United States
Environmental Protection
Agency
Great Lakes
National Program Office
230 South Dearborn Street
Chicago, Illinois 60604
EPA-905/9-91-006C
GL-06C-91
v>EPA
Agricultural NFS Control of
Phosphorus in the New York
State, Lake Ontario Basin
Volume III The Influence of Tillage on
Phosphorus Losses from Manured Cropland
Printed on Recycled Pap<
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FOREWORD
The U.S. Environmental Protection Agency (USEPA) was created because of increasing
public and governmental concern about the dangers of pollution to the health and welfare
of the American people. Noxious air, foul water, and spoiled land are tragic testimony
to the deterioration of our natural environment.
The Great Lakes National Program Office (GLNPO) of the U.S. EPA was established in
Chicago, Illinois to provide specific focus on the water quality concerns of the Great
Lakes. The Section 108(a) Demonstration Grant Program of the Clean Water Act (PL 92-
500) is specific to the Great Lakes drainage basin and thus is administered by the Great
Lakes National Program Office.
Several demonstration projects within the Great Lakes drainage basin have been funded
as a result of Section 108(a). This report describes one such project supported by this
office to carry out our responsibility to improve water quality in the Great Lakes.
We hope the information and data contained herein will help planners and managers of
pollution control agencies to make better decisions in carrying forward their pollution
control responsibilities.
Director
Great Lakes National Program Office
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EPA-905/9-91-006C
February 1991
AGRICULTURAL NONPOINT SOURCE CONTROL OF PHOSPHORUS IN THE
NEW YORK LAKE ONTARIO BASIN
VOLUME 3. THE INFLUENCE OF TILLAGE ON PHOSPHORUS LOSSES
FROM MANURED CROPLAND
by
Paul D. Robillard
Michael F. Walter
Department of Agricultural Engineering
Cornell University
Ithaca, New York 14853
R005725-01/02
Project Officer
Mr. Ralph Christensen
U.S. Environmental Protection Agency
Great Lakes National Program Office
230 South Dearborn Street
Chicago, Illinois 60604
November 1987
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DISCLAIMER
This report has been reviewed by the Great Lakes National
Program Office, U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies
of the U.S. Environmental Protection Agency nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
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ABSTRACT
A sprinkling infiltrometer was used to evaluate total phosphorus (TP) and total
soluble phosphorus (TSP) losses in surface runoff from plots receiving manure application
rates of 22-135 MT/ha and from plots where manure had been incorporated to depths
varying from 0-20 cm. Both laboratory and field trials were conducted utilizing simulated
precipitation. Infiltrometer runs were repeated for various drying conditions of the soil
manure mixture at time intervals varying from 1-30 days.
Significantly higher TP and TSP loads in surface runoff were associated with
surface applications of manure immediately followed by a precipitation event. For the
standard 12-cm, 60-minute event, TP and TSP loads were as high as 13.4 and 7.7 kg/ha,
respectively. These loads were 20-25 times greater than observed TP, TSP loads from
control plots. Typically, the high loading rates were short-lived with the positive effects of
manure amendments on infiltration, moisture retention and phosphorus sorption being
observed after drying periods of 5-25 days. Generally, after several wet-dry cycles TP,
TSP loads approached control levels.
With the incorporation of manure to depths of 3,10 or 20 cm, both TP and TSP
loads were greatly reduced. In particular, minimal incorporation of 3 cm resulted in 70-
90% reductions in TP, TSP loads in surface runoff from the initial high loading case.
When TP, TSP loads were normalized for application rate, losses of TP, TSP in
surface runoff per kg of manure applied were greater for the lower rates. For the case of
TP, TSP loads normalized by depth of incorporation, losses from surface applications were
three to five times greater than that of other incorporation depths. Incorporation depths as
little as 3 cm indicated 50-60% reductions in TP, TSP, loads in surface runoff for each unit
of manure applied.-
The conflicting objectives of maintaining surface residues with reduced tillage
systems and minimizing phosphorus losses through manure incorporation reflect a need for
the development of tillage-manure systems. These systems could take advantage of three to
five year tillage rotations where a moldboard or chisel plow would be used periodically on
no-till fields. In addition, variable application rates and surface incorporation methods
could be utilized to decrease overall farm losses.
The sprinkling infiltrometer provides the basis for a promising method of on-site
evaluation of tillage-manure systems. The versatility of such an instrument in a laboratory
and field setting is advantageous. Tillage-manure systems and other phosphorus control
measures can be accurately compared using such techniques. Lastly, the accumulation of a
data bank from infiltrometer runs provides a basis for more comprehensive comparisons of
tillage-manure phosphorus control options.
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ACKNOWLEDGEMENTS
The support of several individuals is gratefully acknowledged. As Project
Officers, Mr. Ralph Christensen (United States Environmental Protection Agency,
Region V) and Ms. Patricia Longabucco (New York Department of Environmental
Conservation), generously assisted in all phases of the project. Mr. Tom DeRue
(District Manager) and Mr. J. C. Smith (District Technician) of the Wayne County Soil
and Water Conservation District, as well as Mr. Frank Winkler (District Conservationist,
Soil Conservation Service) were very helpful during all field data collection and farm
plot trials. Similarly, in Oswego County, Mr. John DeHoIlander (Field Manager) and
Mr. John Flanagan (District'Technician) of the Oswego County Soil and Water
Conservation District along with Mr. Michael Townsend (District Conservationist, Soil
Conservation Service) assisted us in all farm trials as well as providing other data
concerning conservation tillage practices and typical manure handling systems in the
county. Mr. Jim Tompkins, farm cooperator in Oswego County, and Gerry Fones,
District Board Chairman, provided valuable assistance during field runs. Roger and
Larry Arliss, Wayne County farm cooperators, generously supported us in all field
operations on their farm.
Ms. Tori Wishart of the Agricultural Engineering Department at Cornell
University provided invaluable assistance in all aspects of preparation of the final
report for this project.
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TABLE OF CONTENTS
Page
SECTION I INTRODUCTION 1
BACKGROUND 1
OBJECTIVES 1
REVIEW OF RELATED RESEARCH FINDINGS 2
NUTRIENT LOSSES FROM AGRICULTURAL AREAS 2
SEASONAL DIFFERENCES IN TP LOAD FROM CROPLAND 3
SOME EFFECTS OF MANURE ON THE HYDROLOGIC AND
NUTRIENT PROPERTIES OF SOIL 4
The Influence of Manure on Infiltration and
Moisture Retention 4
Organic Matter Accumulation and Decomposition 5
The Influence of Soil Moisture 5
Soil Management and Nutrient Availability,
Retention and Losses 6
THE EFFECT OF TILLAGE ON SOIL PROPERTIES AND
NUTRIENT LOSSES 6
SUMMARY 8
SECTION II MATERIALS AND METHODS 10
LEVELS OF RESEARCH 10
Experimental Design 10
Treatment Preparation 10
Analytical Procedures 11
Rainfall Simulation Unit 11
Laboratory Runs LG1-LG4 (Level 1) 13
Laboratory Runs LB1-LB6 13
Laboratory Runs LBD1-LBD4 15
Residue Series Runs 15
FIELD EXPERIMENTS (Level 2) 15
Series FB1-FB2 17
FARM EXPERIMENTS (Level 3) 17
SUMMER RUNS 17
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SUMMER RUNS 17
SUMMER FARM RUNS, TX1, TX25, AX1-AX28 17
Sampling and Runoff Analysis Procedures 19
Procedure for Rainfall Simulation and Runoff Collection 19
SECTION III RESULTS 21
LABORATORY SERIES LG1-LG4 21
Flow Volume 21
Precipitation to Initiate Runoff 21
TP, TSP Concentration in Surface Runoff 23
TP, TSPLoad 23
FIELD SERIES FB1-FB2 26
Flow Volume 26
TP, TSP Concentration Surface Runoff 28
TP, TSP Load in Surface Runoff 28
LABORATORY SERIES LB1-LB6 31
Flow Volume 31
Precipitation to Initiate Runoff (PIR) 31
TP, TSP Concentrations in Surface Runoff 31
TP, TSP Load 34
LABORATORY SERIES LBD1-LBD4 36
NORMALIZED TP, TSP LOADS IN SURFACE RUNOFF 36
Series LG1-LG4 36
Series LB1-LB6 36
PARAMETER CORRELATIONS 40
VARIATIONS IN NUTRIENT CONCENTRATIONS IN
SURFACE RUNOFF WITHIN EVENTS 42
SURFACE RESIDUE SERIES (LRB1-LRB6) 42
SUMMER FARM RUNS , 51
SURFACE CONDITIONS AND THEIR EFFECT ON TP, TSP
LOADING 57
Drying Mechanisms 57
Series LED 57
Farm Series 62
SECTION IV DISCUSSION 66
APPLICATION RATE EFFECTS 66
Incorporation Effects 66
Factors Affecting Phosphorus Loading 72
Surface Condition and Drying Time 72
Precipitation to Initiate Runoff 73
Texture 73
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Aggregation 73
pH in Surface Runoff 73
Normalized Load 75
Changes in Nutrient Concentration within Events 75
WINTER CONDITIONS 75
Disposal of Manure on the Snowpack 75
SUMMARY 75
Drying Effect 75
Effect of Bedding 78
SECTION V FARM APPLICATIONS 79
TILLAGE-MANURE SYSTEMS 79
Current Practices 79
Development of Spreading Schedules 79
Management Periods 80
Special Rate/Incorporation Practices 80
Practical Implications 80
Short-term Storage 80
Tillage Rotation Systems 81
Manure-Soil Testing 81
Modified and Experimental Tillage Systems 81
Supporting Practices 82
Tillage-Residue System and the Development of Soil Frost 82
Mobile Evaluation Systems 82
Recommended Program Initiatives 83
Research Needs 83
SECTION VI CONCLUSIONS 84
BIBLIOGRAPHY 89
APPENDIX A
INFELTROMETER REVIEW AND EVALUATION 96
APPENDIX B
PWSI OPERATING CHARACTERISTICS AND PROCEDURES 101
111
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LIST OF FIGURES
No.
2.1 - Schematic of PWSI unit [[[ 14
3.1 - Runoff volume, by rate, series Igl-lg4 ....................................... 22
3.2 - Runoff volume, by depth, series Igl-lg4 ..................................... 22
3.3 - Precipitation to initiate runoff, rate, Igl-lg4 .................................. 22
3.4 - Precipitation to initiate runoff, by depth, Igl-lg4 ............................. 23
3.5 - TP Concentration, by rate, series Igl-lg4 .................................... 24
3.6 - TP Concentration, by depth, series Igl-lg4 .................................. 24
3.7 - TSP Concentration, by rate, series Igl-lg4 ................................... 24
3.8 - TSP Concentration, by depth, series Igl-lg4 ................................. 24
3.9 - TP Load (mg), by rate, Igl-lg4 ................................................ 25
3.10 - TPLoad(mg), by depth, Igl-lg4 ............................................. 25
3.11 - TSP Load (mg), by rate, Igl-lg4 ............................................... 25
3.12 - TSP load (mg), by depth, Igl-lg4 ............................................. 25
3.13 - Runoff Volume, by rate fbl-fb2 ............................................... 27
3.14 - Runoff Volume, by depth, fbl-fb2.'. ......................................... 27
3.15 - TP, Concentration by rate, fbl-fb2 ............................................ 27
3.16 - TP Concentration by depth, fbl-fb2 .......................................... 27
3.17 - TSP Concentration by rate, fbl-fb2 ........................................... 29
3.18 - TSP Concentration by depth, fbl-fb2 ........................................ 29
3.19 - TP Load (mg), by rate, fbl-fb2 ............................................... 29
3.20 - TP Load (mg), by depth, fbl-fb2 ............................................. 29
3.21 - TSP Load (mg), by rate, fbl-fb2 .............................................. 30
3.22 - TSP Load (mg), by depth, fbl-fb2 ........................................... 30
3.23 - Runoff Volume by rate, Ibl-lb6 ............................................... 32
3.24 - Runoff Volume by depth, Ibl-lb6 ............................................. 32
3.25 - Precipitation to initiate runoff, series Ibl-lb6 ................................ 33
3.26 - TPLoad(mg), by rate, series Ibl-lb6 ........................................ 33
3.27 - TP Load (mg),by depth, series Ibl-lb6 ....................................... 35
3.28 - TSP Load (mg), by rate series Ibl-lb6 ....................................... 35
3.29 - TSP Load (mg), by depth, series Ibl-lb6 ..................................... 37
3.30 - Flow volume for different drying times, Ibdl-lbd4 ......................... 37
3.31 - Normalized TP Load (mg/kg), by rate, Igl-lg4 .............................. 38
3.32 - Normalized TP Load (mg/kg), by depth, Igl-lg4 ........................... 38
3.33 - Normalized TSP Load (mg/kg), by rate, Igl-lg4 ............................ 38
3.34 - Normalized TSP Load (mg/kg), by depth, Igl-lg4 .......................... 38
3.35 - Normalized TP Load (mg/kg), by rate, Ibl-lb6 .............................. 39
3.36 - Normalized TP Load (mg/kg), by depth, Ibl-lb6 ........................... 39
3.37 -- Normalized TSP Load (mg/kg), by rate, Ibl-lb6 ............................ 41
3.38 - Normalized TSP Load (mg/kg), by depth, Ibl-lb6 .......................... 41
3.39 - TP Concentration, by sequence, series fbl-fb2 ............................. 43
3.40 - TP Concentration, by sequence, series Ibl-lb3 .............................. 43
3.41 - TSP Concentration (mg/1), by sequence, series fbl-ft>2 .................... 44
3.42 - TSP Concentration (mg/1), by sequence, series Ibl-lb3 .................... 44
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3.44 - Loading Parameters by time, residue series.. 45
3.45 - TP (mg/1), by time, residue series 46
3.46 - Loading Parameters vs. Cover, all 46
3.47 - TP Loading Parameters vs. Rate 47
3.48 - TSP (mg/1) vs. Application Rate 47
3.49 - TSP (mg/1) vs. Residue Cover 49
3.50 - Mean Moisture Retention for Wet-Dry Cycles 49
3.51 - Water Retention, by trough, LED '. 50
3.52 - Normalized TP, TSP Loads, residue series 50
3.53 - Loading Parameters, farm series 52
3.54 - PIR, farming series 52
3.55 - Normalized TP, TSP, Farm Series 53
3.56 - Loading Parameters vs. Tillage 53
3.57 - TP, TSP Load vs. Tillage 54
3.58 - Loading Parameters vs. Crop 54
3.59 - TP, TSP Load vs. Crop 55
3.60 - Loading Parameters vs. Soil Type 55
3.61 - TP, TSP Load vs. Soil Type 56
3.62 - Suspended Solids vs. Residue Level 56
3.63 - TP vs. TSP Concentration, farm series 56
3.64 - TP Load vs. TSP Load, farm series 56
3.65 - Moisture Absorbing Capacities of Bedding Materials 58
3.66 - Manure Drying Curves, 50 hrs 58
3.67 - Manure Drying Curves 59
3.68 - Trough Moisture Content (%) 59
3.69 - PIR.SeriesLBD 60
3.70 - Normalized Load, by rate, farm series 60
3.71 - Normalized Load, farm series 61
3.72 - pHvs.Rate 61
3.73 - Surface Loading, farm series 63
3.74 - PIR, Surface Applications, Farm Series 63
3.75 - TP vs. TSP, Farm Series 64
3.76 - TP, TSP Loading vs. rate, farm series 65
3.77 - TP Load vs. TSP Load, farm series 65
4.1 - Mean Runoff Volume, by rate, all series 67
4.2 - Mean TP Concentration, by rate, all series 67
4.3 - Mean TSP Concentration, by rate, all series 68
4.4 - Mean TP Load, by rate, all series 68
4.5 - TSP Load, by rate, all series 69
4.6 - Mean Runoff Volume, by depth, all services 69
4.7 - Mean TP Concentration, by depth, all series 70
4.8 - Mean TSP Concentration, by depth, all series 70
4.9 - Mean TP Load, by depth, all series 71
4.10 - Mean TSP Load, by fepth, all series 71
4.11 - PIR, by rate, per unit area, all series ,. 74
4.12 - PIR, by depth, per unit area, all series '. 74
4.13 - Composite TP Concentration, by sequence, all series 76
4.14 - Composite TSP Concentration, by sequence, all series 76
4.15 - Composite TKN Concentration, by sequence, all series 77
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LIST OF TABLES
Page
No.
2.1 - Overview of Level 1,2, and 3 Investigations 12
2.2 - Residue Series Runs 16
2.3 - Farm Series Runs, 1986 18
2.4 - Laboratory and Farm Drying Runs 18
VI
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SYMBOLS AND TERMS
kg/ha/yr
MT/ha
TP
TSP
Load
Flow
C/N
P
N
NH3
ON
TKN
VS
rate
depth
Hg
mL
g
mg
SS
PWSI
LGX
LBX
FBX
AOV
PIR
Normalized
Nutrient
kilograms per heactare per year
metric tonnes per heactare
total phosphorus
total soluble phosphorus
mass
runoff volume
carbon to nitrogen ratio
phosphorus
nitrogen
ammonia nitrogen
organic nitrogen
total kjeldahl nitrogen
volatile solids
manure application rate
depth of manure incorporation
mercury
milliliters
gram
milligrams
suspended solids
Purdue-Wisconsin Sprinkling Infiltrometer
laboratory series utilizing Genesee silt loam, X-run number
laboratory series utilizing Bath silt loam, X-run number
field series utilizing Bath silt loam, X-run number
analysis of variance
precipitation to initiate runoff
load conversion based on unit manure application
nitrogen and phosphorus
vn
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SECTION I
INTRODUCTION
BACKGROUND
The application of manure to cropland has been a valued source of plant nutrients
for centuries. Tunney (1978) estimated that, on a worldwide basis, more nitrogen and
phosphorus are made available from manure production than are applied through inorganic
forms. Improvements in soil aggregation, tilth, surface permeability and water holding
capacity are also associated with manure applications to soil.
Although once an essential resource in farm fertility management, animal manures
are now often considered a waste product to be disposed of in the least costly manner.
Until the late nineteenth century, agriculture depended almost exclusively on animal
manures and legumes as nutrient sources to maintain crop yields (Stewart, 1980). The
availability of inexpensive inorganic nutrients and their relative advantages in handling and
application have intensified manure disposal problems. Increased herd size and
confinement coupled with decreased reliance on foraging have further encouraged
agricultural technologies which do not include efficient utilization of livestock manures.
Where poor management and inefficient utilization of manurial nutrients are evident,
contamination of surface and groundwater is possible. In particular, impoundments
subjected to accelerated nutrient loading can become eutrophic. The subsequent
degradation of water quality can impair drinking water supplies, survival of fish and other
aquatic species, and recreational water uses.
During the past decade tillage technology has evolved rapidly. This trend has
resulted in systems which minimally disrupt the soil while substituting chemical weed and
insect control. Currently over 30% of the nation's cropland is in some form of reduced
tillage (USDA, 1985). This level is approximately three to four times the 1975 level.
USDA projections indicate that this trend is likely to continue through the 1990s.
New York farmers have not adopted reduced tillage systems as rapidly as other
states. However, the area of cropland under reduced tillage has increased from 800 ha in
1980 to 130,000 ha in 1985 which accounts for about 13.5% of the state's cropland (SCS,
1985).
OBJECTIVES
The disposal of livestock waste on soil within the context of reduced tillage systems
imparts an additional dimension to potential nutrient losses from cropland. Manure
application rate, incorporation depth, method of incorporation, location and time, can all
potentially influence nutrient loads in surface runoff. To begin identifying which variables
are most important in the loss of phosphorus from manure spread cropland, a series of
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experiments were designed. The objectives of the laboratory and field experiments
conducted during the 29-month period of study are the following:
1. To observe total phosphorus (TP) and total soluble phosphorus (TSP)
concentration and load changes in surface runoff for different manure
application rates and depths of incorporation
2. To observe changes in TP, TSP concentrations and loads over time
3. To utilize the above results (1 and 2) as a basis for estimating the effect of tillage
on the incorporation of manure and subsequently the effect of tillage on TP,
TSP loads
4. To utilize the above results (1,2 and 3) to identify tillage-manure systems
which are likely to reduce TP, TSP loads from cropland
REVIEW OF RELATED RESEARCH
To accomplish study objectives and benefit from related research efforts, the
following literature review accessed two extensive data bases; the Commonwealth
Agricultural Bureau (CAB, 1984) and the Computerized Agricultural Information Network
(CAIN, 1984). Key words were organized to extract information on the effect of manure
applications and tillage on the hydrologic response and associated phosphorus losses from
agricultural soils.
NUTRIENT LOSSES FROM AGRICULTURAL AREAS
The fact that phosphorus has been identified as the h'miting nutrient in most lake
eutrophication processes has initiated a considerable body of research directed toward the
effect of tillage on phosphorus losses from cropland. Logan and Adams (1981) have
assessed loading data from all monitored U.S. tributaries draining into Lake Erie. They
estimate that 30% of the total tributary load is sediment bound and that 70% of the nonpoint
phosphorus load originates from cropland.
Logan and Adams (1981) conclude (from work accomplished by other researchers)
that the equilibrium phosphorus concentration of the top few centimeters of soil under a no-
till system would be higher than that under conventional tillage. Oloya and Logan (1980)
and Romkens etal (1973) have shown increased accumulation of no-till fields of
phosphates at the surface of no-till fields resulting in a relatively high level of soluble
phosphorus in surface flow. Barisas ctal (1981) evaluated conservation tillage practices
for nutrient control from cropland. They concluded that conservation tillage was not as
effective in reducing losses of nutrients in the dissolved phase. However, they did indicate
that conservation tillage would decrease total nutrient load by reducing the losses of the
sediment bound fraction.
Logan and Adams (1981) point out that fertilizer practices can influence nutrient
concentration in runoff, as demonstrated by several researchers (Romkens and Nelson,
1974; Oloya and Ixjgan, 1980, Baker and Laflen, 1981 and McDowel ctal 1980). The
interaction of phosphorus fertilizers with the soil are complex and dynamic. Although
much of the fertilizer phosphorus (P) applied is 100% water soluble at the time of
application, only 10-20% of the fertilizer P remains available with much of the initial
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application being quickly converted to highly insoluble precipitates of P. A fraction of the
fertilizer P applied becomes sorbed to soil surfaces and remains available for plant growth,
while some is lost in runoff if soil conditions are favorable. Despite this partitioning
between soluble and insoluble forms of P, a significant correlation between soluble P
concentration in runoff and extractable P associated with soil particles was observed.
SEASONAL DIFFERENCES IN NUTRIENT LOAD FROM MANURED CROPLAND
Converse etal (1975) compared yearly losses to seasonal losses from manured
plots. Over three years no significant differences in nitrogen or phosphorus losses were
observed. Runoff volume, however, was consistently less from the fall manured plots
than from the winter or spring applications.
In the third year of a study by Young and Mutchler (1976), increased nutrient flux
was observed from the spring manured plots. Heavy spring rains which occurred during
the snowmelt period and acted on the exposed spring application were associated with
accelerated loss of nutrients in surface runoff.
Hensler glal (1970), Young and Holt (1974), Klausner ejLal (1976) and Steenhuis
gtal (1977), examined nutrient losses occurring during snowmelt/rainfall runoff events.
Both Klausner etal (1976) and McCaskey etal (1971) varied die application rate in order to
evaluate the effect of manure loading rate on nutrient load in runoff. Long etal (1979)
spread dry dairy manure on the surface of fields during five different periods in a year.
Muck etal (1975) studied the influence of flow rate on nutrient concentrations using
poultry manure. Results of all of these studies indicate that nutrient load in surface runoff
is strongly influenced by the time between manure application and runoff events. The
conditions which induce these events can be snowmelt, precipitation or both. Hensler etal
(1970) applied manure during the winter over a two-year period. During the first year
nutrient losses from the manured plots were six times that of the control plots. In the
second year, losses from manured and control plots were similar with a slightly lower flux
from the manured plots. These contradictory results were explained by examining the
precipitation patterns for the two-year monitoring period. Within 24 hours after manure
was applied the first year, warm temperatures induced snowmelt and a 1.9 cm precipitation
event greatly enhanced losses. During the second year, similar events did not occur
combined with a generally lower level of precipitation.
Steenhuis etal (1977) studied winter spreading of manure under two sets of
conditions. On one group of plots, manure was applied on frozen ground in late January,
snow was allowed to accumulate, and runoff losses were measured during the snowmelt
events in late February. On the other group of plots, manure was applied on 0.6 cm of ice
resulting from sleet in early March. More snow and sleet accumulated and runoff was
monitored until the melt was completed in mid-March. Nutrient losses from these later
plots were 20-30 times greater than those of the corresponding control plots while the
January application resulted in losses which were considerably less.
Although the above studies demonstrate elevated nutrient load during thaw periods,
a number of field studies have reported small differences between the manured and
unmanured cases. Young etal (1977) measured nitrogen loads from manured plots for
three years. Runoff volume from the manured plots was less than from the corresponding
control plots, while phosphorus losses were slightly higher. Converse etal (1975)
recorded total nitrogen, inorganic nitrogen and total soluble phosphorus in runoff from
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both control and manure treated plots. Although nutrient concentrations in runoff from
most manured plots were higher, total nitrogen and total phosphorus losses from the
manured plots were not significantly different than the losses from control plots. An
exception to these findings was that inorganic-N losses from the manured plots were found
to be significantly greater than the control plots.
McCaskey etal (1971) reported increased total -N, inorganic -N and TSP losses
from two plots and decreased losses from the third. Plots received 52.8,104.5 or 157.3
MT/ha of manure distributed over 45 weeks. The plots which received the greatest loading
exhibited a decreased nutrient loss rate per unit manure applied.
Although all of the above experiments were carried out on corn, alfalfa or grass
plots, few researchers compared the three. Young and Mutchler (1976) observed
snowmelt nutrient losses from corn and from alfalfa plots. Losses of nitrogen and
phosphorus from the manured alfalfa plots were considerably higher than those from the
manured corn plots. The authors reasoned that some of these differences were due to the
rougher surface of the corn plots which would accommodate more surface storage.
Young and Holt (1974) simulated a 12.7 cm, two-hour rainfall five days after a late
spring manure application. Nutrient flux from the manured plot was appreciably greater
than the flux from the control plots.
Klausner etal (1976) applied manure at annual rates of 16.5,49.5 and 99 MT/ha on
corn plots over a three-year period. The monitoring period was during late winter and early
spring. With one exception, losses from all plots measured less than 9.0 kg/ha and 3.5
kg/ha for inorganic nitrogen and TSP, respectively. However, during the first year of
monitoring the plot receiving 49.5 MT/ha of manure lost 51.7 kg/ha of inorganic -N and
9.9 kg/ha of TSP. This was the only time a plot was applied with manure while snow was
actively melting. During the last two years of the study, when all manure applications were
to frozen ground which was subsequently covered by snow, no appreciable difference in
nutrient load was observed between the three application rates.
SOME EFFECTS OF MANURE ON THE HYDROLOGIC AND NUTRIENT
PROPERTIES OF SOIL
The application of manure to soil alters the physical, chemical and biological
properties of the soil and soil environment The following elements of the literature review
emphasize a number of the physical changes in soil as a result of manure applications. A
number of the physical variables relate directly to the hydrologic response of manure
amended soils. These relationships in turn influence TP and TSP loading.
The Influence of Manure on Infiltration and Moisture Retention
The average water content of the fresh feces of a dairy cow, on a wet basis is 85-90
percent (Sobel, 1966). Physically this means, depending on application rate and
incorporation depth, that a relatively large quantity of water is applied to the surface or
mixed into the soil profile with each manure application.
The effect of soil manure amendments on soil water capacity has been researched
by Unger (1974). He studied the influence of feedlot wastes on various soil characteristics
including soil water holding capabilities. He reported that the effect of manure on pore size
and space appears to negate some of the benefits an increase in percent organic matter might
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have on field capacity. For the case of fresh manure applications, Unger (1974) concluded
that a net decrease in field capacity would result. Unger (1974) also reported that soil bulk
densities decreased with larger application rates due not only to an increase in percent
organic matter, but also to an increase in percent air space. This is supported by an
observed increase in water content at the level of saturation.
Organic Matter Accumulation and Decomposition
A number of researchers who have looked at livestock waste disposal treat it as a
simple addition to the pool of organic matter in soil. Johnston (1980) reported on the long-
term monitoring of soil organic matter, concluding that changes in soil organic matter vary
directly with the quantity of organic matter added and the oxidation rate. VanDyk (1980)
and Sochtig and Sauerbeck (1980) studied how organic matter accumulation, degradation
and decomposition vary with soil properties and environmental conditions.
Several researchers have studied how organic matter contributes to the nutrient
status of soils. Johnston (1980) suggests that an important contribution of organic matter
is the stabilization of soil structure. In addition, he points out that increases in cation
exchange capacity and the release of nitrogen, phosphorus, sulfur and micronutrients
during oxidation of organic matter directly benefit plant growth. Climatic factors and
farming systems will circumscribe the short-term advantage of these processes. Dutil
(1980) points out the importance of the quality of organic amendments and their influence
on carbon to nitrogen (C/N) ratios in the short-term. He concludes that a buildup of
organic matter in the short-term will occur only if extremely large quantities of waste are
added. He cautions that this could depress crop yields unless sufficient quantities of
nitrogen are supplemented.
Newhould (1980) concluded that organic matter was the key influence on soil
structure in unstable soils. Similar to other investigators (Sauerbeck, 1982; Parvlson and
Jenkinson, 1981), Newhould (1980) observed small changes in organic carbon levels as a
result of farming practices. After 60 years of continuous cultivation, organic carbon levels
typically changed less than one percent. Although McGrath (1980) observed larger
changes in organic carbon content for continuously farmed plots, he demonstrated that
much of the difference can be attributed to the redistribution of organic matter when a
grassland soil is tilled,
The Influence of Soil Moisture
The influence of crop system, tillage and manure amendments on soil moisture have
been documented by several investigators. Jovanove and Veskove (1974) reported that
stable manure treatments affected soil moisture more than plant residues. Kuipers (1982)
documents a 30% increase in surface storage with tillage methods which left a roughened
surface. Kuipers (1980) also observed an increase in infiltration rate at moderate rainfall
intensities. Davies (1980) concluded that moisture retention properties of no-tilled soils in
the short-term are related to their ability to retain sufficient coarse porosity at the surface.
Larson (1980) documented the advantages of surface infiltration when residues are present.
Sarkan etal (1973) observed increases in hydraulic conductivity, percent saturation
and a decrease in the percent of soil dispersion associated with manure applications.
Biswas and Khasla (1971), Long etal (1975), and Mazurak etal (1955) recorded changes
in soil-water intake and storage as a result of manurial soil amendments. Mazurak etal
(1955) noted that the rate of water intake for manured row crops was nearly twice the rate
of the unmanured plots.
-------
Soil Management and Nutrient Availability, Retention and Losses
Several investigators have studied the influence of farming practices on the
decomposition rates, availability and losses of nutrients in the soft profile. Sauerbeck
(1980) found that the addition of nitrogen to the soil in the fall had little effect on
decomposition rates. He also observed that a combination of straw and inter-cropping are
likely to approach the effect of farmyard manure alone. Both Sauerbeck (1980) and Davis
(1980) concluded that despite different soil treatments and cropping systems, soil humus
content will likely approach an equilibrium value. Sauerbeck (1980) suggests that humus
conservation should not be an objective of farming systems unless it is proven that a
particular system drastically decreases soil organic matter over a long period. Sauerbeck
(1982) concludes that erosion of soil organic matter and humus (decomposed organic
matter) on steep slopes probably has a larger effect on soil humus levels than crop rotations
or manurial treatments.
Kafoed (1982) stresses the importance of soil humus in retaining water and plant
nutrients and for buffering changes. Sauerbeck (1982) also speculates that the value of the
highly degradable fraction of manure is more important than previously thought. He points
out that the benefits include intermediate products of decomposition and microbial turnover.
Aggregate size distribution and water stability were measured by Katcheson etal
(1979). They observed that soil aggregates less than 5 mm in size favored corn growth on
a well-drained silt loam soil. Fall moldboard plus four spring tillage operations resulted in
higher corn yields than either full chisel or no-till. They attributed tillage advantages to the
lower penetration resistance of the moldboard system.
Romkens etal (1973) compared the nutrient control effectiveness of various tillage
methods. He concludes that most of the nutrient losses from cropland are associated with
enriched colloidal particles and the tillage system which controls this fraction will be the
most effective control practice.
THE EFFECT OF TILLAGE ON SOIL PROPERTIES AND NUTRIENT LOSSES
Many investigators have studied the influence of manure amendments and tillage on
soil structure. Unlike organic matter levels, soil structure is changing constantly under the
influence of mechanical forces and water flux induced by precipitation, evaporation,
freezing, thawing, stage of crop growth, and farming methods (Kafoed, 1980).
Fawcett (1978) related changes in water accumulation to cone penetrometer
measurements. He derived a linear relationship between the log of available water and the
force required for cone penetration. Marston and Herd (1978) relate that clay content may
be more critical than organic matter in maintaining aggregate stability in heavy clay soils.
Osborne etal (1970) reported that bulk density of the surface 0-10 cm was significantly
increased by all cultivation treatments. They relate that the permeability of the soils they
tested was strongly correlated to the degree of aggregation. In turn the bulk density was
significantly related to penetrometer readings. Russell (1978) stresses the importance of
roots on soil structure. He also observed that pore size decreased with increasing bulk
density.
-------
Pidgeon and Soane (1978) demonstrated that bulk density responses to tillage
systems varied with soil type while cone resistance measurements did not. Over a ten-year
period, Pidgeon and Soane (1978) monitored the following tillage practices:
deep moldboard plow (30-35 cm)
normal moldboard (18-23 cm)
chisel plow (3 passes, variable depth, 15-25 cm)
zero tillage.
Cone resistance was found to be more closely linked to tillage and traffic than cropping
systems. In addition, they noted that bulk density measurements alone do not correlate
well with crop performance. Finally Pidgeon and Soane (1978) observed no significant
increase in bulk density with zero tillage at any depth below 6 cm. In later work Soane
(1980) documents soil degradation attributable to compaction under wheels and suggests
control options.
Boels (1980) describes how density profiles reflect a certain equilibrium state
between soil manipulation and bulk density. Boels (1980) relates work done by others
which define a critical bulk density profile. This profile is an equilibrium state between
bulk density and the average loading by farm machinery on non-cemented soils. This
concept also suggests that loosening of soils with densities less than the critical value have
to be repeated to keep the soil friable.
Herbert (1982) has described several types of soil degradation related to the organic
matter level of soils. Soil compaction and elasticity appear closely related to organic matter
levels. VanDyk (1980) and Sochtig and Sauerbeck (1980) have attempted to model the
buildup and degradation of soil organic matter for different farming systems. Canarache
(1979) developed an agrophysical index to reflect changes in soil structure. The index
represents the arithmetic mean of ten individual physical properties.
Utomo and Dexter (1981a, 1981b, 1981c, 1981d) have studied several aspects of
soil structure which provide insight into the possible consequences of different manure-
tillage systems. On a sandy loam, Utomo and Dexter (198la) observed that the amplitude
of soil water content fluctuation increased with tillage. As a consequence, a decrease in
clod strength, termed 'tilth mellowing' was noted. In another set of experiments on a
sandy loam, Utomo and Dexter (1981b) found that variations in soil friability (soil
structures) are closely related to soil water content. They confirmed that sandy loams are
most friable at water contents approximately equal to their casagrande plastic limits. Utomo
and Dexter (1981c) increased friability through wetting and drying cycles, freeze/thaw
cycles and phosphoric acid treatments. Utomo and Dexter (1981d) also investigated the
'age hardening' of top soils. The term 'age hardening' is used to characterize the change in
the strength of a remolded soil sample at a constant water content. They observed that
water stable aggregates increased with aging after tillage disturbances. The degree of
decomposition and organic matter levels strongly influenced aggregate formation.
The effect of tillage on nutrient losses from manured cropland was studied by
Mueller (1979). The manure application rates he used varied from 22-56 MT/ha. Mueller
(1979) concluded that the soluble phosphorus load in surface runoff increased with no-till
systems while sediment bound phosphorus decreased.
-------
Mueller (1979) also investigated some of the changes in soil characteristics and
moisture retention for conventional, chisel and no-till plots both with and without manure.
His work indicates that infiltration increased initially with all tillage systems. This effect
diminished over time with no-till systems eventually showing better hydrologic
characteristics. Mueller (1979) also points out that the chisel plow systems increased
surface storage significantly more than the other tillage systems studied. Over the entire
period of study Mueller (1979) concluded that no-till is more effective in reducing runoff
on well-drained soils than any of the tillage systems investigated.
In Mueller's (1979) study the volume of runoff collected from early spring events
on plots where manure had been spread on the surface did not result in the high runoff rates
reported by some investigators. Converse etal (1974), Young and Mutchler (1975), and
Baker etal (1981) have shown snowmelt runoff, soil losses and TP losses were lower for
manure amended soils than for plots not treated with manure. These researchers explain
some of their findings by suggesting that manure protects the surface as a mulch cover.
Although Mueller (1979) concludes that TP losses were reduced substantially from
manured plots, losses of soluble phosphorus increased significantly. For reduced tillage
systems to be effective in controlling soil loss, Mueller (1979) concludes that there must be
some residue left on the surface and field operations must be performed across the slope.
SUMMARY
There have been few investigations which have studied the effect of tillage systems
on phosphorus losses from manured cropland directly. However, pertinent and helpful
information was obtained from two types of studies:
the influence of livestock manure applications on the hydrologic and nutrient
properties of agricultural soils.
the effect of tillage on nutrient availability and losses.
Some general conclusions can be drawn from the above literature review:
An accumulation of phosphorus at the soil surface has been observed for no-till
cropland.
Elevated losses of water soluble nutrients have been observed for no-till fields.
The availability of phosphorus for loss in surface runoff is strongly influenced
by organic matter content of the soil, pH and soil structure.
Relatively high losses of phosphorus from manure-spread cropland are typically
associated with surface applications.
In most cases, manure which is applied to the soil is incorporated into a relatively
large pool of organic matter. Soil treatments and cropping systems are likely to
have little effect on the equilibrium organic matter level of most agricultural soils.
The organic matter status of soil appears to reach a long-term equilibrium which
is a function of climate and soil texture. Thus, manure applications are only one
variable, in most instances having only a subtle effect on long-term equilibrium.
Tillage complements manure amendments in the short-term by increasing
porosity, decreasing bulk density and resistance and redistributing organic matter
in the soil profile.
The benefits of soil tillage are typically followed by soil consolidation and
compaction with an associated negative impact on soil hydrologic properties and
-------
nutrient availability potential. Soil compaction is a penalty associated with many
tillage systems.
Since most phosphorus lost from cropland is sediment bound, plant residues are
an effective method of reducing total phosphorus load.
-------
SECTION II
MATERIALS AND METHODS
LEVELS OF RESEARCH
Three important questions posed by the project objectives were the extent to which
manure application rate, incorporation depth and time of application affected TP and TSP
loads in surface runoff. In order to establish experimental control and comparison of the
rate/depth/time variables, a series of laboratory (level 1) and field experiments (level 2)
were undertaken. The results of level 1 and 2 experiments were then used to evaluate the
effectiveness of various tillage - manure systems to decrease phosphorus losses (level 3).
In all cases, the design of laboratory experiments were intended to provide more controlled
observations of the rate/depth/time effects. Field plots allowed a more realistic comparison
of the twelve manure rate and depth combinations on cropland. Farm runs (level 3)
provided both general and practical applications of level 1 and level 2 findings in the
context of a farm manure spreading program. Table 2.1 provides an overview of the three
levels of investigation.
Experimental Design
Twelve cases (three manure application rates and four depths of incorporation) were
established for series LG1-LG4. The range of application rate (22-135 MT/ha) and
incorporation depth (0-15 cm) were intended to reflect realistic combinations of rate and
depth which could be achieved by various tillage systems. One control trough was
maintained.
The time interval between runs was chosen to reflect differences in runoff potential
due to drying of the soil-manure pack. The initial run, LG1, was conducted on the
untreated silt loam while run LG2 was completed two days later, immediately after manure
application. The troughs were then covered for 44 days to allow a slow but complete
drying of the soil-manure pack before the next run, LG3. By covering the troughs with a
plywood foam rubber lid, cracking and separation of the soil-manure mixture from the side
walls of the trough was avoided. A shorter period of time, 10 days, elapsed between LG3
and LG4 runs. The purpose of LG4 was to observe runoff volume and TP, TSP
concentrations after the soil manure mixture had dried and had been rewetted.
Treatment Preparations
A Genesee silt loam soil was chosen for the first set of laboratory runs. It is a well
drained, medium textured alluvial soil derived from glacial drift that is high to medium in
lime content. There is typically a 4-6% accumulation of organic matter in the surface layer.
The Genesee silt loam exhibits good water holding capacity, is well aerated and usually has
a good supply of phosphorus and potassium (Soil Survey, 1981). The silt loam soil was
air dried and sieved through a No. 4 standard sieve to eliminate large stones and
aggregates.
Thirteen troughs (20 cm x 15 cm x 100 cm) were constructed of 10 gauge stainless
steel. Each trough was fitted with one inch angle iron frames and 22 cm x 17 cm sheet
metal end plates. Rubber gaskets and silicon caulk were used to provide a watertight seal at
each trough end.
Each trough was equipped with a 1.90 cm tygon drainage tube placed at the center
bottom of one side. A 60 mesh screen was placed over the tube to prevent the washing of
10
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sand. The end plates provided sufficient flange width for a dolly to be inserted under the
trough for transport between rainfall simulation runs, weighing operations and storage.
Five centimeters of No. 3 coarse sand was added to the bottom of each trough.
Fifteen centimeters of air dried soil were then added to each trough. Weights were
recorded at each stage using a 112 kg How top loading scale.
Following one half hour rainfall simulation runs manure treatments were
completed. Troughs 1,2 and 3 had a mixing depth of 15 cm. Troughs 4,5 and 6 had a
mixing depth of 10 cm. Manure was mixed to a depth of 3 cm for troughs 7, 8 and 9. For
troughs 10, 11 and 12 manure was applied to the surface. Three application rates were
used corresponding to 135., 67. and 22. Mt/ha. Troughs 1, 4,7 and 10 received heavy
applications. Troughs 2,5, 8, and 11 received the moderate rates while 3,6,9, and 12
received low rates. Trough 13 remained untreated.
The mixing of the manure with the soil was accomplished outside of the troughs.
Manure quantities were weighed on a Pennsylvania 5 kg. triple beam scale. Soil was
excavated with a trowel to the required depth. Manure and soil were then thoroughly
mixed with a trowel on a sheet of plastic and refilled into the trough. There was no attempt
to pack the trough to achieve a specific bulk density.
Runoff was collected continuously from the plot surface by means of the perforated
copper collection tee under a vacuum pressure which typically varied between 60 and 90
mm of Hg. Samples were collected from this flow through a sampling shunt at specific
time intervals, predetermined for each run. Each sample was collected in a 490 ml plastic
bottle.
Analytical Procedures
pH and suspended solids analyses (SS) were conducted in the soil and water
laboratory at Cornell University. An Orion model 407A pH meter was used for the pH
analyses. The method of analysis (150.1) is described in EPA (1979). Suspended solids
determinations were made by the filtration of 100 mL of sample through tared 4.5 cm glass
fibre Whatman filter followed by drying at 105°C in a Thelco Model 18 oven. A Mettler
PI000 analytical balance was used for all SS weight determinations.
Unfiltered and filtered samples of runoff were allocated to 125-mL Nalgene
containers which had been acidified with 5N H2SO4. Filtrations through 0.45^1 Millipore
filters under a vacuum pressure of 10 psi or less were used to define the soluble
phosphorus fraction. All samples were frozen and sent air freight in iced coolers to the
Center for Laboratories and Research (CLR), New York State Department of Health where
the TP, TSP analyses were performed. The CLR procedures for TP and TSP
determination utilize a persulfate digestion in acid medium procedure (365.2), described in
EPA (1979).
Rainfall Simulator Unit
An important element of the methods used for investigation was the choice of a
technique which would eliminate much of the variability between precipitation events. This
variability often masks differences in loading between treatments. In addition, the myriad
of manure-tillage systems possible made it advantageous to look for a mobile unit capable
of short-term field evaluations. To accomplish project objectives and collect both
laboratory and field data a rainfall simulator was utilized.
11
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Advantages in using the simulator were:
controlled laboratory conditions could be established to formulate more precise
treatments
a greater number of rate-depth options could be investigated in the field
consistency between field and laboratory observations could be achieved
allowing more valid comparisons
precipitation characteristics are more precisely defined and therefore can be
varied as needed for sensitivity analyses.
TABLE 2.1
OVERVIEW OF LEVEL 1, 2, AND 3 INVESTIGATIONS
Series
LG1-LG4
LB1-LB6
LBD1-LBD4
LRB1-LRB6
FB1-FG3
WB1-WB5
TX1-TX2D
AX1-AX28
Level
1
Description
Application rate, incorporation depth
variables for extreme wet/dry cycles
(laboratory)
Application rate, incorporation depth
variables for specific time intervals
(laboratory)
Surface applications, drying variables
for specific time intervals (laboratory)
Residue cover and manure application
rate variables for specific time intervals
(laboratory)
Application rate, incorporation.depth
variables for field conditions (field)
Passive winter collection of runoff for
silt loam soil. Application rate,
incorporation depth, residue cover, soil
type, crop, and tillage method as
variables (field)
Farm runs with different manure
application rates, residue cover, tillage
method and crop (Oswego County)
Farm runs with different manure
application rates, residue cover, tillage
method, crop and soil type (Wayne
County)
12
-------
A literature review was conducted to compare the types of rainfall simulators
available. A summary of this review is presented in Appendix \. The principle criteria in
choosing a simulator were:
mobility - A simulator which could be transported from the soil and water
laboratory at Cornell University to various farm locations within about a 100
mile radius
rainfall characteristics - Intensity, drop size, drop velocity, uniformity of
application and kinetic energy characteristics should be comparable to natural
rainfall
' documented field experience - Utilization of the simulator by other investigators
would provide valuable information with respect to other field applications and
the comparison of results of similar studies.
A modified Purdue Sprinkling Infiltrometer (PWSI) (Bertrand and Parr, 1961) was
used for precipitation simulation runs. Since the principal modifications were made by
Dixon and Peterson (1964, 1968) at the University of Wisconsin, the rainfall simulation
unit will be referenced as a Purdue Wisconsin Sprinkling Infiltrometer in this report.
The PWSI unit was used to generate and collect both laboratory and field runoff
samples for the manure treatments cited earlier. A schematic representation of the PWSI
unit is given in Figure 2.1. Component details and operating procedures are provided in
Appendix B.
The Spraying Systems 7LA nozzle was selected by Bertrand and Parr (1963)
because the range of droplet sizes were comparable to those reported by Laws and Parsons
(1943) for a>natural rainfall event. In addition, the uniformity of application,over the 1.35
m2 field plot area was the best of the more than 20 nozzles evaluated. Finally, the desired
intensity of application could be achieved with relatively low operating line pressures (5-10
psi). A more complete description of the PWSI unit, operating characteristics and
procedures are provided in Appendix B.
Since over 300 runs were completed using the PWSI unit, an excellent opportunity
existed to evaluate its design and operating characteristics as a result of this extensive
experience. Possible modifications and improvements were documented. This information
is included in Appendix A.
Laboratory Runs LG1-LG4
The first series of laboratory runs consisted of a 30-minute pre-treatment (series
LG1) followed by three 60-minute runs with the manure treated soil. Appendix B
summarizes the procedures used during simulated precipitation events in the laboratory.
Laboratory Runs LB1-LB6
Laboratory series LB1-LB6 utilized the channery Bath soils of field series FB1-
FB2. Unlike series LG1-LG4, coarse aggregates and stones were not sieved. The
experimental design of series LB1-LB6 provides more frequent observations of TP and
TSP losses for high manure application rates at incorporation depths of 15, 10, 3 and 0 cm,
respectively. A trough with a low application rate to the surface and an untreated trough
were maintained during series LB1-LB6. Series LBl-LB6.provided additional details
13
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^ Water Supply
Tank
r Bypass
\ Valve
Inlet
Screen
Nozzle
Pump
Pressure
Gage
V
vti
Vacuum Pump
, Pressure
Tank
Plot
Frame
FWI Level
Recorder
Pressure
Gages
Spray
Nozzle
* » .
Runoff Collection Tank
Perforated
Collection T
Figure 2.1
Schematic of PWSI Unit
-------
defining TP, TSP load changes occurring as a result of more frequent wetting of the soil-
manure mixture.
The second series of laboratory runs was conducted with a channery Bath silt loam.
This soil was collected from an area adjacent to the field plots (FB series). The well
drained Bath soil is typically acidic. The top 20-30 cm tend to be a dark-grayish brown silt
loam containing many flat stone fragments. The plow layer is generally very porous and
well aerated allowing for good root development. The organic matter content of the plow
layer is commonly between 3-6% (Soil Survey, 1971).
Series LB1-LB6 involved high application rates at different incorporation depths. .
One trough was added to observe the special case of a relatively low application rate to the
surface while one trough remained untreated.
The procedure for laboratory rainfall simulation runs for series LB1-LB6 is the
same as series LG1-LG4 and is described in Appendix B.
Laboratory Runs LBD1-LBD4
The purpose of series LBD1-LBD4 was to provide data further specifying how
runoff volume changes with drying conditions for the special case of surface-applied
manure. This series was designed to provide information for the potentially high TP, TSP
losses associated with surface applications. In particular, the storage conditions of the
troughs were changed to allow for a relatively high drying rate compared with series LG1-
LG4 and LB 1-LB6 in which drying rates were purposely kept low. Thus, extremes in
drying rate and its likely influence on TP, TSP loading could be investigated, particularly
for the special case of surface applied manure.
The LBD1-LBD4 series all used heavy rate applications (135 MT/ha) to the surface
of an air dried Bath silt loam. No lid was placed over the troughs during storage as in
series LB1-LB6. The surface applied manure was allowed to dry for 2 days, 5 days, 10
days and 20 days before a standard precipitation run using the PWSI unit was completed.
Replicate troughs were prepared in each case and after the initial wetting each trough was
rewetted during the next run period.
The procedure for laboratory rainfall simulation runs for series LBD1-LBD4 was
the same as previous laboratory series runs and is described in Appendix B.
Residue Series Runs
TP and TSP loads were estimated for both residue cover and manure applications
over residue. The sequence of experiments is described in Table 2.2. An initial series of
runs (Rl) was conducted with an air-dried soil with no residue or manure cover. Two runs
with surface cover rates of 0,1, and 3 Mt/ha equivalent of dry corn stover on a Bath soil
were then completed. The final three runs reflect TP, TSP loading for manure applied over
the residue cover. Manure application rates for these simulated precipitation events were 0,
22 and 135 Mt/ha.
FIELD EXPERIMENTS (Level 2)
Cornell's EIDS project farm located 16 miles north of Ithaca, New York was
chosen for the field level of study. The watershed draining the farm flows to Fall Creek
and through the Finger Lakes tributary system ultimately discharging to Lake Ontario.
15
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Table 2.2 - Residue Series Runs
Runs***
Rl
R2
R3
R4
R5
R6
1
2
3
4
5
6
Res.
Res.
Res.
Res.
Res.
Res.
0*
0
0
0
0
0
Res.
Res.
Res.
Res.
Res.
Res.
1
2
1
0
1
0
Res.
Res.
Res.
Res.
Res.
Res.
1
2
1
0
1
0
Man.
Man.
Man.
Man.
Man.
Man.
1**
2
1
0
2
0
Man.
Man.
Man.
Man.
Man.
Man.
1
2
1
0
2
0
Man. 1
Man. 2
Man. 1
Man. 0
Man. 2
Man. 0
Time
Od
2d
7d
lid
13d
20 d
Applications
No
Res.
No
Man.
No
No
*Residue levels
Res 0 = 0 g
Res 1 = 41 g (dry)
Res 2 = 23 g (dry)
**Manure application levels
Man. 0 = 0kg
Man . 1 = 0.41 kg
Man . 2 = 2.48 kg
***Sample protocol
- Time interval 5 min., 15 min., and 25 min.
- All composite samples
- All subsurfaces flow collected and 1 composite
sample created
The purpose of the field series was twofold. First, validation of the high TP, TSP
loads associated with precipitation events which immediately followed manure application
was desired for the field case. Second, the likely changes in infiltration and runoff for the
undisturbed field soil as opposed to the disturbed trough samples required further
investigation.
16
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Eighteen permanently staked plots were established on a cornfield consisting
primarily of a Bath channery silt loam. The eighteen plots were established on the lower
slope of BIDS field #27. In addition to the 13 rate depth treatments used in the laboratory
series, five untreated plots were staked to establish control plots and an indication of the
heterogeneity of the soils in the area of the field where the runs were being made.
A 1.35 m2 steel frame was driven to a depth of 20 cm on each plot. Soil was
excavated to treatment depth and placed on sheets of plastic adjacent to the plot. Manure
and soil were then mixed within the plot area in layers such that a uniform distribution of
manure was achieved.
Series FB1-FB2
The first series of precipitation events (FBI) took place immediately after site and
treatment preparation. The second series (FB2) were completed approximately 24 hours
after FB1. Incorporation depths were the same with the exception of the maximum depth
which increased from 15 cm to 20 cm for the field series. This change was made to more
closely approximate depths of moldboard plowing and deep chiseling. A plywood lid was
placed over the plot frame during the 24 hours between simulated precipitation events FB 1
and FB2. A third set of simulation runs (FB3) were made the following spring to observe
long term changes in flow volume and TP, TSP concentration in surface runoff.
The procedure for each run was similar to the laboratory procedures described in
Appendix B with a few exceptions:
instead of transporting the troughs to the PWSI unit, the canopy/frame/nozzle
unit was erected over each plot
, an MF65 tractor was used to transport all equipment and the water supply tanks
unlike the laboratory troughs, the field plots were exposed to natural
precipitation events after the FB2 runs.
FARM EXPERMENTS (Level 3)
The objectives of level 2 studies were to look more closely at the special problems
associated with tillage-manure system design during the winter period. The sub-objectives
directly related to this question include:
the effects of surface residue on TP, TSP losses, particularly during the winter
period
field and farm observation of TP, TSP loads for different tillage, residue, crop
and soil type conditions
characterization of tillage-manure systems to decrease phosphorus losses during
the winter period.
SUMMER FARM RUNS
Summer Farm Runs TX1-TX25. AX1-AX28
The purpose of the summer farm runs was to extend initial laboratory and field
experiments to operating farms where the manure had been incorporated by tillage
implements. Two farms (one in Wayne County and one in Oswego County, New York)
cooperated for these runs. Specific phosphorus control options investigated were:
17
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incorporation with moldboard, chisel and no-till planting
a wide range of residue levels
a wide range of manure applications rates
inclusion of hayland
a wide range of soil types, including poorer drained soils.
Table 2.3 summarizes the specific tillage soil-treatment variables evaluated by the
simulated precipitation farm runs.
The hydrologic response and TP, TSP loading characteristics of manure amended
soils are greatly influenced by drying of the manure pack. This effect had been observed in
both laboratory and field experiments. The time and drying conditions between initial
manure application and the first precipitation event are particularly important.
Table 2.3 - Farm Series Runs, 1986
Series
TX1-TX7
TX8-TX15
TX16-TX17
TX18-TX21
TX22-TX23
AX24-AX28
AX29-AX34
Field Treatments
no-till
no-till
no-till
conventional
conventional
chisel
no-till
sou
silt loam
silt loam
silt loam
silt loam
silt loam
sandy loam
sandy loam
Variables
3 manure application rates
3 residue levels
fresh manure applications
to surface
fall manure applications
alfalfa cover
3 residue levels
3 residue levels
Series
AX35-AX36
AX37-AX41
AX42-AX48
Field Treatments
no-till
conventional
chisel
Soil Variables
clay loam alfalfa cover
clay loam fall manure applications
sandy loam fresh manure applications to
surface
Table 2.4 - Laboratory and Farm Drying Runs
gne
LED
Plots
135 mt/ha surface
135 mt/ha surface
135 mt/ha surface
Time
t = 2, 5, 10, 20 d
t = 5, 10, 20 d
t = 10, 20, d
18
-------
135 mt/ha surface t = 20 d
TX 135 mt/ha surface t = 4d
AX 225 mt/ha surface t = 4 d
135 mt/ha surface t = 4d
67 mt/ha surface t = 4 d
22 mt/ha surface t = 4 d
The LBD series specifically looked at flow volume, TP and TSP concentration
under controlled laboratory conditions. These experiments were repeated on farms A and
B in June, 1986. For these farm trials a period of four days between manure application
and simulated precipitation was allowed. Table 2.4 summarizes all laboratory and field
treatments.
The Purdue Wisconsin Sprinkling Infiltrometer (PWSI) was winterized to allow for
cold weather and spring thaw runs. These modifications included the following: all pipe
networks were provided with a sump and drain system. All piping was insulated and
wrapped in heat tape. Finally, all valves and flow control devices were protected from
freezing by insulation and drain sump systems.
Sampling and Runoff Analysis Procedures
Each runoff collection period is run for 60 minutes, with 10 being the time at
which precipitation is first applied to the plot.
One composite sample was collected for each run at intervals of
5 min., 20 min., 35 min., and 50 min. after runoff began.
Each sample was immediately refrigerated at 4°C.
pH, suspended solids and volatile solids were performed on each sample as
described in the quality assurance update.
Three composite samples (0-20 min., 20-40 min., and 40-60 min.) were
collected for a small sample of runs.
Approximately 50mL of sample was filtered through a 0.45[i filter for TSP
analysis at the Health Department Labs. Whole and reserve samples were
dispensed and sent to the Health Department Labs for TP analysis.
Procedure for Rainfall Simulation and Runoff Collection
The sprinkling infiltrometer was prepared for operation'by filling supply
reservoirs and connecting runoff collection tubes to vacuum tank.
The channels were covered with sheet metal lids during calibration runs
The infiltrometer was allowed to operate for five minutes before precipitation
calibration data is collected. During this period all valves and gauges were
checked to be sure system is in full operation.
Following the initial five minute period, a ten minute calibration run was made
where the nozzle discharge was directed through a 7.6 cm pipe to a collection
tank where the volume change over time was recorded.
After the calibration run the nozzle is allowed to discharge fully over the plot
area and the channel lids were removed for runoff collection runs.
19
-------
Initial time of precipitation was recorded.
Time to ponding was recorded.
Time to initial runoff collection was recorded.
Samples were collected at specific time intervals (varies with series, can be
individual or composite).
Sample bottle number and time were recorded.
At the end of the run, the supply valve was closed
Vacuum pump was allowed to collect remaining runoff.
Surface and subsurface samples were immediately refrigerated for later
preservation.
Trough was transported to storage (with lid cover).
After 24 hours trough was re-weighed.
Periodic re-weighing of trough and soil samples collected.
Level recorder strip charts reduced for flow rates and flow volumes.
20
-------
SECTION HI
RESULTS
LABORATORY SERIES LG1-LG4
The purpose of laboratory series LG1-LG4 was to observe changes in runoff
volume and phosphorus concentration for different application rates and depths of
incorporation. The time interval between simulated precipitation events was chosen to
represent differences in runoff potential and drying of the soil-manure mixtures. The
results of laboratory series LG1-LG4 were used to more precisely define the experimental
design of laboratory series LB1-LB6.
Flow Volume
Figures 3.1 and 3.2 indicate flow volume for three manure application rates and
four depths of incorporation (15,10, 3,0 cm) and one untreated trough for four
precipitation events over a 56-day period. Each observation represents the mean value for
the respective incorporation depth or application rate treatments of a specified rainfall
simulation event. As indicated in Figure 3.1, when precipitation occurred immediately after
manure application (series LG2,) surface flow volume was greater for the manure treated
soils compared with the untreated case. The application of manure to the soil surface
increased surface runoff by as much as 81% above the untreated case (Figure 3.2) when a
12 cm simulated rainfall event immediately followed manure application. The largest
surface runoff volume for an individual trough occurred for the high (135 MT/ha)
application rate to the surface.
After drying of the manure soil mixture, a third precipitation event was run (series
LG3). Surface runoff volumes (Figure 3.1 and 3.2) were reduced by as much as 89% for
the manure treated soils with the highest reduction for the trough with the 135 MT/ha
surface application.
The three manure application rates (135,67 and 22 MT/ha) did not cause significant
differences in surface flow volume. However, when surface flow volumes are compared
by incorporation depth, the troughs having surface applications (0 depth of incorporation)
indicate significantly lower surface runoff volume for series LG3. This surface runoff
volume is less than 40% of the flow volume observed for the other incorporation depths.
For series LG3, incorporation depths of 15,10 and 3 cm did not result in significantly
different surface flow volumes.
Precipitation to Initiate Runoff
Precipitation to initiate runoff (PER.) is the quantity of rainfall measured from the
beginning of the precipitation event until the first surface flow is collected. Generally, the
manure treatments caused PIR to increase relative to untreated trough levels (Figures 3.3
and 3.4) for series LG2-LG4. Series LG3 (dry) indicated increased PIR relative to the
control trough with the surface applied case (0 depth of incorporation) showing the largest
increase. For the surface applied case, mean PIR (series LG3) was over four times the
control value. Analysis of variance of PIR for the three application rates and four depths of
incorporation indicated that incorporation depth explained ajxmt 70% of the PIR variation
for series LG3 while application rate accounted for less than 10% of the variation.
21
-------
2
=
uT
o
o
oc
20-i
Ig1 (untreated) Ig2(initia!) Ig3(dry) Ig4(wet)
series
Figure 3.1
Runoff Volume, by rate, series Ig1-lg4
co
^
a>
O
cc
10 -
Ig1 (untreated) Ig2(initial) Ig3(dry) Ig4(wet)
series
Figure 3.2
Runoff Volume, by depth, series Ig1-lg4
nigh rate
med. rate
low rate
untreated
Ig1 (untreated) Ig2(initial) Ig3(dry)
series
Ig4(wet)
Ig1 (untreated) Ig2(initial) Ig3(dry)
series
Ig4(wet)
Figure 3.3
Precipitation to Initiate Runoff, by rate, Ig1-lg4
Figure 3.4
Precipitation to Initiate Runoff, by depth, Ig1-lg4
22
-------
TP. TSP Concentration in Surface Runoff
Manure applications to the soil surface resulted in relatively high TP and TSP
concentrations in surface runoff when precipitation immediately followed manure
application. Concentrations were as high as 23 mg/L and 8.5 mg/L of TP and TSP,
respectively, for individual troughs. These concentrations were 19 times the TP value of
the untreated trough and 65 times the untreated TSP level. The associated TP load for this
event was 375 mg.
TP concentrations in surface runoff (Figures 3.5 and 3.6) were higher than the
control case for all manu."f application rates and depths of incorporation when precipitation
immediately followed manure application (series LG2). After drying of the soil-manure
mixture (series LG3), the TP concentration in surface runoff for all rate and depth cases
approached untreated levels.
Similar to the TP concentration trends, TSP concentration for all rates of application
and incorporation depths were greater than untreated levels for series LG2 (Figures 3.7 and
3.8). Subsequent precipitation events (LG3 and LG4) indicate that TSP concentration in
surface runoff approaches untreated levels for the treated silt loam soil used in this
laboratory series.
There was no significant difference in TP concentration among application rates.
TP concentration in surface runoff by depth of incorporation was significantly higher for
series LG2 compared with the untreated (LG1) and subsequent precipitation events LG3
and LG4. In addition, the surface application case (0 depth of incorporation) resulted in a
significantly higher TP concentration during the LG2 series compared with the three other
depths of incorporation.
The influence of incorporation depth is even more evident on TSP concentration in
surface runoff. While the application rate did not result in significantly different TSP
concentrations, the surface applied case resulted in a TSP concentration over eight times the
value recorded for the 3,10 and 15 cm incorporation depths during LG2. TSP
concentration in surface runoff for all incorporated depths was also significantly higher for
series LG2 than series LG3 and LG4.
Much of the variability of TP and TSP concentration in surface runoff can be
explained by incorporation depth. Analysis of variance indicated that incorporation depth
explained about 80% of the TSP concentration for the first precipitation event following
manure incorporation. Generally, incorporation depth explained considerably more of both
the TP and the TSP variation than application rate.
TP. TSP Load
The total load of TP and TSP in surface runoff reflect both changes in runoff
volume and TP, TSP concentrations as a result of the manure treatments (Figures 3.9-
3.12). TP load as a function of both application rate (Figure 3.9) and depth of
incorporation (Figure 3.10) indicate high losses in surface runoff when precipitation
immediately follows manure application (series LG2). Subsequent precipitation events
(series LG3 and LG4) indicate that TP load values decrease appreciably after the first
precipitation event.
23
-------
20 T
12-
Figure 3.5
TP Concentration, by rate, series Ig1-lg4
Ig1 (untreated) Ig2(init) Ig3(dry) Ig4(wet)
series
Figure 3.6
TP Concentration, by depth, series Ig1-lg4
10-1
8-
6 -
15cm.
10cm.
03cm.
Ocm.
untreated
mrtM-\
Ig1 (untreated) Ig2(initial) Ig3(dry)
series
Ig4(wet)
Figure 3.7
TSP Concentration, by rate, Ig1-lg4
Ig1 (untreated) Ig2(initial) IgS(dry) Ig4(wet)
series
Figure 3.8
TSP Concentration, by depth, Ig1-lg4
24
-------
200-n
O>
O
giooH
300-
high (4944*)
0 medium (2472*)
M low (824*)
E3 untreated
*mg tp added from treatments
200-
o>
5"
<
o
100-
Ig1 (untreated) Ig2(initial) IgS(dry) Ig4(wet)
series
Figure 3.9
TP Load(mg), by rate, Ig1-lg4
15cm
10cm
03cm
Ocm
untreated
60 n
50-
40-
"3
£_
5"
o so H
a.
v>
20-
10-
high
medium
low
untreated
Ig1 (untreated) Ig2(initial) Ig3(dry)
series
Ig4(wet)
Figure 3.11
TSP Load(mg), by rate, Ig1-lg4
Ig1 (untreated) Ig2(initial) Ig3(dry) Ig4(wet)
series
Figure 3.10
TP Load(mg), by depth, Ig1-lg4
50 -i
40-
I!30"
o
o
v>
20-
15cm
10cm
03cm
Ocm
untreated
Ig1 (untreated) Ig2(initail) Ig3(dry) Ig4(wet)
series
Figure 3.12
TSP Load(mg), by depth, Ig1-lg4
25
-------
TSP load in surface runoff is relatively high when precipitation immediately follows
manure application. For the extreme case, the TSP load in runoff for all surface
applications in series LG2 is 101 mg, or more than 31 times the untreated value. As with
TP load, TSP load in surface runoff approaches the untreated case after three precipitation
events.
Application rate was not associated with a significant difference in TP load.
However, surface application of manure did result in a significantly higher TP load in
surface runoff for series LG2. After the soil-manure mixture dried, the TP load from the
surface-applied troughs was significantly lower than the 15 cm incorporation depth as well
as the 3 and 10 cm depth.
TSP loads in surface runoff from the surface application for series LG2 and LG4
were significantly higher than other depths of incorporation.
Analysis of variance of the TP and TSP load indicated that incorporation depth
accounted for 66% and 75% of the variation in TP and TSP load, respectively, for the three
precipitation events following manure application (LG2-LG4). As with flow volume and
TP, TSP concentration, incorporation depth explained appreciably more of the variance
than application rate for the TP, TSP load results.
FIELD SERIES FB1-FB2
The purpose of field series FB1-FB2 was to compare laboratory results with field
data for the same application rates and incorporation depth treatments used in series LG1-
LG4. In addition, five control plots were added to the experimental design to more
accurately compare flow volume, concentration and loading results from the manure
amended silt loam to the untreated case.
Series FB1-FB2 involved two precipitation events on each plot. The timing of
manure applications and precipitation events provided an opportunity for characterizing the
initial high loading period in the field. In series LB1-LB6 and LBD1-LBD4 (discussed
later), which complement series FB1-FB2, load changes were observed over a longer
period of time and under various drying conditions for the same soil.
Flow Volume
When the twelve rate-depth treatments were applied in the field, the volume of
surface flow (Figures 3.13-3.14) increased significantly above control levels. As with
series LG1-LG4 the highest individual runoff volume occurred with the 135 MT/ha
application rate to the surface (0 depth of incorporation). The runoff volumes for the plots
where surface application occurred were more than five times the surface runoff volumes
observed for the control plots during series FBI.
Series FB2 followed FB1 by 24 hours. All runoff volumes from treated plots were
significantly greater than the control plots. Typically, runoff volume increased by 20-30%
over series FBI (Figures 3.13-3.14).
26
-------
100 -i
100-1
80-
1 60-
K
Figure 3.13
Runoff Volume, by rate, fb1-fb2
series
Figure 3.14
Runoff Volume, by depth, fb1-fb2
12 -\
20-1
series
Figure 3.15
TP Concentration, by rate, fb1-fb2
E 10-
fb2
series
Figure 3.16
TP Concentration, by depth, fb1-fb2
27
-------
There was no significant difference in surface runoff volume due to rate of
application. However, manure incorporation did result in significant differences in flow
volume with respect to depth and time. As indicated, incorporation depths of 0 cm and 3
cm resulted in significantly higher runoff volumes than the 10 cm and 20 cm depths for
series FB1. These differences between rates were not observed for series FB2. When
flow volumes are compared over a 24-hour period, runoff from the 10 cm and 20 cm
incorporation depths increase significantly while the 3 cm and 0 cm plots changed very
little.
TP. TSP Concentration Surface Runoff
With the exception of the low application rate (22 MT/ha), the concentration of TP
in surface runoff (Figures 3.15 and 3.16) was significantly higher than control levels in
series FBI and FB2. TP concentration was typically an order of magnitude higher than the
controls. The extreme case of surface application (0 depth of incorporation) at 135 MT/ha
resulted in a TP concentration over 30 times control levels.
TP concentration in surface runoff exhibited significant differences by depth of
incorporation for series FBI and FB2. In each case, surface application (0 depth of
incorporation) resulted in significantly higher TP concentrations than the 3 cm, 10 cm and
20 cm depths. Similarly, the 3 cm depth for series FBI and the 3 cm and 10 cm depths for
series FB2 resulted in TP concentrations in surface runoff which were greater than the TP
concentration associated with the 20 cm incorporation depths.
For series FBI and FB2, TSP concentrations in surface runoff (Figures 3.17-3.18)
were significantly greater than control concentrations for all rates of application and the 0
cm and 3 cm incorporation depths. Incorporation depths of 10 cm and 20 cm resulted in
TSP concentrations which were not significantly different from control levels. For the
cases of 0 cm and 3 cm incorporation depths, 4.4 mg/L and 1.6 mg/L TSP were observed
for series FB 1 against a mean control level of 0.14 mg/L TSP in surface runoff. As with
TP concentration in surface runoff, TSP concentration from the 0 cm incorporation depth
was significantly greater than concentrations from the other depths for series FB 1 and FB2.
Similarly, the TSP concentration in surface runoff for the 3 cm depth case was significantly
greater than the 20 cm and 10 cm depths for series FBI.
TP. TSP Load in Surface Runoff
The cumulative effect of changes in surface flow volume and concentration can be
expressed as a mass load. Figures 3.19 and 3.20 depict mass TP and TSP loads by
application rate and depth of incorporation, respectively. The load associated with the high
application rate is 995 mg TP (Figure 3.19) which is 142 times the control level. Similarly,
the surface application of manure resulted in a loss of 1926 mg TP (Figure 3.20). TSP
load (Figures 3.21 and 3.22) in surface runoff followed trends similar to TP with relatively
high losses occurring for surface applications (0 depth of incorporation).
Flow volume measurements taken the following spring indicated that the manure-
treated plots yielded relatively less runoff than the control plots. The influence of surface
applications was less after 300 days than during the FB1-FB2 series. The greatest
decreases in runoff were associated with the 3 cm incorporation depth while flow volumes
from the 20 cm depth plots were only 15% less than the volumes measured during the
FB1-FB2 series.
28
-------
o
tn
series
Figure 3.17
fSP Concentration, by rate, fb1-fb2
Figure 3.18
TSP Concentration, by depth, fb1-fb2
1000n
800-
|>600-
S"
o
400-
200-
high (35884*)
medium (17942*)
low (5981*)
untreated
*mg tp added
2000 -
J!
g 1000-
_J
o.
0 -
I
_M|
i
20 cm.
E3 10cm.
H 3cm.
El Ocm.
D untreated
^1
-^ . mzm
\
Figure 3.19
TP Load(mg), by rate, fb1-fb2
fb1 fb2
series
Figure 3.20
TP Load(mg), by depth, fb1-fb2
29
-------
300-1
200 -
o>
S"
Q.
cn
100-
fb2
series
Figure 3.21
TSP Load(mg), by rate, fb1-fb2
400-i
300-
D>
5"
<
O
200-
100-
20cm.
10cm.
3cm.
Ocm.
untreated
series
Figure 3.22
TSP Load(mg), by depth, fb1-fb2
30
-------
Changes in TP concentration over time were greatest for the case of surface
applications after 300 days; TP concentration was significantly less than that observed
during series FB1 and FB2. Conversely, TP concentration in surface runoff was higher
for the 20 cm incorporation depth after 300 days than observed for series FBI and FB2.
TSP concentration decreased significantly in surface runoff for the case of surface
application. This trend was also observed for the 3 cm depth. Although differences over
time for the 10 cm depth were not significant, an increase in TSP concentration in surface
runoff was observed for the 20 cm incorporation depth after 300 days.
TP loads were decreased during the spring runs with losses after 300 days totaling
less than 125 mg (9.2 kg/ha) for all application rates and depths of incorporation.
Generally, TSP load after 300 days was only 5-10% of FBI and FB2 series levels.
Control losses were significantly less than losses for all application rates and incorporation
depths.
LABORATORY SERIES LB1-LB6
Flow Volume
The air-dried soil (7.1% moisture) yielded little runoff (Figure 3.23) during series
LB1 (no treatment). As with series LG2 and FBI, surface runoff volume increased for
high manure application rates. For series LB2, the troughs treated with 135 Mt/ha of
manure exhibited a runoff volume 24% higher than untreated levels. After two and ten
days, (respectively series LB3 and LB4, Figure 3.23), troughs treated with a high
application rate did not yield a significantly higher surface runoff volume than untreated
levels. The following two precipitation events (series LB5 and LB6) produced lower
surface runoff volumes for the high-rate troughs. In series LB5 (t=25 days), high
application surface runoff volume was only 49% of the untreated volume. Although
surface runoff from the high-rate troughs was less than the untreated level after 62 days
(series LB6), the difference was smaller than that observed for the 25-day event.
When surface flow volume is categorized by incorporation depth, series LB2 (t=0)
and series LB5 (t=25 days) indicate different effects of manure amendments to the soil
(Figure 3.24). For series LB2, runoff volume was 10-20% higher than the untreated case.
Conversely, for series LB5 manure-treated soil resulted in surface flow volumes 40-60%
less than the untreated troughs.
Precipitation to Initiate Runoff (PIR)
The initial wetting of the air-dried soil (series LB1) resulted in PIR values which
were relatively high (Figure 3.25). Conversely, precipitation event LB2 immediately after
manure application resulted in PER values which were 5-10% of LB1 (the untreated series).
Subsequent series LB3-LB6 indicated that PIR generally increased with each series relative
to the values recorded during series LB2. After 62 days (series LB6), PIR values were
more than three times those of series LB2.
TP and TSP Concentrations in Surface Runoff
Similar to other series runs, LB2 and FBI, surface runoff collected immediately
after the application of manure contained a relatively high TP concentration compared to the
untreated case. Approximately an order of magnitude increase in TP concentration was
observed at t=0d. After two days (series LB3), the concentration of TP in surface runoff
31
-------
O
o
z
LB1 (untreated) LB2(t=0)
LB3(t*2) LB4(t=10)
series
Figure 3.23
Runoff Volume, by rate, Ib1-lb6
LB5(t=25) LB6(t=62)
o>
4>
£
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10) Ib5(t=25)
series
Figure 3.24
Runoff Volume, by depth, Ib1-lb6
Ib6(t=62)
32
-------
12-
o
OL
high
moderate
low
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10) Ib5(t=25)
series
Figure 3.25
Precipitation to Initiate Runoff, series IbMbS
Ib6(t=62)
o
60-
50-
high (4944*)
E2 low (824*)
H! untreated
*mg tp added
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10)
series
Figure 3.26
TP Load, by rate, series Ib1-lb6
Ib5(t=25) Ib6(t=62)
33
-------
was approximately two to three times the control level. The following three precipitation
events indicated that TP concentration was not significantly different than untreated levels.
Thus after three precipitation events the impact of manure amendments to the soil was
relatively small.
When TP concentration in surface runoff is examined by depth of incorporation
treatments, results vary appreciably. In particular, surface applications (0 depth of
incorporation) result in TP concentrations almost 40 times higher than untreated levels
when precipitation immediately follows surface application. This difference is considerably
less after two days with TP concentration in surface runoff approximately five times control
levels for series LB3. Similarly an incorporation depth of 3 cm produced significantly
higher TP concentrations for series LB2 and LB3.
Incorporation depths of 10 cm and 15 cm resulted in TP concentrations which were
similar to untreated levels for all series runs. In addition, after 10 days (series LB4)
surface application and the 3 cm incorporation depth indicated that TP concentration in
surface runoff approached untreated levels.
The effect of the rate and depth manure treatments on TSP concentration was
apparent during series LB2 and LB3, the two precipitation events immediately following
manure application. High concentrations of TSP in surface runoff were observed during
series LB2 with almost a 30-fold increase above control values. An incorporation depth of
3 cm resulted in TSP concentration significantly less than those observed in surface
applications yet still over eight times higher than the untreated values.
As with TP concentration in surface runoff, incorporation depths of 10 and 15 cm
resulted in TSP levels which were comparable to untreated values for all series runs. In
addition, after four precipitation events TSP concentration associated with 0 and 3 cm
incorporation depths were not significantly different than the untreated soil.
TP and TSP Load
The combined effect of flow volume and TP, TSP concentration result in loadings
which vary widely over time both with respect to application rate and depth of
incorporation (Figures 3.26-3.29).
The application of manure to the soil resulted in a mass load in surface runoff as
high as 391 mg TP for the surface applied case (t=0d). This load was almost 50 times the
untreated load and if the simulated precipitation event were extrapolated to an annual
quantity of 100 cm, would be equivalent to an annual TP load of 183 kg/ha. After two
days (series LB3), the TP load in surface runoff from surface applied case was about six
times the untreated level.
Although differences between manure treatments and the untreated soils were less
for series LB4 (t=10d) it was series LB5 which, similar to series LG3, exhibited decreased
loading in surface runoff for treated soils. This effect was observed for both TP and TSP
loads for all application rates and depths of incorporation (Figures 3.26-3.29).
TSP mass load in surface runoff followed similar trends to TP load. For surface
applications and precipitation events immediately following manure application, TSP load
34
-------
200 -i
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10)
series
Ib5(t=25) Ib6(t=62)
Figure 3.27
TP Load (mg), by depth, series Ib1-lb6
60 -
50 -
20-
10-
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10)
series
Figure 3.28
TSP Load, by rate, series Ib1-lb6
Ib5(t=25) Ib6(t=62)
35
-------
was as high as 35 times untreated levels. After 10 days (series LB4) there was no
sienificant difference in TSP load in surface runoff between manure treated soils and the
untreated soils (Figures 3.28 and 3.29).
LABORATORY SERIES LBD1-LBD4
The laboratory troughs used for series LG1-LG4 and LB1-LB6 were covered
between precipitation events. The effect of this cover was to reduce surface evaporation,
slow the drying process and minimize cracking of the soil manure mixture. Following
analysis of all LG, LB and FB series runs, the importance of the first few wet-dry cycles
was evident.
The results of series LBD1-LBD4 confirm the importance of the initial drying cycle
when manure is applied to the surface. Figure 3.30 indicates changes in runoff volume for
drying times (time between simulation runs) of two, five, and ten days. After two days,
mean flow volume associated with rainfall simulation events decreased to approximately
53% of the flow volumes observed for precipitation events which immediately followed
manure application (runs LG2, LB2). Flow volumes observed after five and 10-day
drying periods are also greatly reduced with the volume of the 10-day runs less than 20%
of the initial high values reported for series runs LG2 and LB2.
NORMALIZED TP, TSP LOADS IN SURFACE RUNOFF
Series LG1-LG4
When TP load is normalized by application rate, TP loads for the high and medium
application rates are less than 40% of the normalized low rate values (Figure 3.31). As
indicated in Figure 3.32, the high normalized load in surface runoff associated with surface
applications is greatly reduced at the 3 cm incorporation depth in the LG2 series.
Normalized TSP loads indicate high values for the low application rate troughs
(Figure 3.33). Increases of as much as six times the high and medium rate values were
observed for normalized low rate TP loads in surface runoff. Untreated values are included
for reference in Figure 3.33. Incorporation depths of 3,10 and 15 cm resulted in
normalized TSP loads in surface runoff which were less than 40% of the mass TSP load
associated with surface applications for series LG2 (t=0). Generally the 3 cm incorporation
depth was significantly lower than surface application TSP losses, yet higher than
normalized TSP losses observed for the 15 and 10 cm incorporation depths (Figure 3.34).
Series LB1-LB6
The relatively high normalized TP load observed in series LG1-LG4 was also
evident in laboratory series LB1-LB6 (Figure 3.35). For series LB2 (t=0), normalized TP
load rate for the low application was over six times the load observed for the high
application rate (135 MT/ha). For subsequent precipitation events LB3-LB6, normalized
TP load in surface runoff was also greater for the low application rate 22 MT/ha.
However, the increase in normalized TP load for the low application rate compared with the
high application rate varied greatly between series. For series LB4 (t=10d), for example,
normalized TP load for the low rate was only 1.8 times the value recorded for the high rate
while the low rate was 19 times the .high rate for series LB6 (t=62 days).
36
-------
TOO -
80-
_ 60-
S
Q.
" 40-
20-
n .
arnTl n fin
1
1
-i ^Bii
I
15cm
@ 10cm
EJH 3 cm
0 Ocm
[H untreated
-1 _^8^-, _
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10)
series
Figure 3.29
TSP Load, by depth, series Ib1-lb6
Ib5(t=25) Ib6(t=62)
20 -,
inital wetting
Time(days)
Figure 3.30
Flow Volume for Different Drying Times, Ibd1-lbd4
37
-------
200 -I
10cm
3cm
Ocm
CU untreated
Ig1 (untreated) Ig2(initial) IgS(dry) Ig4(wet)
series
Figure 3.31
Normalized TP Load(mg/kg), by rate, Ig1-!g4
Ig1 (untreated) Ig2(initial) IgS(dry)
series
Ig4(wet)
Figure 3.32
Normalized TP Load(mg/kg), by depth, Ig1-lg4
40 n
40-1
Igl(untreated) Ig2(initial) Ig3(dry) Ig4(wet)
series
Figure 3.33
Normalized TSP Load(mg/kg), by rate, Ig1-lg4
Ig1 (untreated) Ig2(initial) Ig3(dry)
series
Ig4(wet)
Figure 3.34
Normalized TSP Load (mg/kg), by depth, Ig1-lg4
38
-------
200 i
Ib1 (untreated) Ib2(t=0)
80-
£
sr
Ib3(t=2) Ib4(t=10)
series
Ib5(t=25) Ib6(t=62)
Figure 3.35
Normalized TP Load(mg/kg), by rate, Ib1-!b6
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t=10)
series
Ib5(t=25) Ib6(t=62)
Figure 3.36
Normalized TP Load(mg/kg), by depth, !b1-lb6
39
-------
For series LB1-LB6, normalized TP load by incorporation depth emphasizes the
effect of incorporation within the top 3 cm of soil (Figure 3.36). It is evident from Figure
3.36 that mass loading of TP per unit manure input is much less for incorporated manure
than the normalized TP load associated with surface application. In addition, differences in
normalized load lessened considerably after precipitation event LB3. However, as with
variations in normalized TP load by incorporation depth, differences between normalized
loads for precipitation events LB3-LB6 vary considerably.
Normalized TSP load in surface runoff (Figure 3.37) indicates high loading per unit
of manure applied for the low application rate (22 Mt/ha equivalent). For LB2, the low
application rate would yield 152 mg of TSP for each kg of manure applied to the laboratory
trough while the high rate yields 18.4 mg/kg of manure applied. This high rate TSP yield
is 12% of the low normalized yield. Subsequent precipitation events LB3-LB6 resulted in
low rate normalized TSP yields which were 3.8 to 8.2 times the high rate values.
When normalized TSP load in surface runoff is presented by depth of incorporation
(Figure 3.38) most values are comparable to the TSP mass load observed for the control
troughs. Exceptions to this observation are the mass loads associated with surface
applications for precipitation events LB2 and LB3 which were 36 and 14 times the control
values, respectively. In addition, normalized TSP load in surface runoff for the 3 cm
incorporation depth was four times the control TSP mass load for LB2.
PARAMETER CORRELATIONS
The correlation coefficient between two parameters can help explain variability
between observations and aid in the understanding of physical/chemical processes.
However, it is important to note that statistical inference does not allow a direct cause-effect
statement.
Comparisons between different correlation coefficients were made by grouping
series runs according to the time period between manure application and runoff. This
grouping was made to attempt comparisons at stages of manure degradation which were
roughly similar between series. The various groups are listed below:
Group 1. Control Runs - parameter correlations derived from water samples from
untreated plots (LG1, LB1, FB1-FB2)
Group 2. Initial Runs - parameter correlations derived from water samples collected
within two days of manure application to the soil (LG2, LB2, LB3, FBI, FB2)
Group 3. Intermediate Runs - parameter correlations derived from water samples collected
between three and thirty days after manure application to the soil (LB4, UB5)
Group 4. Long-term Runs - parameter correlations derived from water samples collected
between 31 and 90 days of manure application to the soil (LG3, LG4, LB6)
Group 1. (control runs) statistical analysis indicated that TP concentration and
suspended solids (SS) had a correlation coefficient of 0.71, while TSP concentration and
pH had a coefficient value of 0.79. Similar degrees of correlation were observed for
40
-------
D>
<
O>
_§,
a
<
o
a.
V)
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(t-10) Ib5(t=25)
series
Ib6(t=62)
Figure 3.37
Normalized TSP Load(mg/kg), by rate, Ib1-lb6
CD
E
50-1
40 -
30-
20-
10 -
Ib1 (untreated) Ib2(t=0)
Ib3(t=2) Ib4(ttl0)
series
Ib5(t=25) Ib6(t=62)
Figure 3.38
Normalized TSP Load(mg/kg), by depth, Ib1-lb6
41
-------
Group 2 (initial runs) with the correlation between IP concentration and SS, TSP
concentration and pH equal to 0.73 and 0.81, respectively. In addition, Group 2 displayed
a high correlation between TP and TKN concentration. The correlation between flow
volume and TP, TSP, pH and SS concentration varied between 0.60-0.73. A correlation
between flow volume and other parameters was not observed to be greater than 0.50 for the
other three Groups. Group 3 correlations again indicated coefficients greater than 0.50 for
TP and SS. In addition, the correlation coefficient for TSP and TKN concentration was
0.69 for series runs which took place 2-30 days after manure application. Finally, Group 4
runs indicated correlation coefficients of 0.78 and 0.72, respectively, for TP-SS and TP-
TKN. Although not as high as other groups the correlation between pH and TSP was still
greater than 0.50 for these longer term series runs.
VARIATIONS IN NUTRIENT CONCENTRATION IN SURFACE RUNOFF
WITHIN EVENTS
For many series runs, individual parameter concentration changed in similar
patterns. This is important when the results of simulated precipitation events are
extrapolated to storms of either a lower or higher intensity.
An example of variations in TP concentration within series FB1-FB2 are given in
Figure 3.39. The first sample taken yielded a relatively low TP value while the second
sample indicated the highest series value. Subsequent samples over the 24-hour run period
were less than 35% of the maximum TP concentration. TP concentration changes for
series LB1-LB3 similarly indicate relatively high or peak concentration observed early in
the run with later samples indicating a considerably lower TP concentration over a 48-hour
period (Figure 3.40).
Although at lower concentrations, TSP in surface runoff (Figure 3.41) followed a
- similar pattern to TP with a maximum concentration of 2.5 mg/L indicated for the second
sample of series FB1 (immediately following manure application). The dilution effect for
samples collected over a short time period (Figure 3.42) was observed for series LB1-LB3
with a maximum TSP concentration in surface runoff occurring for the first sample
collected in series LB2, 3.6 mg/L.
Considering the high correlation between TP and SS it is not surprising that the
suspended solids concentration in surface runoff follows a similar trend to TP (Figure
3.43). Thus, over a 24-hour period and two precipitation events (series FB1-FB2), SS
peaked at almost 6000 mg/L while the last sample of series FB2 indicated about 1000 mg/L
in surface runoff.
SURFACE RESIDUE SERIES (LRB1 - LRB6)
As Wishmeier (1979) points out, even small quantities of straw mulch increase
infiltration and decrease soil erosion. The effect of surface applied manure is consistent
with two particularly important aspects of mulch systems which decrease TP, TSP loading;
After the surface manure pack has dried a residue cover is evident. This
residue can result in almost complete surface cover when high rates of
woodchip, sawdust or straw bedding have been used.
42
-------
20 n
o 10-
o
o
20
-a TPConc
24 hrs.
40
60
80
Time(minutes)
Figure 3.39
TP Concentration, by sequence, aeries fbt-fb2
series fb2
100
= 10-
D>
B
O
o
aeries Ib1
20
48 hrs
-a TP Conc(mg/l)
48 hrs
series Ib3
40 60
Time(minutes)
80
100
Figure 3.40
TP Concentration, by sequence, series Ib1-lb3
43
-------
3n
6
o
o
1 -
o
3-
2-
1 -
o TSP Cone.
series fb1
24 hrs.
series fb2
20
40 60
Time(mlnutes)
Figure 3.41
TSP Conc.(mg/l), by sequence, series fb1-fb2
80
100
series Ib2
48 hrs
TSP(mg/l)
48 hrs
series Ib3
20 40 60 80
Time(minutes)
Figure 3.42
TSP Concentration, by sequence, series Ib1-lb3
100
44
-------
6000 n
5000-
4000-
£ 3000 -
2000-
1000 -
o>
»
co
series fb1
SS(mg/l)
24 hrs
.series fb2
20
40
60
Tlme(minutes)
80
Figure 3.43
SS Concentration, by sequence, series fb1-fb2
100
200-
tsp load
* manure application
2 7 11
Time(days)
Figure 3.44
Loading Parameter, by Time, residue series
20
45
-------
20 T
D
H IP
10
20
Time(days)
Figure 3.45
TP(mg/l), by Time, residue series
Figure 3.46
Loading Parameters vs. Cover.all
30
46
-------
80 -i
tn
DC
LU
DC
a.
(JJ
60-
40-
20-
I
runoff(l)
0 TP
H TSP
0 tpload
CD tsp load
1
0.41
manure rate(kg)
Figure 3.47
TP Loading Parameters vs. Rate
I
2.48
1 2
Application rate (kg)
Figure 3.48
TSP(mg/l) vs. Application Rate
47
-------
The resulting mulch effect from manure applications to the surface will
improve hydrologic properties of the soil and decrease winter frost depths
(Benoit 1984, 1985).
Differences in the volume of runoff for the residue series runs (Figure 3.44) are
small and showed no trend with time. TP load with a residue cover was reduced by 60%
from the untreated case. When manure was applied to the residue, TP and TSP
concentration increased significantly. However, the increase in TP and TSP load
associated with the higher concentrations were not as great as those observed when manure
was applied to the surface of bare soil (series LG1-LG4 and FG1-FG3). On the other
hand, the fraction of TP which is soluble was high (60-90%) both when manure
applications were made to the surface and over residue.
Figure 3.45 shows the effect of manure applications on TP concentration over time
with a concentration spike occurring at 11 days, corresponding to the time when manure
was applied over the surface residue. When all series data are pooled (Figure 3.46) TSP
load and TP load increase appreciably with residue cover This load increase is likely due to
the fact that manure applied over the residue cover is more easily detached and transported
in overland flow. The effect of manure application rate (Figure 3.47) also indicates
increased TSP load and comparable or decreased TP load with increased application rate.
Changes in TSP concentration and load are particularly important because virtually
all of this load is readily available for algae growth. Figures 3.48 and 3.49 indicate that
both manure application rate and residue cover increase TSP concentration in runoff. The
higher concentrations associated with surface manure applications validate earlier Phase I
laboratory and field experiments. However, the clear association of TSP concentration
with com residue rate suggests that the availability of phosphorus is controlled by water
movement and that the decreased loads observed when surface manure applications are
dried (series LG-LG4, FB1-FB3 and LB1-LB6) are less evident with soil mulch systems.
The quantity of water retained after surface manure treatments is reflected in Figures
3.50 and 3.51. Figure 3.50 indicates the change in moisture after sequential wet-dry
cycles. The higher moisture content results in smaller amounts of moisture retained (Figure
3.51) by the soil manure mixtures. As indicated in Figure 3.51 after simulated precipitation
at 10 and 20 days the quantity of water retained decreased although the percent soil
moisture was relatively high in most cases. This phenomena, in part, explains the high
losses of soluble phosphorus since drying and sorption processes are decreased with the
wet soil surface conditions under the mulch cover. On the other hand the apparent surface
sealing which occurred during precipitation immediately following manure application
(series LG1-LG4, FB1-FB3, LB1-LB6) does not appear to inhibit surface infiltration. This
later effect is reflected in lower observed runoff and high subsurface flow volumes.
When residue series TP and TSP loads are normalized for manure application rate
(Figure 3.52) the higher rates result in lower unit losses. These observations confirm
Phase I findings for manure applied to a bare soil.
48
-------
1
o
50 -i
40
30-
20-
100
cover rate(g)
Figure 3.49
TSP(mg/l) vs. Residue Cover
D
150
10-
Q % moisture
2 3
w-d cycles
i
5
Figure 3.50
Mean Moisture Retention for Wet-Dry Cycles
49
-------
DC
111
8-1
6-
o
I «
DC
2-
5 10
Rate-Depth Treatments
15
Figure 3.51
Water Retention, series, LBD
400 n
normtp
normtsp
.41
manure rate (kg)
2.48
Figure 3.52
Normalized TP, TSP Loads, residue series
50
-------
SUMMER FARM RUNS
Although in the short-term (two to six months) specific field operations and conditions
were known, the history of any field (particularly with respect to manure application rates) was
unknown. Therefore a high degree of interaction between residue, application rate, soil type,
and crop will buffer and obscure trends observed in more controlled experiments (series LG1-
LG4, FB1-FB3, LB1-LB6, LBR1-LBR6). This is particularly evident when all data are pooled
to observe TP, TSP concentration and loading for different manure application rates (Figure
3.53). Perhaps the only clear trend is indicated by the increased TSP load where manure
applications have occurred. The general lack of cause-effect relationships can be related to three
primary factors:
where manure applications have occurred in previous years the rate of
application has varied greatly
the quantity and quality of residue associated with surface manure
application vary greatly
in performing field evaluations, relatively large differences in data are
possible due to spatial variability
The mechanism by which manure treated soils infiltrate water and initiate runoff can
be observed in Figure 3.54. Although time to ponding increased with application rate the
total time to initiate runoff from simulated precipitation did not indicate a consistent trend.
Again, the three factors listed above would typically cause a cumulative convergence of
observations despite short-term treatments.
Simulated precipitation from farm series runs indicated lower normalized TP, TSP
loads for higher application rates (Figure 3.55). Although the normalized loads for 99 and
67 mt/ha were similar, both TP and TSP losses per kg manure applied were less than the
low rate (33 mt/ha) loads.
Growing season differences in runoff volumes and TP, TSP concentration
(Figures 3.56 and 3.57) resulted in higher loads for no-till and chisel systems compared
with conventional moldboard plowing. It should be noted that this data was collected
approximately 45 days after planting. Other investigators (Mueller, 1979, Romkens, 1973)
have shown that advantages of infiltration and nutrient retention of conventional tillage are
typically short lived. In addition, the period of critical concern to this study is spring
runoff when the reverse order of loading parameters is possible.
When all data is pooled and loads are calculated by crop (Figures 3.58 and 3.59)
corn losses are significantly higher than alfalfa. It should be pointed out that all simulated
precipitation runs were made shortly after the first cutting of alfalfa which resulted in an
appreciable area of exposed soil.
Differences in concentration between soil types (Figure 3.60) indicate that the sand
and clay soils have a relatively shallow zone of interaction resulting in a significantly
reduced TSP concentration.
51
-------
CD
50 n
40 -
30-
o
1
<
o
20H
10 -
runoff(liters)
TP(mg/l)
TSP(mg/l)
TP Load(mg)
TSP Load(mg)
rate(mt/ha)
Figure 3.53
Loading Parameters, farm series
rate(mt/ha)
Figure 3.54
PIR, farm series
52
-------
NormTP
NormTSP
Figure 3.55
Normalized TP, TSP, farm series
runoff(liters)
TP(mg/I)
TSP(mg/l)
CONV
Figure 3.56
Loading Parameters vs. Tillage
53
-------
D>
TP Load(mg)
TSP Load(mg)
DC
Figure 3.57
TP, TSP Load vs. Tillage
corn
runoff(liters)
TP(mg/l)
TSP(mg/l)
crop
Figure 3.58
Loading Parameters vs. Crop
alfalfa
54
-------
TP Load(mg)
TSP Load(mg)
20 n
- 10-
LL
U.
O
corn
alfalfa
crop
Figure 3.59
TP, TSP Load vs. Crop
runoff(liters)
TP(mg/1)
TSP(mg/I)
Clay
Figure 3.60
Loading Parameters vs. Soil Type
55
-------
20 i
en
JE
O
O 10
TP Load(mg)
TSP Load(mg)
Figure 3.61
TP, TSP Load vs. Soil Type
1000-1
800 -
600-
400-
200-
SS(mg/l)
01235
residue(mt/ha)
Figure 3.62
Suspended Solids vs. Residue Level
6 -i
5-
4 -
D>
E
o. 3 -
to
2 J
1 -
y = - 0.0501 + 0.4188X R = 0.93
40-i
30 -
en
£
5"
020H
Q.
in
5 10
TP(mg/l)
Figure 3.63
TP vs. TSP Concentration, farm series
15
10-
D
TSP Load(mg)
D B '
y = - 0.0624 + 0.3216x R = 0.53
D
10 20 30 40 50 60
TP Load(mg)
Figure 3.64
TP Load vs. TSP Load, farm series
56
-------
Figure 3.61 indicates the variation in the hydrologic response of the different soil
types. Despite a relatively low concentration of TP in runoff, the total mass TP load is
greatest for the clay loam soil.
The residue rate directly influenced suspended solids (SS) concentration (Figure
3.62). However, the quality and coverage of residue indicated that relatively low cover
rates (1-3 Mt/ha) resulted in SS concentrations similar to the untreated case. The reasons
for these observations likely involve an interaction of the following factors:
Most of the soils in this study have received long-term treatments of
manure. Even where there is no residue cover, soil aggregation and surface
infiltration improvements from previous manure applications may decrease
suspended solids in runoff.
The presence of bedding and undigested fiber in certain manures will have a
positive effect on suspended solids concentration utilizing the same
mechanisms as surface residues.
As indicated in Phase I studies, the correlation between TP and TSP concentration
and load on manure treated soils is relatively high. This trend (Figures 3.63 and 3.64) was
verified for growing season samples collected on the Wayne and Oswego County farms.
SURFACE CONDITIONS AND THEIR EFFECT ON TP, TSP LOADING
Drying Mechanisms
Sobel (1971) describes three basic mechanisms (mechanical, absorption, and
thermal) for moisture removal from manure. These processes all can be accomplished as
intensive treatment measures. The two mechanisms which naturally occur in manure
disposal systems which can be modified to achieve reduced TP, TSP loading are
absorption and drying.
As indicated in Figure 3.65, the moisture absorbing capacity of common bedding
materials can be quite high. The use of bedding particularly during periods of high delivery
is one practical TP, TSP control measure.
Short-term drying of manure (Figure 3.66) emphasizes the importance of wind
effects and thickness of the manure pack. Although the deeper pack (Figure 3.67) indicates
an appreciably longer drying time requirement, initial drying rates are high with moisture
content dropping to 50% in about three days. The shrinking which would occur in this
case would cause appreciable increases in infiltration as demonstrated in all LED series
runs.
Series LED
An indirect method of observing changes in moisture characteristics of manure
treated soils is to note changes in moisture content with wetting and drying cycles. As
indicated in Figure 3.68 a pattern appears which indicates a decrease in moisture content
associated with the initial drying of the surface applied manure. Once this cycle has
occurred manure amendments cause increased absorbance and higher moisture content as
expected. As the manure soil mixture undergoes wetting and drying cycles the precipitation
to initiate runoff tends to increase as indicated in Figure 3.69.
57
-------
% MOISTURE
ABSORBANCE(kg/kg)
Ln
00
c
5
o
<
o
01
o
o
to'
cr
3 VI
o
-------
.32 cm, vent.
.63 cm.vent.
.32 cm.static
.63 cm.static
2.13cm,lbdseri
100
200 300
Time(hrs)
400
500
Figure 3.67
Manure Drying Curves
Trough 1
Trough 4
Trough 7
Trough 10
Trough 12
Trough 13
Time(days)
Figure 3.68
Trough Moisture Content(%)
10
59
-------
40 -i
30 -
± 20 H
10 -
LBD1(2days)
LBD2(5 days)
* LBD3(10days)
o LBD4(20days)
i
30
i
10
Time(days)
Figure 3.69
PIR, Series LBD
r~
20
norm TP
norm TSP
30 60
rate (mt/ha)
100
Figure 3.70
Normalized Load, by rate, farm series
60
-------
<
0) 10
-- O)
3 o
00
o
o -
PH
oo
i
<£>
NORMALIZED TP, TSP(h/kg)
-» ro
I D
Q Q
to
ro
en
p
o
IV)
x
i\>
01
-------
Farm Series
When manure was applied at rates of 10-100 Mt/ha both normalized TP and TSP
load decreased with increasing application rate (Figure 3.70). Although the TP normalized
load indicated relatively constant values above 30 Mt/ha, TSP load indicated decreasing
normalized loads after four drying days. This downward trend, although subtle, is
indicated in Figure 3.71 for all pooled data.
The effect of pH on TSP concentration and load showed a high correlation in all
series runs. This effect was also observed for farm series runs (TX1-TX20, AX1-AX28).
In addition there appeared a maximum pH effect on surface applied plots (Figure 3.72) of
approximately 7.8 at an application rate of 50 mt/ha. Decreases in pH were observed for
rates less than and greater than 50 mt/ha.
The loading of TP and TSP associated with surface applications of manure for farm
series runs (four drying days) indicate increased loading (Figure 3.73) with application rate
for both TP and TSP. However, runoff volume decreased with increasing rate. Although
the correlation coefficient indicates a weak relationship, this downward trend confirms
earlier laboratory and field observations. The quantity of precipitation to initiate runoff
(PIR) were not consistent (Figure 3.74) and probably reflected differences in manure
characteristics and soil types between farms.
The relatively high fraction of TSP to TP load was observed in all manure treated
soils in the laboratory, field and farm runs. In particular, surface applied treatments for
farm runs supports this observation (Figures 3.75 and 3.76) with a high degree of
correlation between TP and TSP concentration. Linear correlations between TP, TSP load
and manure application rates (Figure 3.77) did not yield highly significant values. This is
likely due, in part, to a high variance in runoff volume and the inherent spatial variability of
the farm series runs.
62
-------
TIME TO PONDING AND RUNOFF
ro A. o> oo
LOADING VARIABLES
TJ
3J
(O
c
IB
S.3 -=
n
O) CO
*.
o
o>
o
oo
o
°
o
o
n
en
c
3"
s
o ^
g 10
Q. C
co
o
^
»
-------
5-
4-
o TSP(mg/l)
o
(A
3-
2-
B
y = - 0.0501 + 0.4188x R = 0.93
1 -
B
10
Figure 3.75
vs. TSP Concentration, farm series
15
64
-------
100 n
80-
60-
c
<
o
a. 40-
20-
TP Load(mg)
TSP Load(mg)
20
y = 8.3554 + 0.5251 x R = 0.53
(TP)
y = 3.8557 + 0.2585X R = 0.48
(TSP)
40
60
rate(mt/ha)
80
100
120
Figure 3.76
TP, TSP Loading vs. Rate, farm series
40-
y= - 0.0624 + 0.3216X R = 0.53
30
TP Load(mg)
Figure 3.77
TP Load vs. TSP Load, farm series
65
-------
SECTION IV
DISCUSSION
Application Rate Effects
Surface flow volume was not significantly related to changes in application rate for
individual series runs. However, when all series data are analyzed on a unit area basis,
trends can be identified which may help in explaining some of the physical differences
between the short-term and long-term effects of manure applications on phosphorus losses.
Figure 4.1 indicates that the volumes of surface runoff associated with high application
rates are larger than those reflecting the low rates when precipitation follows 0-10 days
after application for the pooled series data. When the soil manure pack is allowed to dry,
surface runoff volumes associated with the high rate are less than those for the low rate
when precipitation occurs at 25-300 days after application (Figure 4.1). The drying effect
can be related to the interactions of several factors influencing the condition of the soil
surface. These factors are discussed later in this section.
When precipitation occurs within two days of manure application, TP and TSP
concentration in surface runoff from manured plots are significantly higher than control
levels for the pooled data (Figures 4.2 and 4.3). Typically, the TP concentration
approached 10 mg/L and TSP approached 3.0 mg/L for the first runoff event (t=0)
immediately following manure application. After this initial level, subsequent simulated
precipitation events (10,25,44, 59,62 and 300 days) indicated greatly reduced
concentrations converging toward control levels of 0.5-1.5 mg/L TP and 0.1-0.4 mg/L
TSP for all pooled series data.
The net effect of manure application on flow volume and phosphorus concentration
is to increase loading of TP and TSP by as much as an order of magnitude above control
plots for the first simulated precipitation event following manure application if this event
occurs within two days of application (Figures 4.4 and 4.5). After the first event, load
differences tend to be considerably less. Differences between application rates do not
indicate consistent trends for the pooled data nor do they exhibit a significant statistical
relationship with the variability in TP, TSP loading. Therefore, it would appear that the
application of manure will likely result in relatively high loading of TP, TSP for
precipitation events immediately following manure application regardless of rate. Losses
decrease appreciably with subsequent precipitation events and particularly after a drying of
the soil manure pack.
Incorporation Effects
Surface flow volume appeared to be more sensitive to incorporation depth than to
application rate (Figure 4.6) particularly for the case of surface applications. Manure
incorporation of 3 cm noticeably improved infiltration and reduced runoff in most cases.
The effect of a drying period on surface applied manure can be readily observed for runs at
25 and 44 days. Li addition, the results of series LBD1-LBD4 indicate that under favorable
drying conditions, a period of two to five days between surface application and the first
precipitation event, will result in greatly reduced flow volumes. Generally, after the initial
precipitation event, flow volume associated with surface applications varied with respect to
other manure incorporation depths according to moisture content. For example, the
relatively high value at 54 days (Figure 4.6) is associated with a relatively high moisture
content of the soil manure pack.
66
-------
80 n
70-
CM
E
o
o
z
DC
50-
40-
30-
20
D
i 1 ' 1 ' r
20 40 60
Tlme(days)
80
Figure 4.1
Mean Runoff Volume, by rate, all series
10 -
i
8
£
o
o
a
4-
B
20
40
Time(days)
60
80
Figure 4.2
Mean TP Concentration, by rate, all series
67
-------
z
o
o
Q.
CO
1 -
B
Q high rate
moderate rate
low rate
I
20
40
Time(days)
60
Figure 4.3
Mean TSP Concentration, by rate, all series
80
800
600-
§ 400 H
o
200-
20
Q
40
Time(days)
60
B
80
Figure 4.4
Mean TP Load, by rate, all series
68
-------
300 -
^ 200-
S"
o
w 100-
D
Q high rate
low rate
untreated
*
0 Q
B B B B B 8 *
B 5 B H
t = 0 t=1 t=2
t = 10 t = 25 t=44
Time(days)
Figure 4.5
TSP Load, by rate, all series
t = 54 t = 62 t=300
100 n
80 -
60
5
It 40 H
O
20-
a
i
*
0
1
20 40 60
Time(days)
Figure 4.6
Mean Runoff Volume, by depth, all series
80
69
-------
20
u
o
u
10-
H 15cm
10cm
3cm
o Ocm
untreated
i
PI
8
1
8 n
0>
O
O
O.
CO
20
i
40
60
Time(days)
Figure 4.7
Mean TP Concentration, by depth, all series
Figure 4.8
Mean TSP Concentration, by depth, all series
I
80
I
6-
4 -
g
2-
<
I
i
D
a Ocm
15cm
10cm
o 3cm
untreated
Q
rf i 1 1 S
1 !! |i>|
0 20 40 60 8
Time(days)
70
-------
2000-
CM
E
I*
s
o
1000-
4-
D
I
*
t=0 t=1 t=2 t=10 t=25 t=44
Time(days)
Figure 4.9
Mean TP Load, by depth, all series
t=54 t=62 t=300
600 n
500
,
ff 400-
0.
§ 300-
Q.
{2 200-
100 T
0^
c
o
0 15cm
10cm
o 3cm
Ocm
untreated
|l I 1
20 40 60 8
Time(days)
Figure 4.10
Mean TSP Load, by depth, all series
71
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When all series data are pooled it is evident that incorporation depth had a strong
influence on TP and TSP concentration for the first one or two events following manure
incorporation (Figures 4.7 and 4.8). Typically, TP and TSP concentrations in surface
runoff for the surface-applied treatments are one to two orders of magnitude greater than
TP, TSP concentrations associated with the untreated troughs for this initial case. With
subsequent precipitation events this pattern is greatly diminished but still somewhat
evident, particularly the TSP concentrations (Figure 4.8).
The effect of incorporation depth on phosphorus loads in surface runoff is
demonstrated in the total TSP loads for pooled data from all series in Figures 4.9 and 4.10.
All series runs, whether manure applications or stabilized soil manure mixtures indicated
decreased losses of phosphorus when manure was incorporated. It appears that any soil
disturbance following surface manure application which left soil or residue on the surface
of the manure or which mixed soil residue and manure to any extent would significantly
reduce loading of all parameters. Wet-dry cycles cause the incorporation effect to be
buffered. Finally, the shallower the incorporation depth the higher the TSP concentration
for both the initial manure case and the dry manure soil mixture.
Factors Affecting Phosphorus Loading
Changes in TP, TSP loading in surface runoff with time indicate a dynamic
physical biological chemical response for all treatments. This section discusses some of the
physical changes which occurred during the various precipitation series. Since many of the
physical effects of the different processes are competing, each will be described
individually with a composite effect described in the summary.
Surface Condition and Drying Time
The time between manure application and the first precipitation event produces to
substantial changes in TP, TSP loading. This effect decreases with an increasing number
of wet-dry cycles. Since the highest load potential is associated with surface applications
of manure, the time between surface manure application and the first precipitation event is
particularly important. During the growing season, evaporation rates for central New York
would vary from 1 to 4 mm/day. Therefore, a heavy (135 MT/ha) manure application to
the surface would require up to 15 days to reach an equilibrium water content of 10-15%.
Once drying of the surface manure pack is complete, surface residue will result in
decreased detachment energy at the soil surface and improved infiltration. Similarly,
incorporated manure will leave residue in the soil profile which enhances infiltration
characteristics. The laboratory and field studies demonstrated that precipitation events will
cause erosion and removal of surface residue and fine organic particles. In the extreme
case (300 day field observations), virtually all of the surface residue was transported off of
the plot area. Therefore, as the number of precipitation events following manure
application increase, the opportunities for surface residue to redistribute or be carried off
the plot are increased. Both infiltration and phosphorus concentration in surface runoff are
potentially affected by these processes.
The initial drying of surface applied manure is critical to the loading of phosphorus
in subsequent runoff events. With two to three days of drying at temperatures between 65
- 70°F and relative humidity of 40-55%, runoff volume and load were dramatically
reduced. In particular, four conclusions can be drawn from the laboratory and farm runs:
72
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simultaneous drying and shrinkage of surface applications caused increases
in infiltration and subsurface flow
although suspended solids concentrations were appreciably less, subsurface
concentrations (at 15 cm) were significantly greater
changes in trough moisture content and total moisture retention indicated an
immediate effect of incorporated manure
depth of application and type and quantity of bedding are very important in
determining surface residue, texture and subsequent loading values.
Precipitation to Initiate Runoff
The precipitation required to initiate runoff (PIR) clearly demonstrated the water
retention benefits of manure-treated soils (Figures 4.11 and 4.12). Although PIR values
increased with respect to the controls for all depths of incorporation, the relative increase of
the surface applied treatments for the field series was not as great as in series LG1-LG4.
This difference could be explained by the fact that much of the surface organic material and
residue was transported out of the 1.35 m^ field plot area during natural rainfall and
snowmelt events. This was particularly true with surface application plots where little
surface residue could be observed after 300 days.
Texture
Laboratory series LB1-LB6 utilized a Channery Bath soil, removed from an area
adjacent to the field plots. Unlike series LG1-LG4 coarse aggregates and stones were not
sieved. Similar to the field runs this soil reveals very good infiltration properties even for
the high intensity simulated rainfall events. The air-dried soil (7.1% moisture) yielded little
runoff during series LB1. This can be attributed to the very coarse textured unconsolidated
soil along with large aggregates and rocks allowing rapid water entry through the soil
surface.
Aggregation
Although aggregation was not specifically measured, this effect was observed for
several series treatments. Where soil manure aggregation is evident, macropores and
cracks in the surface would likely allow for greater infiltration or lessen the effect of surface
sealing. In addition, soil aggregation will likely have an effect on the raindrop detachment
energy required to dislodge and carry away soil-manure particles.
Suspended solids data indicate two competing processes. Initially, the mixing of
manure with silt loam soil caused higher suspended solids concentrations. As the mixture
dried, aggregation effects were visible and subsequent suspended solids concentrations in
surface runoff were less.
The effect of changes in density and packing can be observed as relatively high
suspended solids levels associated with greater incorporation depths. Although this trend
continues with time, increased aggregation of the manure soil mixture causes suspended
solids levels of all treatments to drop below control levels after 50 days.
pH in Surface Runoff
The manure amended soils produced a higher pH in surface runoff. In addition,
changes in pH were highly correlated with TSP concentrations in runoff samples for all
series runs. This relationship has important implications for control practices.
73
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300
200-
CM
£
tr
a.
100-
D
400
20
r
40
60
Time(days)
Figure 4.11
PIR, by rate, per unit area, all series
Time(days)
Figure 4.12
PIR, by depth, per unit area, all series
80
300-
PIR(l/m2)
(VD
O
0
. 1
100-
0-
-2
a
i
n 15cm
10cm
3cm
* Ocm
untreated
o
*
j ! i i . i
00 20 40 60 80
74
-------
Normalized Load
Minimal incorporation of 3 cm greatly reduced unit area! load. Although
normalized TP load from surface applications was almost three times that of the
incorporation treatments (Figure 3.32) for precipitation immediately following manure
application, this effect was reversed after a complete drying of the soil-manure pack.
Normalized loads were similar following three wet-dry cycles (series LG4) for all depths of
incorporation.
Normalized TSP load rates (Figure 3.33) were somewhat lower for higher rates of
application. However, residual losses at 54 days indicated slightly higher rates of TSP
losses for the higher application rate. This is likely the influence of higher mineralization
rates of the surface applied manure as evidenced by the relatively high TSP losses for the
surface applied case.
Changes in Nutrient Concentration within Events
Sample sequence was correlated with concentration of TP, TSP and TKN for
pooled data from all series runs (Figures 4.13-4.15). The slope of all curves indicates a
dilution effect after the initial high value associated with the first or second sample collected
immediately after manure application. Subsequent samples indicate lower values that
approach control levels after several wet-dry cycles. The time period between series varied
from 1 to 40 days thus allowing mineralization of nutrients in some case. This process
would explain the higher values of first samples collected after a break-in series (Figures
4.13-4.15).
WINTER CONDITIONS
Disposal of Manure on the Snowpack
The problem of manure application on the snowpack during periods when the snow
is actively melting was studied by Steenhuis (1977). The laboratory and field work
Steenhuis (1977) accomplished indicated that most of the nutrients in snow meltwater were
soluble. He further observed that unfrozen soils under snowpacks retained relatively good
hydrologic properties greatly reducing nutrient losses.
Steenhuis (1977) observed that the TP concentration in runoff was relatively low
due primarily to the low energy level of snowmelt events. In addition, he observed that
relatively small quantities of phosphorus were observed when manure was covered by the
snowpack. These losses were primarily controlled by fresh water movement in the
snowpack. He also observed that significant amounts of bedding increased phosphorus
adsorption and directly decreased phosphorus losses in runoff.
SUMMARY
Drying Effect
After the initial wetting of the manure-soil pack the treatments were allowed to dry
for time periods varying from 1 to 40 days. Depending on storage conditions the drying
effect resulted in significantly reduced loading for series runs LG3, LB5 and LBD1-LBD4.
Figure 4.16 illustrates this effect for the special case of surface applications. Series LBD1
was initially wetted two days after a high-rate manure application (135 MT/ha).
75
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20-
o>
E 10H
fb1(t=0) *
fb2(t=1d)
Ib1 (untreated)
Ib2(t=1d)
Ib3(t=2d)
Ib4(t=10d)
Ib5(t=25d)
approx. 20 min. between
samples within a series
5
0
5
10
15
sample number
Figure 4.13
Composite TP Cone., by sequence, all series
4-
3-
D>
1 -
fb1(t=0) *
fb2(t=1d)
Ib1 (untreated)
Ib2(t=0)
Ib3(t=2d)
Ib4(t=10d)
Ib5(t=25d)
'approx. 20 mln. between
samples within a series
aDD
-5
10
15
sample number
Figure 4.14
Composite TSP Cone., by sequence, all series
76
-------
120 n
100-
80 H
E 60 H
40-
20-
fb1(t=0) *
ft>2(t=1d)
Ib1 (untreated)
Ib2(t=2d)
Ib3(t=10d)
* approx. 20 min. between
samples within a series
-4
-202
sample number
Figure 4.15
Composite TKN Cone., by sequence, all series
77
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Subsequent rewetting of the soil-manure pack at 5,10 and 20 days resulted in flow
volumes which were appreciably higher than if the initial wetting were after a five-day
drying period (LBD2). Similarly, 10 and 20-day drying periods before initial wetting also
resulted in reduced runoff volumes. When drying conditions were riot favorable, similar
reductions in flow volume were not achieved until a 25-day period had elapsed (series
LG3).
Effect of Bedding
The fiber and solids content of manure is likely to have a significant effect on
surface condition following drying of the manure-soil pack. The manure collected from the
BIDS farm contained approximately 0.5 kg/cow /day of bedding. This is within the
expected range for freestall systems (0.4-0.9 kg/cow/day) reported by Safley (1978).
Since the quantity of bedding used in stanchion systems varies from 1.1-3.4 kg/cow/day
(Safley, 1978) this effect is important. The increased quantities of residue associated with
greater utilization of bedding (particularly straw) will result in a surface cover more closely
resembling surface conditions after reduced tillage operations.
Although time to initiate runoff is increased because of the relatively large quantity
of dry surface residue remaining after the soil manure pack dries, some of this effect may
be related to the fiber content of manure and its beneficial effect on surface infiltration
(Hafez, 1974). The influence of the fiber is twofold: it prevents a crusting of the surface
and it dissipates the energy of raindrop impact as any mulch cover would. Both of these
effects would improve the hydrologic response and conductivity of manure treated soils.
However, when surface applied manure dries, the light fine fiber component is mobile.
Not only was transport and deposition evident within the plot area but movement off the
plot was clearly evident after 300 days.
78
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SECTION V
FARM APPLICATIONS
TILLAGE-MANURE SYSTEMS
Although the principal objectives of conservation tillage and manure incorporation
are in conflict, tillage-manure systems can be developed which decrease TP and TSP
losses. The overall criteria in designing tillage-manure systems include:
evaluation of current practices
development of spreading schedules
special rate/incorporation practices (field renovation) for problem areas
short-term storage
tillage rotation systems
manure-soil testing
modified and experimental tillage systems
supporting practices
mobile evaluation systems
Current Practices
The daily spreading of manure is practiced on over 90% of Lake Ontario dairy
farms. Improvements in current spreading practices as well as adoption of new tillage-
manure systems will lead to reductions in total TP and TSP delivery.
The criteria for the location and rate of application of manure typically reflects
practical limitations on time, labor and location of spreading. Spreading activities are not
planned nor are they recorded. The result of these practices are poor uniformity of
application and little certainty with respect to nutrient additions from applications.
Development of Spreading Schedules
The concept of spreading schedules was introduced by Robillard and Walter (1979,
1983). This type of phosphorus control measure is particularly appropriate for the
problems associated with winter disposal. Specific applications of the spreading schedule
design involve three components:
identification of management periods
distribution of manure applications for phosphorus control and agronomic
constraints
identification of storage requirements and associated disposal systems.
Management Periods
The identification of management periods establishes possible differences in manure
disposal criteria. For example, in northern humid regions the following management
periods might be considered:
79
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Management Period Disposal Variables
Spring tillage rate of application, incorporation depth
Early crop stage growing season low application rates
Early fall after harvest rate of application
Fall tillage incorporation depth
Late fall before snowfall and frozen ground rate of application
Early winter period application area rate of application - low delivery areas
Late winter period low deli very areas
Spring thaw period storage - safe application areas
Special Rate/Incorporation Practices
Results of the laboratory, field and farm studies indicate that rate, depth and time
variables can be used to reduce total farm losses of TP and TSP. Specific practices which
would accomplish these objectives are:
field renovation (high application rates in no-till moldboard rotation)
safe disposal areas established with diversion terraces, berms, and
subsurface drainage as needed
high application rates to fields harvested for corn silage before winter
conditions
high application rates keyed to probable drying conditions after application
heavy rate strip applications which increase surface storage and allow
equipment traffic lanes
graduated rate applications.
Practical Implications
heavy repeated surface applications will prevent or limit frost development
and improve infiltration
on corn silage fields heavy manure applications before snowfall or frozen
ground will result in an improved hydraulic condition for winter and early
spring runoff events
during periods when delivery potential is high
spread on fields or areas where runoff and delivery potential are low
add straw or bedding material to absorb moisture
temporarily stockpile manure in a safe disposal area.
Short-term Storage
During periods of high snowfall, particularly in Oswego County, short-term
storage is currently practiced. Typically the storage method is simply a stacking system.
These systems do not necessarily result in reduced TP, TSP loading since there is generally
no complementary implementation of practices to divert runoff from upland watersheds
away from stacking areas.
Results from previous field studies (Robillard and Walter, 1983) indicate that high
losses and delivery of phosphorus are associated with three primary mechanisms:
precipitation or snowmelt immediately following surface applications
80
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manure applications during active thaw periods
poor disposal practices which enhance losses such as channelization of
runoff, stream crossings and poorly maintained equipment.
Tillage Rotation Systems
Reductions in TP, TSP loading can be achieved for Tillage-Manure Systems by the
use of high rate, uniform applications to fields in a no-till/moldboard tillage rotation. This
can be referred to as field renovation.
Typical daily manure spreading can be characterized as follows:
low rate, non uniform applications
disposal areas not sensitive to runoff potential
unplanned, unrecorded disposal practices.
The negative effects of this type of system are:
potentially high TP, TSP losses
uncertain nutrient contributions
lack of coordination with other tillage, agronomic practices.
When fields have been in no-till for several years high, uniform applications could
be made in the fall and late spring before the field is moldboard plowed. If convenient, two
or more moderate applications could be made between harvest and moldboard plowing.
The moldboard incorporation of manure and residues would act to interrupt weed and
insect cycles. In addition, nutrients would be redistributed throughout the root zone.
Finally, the heavy manure application would add appreciable amounts of residue to the soil
surface of fields harvested for corn silage.
Manure-Soil Testing
Good nutrient control practices will contribute to the achievement of reduced TP,
TSP loading and optimal crop production. Some nutrient control decisions can be made if
the following information is obtained:
manure testing for nutrient content
match available P crop requirement to P applications as closely as possible
use soil testing methods to anticipate quantity of P needed
if soil P levels are high, use starter P at planting only
if soil P levels are low, heavy uniform manure applications which are
immediately incorporated will increase soil P levels.,
Modified and Experimental Tillage Systems
There has been a dramatic rise in ridge-till planting (a 45% increase during the
1985-86 period). This increase demonstrates the new systems being adapted for unique
soil and climate problems.
Changes and adoption of reduced tillage systems are the key to their success,
particularly where adverse soil and climate conditions prevail. The design of tillage-manure
systems are no exception to this trend. The complexities of designing a flexible system to
81
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maintain residue cover and retain nutrients add an additional dimension to this adoption
process. Nonetheless, this study demonstrates the many alternatives available to satisfy
tillage, manure disposal and agronomic objectives on commercial dairy farms.
Supporting Practices
Practices which increase the accessibility to fields and/or decrease nutrient delivery
loss potential allow for more control over manure applications and scheduling. The
following examples could be considered supporting practices:
access roads which improve field accessibility during the winter period
farm road improvements which decrease rutting and channelization of water
upgrading and maintenance of spreading equipment to decrease spillage
during loading and transport and to increase the uniformity of application
changes in the use of bedding to absorb moisture or provide additional
surface residue (for example increasing the quantity of bedding used or
changing from fine wood sawdust to straw bedding).
Tillage-Residue Systems and the Development of Soil Frost
An element of winter spreading criteria involves the development and decrease in
soil frost. Benoit (1985,1986) points out the following physical characteristics of soil
frost development:
dry soil will freeze before a wet soil
frost depth decreases with increasing depth
the rate of freezing, the number of freeze-thaw cycles and the soil water
content at freezing influence the degree of soil structural modification caused
by freezing.
For the tillage-residue systems evaluated by Benoit (1985), the greatest sensitivity
of frost development were to changes in soil moisture, hydraulic conductivity and thermal
conductivity of frozen ground.
In this study, the plots with surface residue retained more snow than the non-
residue plots. In particular, fields which had been no-tilled retained more snow than fields
which had been fall chiseled.
For the tillage-residue systems studied by Benoit (1985,1986) small differences in
frost development occurred until the first snowfall event. From that time a direct negative
relationship existed between snow accumulation and frost depth.
Mobile Evaluation Systems
The numerous farm simulated rainfall runs completed with the PWSI unit in Wayne
and Oswego Counties verified the accuracy and flexibility of this type of evaluation system.
With a complete set of laboratory and controlled field data with which to reference farm
simulated precipitation runs, efficient evaluations of various manure-tillage systems can be
accomplished. This type of evaluation system not only improves upon existing methods
for comparing loads between various tillage manure systems but greatly enhances the
opportunity to observe practices on operating commercial farms. In addition, the mobile
evaluation system can be used to encourage innovation and experimentation among farm
82
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operators. The work in Wayne and Oswego Counties indicates that progressive farm
operators will demonstrate a keen interest and participation in the evaluation of new tillage-
manure systems.
Recommended Program Initiatives
As evidenced in the Wayne and Oswego County Tillage Demonstration Projects,
the initiatives and experimentation of individual farm operators are important elements of a
successful program. The initiatives take the form of equipment modifications,
nutrient/pesticide changes and adaptions in the timing of operations. The fact that these
new practices and adoptions are made in the context of existing farming operations means
that they should be looked at closely as part of the phosphorus control program.
The flexibility and timeliness of mobile monitoring units such as the PWSI unit
used for this study should be developed further. This type of evaluation technique should
be modified not only to investigate the many tillage-manure systems options cited in this
report but to develop instrumentation and methods for making winter and spring thaw
evaluations.
A second consideration with respect to program initiatives in the Great Lakes is the
linkage with groundwater monitoring and control. The interface between surface and
groundwater monitoring and control is obviously important but has been overlooked in
most cases to the detriment of both surface and groundwater program effectiveness.
Two separate conferences dealing with monitoring systems and surface-
groundwater interfaces would provide direction and coordination for these important
technical and policy questions. The emphasis of the monitoring systems conference would
be evaluation of control practices on different farms, soils and the conjunctive development
of practical field computer models. Ideally, model validation and control effectiveness
calculations would utilize direct monitoring observations.
Research Needs
The micro-climate effects of sunlight, soil and wind on the drying of surface
applied manure will likely result in appreciable differences in runoff potential and loading.
The key to minimizing loading potential would be to relate weather variables to loading
potential. These weather windows would key disposal to the probability of drying periods
and surface-groundwater loss potential. The application rate, incorporation depth and other
control variables would then change depending on time of year and hydrologic condition of
the soil.
83
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SECTION VI
CONCLUSIONS
Phosphorus is the limiting nutrient in many lake eutrophication processes. One
source of phosphorus is livestock manure which is applied to cropland. The potential for
relatively high TP and TSP loads in surface runoff has been associated with poorly
managed livestock disposal operations.
The utilization of herbicides in crop production provides opportunities for reducing
both tillage operations and soil erosion. The spectrum of tillage options varies from
conventional moldboard to the minimal soil disturbance of no till systems. In every case
nutrient losses from cropland are affected. There exists an inherent conflict between
maintenance of surface residue associated with reduced tillage systems and the
incorporation of manure to reduce losses of phosphorus in surface runoff. This research
addresses one aspect of these conflicting objectives by quantifying TP, TSP losses
associated with the application and incorporation of manure.
Elevated TSP losses have been linked to conservation tillage systems which result
in an accumulation of nutrients at the soil surface. Similarly, manure disposal practices
have been associated with elevated TP and TSP losses when manure is surface applied.
There are numerous alternatives for coordinating manure applications and conservation
tillage to minimize phosphorus losses. Application rate, incorporation depth, and time of
application all can be varied as well as the specific tillage system used. In addition, the
rotation of tillage operations in a sequence to accommodate manure disposal presents some
options to farm operators.
Laboratory, field and farm experiments were designed to accomplish the following:
observe phosphorus losses for a range manure application rates (22-135 MT/ha)
and incorporation depths (0-20 cm)
quantify changes with time which relate phosphorus load to various
combinations or rate depth treatments
incorporate the above results into practical recommendations for the development
of tillage-manure systems to control phosphorus losses.
The twelve rate-depth treatments used in the study represent a realistic range of
manure disposal options. Level 1 studies investigated the rate-depth-time relationship
under controlled laboratory conditions. Level 2 was conducted under more variable field
conditions and level 3 studies extended these results to various tillage-manure systems to
minimize phosphorus losses on operating dairy farms.
The results of all experimental runs indicated that runoff volume varied with the
time between initial manure application and the first precipitation event as well as with an
increasing number of wet-dry cycles. Runoff was as high as 81% of the 11.9 cm
simulated precipitation for events immediately following manure application and as low as
22% for the case of a relatively dry manure-soil pack. Depending on drying rates, initial
high runoff rates were greatly reduced after 5 to 25 days. After this period, manure-treated
soils typically produced a lower runoff volume than untreated plots. Respective mean TP,
TSP concentrations in surface runoff for all treatments was 7.7 and 2.1 mg/L. These
84
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concentrations are relatively high for cropland (Loehr, 1974). The corresponding loads
from experimental plots associated with the various series runs ranged from untreated
values(.09-4.0 hg/ha TP) for the high application rate (135 MT/ha) to the surface. A
relatively large fraction of this load (29-48%) was in a soluble form compared with
untreated plots which recorded a mean TSP/TP ratio of 0.13.
Initial high losses of TP and TSP in surface runoff are significantly buffered by
subsequent wet-dry cycles. After a two to five-day drying period, improved infiltration
and decreased concentration of TP, TSP can be observed for the manure-treated soils. A
complete drying of the soil-manure mixture results in increased soil moisture retention.
This effect was observed for all series runs. After a 25 to 50 day period, depending on the
number of wet-dry cycles and drying conditions, TP and TSP loading approached the
untreated case.
Changes in TSP concentration over time indicated the manure-amended soils caused
both a high initial flush of soluble phosphorus and a more sustained supply of soluble P in
surface runoff for subsequent precipitation events compared with the untreated plots. For
the case of 135 MT/ha application rate to the surface, there was a 30-fold increase in TSP
and a 10-fold increase in TP over the control. This ratio did decrease over time, but after
10 months residual TSP losses were typically still greater than the control.
Normalized loads indicated that loads from higher rate applications resulted in lower
losses per unit of manure applied. When normalized loads are compared by depth of
incorporation, the surface-applied case produced considerably higher losses.
The analysis of individual simulated precipitation events provides some information
which is useful in extrapolating to events of differing intensity and duration. Generally,
phosphorus concentration peaked within 30 minutes of the beginning of runoff.
Concentration then decreased exponentially for the remainder of the run, converging
toward a minimum value.
The dynamic loading changes from the initial application of manure to the first few
wet-dry cycles indicate the importance of observing and estimating phosphorus losses on
an event basis. After the soil-manure mixture had dried and been rewetted several times,
loading values did stabilize and approached untreated levels.
The application of manure to the surface resulted in an accumulation of surface
residue after several wet-dry cycles. This residue effect could explain, in part, the lower
runoff rates and mass losses associated with surface applications. This residue was light
and mobile causing a redistribution over the surface following each simulated precipitation
event and a movement off of field plots over a longer period.
fa
The controlled laboratory and field experiments of Phase I were extended to farms
in Wayne and Oswego Counties. Simulated precipitation was used to compare manure
application rate, incorporation depth, residue cover, tillage method, soil type and crop on
commercially operating dairy farms. The data from these studies were used to verify
preliminary Phase I findings and to observe how residue, tillage, soil type and crop cover
effect the basic rate-depth TP and TSP loads observed in Phase I.
85
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Results of simulated precipitation runs during the growing season indicated
appreciable differences between TP, TSP loading from areas with different residue cover,
manure application rates, cover crop and soil type.
The effect of residue cover was to decrease TP losses while TSP loads were
increased or remained at higher levels for longer time periods. Surface manure applications
and residue cover typically improved infiltration and water holding capacity. Although the
farm series runs were not able to accurately account for previous manure applications to
fields, the benefits of manure amended soils were reflected in relatively low TP loading
values.
Maintenance of a surface residue caused differences in surface runoff to be
relatively small between treatments even when manure was applied over the residue. For
events just two days after application of manure, TSP concentration was higher than the
levels observed on a bare soil. The high residual TSP load for manure over residue
suggests that sub residue soil conditions are favorable to the supply of soluble phosphorus
and that the process is flow controlled.
Crop and soil type did significantly effect TP, TSP loading with alfalfa indicating
lower losses of TP, TSP. Simulated precipitation runs on the clay loam soil indicated
higher runoff rates but lower TSP concentrations resulting in increased TP load and
decreased TSP load compared to the silt loam and sandy loam soils.
There was a high correlation between TSP concentration and TP concentration and
load for all farm series runs. In addition, TSP was a high fraction of TP load for all
manure amended soils, particularly surface applications.
The effects of drying and application rate were repeated in the farm series, although
the variation and trends of these series were not as clear as previous laboratory and field
runs. However, the farms series runs validated these results for the growing season,
indicating dramatically decreased TP, TSP load with four days of field drying before the
next precipitation event. In addition, normalized loads resulted in lower TP, TSP losses
for higher application rates. After four drying days infiltration for all soil types improved
with increasing surface application rate.
The development of tillage-manure systems to reduce TP, TSP loads are possible.
Management periods, application rates, incorporation, and storage are all elements of the
system. Special problem-oriented practices can be developed to deal with disposal
limitations and specific agronomic objectives. Finally, on-farm monitoring systems for
evaluating tillage manure alternatives should be used in conjunction with farm adoption and
experimentation for various tillage-manure practices.
Use of the sprinkling infiltrometer established control over several precipitation
variables (intensity, energy, droplet size) and provided an opportunity to look at some of
the physical processes influencing phosphorus losses independent of precipitation
variables. The loading data collected in the laboratory and field trials are consistent with the
concept of a shallow zone of interaction where phosphorus loss rates can be related to a
mass of interacting soil and water. This concept has been modeled and quantified by
Sharpley etal, (1981a). Their model relates accumulated phosphorus losses to initial soil
86
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phosphorus levels, time and the mass of water and soil interacting. The impact of the
rainfall on the soil surface determines the mixing depth. Typically, this mixing depth (zone
of interaction) is less than 1 cm and in some cases less than 1 mm.
Findings from all laboratory, field and farm trials result in several conclusions, all
having implications for the development of tillage-manure systems to minimize phosphorus
losses:
1. The runoff volume associated with manure application is strongly influenced
by the drying time between application and the first precipitation event.
2. The initial high runoff rates of manure-treated soils compared to the untreated
case are reversed 5-25 days after application under growing season
conditions.
3. TP and TSP concentrations exhibited a wide range, but typically decreased
exponentially from a high value associated with initial manure applications.
4. High TP and TSP loads are clearly associated with the first few precipitation
events following manure application.
5. The estimation or prediction of TP, TSP losses from manured cropland
should be accomplished on an event basis, particularly for the first few
precipitation events following manure application.
6. Incorporation depth explained much of the data variability for runoff volume,
TP, TSP concentration and loading, while manure application rates (22-135
MT/ha) appeared to have little effect.
7. Minimal incorporation (2-3 cm) of applied manure will greatly decrease losses
of TP and TSP in surface runoff.
8. Variations in mean TP, TSP concentrations within events indicate a dilution
effect after initial high concentration levels.
9. With 5-15 days of drying between precipitation events, some increase in the
TSP/TP ratio was noted. This change could reflect a higher rate of
phosphorus availability for the manure amended soils.
10. The amount of bedding in manure will influence residue cover for surface
manure applications. The benefits of this residue are similar to residues
associated with conservation tillage systems. However, the quality of this
cover is different with much of the residual bedding being transported off of
the application site over time.
11. After several wet-dry cycles during the growing season, losses of TP and
TSP in surface runoff appear to approach losses, observed in untreated soil.
During the non-growing season the number of wet-dry cycles required to
achieve this effect will be greater.
87
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12. Normalized TP, TSP data indicate lower losses per unit manure applied for
higher application rates.
13. The concept of a shallow surface zone of interaction appears consistent with
the loading data collected for all series runs. The accumulation of nutrients in
this zone and the physical mixing of soil and water during events can be
estimated for specific soils using the model developed by Sharpley ctal
(1981a). Surface conditions (texture, roughness, residue) are an important
element of this interaction zone.
14. There are many opportunities for meeting residue and incorporation objectives
within the context of farming operations are many, particularly if manure
spreading activities are integrated into a three to five-year tillage cycle.
15. The sprinkling infiltrometer is a promising instrument for the evaluation of
phosphorus losses for various tillage manure practices.
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APPENDIX A
INFILTROMETER REVIEW AND EVALUATION
A.I TYPES AND CHARACTERISTICS OF RAINFALL SIMULATORS REVIEWED
The two principle types of simulators that have been utilized for both laboratory and
field studies are the drop forming type and the sprinkling type.
In the construction of many of the simulators described below, natural rainfall
characteristics as reported by Laws (1941) and Laws and Parsons (1943) were used as an
important design criteria. In his original measurements, Laws (1941) reported terminal
velocities of 1-6 mm water drops from heights of 0.5 - 20 m. Together Laws and Parsons
(1943) investigated the drop size composition of natural rainfall at different levels of
intensity.
A. 1.1 Drop forming type simulators
Adams etal (1957) constructed a drop forming type infiltrometer for erosion
studies. The apparatus was set up to provide precipitation over a relatively small area (15
cm in diameter). Steinfordt and Hillel (1966) developed an infiltrometer delivering variable
' intensities of 4-100 mm/hr. In order to simulate the random distribution of natural rainfall
over the soil surface an eccentric rotor was linked to the drop forming module. The
simulator, as with many drop forming units, supplied large drop sizes and low impact
velocities which were unrepresentative of natural rainfall. However, Steinfordt and Hillel
(1966) point out that for their studies of surface sealing that the simulator was probably
adequate.
Both Blackburn etal (1974) and Munn and Huntington (1976) developed drop
forming type infiltrometers for field application. The velocity and energy characteristics of
the unit developed by Munn and Huntington (1976) were comparable to sprinkling
infiltrometers (Table A.I). The uniformity of drop sizes was cited as the principal
difference between the drop forming and the sprinkling type.
Romkens etal (1975) improved the uniformity of application of drop forming
simulators by super-positioning three motions of a closely packed unit of hypodermic
needles. The system also allowed variation of drop diameter by changing needle size and
storage volume. Selby (1970), Hamon (1978), Kleijn etal (1979) and Walker etal (1977)
all improved drop forming units to more closely match natural rainfall characteristics. In
particular, Kleijn extended many of the empirical studies of drop forming characteristics by
relating flow rate of drop formers to drop size parameters. In addition, Kleijn (1979) used
a cam and slotted disk mechanism to simulate non-repetitious movement and improve the
uniformity of application. Walker etal (1977) achieved 95% of the terminal velocity and
comparable energy characteristics by constructing a tower of 12.3 m in a laboratory.
In general the limiting factors in utilizing drop forming simulators has been
achieving terminal velocities and uniformity of application. As a result, researchers have
more commonly used sprinkling-type infiltrometers.
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A. 1.2 Sprinkling type infiltrometers
An early sprinkling-type infiltrometer using a full cone commercial nozzle was
developed by Castel (1956). Bertrand and Parr constructed the Purdue-type sprinkling
infiltrometer in 1961. Dixon and Peterson modified this unit in 1964 and 1968 while
Amerman (1970) made further improvements in 1970. Anderson etal (1968) utilized the
basic design of Bertrand and Parr (1961) to apply precipitation to a 35.7m2 area which is
considerably larger than the 1.35m2 plot area of Bertrand and Parr. Turner and Langford
(1969) determined that the most important factors influencing drop size were:
nozzle type,
position in the area wetted,
operating pressure, and
height of the nozzle above the test surface
TABLE A. 1
Simulator
Meeuwig
Adams
McQueen
Type-F
Blackburn
Sprinkling
Tahos Basin
Rainulator
Plot
Area
m2
0.34
0.067
0.067
7.4
0.84
1.48
0.37
16.7
Drop
Diameter
mm
3.00
5.56
5.61
nozzle
3.00
nozzle
3.20
nozzle
Height of
Drop Fall
m
0.42.5
1.04.3
L55.2
pressure
2.15.5
pressure
2.55.9
pressure
Drop
Velocity
m/s
3.1 x 105
9.2 x 105
1.4xl06
variable
1.5 xlO6
variable
1.7x 106
variable
KJ per Unit
Volume
J/ha-cm
1.5 x 106
1.6xl06
6.2 x 106
(after Munn and Huntington, 1976)
Utilizing this criteria they determined that the Meyer and McCune (1958) simulator
using a Veejet 80100 (Spraying Systems) nozzle open downwards at a pressure of six
p.s.i. from a height of 2.4m gave the most acceptable drop size and velocity spectra and
uniformity of application. Turner and Langford (1969) also postulated that if actual
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discharge rates were too high that the spray period should be changed and not the
discharge.
Shriner etal (1977) designed an infiltrometer which could supply intensities of 0.5
to 2.7 cm/hr, a drop size of 0.1-3.2 mm and the system was completely programmable.
Zegelin and White (1982) utilized an electronically pulsing solenoid valve between a
pressurized water supply and the nozzle to simulate natural rainfall of varying intensity.
They used full jet nozzles (Spraying Systems) with a wide angle full cone spray pattern.
Foster etal (1982) used simultaneously oscillating nozzles with intermittent pulse sprays to
achieve variable precipitation intensity. As with Turner and Langford (1969) and Zegelin
and White (1982), Foster et al (1982) point out the importance of changing application time
to achieve intensity levels rather than change flow/pressure relationships at the nozzle.
However, Sloneker and Moldenhauer have pointed out that the energy to initiate runoff
eventually increases as the nozzle off time becomes larger. Like Meyer and McCune
(1958), Foster etal (1982) used a Veejet 80100 nozzle with impact velocity nearly equal to
the velocity from natural raindrops when the nozzle was placed 2.4 m above the soil
surface. The drops produced by the Foster etal (1982) unit were slightly smaller than
natural raindrops with kinetic energy about 75% of natural precipitation.
Pulses of spray were generated and controlled by an industrial process controller
programmed specifically for the drop size, velocity and intensity characteristics required for
each run.
In summary, there appears to be many advantages of sprinkling type infiltrometers
over the drop forming type:
the availability of numerous nozzle types from commercial suppliers
pressure and flow regulation for specific nozzles offer unlimited droplet size,
velocity profiles, and intensity ranges
since all systems are pressurized, the fall height required to achieve near
terminal velocities is less than the drop forming units
for certain nozzles the uniformity of application is much better than drop
forming units.
A.2 THE PURDUE-WISCONSIN TYPE SPRINKLING INFILTROMETER
The availability of a Purdue-Wisconsin-type sprinkling infiltrometer was fortunate
for a number of reasons.
based on the preceding literature review it was concluded that the sprinkling
infiltrometer had several advantages over the drop forming units
the Purdue-type infiltrometer developed by Bertrand and Parr (1961) was the
culmination of an extensive literature review and experimentation with various
nozzle types and pressure/flow regulation
several investigators had used the Purdue type infiltrometer inspiring
modifications and improvements, particularly those changes accomplished by
Dixon and Peterson at the University of Wisconsin
rainfall and energy characteristics of nozzles used with the Purdue-type
infiltrometer have been reported by other investigators.
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A.2.1 Development and Modifications
Bertrand and Parr (1961) tested 24 different nozzles for drop size and drop
distribution at various combinations of pressure and height. Of the 24, six nozzles met the
criteria for distribution uniformity and intensity. These nozzles were then tested further for
drop size distribution, drop velocity and kinetic energy. These tests resulted in the
selection of three nozzles which were full-cone, medium angle, center-jet type nozzles.
When operated at the indicated pressure and height they provided the following levels of
intensity (Table A.2):
Table A.2
Nozzle
5B
5D
TLA
Height
(m)
2.7
2.7
2.7
Pressure
(psi)
6
9
6
Intensity
(cm/hr)
6.4
8.3
11.4
Dixon and Peterson (1964) made several modifications to the infiltrometer
developed by Bertrand and Parr (1961) including changes in the pumping unit, nozzle
pressure control system, runoff collection system, runoff measuring system, tower and
cover, and spray nozzle assembly. Later Dixon and Peterson (1968) designed a vacuum
runoff collection system which eliminated much of the excavation required for field
operation. Amerman etal (1970) designed a rotating disk to achieve variable intensities for
a given nozzle without changing drop size and velocity profiles.
A.2.2 Possible Modifications of the Purdue-Wisconsin Simulator
An improved system for regulating pressure and intermittent operating times is
important. The addition of a timer and electronically pulsing solenoid valve as described by
Zegelin and White (1982) should be investigated. The addition of a rotating disk first
described by Amerman etal (1970) and later by Rawitz etal (1972) and Grieson and Oades
(1977) would increase control options. The modifications of the water distribution system,
nozzle mounting procedure, and external sensing of vacuum collected runoff described by
Rawitz etal (1972) should also be evaluated. Finally the programming controls designed
by Foster et al (1982) and data handling system developed by Chow and Ten (1974) would
likely improve the operating efficiency of the system and data management.
The canopy-runoff collection system should be streamlined. The canopy frame
should be constructed of light weight aluminum and the canvas material replaced by nylon.
The frame should be collapsible and supported from the supply wagon rather than self
supporting. Similarly the runoff collection system should be mounted on the supply
wagon to eliminate the very difficult and tedious set up.
The supply wagon should be equipped with wide track tires and the recirculation
system improved to capture all precipitation except that directly falling on the plot and a
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narrow border area. The weight of the supply wagon should be used to hydraulically press
the plot frames into the soil at the desired location.
The data recording system should be upgraded to collect flow data, on-line analysis
of suspended solids, pH and selected ions. All data including flow weighted
concentrations and loading calculations should be recorded on discs for later analysis or
modelling purposes.
Overall, the PWSI unit should be modified to allow one-person operation with the
capability of 15-20 runs per day. Finally, the unit could incorporate equipment to collect
groundwater samples under a plot area which is under simulated rainfall or ponding
conditions.
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APPENDIX B
PWSI OPERATING CHARACTERISTICS AND PROCEDURES
This appendix lists the components and operating characteristics of the Purdue-
Wisconsin Sprinkling Infiltrometer (PWSI) unit used in all laboratory and field evaluations:
PWSI Components --
The principle component in the PWSI unit is the nozzle. The criteria used in
evaluating a nozzles performance include:
uniform drop distribution over the plot area
drop velocity approaching terminal velocity
total energy values similar to natural rainfall
The 7LA nozzles used in all laboratory and field runs indicated a small coefficient of
variation (4.04%) and total kinetic energy dissipated at the soil surface was similar to
natural rainfall. The distribution of droplet size is given in Table B.I. The concentration of
droplets in the 1.5-3.0 mm range is consistent with sizes expected from natural rainfall.
TABLE B.I
DISTRIBUTION OF DROPLET SIZES FOR 7LA NOZZLE
SIZE RANGE PERCENT
(mm)
>3.32 1.0
3.326-2.744 5.1
2.793 - 2.362 6.7
2.361 - 1.651 19.3
1.650-1.410 10.3
1.409 - 1.168 8.3
1.167-0.833 13.9
.832-0.147 20.1
< 0.146 14.8
Other operating characteristics of the 7LA nozzle include:
total Area of Application - 3.32 m radius centered below the plumb line of
the nozzle
intensity vs. pressure - Figure B.I indicates total flow volume at various
nozzle pressures.
The 12 gauge galvanized plot frames cover a total area of 1.35 mm2. An angle iron
driving frame is used to drive the frames 3-5 cm into the soil. A collection T made of 1.25
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cm perforated copper tubing and 2.0 cm rubber hose was used to collect runoff and direct it
through the rubber hose to the runoff collection tank.
The runoff collection system was designed and constructed by Dixon and Peterson
(1964,1968) and essentially replaced the system constructed by Bertrand and Parr (1962).
The collection tank consisted of a 302L steel pressure tank equipped with a Belfort FN1
portable level recorder (12-hour chart). The vacuum in the tank is driven by a single
cylinder, single stage air compressor which is powered by the 3.5 Briggs and Stratton
engine.
The telescoping aluminum tower is constructed of 2.54 cm and 3.18 cm pipe. The
telescoping legs are adjusted to the desired height with friction valve collars. The canvas
cover is cut specifically in the shape of a truncated pyramid to minimize wind effects during
operation.
The water supply and reticulation system provides a gravity feed from the supply
tanks to a 3.8 cm centrifugal pump which directs the flow to a 7.6L pressure tank which, in
turn, directs flow through a rubber hose and the 7LA nozzle. Monitoring of line pressures
and the pressure at the nozzle head is provided through farm pressure gauges.
Operating Procedures -
The procedure involved for one run (one trough) is described below:
trough is transported from storage to weighing station using a dolly
weight recorded prior to rainfall simulation run
trough is transported from weighing station to rainfall simulation area
using steel blocks under flange, trough is placed at a 2% slope
height of 7LA nozzle is adjusted so that nozzle tip is 2.74 m above soil
surface of trough
plumb line is used to check that nozzle is directly above trough center
height and plumb procedures are repeated until proper alignment is achieved
sheet metal lid is placed over trough
590 mL Malgene subsurface sample bottle is placed in sheet metal support
hook and connected to trough drainage tube
engine and pump are started
supply valve is turned on
pressure at nozzle head is adjusted to six p.s.i.
lid is removed from trough
plastic raingauges are introduced next to trough
runoff collection tank is checked to be sure vacuum pressure is increasing-
A summary of operating systems constants are provided in Table B.2.
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TABLE B.2
PWSI OPERATING SYSTEMS CONSTANTS
SYSTEM COMPONENT CONSTANT
Lab Trough Area 0.186m2
Field Plot Area 1.35 m2
Application Area 8.04 m2
Precip/Tank Ratio 0.18/1.0 unit
Operating Suction 60-90 mm Hg
Line Pressure 2-10 psi
Nozzle Set 6 psi, 9' above plot
Water Supply 3780L.
Chart Conversion, Flow, (AY) 3.029 L
, Time (AX) 5.0 = time
Coefficient of Variation of Application 4.04%
Field Plot Conversion to Acres 30,000
Aluminum Tower base 12'xl2', top 8'x8'
103
* U.S. G.P.O.:1991-281-724:43567
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TECHNICAL REPORT DATA
1. REPORT NO. Z
EPA-905/9-91-006C
4. TITLE AND SUBTITLE
Agricultural Nonpoint Source Control of Phosphorus in the New York State
Lake Ontario Basin
Volume III- The Influence of Tillage on Phosphorus Losses From
Manured Cropland (1987)
7. AUTHOR(S)
Paul D. Robillard
Michael F. Walter
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Agricultural Engineering
Cornell University
Ithaca, NY 14853
12. SPONSORING AGENCY NAME AND ADDRESS
Great Lakes National Program Office
U.S. Environmental Protection Agency
230 South Dearborn Street
Chicago, Illinois 60604
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
1987
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
A42B2A
11. CONTRACT/GRANT NO.
R005725
13. TYPE OF REPORT AND PERIOD COVERED
Final-(1985-1986)
14. SPONSORING AGENCY CODE
GLNPO
IS. SUPPLEMENTARY NOTES
Ralph Christensen, USEPA Project Officer
John Lowrey, Technical Assistant
16. ABSTRACT
A sprinkling infiltrometer was used to evaluate total phosphorus (TP) and total soluble phosphorus (TSP) losses in surface runoff from plots receiving manure
application rates of 22-135 MT/ha and from plots where manure had been incorporated to depths varying from 0-20 cm. Both laboratory and field trials were
conducted utilizing simulated precipitation. Infillrometer runs were repeated for various drying conditions of the soil manure mixture at time intervals varying from 1-
30 days.
Significantly higher TP and TSP loads in surface runoff were associated with surface applications of manure immediately followed by a precipitation event. For the
standard 12-cm, 60-minute event, TP and TSP loads were as high as 13.4 and 7.7 kg/ha, respectively. These loads were 20-25 times greater that observed TP, TSP
loads from control plots. Typically, the high loading rates were short-lived with the positive effects of manure amendments on infiltration, moisture retention and
phosphorus sorption being observed after drying periods of 5-25 days. Generally, after several wet-dry cycles TP, TSP loads approached control levels.
The sprinkling iafiltrometer provides the basis for a promising method of on-sile evaluation of tillage-manure systems. The versatility of such an instrument in a
laboratory and field setting is advantageous. Tillage-manure systems and other phosphorus control measures can be accurately compared using such techniques. Lastly,
the accumulation of a data bank from infiltrometer runs provides a basis for more comprehensive comparisons of tillage-manure phosphorus control options.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTIONS b. IDENTIFIERS/OPEN ENDED TERMS
Manure
Phosphorus
Nitrogen
Nutrients
Runoff
Tillage
Cropland
18. DISTRIBUTION STATEMENT 19. SECURITY CLASS (This Report)
Document available to the public through the National None
iccnnica Intormation ocrvicc,IX ILo SECURITY CLASS (This page)
Springfield, VA 22161
None
EPA Form 2220-1 (Rev. 1-91) PREVIOUS EDITION IS OBSOLETE
c. COSATI Field Group
21. NO. OF PAGES
118
22. PRICE
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