
Restriction Level 1 either. However, it should not be overlooked
that there were a number of immeasurable benefits from Restriction
Level 1, such as the elimination of manure spreading within certain
limits of dwellings and public roads. It would appear, then, that
these benefits were gained at very little cost to the farmer, within
most of the range of herd sizes used in this study. At the last two
herd size increments in the Oneida County location, a drop in
revenue was observed at Restriction Level 1. Thus it is likely that
on the Jefferson County farm the imposition of Restriction Level 1
will reduce the farmer's potential income at some herd size greater
than 150 cows.
At Restriction Level 2 the requirement that the storage should be
located at least 151 m (500 ft) from the barn and farm dwellings
was met without affecting the net revenue. This was because there
was no land less than 151 m (500 ft) from the barn on which spreading
was permitted so that the transportation cost to a zone at least 151 m
(500 ft) from the barn was necessary with or without this requirement.
The shadow prices for the different soil type areas indicate that
land which cannot be used for manure spreading would add nothing to
revenue if increased on the Jefferson County farm at any restriction
level. On the Oneida County farm this land is worth about $U2-8U per
196
-------
hectare in terms of increase in revenue if there was a one acre
increase in the most productive soil, depending on herd size. At
the point where the solutions become infeasible at Restriction Level
2, land on which manure can be spread has its highest shadow price.
The shadow prices indicate that the land in the second distance zone
from surface water, that on which manure spreading on sod crops is
allowed, is less valuable than the unrestricted land. However, the
difference between the shadow prices of this land and the unrestricted
or the completely restricted land indicates that, except at the point
of infeasibility, it would add more to the revenue of the farm to
transfer one hectare from partially restricted (spreading allowed on
sod) to unrestricted, than to transfer one hectare of completely
restricted soil to the partially restricted zone. Thus it can be
said that the difference between allowing spreading of manure on
sod, and allowing no spreading at all is less than the difference
between allowing spreading on any crop and allowing spreading only on
sod crops. This is true of both locations prior to infeasibility.
The situation is reversed at the point of infeasibility, because
at this point, the ability to spread any manure at all becomes of
great importance to the solution.
It must be considered, then, when deciding on the benefit of pro-
hibiting manure spreading within a certain distance of surface
water, that any environmental benefit which results would probably
cost the operator of the farm more, in terms of lost revenue, than
prohibiting manure spreading on all crops other than sod. However,
it should be remembered, when deciding the boundaries between these
two restrictions and the unrestricted land, that a change in the
boundary between "no spreading" and spreading only on sod crops, will
probably have a lesser effect on farm income than a similar change in
the boundary between the unrestricted zone and that in which manure
spreading is allowed only on sod, providing that the farm is not at
the point of infeasibility, which is unlikely.
197
-------
SECTION VI
A COMPARISON OF (l) CONVENTIONAL AND (ll) IMPROVED
DAIRY WASTE MANAGEMENT ON TWO HYPOTHETICAL DAIRY FARMS
Private enterprise has given little or only limited considerations
to the environment. During the past five or six years, EPA and other
agencies have made an effort to point out the need for protecting
and improving our environment. It is said by many that this pro-
tection and improvement of the environment must be done at the
expense of the individual or society. It does not necessarily
follow that society or the individual—in our case a dairy farmer—
must find it unprofitable to carry out such operations.
The above statement of a concept has been brought about because of
the fact that the public understanding of energy conservation and
ecologically sound waste management is changing. There is a new
appreciation of the value of all organic waste as fertilizer. There
is a new addition to farm management programs which has only recently
become widespread. Prior to the present time, it was comparatively
easy for a farmer to supplement his plant nutrient needs by the
purchase of commercial fertilizer at a very low price. This price
was in comparison to the relative cost of other materials involved
in the farming operation. (See Table 39).
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Table 39- COMPARATIVE PRICES PER KILOGRAM FOR FERTILIZER NUTRIENTS
DELIVERED AT THE FARM. 1970 VERSUS 1975 (PROJECTED (80))
Year N p o K20
Jan. 1970 .11 .17 .09
Jan. 1975 .73 .37 -22
The national impact of this economic circumstance was that animal
manures on the farm were regarded as a major disposal problem. This
problem inferred that there should be no interference with the envir-
onment and that, in fact, public money or private money would have
to be spent to make sure that the animal manures would be properly
handled to insure no environmental damage. The broader energy pic-
ture has become apparent only within the last year. The fact that
it takes a very considerable amount of energy to produce fertilizer
nutrients has up until now not been widely appreciated. The costs
of nitrogen in terms of energy can be realized when it is remembered
that one kilogram of synthetic nitrogen is the equivalent of approx-
imately two kilograms of diesel fuel in terms of energy (82).
Nitrogen has been produced synthetically by manufacturing anhydrous
ammonia under the catalytic process of uniting hydrogen and nitro-
gen using the energy of natural gas. With the shortages and in-
creased price of natural gas, the price of nitrogen has necessarily
been increasing. (See Table 39) Based on nutrients as fertilizer,
one metric ton of free stall dairy manure was worth $1.18 in 1970 and
is projected to be worth $1*.67 in 1975-
GENERAL MANAGEMENT DECISIONS ON NUTRIENT RECYCLING ON THE DAIRY FARM
In addition to growing the feed for the dairy animals, each dairy
farm needs to have a proper soil balance of mineral nutrients. This
is necessary to maintain high crop yields on the dairy farm. This_
presentation is given to illustrate the nutrient recycling on a dairy
farm. It is schematic for those portions of the dairy industry where
experimental data from this project has not been collected. We have
used representative information from the literature in order to make
the character of the decisions more realistic. A one-hundred_cow
dairy is assumed. This size of dairy is maintained by Approximately
two-thirds of a cow per animal in calves, young stock, and heifers in
order to maintain the milking line of cows. For sake of convenience,
we will say that there will be l60 animal units in our working dairy.
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All -practical options considered are those already utilized in New
York State. A farm of approximately jA6 hectares of tillable land
is a convenient size to consider for this operation. Additional
hectares of cropland and/or pasture land are also possible. Such
land additions would depend upon the permanency of the program. It
is assumed that there is a (l) conventionally managed, and (ll)
"improved" managed dairy farm. They are identical in numbers and
kinds of animals and also in land resources. Difference between
(l) and (II) are developed as a result of land resource management,
cropping practice, and manure management.
Each milking cow or dry cow or heifer which make up the total popu-
lation of 160 animal units will require a necessary amount of feed per
animal unit. This is six metric tons of hay equivalent per animal
unit (8M- While this six metric tons of hay equivalent per animal
unit is adequate for calves, heifers, and dry cows, milking cows will
require 1270 to 1525 kilograms of corn plus concentrate.
First, the management conditions for (ll) improved management will be
discussed. One can make the assumption that the animals will be fed
for their total six metric tons of hay equivalent three metric tons
of dry matter in the form of corn silage and three metric tons of
dry matter in the form of haylage . They will be fed grain in the form
of 1300 to 1500 kilograms of grain. In addition, a protein supple-
ment will be purchased. On l60 animal units one then arrives at a
total of 1^6 hectares of land to produce the total corn and alfalfa
needed to sustain the cows. In addition, 18 hectares of wheat will
be grown. This wheat will yield approximately ho bushels per acre.
It will also produce U.5 metric tons of straw per hectare. One is
obliged in order to maintain this ratio of crop use on the land to
leave the alfalfa intact for three years and to grow corn for four
years in the rotation. Each year 18 hectares would be taken out of
alfalfa and plowed for corn. Each year 18 hectares of corn land
would be seeded to alfalfa. Also 18 hectares of corn land will be
seeded to wheat. (See Table
In order to maintain the soil structure to maximuze the inputs of
organic matter and to minimize the energy inputs, the following
system of management with respect to corn would be utilized. During
the first year after alfalfa, the corn would be grown in a no-till
situation. After wheat, corn will also be grown in a no-till situa-
tion. Red clover having been seeded in the wheat. Assuming that the
farm was in all alfalfa, the first year would see no-till corn planted
on 73 hectares, of which, 36 hectares of corn would be harvested for
silage. Early varieties would be utilized both for silage and for
grain. It is assumed that the silage yield would approximate 16
metric tons per acre per year. It is further assumed that the grain
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Table Uo. SCHEMATIC REPRESENTATION OF CROP ROTATION FOR MAXIMIZING
SOIL STRUCTURE IMPROVEMENT AND DAIRY MANURE RECYCLING.
Year
197^
1975
1976
1977
1978
1979
1980
1981
Field Designation Number !
1
C
C
W
C
C
A
A
A
2
C
W
C
C
A
A
A
C
3
W
C
C
A
A
A
C
C
k
C
C
A
A
A
C
C
W
5
C
A
A
A
C
C
W
C
6
A
A
A
C
C
W
C
C
7
A
A
C
C
W
C
C
A
8
A
C
C
W
C
C
A
A
a Each field is 18 hectares
C = corn; ¥ = wheat; A = alfalfa
corn yield would approximate 5000 kg/ha/yr. If desired, the fodder
from the grain corn may be removed and shredded and used for bedding
for the young stock. Winter wheat will be seeded after silage removal.
This will make wheat straw available for bedding as well. As soon
as the corn has been removed for grain, rye will be seeded directly
into the no-tilled plots. The corn for grain will be planted in the
second year after alfalfa and wheat. If the stover from the grain
harvest is not used for bedding it will be chopped and left on the
land and plowed down for wheat and alfalfa respectively. Wheat would
be seeded in the fall and alfalfa would be direct seeded in the spring.
Conventional Management
The exact practices that a "conventional" dairyman would use in crop
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production and soil management are not known. They could be deter-
mined on the basis of a survey. The information presented here is
based on observations in New York State.
In general, crop rotations are not rigorously followed. Areas close
to the dairy barn are usually planted to continuous corn. Wheat is
not generally grown. Alfalfa is planted at a greater distance from
the dairy barn. It is assumed that this alfalfa will remain in hay
until it is "run out." Bedding is generally not provided for in the
cropping program, but is obtained where possible.
Manure Management
The following presentation concerns the general situation and (ll)
improved management. The 100 milking cows will be housed in a free
stall "cold barn." The barn will be equipped with a delta scrapper
and a urine channel (U3, 83). This urine channel will make it pos-
sible to collect and store 290 metric tons of urine annually. This
urine will be used for side dress on 73 hectares of corn annually.
It will also be used to top dress wheat in the spring. Rates on
corn will be 3.36 metric tons of urine per hectare, 50 kg of N and
50 kg of KgO per hectare. Wheat will be top dressed at the rate of
2.2 tons/ha (3^ kg/ha of N). Approximately Il80 metric tons of
slurry manure will be generated during the year by the 100 milkers.
Eight hundred metric tons of this material will be hauled into
temporary especially constructed storages close to the fields where
it will be applied to 36 hectares of corn at the rate of 18 metric
tons per hectare immediately before spring plow down.
The wheat straw will be used to bed down calves, young stock, heifers,
and dry cows in a pen stable. These animals will compact and pre-
serve this manure. Eight hundred metric tons will be transported
immediately from the pen stable to the corn field immediately
before plow down.
The approximate 360 metric tons of slurry manure from the milkers not
needed for corn will be spread on the 18 hectares of wheat late in
the fall.
Conventional Handling -
The milkers will be housed in a "cold" free stall barn. Manure will
tractor scraped to a lip and spread daily on continuous corn land.
Calves, young stock, heifers, and dry cows will be bedded with as
little straw as possible. This manure will also be spread on corn.
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Environmental Benefits of Improved (ll) Over Conventional (l) Management
The research reported here shows in general that:
1. Well-maintained soil structure looses approximately only half
as many nutrients to the environment as poorly-maintained soil
structure. Conventional management (l) has 73 hectares of poorly-
managed corn in contrast to 73 of (ll) well-managed corn.
2. The lowest rate of nutrient losses were obtained from immediate
plow down in the reported research. This is being practised in
II. Storage is discussed in references h3 and 83.
Benefits to the Farmer of Improved (ll) Over Conventional (l) Practice
Improved management (ll) will very likely use a Logoon for milking
center waste (85). This may supply limited nutrients wasted under
(l). Both management systems will produce I960 metric tons of
manure. Using the 1975 values of Table 39, one arrives at $7,200 for
N, $1,756 for Pp05 and $2,l60 for K20. One can assume that improved
management saves 75 percent of N, 90 percent of P205 and 75 percent
of KpO. Similar values for conventional management would be
30 percent for N, 70 percent PgO^ and 30 percent for K20.
In terms of dollar value return on the manure, we would have
approximately $H,000 for conventional versus $9,000 for improved
management. If one uses the cost data of Jacobs and Casler (8l) for
conventional handling, one has a cost of $^2 per cow. If one uses
their cost per cow for a liquid system, one has a cost of $6U per
cow. It is assumed that the added costs of urine handling and low
cost outdoor storages would equal those of the liquid system. Thus
the cost per cow for 100 cows would be $22 more or $2200. Approxi-
mately $2500 would be saved each year on fertilizer costs. It is
assumed the calves, young stock, heifers, and dry cows would have
the same manure handling costs.
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SECTION VII
SUMMARY
The following is a summation of the research findings dealing with
the land application of manure and the results obtained from the
linear programming model.
Dairy manure disposal consisted of a single land application to field
plots during the winter, spring and summer at rates of 35» 100 and
200 metric tons/ha. Each time and rate of application appeared on
both a well managed soil (return of crop residues) and a poorly managed
soil (removal of crop residues). This plan made it possible to demon-
strate the influence of the past l6 years of soil management practice
and the present dairy manure treatments on nitrogen and phosphorus
losses from the land. Nutrient losses were measured for the three
rates of application in surface water effluent and in sediment but
only for the 35 and 200 t/ha rates for tile effluent.
Manure applications began with the winter treatment in February 1972.
January 1, 1972 was chosen as a starting point in the calculations of
annual losses of inorganic nitrogen and total soluble phosphorus in
surface water and tile effluent and total nitrogen, total phosphorus
in the sediment. The data presented are the results of all sample
producing runoff and drainage events as derived from natural rain-
fall. In one instance, a rainfall simulation (irrigation) study was
conducted on a single treatment in order to investigate nitrogen
and phosphorus losses with time during a drainage event.
Annual nutrient loss comparisons were made for 1972 and 1973.
Nutrient losses for entire 197^ have not been completed to date.
The 1972 calendar year in the northeastern United States was
extremely wet. Precipitation was 67% above 'normal.' A tropical
storm in June caused considerable rainfall and flood damage. Due to
an abnormally wet year, results presented for 1972 may be a somewhat
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atypical array of the nutrient losses that may be expected under a
more normal weather pattern. The data is extremely meaningful in
demonstrating the magnitude of nitrogen and phosphorus discharges
that can occur under adverse weather conditions. Annual precipita-
tion during 1973 was only 2 cm above 'normal' and nutrient losses
during this year may be more nearly typical of what can be expected.
ANNUAL NUTRIENT LOSSES
Surface runoff discharges of inorganic nitrogen and total soluble
phosphorus showed a marked difference, for all treatments, between
1972 and 1973. The average increase in 1972 over 1973 was 750$ and
3^0% for nitrogen and phosphorus, respectively. This clearly
indicated that weather conditions are the most influential variable
in studying nutrient losses. Regardless of the time and rate of
dairy manure applications, nutrient discharges were a direct function
of the intensity and duration of a climatological event.
With regard to annual nitrogen losses in surface runoff, the spring
application and subsequent plowdown of manure proved to be superior
over applications made in the winter or summer during a wet year
(1972). The winter application during the same year yielded the
greatest loss of nitrogen mainly due to the influence of a single
snow melt event. Differences among the timing of manure applica-
tions for a more 'normal' climatological year (1973) were insignifi-
cant. The intermediate rate of application (100 t/ha) resulted in
the greatest losses of nitrogen during both years. The 100 t/ha rate
treatments are not tile drained and tend to exist on the more erosive
plots, accounting for the greater discharges. Throughout the course
of the experiment, the lowest rate of application (35 t/ha) yielded
the lesser discharge of nitrogen in surface runoff. The highest rate
of application (200 t/ha) resulted in nearly twice the discharge of
nitrogen in comparison to the lowest rate during both 1972 and 1973.
Phosphorus discharges in surface runoff were similar to nitrogen
with regard to treatment effects. Annual losses of total soluble
phosphorus proved to be significantly greater for the winter applica-
tion during both years. Phosphorus losses resulting from the spring
and summer disposal periods were essentially identical. With refer-
ence to the rate of application and annual discharge of phosphorus,
the 35 t/ha application rate produced a significantly lower discharge
than the 100 and 200 t/ha treatments. The latter two rates of appli-
cation exhibited similar phosphorus losses in 1973, but during the
wet year of 1972, the 100 t/ha rate produced the greatest discharge,
for reasons previously explained for nitrogen.
A soil structure variable (good versus poor) proved to be very in-
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fluential. Well managed soils had significantly lower nitrogen
and phosphorus discharges in runoff especially during an abnormally
wet year in comparison to poorly managed soils. Well managed soils
(return of plant residues, e.g. corn for grain) were superior to
poorly managed soils (removal of plant residues, e.g. corn for silage)
because of improved soil structure. Improved soil structure enhances
infiltration and water transmission through the soil profile. In
both 1972 and 1973, surface runoff was twice as great on poorly
managed plots.
The addition or removal of plant organic residues (it has persisted
in these plots for the last 17 years) as it influences soil structure
may become erased in future years by the larger additions of organic
matter from manure. Even if this characteristic is masked by future
manure additions, the physical presence of a plant residue cover on
the soil surface after harvest, on the well managed plots, would aid
in the reduction of surface runoff.
Annual total nitrogen and total phosphorus losses in soil sediment,
similar to nutrient discharges in surface runoff, was highly variable
from year to year. Average nitrogen and phosphorus contents in
sediment were approximately 63% and k3% greater, respectively, in
1972 as compared to 1973, mainly associated with increased rainfall
and runoff in the former year. The timing of manure disposal showed
a very limited influence on nutrient discharges in sediment for both
years. Increasing increments of manure rates significantly increased
nitrogen and phosphorus losses during 1972, but the relationship did
not hold in 1973. In the latter year, the 100 t/ha rate had a
significantly higher discharge of nitrogen and phosphorus. The loss
of these two nutrients in both years was directly correlated to the
loss of organic matter in sediment.
Soil management exhibited a significant influence on sediment losses.
Plots that were poorly managed showed an approximate 250% and 360%
increase in nitrogen and phosphorus discharges, respectively, in
comparison to well managed soils.
In discussing runoff and sediment losses of nitrogen and phosphorus
on an annual basis, some inconsistency was evident, especially when
considering nutrient losses as affected by the rate of manure applica-
tion. The 100 t/ha rate appears to be the treatment that was out of
place when considering losses relative to 35 and 200 t/ha. This
inconsistency is evident for many reasons.
Much of the increase due to the 100 t/ha rate in surface runoff
during 1972 was due to an interruption in the disposal schedule
during the winter. Unlike the 35 and 200 t/ha treatments, the 100
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t/ha rate was delayed due to adverse weather, and was spread on
dense melting snow in February, a condition not condusive to
nutrient conservation, but none the less undoubtedly exists in
actual farming situations. This surface soil condition resulted
in unfavorable nutrient losses and raising upward the losses due
to the 100 t/ha rate and the winter application relative to the
other two rates of application. In addition to this condition,
the 100 t/ha treatments were not existent on tile drained plots
and although they were randomized, they tended to be associated
with the more poorly drained plots of the experiment. This
condition is reflected in the runoff and sediment losses relative
to the two other rates of application. This phenomena should not
be dismissed as too complex. Soil heterogenity is commonplace in
any watershed, and results of a given treatment under given clima-
tological references will vary with soil characteristics.
Annual tile discharges were studied for the three disposal periods for
two rates of application (35 and 200 t/ha). The quantity of nitrogen
and phosphorus in tile drainage was not a reliable indicator of the
quantity that will eventually find its way to the ground water
reservoir. Artificial internal drainage alters the natural pathways
of water and consequently nitrogen and phosphorus movement.
From a statistical viewpoint, taking into acocunt the variability of
annual quantities within replications, discharges of nitrogen and
phosphorus were not influenced by the timing or rate of manure appli-
cation, nor the soil management practice.
DELECTED RUNOFF EVENTS
The design of manure management schemes for an 'average' year, in
terms of climatic events is difficult to assess since an average
year exists in definition only. In the same sense, no two climatic
events will be the same nor will the antecedent conditions pertaining
to them be the same.
A series of selected runoff events were chosen to compare the rela-
tive behavior of manure treatments for a given climatological event.
This becomes meaningful since a good many of the independent influences
concerning nutrient discharges are acting similarly. Runoff events
were chosen on the basis of the type of climatological event and
to give a broad spectrum over seasons.
A snow melt event in February of 1972 served to illustrate the
necessity to avoid spreading of manure on melting snow. The 35
and 200 t/ha winter rates were applied on frozen soil void of
snow. The 100 t/ha rate was delayed due to a snow storm. Ten days
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later it was applied on melting snow. The data clearly indicated
that manure disposal during active thaw periods can result in ex-
tremely excessive nutrient losses and high nutrient concentrations.
However, low and high rates of application (35 and 200 t/ha) dis-
posed on frozen soil and then covered with snow before a thaw period
may result in acceptable losses especially at the lower rate of
application. As an example, the inorganic nitrogen loss from 100
t/ha was k6 kg/ha, and 1 and 8 kg/ha for the 35 and 200 t/ha rates,
respectively. The lower rate of application resulted in nitrogen
and phosphorus losses less than areas that received no manure at all
(plots that would receive the first application of manure in the
spring and summer). When the excessive losses from the 100 t/ha rate,
a function of the time of application during the winter and not the
rate per se, are accumulated over a period of time, this one runoff
event places the nutrient losses from 100 t/ha out of phase relative
to the 35 and 200 t/ha rate, and the winter application out of
phase relative to the spring and summer applications.
Hurricane Agnes in June 1972 caused considerable flooding and
damage to the eastern seaboard. The general behavior of nutrient
losses for this runoff event were quite erratic for the rate and
timing of manure application. The erratic behavior of these treat-
ments can be explained by the very important fact that once a soil
becomes saturated, imposed manure treatments no longer play an
important role on runoff. The quantity of runoff and sediment dis-
charge becomes a function of the infiltration rate, percolation rate,
slope, etc. for the various plots, or more broadly, for the heter-
ogeneous soils within a watershed.
An intense rainstorm in August of 1972 (6.U cm in one hour) was
classified as excessive according to U.S. Weather Bureau standards
with a probability of a 1 in 50 year occurrence. When this event
occurred, the corn crop was at maximum height and nearly fully
matured. With such a high intensity rainfall, one would expect
severe erosion. Runoff and sediment losses of nitrogen and phos-
phorus were from 1 to 2 orders of magnitude lower than both the
previous winters snowmelt event and the recent hurricane. The
presence of an almost complete canopy of vegetative material over
the soil surface was responsible for reducing rainfall impact,
protecting the soil against erosion.
Early winter rainfall (3.8 cm in December) almost one year since
the previous winter disposal and 8 and 7 months after the spring
and summer applications resulted in approximately twice the dis-
charge of these nutrients in runoff for the summer application,
in comparison to winter and spring applications. The exposure of
soluble nutrients on the soil surface (summer) versus the plowing
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down of manure (winter and spring) showed an influence at this later
date.
Late winter rainfall for two selected runoff events (mid-March and
early April 1973) served to illustrate the effects of residual nitrogen
and phosphorus. The winter application for 1973 had already been
applied. The second manure application cycle had not yet been applied
to the spring and summer plots. Manure had been applied approximately
12 and 9 months prior to these two runoff events for the spring and
summer application, respectively.
The discharge of nitrogen in surface runoff for winter applications
was equivalent or less than the discharges from previous spring and
summer applications. The residual nitrogen from prior applications
was great enough to approximate the losses incurred from a very
recent winter application. Nitrogen transformations from the organic
to the inorganic fractions is occurring continuously and can supply
an adequate amount of mobile inorganic nitrogen to runoff.
Phosphorus losses, on the other hand, displayed a higher discharge
in surface runoff for the winter application because of readily avail-
able soluble phosphorus. The residual effects of phosphorus from the
first cycle (spring and summer applications) was not as influential
as nitrogen in supplying soluble material in runoff. Future avail-
ability of insoluble phosphorus from manure, like nitrogen, is
provided by mineralization. Unlike inorganic nitrogen, soluble
phosphorus is not highly mobile and soil fixation can render much of
the soluble portion unavailable.
Sediment losses of nitrogen and phosphorus from these two runoff
events were not significantly different with regard to the rate or
timing of manure application.
A snowmelt event (December, 1973) accompanied by 1-2 cm of rainfall
on non-frozen soil was selected to further study nutrient losses during
the winter. On the whole, this runoff event accounted for only 5% of
the annual runoff and 3% of the annual soil loss. Nutrient losses
were inconsequential.
Runoff occurred two weeks prior to the beginning of the third winter's
manure application. Average nitrogen and phosphorus losses for both
runoff and sediment appeared to correlate to the lapsed time since
manure disposal (summer > spring > winter). Nitrogen and Phosphorus
losses in runoff ranged from 0.03 to 1.2 kg/ha and 0.0 to 0.07 kg/ha,
respectively. Sediment losses of these two nutrients were less than
0.07 kg/ha.
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Runoff resulting from snowmelt and rainfall in February of 197^ 3 one
month after the third application to winter applied plots also resulted
in minimal nutrient discharges. Losses in runoff and sediment did
not exceed 0.5 and 0.15 kg/ha respectively, and were lowest for the
winter applied plots. In general, residual losses of these two
elements from the past spring and summer applications, contributed
more to surface water and sediment discharges than a recent winter
application. The 35 t/ha rates, regardless of the time of application,
yielded essentially a zero discharge.
An intense rainstorm in June 197^ (^-6 cm in 75 minutes) occurred 12
days after the last summer application was applied on top of growing
corn. The previous winter and spring applications had already been
plowed down. Runoff and sediment losses were relatively low and
compared to losses incurred during an intense storm in August 1972.
Nitrogen in runoff and nitrogen and phosphorus in sediment did not
exhibit a significant change relative to the rate and timing of manure
application. Phosphorus showed a small but significant increase in
runoff water for the summer application, owing to the very recent
addition of manure.
The relationship between nutrient discharge and quantity of runoff
water for these selected drainage events were almost non-existent.
The data points contained considerable scatter because of varying
soil surface conditions, which influences runoff, and a large amount
of variability in nutrient concentrations, depending on the time of
the year runoff occurred in relation to the lapsed time since manure
disposal.
WINTER DISPOSAL
Accumulative nutrient losses from January to April for three con-
secutive (1972-197^) winter applications was studied. The main
emphasis was placed on the rate of winter application and the varia-
tion in nutrient losses that can be expected from year to year. A
comparison of several weather parameters was considered.
The winter of 1972 was fairly typical in terms of average precipitation
where the winters of 1973 and 1971+ were below normal. In addition,
during the winter of 1972 there was a considerably greater number of
days in which the soil was frozen (62 days) compared to 12 and 0 days
for 1973 and 197^, respectively. Soil temperatures at 10 cm under
sod was used as the criteria.
Nutrient losses of nitrogen and phosphorus as averaged over all rates
of application was considerably greater in 1972 in comparison to the
other years. Small differences existed between the winter of 1973
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and 197U. Actual runoff values as averaged for the three rates of
application for nitrogen was 16, 1 and 0.2 kg/ha for 1972, 1973 and
1974, respectively. Phosphorus values averaged 3.5, 0.7, and 0.01
kg/ha for the three respective years. Adverse weather conditions
during and after the winter disposal in 1972 was largely responsible
for increased discharges in runoff, especially at the 100 t/ha rate '
which was applied on top of dense melting snow, allowing for collec-
tion of data under extreme conditions .
The rate of application was extremely interesting over this three
year winter period. Ignoring the 100 t/ha rate for the winter of
1972, because it was applied under conditions far removed from the
35 and 200 t/ha rates, the 200 t/ha rate resulted in approximately
h times the nitrogen and phosphorus losses in runoff in comparison
to 35 t/ha during 1972, but were essentially identical in 1973 and
197^. Even more interesting, the 35 t/ha rate applied in the
winter across an array of weather patterns did not show any signifi-
cant differences between the three years . Resultant nitrogen and
phosphorus losses were less than 1.5 and 0.5 kg/ha respectively.
With the exception of spreading on melting snow, nutrient loadings
from the modest rate of 35 t/ha may well fall into the acceptable
range when standards are established.
It was postulated that surface water loadings were greatest during
1972 because of the timing of a snow melt event , a more nearly normal
amount of precipitation and a greater number of days when the soil
was frozen. Sediment losses of nitrogen and phosphorus, however,
were greatest during the winter of 1973. When dealing with sediment
losses the condition of the soil surface is all important. With a
given amount of precipitation, sediment yields would be greatest on
an exposed surface as compared to an unexposed surface. The number
of days of snow covered soil in 1972, 1973 and 1971* were 75, 39 and
6U, respectively. In theory, soil protection from rainfall impact
resulting from winter rains was lower in 1973, than in 1972 or 197^
because of less snow cover.
The greatest amount of sediment discharged in 1973, occurred from
a single runoff event lasting 3 days as a result of precipitation,
mostly in the form of rain. At the onset of runoff, the soil was
without a cover of snow. The resultant sediment yield contributed
greatly to the cumulative three months loss. Nutrient losses in
sediment were not significantly different between the winters of
1972 and
NUTRIENT CONCENTRATIONS
Average nutrient concentrations and frequency distributions for
nitrogen (NH^-N, lOg-N) and phosphorus (soluble inorganic and
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total soluble) in surface runoff and tile effluent vere determined.
Calculations of nitrogen and phosphorus concentrations and associated
variability had been made for two complete manure application cycles
(19T2, 1973).
The most variable nutrient element in runoff was ammoniacal nitrogen.
The greatest mean concentrations were associated with the winter 100
and 200 t/ha treatments (8.2 and k.5 ppm, respectively). Three
extremely high concentrations (100+ ppm) were responsible for the
larger average concentrations. The three outlying observations all
occurred from winter disposal as a result of a single snowmelt event
of February 1972. With the exception of these two treatments, mean
treatment concentrations were 1 ppm or less. Associated variability
ranged from 100-^75%.
Average nitrate-nitrogen concentrations in runoff displayed a
smaller degree of variation between drainage events as compared to
ammonium nitrogen. Mean concentrations ranged from 2.2 to 5-5 ppm
with little reflection on treatment.
Frequency distributions of nitrogen in surface water effluent
showed that approximately &0% of the frequency of ammonium nitrogen
concentrations were less than 1.0 ppm and 90% of the frequency of
nitrate nitrogen concentrations were less than 10 ppm.
Analytical determinations were made for both soluble inorganic and
total soluble phosphorus, the numerical difference being composed of
the soluble organic fraction. Like ammoniacal nitrogen, total soluble
phosphorus exhibited the greatest mean concentrations for the 100 and
200 t/ha application rates (2.6 and 3.1 ppm respectively). Extreme
concentrations, which markedly shifts the mean to higher levels, at
the two higher rates of application, occurred during the winter of
1972 and were mainly associated with a single snow melt event in
February. The average concentration of soluble phosphorus for the
35 t/ha winter treatment (0.9 ppm) was well in line with average
concentrations for the various disposal rates for the spring and
summer applications, which ranged from 0.3-1.1 ppm. Occurrences
of concentrations less than 1.0 ppm were on the order of 80-90$ of
the time.
The concentration of these same forms of nitrogen and phosphorus
had been determined in tile effluent on a weekly sampling basis.
Only the 35 and 200 t/ha rates at each disposal period was studied.
Mean concentrations of ammoniacal nitrogen were an order of magni-
tude lower in tile effluent in comparison to surface runoff. Mean
concentrations for the various treatments ranged from 0.06 to 0.25
ppm. Concentrations of less than 0.1 ppm occurred nearly 85% of the
212
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time with little differences between the timing and rate of manure
application.
Nitrate nitrogen, unlike ammoniacal nitrogen, moves readily with
water through the soil profile. Mean nitrate nitrogen concentra-
tions in the effluent ranged from 7 to 22 ppm and contained a high
degree of variation between sampling periods. The lowest mean concen-
tration was related to the plowing down of 35 t/ha in the spring. The
frequency of nitrate nitrogen concentrations exceeding 10 ppm ranged
from^45-70$ of the time. The 200 t/ha rates, and the average effect
of winter and summer disposal periods, approached the 10% level while
the 35 t/ha rates and the average effect of the spring application
accounted for the 45% frequency level.
learly 85% of the total soluble phosphorus in tile effluent is com-
posed of the soluble inorganic fraction. Mean total soluble phosphorus
concentration ranged from 0.01 - 0.1 ppm. Average concentrations for
the winter and spring disposal periods were approximately 10 times
greater at the higher rate of application, but little difference
between rate of application was evident for the summer disposal period.
Roughly 80% of the total soluble phosphorus concentrations as observed
over all drainage events were less than 0.1 ppm.
RAINFALL SIMULATION
An irrigation experiment was initiated to study the movement of
soluble nitrogen and phosphorus with time during a runoff event on a
single plot that received 200 t/ha as a summer application. Nutrient
concentrations in surface runoff did not vary greatly with the fluc-
tuations in discharge water and a nearly constant concentration was
maintained. Nutrient concentrations only began to drop at the
cessation of runoff. The last k hours of flow was 'tail flow'
in which laterally moving subsurface water, at a shallow depth,
is being intercepted by the drainage ditch and diverted to the record-
ing flume. Concentrations of nitrogen and phosphorus in the subsur-
face water were somewhat lower than in the water moving across the
surface.
The discharge rates of inorganic nitrogen and total soluble phosphor-
us in runoff were calculated. Since the quantity of nutrients dis-
charged is directly proportional to the flow and nutrient concentra-
tions were relatively constant, a linear response was achieved between
quantity of nutrients removed versus flow.
Similar calculations were made for tile effluent. Nitrate nitrogen
concentrations were inversely related to flow while phosphorus con-
213
-------
centrations were directly proportional to flow. Nitrate concentra-
tions were considerably higher in tile effluent but lower in soluble
phosphorus than surface water concentrations.
Nitrate discharge exhibited a poor linear relationship with flow.
Phosphorus discharge displayed a quadratic response, not unexpectedly,
since the highest concentrations were noted at peak flows.
SOIL RETENTION EFFICIENCY
The retaining efficiency of the soil for nitrogen and phosphorus
was calculated on the basis of nutrient inputs from manure and the
loss to the environment via runoff and sediment erosion. The in-
clusion of tile outflows were ignored because the 100 t/ha rate was
not tile drained, making relative comparisons difficult.
The soil system in itself appeared to be an excellent disposal medium
for dairy manure. The retaining efficiencies ranged from 89 to 99%
for the imposed treatments for both nutrients. The lowest efficiency
rating appeared for the winter applied 100 t/ha treatment. The reason
for the lower retention was due primarily to the disposal of this
treatment on dense melting snow in 1972.
SOIL ANALYSIS
Initial and terminal soil samples were obtained to determine the
relationship between successive manure inputs and the increase in
soil concentration of total nitrogen, available phosphorus and
organic matter.
Increased rates of application, increased the concentration of these
constituents in the soil as the result of three successive annual
applications. In many cases, the 35 t/ha rate of application actually
showed a negative response to manure additions. It was felt,
however, that after a longer period of successive manure inputs, equi-
librium will become established, and a positive increase will result.
A decay series for the mineralization of organic nitrogen from manure
was calculated to determine the availability of nitrogen for plant
growth and for potential nitrogen losses. A decay series of .55 -
.30 - .16 was calculated. For a three year period, 55% of the
organic nitrogen was mineralized from the first years input. The
second year, 55% of the current input was mineralized plus 30%
from the residual of the first year. After the third year, 55% was
mineralized from the third years input, plus 30% of the residual
from the second year, plus 16% of the residual from the first year.
The total organic nitrogen input minus the sum of the organic nitrogen
214
-------
mineralized approximated the increase in soil organic nitrogen after
three years.
CROP RESPONSE
Corn responded significantly to increasing rates of manure applica-
tion. However, the efficiency of utilization of nitrogen by the corn
crop dropped markedly as the rate of application increased. Once
adequate supplies of nitrogen are provided, additional increments
result in poor nitrogen conservation. Rates of manure application
in the neighborhood of 35 t/ha combined with an experimentally deter-
mined rate of mineral fertilizer could result in optimum nitrogen
conservation.
MANURE MANAGEMENT GUIDELINES
Due to extreme climatological variability within years as well as
between years, nutrient losses become highly variable in themselves.
Nevertheless, some very important principals have been observed and
preliminary guidelines have been formulated. The guidelines discuss
the watershed and dairy waste management aspects in relation to land
application of manure and water quality.
COMPUTER SIMULATION FOR CONTROL LEGISLATION
A study of animal waste disposal legislation and its impact on dairy
farms has been estimated with a mathematical computer simulation model.
The model used was developed for the particular purpose of examining
the effect of some hypothetical legislative controls designed to
reduce pollution related to dairy manure disposal. A number of
interesting observations can be seen from the results of the modeling
procedures which have been presented.
1. The hypothetical controls which were studied exert their greatest
influence over the dairy farms by way of reducing the acreage of
land which is available for manure disposal. When this is coupled
with low manure spreading rates, such as with Restriction Level 2,
the controls simply prevent a herd size which is representative of
today's dairy industry being reached without violating the restric-
tions.
2. At herd densities of less than 1.2k cows/ha (0.5 cows per acre),
it appears possible to meet the requirements of limited manure
disposal control, those of Restriction Level 1 without any sig-
nificant reduction in farm income. Combined controls on manure
spreading rates and fertilizer application rates have little
effect on farm income where herd size is small, less than 0.25
215
-------
cows/ha (0.1 cows/acre). These combined controls appear to
reduce total losses of nutrients to surface and ground water at
Restriction Level 2.
3. The greatest losses of nutrients to surface water appeared to
be associated with soil erosion. Any change in management of
the farm, brought about by restrictions on manure disposal,
which results in and increase in soil loss will increase losses
of nutrients to surface waters. This is especially true of
changes brought about by a regulation which causes more land
to be cultivated than before the regulation was enacted.
U. An increase in the area of cultivated land may result from legis-
lation which requires that manure be disposed of only by utiliza-
tion in a crop production program. This increase in cultivated
land is most likely to occur on farms with poor soils. This
means that the effect of a legislative control will be different
on farms with soils of different suitability production. If
legislative controls result in increases in cultivated land,
there may be an increase in losses of nutrients to surface
waters because of the soil loss factor discussed in (3) above.
These same controls may, however, be effective in reducing losses
of soluble nutrients in runoff and in water percolating to the
ground water.
5. Increasing cow/land ratios increased the loss of nutrients to
surface and groundwater from farms with poor soils in two ways;
(a) by increasing the proportion of land cultivated for feed
requirements; (b) by increasing the quantities of manure to be
disposed of.
On farms with productive soils, land which can be profitably
cultivated will be cropped regardless of the size of the dairy
herd, and most manure can be utilized in crop production. Thus
cow/land ratios have little effect on losses from these farms
unless large herd sizes are involved.
6. The effect of some controls on manure disposal is to prevent
certain areas of land being used for manure disposal. At
Restriction Level 2, this reduces the maximum cow/land ratio
which can be attained, on New York farms used in this study, to a
level of approximately .30-.32 cows/ha (0.12-0.13 cows/acre), far
below usually suggested values for adequate manure disposal. The
smaller the farm, the greater the proportion of the total area
which is unavailable for manure disposal under these controls. If
only those areas of the farm which can be used for manure spreading
are considered, then the cow/land ratio is closer to 0-99 cows/
216
-------
ha (O.U cows/acre). Only by considering that land which is
available for continuous corn production alone, could cow/land
ratio be significantly increased above 0=99 cows/ha (O.b cows/acre)
at the high level of control of Restriction Level 2.
It is possible to meet the requirements of the controls by changing
cropping practices. A shift from alfalfa to grass production for
hay or hay-crop silage enables more land to be used for manure
disposal. A reduction in corn acreages with a corresponding
increase in the area of small grains makes for a more even dis-
tribution through the year of land areas on which manure may be
spread. The availability of small grain stubble for manure
spreading in the late summer is a reason for this change in
cropping practices. The changes in cropping practice take place
in spite of the lower income which the substituted crops bring
to the farm.
217
-------
SECTION VIII
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225
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SECTION IX
GLOSSARY
Code of Practice - Guidelines suggested practical measures to be
taken under a given set of circumstances. Usually compliance with
the code of practice implies that an effort has "been made to control
a certain problem, and avoids punitive damages in subsequent lawsuits,
Constraint - In linear programming, a constraint is usually consid-
ered to be a set of conditions which must be equal to each other,
or greater or less than some "right hand side" value. In this
study, the term has also been used to describe hypothetical legis-
lative controls which reduce the freedom of decision making enjoyed
by a farmer with respect to his farm management decisions.
Conversion Table - FOR ENGLISH AND METRIC UNITS.
To convert col 1 Column 1 Column 2
to col 2 multiply
by:
To convert
col 2 to col
1 multiply by
Length
0.621 Kilometer, km Mile, mi 1.609
1.09^ Meter, m Yard, yd 0.91^
0.39^ Centimeter, cm Inch, in. 2.5^0
Area
0.386 Kilometer2, km Mile2, mi2 2.590
2.1*71 Hectare, ha Acre, acre O.U05
226
-------
Conversion Table - (Cont'd.)
To convert col 1
to col 2 multiply
by:
Column 1
Column 2
To convert
col 2 to col
1 multiply by:
Mass
1.102
2.205
O.UU6
0.891
(9/5 °C) + 32
Ton (metric)
Kilogram, kg
Ton (English)
Pound, lb
0.9072
Yield
Ton (metric)/ Ton (English)/ 2.2kO
hectare acre
kg/ha Lb/Acre 1.12
Temperature
Celsius, C Fahrenheit, F 5/9(°F-32)
Denitrification - Microbial conversion of nitrate nitrogen to
nitrogen or nitrogen oxide gasses. Carried out by soil organisms
in an anaerobic environment.
Enrichment Ratio - The increase in the level of content of a substance
in soil or water, brought about by a land use activity, over that which
would occur if no activity, other than natural evolution, was to be
imposed on the land.
Externality - External (dis) economy; an economic influence on the
activities of another, with no connection or "feed back" to the
economics of the activity causing the externality. Pollution is an
external diseconomy when someone not connected to the pollution
causing activity must suffer personal or economic loss as a result of
the pollution, or must pay the cost of eliminating it with no
recourse to those causing it.
Legislation - Legislative controls: a written statement enacted
into law, the violation of which is an offense punishable under the
law.
227
-------
Manure - Animal excreta with or without added water or solid
material, in a form suitable for spreading on the land.
a- Dumping - The practice of disposing of manure by applying very
high application rates to an area of land on which no crop is
grown.
b- Spreading - The practice of applying manure to a crop, or to
land in preparation for a crop, with the intention of benefitting
the crop as well as disposing of the manure.
c. Stockpiling - Holding or storing manure in above ground piles
for spreading or dumping at a later date.
d. Treatment - Any practice which alters the chemical or physical
nature of the manure, or both. Usually carried out in conjunction
with a manure disposal program.
Mineralization - The microbial break-down of organic material from
any source, with a consequent liberation of inorganic forms of the
nutrients contained in the original organic material.
Net Revenue - The difference between the costs and the returns from
the operation of the farm, excluding the value of labor supplied by
the farmer and his immediate family and the costs of interest and
taxes which must be paid on the land resources of the farm.
Optimization - Process of selecting the mix of activities, and the
levels of these activities, which is optimum under the desired con-
ditions - in this study that mix which gives the maximum net revenue
to the farm operation.
Percolation - Seepage; the quantity of water which moves out of
the soil, downwards or horizontally, and is not accounted for in
runoff and evapotranspiration. Percolation or seepage nitrogen
is that quantity of nitrogen which leaves the soil by this route.
Pollution - The addition of nutrients or other contaminants to the
environment which results from the activities of man.
Sediment - The solid material which is carried from its place of
origin by runoff water. Sediment nutrients are those nutrients
contained in this sediment.
Selective Erosion Index - A measure of the physical and chemical
processes which result in the sediment from erosion of a soil
being higher in content of a nutrient, or other material, than
the soil itself.
228
-------
Shadow Prices - The marginal value product of a resource - the
amount of change in the net revenue which would occur if a limited
resource or constraint value was changed by one unit.
Volatilization - The loss of an element by transfer from the
soluble state to the vapor state — specifically the loss of
ammonia nitrogen by this mechanism brought out by drying, high pH
or freezing.
229
-------
SECTION X
APPENDIX
Table Al. ANNUAL DISCHARGE OF WATER, INORGANIC NITROGEN AND
SOLUBLE PHOSPHORUS IN SURFACE RUNOFF FOR INDIVIDUAL
PLOTS, 1972.
Soil
mg't
Poor
Good
Time
of
applic
Winter
Spring
Summer
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
Runoff,
cm
lU.i
35.5
13.U
lU.6
28.3
19.2
7,9
62.3
50.2
6.5
9-6
6.0
6.6
17.0
11. U
20.7
23. ^
2.6
Inorganic -N,
kg/ha
6. In
90.73
1^.13
5.01
5.18
5.79
3.10
25.60
19.96
U.25
35.61
6.39
2.67
17-07
18.50
17.17
7.08
1.77
Total solu-P,
kg/ha
0.988
15-021
5.208
0.317
0-736
1.506
0.263
3.56^
1+.239
0.335
5.319
2.3^1
0.121
0.276
7.18H
2.12U
0.902
0.256
Plot
no.
^,15
18
6
5,22
13
1
8,16
17
3
21,2k
19
11
2,9
10
7
12,20
lU
23
230
-------
Table A2. AMUAL DISCHARGE OF WATER, INORGANIC NITROGEN AND
SOLUBLE PHOSPHORUS IN SURFACE RUNOFF FOR INDIVIDUAL
PLOTS, 1973.
Soil
mg't
Poor
Good
Time
of
applic
Winter
Spring
Summer
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
Runoff,
cm
5-56
11.86
2,99
5.31
11.23
7.^7
1.85
17.98
Yl.lk
2.51
2.21
2.21
2.kk
H.95
1=96
5.08
6.02
0.30
Inorganic -N,
kg/ha
0.59
k. 11
0.5^
0.76
3.79
1.9U
o.in
k .jk
U.56
1.62
1.67
0.86
O.U9
1.29
0.51*
1.63
1.62
0.11
Total solu-P,
kg/ha
0.37
3.1U
1.93
0.08
0.15
0.2k
0.12
0.59
0.60
OA5
O.U2
0.91
0.02
0.05
1.36
0.17
0.10
0.02
Plot
no.
*,15
18
6
5,22
13
1
8,16
17
3
21, 2l*
19
11
2,9
10
7
12,20
Ik
23
231
-------
Table A3. ANNUAL DISCHARGE OF INORGANIC NITROGEN AND TOTAL SOLUBLE
PHOSPHORUS IN SURFACE RUNOFF FOR GIVEN TREATMENTS. 1972,
1973.
Treatment N, kg/ha P, kg/ha
1972 1973 Ave. 1972 1973 Ave.
Runoff, cm
1972 1973 Ave,
Time
Winter
Spring
Summer
Rate, mt/ha
35
100
200
Soil mg't
Good
Poor
Overall Means
21.la 1.5a 11.3a
7.7b 1.2a k.ka
11.9c 1.9a 6.9a
5.1|a 0.9a 3.6a
30.2b 2.9b 16.5b
11.Ic 1.5a 6.3ab
11.2a l.la 6.2a
15.8b 1.9a 8.8a
13.6a 1.6b 7.6
3.8a l.Oa 2.W
1.3b 0.2b 0.8a
1.7b 0.2b l.Oa
0.7a 0.2a O.lta
i*.3b 0.8b 2.6a
3-5c 0.9b 2.2a
1.8a 0.3a
2.8b 0.7b
l.Oa
1.8a
2.2a 0.5b l.U
13.2a k.3a 8.9
li|.7a 5.la 9-9
2^.4b 6.6a 15.5
11.7a 3.8a 7-8
29.5b 9-lb 19-3
17-3c 5.la 11.2
11. Ua 3.0a 7.2
23.6b 7-6b 15.6
17-5a 5-3b 11.U
a
Means followed by the same letters are not significantly different @
5% level in the verticle column and for row values in the overall means.
232
-------
Table AU. ANNUAL DISCHARGE OF SOIL, TOTAL NITROGEN, TOTAL
PHOSPHORUS AND ORGANIC MATTER IN SEDIMENT FOR
INDIVIDUAL PLOTS, 1972.
Time
Soil of Rate,
mg't applic t/ha
Poor Winter 35
100
200
Spring 35
100
200
Summer 35
100
200
Good Winter 35
100
200
Spring 35
100
200
Summer 35
100
200
Soil
loss, Total-N,
t/ha kg/ha
1.767
U.6U9
3.361
0.901
1.867
15.751
.1*85
5.870
it. 023
0.373
2.051+
0.318
0.539
OA52
2.211
0.369
0.368
0.020
6.2
26.6
17-3
3.7
8.7
U8.0
1-7
25-3
15.7
1.2
9.8
1.6
2.2
1.8
13.8
1.5
1.5
0.2
Total -P,
kg/ha
2.59
9-97
6.27
1.1+2
3.22
20.26
0.68
11.21
6.82
0.1+5
3.17
0.66
0.66
0.61
H.3^
0.60
0.59
O.Oil
Organic
matter,
kg/ha
107
6ll|
316
65
155
970
28
32li
313
25
277
30
111
35
2hk
29
27
2
Plot
no.
M5
18
6
5,22
13
1
8,16
17
3
21,21+
19
11
2,9
10
7
12,20
Ik
23
233
-------
Table A5. ANNUAL DISCHARGE OF SOIL, TOTAL NITROGEN, TOTAL PHOSPHORUS
AND ORGANIC MATTER IN SEDIMENT FOR INDIVIDUAL PLOTS, 1973.
Soil
mg't
Poor
Good
Time
of
applic
Winter
Spring
Summer
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
Soil
loss ,
t/ha
l.kk
2.60
0.31
1.k2
2.83
U.76
0.96
1.31
0.88
0.19
0.28
0.53
0.35
0.66
0.79
0.81
1-99
0.01
Total-N,
kg/ha
6.2
17-0
2.6
7-1
11.6
15-5
3.9
6.2
3.k
0.8
1.8
3.9
1.5
2.6
3.5
3.8
10.6
0.1
Total-P,
kg/ha
2.7
6.9
1.1
3.2
k.9
6.7
1.7
3.1
1.5
O.k
0.8
1.8
0.6
l.l
1.7
1.6
U.5
0.03
Organic
matter,
kg/ha
130.5
305.6
55-8
128.8
253.1
357-6
72.0
95-0
75-7
16.1
32.8
83.5
31.7
5^.1
60.0
9^.0
19^.8
1.1
Plot
No.
^,15
18
6
5,22
13
1
8,16
17
3
21,2k
19
11
2,9
10
7
12,20
Ik
23
234
-------
Table A6. ANNUAL DISCHARGE OF SOIL, TOTAL NITROGEN, TOTAL PHOSPHORUS AND ORGANIC MATTER IN SEDIMENT
FOR GIVEN TREATMENTS. 1972, 1973
Treatment
Total-N, kg/ha
1972 1973 Ave.
Total-P, kg/ha
1972 1973 Ave,
Org. mat., kg/ha
1972 1973 Ave.
Soil loss, kg/ha
1972 1973 Ave.
Time
Winter
Spring
Summer
Rate,
mt/na
35
100
200
Soil mg't
Good
Poor
Overall
Mean
8.7 ab
10.6 b
6.1 a
2.7 a
12.3 b
16.2 c
3.2 a
13.8 b
8.5 a
IK 9 a 6.8
6.3 a 8.1*
lt.lt a 5.2
3-9 a 3.3
8.3 b 10.3
IK 8 a 10.5
2.9 a 3.0
7-5 b 10.6
5.2 b 6.8
3.2 ab
U.I b
2.6 a
1.1 a
it. 8 b
6. it c
1.1 a
5.6 b
3.3 a
2.1 a
2.8 a
2.0 a
1.7 a
3.5 b
2.2 a
1.3 a
3.3 b
2.3 a
2.6
3. U
2.3
l.U
it. 2
U. 3
1.2
U. ^
2.8
188 a
202 a
97 b
U9 a
237 b
312 c
67 a
256 b
162 a
96 a
131 a
109 a
78 a
156 b
105 a
59 a
150 b
105 b
192
166
103
6it
196
208
63
203
13U
1832 a
289lt a
Iit97 a
739 a
151*2 b
it280 c
665 a
3it85 b
2075 a
875 a
1582 b
965 a
862 a
162U b
1215 ab
579 a
1702 b
nia b
1351*
2238
1231
800
2083
27^8
622
2593
1608
to
CO
Cn
Means followed by the same letter are not significantly different
column and for the row values in the overall means.
level in the verticle
-------
Table A?. DAIRY MANURE COMPOSITION, 1972.
to
co
Time
Winter
mean
std dev
range
Spring
mean
std dev
range
Summer
mean
std dev
range
Combined
mean
std dev
range
Dry matter,
%
23.25
6.10
13.0-39.8
10. Ik
3. ia
15-0-33.0
19. W
2.38
16.0-27.0
20.99
k.5k
13.0-39-8
NHrN,
%
0.51
0.37
0.12-1.61
0.7!+
0.27
O.lU-1.28
0.81*
0.18
0.1*3-1.20
0.67
0.30
0.12-1.61
Total -N,
at
/«
1.90
0.7l*
0.99-3.66
2.80
0.6U
1.11-1*. 02
2.80
0.50
1.83-1*. 63
2.1tl
0.65
0.99-^.63
Inorganic -P,
at
7°
0.16
0.11
0.0l*-0.1*5
0.19
0.10
0.02-0.39
O.ll*
0.11
0.01-0.38
0.16
0.11
0.01-0.1*5
Total solu-P,
of
/"
0.21
0.11
0.07-0.1*7
0.31*
0.15
o.oi*-o.6i*
0.31
0.10
0.01-0.52
0.28
0.12
0.01-0.61*
Total -P,
of
ft
0.1*7
0.19
0.16-1.03
0.51
0.10
0.28-0.70
0.55
0.10
0.38-0.81
0.51
O.lU
0.16-1.03
-------
Table A8. DAIRY MANURE COMPOSITION, 1973.
to
co
-a
Time
Winter
Mean
Std Dev
Range
Spring
Mean
Std Dev
Dry matter,
at
ft
23.62
1.29
lU.O - 38.0
19.17
2.37
Nlty-N,
%
0.3kO
0.173
O.li - 0.66
0.168
0.029
Total -N,
%
2.175
0.809
0.68 - 3.80
2.569
0.389
Inorganic-P,
%
0.192
0.116
O.Ol* - 0.1*5
0.380
0.069
Total solu-P,
%
0.301
0.168
0.05 - 0.58
0.1*01
0.080
Total -P,
%
0.511*
0.162
0.28 - 0.87
0.61*5
0.079
Range l6.0 - 27.0 0.11 - 0.22 1.90 - 3-32 0.23 - 0.1*9 0.2k - 0.50 0.1*6 - 0.80
Summer
Mean 2l*.65 O.lUo 2.296 0.310 0.333 0.679
Std Dev 5.3k 0.01*1* 0.67!* 0.135 O.lUo 0.170
Range 17.3 - 38.0 0.07 - 0.23 1.30 - 3-70 0.12 - 0.55 O.ll* - 0.58 0.1*9 - 1.10
Combined
Mean 22.1*8 0.216 2.3^1 0.29^ 0.3^*5 0.6lU
Std Dev 5-59 0.136 0.679 0.131* 0.139 0.159
Range lU.O - 38.0 0.07 - 0.66 0.68 - 3.80 0.0k - 0.55 0.05 - 0.58 0.28 - 1.10
-------
Table A9- TOTAL NUTRIENT INPUTS FEOM DAIRY MANURE, 1972
Soil
mg't
Poor
Good
Time
of
applic
Winter
Spring
Summer
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
Dry
matter,
kg/ha
8548
24621
47418
6448
18052
43260
5657
19008
43347
9448
19281
51056
5948
17253
40894
5980
19148
46345
NH^-N,
kg/ha
20
139
24l
58
144
280
57
179
353
26
136
188
52
l43
174
52
128
315
Total-N,
kg/ha
153
455
767
202
533
1012
169
563
1106
128
447
778
184
578
868
194
525
1034
Total-P,
kg/ha
40
129
129
34
95
208
37
112
236
38
88
224
34
96
164
36
110
197
Plot
no.
>M5
18
6
5,22
13
1
8,16
17
3
21,24
19
11
2,9
10
7
12,20
14
23
238
-------
Table A10. TOTAL NUTRIENT INPUTS FROM DAIRY MANURE, 1973.
Soil
mg't
Poor
Good
Time
of
applic
Winter
Spring
Stumer
Winter
Spring
Summer
Rate,
t/ha
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
35
100
200
Dry
matter ,
kg/ha
1096T
28286
V213V
7037
18957
UOU8U
6980
23275
57562
5682
30558
1*6927
5186
19^70
38203
5902
30930
50178
NH^-N,
kg/ha
26
55
129
11
31
60
11
29
68
31
58
JM
11
39
62
11
18
65
Total -I,
kg/ha
158
>*6o
898
169
V39
995
181
550
1127
176
370
819
16V
572
828
167
511
1082
Total-
kg/ha
50
129
215
V7
12V
259
57
157
3kO
1+2
95
208
U2
121
235
52
1U8
316
-P, Plot
no.
^,15
18
6
5,22
13
1
8,16
17
3
21,2^
19
11
2,9
10
7
12,20
ih
23
239
-------
Table All. AVERAGE SURFACE RUNOFF (R) AND SOIL LOSS (SL) FOR SELECTED RUNOFF EVENTS.
Date
Treatment
35 mt/ha
Winter
Spring
Summer
100 mt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Summer
2/29/72
R
cm
.88
1.11
3.32
If. 06
1.66
3.75
1.32
3.90
3.76
SL
kg/ha
5-9
33.8
50.1
276.7
11.2
26.6
25.9
670.1
U.5
6/26/72
R
cm
3.71
3.^3
5.814
5.61*
7.72
11.61
3.30
It. 72
7.26
SL
kg/ha
583.1
321.5
96.7
1178.7
379-5
5^6. It
1321*. 0
6997. ^
5^7-9
8/27/72
R
cm
.81
.60
.79
1.07
• 70
.77
.1*6
.89
.81
SL
kg/ha
188.3
197-7
lltO.2
352.7
139-8
203.5
81*. 22
233.3
109.0
12/7/72
R
cm
.61
.32
.53
1.1*0
1.26
2.2k
.83
.51
1.66
SL
kg /ha
l6.lt
15-7
U.5
a
1*0.0
29.0
3.0
85.0
6.6
3/19/73
R
cm
2.37
1.58
2.06
3.12
3-30
2.90
1.13
2.53
1.52
SL
kg /ha
763.3
677.2
81*2.5
io6U.o
1093.6
830.0
327.3
2it55.9
272.8
V6/73
R
cm
1.20
1.55
1.25
1.98
2.82
i*.oo
1.19
1.32
lt.17
SL
kg/ha
1*1.8
150.8
1*1.9
122.0
358.5
580.6
82.9
212,5
113.8
to
^
o
a
Unavailable due to small sample size.
-------
Table All (Continued). AVERAGE SURFACE RUNOFF (R) AND SOIL LOSS (SL) FOR
SELECTED RUNOFF EVENTS.
to
Date
Treatment
35 mt/ha
Winter
Spring
Summer
100 mt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Summer
12/27/73
cm
.10
.10
—
M
.33
1.36
.03
.09
.36
SL
kg/ha
.78
.78
~~
U.7
5-5
8.5
.2
3.1
12.2
2/2V7^
R
PIT)
.01
.06
.07
-
.30
.51
.09
.10
.37
SL
kg /ha
.20
I.h2
"*"
-
13.6
25.1
6.6
30.6
9-30
6/llM
R
cm
.27
.25
.22
.09
.38
.19
.15
.28
.09
.SL
ke/ha
11*6.2
58.2
70.9
2^.2
90.8
5.6
72.7
322.8
k.2
-------
Table A12. AVERAGE CONCENTRATIONS OF INORGANIC NITROGEN IN SURFACE RUNOFF FOR SELECTED RUNOFF
EVENTS. VALUES EXPRESSED IN ppm.
Date
Treatment
35 mt/ha
Winter
Spring
Slimmer
100 mt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Sximmer
2/29/72
NH^-N
11.0
.36
6.99
113.0
M
.5^
83.75
ll.UU
.27
N03-N
.05
.814
.2k
.73
1.16
.95
.95
.U3
.82
6/26/72
NH^-N
.09
.10
.13
.11
.10
.35
.11
.23
.90
NO -N
8.3l4
8.29
7.51
10.5
8.95
3.38
3.7
U.52
8.35
8/27/72
NH^-N
.06
.06
.07
.08
.06
.10
.05
.05
.12
NO -N
.88
.69
• 73
• 78
• 78
.80
.78
.69
1.9ii
12/7/73
NH^-N
.07
.07
.06
.05
.07
.08
.02
.08
.OU
NO -N
• 79
1.53
2.01
1.98
2.08
3.22
l.W
2.30
2.78
3/19/73
NH^-N
.39
.12
.20
1.31
.08
.09
1.06
1.15
.13
NO -N
5.^9
.73
2.36
3.59
1.145
.79
1.23
.80
2.62
V6/73
NH> -N
.17
.07
.06
.149
.07
.07
.31
.12
.06
NO -N
1.70
2.05
2.5^
2.53
2.32
2.26
2.68
2.96
2.19
to
M^
to
-------
to
£>•
CO
Table A12 (Continued). AVERAGE CONCENTRATIONS OF INORGANIC NITROGEN IN SURFACE RUNOFF
FOR SELECTED RUNOFF EVENTS. VALUES EXPRESSED IN ppm.
Date
Treatment
35 mt/ha
Winter
Spring
Summer
lOOmt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Summer
12/27/73
IHj^-N
.08
.06
_a
.12
.11
.11
.15
.08
.17
N03-N
3.33
2.73
-
6.5
25.62
10.00
19.15
.38
30.00
2/2V71*
NH^-N
.13
.61
1.02
-
.17
.2U
.29
.15
.31
N03-N
k.k9
2.26
3.30
-
9-56
6.^3
5-15
26.50
8.75
6/llM
NH^-N
.20
.25
1.90
.13
.5U
^. 99
1.03
.28
9-7^
NO_-N
2.26
U.80
.52
3.50
5.50
.03
3.75
3.63
11.25
No flow recorded.
-------
Table A13. AVERAGE INORGANIC PHOSPHORUS (SIP) AND TOTAL SOLUBLE PHOSPHORUS (TSP) IN SURFACE
RUNOFF FOR SELECTED RUNOFF EVENT. VALUES EXPRESSED IN ppm.
Date
Treatment
35 mt/ha
Winter
Spring
Summer
100 mt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Summer
2/29/72
SIP
2.98
.10
1.19
21.65
.06
.11
33.82
3.55
.05
TSP
It. 08
.11
1.62
22.55
.06
.12
3^.80
H.lt5
.06
6/26/72
SIP
.11
.10
.29
.18
.18
.87
.23
.W
1.U6
TSP
.20
.lit
.U8
.21
.28
1.03
.35
.62
1.71
8/27/72
SIP
.23
.09
.19
.27
.oU
.29
.17
.12
1.05
TSP
.32
.12
.21
• 3U
.09
.It5
.19
.lU
1.15
12/7/72
SIP
.16
.22
.21
.12
.18
.U6
.21
.59
.67
TSP
.3U
.31
.29
.17
.31
.59
.29
.72
.79
3/19/73
SIP
1.12
.09
.50
2.00
.09
.13
3.89
3.02
.ito
TSP
i.iu
.lit
.67
2.55
.13
.18
7.20
It. 07
• 55
it/6/73
SIP
.7U
.07
.13
1.90
.07
.17
3.35
.39
.32
TSP
.85
.09
.17
2. Oh
.09
.20
3.U2
.Itl
.3H
to
-------
to
tf*.
Ol
Table A13 (Continued). AVERAGE INORGANIC PHOSPHORUS (SIP) AND TOTAL SOLUBLE PHOSPHORUS (TSP)
IN SURFACE RUNOFF FOR SELECTED RUNOFF EVENTS. VALUES EXPRESSED IN ppm.
Date
Treatment
35 rat /ha
Winter
Spring
Slammer
100 rat /ha
Winter
Spring
Summer
200 rat /ha
Winter
Spring
Siommer
12/27/73
SIP
.06
.oU
_a
.12
.11
.57
.20
.52
1.3U
TSP
.10
.07
-
.It
.15
.58
.28
.57
1.U6
2/2U/7^
SIP
.614
.06
.26
—
.07
.38
.38
.21
.31
TSP
.71
.08
.29
-
.08
.39
.1*6
.27
.39
6/llM
SIP
.19
.13
1.27
.37
.16
1.66
.53
.29
5.20
TSP
.23
.15
1.52
.37
.17
2.68
.58
.32
8.3!*
No flow recorded.
-------
Table All*. AVERAGE TOTAL NITROGEN (TOT-N) AND TOTAL PHOSPHORUS (TOT-P) IN SEDIMENT FOR SELECTED
RUNOFF EVENTS. VALUES EXPRESSED IN PERCENT.
Date
Treatment
35 mt/ha
Winter
Spring
Summer
100 mt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Summer
2/29/72
Tot-N
.81*
.ho
• 59
.72
_a
.38
.Qh
.56
.85
Tot-P
.1*3
.11*
.25
.26
-
.15
.33
.18
.19
6/26/72
Tot-N
.36
.1*2
.68
.1*2
.1*6
.hh
.h9
.38
.52
Tot-P
.11*
.16
.17
.15
.11+
.19
.18
.16
.19
8/27/72
Tot-N
.36
.ho
.36
.39
.1+2
.38
.U6
.36
.52
Tot-P
.11+
.11+
.15
.17
.13
.16
.16
.11+
.19
12/7/72
Tot-N
.31*
A3
.39
.U7
.39
.50
.1*0
.1*5
.1*6
Tot-N
.21
.20
.20
.22
.18
.31
.27
.25
.22
3/19/73
Tot-N
Alt
.1*1+
.U5
.67
.38
.1*9
.90
.39
A5
Tot-P
.19
.20
.19
.27
.16
.22
.39
.18
.21
lt/6/73
Tot-N
.1*8
.1*1*
.143
.58
.1*2
.35
.68
.35
.1*2
Tot-P
.23
.17
.16
.26
.17
.23
.1*2
.16
.20
to
^
OJ
a
Unavailable due to small sample size,
-------
to
^
-d
Table Alk (Continued). AVERAGE TOTAL IITROGEN (TOT-N) AID TOTAL PHOSPHORUS (TOT-P) IK SEDIMENT
FOR SELECTED RUNOFF EVENTS. VALUES EXPRESSED IN PERCENT.
Date
Treatment
35 mt/ha
Winter
Spring
Summer
100 mt/ha
Winter
Spring
Summer
200 mt/ha
Winter
Spring
Slimmer
12/27/73
Tot-N
.56
.68
-
-
.61
.6k
.Ik
.kk
.60
Tot-P
.18
.20
-
-
.16
.27
.27
.12
.21
2/2k/lk
Tot-N
• 56
.68
-
—
.61
.6k
-
.kk
.60
Tot-P
.18
.20
-
-
.16
• 27
-
.12
.21
6/nM
Tot -I
.35
.314
.30
.1»5
.ko
.80
.kk
.ho
.90
Tot-P
.17
.16
.16
.22
.16
A9
.22
.16
.9^
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT
^6^0/2-76-187
2.
4 TITLE AND SUBTITLE
Design Parameters for the Land Application of Dairy-
Manure
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
Oct.n?
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
S. D. Klausner, P. J. Zwerman and D. R. Coote
!. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Agronomy
Cornell University
Ithaca, New York 1^853
10. PROGRAM ELEMENT NO.
1BB039
11. CONTRACT/GRANT MO.
s 800767
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Research Laboratory - Athens, GA
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Heorgia
13. TYPE OF REPORT AND PERIOD COVERED
Final __
14. SPONSORING AGENCY CODE
EPA/600/01
15. SUPPLEMENTARY NOTES
Prepared in cooperation with the Cornell University Agricultural Experiment Station.
16. ABSTRACT
The effects of climate, application rate of dairy manure, timing of application and
soil management practice were studied in relation to discharge of nitrogen and
phosphorus via surface runoff, sediment and tile effluent.
Losses of nutrients from the land were influenced by the rate and timing of manure
application in addition to the type of climatological event causing runoff. The
greatest discharge of nutrients resulted from applying manure on actively melting snow
Modest rates of application made in the winter during non-snowmelt periods resulted in
minimal losses. Concentrations of nitrogen in surface runoff as measured over time,
were lower than those found in tile effluent. The reverse was true for soluble phos-
phorus. The yield response of corn increased while efficiencies of nitrogen utiliza-
tion decreased at the higher rates of application.
A computer model dealing with the economic impact of control legislation was developed
Modeling approaches to farm scale environmental problems are feasible if assumptions
and simplifications do not influence the results too greatly, or in ways which are
unpredictable.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
:. COSATI Field/Group
land
economic analysis
surface drainage
subsurface drainage
computer simulation
yield
animal waste management
manure fertilization
guidelines
02/C/E
B. DISTRIBUTION STATEMENT
Release unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGtb
264
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
248
• U. S. GOVERNMENT PRINTING OFFICE: 1977-757-056/5468 Region No. 5-1
------- |