The Walkerton Inquiry
Commissioned Paper 6
The Management of Manure in Ontario
with Respect to Water Quality
By
Michael J. Goss, Kimberley S. Rollins, Kenneth McEwan,
J. Ralph Shaw, and Helen Lammers-Helps
Toronto
2002
© Queen’s Printer for Ontario, 2002
Published by Ontario Ministry of the Attorney General
This paper and other Walkerton Inquiry Commissioned Papers are available on the
Walkerton Inquiry CD-ROM and at <www.walkertoninquiry.com> with the complete
final report.
General editor, Commissioned Papers: Sheila Protti
Editor: Rosemary Tanner, with Lynda Lyons
Proofreader: Lynda Lyons
Design: Madeline Koch, Wordcraft Services; Brian Grebow, BG Communications
The Management of Manure in Ontario with Respect to Water Quality
i
Abstract
This paper provides an account of current manure management in Ontario
with reference to impacts on the quality of water sources used for drinking.
Section 1 highlights those manure components that have the potential to result
in the contamination of drinking water. Section 2 covers the regulatory
framework governing manure management and the biophysical processes that
govern the potential risks to water resources. We compare current regulations
in Ontario with those in other parts of Canada, North America, and Europe.
In section 3, we identify the current understanding of how the quality of water
resources can be impacted by manure at different stages of the management
system. And section 4 provides an assessment of the potential changes in manure
production in Ontario over the next decade, both in terms of amount and its
distribution. In documenting the information that underpins management
options, we have taken account of the literature from other areas of North
America and Europe.
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Walkerton Inquiry Commissioned Paper 6
About the Authors
Dr. Michael J. Goss, a specialist on the impact of agriculture on the environment,
is Professor and Chair of Land Stewardship, Centre for Land and Water
Stewardship, University of Guelph, Ontario.
Dr. Kimberly S. Rollins, a specialist in environmental and natural resource
economics, is Associate Professor in the Department of Agricultural Economics
and Business at the University of Guelph.
Kenneth McEwan, B.Sc.(Agr), M.Sc., a specialist in agricultural production
economics, is a College Professor in the Agricultural Economics and Business
Department at Ridgetown College, University of Guelph.
J. Ralph Shaw, is President of J & R Shaw Inc., an agri-food management
consulting company. He was formerly a branch director with the Ontario
Ministry of Agriculture, Food and Rural Affairs, responsible for advisory services
related to all aspects of crop production and soil management.
Helen Lammers-Helps, B.Sc. (Agr.) is a freelance writer. She was the Assistant
Manager of the Soil and Water Conservation Information Bureau at the
University of Guelph and worked as a soil conservation adviser for the Ontario
Ministry of Agriculture.
The Management of Manure in Ontario with Respect to Water Quality
iii
Contents
1 Introduction ............................................................................................ 1
2 Regulations, Policies, and Management Guidelines
Governing Manure Management and Water Protection ......... 14
2.1 Introduction ................................................................................. 14
2.2 Goals of Regulation and Types of Regulatory Devices .................. 16
2.2.1 Goals of Regulation ......................................................... 16
2.2.2 Types of regulatory instruments ....................................... 21
2.2.2.1 Command-and-control direct regulation ........... 22
2.2.2.2 Voluntary approaches ........................................ 22
2.2.2.3 Market-based economic instruments ................. 25
2.2.3 The Role of Individual Producer Discretion..................... 27
2.2.4 Coordinated Strategies ..................................................... 28
2.3 United States ................................................................................ 30
2.3.1 Overview of Relevant U.S. Environmental
Regulations ...................................................................... 31
2.3.2 U.S. Regulations, Acts, and Programs Designed to
Protect Groundwater ....................................................... 34
2.3.3 Animal Feeding Operations Guidelines and
Regulations ...................................................................... 35
2.3.4 Livestock Waste Runoff and Non-point Source Pollution
Policies ............................................................................. 36
2.3.5 Regulation of Point Source Pollution
from Livestock Waste ....................................................... 37
2.3.6 USDA-USEPA Unified National Strategy for Animal
Feeding Operations (AFOs) ............................................. 39
2.3.6.1 Voluntary programs for AFOs ........................... 40
2.3.7 Federal Financial Assistance for Animal Waste
Management .................................................................... 41
2.3.8 Best Management Practices (BMPs) Recommended in
the United States .............................................................. 45
2.3.9 State-level Regulations for Non-point Source
Pollution77 ...................................................................... 51
2.3.10 State Livestock Waste Management Regulations
in Kentucky ..................................................................... 52
2.3.11 State Livestock Waste Management Regulations
in New York ..................................................................... 55
2.4 Regulations and Policies in Europe ............................................... 57
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Walkerton Inquiry Commissioned Paper 6
2.5 Regulations and Policies in Canada .............................................. 59
2.5.1 New Brunswick ............................................................... 60
2.5.2 Quebec ............................................................................ 61
2.5.3 Ontario ............................................................................ 63
2.5.3.1 Best Management Practices in Ontario .............. 68
2.5.3.2 Key statements from OMAFRA publications ...... 72
2.5.3.3 Siting of livestock facilities in relation to land
under different usage ......................................... 72
2.5.3.4 Manure handling and storage ............................ 73
Types of storage ............................................................... 74
2.5.3.5 Land application ............................................... 75
3 Biophysical Aspects of Manure Management ............................ 83
3.1 Background .................................................................................. 83
3.2 Potential Contamination and Manure Management Phase ........... 85
3.2.1 Feed manipulation ........................................................... 85
3.2.1.1 Summary........................................................... 93
3.2.2 Excretion ......................................................................... 93
3.2.2.1 Direct excretion into water resources ................. 94
3.2.2.2 Excretion in confined or sheltered areas ............. 95
3.2.2.3 Mineral nutrients and labile carbon
compounds ....................................................... 96
3.2.2.4 Metals ............................................................... 98
3.2.2.5 Pathogens ........................................................ 100
3.2.2.6 Endocrine-disrupting substances ..................... 108
3.2.2.7 Summary......................................................... 110
3.2.3 Initial handling of manure and its short-term storage..... 110
3.2.3.1 Nutrients ......................................................... 111
3.2.3.2 Pathogens ........................................................ 112
3.2.3.3 Summary......................................................... 112
3.2.4 Long-term manure storage ............................................. 113
3.2.4.1 Fate of manure nutrients during storage .......... 116
3.2.4.2 Fate of pathogens ............................................ 121
3.2.4.3 Metals ............................................................. 122
3.2.4.4 Summary......................................................... 123
3.2.5 Processing and treatment ............................................... 124
3.2.5.1 Composting .................................................... 124
3.2.5.2 Other processing treatments ............................ 126
3.2.5.3 Summary......................................................... 127
The Management of Manure in Ontario with Respect to Water Quality
3.2.6
v
Direct deposition and application of manure
to the land ..................................................................... 127
3.2.6.1 Direct deposition ............................................ 128
3.2.6.2 Application to land ......................................... 129
3.2.6.3 Summary......................................................... 139
3.2.7 Fate of manure components applied to the soil .............. 140
3.2.7.1 Nitrogen ......................................................... 140
3.2.7.2 Phosphorus and other nutrients ...................... 143
3.2.7.3 Metals ............................................................. 145
3.2.7.4 Bacteria ........................................................... 146
3.2.7.5 Viruses ............................................................ 148
3.2.7.6 Endocrine-disruptive compounds .................... 149
3.2.7.7 Summary......................................................... 150
3.2.8 Contamination of water resources .................................. 151
3.2.8.1 Nitrate ............................................................ 151
3.2.8.2 Phosphorus ..................................................... 152
3.2.8.3 Bacteria ........................................................... 153
3.2.8.4 Endocrine-disruptive compounds .................... 155
3.2.8.5 Summary......................................................... 156
3.3 Transport Processes ..................................................................... 157
3.3.1 Water partitioning at the soil surface .............................. 157
3.3.1.1 Summary......................................................... 159
3.3.2 Basic equations governing transport through the soil ..... 159
3.3.2.1 Summary......................................................... 160
3.3.3 Contaminant characteristics relevant to
their transport ................................................................ 161
3.3.3.1 Summary......................................................... 162
3.3.4 Preferential flow and solute transport ............................. 162
3.3.4.1 Summary......................................................... 167
3.3.5 Transport of contaminants from manure........................ 167
3.3.5.1 Nitrogen ......................................................... 168
3.3.5.2 Phosphorus ..................................................... 171
3.3.5.3 Metals ............................................................. 173
3.3.5.4 Bacteria ........................................................... 174
3.3.5.5 Protozoa .......................................................... 178
3.3.5.6 Endocrine-disrupting compounds ................... 179
3.3.5.7 Summary......................................................... 179
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Walkerton Inquiry Commissioned Paper 6
3.3.6
Predicting contamination of water resources
by components of manure ............................................. 179
3.3.6.1 Summary......................................................... 180
3.4 Future Research Needs ............................................................... 181
3.4.1 Summary ....................................................................... 183
4 Manure Production in Ontario ..................................................... 184
4.1 Background ................................................................................ 184
4.2 Objectives .................................................................................. 184
4.3 Methodology .............................................................................. 185
4.4 Results ........................................................................................ 187
4.4.1 Farm Structure ............................................................... 187
4.4.2 Livestock Farm Numbers ............................................... 189
4.4.3 Historical Livestock Numbers ........................................ 189
4.4.4 Livestock Units and Manure Production per
County/Municipality ..................................................... 192
4.4.5 Manure Application ....................................................... 203
4.5 Livestock and Manure Projections .............................................. 205
4.5.1 Dairy Farmers of Ontario .............................................. 205
4.5.1.1 Animal Numbers in Next 5–10 Years .............. 205
4.5.1.2 Future Production Facilities ............................ 206
4.5.1.3 Manure Production ......................................... 206
4.5.1.4 Technological Advances ................................... 206
4.5.1.5 Demand for Product ....................................... 207
4.5.2 Ontario Pork Producers’ Marketing Board ..................... 207
4.5.2.1 Animal Numbers in Next 5–10 Years .............. 207
4.5.2.2 Future Production Facilities ............................ 207
4.5.2.3 Manure Production ......................................... 207
4.5.2.4 Technological Advances ................................... 208
4.5.2.5 Demand for Product ....................................... 208
4.5.3 Chicken Farmers of Ontario .......................................... 209
4.5.3.1 Animal Numbers in Next 5–10 Years .............. 209
4.5.3.2 Future Production Facilities ............................ 209
4.5.3.3 Manure Production ......................................... 209
4.5.3.4 Technological Advances ................................... 210
4.5.3.5 Demand for Product ....................................... 210
4.5.4 Ontario Egg Producers................................................... 210
4.5.4.1 Animal Numbers in Next 5–10 Years .............. 210
4.5.4.2 Future Production Facilities ............................ 210
4.5.4.3 Manure Production ......................................... 211
The Management of Manure in Ontario with Respect to Water Quality
vii
4.5.4.4 Technological Advances ................................... 211
4.5.4.5 Demand for Product ....................................... 211
4.5.5 Ontario Turkey Producers’ Marketing Board .................. 212
4.5.5.1 Animal Numbers in Next 5–10 Years .............. 212
4.5.5.2 Future Production Facilities ............................ 212
4.5.5.3 Manure Production ......................................... 212
4.5.5.4 Technological Advances ................................... 212
4.5.5.5 Demand for Product ....................................... 212
4.5.6 Ontario Cattleman’s Association .................................... 213
4.5.6.1 Animal Numbers in Next 5–10 Years .............. 213
4.5.6.2 Future Production Facilities ............................ 213
4.5.6.3 Manure Production ......................................... 213
4.5.6.4 Technological Advances ................................... 214
4.5.6.5 Demand for Product ....................................... 214
4.5.7 Conclusion .................................................................... 214
4.5.8 National Perspective....................................................... 214
4.5.8.1 Beef ................................................................. 215
4.5.8.2 Swine .............................................................. 215
4.5.8.3 Poultry and Egg .............................................. 215
4.5.8.4 Dairy ............................................................... 216
4.5.9 Livestock Projections for Ontario by Industry Analysts .. 216
4.5.10 Industry Trendlines ......................................... 216
4.5.10.1 Swine Projections ............................................ 218
4.5.10.2 Cattle Projections ............................................ 218
4.5.10.3 Poultry Projections .......................................... 218
4.5.11 Ontario Manure Growth Rates ....................... 220
4.6 Summary .................................................................................... 221
Appendix 4.1: Coefficients Used to Calculate
Livestock Units .................................................................................. 225
Pigs ..................................................................................................... 225
Cattle (including beef and dairy) ........................................................ 225
Poultry ................................................................................................ 226
Appendix 4.2: Questionnaire for Producer Organizations ...... 227
Producer Organizations ...................................................................... 227
Appendix 4.3: Calculation of Manure, Nitrogen,
Phosphorus, and Potassium Production .................................. 228
Pigs ..................................................................................................... 228
Cattle.................................................................................................. 228
Poultry ................................................................................................ 229
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Walkerton Inquiry Commissioned Paper 6
Appendix 4.4: Number of Livestock Farms per County/
Municipality, 1996 ........................................................................... 230
Appendix 4.5: Livestock Head, Livestock Units, and
Manure Production by County/Municipality
in 1986, 1991, and 1996 ............................................................... 231
Appendix 4.6: Total Livestock Units and Manure Produced
in Six Counties/Municipalities and Their Respective
Townships, 1986, 1991, 1996 ...................................................... 239
Appendix 4.7: Nitrogen, Phosphorus, and Potassium
Production in Ontario Counties/Municipalities,
1986, 1991, 1996 ............................................................................ 254
Appendix 4.8: Livestock Numbers per Tillable Hectare
and Manure Application Method as a % of Tillable
Land, 1996 ......................................................................................... 259
Appendix 4.9: Livestock Numbers, Livestock Units, and
Manure Production Predictions ................................................... 261
References .............................................................................................. 263
The Management of Manure in Ontario with Respect to Water Quality
ix
Tables
Table 1-1
Table 2-1
Table 2-2
Table 2-3
Table 2-4
Table 2-5
Table 2-6
Table 2-7
Table 2-8
Table 3-1
Table 3-2
Table 3-3
Table 3-4
Table 3-5
Table 3-6
Table 3-7
Table 3-8
Table 3-9
Table 3-10
Annual Water Balance Components (mm) at Four Sites in
Ontario for the Period 1961 to 1990 (average ± standard
deviation) ............................................................................. 7
Environmental Stringency Ranking of Environmental
Regulations for the Hog Industry ....................................... 17
U.S. Programs Providing Financial and Technical
Assistance for Animal Waste Management ......................... 43
Selected Practices Installed with EQIP Assistance and
Average Installation Costs ($US) ........................................ 45
Penalty Structure for Infractions of Quebec’s Livestock
Waste Handling Regulation ............................................... 63
Summary of General BMPs for Applying Nutrients
to Crops ............................................................................. 70
BMPs for Timing of Application ........................................ 76
Potential for Surface Water Contamination from
Manure Runoff .................................................................. 78
Minimum Separation Distances to Water Sources for
Surface Water Contamination Potential from Liquid and
Solid Manure Runoff ......................................................... 82
Feed-related Measures Contributing to the Reduction in
Pollution Caused by Animal Production ............................ 86
Characteristics of Different Types of Manure in Ontario .... 96
Manure Production and Characteristics (per 1,000 kg Live
Animal Weight per Day)† .................................................. 97
Range of Metal Content of Manure from Swiss Farms ....... 98
Copper and Zinc Content of Liquid Manure from
Different Animal Categories .............................................. 99
Examples of Pathogenic Bacteria Found
in Animal Manure ........................................................... 100
Frequency of Detection of Pathogenic Organisms
in Cattle ........................................................................... 101
Examples of Bacterial and Protozoa Numbers in Some
Animal Manure ................................................................ 102
The Frequency of Detection of E. coli O157 in Animals
from Different Groups ..................................................... 103
Relative Potency of Some Endocrine-disruptive
Substances ........................................................................ 108
x
Table 3-11
Table 3-12
Table 3-13
Table 3-14
Table 3-15
Table 3-16
Table 3-17
Table 3-18
Table 3-19
Table 4-1
Table 4-2
Table 4-3
Table 4-4
Table 4-5
Table 4-6
Table 4-7
Table 4-8
Table 4-9
Table 4-10
Table 4-11
Table 4-12
Walkerton Inquiry Commissioned Paper 6
Concentration of Endocrine-disruptive Substances in
Animal Manure ................................................................ 109
Characteristics of Fresh and Anaerobically Fermented
Pig Slurry ......................................................................... 118
Composition of Animal Dungs: Fresh and After
Seven Months’ Aerobic or Anaerobic Storage ................... 118
Characteristics of Poultry Manure Sampled at Different
Depths in Deep-pit Storage .............................................. 119
Survival of Potentially Pathogenic Organisms in Manure . 121
Typical Nutrient Content of Finished Compost
from Manure ................................................................... 124
Comparison of Different Methods of Manure Application
on the Losses of Ammonia by Volatilization ..................... 132
Sinks for N Following Application of Slurry .................... 136
Average Migration Velocity and Velocity Relative to Average
Pore Water for Bacteria from Contrasting Manures .............. 176
Profile of Ontario Farms by Revenue Class, 1997 ............ 188
Total Number of Livestock Farms by Region ................... 189
Livestock Units and Top-ten Counties/Municipalities
in Terms of Manure Production, 1996 ............................. 192
Livestock Units and Manure Production by Township,
1996 ................................................................................ 195
Nitrogen, Phosphorus, and Potassium Levels Excreted
in Manure in 1986 and 1996 in the Top-ten Counties/
Municipalities (in million kg/yr) ...................................... 199
Nitrogen, Phosphorus, and Potassium Excreted in
Manure in 1986 and 1996, at the Township Level
(in thousand kg/yr) .......................................................... 201
Livestock Farms and Manure Production by Region ........ 202
Tillable Land and Amount of Land under Liquid Manure
and Solid Manure Applications (as % of tillable hectares)
in Six Counties/Municipalities in Ontario† ...................... 203
Forecasted Livestock Units and Manure Production:
Swine ............................................................................... 219
Forecasted Livestock Units and Manure Production:
Cattle ............................................................................... 219
Forecasted Livestock Units and Manure Production:
Poultry ............................................................................. 219
A Comparison of Manure Production Forecasts ............... 220
The Management of Manure in Ontario with Respect to Water Quality
xi
Table A4.1.1 Coefficients Used to Calculate Livestock Units for Pigs .... 225
Table A4.1.2 Coefficients Used to Calculate Livestock Units
for Cattle ......................................................................... 225
Table A4.1.3 Coefficients Used to Calculate Livestock Units
for Poultry ....................................................................... 226
Table A4.3.1 Calculation of Manure, Nitrogen, Phosphorus, and
Potassium Production for Pigs .......................................... 228
Table A4.3.2 Calculation of Manure, Nitrogen, Phosphorus, and
Potassium Production for Cattle ...................................... 229
Table A4.3.3 Calculation of Manure, Nitrogen, Phosphorus, and
Potassium Production for Poultry..................................... 229
Table A4.4.1 Dairy, Beef, Hog, Poultry/Egg, and Livestock
Combination Farms ......................................................... 230
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production
by County/Municipality, in 1986, 1991, and 1996 .......... 231
Table A4.6.1 Total Livestock Units and Manure Produced in Six
Counties/Municipalities and Their Respective Townships,
1986, 1991, 1996 ............................................................ 239
Table A4.7.1 Nitrogen, Phosphorus, and Potassium Production in
Ontario Counties/Municipalities, 1986, 1991, 1996 ....... 254
Table A4.7.2 Nitrogen, Phosphorus, and Potassium Produced per Year,
Six Counties/Municipalities ............................................. 256
Table A4.8.1 Livestock Numbers per Tillable Hectare and Manure
Application Method as a % of Tillable Land, 1996 .......... 259
Table A4.9.1 Livestock Numbers, Livestock Units, and Manure
Production Predictions for Swine ..................................... 261
Table A4.9.2 Livestock Numbers, Livestock Units, and Manure
Production Predictions for Cattle ..................................... 261
Table A4.9.3 Livestock Numbers, Livestock Units, and Manure
Production Predictions for Poultry ................................... 262
Table A4.9.4 Total Manure Production (millions L/yr) ......................... 262
xii
Walkerton Inquiry Commissioned Paper 6
Figures
Figure 1-1
Figure 1-2
Figure 3-1
Figure 3-2
Figure 3-3
Figure 3-4
Figure 3-5
Figure 3-6
Figure 3-7
Figure 3-8
Figure 4-1
Figure 4-2
Figure 4-3
Figure 4-4
Figure 4-5
Figure 4-6
Schematic Diagram of the Hydrological (Water) Cycle ........ 6
Schematic Diagram of the Sources and Movement of
Contaminants from Manure to Water Resources .................. 8
The Main Parts of a Manure Management System that are
Relevant to Environmental Contamination by Manure
Constituents ...................................................................... 84
Model to Predict N- and P-output in Pig Manure from
the Feed Input and That Used for Pig Growth ................... 88
Probability that Cows and Calves Will Void Urine or
Feces into a Stream ............................................................ 95
Survival of E. coli O157:H7 in Soils of Different
Texture ............................................................................. 148
Presence of Fecal Coliforms in Test Wells ......................... 154
Partitioning of Precipitation into Surface Runoff and
Drainage after the Application of Liquid Swine or Solid
Beef Manure .................................................................... 158
Evidence for Preferential Movement of E. coli Bacteria
from Manure Applied to a Column of Clay-loam Soil ..... 164
Variation in the Depth of Soil Required to Filter Bacteria
in Manure ........................................................................ 178
Historical Inventory of Cattle, Pigs, and Poultry in
Ontario from July 1, 1976 to July 1, 2000 ....................... 190
Ontario Beef and Dairy Inventory Values......................... 191
Cattle Inventory Trendline, 1976–2010 ........................... 217
Poultry Inventory Trendline, 1976–2010 ......................... 217
Pig Inventory Trendline, 1976–2010 ............................... 218
Potential Future Manure Production ................................ 221
The Management of Manure in Ontario with Respect to Water Quality
xiii
Maps
Map 4-1
Map 4-2
Map 4-3
Map 4-4
Map 4-5
Map 4-6
Map 4-7
Map 4-8
Map 4-9
Map 4-10
Map 4-11
Total Number of Livestock Farms by County/
Municipality, 1996 ........................................................... 190
Total Number of Livestock Units by County/
Municipality, 1996 ........................................................... 194
Total Manure Production by County/Municipality,
1996 ................................................................................ 196
Huron County: Livestock Units by Township, 1996 ........ 196
Huron County: Manure Production (000 L/yr) by
Township, 1996 ............................................................... 197
Niagara Region: Livestock Units by Township, 1996........ 197
Niagara Region: Manure Production (000 L/yr) by
Township, 1996 ............................................................... 198
Total Nitrogen by County/Municipality, 1996 ................. 200
Total Phosphorus by County/Municipality, 1996 ............. 200
Total Tillable Land by County/Municipality, 1996 .......... 202
Percent of Tillable Land Receiving Liquid Manure,
1996 ................................................................................ 205
The Management of Manure in Ontario with Respect to Water Quality
1
1
Introduction
Manure management is a multi-faceted issue. Manure handling practices, water
quality, and livestock concentrations vary across regions because of different
biophysical, economic, and demographic factors. Biophysical factors influence
the nature and properties of manure and its components as they impact on water
quality. Social and economic factors influence the benefits and costs that flow
from animal agriculture and water quality impairment. Regulatory policy must
address both biophysical and social economic aspects as it attempts to minimize
the impact of animal agriculture on rural residents and the environment. The
biophysical, social, and economic factors combine to determine where animal
agriculture can flourish, and hence where and how much manure will be produced.
Prepared for the Walkerton Inquiry, this document is an issue paper describing
basic information on manure production and handling as it affects water quality
in selected jurisdictions. The information is presented within an analytical
framework that encompasses the social and economic considerations which
govern regulatory policy.
Objectives
The objectives of this document are:
•
To describe regulatory policy for manure management in Ontario relative
to other jurisdictions, and to explain why different policy instruments
exist to achieve similar goals.
•
To describe what is known about the potential for contamination of water
resources from manure production and handling, and to consider effects
of various livestock feeding, nutrient transport, and cropping practices.
•
To describe the distribution of animal agriculture in Ontario and associated
manure production with an emphasis on trends over the next ten years.
Within the second objective, we indicate where information is still needed to
protect water resources while allowing efficient agricultural production to
continue on Ontario farms.
This paper has been prepared for discussion purposes only and does not represent the findings or
recommendations of the Commissioner.
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Walkerton Inquiry Commissioned Paper 6
Procedures
We reviewed the literature on regulatory mechanisms governing the protection
of water quality and public health. The literature was selected to cover those
public documents that describe policies, laws, regulations, and programs as
they pertain to livestock waste and water. Information was selected to exclude
impacts on water resources by agricultural contaminants that do not originate
in livestock waste. In addition, documents that describe strategies and
approaches for the selection of regulatory mechanisms were also included.
Documents available to the public in electronic form through government
sources were also considered.
Included in this report are regulatory policies governing manure management
for water protection in jurisdictions including Quebec, New Brunswick,
Ontario, New York State, Kentucky, and some European Union countries with
a focus on the Netherlands. No attempt is made to evaluate these approaches.
It is important to remember that what works well in one jurisdiction may not
work at all in another. The reader is encouraged to keep in mind that the more
strict regulatory approaches are not necessarily the most effective from the
perspective of achieving set water quality goals at least cost to society. Similarly,
what appear to be the least expensive approaches from a regulatory standpoint
might actually be the most expensive from society’s standpoint, if they are very
inefficient at achieving water quality goals.
We also reviewed the literature on the biophysical aspects of manure handling,
together with that on the presence of microbial pathogens and natural hormones
in animal manure. We selected information that contributed to the
understanding of those processes taking place during manure handling that
affected the potential loading of contaminants at any time. Further selection
focused only on aspects related to the potential for the contamination of drinking
water. To meet the necessary time-lines, the depth of this review varied
depending on the current information pertinent to Ontario. Original material
has been included to provide clarification on factors affecting the potential for
surface and groundwater contamination by materials from manure.
In evaluating manure production in Ontario, the focus has been on swine,
dairy, beef, and all poultry enterprises. We developed estimates at the township
level and aggregated them to the county and provincial scales. Forward
projection has involved consultation with industry as well as evaluating the
future demand for meat and animal products.
The Management of Manure in Ontario with Respect to Water Quality
3
Background
As world demand for animal protein continues to increase, so too do the
problems associated with handling manure, the byproduct of the livestock
industry. The potential for environmental contamination from the large volumes
of manure produced has been a major concern, and became a reality for the
residents of Walkerton, Ontario, in May 2000.1
The issue for Walkerton residents was contamination of groundwater, which
was used as a source of drinking water, with the bacterial pathogens Escherichia
coli O157:H7, which causes hemorrhagic colitis and (in some patients) can
result in hemolytic-uremic syndrome, and Campylobacter jejuni. In addition to
pathogens, the water regularly showed elevated levels of nitrate.
Section 2 of this paper presents a thorough review of the regulations, policies,
and management guidelines governing manure management and water
protection. The goals of environmental regulations are:
•
to provide private decision makers (whose actions contribute to water
quality impairment) with the incentives necessary to consider the full
cost of their production activities and
•
to achieve specific water quality goals at the least cost to society, including
producers and regulators.
Regulatory instruments include voluntary or non-voluntary, command-andcontrol or market-based approaches, design-based or performance-based
instruments, and those that aim to distinguish between regulatory differences
(point source or non-point source). Environmental regulations vary dramatically
between regions. Those with more severe problems would be more likely to
implement stricter, more expensive regulations, while regions with relatively
minor problems might rely on less costly voluntary measures. However, most
regions are introducing new, more stringent policy instruments.
1
M.H. Miller, 1991, “Environmental considerations in land application of animal manure-water
pollution,” Proceedings of the National Workshop on Land Application of Animal Manure, CARC,
Ottawa, Ontario, June 11–12, p. 125; M.H. Miller, T.C. Martin, E.G. Beauchamp, R.G.
Kachanoski, and H.R. Whiteley, 1990, Impacts of Livestock Manure on Water Quality in Ontario:
An Appraisal of Current Knowledge (Guelph, ON: Centre for Soil and Water Conservation).
4
Walkerton Inquiry Commissioned Paper 6
Regulatory Instrument
•
•
•
•
Command and Control
Laws (legislative acts and zoning)
Standards (setbacks, public health rules/guidelines
Permits (by-laws, building permits)
Mandatory manure handling practices
Description
• create a legally enforceable environment in which
producers are expected to comply or face
consequences of non-compliance
• attempts to influence producer decisions on the use
Market Instruments
of production inputs that are correlated to potential
• Design-based (includes subsidies, low-interest loans,
water quality impairment.
cost-sharing agreements, taxes, tradeable permits,
• attempts to influence producer behaviour by the
manure rights, and quotas)
use of economic charges and subsidies indexed to
• Performance-based (includes charges and subsidies,
regional ambient levels of pollutants.
liability rules
• creating and fostering markets for manure and
• Contracts, leases, and transferring manure rights
treatment
•
•
•
•
Voluntary
Best management practices
Education
Certification
Farm plans
• any measure a producer may chose to participate
in with no repercussion for non-compliance and no
final incentives for compliance
• regulation without education is less effective than a
combined approach.
Successful policies are well-integrated combinations of individual components.
Factors that determine the best mix of policies for any given area include:
•
•
•
•
•
•
•
•
existing legislation and levels of government responsibility,
the severity of existing water quality problems,
costs imposed on society,
costs of monitoring and enforcement,
costs of providing necessary incentives for voluntary programs,
watershed-specific geological features,
costs to farmers for altering practices, and
expectations of long-term industry trends.
In the late 1990s, a review of the state of U.S. water bodies estimated that onethird of all surface water continues to be affected by some degree of impairment.
Surface runoff is now the most significant factor affecting water quality, and
agriculture is the largest contributor to water pollution caused by runoff.
Regulations aimed at reducing agricultural runoff would deliver a greater
response at less cost than regulations aimed at industries causing point source
water quality problems.
Section 3 presents an intensive review of the biophysical aspects of manure
management in Ontario. Farm manure is a potentially valuable source of
The Management of Manure in Ontario with Respect to Water Quality
5
nitrogen, phosphorus, potassium, and other inorganic nutrients for plants.
Organic carbon compounds in manure can be transformed by microbial activity
into materials that are effective binding agents in the soil. Organic compounds
in manure also enter the nutrient cycles within the soil in which nutrients are
mineralized into forms that are readily available to plants. The sustainable use
of resources requires that the most effective use be made of animal manure to
enhance soil structure and productivity.2
But manure can cause contamination of groundwater. Potential contaminants
include pathogenic microorganisms; nitrogen; phosphorus, which can cause
eutrophication of fresh water; dissolved organic carbon, which contributes
to turbidity in water; endocrine-disrupting compounds; and metals such as
copper. Turbidity appears to be important for the survival of some pathogens
in water supplies.3
Identifying the risk of environmental contamination from manure is complex.
It is impossible to predict precisely what will happen to manure under any
given set of conditions. Many factors impact the fate of manure constituents:
•
the nature of manure itself, which varies considerably depending on the
type, diet, and age of the livestock; the type of livestock housing and use
of bedding; type and length of manure storage; and the method, timing,
and rate of manure application on fields;
•
the characteristics of the land receiving the manure, including soil texture,
slope, depth to water table, proximity to water resources, and tillage; and
2
H. Kirchmann and E. Witter, 1992, “Composition of fresh, aerobic and anaerobic farm animal
dungs,” Bioresource Technology, 40, p. 137; A. Krogdahl and B. Dahlsgard, 1981, “Estimation of
nitrogen digestibility in poultry: Content and distribution of major urinary nitrogen compounds
in excreta,” Poultry Science, 60, p. 2480; L.E. Lanyon and D.B. Beegle, 1989, “The role of on-farm
nutrient balance assessments in an integrated approach to nutrient management,” Journal of Soil
and Water Conservation, 44, p. 164; N.K. Patni and P. Y. Jui, 1987, “Changes in solids and carbon
content of dairy-cattle slurry in farm tanks,” Biological Wastes, 20, p. 11; F.J. Stevenson, 1982,
“Origin and distribution of nitrogen in soil,” Nitrogen in Agricultural Soils (Madison, WI: American
Society of Agronomy); A. Wild, 1988, “Plant nutrients in soil: Nitrogen,” Russell’s Soil Conditions
and Plant Growth, 11th ed. (New York: Wiley), p. 652; J.C. Zubriski and D.C. Zimmerman,
1974, “Effects of nitrogen, phosphorus, and plant density on sunflower,” Agronomy Journal, 66, p. 798.
3
J. Aramini, M. McLean, J. Wilson, J. Holt, R. Copes, B. Allen, and W. Sears, 2000, Drinking Water
Quality and Health Care Utilization for Gastrointestinal Illness in Greater Vancouver, <www.hc-sc.gc.ca/
ehp/ehd/catalogue/bch_pubs/vancouver_dwq.htm>.
6
Walkerton Inquiry Commissioned Paper 6
•
the weather (e.g., wind speed during application and rainfall intensity,
frequency, and duration before and after manure application), which
determines if potential contaminants move off-site in surface runoff, tile
drainage flow, groundwater, or air or remain in the rooting zone where
nutrients can be taken up by crops.
Two major water resources are recognized as sources of drinking water:
•
surface water, which includes streams, municipal drains, rivers and lakes
and
•
groundwater, which consists of saturated zones in various strata of subsoil
and rock.
The water or hydrological cycle (figure 1-1) is a major driver in determining
the movement of contaminants. It affects the distribution of contaminants in
the surface and groundwater as well as losses in gaseous form. The main
components of the hydrological cycle are precipitation, evapotranspiration,
Figure 1-1 Schematic Diagram of the Hydrological (Water) Cycle
Evapotranspiration
Runoff
Unsaturated Zone
Tile drain
Water table
Infiltration
Saturated Zone
Ground water flow
by overland flow
The Management of Manure in Ontario with Respect to Water Quality
7
drainage, and runoff. The thirty-year average annual values for these components
have been estimated for three sites in Southern Ontario (Harrow, Guelph, and
Ottawa) and Kapuskasing in Northern Ontario (table 1-1).
Evapotranspiration, drainage, and runoff represent the fate of the precipitation
component of the cycle. Averaged across the four Ontario sites,
evapotranspiration accounted for 64% of precipitation, drainage 23%, and
runoff 12%. Some of the drainage water moves laterally in the near-surface
layer of the soil (interflow) and then to streams. Where tile drains are present,
some proportion of drainage enters the drains and is consequently emitted to
surface water instead of recharging groundwater.
Contaminants from manure can enter surface water bodies in the surface runoff
from fields and yards, in interflow, in discharge from tile drains, and in
groundwater. Contaminants enter groundwater by direct transport through
rock and overlying soil or through man-made ducts such as abandoned,
improperly sealed, or poorly maintained wells. In the process called leaching,
materials are dissolved from the soil or rock as the water moves through.
Runoff in this document is restricted to mean surface runoff, but other authors
have included interflow and discharge from tile drains as part of the runoff
from agricultural land. Strictly speaking, surface runoff and direct entry into
wells do not contain soil leachate, although some leaching will occur as rain or
Table 1-1 Annual Water Balance Components (mm) at Four Sites in
Ontario for the Period 1961 to 1990 (average ± standard
deviation)
Harrow
Guelph
Ottawa
Kapuskasing
Precipitation
902±138
863±126
871±117
860±131
Evapotranspiration
675±68
74%
497±50
58%
562±38
64%
505±37
59%
Drainage
163±90
18% †
283±108
33%
201±137
23%
153±85
18%
Runoff
46±56
5%
81±64
9%
100±74
11%
206±53
24%
† Evapotranspiration, deep drainage, and runoff are also given as a percentage of precipitation.
Source: G.W. Parkin, C. Wagner-Riddle, D.J. Fallow, and D.M. Brown, 1999, “Estimated seasonal and annual water
surplus in Ontario,” Canadian Water Resources Journal, 24(4), p. 277.
8
Walkerton Inquiry Commissioned Paper 6
meltwater moves to a surface or groundwater source via the other routes. Both
surface and groundwater can therefore be impacted by runoff that picks up
contaminants on the surface of the soil or on yards, as well as from manure
that has been incorporated into shallow soil layers.
The ways in which potential contaminants can be lost from manure or made
immobile greatly influence the likelihood that a given water resource may
become affected. This is summarized in figure 1-2.
To assess the potential impact of manure on water quality, it is important to
recognize the possibility for changes in the contaminant content at different
stages of the management system. Pathogens may not survive a period of storage
or the concentration of some nutrients may diminish. Nitrogen in manure is
generally present in organic and inorganic forms. The main inorganic form is the
ammonium ion, which can be transformed into ammonia and released as a gas
or converted to nitrate (NO–3) with nitrite as an intermediate. Nitrite and nitrate
Figure 1-2 Schematic Diagram of the Sources and Movement of
Contaminants from Manure to Water Resources
Point
source
Point source
e.g., Barnyard
e.g., Barnyard
Storage
Storage
Diffuse
source
Diffuse source
Surface Runoff
Surface
runoff
e.g., Field:
e.g., Field:
Manure
application
Manure application
Grazing
Grazing
Surface
Surface
water
water
Infiltration
Infiltration
Infiltration
Infiltration
Drain
Drain
tile
tile
Ground
water
Groundwater
The Management of Manure in Ontario with Respect to Water Quality
9
are of concern in potable water because of methemoglobinemia. Bacteria at the
back of the tongue, or if present in the stomach, convert nitrate to nitrite. When
nitrite enters the blood stream, it reacts with hemoglobin to form methemoglobin,
which is incapable of releasing the bound oxygen for use in other tissues. This
irreversible binding of oxygen to methemoglobin results in a cyanosis, which
mainly affects newborn infants.4 Such infants do not secrete sufficient acid into
the stomach to give the pH of about 2 (high acidity) found in older people.
Agricultural land, particularly if it is under row crops or is used for intensive
animal production, is often associated with groundwater having NO3–
concentrations near or above 10 mg N/L.5 In contrast, the upper limit of
NO3– concentrations in groundwater not influenced by anthropogenic activity
is considered to be 3 mg N/L.6
Gaseous losses of nitrogen lead to enhanced concentrations of ammonia and
oxides of nitrogen in the atmosphere.7 Ammonia release to the atmosphere has
importance because it subsequently contributes to acidification of soils. Nitrous
oxide (N2O) is a potent greenhouse gas. Both gases are soluble in water.
Ammonia can be returned in precipitation and, together with NO2 (nitrogen
dioxide), in dry deposition, thus adding to the soil mineral nitrogen fraction
in an uncontrolled manner. Release of ammonia into the atmosphere through
volatilization of fertilizer nitrogen and animal wastes is almost entirely due to
agricultural activities. Ammonia is not a greenhouse gas. It is, however, of
concern since releases of ammonia to the atmosphere have both local and long4
P. Fraser and C. Chilvers, 1981, “Health aspects of nitrate in drinking water,” The Science of the
Total Environment, 18, p. 103; R. Rajagopal and G. Tobin, 1989, “Expert opinion and groundwater quality protection: The case of nitrate in drinking water,” Ground Water, 27, p. 835; A.P.S.
Terblanche, 1991, “Health hazards of nitrate in drinking water,” Water SA, 17, p. 77.
5
M.J. Goss, D.A.J. Barry, and D.L. Rudolph, 1998, “Groundwater contamination in Ontario farm
wells and its association with agriculture: 1. Results from drinking water wells,” Journal of Contaminant
Hydrology, 32, p. 267; J.D. Toth and R.H. Fox, 1998, “Nitrate losses from a core-alfalfa rotation: Lysimeter
measurement of nitrate leaching,” Journal of Environmental Quality, 27, p. 1027.
6
R.J. Madison and J.O. Brunett, 1985, “Overview of the occurrence of nitrate in groundwater of
the United States,” National Water Summary 1984, USGS Water Supply Paper No. 2275
(Washington, D.C.: U.S. Govt. Printing Office), p. 93.
7
C.B. Kresge and D.P. Satchell, 1960, “Gaseous loss of ammonia from nitrogen fertilizers applied
to soils,” Agronomy Journal, 52, p. 104; J.W. McGarity and J.A. Rajoratham, 1972, “Apparatus for
the measurement of losses of nitrogen as gas from the field and simulated field environments,” Soil
Biology & Biochemistry, 4, p. 1; J.A. Ryan and D.R. Keeney, 1975, “Ammonia volatilization from
surface applied sewage sludge,” Journal (Water Pollution Control Federation), 47, p. 386; J.A. Ryan,
D.R. Keeney, and L.M. Walsh, 1973, “Nitrogen transformations and availability of an anaerobically
digested sewage sludge in soil,” Journal of Environmental Quality, 2, p. 489.
10
Walkerton Inquiry Commissioned Paper 6
range effects. Locally, impingement with crops and other vegetation may give
rise to foliar damage. At longer range, ammonia deposition gives rise to nitrogen
inputs with eutrophication effects on sensitive ecosystems.8 Ammonia also plays
an important role in the atmospheric chemistry of sulphur dioxide as it increases
the loading rate of SO2 in cloud water droplets, thereby contributing to
acidification of soils and surface waters.9 Ammonia is also involved in reactions
with other pollutants, such as oxides of nitrogen (NOx), in the atmosphere.
Ammonia dissolved in surface runoff from yards or manure stores can enter
surface water and negatively impact aquatic life.
Phosphorus in manure does not pose a direct threat to humans. However,
when it enters freshwater bodies it enriches them, making them more productive
– a process known as eutrophication. The effect is to increase the growth of
algae within the habitat. The death of these algae and their breakdown by
microorganisms can greatly deplete the oxygen concentration in the water so
that the animal population is subject to oxygen deprivation. In extreme
conditions fish can be asphyxiated.10 Blue-green algae (cyanobacteria) grow
rapidly in the presence of phosphorus. Some of these organisms produce toxins
that can cause illness in humans. Although it is unlikely that drinking water
containing the toxins would result in acute illness, long-term exposure may be
associated with the development of cancer.11
Some metals, such as copper (Cu) and zinc (Zn), are used to promote growth
in animals, but their concentration in drinking water is restricted mainly for
aesthetic reasons.
Although metals and nutrients such as phosphorus are not lost from manure in
gaseous form, the breakdown of organic carbon compounds during storage can
greatly decrease the dry matter content of the manure. Hence, the final
concentration of contaminants per unit weight of dry matter can be much greater
8
M.A. Sutton, C.J. Place, M. Eager, D. Fowler, and R.I. Smith, 1995, “Assessment of the magnitude
of ammonia emissions in the United Kingdom,” Atmospheric Environment, 29, p. 1393.
9
H.M. ApSimon, M. Kruse, and J.N.B. Bell, 1987, “Ammonia emissions and their role in acid
deposition,” Atmospheric Environment, 21, p. 1939.
10
P.A. Chambers, M. Guy, E.S. Roberts, M.N. Charlton, R. Kent, C. Gagnon, G. Grove, and N.
Foster, 2001, Nutrients and their Impact on the Canadian Environment (Ottawa: Agriculture and
Agri-Food Canada, Environment Canada, Fisheries and Oceans Canada, Health Canada, Natural
Resources Canada, Public Works, and Government Services Canada), p. 233.
11
W.W. Carmichael, 1994, “The toxins of cyanobacteria,” Scientific American, January, p. 78; I.R.
Falconer, 1991, “Tumor promotion and liver injury caused by oral consumption of Cyanobacteria,”
Environmental Toxicology and Water Quality, 6, p. 177.
The Management of Manure in Ontario with Respect to Water Quality
11
when manure is applied to land than it was at the time of excretion. Manure
treatment by composting has a similar result. Appropriate application rates may
therefore need to be relatively small, less than equipment can deliver reliably.
Fecal coliform, streptococci, and sometimes salmonella are the main pathogenic
bacteria of concern. Important protozoan pathogens include Cryptosporidium
and Giardia. The more animals on a farm, the greater the likelihood of pathogens
in the manure. The survival of non-indigenous bacteria following land
application of manure depends on soil pH, soil water content, organic matter
content, soil texture, temperature, availability of nutrients, adsorption properties
of the soil, and biological interactions in the soil (earthworms can reduce bacteria
populations). Populations of microorganisms are dynamic – they are influenced
by factors that affect their survival. Many are also motile.
Farm animals also excrete natural hormones, such as estrogen and progesterone,
which are known to affect human development through interference with
endogenous production and action. Hormone implants are also used to increase
growth rates, and the metabolic breakdown products are also excreted.
Antibiotics are applied to treat disease, but may also be given prophylactically
in feed. These compounds can also be excreted, but little has been written
about their transfer to water resources.
Of the 229 listed spills recorded by the Southwestern Region of the Ontario
Ministry of the Environment, 17% were attributed to problems with manure
storage. Where storages hold less than 180 days worth of manure production,
manure is often spread on partly frozen ground, which risks endangering surface
water supplies. Manure storages themselves, either earthen or concrete, in areas
with shallow bedrock, pervious soils, or shallow water tables, can endanger
water supplies. However, as long as Ontario guidelines for construction are
followed, the self-sealing nature of manure can prevent major contamination
from small cracks. Problems can become acute, however, if the leak intercepts
an unsealed tile drain. Manure can then move directly to a water course. If
leaks have occurred, the time of major concern is when the structures are
decommissioned. The water in stored manure will help maintain saturated
conditions in the soil near the point of the leak. As the soil dries after storage
stops, ammoniacal nitrogen can be nitrified and organic nitrogen mineralized,
resulting in nitrate that can then move to the groundwater.
The movement of liquid manure to tile lines is the most frequently reported
type of manure spill. Researchers have documented the movement of liquid
12
Walkerton Inquiry Commissioned Paper 6
manure to tile lines through macropore or preferential flow. In this process,
water and its constituents move by preferred pathways through a porous
medium. It means that part of the matrix is effectively bypassed, as flow
occurs through large pores and channels in the soil created by earthworms,
roots, freeze-thaw, and cracking. Macropores have been shown to allow
manure liquids to move to subsurface drains within an hour of application.
One study showed that as a result of preferential flow, 96% of the infiltrating
water moved through only 0.32% of the soil volume. Preferential flow occurs
when rainfall or the liquid application rate exceeds the infiltration rate of the
soil or when the soil is already saturated at the time of the rainfall or
application. Flow through the larger macropores occurs much more quickly
than through smaller pores.
Pre-tillage (tilling the land prior to manure application) has been shown to
limit macropore flow by severing the continuous cracks, worm holes, root
channels etc. Pre-tillage tines have been added to injection machinery to
achieve the same effect. Some no-till farmers who want to preserve the
beneficial soil conditions created by continuous no-till systems on their land,
argue that it should be sufficient to till a swath over the tile lines while leaving
the area in between undisturbed. This area needs to be addressed by further
research.
Equipment manufacturers have been working on ways to reduce compaction
caused by large tankers. Compaction can encourage surface runoff of manure,
which may then enter adjacent water courses. Manufacturers have also been
improving the uniformity with which liquid manure is spread. Uniform
distribution is essential if farmers are to rely solely on the nutrients contained
in manure for their crop’s nutrient needs.
In addition to the choice of application method, producers also have to make
decisions on the timing of their land application. Factors to consider include
the risks from soil compaction, likelihood of runoff, and nutrient loss though
ammonia volatilization. The timing of manure applications is critical for the
availability of nitrogen both to crops and on the potential for environmental
impacts. As manure storage on many farms is limited, the common periods for
application are the fall, winter, and spring. In spring, applications may be as a
pre-plant fertilization or as a side- or top-dressing. The experimental evidence
shows that compared with spring applications, manuring land in fall or winter
results in lower recovery of applied nitrogen by the crops, greater risk of leaching
and denitrification, and longer survival of bacteria.
The Management of Manure in Ontario with Respect to Water Quality
13
Although it is impossible to accurately predict the fate of manure constituents
following land application of manure, the development and use of agricultural
best management practices minimize the risk of environmental contamination.
Significant research is needed in the field of manure management if water
resources are to be protected from contaminants originating in manure. Both
basic and applied research is required as well as machinery development. These
needs cover aspects of:
•
•
•
•
feeding regimes
animal husbandry
manure treatment
field application
Section 4 provides an overview of manure production in Ontario in terms of
distribution, volume, and spreading practices. Statistics Canada census data
and livestock inventory numbers show current manure production levels. Future
industry growth and manure management technologies are discussed.
About 67% of Ontario’s agricultural sales comes from 20% of its farms, i.e.,
farms with annual gross revenue greater than $250,000. The majority of Ontario’s
livestock farms are located in the OMAFRA’s Southern and Western regions.
Based on 1996 estimates, cattle produced 63% of the manure, swine 31%, and
poultry 6%. Estimated manure production for the whole province declined by
7.5% between 1986 and 1996. Poultry manure production increased by 13.8%
while cattle and swine decreased by 8.3% and 9.3% respectively. Manure
production is projected to drop by 12% by 2010.
Based on 1996 census data, the top five counties in terms of manure production
are Perth, Huron, Wellington, Oxford, and Bruce. Provincially, 19% of the tillable
land receives manure. Even in Perth County, which has a relatively high livestock
concentration, only 30% of the tillable land receives manure. If all of Ontario’s
agricultural land could receive equal amounts of manure, Ontario could support a
much larger livestock industry. However, given current manure technologies and
its current economic value, it is not feasible to transport manure over long distances.
Section 4 discusses how to balance society’s need for safe, high-quality potable
water with the needs of livestock farms to remain competitive and not be unduly
burdened with extensive regulations.
14
Walkerton Inquiry Commissioned Paper 6
2
Regulations, Policies, and Management Guidelines
Governing Manure Management and Water Protection
2.1 Introduction
This section provides a comparative summary of the regulations governing
manure management for water protection. The scope includes Quebec, New
Brunswick, Ontario, New York State, Kentucky, and some European Union
countries with a focus on the Netherlands. These jurisdictions were selected
because they have similar geographical features to those of Ontario, similar
legal and institutional frameworks, or a variety of regulatory devices that have
been recently developed to take into account specific challenges associated with
manure management and water protection.
Market forces, technological changes, and industry restructuring continue
to cause significant changes in the livestock industry. One result of these
changes is a trend toward a concentration of livestock and poultry production
in all the major livestock producing nations, and a commensurate geographic
concentration of livestock waste products. Concerns about environmental
impacts have arisen in most of the affected countries, especially in areas where
the environmental capacity to absorb the additional nutrients is limited.12
Accordingly, most livestock-producing jurisdictions have developed and
enacted new policies to control environmental impacts. While many of the
new policies rely, in part, on pre-existing regulatory mechanisms, there is a
clear and growing trend towards evaluating policy needs to specifically target
livestock waste management. The published literature includes several studies
that compare the efficacy of various policy instruments with regard to features
such as impact on pollution levels, costs of implementation, effect on the
industry, and institutional requirements for successful implementation. Policy
mechanisms have also been compared across different industries and water
impairment sources.
From examining the research and practices in this area, one can conclude that:
•
•
a successful policy is made up of a well-integrated combination of
individual components,
no one policy is optimal for all situations, and
12
U.S. General Accounting Office (USGAO), 1999, Animal Agriculture: Waste Management Practices,
(Washington, D.C.).
The Management of Manure in Ontario with Respect to Water Quality
•
15
a specific component that works well in one context may be inadequate
in another.
Jurisdictions vary in how the different levels of government interact. The level
and type of authority exercised by each level of government differs when dealing
with the severity of water impairment problems. Differences across regions
also exist in other factors, such as geological and physical features, the costs of
complying with a given standard or practice, demographics, and other social
and economic activities that may mitigate or exacerbate water quality issues
associated with animal agriculture.
Section 2 is divided into several subsections. The goals of regulatory policy, in
the context of livestock waste management are discussed in section 2.2 which
also considers a number of reasons why policies and regulatory mechanisms
that are targeted to similar goals can exhibit such a variety of differences. Results
of studies that analyze differences between policy approaches are summarized.
Several examples illustrate basic points, but details of these examples are left
for later subsections that describe specific policies used in the various
jurisdictions.
The jurisdictional reviews start with the United States (section 2.3), which has
seen several new initiatives to regulate animal waste impacts on water in the
last five years alone. Development of these initiatives has been coordinated
among the different branches of government and levels of government, including
the U.S. Environmental Protection Agency (USEPA) and the Department of
Agriculture (USDA). Such coordinated and integrated efforts have not yet
been seen to the same scale in Ontario.
Section 2.4 discusses regulations in selected jurisdictions in Europe, where the
European Union (EU) helps to play an integrating role. European policies in
general are more stringent than those in Canada and the United States, in part
because the severity of existing water quality problems is greater. It means that
to meet similar ambient nutrient standards, many European nations have to
make bigger improvements, and that the waste per animal unit can create greater
environmental stress than is the case in North America. European policies are
especially interesting in that they tend to rely on a combination of marketoriented regulatory mechanisms.
Section 2.5 reviews the approaches of New Brunswick (which has a relatively
new set of policies), Quebec, and Ontario. Ontario is considered last so that
16
Walkerton Inquiry Commissioned Paper 6
there is a context for the reader to consider the existing approach in this province
relative to potential alternatives. Ontario has yet to see implementation of new
regulations that specifically target livestock waste management for water resource
protection. The Ontario Ministry of Agriculture, Food and Rural Affairs
(OMAFRA) recently initiated a process to review existing policies. The Ontario
subsection concludes with a list of existing best management practices that are
currently recommended for livestock producers in the province.
2.2 Goals of Regulation and Types of Regulatory Devices
Regulatory approaches vary widely across jurisdictions and, due to the industry
trend toward concentration, have recently undergone significant changes within
jurisdictions. In their assessment of the impacts of regulation on the hog industry
in several European nations and 25 U.S. states, Beghin and Metcalf review
recent trends in new environmental regulations aimed at livestock waste
management.13 Their review emphasizes “the evolving and heterogeneous nature
of environmental regulation, which varies dramatically from state to state and
across countries. Despite the geographical disparity in regulations, there is
everywhere a common trend toward introducing more stringent and new policy
instruments.”14 Table 2-1 illustrates the variety in type and stringency of
regulatory mechanisms across the jurisdictions included in their study.
2.2.1 Goals of Regulation
The conceptual basis of environmental regulation is to provide private decision
makers, whose actions contribute to water quality impairment, with the
incentives necessary to consider the full cost of their production activities. Water
quality impairment can impose costs on all members of society. These costs
include increased municipal water treatment costs, costs of greater risk of illness
caused by changes in water quality, and costs to society from loss of fish and
wildlife habitat. In many cases, producers are unaware of the full extent of
these costs and have little incentive to consider them as they do other production
13
J. Beghin and M. Metcalf, 2000, “Market hogs? An international perspective on environmental
regulation and competitiveness in the hog market,” Choices, First Quarter, p. 28.
14
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
17
Table 2-1 Environmental Stringency Ranking of Environmental
Regulations for the Hog Industry
Jurisdiction Types of Regulatory Instruments Used
Very Restrictive
The Netherlands
MPRs (Manure production rights), ammonia rights, nutrient standards for phosphate
and nitrogen, nutrient management plan, facility design requirements, waste system
approval, setbacks, reduction in MPRs, reduction of output, taxes on excess nutrients,
scheduling and technical restrictions on manure spreading, odor permit.
Denmark
Nutrient standards for nitrogen, restrictions on spreading techniques and scheduling,
facility design and waste system requirements and approval, setbacks, nutrient
management plan, fines on excess nutrient, land cover requirements, land ownership
requirement increasing with farm size, moratorium on farms exceeding 15,000 head.
Georgia
Local regulations, public hearings, geological testing, strict setbacks, facility and waste
system approval, fees, nutrient standards, groundwater monitoring, discharge
requirements exceed EPA criteria.
Kansas
Public hearings, setbacks facility approval, waste system approval, fees, nutrient
standards bonding, groundwater monitoring, discharge requirements, required training.
Maryland
Local regulation, public hearings, geological testing, setbacks, facility and waste system
approval, fees, nutrient standards, bonding, groundwater monitoring, discharge
requirements, required training.
Iowa
Public hearings, geological testing, strict setbacks, facility approval, extensive waste
system approval, fees, nutrient standards, groundwater monitoring, discharge
requirements exceed EPA criteria, required training.
South Carolina
Public hearings, geological testing, strict setbacks, approval for facility, extensive waste
system approval, fees, nutrient standards, groundwater monitoring, discharge
requirements exceed EPA criteria, required training.
South Dakota
Local regulation, public hearings, geological testing, setbacks, facility and waste system
approval, fees, nutrient standards, groundwater monitoring, discharge requirements
exceed EPA criteria, required training.
Restrictive
Belgium
Nutrient standards for nitrogen and phosphate, facility and waste system approval,
manure shipping for non-family farms, restrictions on manure spreading techniques and
scheduling, nutrient management plan, taxes on excess nutrient.
Arkansas
Public hearings, geological testing, setbacks, facility and waste system approval, fees,
nutrient standards, discharge requirements exceed EPA criteria, required training,
moratorium.
PPublic
ublic hearings,
hearings,geological
geologicaltesting,
testingsetbacks,
, setbackswaste
, wastsystem
e systeapproval,
m approvfees,
al, fenutrient
es, nutristandards,
ent
sbonding,
tandards,groundwater
bonding, gromonitoring,
undswater mdischarge
onitoring, requirements
discharge requexceed
iremenfederal
ts exceeEPA
d fedcriteria,
eral
Erequired
PA critertraining.
ia, required training.
Illinois
Indiana
Local regulation, geological testing, setbacks, facility and waste system approval, fees,
nutrient standards, discharge requirements.
Kentucky
Geological testing, setbacks, facility and waste system approval, fees, nutrient standards,
discharge requirements, moratorium.
18
Walkerton Inquiry Commissioned Paper 6
Table 2-1 Environmental Stringency Ranking of Environmental
Regulations for the Hog Industry, cont’d.
Jurisdiction Types of Regulatory Instruments Used
Restrictive (continued)
Minnesota
Local regulation, geological testing, setbacks, facility and waste system approval, nutrient
standards, groundwater monitoring, discharge requirements, moratorium.
Mississippi
Local regulation, public hearings, geological testing, setbacks, facility and waste system
approval, nutrient standards, discharge requirements, moratorium.
Missouri
Local regulation, public hearings, geological testing, setbacks, facility and waste system
approval, fees, nutrient standards, bonding, groundwater monitoring, discharge
requirements, required training.
North Carolina
Local regulation, public hearings, setbacks, facility and waste system approval, fees,
nutrient standards, discharge requirements, required training, moratorium.
Ohio
Public hearings, geological testing, setbacks, facility and waste system approval, fees,
nutrient standards discharge requirements exceed EPA criteria.
Oklahoma
Public hearings, setbacks, facility and waste system approval, fees, nutrient standards,
bonding, groundwater monitoring, discharge requirements exceed EPA criteria, required
training, moratorium.
Oregon
Geological testing, setbacks, facility and waste system approval, fees, nutrient standards,
groundwater monitoring, discharge requirements exceed EPA criteria.
Pennsylvania
Local regulation, geological testing, setbacks, facility and waste system approval, nutrient
standards, groundwater monitoring, discharge requirements exceed EPA criteria,
required training.
Tennessee
Public hearings, geological testing, setbacks, facility and waste system approval, fees,
nutrient standards, discharge requirements, required training.
Virginia
Local regulation, public hearings, facility and waste system approval, fees, nutrient
standards, groundwater monitoring, discharge requirements, required training.
Moderate
Taiwan
Waste system approval and requirements, concentration standards for waste pollution
(BOD, COD, SS), manure spreading prohibited, zoning.
Arizona
Local regulation, geological testing, approval for waste system, nutrient standards,
discharge requirements.
Colorado
Local regulation, setbacks, groundwater monitoring, discharge requirements, local level
moratorium.
Nebraska
Local regulations, public hearings, geological testing, setbacks, facility approval, fees,
nutrient standards, groundwater monitoring, discharge requirements.
Negligible
Poland
New York State
Local regulation, discharge requirements.
Source: Beghin and Metcalf, 2000.
The Management of Manure in Ontario with Respect to Water Quality
19
costs. The role of well-designed regulatory instruments is to make these costs
explicit to the producer, thereby providing the incentive to alter their practices
and reduce potential financial costs. As a result, water quality impairment can
be reduced.
As an ideal, a perfect regulatory instrument would increase the producer’s
marginal cost of water impairment by exactly the marginal cost that is imposed
on society. In this way, the cost of water impairment would be treated as any
other cost of production, and producers would choose practices that result in
optimal levels of water quality for society.15 In reality, it is often not possible
for regulators or producers to determine the exact costs imposed on society as
a result of the activities of a given producer. In addition, regulation imposes
additional costs on society: administrative, monitoring, and enforcement costs.
Therefore, a more realistic goal of environmental policy and regulation is to
achieve specific water quality goals at least cost to society, including producers
and regulators. Much of the economics literature about the environmental
regulation of agriculture assumes this practical goal. The objective of many
empirical studies is to determine least-cost approaches to achieving set
environmental goals.16
The relative severity of regional water quality problems affects the regulatory
goals and the types of regulatory instruments needed to achieve those goals.
The variable of concern is not necessarily the water quality standard that is set,
but the magnitude of the difference between existing quality and the standard,
as well as the costs of achieving incremental improvements. Regions with more
severe problems would be more likely to implement stricter, more expensive
regulations, while regions with relatively minor problems might rely on less
15
Thus, well-designed regulations would not necessarily have zero-impact on water quality as a
goal, but rather would act to strike a balance between society’s costs for food production and the
benefits of improved water quality.
16
R.A. Fleming, B.A. Babcock, and E. Wang, 1998, “Resource or waste? The economics of swine
manure storage and management,” Review of Agricultural Economics, 20, p. 96; R.A. Kramer, W.T.
McSweeny, W.R. Kerns, and R.W. Stavros, 1984, “An evaluation of alternative policies for controlling
agricultural nonpoint source pollution,” Water Resources Bulletin, 20, p. 841; A. Lintner and
A. Weersink, 1996, Evaluating Control Instruments for Improving Water Quality from Multicontaminants in an Agricultural Watershed (Guelph, ON: Department of Agricultural Economics
and Business, University of Guelph); M. Ribaudo, R.D. Horan, and M.E. Smith, 1999, Economics
of Water Quality Protection from Nonpoint Sources: Theory and Practice (USDA/Economic Research
Service, Publication 782); D. Rigby and T. Young, 1996, “European environmental regulations to
reduce water pollution: an analysis of their impact on UK dairy farms,” European Review of
Agricultural Economics, 23, p. 59.
20
Walkerton Inquiry Commissioned Paper 6
costly, voluntary measures. The principal is that the poorer the existing water
quality, the greater the cost to society of an additional unit of waste material.
Therefore, in areas of Europe where water quality is already stressed by activities
of the densely concentrated human population, the waste products of an
additional animal unit impose greater water quality costs than in many regions
of North America, which have yet to experience the same overall levels of stress
to water quality. This trend is also apparent as changes within regions over
time. Thus we see that in the last decade, the industry tended toward increasingly
concentrated livestock facilities, and new regulatory measures, aimed at reducing
the impact of livestock agriculture on water quality, have also increased. The
rates at which different jurisdictions develop new guidelines vary, due to the
change in development of the industry among regions, the physical features of
the watersheds, other human activities that affect regional water quality, and
changes in the uses of local water supplies.
Often, a jurisdiction may have focused heavily on reducing water quality
impairment from specific sources over time. As a result, the additional benefit
to society from increasing stringency of regulation for those sources becomes
quite small relative to increasing the focus on other sources, which had previously
not received the same level of attention. This principal is seen in the United
States where, for the two decades after the Clean Water Act was initially enacted
in 1977, regulators focused on point source pollution from industrial and
municipal effluent. By the late 1980s, a formal review of the state of the nation’s
waters estimated that one-third of all surface water continues to be affected by
some degree of impairment, but that surface runoff was the single most
significant factor affecting water quality.17 Agriculture has generally been
recognized as the largest contributor to water pollution caused by runoff in the
United States.18 Therefore, the costs of regulation aimed at reducing runoff
from agricultural operations would, at the margin, be expected to deliver a
greater response than regulatory actions with similar costs aimed at industries
causing point source water quality problems. It is not surprising, therefore,
that in the last decade important new regulatory and market-based initiatives
17
U.S. General Accounting Office (USGAO), 1999.
Ibid; U.S. Environmental Protection Agency (USEPA), Office of Water, 1999a, B1. Management
Measure for Facility Wastewater and Runoff from Confined Animal Facility Management (Large Units)
[online], [cited: last updated Oct 4, 1999], <www.epa.gov/OWOW/NPS/MMGI/Chapter2/
ch2-2b1.html>; U.S. Environmental Protection Agency (USEPA), Office of Water, 1999b, B2:
Management Measure for Facility Wastewater and Runoff from Confined Animal Facility Management
(Small Units), [online],[cited February 12, 2002], <www.epa.gov/OWOW/NPS/MMGI/Chapter2/
ch2-2b2.html>.
18
The Management of Manure in Ontario with Respect to Water Quality
21
have been developed in the United States to reduce the impacts of livestock
agriculture on water quality.
2.2.2 Types of regulatory instruments
There are a wide variety of regulatory instruments and the various studies use
different criteria to classify them. Criteria include voluntary versus nonvoluntary instruments,19 command-and-control regulation versus market-based
approaches, design-based versus performance-based instruments,20 and those
studies that aim to distinguish between regulatory differences presented by
point source versus non-point source pollution.21 However, underlying most
analytical frameworks is some measure of the incentive necessary for producer
compliance as compared with the level of water quality change achieved and
other regulatory costs.
Existing policy instruments range from those that produce relatively weak
incentive mechanisms, such as education programs that attempt to use moral
suasion to induce producers to voluntarily alter practices, to those with strong
incentive mechanisms, such as issuing permits only after provision of proof
that practices have been altered, levying fines for failure to comply with
recommended practices, and charging fees for increasing livestock holdings.
Policies with weaker incentive mechanisms are often less costly to administer:
monitoring costs may be small or absent, and enforcement costs are, by
definition, lacking entirely. Conversely, stricter regulations incur greater
administrative and monitoring costs and include costly enforcement
mechanisms. Innovations that reduce these associated regulatory costs can alter
the feasibility of different mechanisms.
19
N. Anders Norton, T.T. Phipps, and J.J. Fletcher, 1994, “Role of voluntary programs in agricultural
nonpoint pollution policy,” Contemporary Economic Policy, XII, p. 113; D.J. Bosch, Z.L. Cook, and
K.O. Fuglie, 1995, “Voluntary versus mandatory agricultural policies to protect water quality: Adoption
of nitrogen testing in Nebraska,” Review of Agricultural Economics, 17, p. 13; D.P. Stonehouse, 1996,
“A targeted policy approach to inducing improved rates of conservation compliance in agriculture,”
Canadian Journal of Agricultural Economics, 44, p. 105.
20
A. Conway, 1991, “A role for economic instruments in reconciling agricultural and environmental
policy in accordance with the Polluter Pays Principle,” European Review of Agricultural Economics,
18, p. 467; A. Weersink and J. Livernois, 1996, “Introduction,” in Exploring Alternatives: Potential
Application of Economic Instruments to Address Selected Environmental Problems in Agriculture. Edited
by A. Weersink and J. Livernois (Ottawa: Environment Bureau, Agriculture and Agri-Food Canada).
21
Kramer et al., 1984; M. Ribaudo and R.D. Horan, 1999, “The role of education in nonpoint
source pollution control policy,” Review of Agricultural Economics, 21, p. 331.
22
Walkerton Inquiry Commissioned Paper 6
2.2.2.1 Command-and-control direct regulation
Command-and-control regulations create a legally enforceable environment
wherein producers are expected to comply with a standard practice or face
consequences if they are found to be in non-compliance. Generally, direct
regulation implies that the standard is applied at the individual level and is the
same for all producers, and that monitoring and enforcement are feasible. An
example is the U.S. Clean Water Act, which classifies Concentrated Animal
Feeding Operations (CAFOs) in the same manner as point source industrial
and municipal polluters. Point source polluters are generally held to strict zerotolerance rules and must apply for permit renewal every five years. An exception
is made for CAFOs in the special circumstances of a 25-year 24-hour storm
event, when the owner or operator would not be held liable for water quality
impairment. Otherwise, permits are not granted unless the operation can
produce evidence that its activities do not impair water quality. In this case,
the burden of proof is on the permit applicant, and non-compliance could
result in fines or closure of an operation.22 Because many water quality
impairment problems emanating from livestock waste management are
characterized by its diffuse non-point nature, use of direct regulation is limited
and, as a stand-alone mechanism, is unlikely to achieve regulatory objectives.23
2.2.2.2 Voluntary approaches
Voluntary approaches include educational programs to raise producer awareness
of their impacts on water quality on-farm and off-farm and development of
‘codes of practice,’ which specify combinations of best management practices
(BMPs) that are consistent with reducing water impairment in a given region.
It is generally recognized that the effectiveness of such programs is limited to
those situations in which the recommended practices can achieve water quality
goals without affecting on-farm profit. Given that off-farm impacts on water
quality are generally greater than on-farm impacts, the situations in which
voluntary programs alone would be effective are quite rare.24 Therefore, many
voluntary programs include subsidies to increase the incentives for compliance.25
In this case, the farmers for whom compliance would be least costly are those
most likely to participate. However, these farmers may not be those whose
22
The Clean Water Act, definitions of CAFOs, and terms of permits are discussed later.
Stonehouse, 1996; Ribaudo, Horan, and Smith, 1999; Weersink and Livernois, 1996.
24
Anders Norton, Phipps, and Fletcher, 1994; Ribaudo, Horan, and Smith, 1999.
23
The Management of Manure in Ontario with Respect to Water Quality
23
change in practices would make the largest contribution to water quality
improvement. In other words, resources spent on subsidies might be better
employed otherwise to achieve the same goal. For this reason, Anders Norton
et al. suggest that in cases where water impairment costs are mostly borne offfarm, policy-makers should prefer regulation or other alternatives.26 Bosch et
al. generally concur, but point out that their empirical research indicates that
regulation without education is less effective than a combined approach.27
In situations where the greatest contribution to a local water quality problem is
due to diffuse, non-point source runoff and the water quality costs are not severe,
voluntary approaches are still popular when used in combination with other
mechanisms. However, many approaches that are often classified as ‘voluntary’
actually include positive or negative incentive mechanisms to induce compliance.
For example, in many jurisdictions including Ontario and many U.S. states,
livestock producers who can demonstrate that they have used recommended
codes of practice protect themselves from legal liability in any potential case
where their diligence may have nevertheless resulted in unavoidable water quality
impairment. Protection from liability carries a real value to producers and so
provides an incentive to alter practices and maintain documentation.
In many jurisdictions, voluntary programs include measures that reduce costs to
producers’ for participation and altering practices. These typically consist of tax
breaks and financial assistance to cover some part of those costs. An example is
the USDA’s Environmental Quality Incentives Program (EQIP), specifically
designed to assist producers with the support necessary to alter production
practices.
In all, U.S. federal agencies estimated that they spent $498.7 million, as well as
providing technical assistance to producers for animal waste management during
fiscal years 1996 through 1999.28
Voluntary approaches also include “cross-compliance” mechanisms, which
typically tie a producer’s access to other agricultural support programs to their
participation in conservation programs. In the United States, where crosscompliance had been used for many years, recent trends in agricultural commodity
25
Kramer et al., 1984.
Anders Norton, Phipps, and Fletcher, 1994.
27
Bosch, Cook, and Fuglie, 1995.
28
The EQIP program and others are discussed in more detail later in this chapter; USGAO, 1999.
26
24
Walkerton Inquiry Commissioned Paper 6
income-support programs have weakened incentives to participate in
environmental programs. In addition, uncertainty about the future of farm support
programs due to domestic and international trade policy changes reduces the
economic leverage that cross-compliance programs require. Finally, while farm
income-support programs are diminishing, the importance of environmental
programs to reduce off-farm costs of agriculture is increasing. In general,
agricultural income and commodity policies have different purposes and goals
from environmental regulation, and the economic inefficiencies and policy
problems associated with combining them have brought many researchers to
conclude that the future role of cross-compliance approaches will be limited in
the United States.29
While voluntary approaches are subject to the above limitations, an important
feature of water pollution caused by livestock waste is that much of it comes
from non-point sources. This means that the effect of any given producer’s
actions on the overall level of water quality is not observable either by the
producer or the regulator. The direct impact of a given activity by a given
producer is affected by timing, duration and amount of rainfall, the water
table, slope, proximity to waterways, location in a watershed, and numerous
other geographic and physical variables that are affected by random climatic
events. In many situations, no obvious cause and effect may be apparent between
land-use activities and localized water quality problems. Thus, the best that
one can do is to estimate the probability that a given activity will cause an
impact and estimate the expected costs of the impact on water quality
impairment. The informational problems create tremendous difficulties in
regulatory design.30 A single regulatory rule applied to every producer (perhaps
with systematic and observable differences in producer type) will likely have
different outcomes and be excessively expensive to monitor and enforce.
29
R.E. Heimlich and R. Claassen, 1998, “Agricultural conservation policy at a crossroads,”
Agricultural and Resource Economics Review, 27, p. 95.
30
K. Segerson, 1988, “Uncertainty and incentives for nonpoint pollution control,” Journal of
Environmental Economics and Management, 15, p. 87; K. Segerson, 1990, “Incentive policies for
control of agricultural water pollution,” Agriculture and Water Quality: International Perspectives
(Boulder, CO: Lynne Rienner), p. 39; R. Cabe and J. Herriges, 1992, “The regulation of nonpointsource pollution under imperfect and asymmetric information,” Journal of Environmental Economics
and Management, 22, p. 134; J.B. Braden and K. Segerson, 1993, “Information problems in the
design of nonpoint-source pollution policy,” Theory, Modeling and Experience in the Management
of Nonpoint-source Pollution (Boston: Kluwer Academic), p. 1; J.S. Shortle and D.G. Abler, 1994,
“Incentives for nonpoint pollution control.” Nonpoint Source Pollution Regulation: Issues and Analysis
( Boston: Kluwer Academic), p. 137; Weersink and Livernois, 1996.
The Management of Manure in Ontario with Respect to Water Quality
25
2.2.2.3 Market-based economic instruments
Because of the challenges presented by non-point source problems, some
regulatory approaches attempt to use economic instruments that indirectly provide
the farmer with the incentives necessary to alter manure-handling practices. This
approach has received a tremendous amount of interest due to theoretical studies
that suggest economic instruments can achieve a given environmental goal at a
lower cost than other policy alternatives. Futhermore, it is used throughout Europe
as a cornerstone for livestock waste management policies. Weersink and Livernois,
and Braden and Segerson evaluate several economic instruments for their potential
to reduce water pollution from agriculture.31 Economic instruments are of two
forms: performance-based and design-based.
Performance-based instruments are applied to target ambient levels of pollutants.
Those feasible for livestock agriculture include charges and subsidies, based on
the ambient environmental quality of the target water bodies or the watershed
in a given region, and liability rules. The levels of the charges or subsidies
depend on changes in ambient levels. As the measured ambient levels increase
relative to water quality objectives, producer charges are increased. If ambient
levels decrease below objectives, farmers may receive reward payments. Farmers
compare their costs of complying with the potential costs of ignoring the
ambient standards, and choose practices that are likely to maximize profit.
Such a policy theoretically provides producers with the incentive to determine
the lowest-cost practices for their operations to attain a given overall regional
standard. The correlation between individual farmers’ practices and ambient
nutrient concentrations is greater, and the instrument more effective, when
there are shorter time lags between on-farm activities and their associated effects
on water quality and when the number of producers in the region is relatively
small. However, in practice it is difficult to design and implement performancebased instruments in complex, multi-use watersheds.
Liability rules, as performance-based instruments, make producers responsible
for the costs of any water quality damages that they cause. These are only
suitable for cases in which there is clear evidence that a given water quality
damage event can be traced to a specific producer, for example, when manure
lagoons leak or overflow. But since most livestock waste and water quality
problems are diffuse, liability rules are most useful as a complementary
mechanism to other instruments.
31
Braden and Segerson, 1993; Weersink and Livernois, 1996.
26
Walkerton Inquiry Commissioned Paper 6
Design-based instruments, which include subsidies for adopting more benign
manure management or land-use management practices, tradeable permits,
and charges on outputs, are intended to affect production decisions by targeting
production inputs and outputs that are correlated with potential water quality
damages. Targeted subsidies (grants, loans, and tax allowances) may be granted
to producers who demonstrate that they have adopted management practices
to reduce their contribution to water quality problems. As discussed above,
subsidies have to be set at levels consistent with the corresponding impact on
water quality goals. Otherwise a single rate for all producers may encourage
some to incur costs that are more than the associated increase in water quality
while providing too low an incentive to others who could have a relatively
greater impact on water quality. Practical problems also include equity
considerations in cases where producers who had already been using
recommended practices are not eligible for subsidies that are intended as
incentives to encourage those who are still using undesirable practices to change.
The associated instrument of a tax or a charge for practices and inputs that are
considered detrimental to water quality objectives is considered to be
problematic for several reasons, including the infeasibility of charging differential
taxes to different producers based on farm type, region, and location in the
watershed. These differentials may be considered unconstitutional in some
jurisdictions, and producers may be able to substitute among inputs and
practices to avoid the tax in ways that simply change the water quality problem
without correcting it.32
Tradeable permits grant producers rights to produce at specific levels that are
correlated with expected levels of non-point water quality impairment. For
example, in the Netherlands, producers are granted Manure Production Rights
(MPRs) based on historical farm production records and land holdings.
Producers are able to buy and sell MPRs within regions, and between regions
if the sale is from a manure-surplus region to a manure-deficit region. Some
restrictions apply to markets for MPRs between livestock species and the
government can impose a “fee” on each transaction (a percent of the MPRs
traded). The effect of such a system is that farmers are allowed some degree of
discretion in how they manage their individual transitions in production
practices. Meanwhile the overall effect over time is to channel the market for
32
Lintner and Weersink, 1996.
The Management of Manure in Ontario with Respect to Water Quality
27
MPRs so as to achieve overall water quality goals within and between regions.
The regulator can gradually reduce the number of MPRs in the system, thereby
providing producers with a process that allows some individual adjustment
over time.
2.2.3 The Role of Individual Producer Discretion
Regulatory instruments vary in the degree of individual choice given to the
producer with regard to practices used to reduce impairment and the level of
diligence. However, as discussed above, using approaches that allow for greater
degrees of producer discretion does not necessarily imply that incentives are
weaker. Market-based economic instruments can be used to achieve water
quality goals in a given region while allowing producers the choice of how and
when to alter practices to achieve these goals.
Livestock waste management plans in the United States are another approach
that leaves some degree of producer discretion. These plans are developed by
producers with the support of specially trained USDA soil-conservation-service
staff members. These plans are developed to fit a combination of farm-specific
and watershed-specific goals. In some states, such plans are required in order
for producers to obtain permits for their livestock operations. The details of
each plan can be tailored to meet waste-management objectives in ways that
may differ substantially from farm to farm, yet be equally effective in reducing
water quality impacts. The underlying idea is that so-called ‘best management
practices’ are not necessarily ‘best’ in the sense of achieving water quality goals
at least cost when applied to all farm operations. Differences in watershed
features, farm locations, existing combinations of practices, and regional water
quality needs and goals may result in different estimations of the ‘best’
combinations of practices at any given farm. An advantage of discretionary
decision making is that farmers have incentives to innovate and find the most
cost-effective means to meet regulated standards. Individual innovations
contribute to technological advances that benefit the industry, while reducing
water impairment costs to society. The existing Environmental Farm Plan
program might be a starting point for similar regulatory programs in Ontario,
although at this time Environmental Farm Plans are not required, nor are
producers required to follow their plans.
28
Walkerton Inquiry Commissioned Paper 6
2.2.4 Coordinated Strategies
There is an increasing trend toward the achievement of explicit water quality
goals through strategic policies that incorporate combinations of mechanisms.
The USEPA recommends that policies be developed and examined at regional
levels.33 Similarly, a main recommendation of the most recent review of the
state of groundwater stocks and protection in the United States is greater
coordination of policies among institutions, within and among levels of
government, and across localities.34 The regional and explicit watershed
approach used at the federal and state levels is an example of coordination
strategies. Federal cost-share programs have had a significant coordination
impact both vertically between federal, state, and local levels of government,
and to a lesser degree horizontally between land-use and water quality policies.35
An interesting example of local strategic water-quality-policy development is
that of New York City. The purpose of the strategy was to maintain quality of
drinking water supplies so as to meet federal standards mandated by the
USEPA under authority of the Safe Drinking Water Act.36 Failure to meet federal
standards would require the city to implement expensive filter treatments or
be found in non-compliance with federal law. The first step in the strategy was
to conduct a systematic assessment of how existing regulations could be used
to protect water in the source watersheds and to identify the gaps in the existing
regulations, relative to their needs. Development of new mechanisms focused
on those situations that were not already adequately covered, which included
livestock waste handling by the region’s dairy producers. New livestock waste
management policies, developed as part of the strategy, are therefore integrated
into an overall plan for water quality protection.
The type of strategy employed by New York City involves integrating policy in
a systematic fashion over a combination of federal, state, county, and municipal
levels of government. Different levels of government often have limited sets of
33
U.S. Environmental Protection Agency (USEPA), Office of Wastewater Management and U.S.
Department of Agriculture (USDA), 1999, U.S. Department of Agriculture/U.S. Environmental
Protection Agency Unified National Strategy for Animal Feeding Operations, March 9, 1999 [online],
[cited February 12, 2002] <www.epa.gov/owm/finafost.htm>.
34
Ibid.
35
C. Johns, 2000, Non-point Source Water Pollution Management in Canada and the U.S.: A Comparative
Analysis of Institutional Arrangements and Policy Instruments, [unpublished dissertation, McMaster
University].
36
U.S. National Research Council (NRC), 1999, Watershed Management for Potable Water Supply:
Assessing the New York City Strategy, Report by the Committee to Review the New York City
Watershed Management Strategy (Washington D.C.: National Academy Press).
The Management of Manure in Ontario with Respect to Water Quality
29
policy tools, which can overlap or leave gaps. For example, in Ontario, municipal
governments may enact zoning by-laws, regulatory statutes are developed and
implemented at the provincial level, and water quality guidelines are set at the
federal level, which has limited authority to impose regulation. Overcoming
institutional barriers to achieve a systematic approach to regulation can be a
difficult and expensive process in itself. However, the administrative costs would
be apportioned over the relative efficiencies gained in water quality protection
from all types of impairments over the region for which the strategy is developed.
Similarly, such a strategy is more likely to result in apportioning the private
costs of regulation over the range of contributors to water quality impairment
problems (consistent with the “polluter pays” principle).
Finally, it must be noted that well-designed policies can justifiably combine
different regulatory instruments. The best combination of mechanisms for a
given jurisdiction depends on many features, such as:
•
•
•
•
•
•
•
•
existing legislation and levels of government responsibility,
the severity of existing water quality problems,
the costs imposed on society,
the costs of monitoring and enforcement,
the costs of providing necessary incentives for voluntary programs,
watershed-specific geological features,
the costs to farmers of altering practices, and
expectations of long-term industry trends toward increasing concentration
of livestock operations with attendant increases in the volumes of animal
waste per unit land area.
Where the benefits of minimizing water quality impairment are very large and
the desire to minimize risk is great, higher-cost regulatory devices are more
justifiable. Where the cost of water quality impairment is less, the use of cheaper
mechanisms with a larger voluntary component is more justified. In some cases,
the costs of treating municipal water may be cheaper than developing and
implementing policies to maintain water quality at levels that do not require
treatment. In other cases, the opposite may be true.
Since regions differ in their characteristics, optimal livestock waste management
policies will necessarily vary. Thus, while it is reasonable for a strategy to include
a variety of regulatory instruments, the combinations of instruments is likely
to differ among jurisdictions. The analogy is similar to the notion that the
efficacy of individual farm-level management practices is difficult to assess
without the context of the combination of practices that are used on the same
30
Walkerton Inquiry Commissioned Paper 6
farm, and the particular features of the region where the farm is located.
Achieving a given water quality goal at least cost could be attained by vastly
different combinations of practices at the farm level. Similarly, it is difficult to
assess the effectiveness of a given regulatory instrument outside the context of
its use, especially given the data limitations related to water quality that exist in
most jurisdictions.
The remainder of this section reviews several approaches used by different
jurisdictions. Different regions use different combinations of regulatory devices,
voluntary approaches, and market-based mechanisms. The section describes
what is in use today, according to written documentation, but does not attempt
to evaluate which approaches are ‘best.’
Some of these approaches result from recent policy assessments, which can be
time-consuming, research-intensive, and expensive processes. Some regions,
including Ontario, may not have yet undergone or completed such processes.
But because one approach works in a particular region, it does not necessarily
mean it is the optimal approach for another. So while it may be tempting to
suggest that a particularly innovative idea that works in Europe might work as
well in Ontario, such a conclusion is not justified without the appropriate
investment in research of the the needs and circumstances that face Ontario
producers and that apply to Ontario citizens who bear the costs of impaired
water quality from livestock production. The reader is encouraged to keep in
mind that stricter regulatory approaches are not necessarily the most effective
from the perspective of achieving set water quality goals at least cost to society.
Similarly, what appear to be the least expensive approaches from a regulatory
standpoint might actually be the most expensive from society’s standpoint, if
they are very inefficient at achieving water quality goals. Reviewing different
jurisdictions can provide some practical context by which to compare various
regulatory devices, voluntary approaches, and market-based instruments and
to consider their potential applicability in Ontario.
2.3 United States
Environmental impacts of livestock waste have recently received a lot of attention
in the United States. During the latter half of the 1990s, federal and state
governments initiated a number of studies to investigate the impacts of livestock
The Management of Manure in Ontario with Respect to Water Quality
31
operations on water quality and to assess the ability of existing regulations and
strategies to control these impacts.37
This sub-section describes the basic structure of the federal and state laws that
govern the regulation of water quality and the potential threat from manure
handling, and concludes with brief summaries of New York State and Kentucky
livestock waste policies. Kentucky was chosen because it has geological features
similar to those in parts of Ontario, namely fissured limestone, which potentially
allow surface water to affect groundwater stocks relatively more quickly than is
typical. And like Ontario, the majority of rural and small-municipal water supplies
in Kentucky come from groundwater. New York State has a similar livestock
agricultural industry as Ontario and also shares a common border.
2.3.1 Overview of Relevant U.S. Environmental Regulations
The system of institutional and legal authority in the United States differs
substantially from that in Canada. For example, the U.S. federal government
has greater authority to enact laws that regulate activity within local jurisdictions
than has the federal government in Canada. This structure allows a greater
degree of coordination between jurisdictions than is typically seen in Canada.
The greater level of federal authority in the United States generates greater
federal responsibility and support for local programs. Federal power over water
quality is, in part, mandated by the Clean Water Act and the Safe Drinking
Water Act. The USEPA is authorized by Congress to ensure that the provisions
of these Acts are met across the country. In general, all states must adhere to
USEPA standards and regulations, through either direct USEPA administration
or state administration under USEPA authorization. However, states may
develop water quality and manure management standards and regulations that
are stricter than the federal ones. For example, table 2-1 refers to states in
which discharge requirements exceed USEPA criteria.
The U.S. Safe Drinking Water Act (SDWA) provides the authority for
environmental regulations that directly target public health and the quality of
37
U.S. General Accounting Office (USGAO), 1995, Animal Agriculture: Information on Waste
Management and Water Quality Issues (Washington, D.C.); USGAO, 1999; USEPA, Wastewater
Management and USDA, 1999.
32
Walkerton Inquiry Commissioned Paper 6
drinking water at or near the point of use. The U.S. Clean Water Act (CWA)
focuses on the quality of source waters and discharges into those waters. The
USEPA administers both acts. Within the considerations of the CWA, water
quality programs are further divided into point source and non-point source
programs.
The SDWA, passed in 1974, sets allowable maximum contaminant levels (MCLs)
for finished drinking water. The safe water treatment rule (SWTR), under the
SDWA, describes the criteria that must be met by surface water supplies that
exempt them from expensive water filtration requirements. Most regulations
specifically aimed at groundwater tend to fall under the authority of the SDWA.
The Clean Water Act requires U.S. waters to meet quality levels that are fishable
and swimmable.38 States must classify waters according to their use and set specific
water quality criteria for those classifications. For waters not meeting the standards,
the CWA requires that sources of pollution be identified, total maximum daily
loads be developed, and mechanisms for reducing pollution be described.39
Point source pollution is defined in the U.S. Clean Water Act to include any
“discernable, confined, and discrete conveyance” and specifically includes
“concentrated animal feeding operations” (CAFOs). The definition of point
source exempts agricultural stormwater discharges. This exemption does not
apply when the discharge is associated with the land disposal of animal manure
originating from a CAFO or is not the result of proper agricultural practices.
For water quality problems that are identified as point source in nature, the
CWA authorizes the USEPA to administer the National Pollutant Discharge
Elimination System (NPDES). The NPDES defines CAFOs as point sources,
thus requiring such operations to qualify for permits that ensure that standards
are maintained and best available control strategies are used.40
Technically, the term non-point source (NPS) is defined to mean any source of
water pollution that does not meet the legal definition of point source in
section 502(14) of the Clean Water Act of 1987. “Non-point source pollution
results from precipitation, land runoff, infiltration, drainage, seepage, hydrologic
38
U.S. Environmental Protection Agency (USEPA), 1977, Clean Water Act, <www.epa.gov/region5/
defs/html/cwa.htm> and <www.epa.gov/epahome/laws.htm>.
39
U.S. NRC, 1999.
40
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
33
modification, or atmospheric deposition. As runoff from rainfall or snowmelt
moves, it picks up and transports natural pollutants and pollutants resulting
from human activity, ultimately depositing them into rivers, lakes, wetlands,
coastal waters, and groundwater.”
Regulation that targets surface NPS pollution tends to fall under the authority
of the CWA. Surface runoff from non-point sources has been identified as the
current largest contributing factor to water quality problems in the United
States, with livestock agriculture singled out as a significant problem. Although
CAFOs fall under the NPDES permit program, the majority of livestock
operations that contribute to runoff problems are smaller than the definition
of a CAFO and are therefore not considered point sources and do not require
permits. Several states have provided stricter definitions for granting permits
to livestock operations.
In response to the Clean Water Action Plan released in 1998, the USEPA and
the USDA developed a Unified Strategy to address livestock waste management.41
The Strategy elaborates and strengthens the requirements for CAFOs that are
regulated under NPDES permits, and provides numerous guidelines for voluntary
measures for smaller operations. The voluntary programs are supported by a
number of incentive mechanisms, including technical support, financial assistance,
and limited liability for operators who demonstrate appropriate management
measures. Details of this strategy are described later.
The distinctions between point source and non-point source, surface waters
and groundwater, and drinking water quality protection for public health and
water quality protection for broader environmental mandates can become rather
vague in many places. Provisions of the CWA and SDWA may overlap or not
provide even coverage. In such cases, individual states and municipalities may
develop specialized strategies to achieve water quality protection goals. For
example, the 1997 New York City Watershed Memorandum of Agreement
(MOA) outlines the watershed management strategy that protects drinking
water for nine million residents of New York City. The MOA creates watershed
rules and regulations that “fill in the gaps between the CWA and the SDWA.”42
The MOA addresses non-point pollution generated by livestock agriculture
within its Watershed Agricultural Program.
41
42
USEPA, Wastewater Management and USDA, 1999.
U.S. NRC, 1999.
34
Walkerton Inquiry Commissioned Paper 6
2.3.2 U.S. Regulations, Acts, and Programs Designed to Protect
Groundwater
Federal financial and technical support to municipalities and states for
developing groundwater protection plans is available through the Safe Drinking
Water Act and the Clean Water Act. While the CWA targets surface waters,
groundwater is included as it affects surface water through interconnected
groundwater stocks. Provisions of the CWA that relate specifically to livestock
agricultural wastes will be discussed in more detail below.
Section 1429 of the SDWA authorizes the USEPA to give grants to individual
states for the development and implementation of groundwater protection
programs.43 The USEPA is required to evaluate state-funded programs and
report to Congress every three years on the status of groundwater quality and
on the effectiveness of state programs to protect groundwater. Amendments to
the SDWA in 1996 authorized Congress to spend up to $15 million per year
from 1997 through 2003 to support the state programs.44
As of 1999, 47 states had approved wellhead protection programs that are
being expanded under the provisions of the 1996 SDWA amendments. Almost
every state has begun to implement comprehensive groundwater protection
programs, including enacting legislation and regulations, monitoring
groundwater quality, developing data management systems, and implementing
remediation and protection programs. The majority of federal funds allocated
for groundwater have been devoted to remediation as opposed to planning or
protection. The assessment of state programs resulted in recommendations for
more effective coordination of groundwater protection programs at the federal,
state, and local levels.45
While the SDWA has no specific provisions for the creation of groundwater
protection programs that relate to livestock waste, individual state programs
supported under the SDWA vary depending upon regional problems and
features. For example, Kentucky’s Agriculture Water Quality Act (1994) was
passed to protect surface and groundwater from agricultural pollution. The act
requires all land owners with 10 or more acres to develop and implement a
farm water quality plan.
43
U.S. Environmental Protection Agency (USEPA), Office of Water. 1999c. Safe Drinking Water
Act, Section 1429: Ground water Report to Congress, Final Report (Washington, D.C.), <gwpc.site.net/
gwreport/GWRindex.htm>.
44
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
35
2.3.3 Animal Feeding Operations Guidelines and Regulations
Animal Feeding Operations (AFOs) are agricultural enterprises where animals
are kept and raised in confined situations. Feed is brought to the animals,
rather than the animals grazing or otherwise seeking feed in pastures, fields, or
rangeland. Most livestock operations fall within this broad definition. For
regulatory purposes, it is useful to make distinctions between AFO types. The
USEPA definition46 considers that an AFO facility meets the following criteria:
•
•
animals have been, are, or will be stabled, confined and fed, or maintained
for a total of 45 days or more in any 12-month period and
crops, vegetation, forage growth, or post-harvest residues are not sustained
in the normal growing season over any portion of the lot or facility.
A Concentrated Animal Feeding Operation (CAFO) is defined as an AFO
facility that
•
•
confines more than 1,000 Animal Units (AUs)47
OR confines between 301 to 1,000 AUs and discharges pollutants into
waters of the United States through a man-made ditch, flushing system, or
similar man-made device, or directly into waters of the United States that
originate outside of and pass over, across, or through the facility or otherwise
come into direct contact with the animals confined in the operation.
According to the 1992 Agricultural Census, about 450,000 farm operations
nationwide met the conditions for AFOs. The vast majority are small farms,
with about 85% having fewer than 250 AUs.48 About 6,600 farms had more
than 1,000 AUs and are thus considered to be CAFOs by the USEPA. Between
1987 and 1992, the total number of AUs in the US increased by about 3%, or
4.5 million units. During this period, the number of AFOs decreased, indicating
a consolidation within the industry overall and greater production from fewer,
larger AFOs. Given industry trends, the USEPA and USDA believe that as
many as 10,000 CAFOs may exist in 2000.
45
Ibid.
Individual states may have slightly different definitions of AFOs and CAFOs, but any state-level
differences would result in regulatory control that is at least as strict as the federal definition.
47
1,000 Animal Unit equivalents: 1,000 slaughter and feeder cattle, 700 mature dairy cattle,
2,500 swine, 30,000 laying hens or broilers (if a liquid manure system) or 100,000 laying hens or
broilers if a facility uses continuous overflow watering.
48
USGAO, 1995.
46
36
Walkerton Inquiry Commissioned Paper 6
Wastes from AFOs can affect public health and water quality through direct
discharge into a surface water body or through runoff, either directly from the
facility or from manure applied to land. The USGAO estimates that 90% of
CAFO-generated waste is applied to land.49
The USEPA is currently revising its guidelines for CAFOs as a result of the 1999
USDA-USEPA Unified National Strategy for AFOs. Existing regulations affect
about 2,000 operations defined as CAFOs (having 1,000 or more AUs). New
regulations will likely increase the number of farms classified as CAFOs by
including restrictions for operations with unacceptable conditions and those that
are found to contribute significantly to water quality impairment within a specific
watershed. USEPA anticipates completing these guidelines by December 2001
for hog and poultry, and for beef and dairy operations in December 2002. The
USEPA anticipates that the new regulations will increase the number of operations
requiring federal permits from 5,800 to up to 20,000.50 A major impetus for
these reforms is the regulatory objective set by the Clean Water Act.
2.3.4 Livestock Waste Runoff and Non-point Source Pollution Policies
The Clean Water Action Plan (CWAP), released in February 1998, identified
runoff as the most important remaining source of water pollution in the United
States, with agricultural runoff from livestock waste listed as a specific target
for future action. The action plan noted that nationwide, 130 times more
animal waste than human waste is produced, or roughly 5 tons for each citizen.
The U.S. General Accounting Office reports that
AFOs are widely recognized to pose a number of risks to water quality
and public health, due to the amount of animal manure and
wastewater they generate. Animal waste runoff can impair surface
and groundwater by introducing pollutants, such as nutrients
(including nitrogen and phosphorus), organic matter, heavy metals,
sediments, pathogens (including bacteria and viruses), hormones,
antibiotics, and ammonia. Excess nutrients in water can contribute
to eutrophication, anoxia, and toxic algal blooms, and have been
associated in the United States with outbreaks of microbes such as
49
50
Ibid.
USGAO, 1999.
The Management of Manure in Ontario with Respect to Water Quality
37
Pfiesteria piscicida. Pathogens such as Crytosporidium have been
linked to impairments in drinking water supplies and threats to
human health. Pathogens in manure can also create a food safety
concern if manure is applied directly to crops at inappropriate times.
Nitrogen, in the form of nitrate, can contaminate groundwater
stocks. These pollutants are transported by rainwater, snowmelt, or
irrigation water through or over land surfaces and are eventually
deposited in rivers, lakes, and coastal waters or introduced into
groundwater. These can affect water quality and public health in
several ways, such as contaminating drinking water supplies and
killing fish and wildlife.51
Runoff from agricultural sources is a form of non-point source pollution. Nonpoint sources (NPS) are not subject to federal NPDES permit requirements
under the Clean Water Act. The USEPA strategy to abate non-point sources
focuses on land and runoff management practices, rather than on effluent
treatment.52 A 1987 amendment to the CWA created section 319, which is
intended to provide a national framework to address NPS pollution. Section
319 requires states to assess NPS pollution and implement management
programs. It also authorizes USEPA to issue grants to states for assistance in
implementing management programs. A recently published USEPA report gives
technical assistance to state program managers and others on “the best available,
economically achievable means of reducing non-point source pollution of
surface and groundwater from agriculture.”53 Finally, in addition to increasing
funding to the USDA programs by $100 million, the CWAP doubled federal
funding for the federal NPS Program to $200 million annually.
2.3.5 Regulation of Point Source Pollution from Livestock Waste
The primary device for point source pollution regulation in the United States is
the National Pollutant Discharge Elimination System (NPDES), administered
by the USEPA under the authority of the Clean Water Act. The program defines
and classifies categories of point source pollution, and based on these definitions,
firms may be required to apply for a permit. Depending upon the nature of the
51
Ibid.
U.S. Environmental Protection Agency (USEPA), Office of Water, Nonpoint Source Control Branch,
2000, National Measures to Control Non-point Source Pollution from Agriculture, Draft Report.
53
Ibid.
52
38
Walkerton Inquiry Commissioned Paper 6
activity and the pollutant, the permits specify the circumstances under which the
firm is allowed to operate. The USEPA issues NPDES permits directly, or individual
states may be authorized to implement the NPDES program provided that the state
NPDES program requirements are as at least as stringent as those imposed under
the federal program. NPDES permits are for five years. The general public may
participate in NPDES permit decisions. The procedures require that the public be
notified and allowed to comment on NPDES permit applications.
The federal NPDES requirements specifically include regulation of Concentrated
Animal Feeding Operations (CAFOs). CAFOs are defined as point sources for
the purposes of the NPDES program; no such facility may discharge pollutants
from a point source to waters of the United States without an NPDES permit,
except for discharges resulting from a 25-year, 24-hour storm event.
The current USEPA policy treats only those AFOs that meet the regulatory
definition of a CAFO as a point source, and thus are subject to the NPDES
program.54 About 2,000 CAFOs have been issued NPDES permits by the
USEPA and individual states under section 402 of the CWA. These permits
limit conditions under which discharges may be made from point sources and
may also impose best management practices (BMPs). For example, poultry
operations that remove waste from pens and stack it in areas exposed to rainfall
or adjacent to a watercourse may be considered to have established a liquid
manure system and therefore CAFOs are subject to the NPDES program.
USEPA expects that between 15,000–20,000 CAFOs require permitting and
enforcement under NPDES permits.55
Under authorization of USEPA, individual states may implement their own
programs. The federal program targets CAFOs, but state regulations may be
more stringent and include AFOs as well. State non-NPDES programs (state
AFO programs) are typically more stringent than the federal NPDES program,
thus many states authorized to implement the federal program choose not to.
While state AFO programs vary, most regulate facilities through permitting
programs that require animal waste disposal systems to be constructed to prevent
the discharge of wastes to surface waters. As of 1999, more than 45,000 nonNPDES permits have been issued via state-level AFO programs.56
54
Another regulatory program that addresses AFOs is the Coastal Non-point Pollution Control
Program, implemented under the authority of the Coastal Zone Act Reauthorization Amendments of
1990.
55
USEPA, Wastewater Management and USDA, 1999; USGAO, 1999.
56
USEPA, Wastewater Management and USDA, 1999.
The Management of Manure in Ontario with Respect to Water Quality
39
Currently 43 states have AFO program requirements that are as stringent as
the federal requirements. Their CAFO requirements are often more stringent
than the federal requirements. CAFO permit conditions may also address land
application of wastes. CAFO operators are typically required to apply waste at
agronomic rates and to develop waste management plans. The waste
management plan requirements vary by state. About 2,000 NPDES permits
for CAFOs have been issued in the U.S.57
2.3.6 USDA-USEPA Unified National Strategy for Animal Feeding
Operations (AFOs)
The 1998 Clean Water Action Plan (CWAP) recommended the development
of a unified USDA-USEPA national strategy to minimize the impacts of AFOs
on water quality and public health. The unified strategy was released in March
1999. At present, the USEPA, USDA, and state-level agencies are revising
their guidelines to reflect its recommendations.
The USDA-USEPA Unified National Strategy for Animal Feeding Operations
includes several guiding principles:58
1.
2.
3.
4.
5.
6.
To focus on AFOs that represent the greatest risks to the environment
and public health.
To ensure that measures to protect the environment and public health
complement the long-term sustainability of livestock production in the
United States.
To establish a national goal and environmental performance expectation
for all AFOs.
To promote, support, and provide incentives for the use of sustainable
agricultural practices and systems.
To make appropriate use of diverse tools including voluntary, regulatory,
and incentive-based approaches.
To focus technical and financial assistance to support AFOs in meeting
national goals and performance expectations established in the Strategy.
The USDA-USEPA unified national strategy recommends a combination of
voluntary and regulatory programs to serve complementary roles in helping AFO
57
58
Ibid.
USEPA, Wastewater Management and USDA, 1999.
40
Walkerton Inquiry Commissioned Paper 6
operators to achieve individual business goals, protection of water quality, and
public health objectives. The regulatory program focuses on permitting and
enforcement priorities on high-risk operations, which are a small percentage of
AFOs. For most AFOs, a variety of voluntary programs provide the technical and
financial assistance to help producers meet technical standards and remain
economically viable.59
2.3.6.1 Voluntary programs for AFOs
The strategy sets a national performance expectation that by 2009, all of the
approximately 450,000 AFOs nationwide should develop and implement
technically sound, economically feasible, and site-specific Comprehensive Nutrient
Management Plans (CNMPs) to minimize impacts on water quality and public
health. The CNMPs would address feed management, manure handling and
storage, land application of manure, land management, record keeping, and other
utilization options. The plans should address risks from pathogens and other
pollutants as well as nutrients. The owner or operator is ultimately responsible
for the development and implementation of CNMPs regardless of who provides
technical assistance. The Natural Resources Conservation Service (NRCS) Field
Office Technical Guide for any given region is the primary technical reference
for the development of CNMPs for AFOs. Specific management practices would
be expected to vary to reflect site-specific conditions or needs of the watershed.60
These plans should include provisions to
•
•
•
•
59
modify animal diets to reduce nutrients in manure;
improve manure handling and storage to reduce chances of leaks or spills;
apply manure to cropland in a manner that does not introduce an excess
of nutrients and minimizes runoff; and/or
employ alternative uses of manure such as selling it to other farmers,
composting it and selling compost to homeowners, and generating power
on the farm where the potential for land application is limited.61
Ibid.
A more detailed listing and description of the various practices that livestock and poultry AFO
operators may use to manage animal wastes are found in USDA publications, including the National
Handbook of Conservation Practices (USDA/NRCS, April 26, 1999), <www.ftw.nrcs.usda.gov/
nhcp_2.html>, and Natural Resources Conservation Service (NRCS) Field Office Technical Guides
(derived from the handbook) at NRCS field offices in each state. The NRCS is part of the USDA.
61
USEPA, Wastewater Management and USDA, 1999.
60
The Management of Manure in Ontario with Respect to Water Quality
41
The primary effort of the voluntary strategy will be to assist operators in
developing CNMPs. While these are not mandatory for AFOs in voluntary
programs, they are strongly encouraged as the best possible means to manage
potential water quality and public health impacts.
States are expected to support development of voluntary CNMPs consistent with
other clean water program priorities. AFO operators are expected to be full partners
in the development and implementation of CNMPs through voluntary programs.
The successful implementation of voluntary programs is expected to require the
support of local leadership. A key feature will be environmental education of
AFO operators adhering to older BMPs, who are unintentionally contributing
to runoff problems due to lack of access to new information. Financial cost-share
and loan programs are recommended to provide AFO operators with incentives
to participate in voluntary programs. Many states have financial assistance
programs that supplement Federal assistance.62
AFO owners/operators are encouraged to participate in other state and federal
programs to improve water quality and implement runoff abatement activities,
including state cost-share programs and the USEPA’s National Agriculture
Compliance Assistance program authorized under the Clean Water Act. All
USDA, USEPA, federal, state, and local programs are expected to be used
together as tools to leverage resources to help AFO owners to voluntarily address
water quality and public health impacts.
2.3.7 Federal Financial Assistance for Animal Waste Management
The USDA administers the major federal programs that deliver financial and
technical support to producers to manage animal wastes. Most assistance is
provided through the USDA’s Environmental Quality Incentives Program
(EQIP), established by the 1996 Farm Bill to provide a voluntary conservation
program for farmers and ranchers. Half the funds must be directed toward
livestock-related concerns. Cost-sharing may pay up to 75% of the costs for
certain practices. Incentive payments may be made to encourage producers to
adopt nutrient and manure management practices. Funding priorities are based
on the importance of the environmental problem addressed and the ability to
address the problem with the available funds, with the goal of maximizing the
environmental benefits for each EQIP dollar spent.63
62
63
Ibid; USGAO, 1999.
USGAO, 1999.
42
Walkerton Inquiry Commissioned Paper 6
The EQIP program shares costs of implementing waste management strategies
with farmers through direct payments. Additional programs are administered
by the USEPA or the Fish and Wildlife Service of the Department of Interior.
Producers generally learn about programs and assistance through local officials,
who help them select waste management practices and apply for financial
assistance. For fiscal years 1996 through 1998, federal agencies provided $384.7
million plus technical assistance to producers; they estimated they would provide
about $114 million in fiscal year 1999. USDA provides about 85% of the
available financial assistance, while the USEPA provides about 10% and the
Fish and Wildlife Service provides most of the remaining 5%. Table 2-2 shows
the breakdown of funding for animal waste management by program. Individual
animal waste management practices supported by the USDA EQIP program
and the costs of implementing them are summarized in table 2-3.
The Conservation Reserve Program (CRP) was authorized by the 1985 Farm
Bill. It is a voluntary program that offers annual rental payments, incentive
payments, and cost-share assistance for long-term cover-crops on highly erodible
land. Land is accepted into the CRP through a competitive bidding process
where all offers are ranked using an environmental benefits index.64
Federal expenditures for animal waste management research in the United States
is largely funnelled through the USDA’s Agricultural Research Service (ARS)
and Cooperative State Research, Education and Extension Service (CSREES).
The ARS research is done primarily through its National Program for Manure
and By-Product Utilization, which has focused on non-structural practices such
as alternative feeds and land-based manure management practices. Between 1996
and 1998, ARS spent $13.5 million for research related to animal waste
management, and estimates that $9.1 million was spent in 1999. The growth in
funding allocations is a result of public concern about environmental and health
issues. CSREES provides funds to state agricultural experiment stations,
universities, and other institutions. Nearly 400 projects in 1997, costing about
$6.9 million, were related in part to animal waste management. Research included
combining aerobic and anaerobic methods to treat wastes, and combustion of
poultry litter for electricity generation. Estimates for 1998–1999 costs are not
available. Individual states and private organizations also fund research on animal
waste management practices.65
64
65
Ibid.
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
43
Table 2-2 U.S. Programs Providing Financial and Technical Assistance
for Animal Waste Management
Program
Program Description
Amount
Amount
Provided
Estimated
FY 1996–98
FY 1999
($ million US) ($ million US)
USEPA Programs
National Nonpoint Source
Program
Provides grants to states to (1) assess the extent to which
non-point sources cause water quality problems and
(2) develop management programs to address these
problems. Several states have used these USEPA grants to
assist livestock and poultry producers install animal waste
management practices.
17.6
Not available a
Clean Water
State Revolving
Fund
Provides capitalization grants to states, which must
provide a matching amount equal to 20% of the total
grant and agree to use the money first to ensure that
wastewater treatment facilities are in compliance with the
deadlines, goals, and requirements of the Clean Water
Act. All states have met their priority wastewater infrastructure needs, and some have begun using this
revolving fund to support programs to deal with nonpoint source pollution, including animal waste runoff.
Some states use this funding to make low-interest loans
to producers for implementing animal waste management
practices.
20.3 b
Not available a
AgSTAR
Provides technical assistance to producers interested in
installing waste management systems, such as covered
lagoons and anaerobic digesters that reduce odours and
recover methane gas for use as an on-farm power
source.The program has established several projects on
farms in at least five states.
1.9
0.4
208.9
87.0
USDA Programs
Environmental
Quality
Incentives
Program (EQIP)
a
Provides financial and technical assistance to producers
who agree to enter 5- to 10- year contracts to implement
conservation practices. Generally shares up to 75% of the
costs to install practices, with a maximum of $10,000 for
any fiscal year, or $50,000 for any multiyear contract.
Program also provides incentive payments for nutrient
management initiatives. Focuses on priority areas such as
watersheds with environmental concerns. At least 50% of
EQIP funding is reserved to assist livestock and poultry
producers; these producers must have fewer than 1,000
animal unit equivalents.
These program funds are distributed by state and local governments according to local priority needs. As a
result, USEPA is unable to estimate the portion of these funds that will be used to assist producers in
managing their animal wastes.
b
States have only reported to USEPA the aggregate amount of loans made for animal agricultural runoff since
they began using these funds for non-point source pollution-related activities. Hence, some states may have
been providing loans for this purpose since 1988. However, USEPA officials said that most states began using
these funds for non-point source projects in the mid-1990s.
44
Walkerton Inquiry Commissioned Paper 6
Table 2-2 U.S. Programs Providing Financial and Technical Assistance
for Animal Waste Management, cont’d.
Program
Program Description
Amount
Amount
Provided
Estimated
FY 1996–98
FY 1999
($ million US) ($ million US)
USDA Programs (continued)
Small
Watershed
Program
Provides financial and technical assistance through state
and local agencies to producers who usually enter 5- to
10- year contracts to implement management practices.
Generally shares from 50 to 75% of the actual costs
associated with installing management practices, with a
maximum of $100,000 per participant for the life of the
program. Focuses on watersheds smaller than 250,000
acres.
49.6
17.9
Agricultural
Conservation
Program
A terminated program that provided financial and
technical assistance to producers who entered multiyear
contracts to install conservation practices. Generally
shared up to 50% of the costs to implement practices,
with a maximum of $3,500 annually and $35,00 for a 10year contract. USDA is still making payments under some
of these contracts.
62.0
Not available
Conservation
Provides land rental payments, for 10 to 15 years, to
Reserve Progam producers who agree to convert highly erodible or other
environmentally sensitive land to approved vegetated
cover (such as grasses or trees). Program also offers costshare assistance to establish vegetated cover and fencing
on enrolled land.
5.9
Not available
Farm ownership Provides direct loans of up to $200,000, or guaranteed
loans
loans of up to $300,000 for up to 40 years to, among
other things, purchase land, construct buildings or make
other structural improvements, and develop farmland to
promote soil and water conservation.
c
c
Farm operating Provides direct loans of up to $200,000, or guaranteed
loans
loans of up to $400,000 for up to 7 years to, among
other things, purchase livestock, poultry, equipment, feed,
and other farm supplies; develop and implement soil and
water conservation practices; and refinance debt.
c
c
Fish and Wildlife Service, Department of the Interior
Partners for Fish Provides cost-share and technical assistance to private
and Wildlife
landowners, including livestock and poultry producers,
who are interested in implementing practices that
improve habitat for federal trust speciesd, decrease
overland runoff, reduce stream degradation, and improve
forage production and management. Cost-share assistance
under the partners program generally requires a 50%
match from the landowner. However, the program has
the flexibility to share costs of more or less than 50%, on
a case-by-case basis.
c
18.3
8.7
Loans not tracked for specific soil and water conservation practices, or whether the loan recipient is an animal
producer.
d
Federal trust species include migratory birds, threatened and endangered species, anadromous fish (fish that
migrate between fresh and salt waters, such as salmon), and marine mammals.
The Management of Manure in Ontario with Respect to Water Quality
45
Table 2-2 U.S. Programs Providing Financial and Technical Assistance
for Animal Waste Management, cont’d.
Program
Programy Description
Farm
Assessment
System
(Farm*A*Syst)
Supports a network of 45 state programs. The program
provides producers with state-specific worksheets to help
them identify and assess the causes of non-point source
pollution, pinpoint pollution risks on their property, and
identify site-specific actions to reduce the causes of nonpoint source pollution, such as nitrogen and phosphorus
nutrients, pesticides, and pathogens. This assessment can
assist producers in developing feasible plans to prevent
pollution and in locating sources of financial assistance
through other programs, such as EQIP, to implement
practices such as those for managing animal wastes.
Amount
Amount
Estimated
Provided
FY 1999
FY 1996–98
($ million US) ($ million US)
0.2 e
0.06
e
TOTAL
e
According to Farm*A*Syst officials, no USEPA funds have been directed toward animal waste management
activities, only USDA funds have been used.
Source: USGAO, 1999.
2.3.8 Best Management Practices (BMPs) Recommended in the United
States
The USDA-USEPA Unified National Strategy for AFOs sets a national
performance expectation: all AFO owners and operators must develop and
implement technically sound and economically feasible, site-specific,
comprehensive nutrient management plans (CNMPs) by 2009.66 A CNMP
identifies actions that will be implemented to meet clearly defined nutrient
management goals at an agricultural operation. Components of a CNMP
include feed management, manure handling and storage, land application of
manure, land management, record keeping, and other options for manure use
such as composting and power generation.67
The National Agriculture Compliance Assistance Center (NACAC) provides
an outline and source material that describes the basic components of the
USEPA’s guidelines for recommending specific management practices to control
the impact of livestock waste on water resources.68 The USDA-USEPA unified
66
USEPA, Wastewater Management and USDA, 1999.
USGAO, 1999.
68
This outline, plus links to additional resources on best management practices, is available online
at <http://es.epa.gov/oeca/ag/sectors/animals/anafobmp.html>.
67
46
Walkerton Inquiry Commissioned Paper 6
Table 2-3 Selected Practices Installed with EQIP Assistance and
Average Installation Costs ($US)
Average
Installation cost
$US per unit
Practice
Definition/purpose
Composting
Facility for the biological stabilization of waste organic material.
Cover and green
manure crop
Close-growing legumes or small grain to control erosion during periods when
the major crops do not furnish adequate cover. Possesses filtering qualities.
$24.90/acre
Diversion
Channel constructed to divert excess water from one area for use or safe
disposal in other areas.
$3.10/foot
$8,409/facility
Fence
Constructed barrier to livestock, wildlife, or people.
$1.54/foot
Filter strip
Area of vegetation for removing sediment, organic matter, and other
pollutants from runoff and wastewater. May require a constructed ditch
(‘ setting basin‘ ) between a barnyard and the vegetative strip to ensure that
solids do not reach surface waters.
$4,650/acre
Grassed waterway
Natural or constructed channel that is shaped and established in vegetation
to convey runoff from water concentrations without causing erosion or
flooding and to improve water quality.
$2,644/acre
Manure transfer*
Conveyance system, such as pipelines and concrete-lined ditches, that
transfer animal waste (manure, bedding material, spilled feed, process and
wash water, and other residues associated with animal production) to (1) a
storage or treatment facility, (2) a loading area, and (3) agricultural land for
final utilization.
$10,932/system
Nutrient
management
Managing the amount, form, placement, and timing or applications of
nutrients, such as farm animal waste, for optimum crop yields while
minimizing the entry of nutrients to surface water and ground water.
Roof runoff
management
Gutters, downspouts, and drains for controlling roof runoff water to prevent
this runoff from flowing across feedlots, barnyards, or other areas to reduce
pollution and erosion; improve water quality; and prevent flooding.
$17.10/acre
$3,098/facility
Streambank and
Vegetation or structures used to stabilize and protect banks of streams, lakes,
shoreline protection and estuaries to reduce sediment loads – including nutrients from animal
waste – causing downstream damage and pollution.
$27.11/foot
Trough or tank
$905/trough
or tank
Provides drinking water for livestock, which can eliminate the need for
livestock to be in streams; this, in turn, reduces the amount of livestock waste
entering streams.
Waste management Planned system in which all necessary components are installed for
system
managing liquid and solid waste, including runoff from concentrated waste
areas, in a manner than does not degrade air, soil, or water resources. A
system may consist of a single component, such as a diversion, or of several
components.
$20,477/system
Waste storage facility Impoundment made by constructing an embankment and/or excavating a pit
or dugout or by fabricating a structure to temporarily store wastes, such as
manure, wastewater, and contaminated runoff.
$19,141/facility
Waste treatment
lagoon*
Impoundment made by excavation or earthfill for biological treatment of
animal or other agricultural waste.
$20,777/lagoon
Waste utilization
Agricultural waste applied to land in an environmentally acceptable manner
while maintaining or improving soil and plant resources.
$17.10/acre
*Because fewer than 30 of these systems or facilities have been completed under EQIP, the average cost may not
reflect a statistically valid estimate.
Source: USGAO, 1999.
The Management of Manure in Ontario with Respect to Water Quality
47
national strategy is currently developing guidance and assessment tools,
numerical criteria, software, and other support for regions to develop their
management measures. The USEPA will assist states in adopting the criteria
into their water quality standards by 2003.
The strategy does not prescribe specific best management practices, but rather
specifies “management measures,” defined as “economically achievable measures
to control the addition of pollutants to our coastal waters, which reflect the
greatest degree of pollutant reduction achievable through application of the best
available non-point pollution control practices, technologies, processes, siting
criteria, operating methods, or other alternatives.”69 Individual states are
expected to specify the particular practices and technologies that achieve
pollution control measures, appropriate for the site conditions, climate,
geography, type of operations, and other features that are particular to the
region. Thus, management measures are broad goals, and the individual regions
are expected to determine what practices are most appropriate given specific
features of their areas.
The principle is to avoid defining particular management practices as BMPs,
because ‘best’ is a potentially subjective term, depending upon individual goals,
and is highly site-specific. Even within regions, a management practice that
may be considered ‘best’ in one area may be inappropriate in another, depending
upon priorities, goals, and site-specific and watershed-specific features.
Management practices may be structural (waste treatment lagoons)
or managerial (nutrient management). Management practices
generally do not stand alone in solving water problems, but are used
in combinations to build management practice systems. Each
practice should be selected, designed, implemented, and maintained
in accordance with site-specific considerations to ensure that the
practices function together to achieve overall management goals.70
69
U.S. National Agriculture Compliance Assistance Center (NACAC), 2000, Best Management
Practices (Animals), <http://es.epa.gov/oeca/ag/sectors/animals/anafobmp.html>.
70
USGAO, 1999.
48
Walkerton Inquiry Commissioned Paper 6
The emphasis is to develop coordinated groups of affordable management
practices that can be used together as a system to achieve comprehensive goals
at specific sites, without recommending any particular practice outside the
context of an overall goal. A group of practices is termed a “management
measure.” USGAO71 suggests that the factors that should influence the choice
of management practices for a management measure include:
•
site-specific factors, type and volume of waste, and proximity to surface
or groundwater;
cost considerations; and
state and local regulations.
•
•
Recommended components of management measures for AFOs include:
•
Divert clean water: Siting or management practices should divert clean
water (run-on from uplands, water from roofs) from contact with holding
pens, animal manure, or manure storage systems.
•
Prevent seepage: Buildings, collection systems, conveyance systems, and
storage facilities should be designed and maintained to prevent seepage
to ground and surface water.
•
Provide adequate storage: Liquid manure storage systems should be
(a) designed to safely store the quantity and contents of animal manure
and wastewater produced, contaminated runoff from the facility, and
rainfall from the 25-year, 24-hour storm, and (b) consistent with planned
use and schedules. Dry manure should be stored in production buildings
or storage facilities, or otherwise covered to prevent precipitation from
coming into direct contact with the manure.
•
Application: Apply manure in accordance with a nutrient management
plan that meets the performance expectations of the management measure.
•
Address lands receiving wastes: Areas receiving manure should be managed
in accordance with the erosion and sediment control, irrigation, and
grazing management measures as applicable, including practices such as
crop and grazing management practices to minimize movement of applied
materials, and buffers or other practices to trap, store, and ‘process’
materials that might move during precipitation events.
71
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
49
•
Record keeping: AFO operators should keep records that indicate the
quantity of manure produced and its use or disposal method, including
land application.
•
Consider the full range of environmental constraints and requirements: When
siting new facilities or expanding existing ones, operators should consider
the proximity to surface waters, areas of high leaching potential, and sink
holes or other sensitive areas.
The same study compared practices used in other countries with those in the
United States and found general similarities.72 Most practices are based on the
eventual application of waste to agricultural land as a fertilizer or soil conditioner.
Reviewed waste management practices functioned to
•
limit runoff by cementing and curbing animal confinement areas or
planting grassed buffers around these areas;
•
collect and store waste, e.g., with scraping or flushing systems, storage
tanks, or retention ponds;
•
alter or treat waste, e.g., by reformulating feed mixes or composting;
•
use waste, e.g., as an organic fertilizer, as an additive to animal feed, or for
on-farm energy generation, using methane produced from anaerobic
decomposition of wastes in covered lagoons or tanks.73
The study noted some differences in approach and emphasis between countries
that relate to differences in political and economic circumstances. The use of
anaerobic digesters to produce methane for on-farm energy generation is
more prevalent in Europe than in the United States. Germany alone has
approximately 400 digesters, compared with 28 on U.S. farms. USEPA,
USDA, and Dept. of Energy officials indicate that the relatively low cost of
energy in the United States as compared to Europe make these options less
attractive to U.S. farmers.
Some European countries, such as Denmark, Germany, and the Netherlands,
have quasi-government or commercial companies that operate centralized plants
that accept organic waste material for anaerobic digestion. These plants produce
72
73
Ibid.
Ibid.
50
Walkerton Inquiry Commissioned Paper 6
and market the by-products of digestion, including methane gas, nutrient-rich
fertilizers, and compost. The plants collect user fees from farms, firms, and
municipalities that supply the waste. Some receive government subsidies to
cover operating expenses. By 1997, about 40 such plants in Europe received
animal wastes, compared with only two plants in the United States. The
discrepancy is due in large part to the relative differences in energy prices, costs
of regulatory compliance, and the amount of available land for application of
organic wastes.74
Animal waste is used for commercial energy production in some European
countries. These plants require government subsidies to remain competitive
with plants that use fossil fuels.75
Some countries have imposed specific nutrient management regulations.
Denmark, Japan, the Netherlands, Sweden, and the UK regulate and limit
application of animal wastes to agricultural lands. Denmark requires that farmers
meet specific cropland acreage-to-animal ratios.
USEPA officials have investigated municipal sewage treatment technologies
for the treatment of wastewater and sewage from large dairy and hog operations.
They concluded that the technologies would require significant modifications
to handle the more concentrated wastes from farm operations. Also, the capital
investment and operating and maintenance costs would be very high. The
construction of such on-farm treatment plants may require financial assistance,
as is often the case for municipal facilities. Producers may have access to
specialized funds and loans through the Clean Water Act. The USEPA notes
that municipal sewage systems with excess capacity may handle animal wastes,
such as one facility in southern California that accepts animal wastes from a
nearby dairy farm. Such treatment processes still result in a residual sludge that
must either be landfilled, incinerated, or applied to agricultural lands.76
74
Ibid.
Ibid.
76
Ibid.
75
The Management of Manure in Ontario with Respect to Water Quality
51
2.3.9 State-level Regulations for Non-point Source Pollution77
A study prepared for the USEPA by the Environmental Law Institute examined
the laws of all 50 states to identify and analyze enforceable mechanisms for the
control of non-point source water pollution.78 The study highlighted the great
diversity in legislation among states. The study also emphasized that it is not
possible to assess the effectiveness of enforceable mechanisms to deal with specific
problems in a state outside the context of the state’s entire program. Agriculture
was noted as the most problematic area for enforceable mechanisms, in part
because many laws and regulations include exemptions for agriculture. State laws
regarding water pollution from agriculture often rely on incentives, cost-sharing,
and voluntary programs instead of enforceable regulatory mechanisms.79
State laws tend to delegate standard setting, implementation, or enforcement
duties to units of local government or conservation districts. About a quarter
of the states authorize individual soil and water conservation districts to adopt
enforceable “land-use regulations.” However, most of these require approval
by landowner referenda, with approval requiring a 66% to 90% majority vote.
Kentucky, for instance, requires approval from at least 90% of the landowners.80
Some examples of these are described in Section 2.4.
Agricultural nutrient regulation is typically through state CAFO regulations,
similar to the federal requirements but with variations on the number of animal
units or with the addition of siting requirements. Some states have adopted
enforceable codes of accepted agricultural practices or nutrient regulations.
Some provisions allow districts to order abatement of agricultural pollution.
Several of these laws provide that abatement cannot be ordered unless state or
federal cost-share money is provided to help pay for the required action.81
77
Another source that discusses state-level regulations is W.R. Lowry, 1992, The Dimensions of
Federalism: State Governments and Pollution Control Policies (Durham, NC: Duke University Press).
78
Environmental Law Institute (ELI), 1997, Enforceable State Mechanisms for the Control of Nonpoint
Source Water Pollution (Washington, D.C.), <www.epa.gov/OWOW/NPS/elistudy/index.html>.
79
Ibid.
80
Ibid.
81
Ibid.
52
Walkerton Inquiry Commissioned Paper 6
Many states have mechanisms to make BMPs, if not enforceable, at least more
than voluntary by linking them to other enforcement mechanisms. The study
identified five approaches currently in use by various states:
•
•
•
•
•
make BMPs directly enforceable in connection with required permits
and planning approval;
make BMPs enforceable after the fact, when a “bad actor” is causing
pollution;
make BMPs the basis for an exemption from a regulatory program;
make compliance with BMPs a defence to a regulatory violation; and
make compliance with BMPs a defence to nuisance actions.
The study noted that the most sophisticated state regulations appear to be
arising on a targeted watershed basis. For example, Wisconsin integrates soil
and water conservation districts into the planning, administration, and
enforcement scheme.
2.3.10 State Livestock Waste Management Regulations in Kentucky
The USEPA’s State Compendium Programs and Regulatory Activities Related to
Animal Feeding Operations provides details about individual state regulations
that are in addition to the federal USEPA requirements. This subsection,
featuring Kentucky and New York, is largely based on the Compendium and
on information provided by the Kentucky Department for Environmental
Protection Web site.82
The state of Kentucky issues Kentucky No Discharge Operational Permits to
AFOs, with more than 1,200 being issued to beef, dairy, and swine operations
by 1999. In 1998, Kentucky imposed a moratorium on the expansion of hog
AFOs until state management and regulatory plans could be developed.
Regulation 401 KAR 5:009 (permits for swine-feeding operations) went into
effect in November 1998, but was later found to be too restrictive. It was to be
replaced during 2000.
As of 1999, about 50 livestock facilities in Kentucky met or exceeded the USEPA
CAFO definition and therefore required NPDES program permits. In addition,
82
Kentucky Department for Environmental Protection (KDEP), 2000, An Overview of Kentucky’s
Waters [online], [cited February 12, 2002], <www.water.nr.state.ky.us/dow/dwover.htm>.
The Management of Manure in Ontario with Respect to Water Quality
53
a state-level non-NPDES individual permit is required of CAFOs. Permit
conditions cover effluent, management, and land application of wastes. Land
application permits cover both agronomic rates and offsite disposal.
The Kentucky Department of Environmental Protection, Division of Water,
administers Kentucky’s NPDES program under authority of the USEPA. The
Division of Water is also responsible for issuing waste permits and administers
the voluntary non-point source pollution grant program. The NPDES program
issues permits and is administered through the Kentucky Division of Water’s
Discharge Elimination System. In addition to the NPDES permits, the Division
of Water issues two types of state permits that directly affect AFOs:
•
Wastewater Facility Construction Permits are required prior to beginning
construction or modification of any sewage system used for treatment of
wastewater. This permit requires detailed plans that describe discharge
points and highlight new construction features. An engineering report
must be submitted before construction is authorized. After construction,
the applicant must submit certification by a registered engineer that the
facility was constructed according to the approved plans.
•
Swine Waste Management Permits, part of the emergency swine-feeding
operations regulation, is required of all new swine-feeding operations with
over 1,000 animals, and of any existing operations that increase capacity.
The regulations include construction and operational requirements for
swine waste lagoons and the land applications of waste from the lagoons.
The regulations also provide siting regulations for waste lagoons,
restrictions on land applications, and monitoring and testing requirements.
Each operation must develop a waste management plan that describes
the crop nutrient requirements, how waste will benefit the surrounding
land, and when and where it will be applied. A monitoring plan requires
the permittee to conduct groundwater monitoring and maintain records
for 10 years.
A barn or waste lagoon cannot be located in a 100-year floodplain or a
jurisdictional wetland, nor within 150 feet of a lake or river. Land application
of livestock waste is not allowed within 150 feet of water wells. Waste
management system operators who intend to apply liquid hog manure must
take soil samples from the fields to be treated and complete an analysis of
swine waste nutrient content. Land application is not allowed on saturated
ground, during precipitation, or on frozen ground, and waste must not be
54
Walkerton Inquiry Commissioned Paper 6
applied at a rate that exceeds infiltration. All swine waste application areas
must have a filter strip on its lowest side.
Kentucky prohibits the discharge of any pollutant or substance that shall cause
or contribute to water pollution “in contravention of any rule, regulation,
permit, or order” (Ky. Rev. St. 224.70-110). The law provides that if a violation
is traceable to an agricultural operation, it is handled under the state’s enforceable
Agriculture Water Quality Act, rather than under the stricter water pollution
control act (Ky. Rev. St. 224.120(10)).83
The Agriculture Water Quality Act (1994) was passed to protect surface and
groundwater from agricultural pollution. The act requires all landowners with 10
or more acres to develop and implement a farm water quality plan based on guidance
from a Statewide Water Quality Plan (Ky. Rev. Stat. 224.71-100 to 71–145). Some
technical and financial assistance is available during development. Section 319
Non-point Source Implementation Grants, under the CWA, can cover up to 60%
of the total cost of voluntary pollution control projects.
Landowners must use BMPs for their plans under the Statewide Water Quality
Plan and implement those BMPs within five years. Kentucky establishes that a
person engaged in an agricultural operation in a water quality priority protection
region where pollution has been documented “shall be presumed in compliance” if
BMPs have been implemented as required by plan (Ky. Rev. Stat. 224.71-120(9)).
Conducting an agricultural operation in violation of the plan in a manner that
results in water pollution is a violation of law; failure to comply after receipt of
written notice and provision of technical assistance and financial assistance “when
possible” renders a person a “bad actor” subject to a civil penalty not to exceed
$1,000 (Ky. Rev. Stat. 224.71-130).
Kentucky is part of USEPA Region 4 with includes Alabama, Florida, Georgia,
Mississippi, North Carolina, South Carolina, and Tennessee. Region 4 is
developing a regional strategy to include objectives of the U.S. Clean Water
Action Plan and the USEPA/USDA Unified Strategy for AFOs.
83
U.S. Environmental Protection Agency (USEPA), Office of Wastewater Management, 1999,
State Compendium: Programs and Regulatory Activities Related to Animal Feeding Operations, August,
1999, <www.epa.gov/owm/stcpfin.pdf>.
The Management of Manure in Ontario with Respect to Water Quality
55
2.3.11 State Livestock Waste Management Regulations in New York
The following information about New York State was collated as part of the
USEPA’s State Compendium: Programs and Regulatory Activities Related
to AFOs.84
As of 1999, there were approximately 150 large CAFOs (over 1,000 AUs) and
850 medium CAFOs (between 300 to 999 AUs) in New York. No state level
non-NPDES approval is required for construction and operation of an AFO.
A general NPDES permit is required for those operations that fall under USEPA
regulations, and the permit conditions cover waste management. The USEPA
Region that includes New York is currently drafting a regional level AFO program.
Historically, New York did not issue state-level pollutant discharge permits for
CAFOs. This policy was based upon the belief that effluent guidelines could
be achieved without permits through voluntary programs, augmented by
enforcement of existing laws and nuisance laws in severe cases. By 1996, after
a federal court decision regarding a New York CAFO, and in part due to the
changing nature of dairy production toward fewer but larger farms, the New
York Department of Environmental Conservation (NYSDEC) formed the
CAFO Working Group. The premise of the group was that the non-regulatory
approach may no longer be viable. Its role was to examine the legal, regulatory,
policy, environmental, and economic issues to be considered in developing a
more comprehensive approach for CAFOs.85
Based on options brought forward by the CAFO Working Group, NYSDEC
focused on developing a general State Pollutant Discharge Elimination System
(SPDES) permit for CAFOs of over 1,000 animal units and for AFOs of between
300 and 999 AUs that discharge through a man-made conveyance. These size
categories correspond to the existing USEPA regulations. AFOs not covered
under the state permit program would be encouraged to participate in the
voluntary Agricultural Environmental Management (AEM) program,
84
USEPA, Wastewater Management 1999.
New York State Soil and Water Conservation Committee and New York State Department of
Agriculture and Markets, 2000, Guide to Agricultural Environmental Management in New York
State. Specific details about the SPDES permit programs, and access to publications are available
through an associated Web site: <www.dec.state.ny.us/website/dow/cafohome.html>.
85
56
Walkerton Inquiry Commissioned Paper 6
administered by the New York State Department of Agriculture and Markets.
Voluntary programs are detailed in the New York Guide to Agricultural
Environmental Management in New York State. New York Farm Service Agencies,
including the New York State Soil and Water Conservation Committee, the
County Soil and Water Conservation Districts, and Cornell Cooperative
Extension, are responsible for delivering many of the programs related to
CAFOs.
The SPDES permit holders must develop and implement an Agricultural Waste
Management Plan (AWMP). CAFOs must develop their plan within 18 months
after the date of coverage and must implement the plan within 60 months of
coverage. Medium-sized CAFOs must develop the AWMP within 24 months
of the coverage date, and fully implement it within 60 months. The AWMP
must be developed or reviewed by a qualified Agricultural Environmental
Management Planner (AEMP), who must certify that the plan has been
developed in accordance with Natural Resources Conservation Service
guidelines. The New York State Department of Agriculture and Markets trains
and qualifies Agricultural Environmental Management Planners.
The New York City Memorandum of Agreement includes the Watershed
Agriculture Program (WAP),86 intended to improve environmental practices
among watershed farmers. WAP is voluntary, a substitute for regulations, and
is required by the USEPA to avoid filtration orders for New York City’s water
supply. The goal of WAP is to develop and implement comprehensive farm
management plans for each farm in the watershed. Because dairy farms are the
most common, phosphorus and pathogens are the pollutants of concern. WAP
suggests common BMPs, including stormwater management and improved
manure storage. The required goal of WAP is to document a farmer participation
rate of over 95%. As well, an ongoing monitoring program has been established
to determine BMP effectiveness.87
A review of the New York City Watershed Memorandum of Agreement
recommended that lands within the watershed that are enroled in the USDA
Conservation Reserve Program (CRP) be prioritized based on frequency of
flooding, vegetation type, and whether the landowner will voluntarily exclude
livestock from riparian zones. It also recommended that where prioritization
was not possible, rental and cost-share incentives offered by the CRP be increased
86
87
U.S. NRC, 1999.
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
57
to retire frequently flooded farmland into riparian forest buffers and to exclude
livestock from streams.88
New York prohibits the direct or indirect discharge of any substance that “shall
cause or contribute to” a condition in violation of water quality standards
(NY Env. Cons. L. 17-0501). New York state law exempts agricultural activities
only from nuisance actions, and subjects the exemption to various exceptions
such as increased activities and activities causing conditions dangerous to life
or health (NY Pub. Health L. 1300-c).89
New York law requires “every owner or occupier of agricultural land” (defined
as 25 or more acres and certain smaller concentrated operations) to apply to
the local soil and water conservation district for a “soil and water conservation
plan for the land” and requires such districts to prepare such plans (NY Soil
and Water Cons. Dist. L. 9(7-a)). These requirements are enforceable; however,
the law does not make the implementation of the required plan enforceable.90
2.4 Regulations and Policies in Europe
Concerns in the European Union (EU) about the effects of livestock waste
disposal have lead to regulations that require producers either to use costly
waste management techniques or to scale back production. In 1991, the EU
Nitrate Directive was enacted as the central water quality regulatory act that
applies to all member countries. This act sets a nitrate concentration of 50 parts
per million (ppm) in surface water, and requires that land applications of manure
not result in an excess (after plant intake) of more than 170 kg of residual
nitrogen per hectare per year. Regions in the EU that do not meet these standards
are declared “vulnerable” and are therefore subject to more stringent policies as
necessary to bring about compliance. The newer policies targeted to vulnerable
regions limit livestock production and expansions for export markets.91
Denmark requires farmers either to meet a given manure-to-land ratio for their
own holdings, or to document that they have spread the excess manure on
neighbouring lands that are in deficit. Both Danish and Dutch farmers must
register their nutrient balance sheets and maintain fertilizer management plans
88
Ibid.
ELI, 1997.
90
Ibid.
91
Beghin and Metcalf, 2000.
89
58
Walkerton Inquiry Commissioned Paper 6
with the government. They face fines if they produce surplus nitrogen. No
operations larger than 15,000 hogs are permitted. Hog farmers are required to
obtain permits and construct hog manure storage facilities that have the capacity
to hold one year of accumulated waste.92
Some of the most severe problems and most drastic regulatory measures have
been felt in the Netherlands. With 15.5 million people, the country is among
the most densely populated in the world.93 Livestock agriculture is an important
Dutch industry and remains an important contributor to Dutch exports. Many
regions have manure surpluses, which occur when more manure is produced
in the region than there is the land capacity to absorb it without exceeding
environmental standards. The options left to producers are to alter livestock
diets to reduce environmental impacts, transport manure to other regions of
the Netherlands, process manure, or export it elsewhere in the EU. In a letter
to parliament, the Minister of Agriculture, Nature Management and Fisheries,
L.J. Brinkhorst, describes the “manure problem” as one of great significance to
society that has been crying out for years for a solution.94
Manure Production Rights (MPRs) are used to regulate phosphate levels in
the Netherlands. A farm’s holdings of MPRs cap the number of animal units
and thus its phosphate levels. MPRs may be sold and bought according to
market prices, although MPR trading is restricted among livestock sectors.
Each transaction is registered, and the government imposes a ‘fee’ in the form
of 25% of the MPRs that are exchanged in each transaction. Farms can trade
MPRs within regions. Between-region trades can occur as long as the MPRs
flow from regions with manure surpluses to those with manure deficits.95
MPRs were initially distributed among farms based on their 1987 production
levels and available land holdings. In 1995, the Dutch government issued an
across-the-board reduction in MPRs by 30% for hog farms, and reduced them
for all livestock herds by 10% in 1998–1999. A minimum 20% further decrease
92
Ibid.
The Netherlands, Ministry of Agriculture, Nature Management and Fisheries, 2001, “Policy theme:
The environment” [online], [cited August 10, 2001], <www.minlnv.nl/international/policy/environ/>.
94
L.J.Brinkhorst and J.P. Pronk, 1999, “Integrated Approach to Manure Problem,” Letter to the
Dutch Parliament, 10 September 1999, <www.minlnv.nl/international/info/parliament/03.htm>.
95
Beghin and Metcalf, 2000.
96
G. Fox and J. Kidon, 2000, [unpublished manuscript].
93
The Management of Manure in Ontario with Respect to Water Quality
59
was planned by 2000, but controversial judicial cases have resulted in limits to
these reductions. However, without the planned reductions in MPRs, the goal
to achieve a balanced manure market by 2002 cannot be met. A balanced
market would have MPR levels that correspond with the available land base,
meaning no net surplus in manure production. The inability to meet the target
is problematic, since the European Commission had found that the country
was in violation of EU nitrogen targets.
In September 1999, the Dutch government approved a proposal for a new
manure policy, to be phased in for all livestock farms to bring Dutch farmers
into compliance with EU directives. Farmers must dispose of livestock waste
according to set maximum animal manure deposits of 170 kg nitrogen per
hectare per year for arable land, 210 kg nitrogen for fodder crops and 300 kg
per year for grassland. Farmers in surplus would be fined according to a levy
of Dfl 20 per kg of phosphate and Dfl 5 per kg of nitrogen. Fines have been
increased to reduce the incidences of surpluses. Individual farmers would be
required to enter into contracts with other landowners to prove that they can
deposit their manure according to these standards. Farmers unable to produce
such contracts would be in violation of the law and could apply for financial
assistance to cease operations. This system will be phased in so the new system
of manure contracts would only be fully operational by 2005. At that time,
the MNRs, pig production rights, and poultry production rights would expire.
The new policy does not differentiate between livestock sectors; it would
apply to all livestock farmers. The proposals are expected to reduce livestock
numbers by 25–30% for pigs, 15–20% for poultry, 25–30% on finishing
farms, and 10% for veal calves. The policy would have a drastic impact on
farm income. For this reason, the Dutch government recognizes that social
and economic support programs should accompany the restructuring of the
livestock sector.
2.5 Regulations and Policies in Canada
Approaches to water quality protection from livestock agriculture in New
Brunswick and Quebec are summarized. Although both approaches have been
designed relatively recently to deal specifically with increasingly concentrated
livestock facilities, they are quite different.
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Walkerton Inquiry Commissioned Paper 6
2.5.1 New Brunswick
New Brunswick’s approach combines voluntary mechanisms provided by manure
management guidelines that were revised in 1997 plus regulatory mechanisms
under the authority of the province’s Clean Water Act and Health Act.96 The New
Brunswick Health Act prevents locating livestock facilities less than 90 m from a
waterway or dwelling, on marshy or swampy land, or in a flood plain.
The Watercourse Setback Act (under the Clean Water Act) allows municipalities to
designate as protected areas those watersheds that serve as municipal water supplies.
Land uses in designated protected areas are subject to regulatory restrictions beyond
the normal provincial environmental and health provisions. For example, the
setback restricts establishment of any new agricultural land use within 75 m of a
watercourse, and allows no agricultural activity, including grazing livestock, within
30 m. Tillage must be managed to prevent surface runoff from entering the
watercourse. Up to 80% of the costs of materials and foregone income within
the 30 m are available from a joint federal-provincial subsidy. As of 1999,
31 watersheds were designated as protected areas in New Brunswick.97
The province’s new manure management guidelines, approved in 1997, replaced
the 1983 Guidelines for Livestock Manure and Waste Management in New
Brunswick.98 The guidelines provide recommended practices and are not
regulations. They do not supersede land-use acts and regulations such as New
Brunswick’s Clean Environment Act, the Clean Water Act, the Health Act, and
the Agricultural Land Protection and Development Act.
The guidelines aim to reduce odour and water contamination from livestock
operations. The use of manure as valuable fertilizer is emphasized through
adoption of management practices that promote removal of nutrients by
cultivated crops. The recommended minimum separation distances are in part
based on hydrogeological information such as groundwater sources, quality,
and quantity; depth to the water table; depth to bedrock; and surface slope.
Manure storage facilities must be designed to avoid contamination of the
ground, and contaminated surface water must be prevented from leaving
the property. Non-earthen manure storage structures (concrete and glass-lined
97
Ibid.
New Brunswick, Department of Agriculture, Fisheries and Aquaculture, Land Development
Branch, 1997, Manure Management Guidelines for New Brunswick (Fredericton, NB), <www.gnb.ca/
afa-apa/20/10/2010005e.htm>.
98
The Management of Manure in Ontario with Respect to Water Quality
61
metal manure storage structures) are to be constructed according to the latest
editions of the National Building Code of Canada and the National Farm Building
Code of Canada. The design and construction of less-costly earthen structures
must minimize potential pollution of surface and groundwater. The guidelines
provide a set of recommendations for earthen structure construction.
The guidelines provide recommendations for the design and construction of solid
manure storages, including minimum capacities of 210 days of manure accumulation
or a greater volume as required to assure that the operator can spread manure on
land at optimal times for maximum nutrient uptake by crops. The guidelines provide
recommendations on the spreading of manure to optimize crop performance while
minimizing water contamination. Requirements for a minimum land-base and
application rates are supplied in tabular form. There are recommendations that
land suitable for spreading manure should be either owned by the operator or
under formal contractual arrangements with neighbouring landowners.
The New Brunswick Clean Water Act requires that manure should not be spread
within 75 m of a private well or drinking water supply, other than that of the
owner. The Motor Vehicle Act legislates that transportation and application of
manure must be carried out so asto prevent spillage on public properties.
2.5.2 Quebec
Quebec enacted its regulations to reduce pollution from agricultural sources in
July 1997. The goal is to minimize environmental impacts of animal agriculture
by providing for leak-proof storage of livestock waste and regulating spreading
activities on cultivated land.99
The regulation is a command-and-control style. It requires farmers to maintain
an agro-environmental fertilization plan and document all manure spreading.
Livestock waste spreading is restricted to growing periods before October 1
and after March 1, and the use of sprinklers and liquid manure cannons was
prohibited after October 1998.
At no time is animal waste accumulating in a livestock raising facility allowed
to come into contact with the soil. Animal waste storage facilities must be leakproof, and the floor must be above the highest level of the water table. Storage
99
Quebec, Environment Quebec, Reduction of Pollution from Agricultural Sources, Regulation
Highlights, [online], [cited July 5, 2001] <www.menv.gouv.qc.ca/sol/agricole-en/>.
62
Walkerton Inquiry Commissioned Paper 6
facilities must be situated so as to prevent infiltration by runoff. Certain solid
manure storage facilities are exempt from leak-proof requirements. These
facilities can only be used where there are smaller livestock populations than
the limits provided by the regulation. Storage facility capacity must allow
accumulated waste for a minimum period of 250 days, and 200 days for facilities
built before 1997. The maximum amount of waste material that can be stored
cannot exceed a facility’s limit or the quantity that can be spread on the land at
the facility’s disposal. Surplus waste must be transported in a closed watertight
container to a manure management organization.
The regulation specifies conditions under which solid manure coming from a
building is exempt from watertight storage requirements. These include
a minimum distance of 300 m from groundwater sources or municipal water
supplies; 150 m from a lake, watercourse, natural marsh, swamp or pond; and
30 m from a ditch. In addition, such facilities must be secure from runoff
infiltration, on a slope of less than 5%, not located in the 20-year floodplain of
a watercourse or lake, and not located on the same site for two consecutive
years. A waterproof covering must cover manure from a group of facilities
comprising 35 or more animal units.
The goal of the agro-environmental fertilization plans is to ensure that livestock
wastes are spread in such a manner as to minimize water pollution. The plans,
which are mandatory, limit spreading by parcel. They must be prepared and
signed by an agrologist who is a member of the Ordre des agronomes du Québec,
a professional technologist who is a member of the Ordre des technologies
professionnels du Québec, or an owner or shareholder in the operation who
has completed an authorized training course. Copies of plans must be retained
for two years after the activities it documents have been completed. Spreading
registers must be maintained, using a downloadable template. All receipts and
shipments of livestock wastes between facilities must be registered.
Owners of livestock facilities have four options for managing livestock waste:
it can be spread on lands belonging to the owner or neighbouring farmers, it
can be sent to a manure management organization, it can be treated by an
authorized establishment, or it can be sent to a storage facility for later spreading
or treatment. The regulation requires that owners and operators enter into and
honour written agreements with those individuals who undertake to use the
livestock waste that cannot be spread on the owners’ own lands. All changes
must be filed with the Minister of Environment, and all parties must retain
copies of the agreements for at least two years.
The Management of Manure in Ontario with Respect to Water Quality
63
Failure to comply with the regulation is subject to fines that depend upon the
nature of the offence, the number of repeat offences and the legal nature of the
offender, as shown in table 2-4.
2.5.3 Ontario
Ontario has not yet seen the specialized regulations and targeted guidelines for
manure management practices and water quality impairment that we have
documented for other jurisdictions. There are no mandatory provincial
regulations that require the completion of a nutrient management plan. Instead,
the province has adopted a series of eight position statements based on the best
available technical expertise and designed to provide clear direction.100 These
statements include
•
•
•
•
•
recommendations on nutrient management planning,
size of agricultural operations,
land ownership,
distance for hauling manure,
manure sale and transfer of ownership,
Table 2-4 Penalty Structure for Infractions of Quebec’s Livestock
Waste Handling Regulation
Nature of Offence
Administrative Offence
Environmental Offence
First offence
$1,000 to $15,000
$2,000 to $20,000
Repeat offence
$4,000 to $40,000
$5,000 to $50,000
First offence
$1,000 to $90,000
$2,000 to $150,000
Repeat offence
$4,000 to $120,000
$5,000 to $500,000
Fines for a Natural Person*
Fines for a Legal Person*
* The difference between a natural and a legal person could be interpreted as the difference between a person and
an incorporated entity. But due to differences between Quebec law and Ontario common law, these differences
may not be exactly analogous.
Source: Quebec, Environment Quebec, Reduction of Pollution from Agricultural Sources, Regulation Highlights
[online], [cited July 5, 2001] <www.menv.gouv.qc.ca/sol/agricole.en/>.
100
Canada, Agriculture and Agri-Food Canada (AA-FC), Ontario, Ministry of Agriculture, Food
and Rural Affairs (OMAFRA), and Ontario Federation of Agriculture (OFA), 1998, Best
Management Practices, Nutrient Management Planning (Toronto, ON: OFA).
64
•
•
•
Walkerton Inquiry Commissioned Paper 6
manure storage capacity (for which the current version recommends a
capacity of 240 days),
manure storage type, and
minimum distances separation.
Since these statements and the associated BMPs form the backbone of the
Ontario manure management policy, they will be more thoroughly reviewed
following this general overview of Ontario regulations and guidelines.
During 2000, the Ontario Ministry of Agriculture, Food and Rural Affairs
(OMAFRA) initiated a process for reviewing agricultural guidelines that govern
the siting of concentrated livestock facilities and the expansion of existing facilities,
with the view to determine whether a new policy is recommended.101 This process
includes the review of manure management practices in Ontario. A Task Force
on Intensive Agricultural Operations was struck to develop options that would
meet the needs of rural residents and the production and environmental needs of
the agricultural sector. Consultations were held throughout Ontario. How other
jurisdictions handle intensive agricultural operations was also reviewed, including
other provinces, several U.S. states, and some countries in Europe. Documents
associated with this process, including the discussion paper and comments, can
be found at the OMAFRA Web site. This section will concern itself specifically
with the existing policies of Ontario.
The 1994 Agricultural Pollution Control Manual outlined the codes and
regulations that are most likely to apply to livestock producers in the province.102
This document is currently under revision, since a number of the regulations
and statutes have been revised since 1994. Current statutes and laws that apply
to manure handling in Ontario, as originally identified in the Agricultural
Pollution Control Manual, are updated and summarized below.
Farming and Food Production Protection Act (1998) In the words of this act, “it is
in the provincial interest that in agricultural areas, agricultural uses and normal
farm practices be promoted and protected in a way that balances the needs of the
agricultural community with provincial health, safety, and environmental
concerns.” This act, administered by OMAFRA, is designed to protect farm
101
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 2001, Discussion Paper
on Intensive Agricultural Operations in Rural Ontario [online], [cited July 2001] <www.gov.on.ca/
OMAFRA/english/agops/discussion.html>.
102
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 1994a, Agricultural
Pollution Control Manual (Toronto, ON: Queen’s Printer).
The Management of Manure in Ontario with Respect to Water Quality
65
operations from nuisance actions. The act states that any person who carries on
an agricultural operation that does not violate land-use control laws, the
Environmental Protection Act, the Pesticides Act, the Health Protection and Promotion
Act, or the Ontario Water Resources Act is not liable in nuisance to any person for
any odour, noise, or dust from the agricultural operation as a result of normal
farming practices. This act, along with the Agricultural Code of Practice, defines a
standard of reasonable practice for resolving nuisance actions.
The Environmental Protection Act (1990) The part of this act that deals with
spills is most likely to affect the agricultural community. A spill is defined as a
discharge into the natural environment from or out of a structure, vehicle, or
other container that is abnormal in quantity or quality in light of the
circumstances of the discharge. However, the exception is that the act does not
apply to animal wastes disposed of in accordance with normal farming practices.
The act requires that the Ministry of Environment be notified immediately
when a spill occurs, and that the owner and person who had control of the
material at the time is required to contain, clean up, and dispose of the pollutant
in a timely manner. Everything must be done to prevent adverse effects of the
spill and to restore the natural environment.
The Ontario Water Resources Act (1990) The Ontario Water Resources Act is
administered by the Ministry of Environment. Its purpose is to preserve the supply
and purity of the natural waters. The act states that any person or municipality that
discharges material of any kind, into any water body or watercourse, that impairs
the quality of that water is guilty of an offence. Any discharge that is not in the
normal course of events must be reported to the Minister of Environment.
The Environmental Assessment Act (1990) The purpose of the Environmental
Assessment Act is to benefit the people of Ontario or of any part thereof by
providing for the protection, conservation, and wise management of the
environment. An environmental assessment, if required to be submitted for a
proposed project, includes the purpose of the undertaking, the rationale for
the undertaking, a consideration of alternatives, a description of environmental
effects, and an evaluation of the advantages and disadvantages. The proponents
pay the costs of the assessment. The Ministry of Environment reviews the
assessment and the process may involve public hearings and appeals.
The Canada Fisheries Act Under the Fisheries Act, no person shall carry on any
activity that results in the harmful alteration, disruption, or destruction of fish
habitat. The Ontario Ministry of Natural Resources administers the act.
66
Walkerton Inquiry Commissioned Paper 6
The Conservation Authorities Act (1990) This act created conservation
authorities to conserve, restore, develop, and manage watersheds. Conservation
authorities may purchase, lease, or expropriate land and control the flow of
surface water and later watercourses.
The Drainage Act (1980) Administered by OMAFRA, this act stipulates that
no person may discharge, deposit, or permit to be discharged into any drainage
works any liquid material other than unpolluted drainage water. Any person
who contravenes this provision is guilty of an offence with a fine of not more
than $1,000.
The Planning Act (1995) This act is administered by the Ministry of Municipal
Affairs to empower municipalities to create zoning bylaws to restrict the use of
the land and regulate the location, type, and dimensions of buildings and
structures. Water management objectives can be incorporated into municipal
planning documents.103
Recently, some municipalities have more aggressively exercised their authority
to implement bylaws and zoning in ways that target livestock facilities and
nutrient management goals. For example, Oxford County adopted a nutrient
management strategy in 1999. The goal of this strategy is to protect groundwater
and surface water supplies in accordance with the requirements of Oxford
County’s Official Plan. Prior to being granted a permit for a new or expanded
livestock facility on an intensive livestock farm, the operator must document
that the following three elements are in place:
•
a nutrient management plan,
•
satisfaction of OMAFRA’s Minimum Distance Separation Formula II
guidelines, and
•
proper containment of agricultural nutrients during storage and storage
capacity for a minimum of 240 days.
Oxford County’s strategy requires that permits be renewed every three years, at
which times the farmer must obtain a third-party review of the nutrient
management plan by OMAFRA or an agricultural consultant.
103
Ontario, Ministry of Environment and Energy (OMEE) and Ontario, Ministry of Natural
Resources (OMNR), 1993, Integrating Water Management Objectives into Municipal Planning
Documents (Toronto, ON: Queen’s Printer).
The Management of Manure in Ontario with Respect to Water Quality
67
The Ontario Building Code Act (1990) This act deals with the issuance of
building permits, the powers and duties of building officials and inspectors. It
is necessary to obtain a building permit for all agricultural construction projects
in Ontario. Manure storages utilizing concrete, wood, or steel components fall
under the definition of farm buildings and require building permits.
In addition to the acts listed above, the following codes apply.
Minimum Distance Separation Guidelines The purpose of this code is to assist
farmers to reduce the potential of their livestock operations to pollute water,
air, and soil. The guidelines for the “rational” use of land in relation to the
livestock industry include:
•
guidelines for assessing the design, location, and manure management
system of new livestock buildings and the renovation or expansion of
existing livestock operations;
•
guidelines for evaluating the design of the manure management system
on established livestock operations;
•
comprehensive manure management plans for all livestock operations;
•
methods to control water pollution caused by livestock watering at streams,
ponds, or lakes; and
•
flexibility in interpretation to cover special cases without being overly
restrictive.
The MDS guidelines are intended to fill the void in the Environmental Protection
Act. The program is voluntary unless municipalities have passed bylaws requiring
permits and compliance. Permit applicants have the right to appeal to municipal
committees of adjustment (which are appointed at the municipal level to hear
appeals to bylaw requirements on a case-by-case basis) if the standards cannot
be met. An increasing number of municipalities (such as Oxford County,
described above) have developed municipal bylaws affecting livestock manure
management.
68
Walkerton Inquiry Commissioned Paper 6
2.5.3.1 Best Management Practices in Ontario
Best management practices (BMPs) are designed to be practical, affordable
approaches to conserving soil, water, and other natural resources in rural areas.
Manure management issues are covered by a variety of BMPs for soil and
nutrient management, as well as livestock and poultry waste management,
which consists of activities relating to the collection, transfer, storage, and land
application of waste materials, plus restriction of livestock access to watercourses.
It is recognized that manure applied at excessive rates, or that leaches or runs
off following applications, can damage the environment through:
•
excessive growth of aquatic plants resulting from phosphorus
contamination of surface water,
•
contamination of water with disease-causing organisms,
•
excessive nitrate levels in surface or groundwater,
•
poisoning of fish and other aquatic organisms from ammonia toxicity,
•
oxygen depletion of water from the addition of organic matter, and
•
physical and biological damage from organic material.
BMPs have been developed for manure handling in the barn, long-term storage,
and land application. There are recommendations about the transfer of manure
from the barn to the storage facility. In addition to the BMPs, regulations and
guidelines may apply that determine the appropriate siting and setbacks
(minimum distance separation) for barns and storages. The general framework
is presented in OMAFRA’s Guide to Agricultural Land Use.104 The advocated
approach to manure management is to use the manure as a resource that can
help reduce input costs for crop production and optimize crop production and
quality, while protecting soil and water resources.105
The framework that guides nutrient management on farms stresses that farmers
who practice good nutrient management can save time and money by:
104
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 1995a, Guide to
Agricultural Land Use (Toronto, ON: Queen’s Printer).
105
Canada, AA-FC, OMAFRA, and OFA, 1998.
The Management of Manure in Ontario with Respect to Water Quality
69
•
purchasing and applying only what is needed;
•
making better use of on-farm nutrients;
•
identifying opportunities for using lower-cost alternative sources of
nutrients, e.g., manure from a neighbouring farm, sewage sludge, or other
forms of commercial fertilizers;
•
considering more efficient fertilizer application practices; and
•
using rotation, cover crops, residue management, and sound soil
management practices to conserve the nutrients in the soil.
When meeting crop nutrient requirements, farmers are reminded in the BMPs
that:
•
final yields are not determined by fertility alone. They must also consider
soil management, climate, plant population, timing, pest and weed
management, and variety selection.
•
some high-value crops have unique fertility requirements for quality.
•
some legume crops provide some nitrogen for crops in following years, so
they must include an estimate of the amount available to those crops in
the overall nutrient management plan. (Legumes have bacteria in their
roots which convert gaseous nitrogen into ammonium.)
•
it may not be desirable to supply all of a crop’s requirements from organic
sources (manures, sludges, legumes, etc.) as some nutrients may be
oversupplied.
•
they need to know fertility levels and crop requirements in order to apply
appropriate rates.
•
timing is everything – if a crop can access nutrients when needed, quality
and yields are higher.
•
the maximum yield that can be obtained is usually not the most profitable
yield.
70
Walkerton Inquiry Commissioned Paper 6
Farmers are advised by the BMPs to test for nutrient levels and follow the
recommended rates whether the testing is for soil fertility, soil pH, soil nitrate
levels, plant tissue content, or nutrient content of manure or other organic
wastes. The BMPs suggest that the best way to estimate the fertility of the soil
is to use a reliable soil test. They point out that if too little nutrient is added the
yield will suffer; if too much is added, time and money are wasted and there is
a risk of polluting the environment. Nonetheless, it is pointed out that nutrients
are applied to meet the crop’s annual needs and to quickly raise the soil test
into the range where no further additions of nutrients are required (high range).
Fertilizer recommendation is constrained only for soils testing in the high range
or above, so that soil test levels should not change.
Farmers should test their manure every time the manure storage area is emptied,
because the quantity of nutrients and the ratio of nitrogen, phosphorus, and
potassium in manure varies greatly from farm to farm, depending on the diet
of the animals and the amount of bedding and liquid added to the manure.
Table 2-5 summarizes the BMPs for applying nutrients. Farmers are advised
not to provide all nutrients for a crop with manure, because it is not likely that
manure will release its nutrients at the right balance and time, nor is it likely
that all manure has the correct composition to meet crop requirements.
For nitrogen, the amount of nitrate-nitrogen present in the soil at planting or
side-dress time can indicate a soil’s capacity to supply nitrogen. At present the
soil nitrate-nitrogen test is available only for corn (maize) and barley. The results
of soil nitrate-nitrogen tests from variable fields should be interpreted with caution.
Table 2-5 Summary of General BMPs for Applying Nutrients to Crops
Purpose
Practice
For Production and Profit
Apply exactly what crops need when they need it, maximize the benefit of
nutrients by reducing losses, and apply where the nutrients will be used most
efficiently.
For Practicality
Rotation may use nutrients not taken up by previous crop.
For Protection of the
Environment
If the crop’ s needs are met by applying nutrients in the right amount at the right
time, there is no detriment to the environment.
Source: Canada, Agriculture and Agri-Food Canada (AA-FC), Ontario, Ministry of Agriculture, Food and Rural Affairs
(OMAFRA), and Ontario Federation of Agriculture (OFA), 1996, Best Management Practices, Livestock and Poultry
Waste Management (Toronto, ON: OFA; Canada, AA-FC et al.).
The Management of Manure in Ontario with Respect to Water Quality
71
The nitrate-nitrogen levels can vary widely within some fields because of
differences in past management, soil texture, organic matter content, drainage,
or slope. In many fields it is impractical, if not impossible, to sample and fertilize
different areas separately. The use of the soil nitrate-nitrogen test in such fields
has not proven satisfactory.
Because of the specific issues around ammoniacal-nitrogen and nitrate in water,
farmers are expected to consider the following factors when applying nitrogen:
•
account for nitrogen available from all sources: soil, crop residues, manures,
fertilizers, and carryover.
•
where practical, soil-test for nitrate-nitrogen to determine crop
requirements.
•
when crop requirements are based on yield goals, set goals that are
achievable in most years.
•
apply most of the nitrogen near the time when the crop is growing most
rapidly.
•
avoid applying large amounts of material containing nitrogen in the late
summer, fall, or winter. (Nitrogen can run off when it is applied to frozen
ground and leaching or denitrification can be excessive if it is applied
when no crop uptake is occurring.)
•
on soils likely to have high nitrate levels, consider planting cover crops
during periods when a commercial crop is not being grown.
•
incorporate within 24 hours.
•
nitrate is mobile and, if not quickly used by the crop, may be lost to the
air or groundwater.
•
it is recommended that no more than 75% of the crop needs for nitrogen
come from manure.
•
it is advantageous to include some nitrogen from mineral fertilizers, for
the following reasons:
72
Walkerton Inquiry Commissioned Paper 6
–
–
–
nitrogen release from organic materials is dependent on the weather.
In cool, damp seasons, the crop may not receive enough nitrogen
from organic sources for optimum growth and yield.
manure application is often uneven, so parts of the field may receive
insufficient manure to meet crop requirements. A blanket application
of mineral N fertilizer helps to increase overall yields by ensuring all
the field has received sufficient nitrogen.
reducing the N application rate from manure also reduces the amount
of phosphorus being applied to rates closer to crop renewal or crop
requirements.
For phosphorus, BMPs aim to
•
•
•
reduce soil erosion,
incorporate manure to reduce the impact of any runoff, and
halt the application of manure where the soil already tests excessive.
2.5.3.2 Key statements from OMAFRA publications
The following subsections highlight key statements from various publications
that provide substance to the approach advocated. Where possible, the
appropriate Web site address is provided.
2.5.3.3 Siting of livestock facilities in relation to land under different usage
Minimum Distance Separation (MDS) is a land-use planning tool to determine
a recommended distance between a livestock facility and another land use.
The objective is to prevent land-use conflicts and minimize nuisance complaints
that arise from incompatible land uses. MDS is primarily a zoning tool that
does not explicitly account for noise and dust or the potential for ground or
surface water contamination.
Ontario’s MDS I guidelines provide minimum distance separation for new
non-agricultural development from existing livestock facilities.106 Ontario’s
106
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 1995b, Minimum Distance,
Separation 1, (MDS I) (Toronto, ON: Queen’s Printer).
The Management of Manure in Ontario with Respect to Water Quality
73
MDS II guidelines provide minimum distance separation for new or expanding
livestock facilities from existing or approved development.107 The differences
between MDS I and MDS II applications are based on whether the proposed
change in land use is due to a non-agricultural development in an area with
existing agricultural operations (MDS I) or on whether the change is due to
proposed changes in livestock operations in the area of an existing or already
approved non-agricultural land-use activity. Thus, the distinctions recognize
rights of prior uses.
2.5.3.4 Manure handling and storage
There are many good reasons to properly store and handle manure and other
organic wastes. Farmers can profit because manure is a resource that will improve
soil and supply nutrients to their crops. Animal and human contact with diseases
and parasites found in wastes can be avoided. Drinking water supplies and fish
habitats will not be contaminated. As well, properly stored manure and
contaminated liquids are more efficient to manage.
Farmers are made aware that potential pollutants from manure include:
•
•
•
•
coliform bacteria and nitrates that can contaminate water supplies;
pathogenic bacteria that can cause disease in humans and livestock in
extreme cases;
phosphorus, which increases algae growth in watercourses, which can use
up oxygen and kill fish; and
manure odours that often bother neighbours.
Manure can pollute air and water in a variety of ways, such as:
•
•
•
107
contaminated liquid can run from storage areas and exercise yards into
surface and groundwater;
manure stored on gravelly soils or shallow, cracked bedrock can pollute
groundwater; and
bacteria and other microorganisms in stored manure can produce gases
when little or no oxygen is present.
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 1995c, Minimum Distance,
Separation II, (MDS II) (Toronto, ON: Queen’s Printer).
74
Walkerton Inquiry Commissioned Paper 6
Options for collecting manure in the barn:
•
BMP requires at least 240 days storage capacity
Types of storage
Liquid Manure Covered Rectangular Storage Advantages include the storage
facility can act as a foundation for a barn, has good odour control, and reduces
the addition of precipitation. Disadvantages include a potential manure gas
hazard, a high cost for installation, and difficulty in agitation.
Covered Circular Storage Advantages include odour control and ease of agitation.
However, this is also a costly system and impossible to expand.
Open Circular Storage Advantages include low cost, usable on all soil types,
easy agitation and easily retrofitted with a cover. Disadvantages include limited
odour control, difficulty in expansion, and precipitation adds to the volume.
Open Earthen Storage This is a low cost, easy-to-expand system. Disadvantages
include poor odour control, a large surface area resulting in a high volume of
precipitation entering, installation dependent on soil type, and difficult
maintenance.
Solid Manure Roofed Rectangular Storage Advantages include a smaller manure
volume because of no added precipitation, and only solid-manure handling
equipment is required. Disadvantages include high cost, the difficulty of keeping
the manure solid enough, the large amounts of bedding required, the possible
deterioration of the roof, and the inability to accommodate extra liquids such
as milkhouse wastes.
Mixed Storage Open Rectangular Storage with Separate Liquid Runoff Advantages
include the ability to handle high volumes of bedding, a lower cost option if
earthen liquid storage is used, and the ability to handle extra liquids such as
milkhouse and parlour wastes. Disadvantages include the requirement for two
manure handling systems, possible high cost if concrete liquid storages are
required, and the difficulty of sizing if a portion of manure from livestock
enters the liquid storage directly.
The Management of Manure in Ontario with Respect to Water Quality
75
Additions of Non-manure Materials to Stored Manure It is important to manage
all liquids. One of the greatest pollution risks comes from liquid manure around
livestock housing facilities. Contaminated liquids other than urine include
livestock housing washwater, runoff from the exercise yard, silo seepage, runoff
from solid manure, milking centre washwater, and livestock watering wastes.
Including bedding with the manure has several benefits:
•
•
•
•
it increases organic matter and improves soil-conditioning capabilities;
it soaks up liquid and reduces loss of nitrogen to the atmosphere;
it increases the carbon-nitrogen ratio and reduces the risk of organic
nitrogen escaping into the air as manure breaks down; and
it reduces the moisture content and allows more aeration which encourages
composting.
Composting manure before application reduces the nutrients immediately
available to crops. When manure is composted, it becomes a stable, humus-like
material. Manure should not be composted on bare soil in open fields. It should
be done on concrete in a roofed structure to prevent excessive leaching of nitrate.
2.5.3.5 Land application
A given field’s suitability for manure application depends on a combination of
topography, soil type, and vegetative cover. Application rates should include
consideration of the total nutrient management requirements for the farm,
according to crop and soil fertility. BMPs suggest the optimal timing of
applications, as summarized in table 2.6. In general, factors to be considered
when spreading manure include:
•
•
•
•
•
•
•
preventing the loss of nutrients in surface runoff;
reducing the loss of nitrogen into the atmosphere;
minimizing soil compaction and problems with soil structure;
eliminating oversupply of nutrients in soil caused by spreading manure
on same ground each year;
preventing leaching of nitrate into groundwater;
reducing pollution of waterways by manure runoff or direct livestock
access;
minimizing odours during spreading;
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Walkerton Inquiry Commissioned Paper 6
Table 2-6 BMPs for Timing of Application
Months
BMP
Watch For
January to March
Manure should be going into storage, not
onto fields. Do not spread manure onto
frozen, bare or snow-covered land. Do not
spread manure on land with a history of
floods or run-off. Apply only in case of
emergency onto grass or winter cover
crops or on areas of high crop residue
where there is no danger of run-off floods.
Runoff can pollute surface water. Use
common sense and apply only on level,
non-sensitive areas but only in
emergencies.
April to May
Apply to land growing annual crops before
seeding. Apply to row crops as a side
dressing after plants come up. Irrigate or
inject manure before planting corn to
minimize soil compaction. Work manure
into soil immediately (same day) after
application to avoid loss of nitrogen. If
application will cause excessive delays to
planting because conditions are too wet,
apply manure to white bean or soybean
fields where yield will not be hurt as much
by planting days.
Wet or surface-dry soil where the risk of
compaction is high. Apply on coarsetextured best-drained fields first. Excessive
application can create a pollution hazard.
Very dry soil with large cracks where liquid
manure can flow into drainage systems. Till
over drains to avoid the problem.
Seedbeds that do not dry quickly because
of heavy surface residue. These soils will
take that much more time to dry following
application of liquid manure. Planting too
soon after heavy manure application. This
can create ammonia toxicity and reduce
germination and seedling growth. Delay
planting to the extent possible. Phosphorus
in manure that is applied to soil surface
after a crop is seeded may not be available
to that crop. A soil test will indicate if
another source of phosphorus is needed.
June and July
Apply to grasslands.
Inject into grassland that will be plowed
later.
Inject liquid manure between rows of
growing corn (June only) with a modified
tanker.
Apply solid and liquid cattle manure lightly
onto hay fields after cuttings.
Apply early enough to avoid tramping regrowth.
Completely or partially compost manure
before applying to reduce odour and break
up clumps.
Do not use manure on orchard
grass/alfalfa mixtures. Orchard grass can
crowd out alfalfa if manure is applied at
this time.
Loss of nitrogen if there is no rainfall
within 72 hours. Rain will help manure
soak in. Consider an alternative application
system like injection.
The Management of Manure in Ontario with Respect to Water Quality
77
Table 2-6 BMPs for Timing of Application, cont’d.
Months
BMP
Watch For
August to October
Apply to grassland with no history of runoff and floods. Apply to annual crop lands
that will be planted with winter cover
crops.
Denitrification in cold, wet soils. Apply to
best-drained soils only or to land that will
be seeded to cover crops. Mature crops
that are not growing and do not need
nutrients. Very dry soil with large cracks
where fields have tile drainage system.
Liquid manure may leach into drains very
quickly. Till over drains before applications
to break up deep cracks and pores in soil.
Wet or surface-dry soil with a high risk of
compaction. Apply to best-drained fields
first.
Manure should be going into storage, not
onto fields. Do not spread onto frozen,
bare or snow-covered land. Apply, only in
cases of emergency, on grassland, fields
with high crop residue levels or winter
cover crops where there is no risk of
floods or runoff.
Sources: Canada, AA-FC et al., 1996, 1998.
Runoff. Manure will soak in too slowly on
wet fields. It will run off with excess water.
Compaction. Soils are wet and prone to
compaction at this time of year.
November and
December
•
•
slowing the build-up of nutrients and bacteria in ponds, wells, and other
waterways;
spreading of manure on forage and pasture appropriately to avoid rejection
by animals.
All crops will benefit from soil conditioning from adding manure. Some,
however, make better use of nutrients that are changed to forms available to
plants immediately after incorporation.
•
Corn uses the nutrients in manure best because of its high demand for
nitrogen.
•
Grass hay and pasture respond well to manure because they demand
nitrogen. These crops also reduce soil compaction and risk of surface
runoff.
•
Legumes such as alfalfa, trefoil, and soybeans can benefit from added
phosphorus, potassium, and micro-nutrients if soil tests show low levels;
however nitrogen is wasted.
78
•
Walkerton Inquiry Commissioned Paper 6
Cereals do not use as much nitrogen as grass and corn but still have
significant needs.
Protection of water resources from land application All operations need to consider
the protection of water resources. In addition, there is an increasing use of irrigation
in Ontario. Irrigation, the practice of adding water to moisture-deficient soils,
depends on reliable supplies of fresh, clean water from surface and groundwater
sources. Farmers must be aware of the potential impacts of their irrigation systems
on the quantity and quality of groundwater and surface water.
Cover crops are often recommended to protect soil from erosion and take up
residual nitrogen left in the soil when cash crops are not normally growing.
Green manure crops are short-term cover crops, used particularly after shortseason crops such as peas.
Surface water Runoff causing soil erosion carries particulate and dissolved substances
into surface water. Table 2.7 summarizes the relationships between soil type, land
topography and the potential for surface water contamination from manure
runoff.108 Several BMPs are aimed at preventing surface runoff and erosion:
•
reduced tillage systems, which include no-till (the practice of planting
crops with no primary or secondary tillage separate from the planter
operations), ridge-till (an alternative to no-till, a cultivator forms a ridge
Table 2-7 Potential for Surface Water Contamination from Manure
Runoff
Soil Infiltration Rate (soil texture)
Surface Water Contamination Potential
Topography
water
Topography (Land
(Land Slope)
Slope) within
within 150
150m (500
(500ftft.)
.) Ooff w
ater
<0.5%
0.5–2%
2–5%
>5%
Fast (sand)
VL
VL
VL
L
Moderate (loam)
VL
L
L
M
Slow (clay loam)
L
M
M
H
Very slow (clay)
M
H
H
H
H = high risk, M = moderate risk, L = low risk, VL = very low risk
Sources: Canada, AA-FC et al., 1996, 1998.
108
Canada, AA-FC, OMAFRA, and OFA, 1998.
The Management of Manure in Ontario with Respect to Water Quality
79
in early summer and the next year’s crop is planted directly onto the
ridge), and simplified tillage such as chisel plowing or ‘soil saving.’
•
residue management, leaving at least 30% crop residue on the soil surface
after planting. Residue cover moderates soil temperature and encourages
higher earthworm populations which benefit the soil structure.
•
crop rotations that alternate forage or cereal crops with row crops. The
forage or cereal crops leave less soil exposed over the year, while the row
crops leave the soil exposed for much of the year and return little residue
to the soil.
•
drainage of wet fields. Some soils in Ontario are naturally low lying or
have high water tables and need drainage. Drainage also benefits crops
and adds value to agricultural land. Surface drains remove water in shallow
open ditches but have limited effect on the water table. They are usually
used in fine-textured soil. Subsurface drains (tile drains) remove excess
water from the soil profile. Water moves down to the tile drains by gravity.
•
construct erosion-control structures, e.g., grassed waterways, water and
sediment control basins, and diversion terraces, to manage concentrated
flows of water.
•
use strip cropping and buffer strips. Strip cropping is the practice of
planting alternating strips of row crops with forages or cereal crops.
•
till and plant crops across the slope where possible or use a system of
contour cropping.
Soil erosion due to wind can also impact surface watercourses. The key BMP
here is the formation of windbreaks. Trees are planted in strategic areas on the
farm to act as barriers to the wind.
Groundwater The main approach of BMPs is to carry out good nutrient
management planning. To avoid risk of bacterial contamination of wells and
groundwater, the following guidelines for separation distances are followed:
•
•
15 m (50 ft.) for drilled wells with a steel casing greater than 30 m (100 ft.)
in depth, and
30 m (100 ft.) for all other wells.
80
Walkerton Inquiry Commissioned Paper 6
In fields with shallow soil (<1 m) over bedrock, or if the water table is less than
1 m from the soil surface at the time of manure application, it is recommended
that farmers:
•
•
•
•
schedule nutrients to meet crop needs,
use lower rates,
pre-till to reduce excess percolation, and
monitor carefully following application.
Some fields are naturally slowly draining, and the water table can be found
within the top metre of soil in the spring. BMPs that deal with such soils
recommend that farmers:
•
•
•
•
•
•
•
•
•
•
•
•
install drainage tile and/or surface drains;
grow crops suited to wetter soil conditions or crops that are planted later
in the growing season (e.g., soybeans, winter wheat);
use seed treatment;
use disease-resistant/tolerant crop varieties;
use a reduced tillage system such as ridge tillage, which creates a zone of
drier soil for plant growth;
use tillage carefully to expose soil to the air for evaporation and soil
warming;
use crop rotations;
include deep-rooted crops such as alfalfa, clover etc.;
encourage earthworm population for macropore development by leaving
residue on the soil surface;
use timely tillage and field operations;
minimize the tillage passes to reduce compaction; and
consider planting the area to pasture or trees.
Methods To ensure proper application rates of manure and commercial fertilizers,
farmers are advised to calibrate their nutrient application equipment in
combination with soil and manure testing and nutrient management planning.
To do this calibration, farmers must take into account not only the number of
loads being applied to a field but also the different densities of the manure or
whether the spreader is being filled according to the manufacturer’s specifications.
In addition, they must consider soil compaction that may occur under spreaders,
since this can increase runoff. BMPs that lessen the impact of compaction on
soil structure recommend:
The Management of Manure in Ontario with Respect to Water Quality
•
•
•
•
•
•
•
•
•
81
timely tillage and field operation: stay off wet fields, soil should be at
proper moisture conditions at tillage depth;
good drainage: tile drainage should be installed in fields with variable
drainage;
longer crop rotations that include forages/cereals;
leaving forage crops in for longer than one year;
that tillage equipment lifts and shatters soil (coulter chisel, cultivator) as
opposed to pulverizing and grinding (disk);
alternating tillage depth so tillage pans aren’t created;
limiting the amount of traffic, including tillage across a field;
restricting compaction: create a long narrow “footprint” with tire
arrangement, e.g., radials, large tires, tracks; and
limiting axle loads to less than five tonnes per axle.
Soils shouldn’t be worked in the spring until the soil moisture conditions drop
below the ‘lower plastic limit.’ This is the minimum moisture point at which
soils begin to puddle and the maximum point at which soils remain friable.
•
In spring, manure should be applied before planting the most valuable
crop.
•
In summer, plan to side-dress growing row-crops on cereal stubble or
between cuts of forages. To avoid crop damage, manure should not be
spread on crop foliage.
•
In winter, manure should go into storage. Winter application should only
be considered if the storage is full (all recent livestock operations should
have adequate storage). There is considerable risk of runoff with snowmelt,
and no nutrient demand from crops at this time. The following must be
taken into consideration:
•
manure should not be spread on frozen bare (no cover crop) land;
•
manure should not be spread when it is likely to run off, e.g., if a period
of mild temperatures, rainfall, or wet snow is forecast for the ensuing 48
hours; and
•
manure should be spread on a level field and kept away from watercourses.
Ontario BMPs recommend separation distances between applied manure
and surface water sources based on surface water contamination potentials
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Walkerton Inquiry Commissioned Paper 6
given in table 2-7. Table 2-8 summarizes the recommended distances
by type of application (surface-applied and incorporated) and by
contamination potential. Also as a general rule, the distances recommended
for spreading in other seasons should be doubled when spreading is done
in winter.
Buffer zones and setbacks for watercourses Buffer strips or buffer zones are
permanent borders on field boundaries or along watercourses that help reduce
soil input into streams. Generally, narrower separation distances to watercourses
are acceptable where:
•
•
P levels are lower, and
the risk of erosion and runoff due to soil type, cropping and tillage
practices, slope, and distance to the watercourse is lower.
Contingency planning for manure spills A contingency plan includes the
following:
•
•
a list of emergency telephone numbers;
a map showing surrounding dwellings and land uses;
Table 2-8 Minimum Separation Distances to Water Sources for Surface
Water Contamination Potential from Liquid and Solid
Manure Runoff
Surface Water Contamination
Potential
Separation Distance to Surface Water Sources
metres (ft.)
Surface-applied
Incorporated
liquid
solid
liquid
solid
High
30 (100)
15 (50)
18 (60)
9 (30)
Moderate
23 (75)
11 (37)
14 (45)
7 (22)
Low
15 (50)
8 (25)
9 (30)
4.5 (15)
Very Low
9 (30)
4.5 (15)
9 (30)
4.5 (15)
Note: the above minimum separation distances may be reduced to 9 m or 30 ft. (liquid) and 4.5 m or 15 ft.
(solid) where the following practices are implemented.
Soil conservation techniques (e.g., mulch tillage, strip cropping, forages) are practised AND a minimum 3 m
(10 ft.) wide vegetated buffer strip (measured from top of bank) exists along the perimeter of the surface
water source.
For commercial fertilizers, a minimum separation distance of 3m (10 ft.) composed of a vegetable buffer strip
should be established between the area of application and any water course.
Sources: Canada, AA-FC et al., 1996, 1998.
The Management of Manure in Ontario with Respect to Water Quality
•
•
•
•
83
a list of available emergency equipment and supplies and their locations;
a sketch of the farmstead and immediate surroundings, including
emergency water supplies;
a sketch of the area surrounding the farm, indicating where surface and
subsurface drainage water would flow; and
specific plans outlining the action to be followed in the event of a manure
or fertilizer spill.
One tool to help farmers develop sound manure management practices is the
Environmental Farm Plan developed by the Ontario Farm Environmental
Coalition (OFEC). The Ontario Farm Environmental Coalition recommends
that farmers carry out self-assessment of their activities, identify those that
result in environmental losses, and consider specific actions for reducing impacts
on the environment.109 The program is a voluntary educational program with
limited financial resources to assist farmers in carrying out recommended
actions. While a large number of farmers in Ontario have undertaken selfassessments as part of the Environmental Farm Plan, it is unknown as to the
extent to which these farmers have undertaken activities that would reduce
environmental impacts on their farms.
An electronic decision support system, Nutrient Management 2000 (NMAN
2000), has been developed by OMAFRA and the University of Guelph to help
producers develop good manure management skills. The field application
component has been widely adopted by local municipalities to ensure that the
land area available to a producer for applying manure allows all nutrients to be
applied appropriately. The completion of such a nutrient management plan is
commonly required before new barns can be built.
3
Biophysical Aspects of Manure Management
3.1 Background
Feed and water for livestock are the sources for mineral nutrients, metals, and
pathogenic bacteria that are present in manure. If animals drink contaminated
water, diarrhea can result,110 which modifies the concentration of materials
109
More information about the Ontario Farm Coalition is available at <www.gov.on.ca/OMAFRA/
english/environment/ofec/coalition.htm>. More information on the Environmental Farm Plan is
available at <www.gov.on.ca/OMAFRA/english/environmental/efp/efp/htm>.
110
D. Peer and W. Merritt, 1997, Water quality and pig performance. Factsheet (Guelph, ON: Ontario
Ministry of Agriculture, Food and Rural Affairs).
84
Walkerton Inquiry Commissioned Paper 6
within the manure. Water quality guidelines exist to protect animal health.111
However, other than considering the transmission of pathogens between
animals, there is little information on the impacts of animal manure on water
quality.
Manure management should, and increasingly does, start with the formulation
of the animal diets (figure 3-1). A properly designed diet provides all the
nutrients and roughage required for growth, body maintenance, and
reproductive capacity, while preventing unnecessary excess. Excess nutrients
either pass through the alimentary tract and are excreted in the feces or are
absorbed and then removed from the body, together with metabolic breakdown
products, via the kidneys. In mammals, materials removed from the bloodstream
by the kidneys are excreted along with water as urine. Avian species conserve
water, and waste products separated by the kidneys are voided through the
same opening as undigested feed.
Figure 3-1 The Main Parts of a Manure Management System that are
Relevant to Environmental Contamination by Manure
Constituents
Animal nutrition
Feed
Excretion
Manure transfer
Long-term storage
Short-term storage
Manure transfer and field application
Crop nutrition and
soil structure stabilization
111
Canadian Council of Ministers of the Environment (CCME), 1999, “Canadian water quality
guidelines for the protection of agricultural water uses: Summary table,” Canadian Environmental
Quality Guidelines, 1999 (Winnipeg: CCME).
The Management of Manure in Ontario with Respect to Water Quality
85
The alimentary tracts of animals provide ideal environments for microbial growth,
including species and strains that are parasitic or pathogenic in humans. Part of
the microbial population is voided along with the feces. The fate of these microbes,
as well as that of the nutrients in manure, is considered in this section.
Most farm animals in Ontario spend significant time in confinement or at
least under cover, so that most manure (the mix of urine and feces for mammals
and the droppings of avian species) is deposited in barns or exercise yards.
These locations provide an initial temporary store of the manure. In some
cases, the manure is removed from the point of defecation and transferred into
longer-term storage. Alternatively, it may be moved into short-term storage
within the same area before being moved into longer-term storage. Sometimes,
the manure undergoes treatment as part of long-term storage.
The manure of animals that graze or range freely is deposited directly on the
land. Land application is also the main way to use stored manure. Spreading
on the land is an important way to conserve the nutrients in the manure for
crop production and reduce dependence on mineral fertilizers.
The fixed facilities where manure is deposited or stored can be considered as
distinct potential point sources for the contamination of the environment and
of water resources in particular. Fields where manure is deposited or purposely
spread represent potential non-point or diffuse sources of contamination.
In this section, we consider all aspects of the potential for contamination of
water resources from manure management systems, from feed manipulation
to the production of crops, with a separate section for each component of the
system (figure 3-1). A major section deals with the natural processes responsible
for the movement of contaminants to water resources.
3.2 Potential Contamination and Manure Management Phase
3.2.1 Feed manipulation
The traditional approach of animal nutrition has been to ensure that a given
feed regime supplied sufficient energy and protein to support metabolic energy
and growth demands, and that other production functions (e.g., eggs laid,
milk produced) were optimized. Manure was a waste product of this endeavour.
Nutrients excreted were indicative of an inefficiency, but they could be recycled,
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Walkerton Inquiry Commissioned Paper 6
at least in part, if manure was used to fertilize crops. The main nutrients in
manure that are of concern for crop production are nitrogen (N), phosphorus
(P), potassium (K), and carbon (C). With the exception of K, these same
elements are important for water quality.
The feed provided for farm animals largely determines the potential for the
contamination of water resources in subsequent phases of manure management.
Large variations in the nutrient content of manure can be related to differences
in levels of animal performance, feed intake, type and quality of diet and feed
management, and environment factors affecting water and food intake.112
Environment factors can also alter water and food intake by animals.113
Depending on the type of livestock and their feeding regime, the typical recovery
of feed N in manure has ranged from 72–89%.114 Obviously, the efficiency of
N-utilization could be improved and thereby result in less N in manure. For
example, while corn grain is an energy feedstuff for pigs, it is deficient in several
amino acids needed for growing animals. The main limiting amino acids are
lysine and tryptophan, followed by threonine and isoleucine. Adding soybean
meal to meet the lysine needs results in an excess of other amino acids in the
diet. The excess amino acids are digested and the nitrogen is excreted via the
kidneys. By feeding the synthetic amino acid L-lysine monohydrochloride,
less soybean meal is required and less N enters the manure.
Animals have a much greater requirement for P than do plants. Some 80–85%
of P in corn grain and about 75% in soybean meal is unavailable to nonruminants (e.g., pigs and poultry) because they lack the enzyme phytase which
cleaves the orthophosphate groups from the phytate molecule to release the P
in a more easily digested form. P-needs are met by the addition of monosodium
or dicalcium phosphate. Upwards of 65–75% of the total P in the diet may
then be excreted.
Over the past decade, animal nutrition has focused on nutrient-use efficiency.
Major strides have been made in understanding the impact of feed on the
112
American Society of Agricultural Engineers (ASAE), 1998, ASAE Standards 1998: Standards,
Engineering Practices, and Data, 45th ed., (St. Joseph, MI: ASAE); J.B. Holter and W.E. Urban Jr.,
1992, “Water partitioning and intake prediction in dry and lactating Holstein cows,” Journal of
Dairy Science, 75, p. 1472; H.H. Van Horn, A.C. Wilkie, and W.J. Powers, 1994, “Components of
dairy manure management systems,” Journal of Dairy Science, 77, p. 2008.
113
Holter and Urban, 1992; Van Horn, Wilkie, and Powers, 1994.
114
J. Azevedo and P.R. Stout, 1974, “Farm animal manures: an overview of their role in the
agricultural environment,” Manual (California Agricultural Experiment Station), 44.
The Management of Manure in Ontario with Respect to Water Quality
87
nutrient content of animal excreta. Consequently, the feed industry has been
changing rations and hence modifying the characteristics of manure. Some of
the potential impacts of improving feed management are shown in table 3-1.
Increased efficiency in livestock production through improved feed conversion
(essentially the amount of animal protein formed from a given amount of
plant protein) can reduce the time that the animals are on the farm before
being sent to market, and consequently reduce the amount of manure excreted
per unit weight of meat produced. The impact of this on the total and regional
production of manure is considered further in section 4.
By knowing the nitrogen content of the animal feed, one can predict the quantity
of nitrogen excreted by the principal groups of farm animals.115 The total
Table 3-1 Feed-related Measures Contributing to the Reduction in
Pollution Caused by Animal Production
Changes in feeding regime
Possible reduction in nutrient content (%)
Nitrogen
Phosphorus
20–25
–
5
–
–
25–30
Supplements
Increase use of supplementary amino acids and
related compound combined with reduced levels of
protein in feed.
Enzymes: Cellulase
Phytases
Modified grains: high-available-P corn
25
5
5
10–15
10–15
Phase feeding
15
15
Increased use of highly digestible raw materials
5
5
Growth-promoting substances
Systems
Precise feed formulation to animal needs
Sources: P. Williams, 1993 [personal communication]; C.F.M. de Lange, 1996, “Animal and feed factors
determining N and P excretion with pig manure,” Managing Manure for Dairy and Swine. Towards
Developing a Decision Support System, M.J. Goss, D.P. Stonehouse, and J.C. Giraldez (eds.), (Fair Haven,
NJ: SOS Publications).
115
Kirchmann and Witter, 1992.
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Walkerton Inquiry Commissioned Paper 6
manure-N may be calculated by apportioning the nitrogen in the feed between
the nitrogen assimilated by the animal and that excreted. For example, Charles
developed a model that correlates the feed intake of hens to the numbers of
eggs produced.116 By analysing the feed and calculating the amount eaten, one
can determine the nutrients available and predict egg production. The nutrient
content of the manure is assumed to be the difference between the nutrient
intake and that required for egg production.
In Ontario, hogs may be bred and raised for slaughter at the same unit (farrowto-finish operations) or may be born in a farrowing unit, moved to a separate
nursery unit and thence to a grower-finisher barn (segregated operations). On
average, each sow farrows twice a year and produces 18 market pigs per year.
This family unit excretes a total of 114 kg of N, 23 kg of P, and 70 kg of K.
Approximately 70% of the nutrients are excreted by the grower-finisher animals.
Feed intake can be used to predict the nutrient content of the manure
(figure 3-2). The efficiency of nitrogen utilization by grower-finisher pigs can
be best improved by making the dietary balance of amino acids closer to the
pigs’ required balance. More closely meeting the nutrient requirements during
the various stages of growth (phase feeding) also improves the efficiency. For
Figure 3-2 Model to Predict N- and P-output in Pig Manure from the
Feed Input and That Used for Pig Growth
N and P in feed
No. pigs removed
in each category
Total feed usage
N and P content in bodies of
animals removed (according to
category, type, and lean yield)
Total N and P usage
N and P removed in animals
N and P excreted by pigs
as manure and gases
Source: de Lange, 1996.
116
D.R. Charles, 1984, “A model of egg production,” British Poultry Science, 25, p. 309.
The Management of Manure in Ontario with Respect to Water Quality
89
example, by manipulating the dietary amino acid balance, N-excretion in
manure was reduced by 35% in grower pigs and 20% in finisher pigs without
affecting animal performance.117
The largest improvements in phosphorus utilization by pigs are expected from
phase feeding and improving P-digestibility.118 As stated earlier, much of the P
present in feed grains is in the form of phytates, which are not readily digested
by non-ruminants. Although supplementary-P is commonly included in the
diet of these animals to ensure an adequate supply, an alternative is to add the
enzyme phytase to the diet to break down the phytate. At the University of
Guelph, a genetically modified pig has been developed that secretes the phytase
enzyme in its saliva. It is anticipated that commercial herds of such animals
would not require supplementary-P in their diet. Another approach is the use
of newly developed corn hybrids. These store P in a more available form in the
grain. Feeding these “high-available-P” (HAP) hybrids can also reduce the need
for supplementary-P and reduce the P excreted.
For ruminant animals such as cattle and sheep, the approach to promoting
efficient feed conversion has been to vary the amount of protein and
carbohydrate and improve the degradability (ease with which materials are
broken down in the digestive tract) of components in the feed. This not only
affects the amount of N, P, and K voided in manure, but also the proportion of
N in feces relative to that in urine.
Tamminga concluded that 10–15% of the total N-intake is not utilized because
of inefficiencies in amino acid utilization.119 Microbial fermentation in the
hindgut can result in more N being absorbed across the intestinal wall, thereby
shifting the partitioning of N-excreted between feces and urine toward the
latter. The N in urine is readily converted into mineral-N, whereas the N in
feces is in a form that is converted only slowly to mineral forms.
Fecal excretion of P is primarily due to the unavailability of the phosphorus
source in the diet and its turnover in the animal’s body. P is an important
117
J.K. Tuitoek, L.G. Young, B.J. Kerr, and C.F.M. de Lange, 1993, “Digestible amino acid pattern
for growing finishing pigs fed practical diets,” Journal of Animal Science, 71 (suppl. 1), p. 167.
118
A.W. Jongbloed, 1991, “Developments in the production and composition in manure from
pigs and poultry,” Mest & Milieu in 2000, H.A.C. Verkerk (ed.), (Wageningen, Netherlands: Dienst
Landbouwkundig Onderzoek) (Dutch).
119
S. Tamminga, 1992, “Nutrition management of dairy cows as a contribution to pollution control,”
Journal of Dairy Science, 75, p. 345.
90
Walkerton Inquiry Commissioned Paper 6
constituent of all cells, where it participates in energy-storing and transporting
processes. It is secreted in saliva and bile into the alimentary canal. Efficiency
of P-absorption from feed, about 50%, varies with the feed source, amount of
feed intake, calcium-to-phosphorus ratio, vitamin D status, intake of other
minerals, intestinal pH, and age of the animal.120 The availability of phosphorus
decreases with the increasing complexity of the molecules containing it.121
For dairy cattle, one must consider the partitioning of nutrients into milk, calf,
and metabolic maintenance. The improved genetic potential of dairy cows has
resulted in increased milk production with increased feed intake.122 If digestive
parameters are similar, manure production would be expected to increase along
with feed intake. Morse et al. compared estimates of total manure production,
calculated using milk produced, feed intake, and either manure-N concentrations
or total dietary nitrogen, with actual amounts collected from highly productive
cows.123 They found that the calculated values underestimated those observed by
approximately 25%. Diet digestibility, moisture content, and level of intake
influence the amounts of manure produced. Stress from heat and humidity
increases water consumption, resulting in an increase in urine production.124
Equations developed to predict nutrient requirements for milk production can
be reconfigured to estimate nutrient excretion into manure, using dietary intake,
milk production, and stage of gestation of milking cows.125 To derive
information for the herd, one must also account for the growth of calves and
young heifers and the body retention of nutrients in dry cows.
Metals derived from the diet are also present in some animal manures. Copper
sulphate is used as a feed additive in swine and poultry to promote weight gain
120
D. Morse, H.H. Head, C.J. Wilcox, H.H. Van Horn, C.D. Hissem, and B. Harris, Jr., 1992,
“Effects of concentration of dietary phosphorus on amount and route of excretion,” Journal of
Dairy Science, 75, p. 339.
121
U.S. National Research Council (NRC), 1989, Nutrient Requirements of Dairy Cattle (Washington,
D.C.: National Academy Press).
122
Canada. Agriculture and Agri-Food Canada (AA-FC), 1995, Dairy Animal Improvement Statistics
(Ottawa: Market and Industry Services Branch).
123
D. Morse, R.A. Nordstedt, H.H. Head, and H.H. Van Horn, 1994, “Production and
characteristics of manure from lactating dairy cows in Florida,” Transactions of the American Society
of Agricultural Engineers, 37, p. 275
124
Holter and Urban, 1992; Morse et al., 1994; M.R. Murphy, 1991, “Water metabolism of dairy
cattle,” Journal of Dairy Science, 75, p. 326.
125
U.S. NRC, 1989; J. Cant, 1999, Algorithms in MCLONE4, <www.oac.uoguelph.ca/ManSys/
Software.htm>.
The Management of Manure in Ontario with Respect to Water Quality
91
and feed efficiency.126 Some of the increased feed efficiency is considered to
result from a reduction in disease because of copper sulphate’s fungicidal and
bactericidal properties.127 Supplemental zinc (Zn) for swine and poultry reduces
the excessive accumulation of copper (Cu) in the liver and enhances general
health and growth.128 Generally, Zn is considered a safe mineral supplement,
the animals tolerating high intakes. It is excreted primarily in feces.129 Pigs
utilize Cu with variable efficiency (20 to 40%), depending on its forms in the
feed and animal age. Most excess Cu is eliminated through biliary excretions
and hence into the feces.130
To act as growth promotants, Cu and Zn levels in swine diets are much higher
than the minimum requirements for normal performance (5–25 ppm for Cu
and 50–125 ppm for Zn, depending on the particular class of swine). In Canada,
the federal Feeds Act limits the maximum level of Cu and Zn in the diet to 125
ppm and 500 ppm respectively, but in the United States, higher levels are
common. In some countries, such as the Netherlands, growth-promoting levels
of Cu and Zn are no longer allowed in finisher pig diets due to the impact on
the environment.
Some other plant micronutrients are also added to feed, such as selenium (Se)
and chromium (Cr). The latter may be added to pig feed (in the form of
chromium picolinate) to reduce fat in the carcass.
The amount of microbial production in the hindgut of animals depends on
the availability of fermentable carbohydrates and protein.131 Diets that have
slower rumen degradability of carbohydrates or faster passage rates provide
greater quantities of these materials.
126
B. O’Dell, E.R. Miller, and W.J. Miller, 1979, Literature Review on Copper and Zinc in Poultry,
Swine and Ruminant Nutrition (West Des Moines, IA: National Feed Ingredients Association);
E.R. Miller, X. Lei, and D.E. Ulley, 1991, “Trace elements in animal nutrition,” Micronutrients in
Agriculture, 2nd ed., J.J. Mortvedt, F.R. Cox, L.M. Shuman, and R.M. Welch (eds.), (Madison,
WI: Soil Science Society of America), p. 601.
127
J.R.J. Sorenson, 1979, “Therapeutic uses of copper,” Copper in the Environment. Part II: Health
Effects, J.O. Nriagu (ed.), (New York: John Wiley & Sons), p. 83.
128
I. Bremner, 1979, “Copper toxicity studies using domestic and laboratory animals,” Copper in
the Environment. Part II: Health Effects, J.O. Nriagu (ed.), (New York: John Wiley & Sons), p. 285.
129
Miller, Lei, and Ulley, 1991.
130
Miller, Lei, and Ulley, 1991.
131
E.R. Orskov, C. Frazer, V.C. Mason, and S.O. Mann, 1970, “Influence of starch digestion in
the large intestine of sheep on caecal fermentation, caecal microflora and faecal nitrogen excretion,”
British Journal of Nutrition, 24, p. 671.
92
Walkerton Inquiry Commissioned Paper 6
Pathogenic bacteria can infect animals through contaminated feed and water
supplies.132 Contamination can come from the manure of other herd members
or from other animals such as rodents. Diet, or at least changes in diet, appear
to influence the shedding of E. coli O157:H7.133
Antibiotic drugs are used as feed supplements for poultry, swine, and beef and
dairy cattle to improve the feed conversion to animal growth and production as
well as to prevent and control disease. The antibiotics used, both subtherapeutically
and for treating disease, include penicillin and tetracycline compounds.
Ionophores, a type of antibiotic, depress or inhibit the growth of specific
microorganisms in the rumen of cattle. This selective inhibition alters rumen
processes, including changing the types of volatile fatty acids produced and
decreasing the breakdown of feed protein. The improved animal performance
associated with the use of ionophores results from the increased energy retention
associated with the change from acetic acid to propionic acid production.134
The concern about the subtherapeutic use of antibiotics in animal husbandry
hinges on the fact that some of these drugs are also used to treat humans.
Antibiotic resistance in pathogenic bacteria has been the main focus of attention.
Strains of Clostridium perfringens in manure (both pig and cattle) were found
to have a high resistance to antibiotics. Their spread through the environment
was related to land application of livestock waste.135 Significant amounts of the
ingested antibiotic can also be excreted in an active form.136 There is also evidence
that some antibiotics can increase shedding of E. coli O157:H7.137
132
D.E. Herriott, D.D. Hancock, E.D. Ebel, L.V. Carpenter, D.H. Rice, and T.E. Besser, 1998,
“Association of herd management factors with colonization of dairy cattle by shiga toxin-positive
Escherichia coli O157,” Journal of Food Protection, 61, p. 802; J.A. Shere, K.J. Bartlett, and C.W.
Kaspar, 1998, “Longitudinal study of Escherichia coli O157:H7 dissemination on four dairy farms
in Wisconsin,” Applied and Environmental Microbiology, 64, p. 1390.
133
J.B. Russell, F. Diez-Gonzalez, and G.N. Jarvis, 2000, “Effects of diet shifts on Escherichia coli
in cattle,” Journal of Dairy Science, 83, p. 863.
134
W.G. Bergen, and D.B. Bates, 1984, “Ionophores: Their effect on production efficiency and
mode of action,” Journal of Animal Science, 58, p. 1465.
135
R. Van Stappen, F. Huysman, and W. Verstraete, 1990, “Land application of piggery manure:
The need for adequate expert systems to evaluate and control manuring practices,” Fertilization
and the Environment, R. Merckx, H. Vereecken, and K. Vlassak (eds.), (Leuven, Belgium: Leuven
University Press), p. 264.
136
H. Gamal-El-Din, 1986, “Biogas production from antibiotic-contaminated cow manure,” Biogas,
Technology, Transfer and Diffusion, M.M. El-Halwagi, (ed.), (New York: Elsevier), p. 720.
137
C. Gyles, 2000, “E. coli O157:H7 – Global perspective,” Canadian Cattleman’s Association
(CCA) E. coli O157:H7 Workshop, 27 and 28 Nov. 2000, Calgary, Alberta, p. 9.
The Management of Manure in Ontario with Respect to Water Quality
93
3.2.1.1 Summary
Feed and water for livestock are the sources of the mineral nutrients, metals,
and pathogenic bacteria that are present in manure. Research aimed at improving
feed utilization has, as one consequence, shown how the nutrient loading into
manure can be modified by diet and how the form of N may change with the
partitioning between urinary and fecal excretion. Diet can also affect the
microbial activity in the hindgut of cattle, which could influence the survival
of pathogens. The potential role of antibiotics in the diet (either at therapeutic
or subtherapeutic levels) in the release of pathogens into manure is of
considerable importance. Adding Cu and Zn to animal feed helps improve
feed utilization, but these elements are also excreted in manure.
3.2.2 Excretion
Nutrients, microbes, endocrine-disrupting substances, and metals – all potential
contaminants of water resources – are excreted by animals in their manure.
Nitrogen is an important nutrient for plants and animals. In the form of nitrates
(NO–3) or nitrites (NO2–), it is an important contaminant of drinking water.
Excreted in both feces and urine, nitrogen occurs in many forms ranging from
urea and uric acid to complex cellular constituents. The major form of urineN is urea (uric acid in birds), although up to 35% may be present in other
forms such as allantoin, hippuric acid, and creatinine.138 The relative agronomic
importance of these different forms of N is unknown. Soon after excretion,
urea and uric acid are thought to change rapidly to ammonium nitrogen.
Carbon compounds in feed are broken down during aerobic cell respiration to
provide energy for the animals. However, if such compounds enter a water course
as manure, they generate a large demand for oxygen in the microorganisms that
feed on them (biological oxygen demand or BOD). Swine manure, for example,
generates a very large BOD, ranging between 70,000 and 200,000 mg/L. This
strong demand for oxygen by microorganisms can seriously deplete the amount
in water bodies so that fish die through lack of oxygen.
138
D.C. Whitehead, D.R. Lockyer, and N. Raistrick, 1989, “Volatilization of ammonia from urea
applied to soil: Influence of hippuric acid and other constituents of livestock urine,” Soil Biology &
Biochemistry, 21, p. 803; R.J. Thomas, K.A.B. Logan, A.D. Ironside, and G.R. Bolton, 1988,
“Transformations and fate of sheep urine -N applied to an upland U.K. pasture at different times
during the growing season,” Plant and Soil, 107, p. 173.
94
Walkerton Inquiry Commissioned Paper 6
Little is known about the amount of carbon excreted in relation to its level in
feed. Beauchamp and Voroney estimated that 15–50% of the feed-C is excreted,
depending largely on the kind of feed, livestock, and feed quality
(digestibility).139 The ability of ruminants to break down cellulose and complex
starches in the alimentary tract also means that their manure tends to have a
higher bacterial content than that of non-ruminants.
The risk of contamination of water resources depends, at least in part, on
where the manure is excreted, which depends on whether the animals are
confined or allowed to graze freely.
3.2.2.1 Direct excretion into water resources
In Ontario, an attempt has been made to reduce manure contamination by reducing
the opportunity for animals to defecate directly into rivers and streams. Nonetheless,
many animals are allowed access to flowing water courses to drink. Seasonal
behavioural studies show that animals do not spend extended periods of time in
the water and usually void little urine or feces there (figure 3-3).140 However, this
normal pattern was not always followed, and on one day at each experimental site,
considerably more direct defecation did take place.141 Once voided, bacteria rapidly
become attached to sediment on the stream bed, where they can survive for at least
two months.142 Few are present in the water beyond 50 m from the point of entry.143
Access to streams also allows animals to disturb the sediment, causing the release of
coliforms and other bacteria into the water. These coliforms likely originate from
direct defecation into the stream, in runoff and sediment from the adjacent fields,
or from other sources such as waste treatment plants. Enhanced flow associated
with major rainstorms also moves bacteria downstream.144
139
E.G. Beauchamp and R.P. Voroney, 1993, “Crop carbon distribution to soil with different
cropping and livestock systems,” Journal of Soil and Water Conservation, 49, p. 205.
140
I.J.H. Duncan, E.A. Clark, and K. Maitland, 1998, Livestock Behavior in and near Watercourses
in Ontario: 3 Year Summary, [unpublished report] (Guelph, ON: Animal and Poultry Science and
Plant Agriculture, University of Guelph); H.L. Gary, S.R. Johnson, and S.L. Ponce, 1983, “Cattle
grazing impact on surface water quality in a Colorado front range stream,” Journal of Soil and
Water Conservation, 38, p. 124.
141
Duncan, Clark, and Maitland, 1998.
142
C.M. Davies, J.A.H. Long, M. Donald, and N.J. Ashbolt, 1995, “Survival of fecal microorganisms
in marine and freshwater sediments,” Applied and Environmental Microbiology, 61, p. 1888.
143
H. Whiteley, 1998, Effects of cattle access on bacteria concentrations in streams, [unpublished
report], School of Engineering, University of Guelph.
144
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
95
Alternative methods to keep cattle away from water courses have been
investigated. Fencing is effective but expensive. Providing drinking water in
the field discourages access, as does preventing the animals from forming trails
along stream banks. Providing shade away from streams may also help.145
Constructing low-level crossings at locations normally used by animals to enter
water can prevent collapse of banks and the disturbance of sediment.
3.2.2.2 Excretion in confined or sheltered areas
Ammonia from urine and bird droppings can be released into the atmosphere as a
gas (volatilize) very rapidly after excretion, especially in areas where animals are
confined. More nitrogen is lost by volatilization from within the barn than from
other phases of cattle manure management in the UK.146 Considerable volatilization
of ammonia also occurs from uncovered yards if manure is not removed frequently.
Figure 3-3 Probability that Cows and Calves Will Void Urine or Feces
into a Stream
100
Calves
Cows
Percentage of site-days
80
60
40
Urinate
Urinate
Deficate
Defecate
20
0
<5
5–10
>10
<5
5–10
>10
Probability (%)
Data for 52 site-days over three years from Ontario.
Source: Duncan et al., 1998.
145
I.J.H. Duncan, 1996, Observations of Cattle at Four Sites in Ontario during Summer 1995: Interim
report, [unpublished report] (Guelph, ON: Animal and Poultry Science, University of Guelph).
146
S.C. Jarvis, 1990, “Ammonia volatilization from grazed grassland: Effects of management on
annual losses,” Fertilization and the Environment, R. Merckx, H. Vereecken, and K. Vlassak (eds.),
(Leuven, Belgium: Leuven University Press), p. 297.
96
Walkerton Inquiry Commissioned Paper 6
Up to 23% of the ammonia may come from animal urine.147 The release and
volatilization of ammonia shortly after excretion reduces the final loading of N in
the manure that is subsequently stored and eventually applied to the land.
Once manure is excreted, any pathogens it contains become subject to
environmental stresses that can affect their survival. Some can still reproduce
even though they are outside the body of the host animal. Some, such as
Clostridium perfringens, form spores while others enter a resistant phase in which
they fail to form colonies when attempts are made to culture them.148 Other
potential contaminants of water resources are unlikely to undergo transformation
or growth, but their concentrations in manure may change as the carbon
compounds are used as an energy source by microbes and other organisms.
3.2.2.3 Mineral nutrients and labile carbon compounds
Most of the information on the nutrient content of manure (see table 3-2)
comes from stored rather than freshly excreted material.
Values for BOD concentration in fresh or stored manure are rare, but a few
people have reported values in the range of 20,000 to 30,000 mg/L. Based on
Table 3-2 Characteristics of Different Types of Manure in Ontario
Animal
Category
Range of dry
matter content %
Range of values for nutrient content %
N
P
K
NH4-N
mg/L
Beef cattle
solid
liquid
18–63
1–13
0.45–1.00
0.10–0.50
0.10–0.25
0.02–0.25
0.30–1.00
0.10–0.25
30–1050
700–2100
Dairy cattle
solid
liquid
17–32
1–13
0.55–0.85
0.10–0.40
0.10–0.20
0.02–0.20
0.35–0.60
0.10–0.40
950–1350
650–1900
Pig
solid
liquid
17–51
1–13
0.80–1.75
0.20–0.85
0.40–1.25
0.05–0.35
0.25–1.25
0.10–0.35
1700–4000
1500–5450
Poultry
solid
16–90
0.90–3.20
0.40–1.45
liquid
0.5–12
0.15–0.90
0.02–0.35
Source: C. Brown, 2000 [personal communication], November.
0.35–1.60
0.01–0.35
3221–6450
900–6250
147
B.F. Pain, S. Jarvis, and B. Clements, 1991, “Impact of agricultural practices on soil pollution,”
Outlook on Agriculture, 20, p. 153.
148
Davies et al., 1995.
The Management of Manure in Ontario with Respect to Water Quality
97
the amount of manure per 1,000 kg live animal weight, swine and poultry
contribute more material that generates BOD than do dairy and beef cattle
(table 3-3).
A significant amount of the N lost by volatilization of ammonia immediately
after excretion may be redeposited on fields surrounding the barn, while some
is deposited at a much greater distance. In both cases, no control can be exercised
over the deposition, which is also recognized as a part of acid rain.
The proportion of phosphorus (P) in organic form is greater in solid manure
than in liquid manure. Liquid manure-P can occur as particulates such as
trimagnesium phosphate149 or as soluble components such as orthophosphates
and low-molecular-weight organic phosphorus compounds. Poultry manure
tends to contain the largest concentration of total-P while cattle manure tends
to contain the lowest level.150 Leinweber found that the total-P in dry poultry
manure is less than in liquid swine manure, but the proportion of soluble-P
was greater in poultry manure.151 Swine slurry tends to contain more than
double the amount of P present in cattle slurry.152 The total-P excreted per 100
Table 3-3 Manure Production and Characteristics (per 1,000 kg Live
Animal Weight per Day)
Dairy
Beef
Swine
Poultry
Layer
Broiler
Total
Total manure
manure (feces
(faeces++urine)
urine)(kg)
(kg)
86
58
84
64
85
Total solids (kg)
12
8.5
11
16
22
BOD (kg)
1.6
1.6
3.1
3.3
NA*
* No data available.
Source: after ASAE, 1998.
149
A.W. Fordham and U. Schwertmann, 1977, “Composition and reactions of liquid manure
(gülle), with particular reference to phosphate: II Solid phase components,” Journal of Environmental
Quality, 6, p. 136.
150
C. Tietjen, 1987, “Influence of faecal wastes on soil, plant, surface water and ground water,” Animal
Production and Environmental Health, D. Strauch (ed.), (Amsterdam: Elsevier Science), p. 203.
151
P. Leinweber, 1997, “The concentrations and forms of phosphorus in manures and soils from
the densely populated livestock area in north-west Germany,” [poster], Phosphorus Loss from Soil to
Water, H. Tunney, O.T. Carton, P.C. Brookes, and A.E. Johnston (eds.), (Wallingford UK: CAB
International), p. 425.
152
P. Schweiger, V. Binkele, and R. Traub, 1989, Nitrat im Grundwasser: Erhebungen und
Untersuchungen zum Nitrataustrag in das Grundwasser bei unterschiedlicher Nutzung, Massnahmen
zur Reduzierung und Verhalten von Nitrat im Untergrund (Stuttgart: E. Ulmer).
98
Walkerton Inquiry Commissioned Paper 6
kg live animal weight per year was also greatest for poultry (approximately
12.8 kg/y), followed by pigs (6.2 kg/y), beef cattle (4 kg/y), sheep (2.6 kg/y),
and dairy cattle (2 kg/y).153 The use of phytase or high-available-P corn results
in less P being excreted in pig manure compared with manure from pigs given
a normal diet supplemented with mineral-P (table 3-1).
3.2.2.4 Metals
Manure may contain extra copper (Cu) and zinc (Zn) derived from feed
additives. Evidence from Europe shows significant amounts of cadmium (Cd)
and lead (Pb) in manure (table 3-4). Menzi and Kessler systematically
Table 3-4 Range of Metal Content of Manure from Swiss Farms
Animal
Category
Manure Type
Copper
Zinc
Cadmium
Lead
µg/g dry matter
Cattle
Dairy
Liquid
13–160 (88)
102–395 (267)
<0.08–3.2
1.3–50
Solid
2.5–80 (42)
40–412
0.04–3.1
0.09–15.6
Liquid
36–870
88–938
<0.08–0.80
0.3–14.2
Solid
15–51
48–448
<0.08–0.62
1.3–11.9
Finishers
Liquid
30–376 (774)
337–2490 (1806)
<0.08–0.51
0.9–15.8
Nursery
Liquid
2281
2365
Sows+litter
Liquid
12–1459
146–5832
0.06–1.3
0.34–12.8
Dry sows
Liquid
467
2067
Sheep
Solid
13
104
Layers
Solid (deep litter)
17–486
237–789
0.09–0.42
1.5–4.1
Broilers
Solid
80
320
Beef
Swine
Poultry
Data in brackets are sample values obtained in Ontario. Source: Brown, 2001.
Source: after Menzi and Kessler, 1998.
153
E.P. Taiganides, 1987, “Animal waste management and wastewater treatment,” Animal Production
and Environmental Health, D. Strauch (ed.), ( Amsterdam: Elsevier Science), p. 91.
The Management of Manure in Ontario with Respect to Water Quality
99
investigated the metal content of manure from 1992 to 1997 in Switzerland.154
Their results show considerable variation between the sources and types of
manure (table 3-4). Values from the United Kingdom for metal content lie
within the range of those reported for Switzerland.155 There has been no
systematic analysis of metals in manure from Ontario, and those values, which
have been collected by OMAFRA, suggest that for dairy manure the results are
within the same range as those in European samples. However, Cu values for
swine appear to be well above the range reported for Europe (table 3-4).
Other studies have also reported variability in the metal content of manure similar
to that shown in table 3-4. For example, the total amount of Cu was found to be
similar or even slightly greater in fresh poultry manure compared with fresh liquid
swine manure,156 but on a dry matter basis the percentage was over six times greater
in swine manure.157 More soluble Cu was present in liquid swine manure than in
poultry manure. Cu and Zn are found in equal proportions within swine manure,
but the level of Zn may be more than four times that present per unit of dry matter
Table 3-5 Copper and Zinc Content of Liquid Manure from Different
Animal Categories
Animal Category
Copper
mg/L
Zinc
mg/L
Dairy
Trace (4)
0.1–0.2 (14)
Beef
0–0.1
0.1–0.3
Poultry
0–1.0
0.1–0.3
Swine
0.1–2.2 (29)
0.4–1.8 (50)
Source: Taiganides, 1987.
154
H. Menzi and J. Kessler, 1998, “Heavy metal content of manures in Switzerland,” RAMIRAN
98. Proceedings of the 8th International Conference on the FAO ESCORENA Network on Recycling of
Agricultural, Municipal, and Industrial Residues in Agriculture, Rennes, France, 26–29 May 1998,
J. Martinez and M. Maudet (eds.), (FAO and Cemagref, France), p. 495.
155
B.J. Chambers, F.A. Nicholson, D.R. Soloman, and R.J. Unwin, 1998, “Heavy metal loadings
from animal manures to agricultural land in England and Wales,” RAMIRAN 98. Proceedings of the
8th International Conference on the FAO ESCORENA Network on Recycling of Agricultural, Municipal,
and Industrial Residues in Agriculture, Rennes, France, 26–29 May 1998, J. Martinez and M. Maudet
(eds.), (FAO and Cemagref, France), p. 475.
156
J. Japenga and K. Harmsen, 1990, “Determination of mass balances and ionic balances in animal
manure,” Netherlands Journal of Agricultural Science, 38, p. 353.
157
D. Strauch, 1987, “Hygiene of animal waste management,” Animal Production and Environmental
Health, D. Strauch (ed.), (Amsterdam: Elsevier Science), p. 155; Taiganides, 1987.
100
Walkerton Inquiry Commissioned Paper 6
in poultry and cattle manure. Taiganides also found that cattle in the USA excrete
only trace amounts of these metals (table 3-5).158
As long as dietary levels of Cu and Zn meet the minimum requirements for
animal health, the excretion of these metals in pig manure is not generally
considered an environmental concern. The concentration of Cu in swine manure
from Ontario (table 3-4) would suggest, however, that more than the minimum
requirement is being provided in the feed.
3.2.2.5 Pathogens
Animal manure can be the source of pathogenic organisms such as bacteria
(tables 3-6, 3-7), viruses, protozoa, and helminthic worms.159 The microbial
population in the animal alimentary tract comprises both long-term colonizers
as well as more transitory strains. As a result it is not always easy to identify the
source of a contamination event in the environment. This may influence the
design and selection of appropriate policy instruments to protect water quality
(see section 2.2.2). As well, relatively few pathogenic organisms are found in
manure compared with organisms that have no effect on human health.
Furthermore, pathogens may be present in manure even if the animals present
no symptoms, and a few infected animals can contaminate a whole source of
manure.160 Consequently the more animals on a farm, the greater the likelihood
of pathogens being present in the manure.
Table 3-6 Examples of Pathogenic Bacteria Found in Animal Manure
Manure Type
Bacteria Species
Cattle
Brucella sp., Bacillus anthracis (anthrax), Leptospira
sp., Salmonella sp., Mycobacterium sp., Escherichia
coli, Clostridium perfringens
Swine
Brucella sp.., Leptospira sp., Treponema sp.,
Clostridium tetani, Mycobacterium sp., Escherichia coli,
Salmonella sp.
Poultry
Salmonella sp., Pasteurella sp., Campylobacter sp.
Clostridium sp., Listeria sp., Mycobacterium sp.
Source: after Strauch, 1988.
158
Taiganides, 1987.
Strauch, 1987.
160
D. Strauch, 1988, “Krankheitserreger in Fäkalien und ihre epidemiologische Bedeutung,”
Tierarztliche Praxis, Suppl., 3, p. 21.
159
The Management of Manure in Ontario with Respect to Water Quality
101
Bacteria Very large numbers of bacteria are present in manure, and may total
1010 organisms/mL in liquid manure. The greatest numbers are of fecal coliforms
and streptococci (table 3-8). While bacteria species from these two groups are
always present in manure, Salmonella (another important group of bacterial
pathogens) is present occasionally, mostly in swine and poultry manure. The
prevalence of bacterial pathogens, particularly Salmonella, is thought to be
greater in swine and poultry manure than in cattle manure.161 However, the
numbers may be similar across species when comparisons are made per unit of
dry matter. Due to the greater mobility of bacteria in the liquid phase compared
with the solid phase, liquid manure tends to be more uniformly contaminated
than solid manure.
Table 3-7 Frequency of Detection of Pathogenic Organisms in Cattle
Study Description
Organism
Proportion of Carriers
USA, two national studies and two E. coli O157:H7
studies at state level (Wisconsin and
Washington) of cow feces a
Feces of mature cows: usually
under 1% of the animals but as
high as 5%
Quebec, Canada, feces from
slaughtered cows b
18% of animals
99% of animals
18% of animals
Calves under 24 mths: 2.8%
Salmonella sp.
E. coli
Yersinia sp.
Review of literature, based on fecal Campylobacter
content c
UK, three dairy cow herds
d
Switzerland, 67 larger cow herds
e
0% to 19% of animals
Campylobacter
37% to 81% of animals
VTEC
VTEC (verotoxin
(verotoxin producing
producing E.
E. coli)
coli)
78% of the farms; 43% of the
animals
Campylobacter jejuni
32% of the farms
Campylobacter coli
19% of the farms; 3% of the
animals
Yersinia sp.
22% of the farms; 1.7% of the
animals (infection limited to animals
younger than 8 months)
Sources: a Pell, 1997; b A.A. Mafu, R. Hjiggins, M. Nadeau, and G. Cousineau, 1989, “The incidence of Salmonella,
Campylobacter, and Yersinia enterocolitica in swine carcasses and the slaughterhouse environment,” Journal of
Food Protection, 52, p. 642; c M.J. Blaser, D.N. Taylor, and R.A. Feldman, 1983, “Epidemiology of Campylobacter
jejuni infections,” Epidemiological Reviews, 5, p. 157; d H.I. Atabay, and J.E.L. Corry, 1998, “The isolation and
prevalence of campylobacters from dairy cattle using a variety of methods,” Journal of Applied Microbiology, 84,
p. 733; e A. Busato, D. Hofer, T. Lentze, C. Caillard, and A. Burnens, 1999, “Prevalence and infection risks of zoonotic
enteropathogenic bacteria in Swiss cow-calf farms,” Veterinary Microbiology, 69, p. 251.
161
Strauch, 1987.
102
Walkerton Inquiry Commissioned Paper 6
As pathogenic species or strains are present in far fewer numbers than are the
benign or beneficial ones, the non-pathogenic organisms are commonly used
as indicators of fecal contamination in water resources. Total coliform counts,
numbers of fecal coliforms, and the presence of Escherichia coli (E. coli) are all
used in this way. Some strains of E. coli can cause disease. These strains are
recognized by the presence of particular proteins or polysaccharides on the
surface of the bacteria. One serogroup, the enteropathogenic E. coli (EPEC),
Table 3-8 Examples of Bacterial and Protozoa Numbers in Some
Animal Manure
Manure Type
Fecal Coliforms
3
Fecal Streptococci
Salmonella
Salmonella spp.
spp.
a
Liquid swine
manure
4.3x10 to 1.3x10
b
2.4x103
c
4
9.5x10 to 1.1x10
E. coli
7.2x10 to 4.5x10
Streptococci-D
0 to 1.5x103
(S. infantis)
b
Liquid cattle
manure
2.4x103
9.3x103
0
c
4.5x102 to 1.5x106
E. coli
4.5x102 to 9.5x105
Streptococci-D
0
1.5x107
0
d
Dairy slurry
b
Solid beef manure 2.4x105
a
6
9.3x103
6
0
5
6
1.9x10 to 6.8x10
Solid dairy manure 2.0x105 to 1.0x107
Enterobacteria
e
Fresh cow manure
g
4
6.3x104 to 1.0x107
Enterobacteria
d
f
Protozoa
5
up to 1.0x109
up to 1.0x109
Cryptosporidium
parvum
From 25 to 1.8x104
in healthy animals,
1x1010 in sick
animals
Sources: a A. Unc, 1999, Transport of Faecal Bacteria from Manure through the Vadose Zone, M.Sc. thesis,
University of Guelph, Ontario; b T. Weigel, 1995, Untersuchungen des Infiltrationsverhaltens von
Mikroorganismen in Böden mittels Gruben- und Laborversuchen sowie eines selbst entwickelten Prototyps zur
probennahme ohne Sekundärkontamination, PhD dissertation, University of Hohenheim, Germany; c A. Rüprich,
1994, Felduntersuchungen zum Infiltrationsverömgen und zur Lebensfähigkeit von Fäkalkeimen in Boden nach
Gülledüngung, PhD dissertation, University of Hohenheim, Germany; d Östling and Lindgren, 1991; e J.L.
Mawdsley, R.D. Bargett, R.J. Merry, B.F. Pain, and M.K. Theodorou, 1995, “Pathogens in livestock waste, their
potential for movement through soil and environmental pollution,” Applied Soil Ecology, 2, p. 1; f N.A. Clinton,
R.W. Weaver, L.M. Zibilske, and R.J. Hidalgo, 1979, “Incidence of salmonellae in feedlot manure,” Journal of
Environmental Quality, 8, p. 480; g C.A. Scott, H.V. Smith, and H.A. Gibbs, 1994, “Excretion of Cryptosporidium
parvum oocysts by herd of beef suckler cows,” Veterinary Record, 134, p. 172; K.W. Angus, 1987,
“Cryptosporidiosis in domestic animals and humans,” In Practice, 9, p. 47.
The Management of Manure in Ontario with Respect to Water Quality
103
have given rise to E. coli O157:H7 which contains the genes for ‘Shiga toxin’
or ‘Verotoxin.’ These genes are thought to have been introduced through
infection with bacteriophage (a virus that attacks bacteria), which carried the
genes together with a virulence plasmid. Other disease-causing strains, developed
from the enteroaggregative serogroup of E. coli, have also acquired the same
toxin-forming genes and virulence plasmids. The Verotoxin-forming E. coli
(VTEC) may therefore conform to O157 or non-O157 serogroups.
Not all E. coli with the O157 serotype actually give rise to disease in humans.
However, cattle and other ruminants appear to carry those that do cause illness
(table 3-9). Concentrations of E. coli O157:H7 in cattle feces range from 102
to 105 cfu/g fresh weight. The lower amounts are common in younger animals.
Infection in an individual animal is not continuous; rather, animals experience
a series of reinfections, the frequency declining with age. Furthermore, the
release of E. coli O157:H7 in the feces shows a strong seasonality, being greatest
in July and August. Consequently, the concentration of colony-forming units
in feces is expected to be highly variable with time. Based on the surveillance of
Table 3-9 The Frequency of Detection of E. coli O157 in Animals from
Different Groups
Animal Category
Cattle:
Dairy
Beef feedlot
Cow-calf
Sheep
Pigs
Poultry
Range of reported frequency of detection (%)
0–68
0.3–88
0.7–20
0–31
0–1.4 *
0–1.3
Deer
1.9–9.0
Birds
0.5
Rodents
0–40
Flies
3.3
Horses
1.1
Pet dogs
3.1
* Not E. coli O157:H7.
Source: J. Van Donkersgoed, 2000, “North American primary production perspective,” Canadian Cattleman’s
Association (CCA), E. coli O157:H7 Workshop, 27 and 28 Nov. 2000, Calgary, Alberta, p. 24.
104
Walkerton Inquiry Commissioned Paper 6
beef carcass contamination, the concentration of E. coli O157:H7 in feces may
vary between years as well as between seasons. E. coli O157:H7 has been detected
infrequently in swine or poultry (table 3-9), probably giving less risk of human
infection from these sources.
Other pathogenic bacteria
Leptospira, a waterborne pathogen spread through urine, has been found in
pigs. Survival is enhanced by warm temperatures (19–30°C) and alkaline media.
Yersinia enterocolitica in humans is thought to come mainly from infected pigs.
In Canada, its prevalence appears to be about 20% in finisher pigs.
Campylobacter spp. are commonly found in swine (66% to 95%) and poultry
manure, but are of lesser concern in cattle. The frequency of infection in sheep
tends to be less than in other farm animals.162 C. jejuni has been isolated from
chickens, pigs, and cattle in Ontario. Isolates from chickens and cattle were of
the same serotypes that occur in humans. Most of the pigs that tested positive for
Campylobacter carried a serotype of C. coli that was uncommon in humans.163
Using laboratory-based microcosms (long-term testing units), Thomas et al.
identified that water systems could act as a reservoir for Campylobacter infections.164
To prevent the colonization of poultry chicks by C. jejuni, ‘competitive exclusion’
can be used.165 In this technique, a specific mixture of other intestinal bacteria,
taken from adult birds, is introduced into the cecum of one-day-old chicks.
Listeria monocytogenes can be carried by healthy animals. Shedding of the
bacterium is greater in winter than summer, and it can grow over a wide range
of temperatures from 3–42°C. It is pH tolerant in the range of pH 5.5–9.0.166
162
P.A. Manser and R.W. Dalziel, 1985, “A survey of Campylobacter in animals,” Journal of Hygiene,
(London), 95, p. 15.
163
D.L. Munroe, J.F. Prescott, and J.L. Penner, 1983, “Campylobacter jejuni and Campylobacter coli
serotypes isolated from chickens, cattle, and pigs,” Journal of Clinical Microbiology, 18, p. 877.
164
C. Thomas, D.J. Hill, and M. Mabey, 1999, “Evaluation of the effect of temperature and nutrients
on the survival of Campylobacter spp. in water microcosms,” Journal of Applied Microbiology, 86,
p. 1024.
165
C.A. Phillips, 1995, “Incidence, epidemiology, and prevention of foodborne Campylobacter
species,” Trends in Food Science and Technology, 6, p. 83.
166
A.N. Pell, 1997, “Manure and microbes: Public and animal health problem?” Journal of Dairy
Science, 80, p. 2673.
The Management of Manure in Ontario with Respect to Water Quality
105
Salmonella spp. are known to represent a risk to water supplies.167
Clostridium perfringens is a spore-forming bacterium whose spores are resistant
to environmental stresses including disinfecting agents. It is excreted in the
feces of many animals, but is not present in samples of sludge taken from
septic tanks. Antibiotic-resistant strains of C. perfringens can be used to
distinguish the source of fecal contamination of domestic farm wells; the
presence of C. perfringens together with fecal coliforms indicated that animal
manure was the source.168
Viruses Although viruses are common manure contaminants, information about
their occurrence and longevity in manure is very limited. Many animal viruses
that are likely to be excreted in manure do not cause disease in humans.169
Enteroviruses and adenoviruses in animals are not thought to represent a significant
threat to humans.170 Swine vesicular disease does not appear to pose a threat to
water supplies. Survival outside the host appears to be relatively short. Bovine
parvoviruses do not appear to be related to those that affect humans.
Some viruses, which do give rise to diseases in humans, can be found in large
numbers in manure.171 For example, coronaviruses, which cause diarrhoea in
calves and pigs, are found in manure. Reoviruses excreted by cattle are found
mainly in manure.172
Rotaviruses cause diarrhoea in neonates of humans and a number of other
animals.173 The closeness of the human and swine forms of rotaviruses, together
with the analysis of associated antigens and antibodies, suggest a crossover
167
Ibid.
M.J. Conboy and M.J. Goss, 2001, “Identification of an assemblage of indicator organisms to
assess the timing and source of bacterial contamination in groundwater,” Water, Air, & Soil Pollution,
29, p. 101.
169
Pell, 1997.
170
G.N. Stelma and L.J. McCabe, 1992, “Nonpoint pollution from animal sources and shellfish
sanitation,” Journal of Food Protection, 55, p. 649.
171
P.B. Addis, T. Blaha, B. Crooker, F. Diez, J. Feirtag, S. Goyal, I. Greaves, M. Hathaway, K. Janni,
S. Kirkhorn, R. Moon, D.E. Morse, C. Phillips, J. Reneau, J. Shutske, and S. Wells, 1999, Generic
Environmental Impact Statement on Animal Agriculture: A Summary of the Literature Related to the
Effects of Animal Agriculture on Human Health, University of Minnesota, Minnesota, USA, p. 134.
172
Strauch, 1987.
173
M.K. Estes and J. Cohen, 1989, “Rotavirus gene structure and function,” Microbiological Reviews,
53, p. 165.
168
106
Walkerton Inquiry Commissioned Paper 6
between the two hosts.174 Large numbers of these viruses can be excreted in
feces from infected pigs, with sows being an important source of contamination
of young piglets.175 Bovine rotaviruses may be isolated from cattle manure, but
it is not thought to be common.176
Swine hepatitis E is closely allied to the human form of the virus. The virus is
common in animals of three months or older throughout the mid-western
U.S. states. The human form of the virus is known to be transmitted through
contaminated water.177
Influenza virus is very widespread, and pigs may be a potential reservoir of human
strains. The virus can survive outside the host for a prolonged period. For example,
the infectious avian influenza virus can survive in water for 207 days at 17°C.178
Other animal viruses that can cause disease in humans, such as cowpox and
paravaccinia, are not likely to be found in manure.
Protozoa Protozoan organisms, such as Cryptosporidium parvum, can also cause
severe disease symptoms in humans. In one-third of the diarrheal outbreaks in
1993 to 1994 for which the causal agent was positively identified, C. parvum
and Giardia species were the pathogens involved. River-water samples in the
Ottawa region contained significant numbers of C. parvum oocysts and G.
lamblia cysts, but the origin was likely from sewage treatment plants.179
Cryptosporidium parvum requires the ingestion of between 1 and 100 oocysts to
cause disease in humans. It is considered a threat to surface water supplies, but
174
R.E. Holland, 1990, “Some infectious causes of diarrhea in young farm animals,” Clinical
Microbiology Review, 3, p. 345; N. Santos, R.C.C. Lima, C.M. Nozawa, R.E. Linhares, and V.
Gouvea, 1999, “Detection of porcine rotavirus type G9 and of a mixture of types G1 and G5
associated with Wa-like VP4 specifically: Evidence for natural human-porcinegenetic reassortment,”
Journal of Clinical Microbiology, 37, p. 2734.
175
D.A. Benfield, I. Stotz, R. Moore, and J.P. McAdaragh, 1982, “Shedding of rotavirus in feces of
sows before and after farrowing,” Journal of Clinical Microbiology, 16, p. 186.
176
Pell, 1997.
177
X.J. Meng, R.H. Purcell, P.G. Halbur, J.R. Lehman, D.M. Webb, T.S. Tsareva, J.S. Haynes, B.J.
Thacker, and S.U. Emerson, 1997, “A novel virus in swine is closely related to the human hepatitis
E virus,” Proceedings of the National Academy of Science, 94, p. 9860.
178
I.H. Brown and D.J. Alexander, 1998, “Influenza,” Zoonoses: Biology, Clinical Practice, and Public
Health Control, Lord Soulsby and D.I.H. Simpson (eds.), (Oxford: Oxford University Press), p. 365.
179
C. Chauret, N. Armstrong, J. Fisher, R. Sharma, V.S. Springthorpe, and S.A. Sattar, 1995,
“Cryptosporidium and Giardia in water in the Ottawa (Canada) region: Correlation with microbial
indicators of water quality,” Journal of the American Water Works Association, 87, p. 76.
The Management of Manure in Ontario with Respect to Water Quality
107
recent evidence suggests that the oocysts can move through macropores in the
soil and contaminate shallow groundwater.180 C. parvum cannot be controlled
by chlorination at levels that are safe for use in domestic water supplies.181 Oocysts
of C. parvum have been found in manure from dairy farms and swine farms in
Ontario, although more were present in liquid manure from the swine farms. In
the UK, oocysts were found on 59% of dairy farms and 22.4% of heifers and a
similar number of beef calves were infected.182 Fleming et al. examined the manure
on 60 farms in southwestern Ontario on three occasions over one year.183 C.
parvum was found on 90% of the swine farms. Evidence suggests, however, that
the strain associated with swine does not cause disease in humans.184
Giardia lamblia requires only about 10 cysts to cause disease in a human. It is
the most commonly isolated intestinal parasite. In one study, 3% of young
pigs and 19% of adult animals were infected.185 G. lamblia has been found on
7–67% of swine operations.186 There is evidence that G. lamblia from grazing
cattle contributed to the contamination of a piped domestic water supply in
British Columbia.187 A surface reservoir was the source of the water.
Worms
Ascaris suum, a helminthic worm, appears to be able to pass from pigs to humans,
although evidence from China suggests that the strains that infect pigs are genetically
different from those isolated from humans. Prevalence in swine may be as high as
50%. Up to 2 million eggs can be shed per day by infected animals.
180
D.M. Endale, M.H. Young, D.S. Fisher, J.L. Steiner, K.D. Pennell, and A. Amirtharajah, 2000,
“Subsurface transport of Cryptosporidium from pastures to surface waters: 1. Rationale and site
description,” Annual Meeting Abstracts, ASA, CSSA, SSSA, Minneapolis, Minnesota, November 5–9,
p. 206.
181
Pell, 1997.
182
Ibid.
183
R. Fleming, J. McLelland, D. Alves, D. Hilborn, K. Pintar, and M. MacAlpine, 1997,
Cryptospiridium in Livestock Manure Storages and Surface Waters in Ontario. Final report to Ontario
Federation of Agriculture.
184
M. Olson, 2000, “Transmission and survival of Esherichia coli O157:H7.” Canadian Cattleman’s
Association (CCA) E. coli O157:H7 Workshop, 27 and 28 Nov. 2000, Calgary, Alberta, p. 28.
185
M. E. Olson, C.L. Thorlakson, L. Deselliers, D.W. Morck, and T.A. McAllister, 1997, “Giardia
and Cryptosporidium in Canadian farm animals,” Veterinary Parasitology, 68, p. 375.
186
L. Xiao, R.P. Herd, and G.L. Bowman, 1994, “Prevalence of Cryptosporidium and Giardia infections
on two Ohio pig farms with different management systems,” Veterinary Parasitology, 52, p. 331.
187
J. Issac-Renton, W. Moorehead, and A. Ross, 1995, “Giardia cyst concentrations and infectivity:
Longitudinal community drinking water studies,” Protozoan Parasites and Water, W.B. Betts, D. Casemore,
C. Fricker, H. Smith, and J. Watkins (eds.), (Cambridge: Royal Society of Chemistry, UK).
108
Walkerton Inquiry Commissioned Paper 6
Tenia solium, the human tapeworm, is very uncommon in North America, and
is not thought to pose a risk to water supplies.
3.2.2.6 Endocrine-disrupting substances
Compounds with endocrine-disruption activity alter or affect various hormonal
systems in animals, hence they are also referred to as hormonally active agents.188
Long-term exposure can impair growth, development, and reproduction in fish,
wildlife, and possibly even humans. A number of synthetic compounds, such as
alkylphenols and alkylphenolethoxylates, have endocrine-disruptive activity. They
are variously referred to as environmental estrogens or xenoestrogens. They appear
to mimic the action of natural estrogens, which function to stimulate the growth of
female structures and the development of secondary female characteristics. Relatively
little work has been done to determine the environmental impact of natural
estrogens. However, animal manure is known to contain significant amounts of
these substances, which are produced mainly during reproductive phases.
An assessment of relative estrogenic potency suggests that estradiol-17β ranked
first among a list of naturally occurring estrogens.189 A soybean constituent,
genistein, was given a potency of 1, but the potency of estradiol-17β was 10,000
to 20,000 times greater (table 3-10).
Table 3-10 Relative Potency of Some Endocrine-disruptive Substances
Compound
Relative hormonal potency based on oral dosing
Estradiol-17β
1–2x104
Estrone
6.9x103
Coumesterol
35
Genistein
1
Biochanin-A
188
0.46
L. Ritter, P. Sibley, K. Solomon, and K. Hall, 2002, Sources, Pathways and Relative Risks of
Contaminants in Water, (Toronto: Ontario Ministry of the Attorney General), Walkerton Inquiry
Commissioned Paper 10, Walkerton Inquiry CD-ROM. <www.walkertoninquiry.com>.
189
G.W. Ivie, R.J. Christopher, and C.E. Munger, 1986, “Fate and residues of (4-14C) estradiol-17β
after intramuscular injection into Holstein steer calves,” Journal of Animal Science, 62, p. 681.
The Management of Manure in Ontario with Respect to Water Quality
109
Estrogens are excreted in both urine and feces. Most of the estradiol-17β
injected into steer calves was metabolized before being excreted in feces (57%
of initial material) or urine (42% of initial material).190 However, the
metabolites also had estrogenic activity. Estradiol-17β is excreted by mature
laying hens191 in larger quantities than by non-laying birds (table 3-11).192
Table 3-11 Concentration of Endocrine-disruptive Substances in
Animal Manure
Animal Category
Compound
Concentration (µg/g)
Poultry
a
Layer
Estrogen
1.6
a
Layer
Estrogen
0.81
b
Laying
Estradiol
0.53
da
Broiler
Broiler
Estrogen
0.33
ec
Broiler
Broiler
Estradiol
0.13
fd
Estradiol-17β†
Estradiol-17β
0.01
fd
Estrone†
Estrone†
0.02
hd
Equol†
Equol†
40
Estradiol plus estrone
91
je
Equol†
Equol†
3
Beef
No data
Pigs
Cattle
ib
DDairy
airy
Horse‡
kf
Estradiol-17β
40
† Soluble fraction only, approximate dry-matter content used to obtain concentration
‡ Bedding present
Sources: a C.C. Calvert, L.W. Smith, and T.R. Wrenn, 1978, “Hormonal activity of poultry excreta processed for
livestock feed,” Poultry Science, 57, p. 265; b L.S. Shore, M. Shemesh, and R. Cohen, 1998, “The role of oestrodiol
and oestrone in chicken manure silage in hyperoestrogenism in cattle,” Australian Veterinary Journal, 65, p. 68;
c
Nichols et al., 1997; d Servos et al., 1998; e Burnison et al., 2000; f Busheé et al., 1998.
190
Ibid.
H.F. MacRae, W. Zaharia, and R.H. Common, 1959, “Isolation of crystalline estradiol-17 from
droppings of laying hens,” Poultry Science, 38, p. 318.
192
R.S. Mathur, and R.H. Common, 1969, “A note on the daily urinary excretion of estradiol-17
and estrone by the hen,” Poultry Science, 48, p. 100.
191
110
Walkerton Inquiry Commissioned Paper 6
Estrone excretion was also greater in laying hens, and showed a peak at or
near the day that the first egg was laid.193 Manure from broiler chickens
contained a mixture of estrogen (0.065 µg/g) and the male hormone
testosterone (0.13 µg/g).194
The detection of equol (a metabolite of the plant-derived estrogens daidzein
and formononetin) in swine and dairy manure indicates that some endocrinedisruptive compounds in the diet can contribute to the total loading in manure.
Although relatively large concentrations of equol were found in manure, its
relative potency is considered to be much smaller than that of estradiol-17β.195
3.2.2.7 Summary
Although manure can be excreted directly into streams by grazing animals, this
is not a general phenomenon even in cattle with access to the streams.
Nonetheless, it appears that cattle entry into streams can be limited without
fencing if producers provide shelter and water away from the stream banks.
Data on the amounts of nutrients in animal manure is well documented for
Ontario, but there is little information on the content of metals, pathogens,
endocrine-disruptive compounds, and labile carbon compounds that might be
associated with turbidity in water supplies. There is considerable seasonality in
the release of E. coli O157:H7 into manure, with largest numbers being shed
in July and August.
3.2.3 Initial handling of manure and its short-term storage
Nutrients are conserved best when the manure is deposited on a slatted floor.
Barn ventilation does not strip the ammonia as quickly as when it is deposited
on flat floors. The hydrolysis of urea to ammonia usually takes about two days,
so the length of time the manure remains on the floor before being moved into
storage is one factor affecting the N-loss at this stage.
193
R.S. Mathur, P.A. Anastassiadis, and R.H. Common, 1966, “Urinary excretion of estrone and
of 16-epi-estriol plus 17-epi-estriol by the hen,” Poultry Science, 45, p. 946.
194
L.S. Shore, D. Correll, and P.K. Chakraborty, 1995, “Sources and distribution of testosterone
and estrogen in the Chesapeake Bay Watershed,” Impact of Animal Manure and the Land-Water
Interface, K. Steele (ed.), (Boca Raton, FL: Lewis Publisher, CRC Press), p. 155.
195
B.K. Burnison, T. Neheli, D. Nuttley, A. Hartmann, R. McInnis, A. Jurkovic, K. Terry, T. Ternes,
and M. Servos, 2000, Identification of Estrogenic Substances in Animal and Human Waste, 27th Annual
Aquatic Toxicity Workshop: St. John’s, Newfoundland, Oct. 1–4, 2000.
The Management of Manure in Ontario with Respect to Water Quality
111
The current information available through the Canada Plan Service (CPS) shows
the latest designs for slatted floors and short-term storage (<www.cps.gov.on.ca/
english/plan.htm>). The internal arrangements of pens, ventilation fans, animal
walk alleys, feeders, and waterers are all aimed at keeping the defecation area as
small as possible.
As indicated in section 3.2.2.2, nitrogen concentration in manures differs
between species, feed, and the health of the animals. As well, the type, amount,
and nutrient content of the bedding used and the amount of water added to
manure from drinking water can modify the quality of the manure after
defecation.196 The consistency of manure depends on the type of animal as
well as the feed contents, the water intake, and the amount of water and bedding
mixed with the urine and feces. If the mixture contains less than 12% dry
matter it can usually be handled as a liquid. Manure with a dry matter content
of 10–16% may behave as a semi-solid material, making it difficult to handle.
Above about 14% dry matter, manure generally behaves as a solid material and
is more readily handled.
Surface water courses need to be protected from any runoff that might carry
manure from feedlots and exercise yards. Many modern feedlots have lagoons
to collect any runoff. Of the 229 manure spills recorded by the Ontario Ministry
of the Environment (OMOE) that impacted surface water bodies in the
Southwestern Region of Ontario between 1988 and 1999, 216 related to liquid
manure systems and only three to solid manure systems.197 Manure type was
not recorded for the remaining spills.
3.2.3.1 Nutrients
Nitrogen The transformation of urea and possibly other compounds to
ammonium occurs relatively rapidly, so substantial quantities of ammonia are
lost in swine barns before the manure reaches storage. The loss varied from 5
to 27% of the excreted-N, depending on the duration of the residence period
in the barn, the temperature, and the extent of ventilation.198 Only limited
information is available on the extent of ammonia losses from different manure
management systems and how these losses may be reduced.
196
E.G. Beauchamp, 1983, “Response of corn to nitrogen in preplant and sidedress applications of
liquid dairy cattle manure,” Canadian Journal of Soil Science, 63, p. 377.
197
M. Blackie, 2000, [Personal communication.] Agricultural Impact Specialist, Ontario Ministry
of the Environment, London, Ontario.
112
Walkerton Inquiry Commissioned Paper 6
Carbon It is expected that microbial degradation processes continue following
the voiding of feces and urine, but little is known about the C-transformations
that occur in the short term. For example, liquid manures contain more readily
decomposable C-compounds199 although little is known of differences in
decomposition between liquid and solid manure. These readily decomposable
C-compounds are, presumably, decomposed rapidly in ‘aerobic’ solid manure
systems.
3.2.3.2 Pathogens
Bacteria Barn cleaning is aimed at improving animal welfare. However, alleyflushing systems resulted in an 8-fold higher rate of contamination with E.coli
O157:H7 in dairy animals than was found for other cleaning systems.200
Salmonella agona was found in 84% of swine fecal samples in an open-flush
gutter barn compared with only 9% from pigs on a partly slotted floor.201
Viruses Once outside the host, viruses are unable to multiply. Their survival
depends on the pH of their environment, temperature, and whether they are
adsorbed onto suspended solids or embedded in them.202 Viruses tend to be
inactivated more rapidly in summer than in winter.
3.2.3.3 Summary
Initial handling of the manure of confined animals is a major factor in
determining the final consistency of the manure. Gaseous losses of N can be
significant at this stage. Although carbon compounds are known to undergo
further degradation, little is known about the actual processes.
198
E.G. Beauchamp and D.L. Burton, 1985, Ammonia losses from manures, OMAF Agdex 538.
J.W. Paul, 1991, Corn Yields and Potential for Nitrate Leaching From Manures and Inorganic N
Fertilizer, Ph.D. thesis. University of Guelph, Guelph, Ontario.
200
L.P. Garber, S.J. Wells, L. Schroeder-Tucker, and K. Ferris, 1999, “Factors associated with fecal
shedding of verotoxin-producing Escerichia coli O157 on dairy farms,” Journal of Food Protection,
62, p. 307.
201
P.R. Davies, W.E. Morrow, F.T. Jones, J. Deen, P.J. Fedorka-Cray, and I.T. Harris, 1997,
“Prevalence of Salmonella in finishing swine raised in different production systems in North Carolina,
USA,” Epidemiology and Infection, 119, p. 237.
202
Pell, 1997.
199
The Management of Manure in Ontario with Respect to Water Quality
113
3.2.4 Long-term manure storage
Manure has to be stored for at least part of the year. There are two basic storage
methods:
•
•
keep the manure as dry as possible and store as solid or semi-solid material;
add cleaning water and produce a slurry that can be handled as a liquid.
Implications for engineering and economics and the possibilities for treating the
manure during storage differ markedly between solid and liquid systems.203 Solid
manure can be composted during storage or simply allowed to break down.204
Major changes in the composition and the form of the nutrient fractions can
result.205 Liquid manure can also undergo transformations, particularly resulting
in the release of gaseous products.206 The consistency of liquid manure and the
concentration of nutrients may be further modified on transfer to long-term
storage if washwater from barn or milkhouse cleaning is added.
Various types of liquid storage are popular in Ontario. The majority are open
top storage systems, considered to be the most economical construction.
However, such storage facilities collect rain and snow while allowing free
volatilization of ammonia. Cracks in liquid manure tanks and earthen storages
can lead to groundwater pollution, although this may be small.207 While clean
water infiltrated through unsealed cracks into concrete storages from high water
203
S.F. Barrington and M. Piché, 1992, “Research priorities for the storage of solid dairy manures
in Quebec,” Canadian Agricultural Engineering, 34, p. 393; J.W. Paul, G. Hughes-Games, and B.J.
Zebarth, 1992, Manure Management Workshop, Presented by: Agriculture and Agri-Food Canada,
British Columbia, Ministry of Agriculture, Fisheries and Food, Soils and Engineering Branch, and
Canada-British Columbia Soil Conservation Program.
204
Anon.,1991, “The many views of composting,” The Biocycle Guide to the Art and Science of
Composting, The Staff of Biocycle (eds.), (Emmaus, PA. Jerome Goldstein Press Inc.), p. 270;
G. Guidi and G. Poggio, 1987, “Some effects of compost on soil physical properties,” Compost:
Production, Quality and Use, M. De Bertoldi, M.P. Ferranti, P. L’Hermite, and F. Zucconi, (eds.),
(Pisa, Italy: C.N.R. Institute for Soil Chemistry, Italy), p. 577.
205
C.S. Baldwin, 1981, A Barnyard Manure Story. A Summary of 20 Years Research (Ridgetown,
ON: Soil Section, Ridgetown College of Agricultural Technology); P.O. Ngoddy, J. Haper, R.K.
Robert, G.D. Wells, and F.A. Heidar, 1971, Closed System Waste Management for Livestock
(Washington, D.C.: U.S. Environmental Protection Agency); A. Wild, 1988, “Plant nutrients
in soil: Nitrogen,” Russell’s Soil Conditions and Plant Growth (New York: John Wiley and Sons),
p. 652.
206
L.R. Webber and T.H. Lane, 1969, “The nitrogen problem in the land disposal of liquid manure,”
Cornell University Conference on Agricultural Waste Management, p. 124.
114
Walkerton Inquiry Commissioned Paper 6
tables, the reverse flow was not as great.208 When manure with 10% solids was
in the tank, the leakage was greatly reduced (by more than 10:1). Even though
leakage was slow, the products remained in the soil through which they flowed.209
Once all the soil surrounding a well became contaminated, it was not practicable
to clean it up.
Jofriet has developed new plans for the Ontario Ministry of Agriculture, Food
and Rural Affairs (OMAFRA) which attempt to present best practices in the
design and construction of concrete underground storage.210 Earthen storage,
in areas with shallow bedrock, pervious soils, and shallow water tables, also
endanger water supplies. Some townships require soils engineering to determine
the depth of suitable soil; otherwise artificial liners are needed. Placing a storage
tank above ground is not really a solution because of cost and the difficulty of
filling and agitation.
Particular concern for groundwater quality relates to clay-lined lagoon storage
units located on sandy loam or loamy sand soils with shallow water tables.211
Unless properly constructed using impervious liners, manure liquids can leak
into the subsoil.212 If cracks develop in the walls of the liner after the lagoon has
been emptied, newly added manure can seep out before solids can effect a reseal.
Leaks can also develop if plant roots are allowed to penetrate the liner. Once
manure has leaked out, ammoniacal nitrogen can be nitrified and organic nitrogen
mineralized in the soil, resulting in nitrate that can move to the groundwater.
Problems with liquid manure storage systems contributed 17% of the 229 listed
manure spills mentioned above.213 The failures of storages in terms of cracks or
collapse, although small in number, are of concern. Cracks in storage walls
207
J.G. Rowsell, M.H. Miller, and P.H. Groenevelt, 1985, “Self-sealing of earthened liquid manure
storage ponds: II. Rate and mechanism of sealing,” Journal of Environmental Quality, 14, p. 539;
S.F. Barrington, J. Denis, and N.K. Patni, 1991, “Leakage from two concrete manure tanks,”
Canadian Agricultural Engineering, 32, p. 137.
208
S.F. Barrington., P.J. Jutras, and R.S. Broughton, 1987a, “The sealing of soils by manure.
I. Preliminary investigations,” Canadian Agricultural Engineering, 29, p. 99; S.F. Barrington, P.J. Jutras,
and R.S. Broughton, 1987b, “The sealing of soils by manure. II. Sealing mechanisms,” Canadian
Agricultural Engineering. 29, p. 105.
209
Barrington, Denis, and Patni, 1991.
210
J.C. Jofriet, 1992, Structural Components for Concrete Manure Storage Tanks, Report to OMAF,
Guelph, ON.
211
W.F. Ritter and A.E.M. Chirnside, 1990, “Impact of animal waste lagoons on ground water
quality,” Biological Wastes, 22, p. 39.
212
Barrington, Denis, and Patni, 1991.
213
Blackie, 2000.
The Management of Manure in Ontario with Respect to Water Quality
115
have allowed manure to enter the soil. In the most prominent cases, manure
entered a tile drain and flowed into a watercourse. Both earthen and concrete
storages have been involved, but concrete storages were involved in the most
prominent cases.214 In 1999, Ontario Pork investigated 50 concrete storages
for liquid manure. Eight of these warranted further detailed investigation to
identify whether leakage or spills during transfer of manure to tankers was
responsible for elevated nutrients in the soil close to the tanks.
Fleming et al. reviewed the leakage of manure from storage facilities.215 They
concluded that as long as Ontario guidelines216 were adhered to, significant
leakage was unlikely from either concrete or earthen storage facilities because
of the self-sealing properties of manure. Engineering solutions are available to
prevent problems associated with the transfer of manure from gutters in a barn
to the long-term storage; this has been the cause of some spills.
The size of storage has been an important issue in relation to water quality.
Inadequate storage volume was involved in 34 of 38 manure spills associated
with problems from stored manure in the Southwestern Region of Ontario
between 1988 and 1999. Three times as many reports were related to concrete
storage facilities as to earthen ones.217 Too little long-term storage (e.g., storage
capacity of less than 180 days) also requires the spreading of manure on partly
frozen ground and risks endangering surface water supplies (see Timing of
manure applications, 3.2.6.2).
Solid manure can be stored where it is produced and then transferred to the field.
Such a system rarely allows storage for more than six months. Another possibility
is to regularly transfer the manure to a concrete pad, which may also have side
walls and a roof to keep out snow and rain. If the storage is not roofed, runoff
might develop. This must be addressed, preferably by containment in a liquid
storage. Some farmers still store solid manure in windrows directly on the soil.
These piles can be leached by precipitation, leading to nitrate contamination of
groundwater. Phosphorus can also enter the soil and give rise to elevated
concentrations close to the soil surface.
214
J. Johnson and D. Hilborn, 1999, Interim Recommendations Regarding Tile Drains and Manure
Storage Structures. Infosheet, September, 1999 (Guelph, ON: OMAFRA), <www.gov.on.ca/
OMAFRA/english/livestock/swine/facts/info_interim.htm>.
215
R. Fleming, J. Johnston, and H. Fraser, 1999, Leaking of Liquid Manure Storages: Literature
Review [for Ontario Pork] (Ridgetown,ON: Ridgetown College, University of Guelph).
216
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 1994b, “Earthen Storage
Design and Construction,” Agricultural Pollution Control Manual (Guelph, ON: OMAFRA).
217
Blackie, 2000.
116
3.2.4.1
Walkerton Inquiry Commissioned Paper 6
Fate of manure nutrients during storage
Liquid or slurry manure undergoes anaerobic decomposition unless it is
artificially aerated. Solid manure undergoes mainly aerobic decomposition if
loosely packed or anaerobic decomposition if tightly packed. Aerobic
decomposition of manure organic matter results in the release of CO2 and the
formation of compounds that are more resistant to breakdown by microbes.
When free oxygen is not present, organic matter is converted to low-molecularweight C-compounds, mainly volatile fatty acids (VFA). Methane gas (CH4) is
also produced. VFA are a readily available carbon source for microorganisms
under aerobic conditions.
Nitrogen Addition of straw to poultry manure caused no significant
immobilization of N under anaerobic conditions.218 Loss of N by volatilization
from anaerobic manure was only 1% of initial N-content. During anaerobic
incubation, pH ranged from 5.0 to 6.2, which may be the main reason for
the very small amount of NH3 volatilization losses. Kirchmann and Witter
point out that addition of straw may therefore increase NH3 volatilization
loss if it results in improved aeration and a change from predominantly
anaerobic to aerobic decomposition.219 Using more straw in barns may also
result in greater absorption of urine and a greater capture of N. Depending
on the total amounts of these nutrients, there may be little change in the
C:N ratio of the collected manure.
A clear relationship has been identified between the C:N ratio of a mixture of
cattle manure and straw, and the N-loss occurring during three months’ storage
over the summer. Losses of N from manure with various C:N ratios were 39%
for a C:N of 16, 27% for a C:N of 22, and 10% for a C:N of 33.220
In a review of N-losses from farmyard cattle manure piled on the soil, Kirchmann
found that N-losses by leaching ranged from 4 to 6% from solid manure under
a tarpaulin cover and 10 to 14% from unprotected piles.221 For piles of solid
cattle manure, between 71 and 87% of the N-leaching took place in the first
218
H. Kirchmann and E. Witter, 1989, “Ammonia volatilization during aerobic and anaerobic
manure decomposition,” Plant and Soil, 115, p. 35.
219
Ibid.
220
H. Kirchmann, 1985, “Losses, plant uptake and utilisation of manure nitrogen during a
production cycle,” Acta Agriculturae Scandinavica, Supplementum, 24, p. 77.
221
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
117
20 days, and the concentration of N in the leachate gradually decreased over the
177 days of the investigation.222 Covering the piles with plastic sheeting did not
greatly reduce the total amount of N leached. However, the volume of leachate
due to precipitation was very small during the first 20 days of the study, but
increased with time. Dewes postulated that covering a manure pile would make
it drier, and consequently N-loss by NH3 volatilization would probably be
increased by much more than the N-loss by leaching was decreased.223
For liquid manure, temperatures in outdoor, below-ground, covered storage
tanks in Ontario follow an annual cyclic pattern. Slurry temperature in the
storage tanks ranged from 2 to 25°C.224 For cattle and pig slurry in outdoor
tanks in Denmark, Husted found that a surface crust decreased the rate of
CH4 emission by an order of magnitude.225 The crust was less effective when
slurry temperature was high, apparently because the crust dried and became
porous. Paul also reported greatly increased loss of N as nitrous oxide (N2O)
when there was a surface crust.226
Mineralization of organic-N in slurry during anaerobic decomposition increases
NH4+-N concentrations in the slurry if little NH3 is lost by volatilization. About
73% of the N in anaerobically fermented pig slurry was present as NH4+
compared with 49% in fresh slurry (table 3-12). In anaerobically fermented
cattle slurry, about 58% of the N was present as NH4+.227 Concentrations of
NO3– and nitrite (NO2–) were zero in the pig and cattle slurries (table 3-13).
Patni and Jui also reported that almost no NO–3 and NO–2 occurred in dairy
cattle slurry stored in outdoor tanks, however, NH4+ concentrations increased
by 10 to 20%.228 This slurry had been stored in the barn for six weeks before
222
T. Dewes, 1995, “Nitrogen losses from manure heaps,” Nitrogen Leaching in Ecological Agriculture
(Bicester, Great Britain: A B Academic Publishers), p. 309.
223
Ibid.
224
Patni and Jui, 1987.
225
S. Husted, 1994, “Seasonal variation in methane emission from stored slurry and solid manures,”
Journal of Environmental Quality, 23, p. 58.
226
J. Paul, 1999, “Nitrous oxide emission resulting from animal manure management,” Proceedings
of the International Workshop on Reducing Nitrous Oxide Emissions from Agroecosystems, 3–5 March
1999, Banff, Alberta, R.L. Desjardins, J.C. Keng, and K. Haugen-Kozyra (eds.), (Agriculture and
Agri-Food Canada; Alberta, Agriculture, Food and Rural Development), p. 216.
227
H. Kirchmann and A. Lundvall, 1993, “Relationship between N immobilization and volatile
fatty acids in soil after application of pig and cattle slurry,” Biology of Fertile Soils, 15, p. 161.
228
N.K. Patni and P.Y. Jui, 1991, “Nitrogen concentration variability in dairy-cattle slurry stored
in farm tanks,” Transactions of the American Society of Agricultural Engineers, 34, p. 609.
118
Walkerton Inquiry Commissioned Paper 6
Table 3-12 Characteristics of Fresh and Anaerobically Fermented Pig
Slurry
Characteristics
Fresh
Dry matter (%)
Fermented
10.1
9.8
pH
7.4
7
Total N (g/L)
8.8
9.6
Organic N (g/L)
4.3
2.5
NH4-N (g/L)
4.5
7.0
Fatty acids (g/L)
24.0
37.3
Ratio C:total N
5. 6
5.7
Ratio C:organic N
11.5
21.4
Source: Kirchmann and Lundvall, 1993
Table 3-13 Composition of Animal Dungs: Fresh and After Seven
Months’ Aerobic or Anaerobic Storage
Organic Matter
Org. C
Org. N
Water Soluble
C:N
C
N
mg/g ash-free dry matter
Cattle
Fresh manure
526
28.4
18.6
75.9
6.1
Anaerobic
500
25.2
19.9
3.7
27.3
Aerobic
517
37.9
8.5
3.6
Fresh manure
542
34.2
15.8
117.0
10.3
Anaerobic
551
25.9
21.3
36.7
26.4
Aerobic
499
52.0
9.6
68.1
8.0
Fresh manure
492
61.8
7.9
148.0
7.5
Anaerobic
452
25.2
17.9
20.7
73.2
Aerobic
478
40.8
11.7
60.9
10.1
13.6
Pig
Poultry
Source: Kirchmann and Witter, 1992
The Management of Manure in Ontario with Respect to Water Quality
119
transfer into outdoor storage. In the colder seasons, NH4+ accumulated, while
the warmer seasons resulted in increased rates of NH3 volatilization.229
Distribution of nutrients in storage facilities is an important issue (e.g.,
table 3-14). In this example of under-floor storage, top-loading maintained
larger concentrations of ammonia-N in the upper layer. Using fans to dry the
manure in Barn B conserved nitrogen and reduced the amount that was at
immediate risk of loss by volatilization.230 For liquid manures, mixing before
removal from storage is a normal procedure, but it is a time when odours are
released. Even if mineral nitrogen is uniformly distributed in the storage, this
may not be true for other forms. Concentrations of NH3-N in an earthen
storage receiving dairy manure and milkhouse washwater in New York State
Table 3-14 Characteristics of Poultry Manure Sampled at Different
Depths in Deep-pit Storage
Sample Location
Dry Matter (%)
Total Kjeldahl N
Ammonia-N
pH
% dry weight
Barn A
Top
38.2 ± 3.8
6.1 ± 0.6
3.0 ± 0.8
8.0 ± 0.6
Middle
48.3 ± 9.4
3.5 ± 1.1
1.0 ± 0.3
8.3 ± 0.2
Bottom
46.5 ± 14.2
4.1 ± 1.3
1.2 ± 0.8
8.0 ± 0.7
Top
57.2 ± 18.7
7.9 ± 1.8
1.7 ± 0.8
8.1 ± 0.3
Middle
56.6 ± 33.6
5.3 ± 1.2
1.7 ± 1.3
8.3 ± 0.2
Bottom
82.3 ± 3.4
5.4 ± 0.8
0.8 ± 0.2
7.7 ± 0.7
Top
27.7 ± 0.5
6.1 ± 0.6
3.3 ± 1.0
7.9 ± 0.7
Middle
31.3 ± 3.1
3.6 ± 0.7
0.8 ± 0.1
8.0 ± 0.3
Bottom
32.5 ± 1.5
3.0 ± 0.5
0.7 ± 0.3
8.1 ± 0.2
Barn B
Barn C
Source: Bulley and Lee, 1987.
229
Patni and Jui, 1987.
N.R. Bulley and K.W. Lee, 1987, “Effects of management on the nitrogen content of poultry
manure,” Canadian Agricultural Engineering, 29, p. 81.
230
120
Walkerton Inquiry Commissioned Paper 6
were uniform with depth in the spring. Volatilization from the storage was
probably inhibited by a surface crust layer that was several cm thick. Settling of
solids caused elevated concentrations of total solids, fixed solids, and Kjeldahl-N
at the bottom of the storage.231 Solid manure in open storage tends to lose
NH4+ from the outer layers, which then provide less nitrogen when applied to
the field.232 Mixing solid manure before application is time-consuming for the
operator.
Other mineral nutrients Patni and Jui concluded the following from their
investigation of the mineral content of dairy cattle liquid manure during
anaerobic storage:233
•
The total solids concentration in slurry can decrease during prolonged
storage because of volatilization of some organic materials.
•
In the absence of dilution, concentrations of dry ash and macronutrients
increase due to a decrease of total solids. The dry mineral concentrations
therefore vary as a function of age and the loss of total solids.
•
Concentrations of P, K, Ca, and Mg on a dry-weight basis have a strong
negative correlation with total solids in slurry.
•
About 40 % of slurry ash consists of P, K, Ca, and Mg.
Annual NH3-N loss from manure storages in Denmark have been estimated at
4.2 kg per beef animal and 25.5 kg per dairy animal. Losses from outdoor slurry
storage accounted for 28% of the loss from the beef system and 47% of the loss
from the dairy system.234 These results were obtained using an empirical model,
which also indicated that decreasing the NH3 loss during storage might be of
little benefit because it increased the NH3 loss during the field application phase.
231
R.E. Muck, G.W. Guest, and B.K. Richards, 1984, “Effects of manure storage design on nitrogen
conservation,” Agricultural Wastes, 10, p. 205.
232
R.G. Kachanoski, D.A.J. Barry, D.P. Stonehouse, and E.G. Beauchamp,1997, Nitrogen and
Carbon Transformations in Conventionally Handled Livestock Manure, COESA Report No. RES/
MAN-002/97 prepared for Research Branch, Agriculture and Agri-Food Canada.
233
N.K. Patni and P.Y. Jui, 1984, Changes in Mineral Content of Dairy Cattle Liquid Manure during
Anerobic Storage, Paper No. 84 (Saskatoon, SK: CSAE).
234
N.J. Hutchings, S.G. Sommer, and S.G. Jarvis, 1996, “A model of ammonia volatilization from
a grazing livestock farm,” Atmospheric Environment, 30, p. 589.
The Management of Manure in Ontario with Respect to Water Quality
121
Organic carbon compounds It has been observed that about one-quarter to
one-third of manure-C may be lost as CO2 or CH4 during normal storage
periods.235 Thus C-transformations are obviously occurring, but the processes
are poorly understood. Aeration of the manure is an important factor in
determining carbon loss (table 3-13). Further research is needed to determine
the magnitudes of C losses with different manure storage systems. Importantly,
the loss of carbon at this stage contributes either carbon dioxide (CO2) or
methane (CH4) to the atmosphere, and both are greenhouse gases.
3.2.4.2 Fate of pathogens
The temperature, water content, and aeration status of manure are important for
the survival of potential pathogens (table 3-15). In solid manure stores, pathogens
close to the outside of a pile may be subject to cooler temperatures than are those
near the centre. Consequently, the former may survive, even if those at the centre
do not, and form the source for contamination when spread on the land.236
Bacteria The microbiological population in excreta undergoes considerable
change during storage. Decomposition processes in manure are aerobic if free
Table 3-15 Survival of Potentially Pathogenic Organisms in Manure
Organism
Survival under experimental conditions (days)
Frozen
5° C
30° C
Liquid
manure
Compost
Dried
E. coli
>100
>100
10
100
7
1
Salmonella
>150
150
28
75
14
7
Campylobacter
50
21
7
100
7
1
Giardia
<1
7
7
300
14
1
>300
50
28
>300
28
1
5° C
22° C
37° C
70
56
49
Cryptosporidium
E. coli O157:H7
Sources: G. Wang, T. Zhao, and M.P. Doyle, 1996, “Fate of enterohemorrhagic Escherichia coli O157:H7 in bovine
feces,” Applied and Environmental Microbiology, 62, p. 2567; Olson, 2000.
235
Patni and Jui, 1987; P.J. Vanerp and T.A. Vandiyk, 1992, “Fertilizer value of pig slurries processed
by the Promest procedure,” Fertilizer Research, 32, p. 61.
236
M.D. Sutton, 1983, “Phytopathogens and weed seeds in manure,” Farm Animal Manures in the
Canadian Environment, (Ottawa: National Research Council of Canada Associate Committee on
Scientific Criteria for Environmental Quality), p. 109.
122
Walkerton Inquiry Commissioned Paper 6
oxygen is present and anaerobic if free oxygen is not present. Aerobic
microorganisms produce about 5.5 times more microbial biomass per unit of
organic substrate than do anaerobic microorganisms.
Both cattle slurry and poultry excreta contain a high density of microorganisms.237
The concentration of microorganisms (number per unit volume) in these manures
is about 10¥ greater than in pig slurry. At the beginning of slurry storage, the
population of viable organisms in most microbial groups abruptly declined.238
Denitrifying and sulphate-reducing microbes, together with algae, increased during
this time. Thereafter, the total population multiplied rapidly, becoming five-fold
greater than the initial value after 14 weeks. The increase was mainly attributed to
anaerobic bacteria (proteolytic, ammonific, amylolytic, anaerobic-cellulytic and
anaerobic-nitrogen fixing species). Aerobic heterotrophic bacteria, actinomycetes,
and fungi showed little change.
Viruses Rotaviruses are stable in feces for up to nine months. The longevity of
other viruses can be adversely affected by some bacteria present in manure.
These bacteria have developed various strategies to inactivate viruses, including
the formation of proteases.239
Protozoa Cryptosporidium parvum oocysts were found to survive in liquid
manure storages, despite the high levels of ammonium.240 Giardia appears to
be sensitive to freezing, whereas survival of other pathogens is enhanced.
Temperatures above 30°C reduce survival times for these organisms, with the
possible exception of Giardia (table 3-15). None of the organisms appear to
survive for long in dried manure.
3.2.4.3 Metals
The percentage of Cu in the liquid fraction of swine manure increases slightly
with storage time.241 This is consistent with the loss of carbon and nitrogen in
gaseous form (see section 3.2.2.2).
237
R. Nodar, M.J. Acea, and T. Carballas, 1990, “Microbial composition of poultry excreta,”
Biological Wastes, 33, p. 95.
238
R. Nodar, M.J. Acea, and T. Carballas, 1992, “Poultry slurry microbial population: Composition
and evolution during storage,” Bioresource Technology, 40, p. 29.
239
Pell, 1997.
240
Flemming et al., 1997.
241
Japenga and Harmsen, 1990.
The Management of Manure in Ontario with Respect to Water Quality
123
3.2.4.4 Summary
Liquid manure can be stored in earthen lagoons or concrete storage facilities.
Many of the latter are open-topped. Solid manure may be stored on concrete
pads or in the open.
There is good evidence that if liquid manure stores leak, unless they are located
in very coarse material, the solids in the manure effect a self-sealing and greatly
limit the likelihood of groundwater contamination. Nonetheless, care must be
taken to prevent drying out of the banks or bottoms of earthen lagoons so that
shrinkage cracks do not form and allow obvious leak points to develop. During
construction of concrete storages, care must be taken to ensure that any potential
leak cannot intersect an open tile drain and thereby be diverted into a surface
water source. There has been considerable concern over the integrity of concrete
storages for liquid manure, but the evidence suggests that this is not a widespread
problem in Ontario. Engineering solutions exist to deal with leakage from
pipes that connect the barn with the storage.
Nitrogen is lost in gaseous form from manure storage. Ammonia escaping in
this way can be deposited in surface water resources. Other gases contribute to
the greenhouse gas effect. These losses not only reduce the nutrient value of
manure to the producer, but losses from solid manure take place preferentially
from the surface layers so that there is considerable variability in concentration
with depth in the pile. This variability is not easily rectified since mixing solid
manure before spreading is not readily achieved. Variability of nutrients with
depth occurs in liquid manure, but mixing before spreading is relatively easy.
Bacterial populations can change significantly during storage. Their survival
rates differ, depending on whether the manure is anaerobic or aerobic.
Temperature also affects survival rate of pathogens, but not always in the same
direction. Survival of E. coli O157:H7 is enhanced by cooler temperatures.
The concentration of metals tends to increase during storage because of the
loss of organic matter.
124
Walkerton Inquiry Commissioned Paper 6
3.2.5 Processing and treatment
There may be some risk to water resources from the processing or treatment of
manure on farms. The microorganism content may also change during
treatment. However, the main change is in nutrient content, particularly changes
in nitrogen. These changes can affect the potential risk to water resources when
the products are eventually applied to the land.
3.2.5.1 Composting
Solid manure is being composted (the most common treatment for manures)
on some Ontario farms.242 Composting greatly reduces the bulk volume of the
material, allowing economic transportation over greater distances than with
untreated manure. While the basic requirements for composting are known,
many on-farm operations do not achieve complete stabilization. Various recipes
exist to mix the various carbon- and nitrogen-contributing materials. Table 3-16
shows the range of nutrient contents in compost.
It is commonly believed that up to 50% of the manure-C may be lost during the
composting process. It is not clear what factors are involved in C loss or associated
N-losses or the extent of their effects. Applying raw (fresh or non-composted)
manure to soil and allowing decomposition to occur in the soil adds more carbon,
particularly in compounds that are readily assimilated by microorganisms. This
would be expected to stimulate the microbial population, thereby improving soil
structural development and stability.
Table 3-16 Typical Nutrient Content of Finished Compost from Manure
Nutrient
Content (% dry weight)
Nitrogen
<1–4.5
Potassium
0.5–1
Phosphorus
0.8–1
Calcium
2–3
Magnesium
2–3
Source: British Columbia, Ministry of Agriculture, Food and Fisheries (BCMAFF), 1993, Composting Factsheet
(Victoria: Province of British Columbia), Agdex 537/727.
242
R.J. Fleming, 1993, Impacts of Manure Composting, Water Facts (Toronto: Ontario Ministry of
Agriculture and Food, April).
The Management of Manure in Ontario with Respect to Water Quality
125
Nitrogen The availability of N in composted cattle manure is much lower than
in untreated manure, although release of N appears to continue at a greater
rate for several years.243 N-transformations and ammonia losses occur during
the composting process. It is not clear how composting conditions and the
composting mixture affect these transformations and hence N-availability to
crops. It is believed that significant N-losses may occur if the C:N ratio is too
low (e.g., 20–30) but the optimum is not known. During composting, about
50% of the organic matter, 20–30% of the nitrogen, and 40% of the potassium
content can be lost if manure is windrowed without covering.244
Composting cattle manure in the open resulted in leaching losses of N ranging
from 2% to 10% of the NO–3-N. However, NO–3-N concentrations generally did
not exceed 0.05% of dry matter.245 Composting is often cited as a way of stabilizing
the nitrogen in manure and improving its handling characteristics, but the loss
of N in the process has to be considered against these potential benefits.
Phosphorus and other nutrients The availability of phosphorus and other
nutrients may also change during composting or other processing. Little
information is available to address this issue but the change is probably much
less than that for nitrogen.
Bacteria One benefit of properly controlled composting is that harmful bacteria
and unwanted weed seeds can be killed (table 3-15). However, it is important
to ensure that all the material is subject to temperatures above 55°C, which is
difficult in the absence of forced aeration.246
Viruses Neither bovine enterovirus nor bovine parvovirus survived aerobic
composting for 28 days. Temperature in the pile was maintained at 60°C from
day 3.247
243
Paul, 1991.
H. Vogtmann and J.M. Besson, 1978, “European composting methods: Treatment and use of
farm yard manure and slurry,” Compost Science/Land Utilization, 19, p. 15; N. Lampkin, 1990,
Organic Farming, (Ipswich UK: Farming Press Books)
245
Kirchmann, 1985.
246
R. St. Jean, 1997, On-farm Manure Composting Techniques: Understanding Nitrogen and Carbon
Conservation, Research Report 1.3, COESA Report No. RES/MAN-003/97, Prepared for
Agriculture and Agri-Food Canada, London Research Centre, London, Ontario (Prepared by
Ecologistics Limited, Waterloo, Ontario. <http://res2.agr.gc.ca/london/env_prog/gp/gpres/report/
rep13sum.html>.
247
H.D. Monteith, E.E. Shannon, and J.B. Derbyshire,1986, “The inactivation of bovine enterovirus
and a bovine parvovirus in cattle manure by anaerobic digestion, heat treatment, gamma irradiation,
ensilage and composting,” Journal of Hygiene, 97, p. 175.
244
126
Walkerton Inquiry Commissioned Paper 6
3.2.5.2 Other processing treatments
Other processing treatments commonly address odour formation or gas
production, including the volatilization of ammonia.
Mechanical separation of coarse solids from slurry results in a material that can
be stacked and composted. The liquid can also be treated more readily because
crusts and solid settlement are less of a problem. Such liquids can be aerated in
storage to reduce odour release during land application.
Simply separating solids by passing a slurry through a mesh screen can have a
significant effect on NH3 volatilization. However, for cattle slurry, the solids
need to be separated using a 0.1 mm mesh to reduce ammonia volatilization
by 50%.248 Acidification of the same slurry to pH 5.5 decreased volatilization
by about 85%. Read and Svoboda introduced Cryptosporidium oocysts to the
liquid remaining after solids were separated from cattle slurry.249 The material
was kept at 15°C with minimal aeration. The dissolved oxygen in the liquid
was 0%. The oocysts became non-viable after 4.1 days.
During biogas production (another option for processing manure), much of
the manure-N is converted to the ammonium form and is still available in the
residues from the process. The anaerobic digesters operate either at ambient
temperatures, at which bacteria are not killed, or at elevated temperatures, at
which pathogens do not survive if the minimum temperature is at least 55°C.
However, the efficiency of digesters can be reduced if the manure contains
levels of antibiotics concomitant with therapeutic doses supplied in feed.250
Digestion at temperatures below 40°C may not control pathogens, and 10%
of E. coli and C. jejuni may survive for periods in excess of 50 days.251 However,
248
J.P. Frost, R.J. Stevens, and R.J. Laughlin, 1990, “Effect of separation and acidification of cattle
slurry on ammonia volatilization and on the efficiency of slurry nitrogen for herbage production,”
Journal of Agricultural Science, 115, p. 49.
249
I.A. Read and I.F. Svoboda, 1995, “The effect of aerobic treatment on the survivial of
Cryptosporidium parvum oocysts in cattle slurry,” Protozoan Parasites and Water, W.B. Betts, D.
Casemore, C. Fricker, H. Smith, and J. Watkins (eds.), (Cambridge: Royal Society of Chemistry,
UK).
250
Gamal-El-Din, 1986.
251
T.E. Kearney, M.J. Larkin, J.P. Frost, and P.N. Levett, 1993, “Survival of pathogenic bacteria
during mesophilic digestion of animal waste,” Journal of Applied Bacteriology, 75, p. 215.
The Management of Manure in Ontario with Respect to Water Quality
127
bovine enterovirus and bovine parvovirus survived for only 30 minutes during
thermal anaerobic digestion at 55°C, but at 35°C the enterovirus survived for
13 days.252
Aerobic treatments to reduce manure odours have been much studied.253
These treatments are costly, and N-losses are enhanced by ammonia stripping
or denitrification of nitrate formed by nitrifiers in liquid manures. This loss
of N is agronomically important and represents less sustainable use of
resources.
Patent formulas have been promoted as ways to “stabilize” N in manures during
storage. No scientific evidence shows that such products are effective to any
significant extent for this purpose but there may be some benefits from the
reduction of odour.
3.2.5.3 Summary
Composting is the most widespread process for manure treatment. Composting
stabilizes the remaining nitrogen and improves the manure’s handling
characteristics, but any loss of N in the process has to be considered against
these potential benefits. It is difficult to ensure that all the manure reaches
55°C during the composting process, thereby killing all pathogens.
Other treatments can ensure that manure reaches a sufficiently high temperature
to kill pathogens, but in the past these approaches have been too expensive to
establish on farms of the size typical in Ontario.
3.2.6 Direct deposition and application of manure to the land
In Ontario, some manure reaches the soil by direct deposition from grazing
animals, but the majority is applied as part of the fertilizer requirement for
crops. The various stages in manure management to this point determine the
concentration and form of nutrients reaching the land, as well as the likelihood
that potential microbial contaminants of water will be present.
252
Monteith, Shannon, and Derbyshire, 1986.
128
Walkerton Inquiry Commissioned Paper 6
3.2.6.1 Direct deposition
Grazing animals defecate directly onto soil and vegetation. The runoff or
leaching of contaminants from grazed fields in Ontario has not been
systematically investigated. Runoff water from grazed and ungrazed grass
pastures can contain large numbers of bacteria.254 However, surface runoff does
not constitute an important pathway for water or pathogens from pastures to
enter streams. Most runoff appears to originate close to the stream bank rather
than from the main area of the field.255 Cattle access to water courses can also
contribute to the collapse of banks and entry of soil, nutrients, and pathogens
into the water.256 Once in surface water, the survival of E. coli (ETEC),
Campylobacter jejuni and Yersinia enterocolitica is such that this could be a
persistent site of transmission between animals and humans.257
If drinking water wells in shallow aquifers are poorly maintained or badly located,
they can be impacted by surface runoff. There is evidence of a child being infected
with E. coli O157:H7 from dairy cattle through drinking water from such a well.258
Ammonia volatilization and N-leaching was greater from grassland grazed by
cattle than by sheep.259 Some NH3 volatilized from urine patches is intercepted
by vegetation downwind. This reduces the total gaseous loss of N.
253
E.g., J. Pos, R.G. Bell, and J.B. Robinson, 1971, “Aerobic treatment of liquid and solid poultry
manure,” Livestock Waste Management and Pollution Abatement, Proceedings of the International
Symposium on Livestock Wastes, Columbus, Ohio (St Joseph, MI: American Society of Agricultural
Engineers); T. Al-Kanani, E. Akochi, A.F. Mackenzie, I.A. Ali and S.F. Barrington, 1992a, “Odour
control in liquid hog manure by added amendments and aeration,” Journal of Environmental Quality,
21, p. 704.
254
H. Kirchmann, 1994, “Animal and municipal organic wastes and water quality,” Advances in
Soil Science: Soil Processes and Water Quality, R. Lal and B.A. Stewart (eds.), (Boca Raton, FL: CRC
Press), p. 163.
255
J.C. Buckhouse and C.C. Bohn, 1983, “Response of coliform bacteria concentration to grazing
management: Livestock grazing systems in relation to fecal contamination of rangelands, watersheds,
runoff, non-point source pollution, stream monitoring,” Research in Rangeland Management, Special
Report 682, Agricultural Experiment Station, Oregon State University, p. 1.
256
E.A. Clark, 1998, “Landscape variables affecting livestock impacts on water quality in the humid
temperate zone,” Canadian Journal of Plant Science, 78, p. 181.
257
S.I. Terzieva and G.A. McFeters, 1991, “Survival and injury of Escherichia coli, Campylobacter
jejuni and Yersinia enterocolitica in stream water,” Canadian Journal of Microbiology, 37, p. 785.
258
S.G. Jackson, R.B. Goodbrand, R.P. Johnson, V.G. Odorico, D. Alves, K. Rahn, J.B. Wilson,
M.K. Welch, and R. Khakhria, 1998, “Escherichia coli O157:H7 diarrhoea associated with well
water and infected cattle on an Ontario farm,” Epidemiology and Infection, 120, p. 17.
259
S.C. Jarvis, D.J. Hatch, and D. H. Roberts, 1989a, “The effects of grassland management on
nitrogen losses from grazed swards through ammonia volatilization; the relationship to excretal N
The Management of Manure in Ontario with Respect to Water Quality
129
Evidence from the UK suggests that leaching of NO–3 from grazed pastures is
greater than for cut forage because the urine is excreted in patches. Soil under
these patches can contain large amounts of N that cannot be adsorbed by the
vegetation at a rate sufficient to prevent leaching.260 In this respect, fertilized
pastures do not appear to differ much from pastures comprised of a mixture of
grass and legumes.261 Groundwater loadings of N by leaching from these pastures
are comparable with or even exceed those from arable land.262 However, grazed
land in Ontario is likely used by fewer animals and for a shorter period each year
than that in the UK, so the leaching loss of N is likely to be significantly less.
3.2.6.2 Application to land
On most livestock farms the manure is applied to land, particularly cropped
land.263 Solid manure lends itself only to surface spreading which then requires
a second tillage operation for incorporation. Liquid manure can be spread
from a tanker, applied by irrigation, or injected using hollow tines. After
spreading, liquid manure may also be incorporated by tillage. Application of
liquid manure adds solids plus water, thereby increasing soil water content.
This effect may be sufficient to result in flow through tile drains. Applying
solid manure causes little change in soil water content.
Almost all of the incidents of water course contamination in the Southwestern
Region of Ontario were related to land application of manure. Results from the
Ontario Farm Groundwater Quality Survey indicated that farmstead drinkingwater wells were more likely to be contaminated where manure was spread.264
returns from cattle,” Journal of Agricultural Science (Cambridge), 112, p. 205; S.C. Jarvis, J.H. Macduff,
J.R. Williams, and D.J. Hatch, 1989b, “Balances of forms of mineral N in grazed grassland soils:
Impact on N losses,” Proceedings of the XVI International Grassland Congress, Nice, p. 151.
260
S.P. Cuttle and D. Scholefield, 1995, “Management options to limit nitrate leaching from
grassland,” Journal of Contaminant Hydrology, 20, p. 299.
261
N.J. Hutchings and I.S. Kristensen, 1995, “Modelling mineral nitrogen accumulation in grazed
pasture: Will more nitrogen leach from fertilized grass than unfertilized grass/clover?” Grass and
Forage Science, 50, p. 300.
262
J.C. Ryden, P.R. Ball, and E.A. Garwood, 1984, “Nitrate leaching from grassland,” Nature
(London), 311, p. 50.
263
Baldwin, 1981.
264
Goss, Barry, and Rudolph, 1998a, D.L. Rudolph, D.A.J. Barry, and M.J. Goss, 1998b,
“Contamination in Ontario farmstead domestic wells and its association with agriculture: 2. Results
from multilevel monitoring well installations,” Journal of Contaminant Hydrology, 32, p. 295.
130
Walkerton Inquiry Commissioned Paper 6
Volatilization of ammonia represents the largest loss of N from manure.
Beauchamp et al. and Paul et al. found that the three most important variables
that influence NH3 volatilization appear to be temperature, soil pH, and soil
texture.265 Other gaseous losses primarily influence the amount of NO–3-N that
remains in the soil, available to plants or for leaching to groundwater. The gaseous
loss, together with the rate at which organic nitrogen is mineralized, result in
considerable uncertainty about the availability of manure-N once it is incorporated
in the soil. For example, Pratt et al. observed that a greater proportion of N could
not be accounted for at an application of 1750 kg/ha N than at 500 kg/ha N.266
Beauchamp found that only about three-quarters of the ammonium-N fraction
was as available as an equivalent mass of fertilizer-N.267
Transportation of manure to sites of application Liquid manure is transported via
pipelines, tanker-trailers, or custom truck-spreaders. Equipment manufacturers
have increased tanker size to meet market demands. The mass of tanker and
contents often exceeds the capacity of the tractor brakes to stop a fully loaded
unit, which could lead to a spill.
Semi-solid manure is not easily transported and can result in spillage in transit.
Solid manure is somewhat easier to transport. The cost of transportation is high
because of the large volume-to-weight ratio and the relatively small concentration
of nutrients. Poultry manure tends to be the exception, and poultry producers
have greater opportunities to have the manure taken by other farmers.
The cost of transportation has also resulted in manure being spread more regularly
on fields close to the barn or storage than on more distant fields. The nutrient
levels, particularly of nutrients such as phosphorus that are less mobile in the
soil, can become excessive if such practices have continued over many years.
Nutrient management strategies are designed to ensure that excess nutrients are
not applied to the land, thereby reducing the risk to water resources. However,
implementing such strategies also means that manure needs to be transported
265
E.G. Beauchamp, G.E. Kidd, and G. Thurtell, 1982, “Ammonia volatilization from liquid dairy
cattle manure in the field,” Canadian Journal of Soil Science, 62, p. 11; J.W. Paul, E.G. Beauchamp,
H.R. Whiteley, and J.K. Sakupwanya, 1990, Fate of Manure Nitrogen at the Arkell and Elora Research
Stations 1988–1990, Report on Special Research Contract No. SR8710-SW001, Ontario Ministry
of Agriculture and Food.
266
P.F. Pratt, A.E.M. Chirnside, and R.G. Scarborough, 1976, “A four-year field trial with animal
manures,” Hilgardia, 44, p. 99.
267
E.G. Beauchamp, 1986, “Availability of nitrogen from three manures to corn in the field,”
Canadian Journal of Soil Science, 66, p. 713.
The Management of Manure in Ontario with Respect to Water Quality
131
farther from the storage sites, which may mean increased transportation from
one farm to another.
Transportation of manure to the field has been a factor in some manure spills,
but it is the application, mainly of liquid manure, that is the most frequently
reported cause of manure entering surface water bodies.
Impacts of application techniques There are three main methods of application:
broadcasting (solid, semi-solid, and liquid manure), irrigation, and injection
(liquid manure). The mode of application has the greatest effect on the amount
of volatilization of ammonia. Importantly, the more nitrogen lost through this
route, the less that is potentially available to be lost to water resources, but the
impacts on the environment are more extensive and associated odour issues greater.
Liquid manure is applied to the soil surface of arable land either from a tanker
(broadcasting) or by using a sprayer linked to pipes that are connected to the
storage system (irrigation). Broadcasting has traditionally used a splash-plate
to distribute the manure, but low-level or low-pressure nozzles on booms are
increasingly used. These give a more even distribution or can be used to apply
the manure in bands between rows, thereby reducing odour release. Liquid
manure can also be directly injected below the soil surface (injection), using
hollow tines preceded by coulters to cut through crop residues. The injector
system can be mounted directly behind a tanker or set on a tool bar connected
to the three-point hitch of a tractor and linked to a stationary tanker via a
flexible hose.
Broadcast application of liquid manure from a tanker has resulted in fewer
than a third of the problems encountered when using spray irrigation, a practice
that is declining in popularity. Equipment failure has been the cause of 27% of
spills associated with the land application of manure.
The techniques for both irrigation and injection are well developed, and
manufacturers continue to improve the equipment for surface-spreading liquid
manure from tankers. They are improving the uniformity of application, which
also helps to reduce odour. Flow meters enable operators to apply liquid manure
more judiciously.
The availability of nutrients, particularly nitrogen, to a subsequent crop differs
between these two systems for manure application, mainly because of differences
132
Walkerton Inquiry Commissioned Paper 6
in the potential for gaseous losses (table 3-17).268 Ammonia loss during sprinkler
irrigation of pig manure ranged from 14–37% of total Kjeldahl nitrogen present
in the slurry.269 The pH of the slurry also increased, which would promote
greater volatilization once the manure reached the soil. Band-spreading reduces
NH3 volatilization compared with splash plates.
Up to 100% of the ammonia present in applied manures may be lost within a
few days to a few weeks if left on the soil surface.270 When liquid cattle manure
was injected as a side-dressing for corn, the N was 60% as available fertilizer-N.
When the manure was surface-applied as a side dressing, its N was only 33%
as available fertilizer-N. The reduced availability was attributed to ammonia
volatilization.271
The total nitrogen available to crops is generally greater after injection than after
surface spreading, with injection reducing ammonia volatilization by 85–95%
compared with surface spreading.272 Furthermore, the possibility of surface runoff
immediately after application is greater with surface spreading than injection.
Table 3-17 Comparison of Different Methods of Manure Application on
the Losses of Ammonia by Volatilization
Method of Application
Type of Waste
% Nitrogen lost
0–7 days
Broadcast
Solid
Liquid
15–30
10–27
Broadcast with immediate
cultivation
Solid
Liquid
1–5
1–8
Injection
Liquid
1–5
Sprinkler irrigation
Liquid
14–37
Sources: R.J. Fleming, 1988, An Expert System for the Selection/Design of Swine Manure Handling Methods,
M.Sc. Thesis, Univ. of Guelph; J.J. Meisinger and G.W. Randall, 1991, “Estimating nitrogen budgets for soil-crop
system,” Managing Nitrogen for Groundwater Quality and Farm Profitability, R.F. Follet, D.R. Keeney, and R.M.
Cruse (eds.) (Madison, WI: SSSA), p. 85; J. Van der Molen, H.E. Van Faasen, M.Y. Leclerc, R. Vriesma, and W.J.
Chardon, 1990a, “Ammonia volatilisation from arable land after application of cattle slurry: 1. Field estimates.”
Netherlands Journal of Agricultural Science, 38, p. 145.
268
Ibid.
L.M. Safley Jr., J.C. Baker, and P.W. Westerman, 1992, “Loss of nitrogen during sprinkler
irrigation of swine lagoon liquid,” Bioresource Technology, 40, p. 7.
270
Beauchamp, Kidd, and Thurtell, 1982; Paul et al., 1990.
271
Beauchamp, 1983.
272
Paul, 1991.
269
The Management of Manure in Ontario with Respect to Water Quality
133
Incorporating manure by tillage immediately after application dramatically
reduces runoff losses. In trials using simulated rainfall, King et al. found that
more NH4+ and phosphorus were lost in surface runoff immediately following
surface spreading than after incorporation or injection of manure.273 Generally,
runoff-N losses are small, 3 kg/ha N annually or less.274 However, a considerable
amount of runoff may occur in the presence of a shallow hardpan.275 Large
losses of N can occur by subsurface flow through tile drains.276 On arable land
in the Netherlands, losses of N through tile drains averaged as much as 22 kg
N/ha/y during a 10-year period.277
Although injection has been recommended to reduce the losses from
volatilization, gaseous loss associated with this technique mainly results from
denitrification rather than NH3 volatilization.278 The denitrification occurred
mainly in the region immediately around the slit. 279 Compared with
broadcasting, injection requires greater tractor power and less manure can be
applied per hour. Therefore, cost and the small window of time available to
most farmers in the spring often limit the potential use of injection.
273
D.J. King, G.C. Watson, G.J. Wall, and B.A. Grant, 1994, The Effects of Livestock Manure
Application and Management on Surface Water Quality, Summary Technical Report (London, ON:
GLWQP-AAFC Pest Management Research Centre, Agriculture and Agri-Food Canada).
274
D.J. Nichols, T.C. Daniel, and D.R. Edwards, 1994, “Nutrient runoff from pasture after
incorporation of poultry litter of inorganic fertilizer,” Soil Science Society of America Journal, 58,
p. 1224; Meisinger and Randall, 1991; D.W. Blevins, D.H. Wilkison, B.P. Kelly, and S.R. Silva,
1996, “Movement of nitrate fertilizer to glacial till and runoff from a claypan soil,” Journal of
Environmental Quality, 25, p. 584; G.J. Gascho, R.D. Wauchope, and J.G. Davis, 1998,
“Nitrate-nitrogen, soluble, and bioavailable phosphorus runoff from simulated rainfall after fertilizer
application,” Soil Science Society of America Journal, 62, p. 1711.
275
M.J. Goss, K.R. Howse, P.W. Lane, D.G. Christian, and G.L. Harris, 1993, “Losses of nitratenitrogen in water draining from under autumn crops established by direct drilling or mouldboard
ploughing,” Journal of Soil Science, 44, p. 35; R.K. Hubbard, R.A. Leonard, and A.W. Johnson,
1991, “Nitrate transport on a sandy coastal plain soil underlain by plinthite,” Transactions of the
American Society of Agricultural Engineers, 34, p. 802; R. Lowrance, 1992, “Nitrogen outputs from
a field-size agricultural watershed,” Journal of Environmental Quality, 21, p. 602.
276
A.J.A. Vinten, 1999, “Predicting nitrate leaching from drained arable soils derived from glacial
till,” Journal of Environmental Quality, 28, p. 988.
277
G.J. Kolenbrander, 1969, “Nitrate content and nitrogen loss in drainwater,” Netherlands Journal
of Agricultural Science, 17, p. 246.
278
R.B. Thompson, J.C. Ryden, and D.R. Lockyer, 1987, “Fate of nitrogen in cattle slurry following
surface application or injection to grassland,” Journal of Soil Science, 38, p. 689; S.D. Comfort,
K.A. Kelling, D.R. Keeney, and J.C. Converse, 1990, “Nitrous oxide production from injected
liquid dairy manure.,” Soil Science Society of America Journal, 54, p. 421.
279
S.O. Petersen, 1992, “Nitrification and denitrification after direct injection of liquid cattle
manure,” Acta Agriculturae Scandinavica. Section B, Soil and Plant Science, 42, p. 94.
134
Walkerton Inquiry Commissioned Paper 6
Poor distribution patterns result from all types of manure spreaders due largely
to the nature of the material. Using injection on rolling topography has also
resulted in problems.
The most frequently reported route by which liquid manure can contaminate
surface water courses is in outflow from tile-drain systems. Fleming and
Bradshaw identified macropore flow of manure liquids into subsurface drains
after spreading.280 Pre-tillage tines have been incorporated into injection
machinery to limit macropore flow (J. Houle & Fils Inc., Drummondville,
Quebec; Husky Farm Equipment Ltd., Alma, Ontario).
Large tankers can cause problems with soil compaction in the field. Compaction
is a significant concern because it can increase surface runoff as well as decrease
crop yield. This problem is also being reduced by new machine design (e.g.,
tankers with tracks now made by Husky Mfg.).
Solid manure is applied by spreader machines that propel the manure to the
rear or to the side. Although new machines operate effectively, the spread tends
to become less uniform with use. The more variable nature of solid manure
also tends to reduce the uniformity of nutrient application.
Bacteria Evidence from the Ausable-Bayfield Conservation Authority indicates
that bacteriological contamination from tile drains can be greater after injection
than after surface spreading.281 Transport of bacteria in surface runoff was similar
for surface spreading, incorporation, or injection of manure.282 When the system
was modified by placing a cultivating tine ahead of the injector tine, there was
a significant reduction in bacterial transport through runoff. Pre-tillage of soil
before spreading liquid manure minimized the direct impact of manure on the
quality of tile-drain effluent.283
280
R.J. Fleming and S.H. Bradshaw, 1991, Macropore Flow of Liquid Manure (Saskatoon, SK:
Canadian Society Agric. Eng.), Paper No. 91-241; R.J. Fleming and S.H. Bradshaw, 1992a, Detection
of Soil Macropores Using Smoke (Saskatoon, SK: Can. Soc. Agric. Eng.), Paper No. 92-103; R.J.
Fleming and S.H. Bradshaw, 1992b, Contamination of Subsurface Drainage Systems during Manure
Spreading (St. Joseph, MI: Am. Soc. Agric. Eng.), Paper No. 92-2618.
281
M.E. Foran, D.M. Dean, and H.E. Taylor, 1993, “The land application of liquid manure and
its effect on tile drain water and groundwater quality,” Agricultural Research to Protect Water Quality:
Proceedings of the Conference. February 21–24, Minneapolis, MN (Ankeny, IA: Soil and Water
Conservation Society), p. 279.
282
King et al., 1994.
283
Fleming and Bradshaw, 1992b.
The Management of Manure in Ontario with Respect to Water Quality
135
Bacteria from poultry manure were not detected in runoff when the manure was
applied to bare soil, but was present when the manure was applied to grassland.284
In the first day after applying liquid manure, more bacteria may be lost in overland
flow from no-till land than from ploughed land, but the rate of decline in the
concentration of bacteria in the runoff water can also be greater.285
Timing of manure applications When determining when to apply manure,
producers have to consider several factors including the risk of soil compaction,
likelihood of runoff, and nutrient loss through NH3 volatilization. The timing
of manure applications is critical both for the availability of nitrogen to crops
and for potential impacts on the environment. As manure storage on many
farms is limited, the common periods for application are the fall, winter, and
spring. In spring, applications may be as a pre-plant fertilization or as a side- or
top-dressing. The experimental evidence shows that compared with spring
applications, manuring land in fall or winter results in lower recovery of applied
nitrogen by the crops and greater risk of leaching or surface runoff and
denitrification (table 3-18).286
Current guidelines in Ontario state that manure should “not be spread on
frozen or ice-covered soil.” If the soil is unfrozen, then winter spreading should
not occur on land with more than a slope of 3%. In an emergency, winter
spreading is permitted, but only on land with residues or vegetation and only
where there is no danger of runoff or flooding.
Fleming and Fraser have reviewed the literature on winter spreading of manure
in Ontario.287 In general, winter spreading of manure results in greater nutrient
losses than at other times. As many soils are impervious when frozen, manure
spread on the surface is likely to be carried off in runoff from snow-melt or
rain. The likelihood of surface runoff does not appear to differ whether the
manure is spread on frozen soil or snow or onto a cover crop.
284
J. Giddens and A.P. Barnett, 1980, “Soil loss and microbiological quality of runoff from land
treated with poultry litter,” Journal of Environmental Quality, 9, p. 518.
285
King et al., 1994
286
Thompson, Ryden, and Lockyer, 1987; M.J. Goss, W.E. Curnoe, E.G. Beauchamp, P.S. Smith,
B.D.C. Nunn, and D.A.J. Barry, 1995a, An Investigation into the Management of Manure Nitrogen
to Safeguard the Quality of Groundwater, COESA Report No. LMAP- 013/95 prepared for Research
Branch. Agriculture and Agri-Food Canada.
287
R. Fleming and H. Fraser, 2000, Impacts of Winter Spreading of Manure on Water Quality: Literature
Review (Ridgetown, ON: Ridgetown College, University of Guelph).
136
Walkerton Inquiry Commissioned Paper 6
The effect of slope has received little critical attention. Losses to the environment
depend on whether the first snow-melt or rainfall event results in runoff or
infiltration, which is greatly influenced by weather factors. However, solid
manure may reduce the amount of runoff. Loss of NH3 by volatilization may
be reduced if the manure is covered by snow after application. Clearly, as current
weather patterns are critical, it is difficult to predict whether there will be
significant environmental contamination in any one winter. Local weather
records might be used to identify locations where the risks are greatest, but
Fleming and Fraser concluded that the evidence supports the adherence to the
current guidelines for spreading.288
Table 3-18 Sinks for N Following Application of Slurry
Nitrogen Sinks†
Application
Apparent Recovery NH3 Volatilization
Loss
in Herbage
Denitrification
Loss
Total
Sinks
kg N/ha (%)
Winter E xperiment
Surface spread slurry
49.0 (19.8)
77.1 (30.8)
29.9 (12.1)
156.1 (62.9)
Injected slurry
82.7 (33.4)
2.1 (0.9)
52.7 (21.3)
137.5 (55.4)
Injected slurry † plus
nitrapyrin
(nitrification
inhibitor)
90.1 (36.3)
2.1 (0.9)
22.7 (9.2)
114.9 (46.3)
17.0%
25.3%
98.2% (42.6%)
–
Surface spread slurry
66.9 (25.5)
53.0 (20.2)
4.5 (1.7)
124.4 (47.5)
Injected slurry
93.9 (35.5)
2.4 (0.9)
17.7 (6.8)
114.0 (43.5)
Injected slurry † with
nitrapyrin
109.9 (42.0)
2.4 (0.9)
14.0 (5.3)
126.3 (48.2)
13.8%
21.1%
182% (74.8%)
–
CV‡
Spring E xperiment
CV‡
† In both experiments leaching losses from all treatments were negligible
‡ Coefficients of variation determined as follows:
Apparent recovery: from the total apparent recoveries for each of the four plots for the three treatments in
each experiment.
NH3 volatilization: from the total NH3 loss determined for each of the three tunnels used for the surface
application treatment.
Denitrification: the average coefficient of variation for all denitrification measurements in each experiment. In
parentheses, the average for values greater than 0.10 kg N/ha/d.
Source: Thompson et al., 1987.
288
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
137
Effect of manure treatment and soil conditions on NH3 volatilization As indicated
above, much research has been devoted to examining the loss of ammonia to
the atmosphere due to volatilization after surface applications of manure. Loss
from bare soil is less than losses from grassland,289 arable land with surface
residues, or growing crops.290
Key factors that influence the volatilization from surface-applied slurries are
wind speed, temperature, the pH at the surface of the slurry, and its dry matter
content.291 After adjusting for pH and temperature, Sommer and Olesen found
a sigmoid relationship between the cumulative loss of ammonia and the dry
matter content, such that the loss was greatest for a dry matter content between
4% and 12%.292
A transfer model related the rate of ammonia volatilization to the concentration
of the gas at the surface of a layer of slurry and the background concentration
in the atmosphere.293 The model takes into account the depth of soil in which
the slurry is distributed, evaporation of soil water, and infiltration of rain.
Before it can be used by farmers, the model needs to be extended to predict pH
at the volatilizing surface since this also affects the rate of loss.
The effect of mechanically removing particulate organic matter from slurry
applied to grassland has been examined. Thompson et al. found that in the
initial 5 h, the rate of NH3 volatilization was slower from cattle slurry that had
passed through a 3 mm mesh than from unseparated slurry.294 Later the relative
rates were reversed, so that the losses from the two treatments over 6 days were
289
R.B. Thompson, J.C. Ryden, and D.R. Lockyer, 1990, “Ammonia volatilization from cattle
slurry following surface application to grassland,” Plant and Soil, 125, p. 109.
290
H.-G. Bless, R. Beinhauer, and B. Sattelmacher, 1991, “Ammonia emissions from slurry applied
to wheat stubble and rape in North Germany,” Journal of Agricultural Science, 117, p. 225.
291
R. Van den Abbeel, D. Paulus, C. De Ruysscher, and K. Vlassak, 1990, “Gaseous N losses after
the application of slurry: Important or not?” Fertilization and the Environment, R. Merckx, H.
Vereecken, and K. Vlassak (eds.), (Leuven, Belgium: Leuven University Press), p. 241; S.G. Sommer,
J.E. Olesen, and B.T. Christensen, 1991, “Effects of temperature, wind speed and air humidity on
ammonia volatilization from surface-applied cattle slurry,” Journal of Agricultural Science
(Cambridge), 117, p. 91.
292
S.G. Sommer and J.E. Olesen, 1991, “Effects of dry matter content and temperature on ammonia
loss from surface-applied cattle slurry,” Journal of Environmental Quality, 20, p. 679.
293
J. Van der Molen, A.C.M. Beljaars, W.J. Chardon, W.A. Jury, and H.G. Van Faasen, 1990b,
“Ammonia volatilisation from arable land after application of cattle slurry: 2. Derivation of a
transfer model,” Netherlands Journal of Agricultural Science, 38, p. 239.
294
Thompson, Ryden, and Lockyer, 1990.
138
Walkerton Inquiry Commissioned Paper 6
35% and 38% respectively. Stevens et al. investigated particle separation,
dilution, and a washing treatment for cattle slurry applied to grassland.295 A
50% reduction in NH3 volatilization, compared with untreated slurry, could
be obtained by removing solids using a 0.4 mm mesh, or using a 10 mm mesh
and diluting the strained material with 86% by volume of water, or by using a
2 mm mesh and washing with a 53% volume of water after manure application.
Acidification of manure is potentially one way of reducing volatilization of
ammonia and hence nitrogen loss. Stevens et al. observed a 90% decrease in
volatilization by acidifying cattle slurry to pH 6.296 Acidifying cattle slurry to
pH 5.5 reduced volatilization by 14 to 57%.297 Acidifying pig slurry and adding
sphagnum peat moss also decreased ammonia volatilization by at least 74.6%.298
Elemental sulphur and calcium carbonate increased the volatilization. While
acidification alone did not reduce the effectiveness of the slurry nitrogen for
wheat growth, the combination of 1% sphagnum moss and calcium carbonate
impaired plant growth. Adding 1.4% by volume of 10 molar nitric acid to
slurry reduced volatilization by 75% compared with unamended slurry, and
increased the nitrogen content of the slurry by 2 g N/L. The acidified slurry
had a superior balance of mineral N, P, and K for fertilizing grass. However, in
practice, acidification of manure has not been found to be cost-effective.299
A combination of acidification and solids separation can produce benefits. Stevens
et al. obtained the same 90% decrease in volatilization by acidification to pH 6.5
together with dilution with a 50% volume of water, and by acidification to 6.5
following removal of solids using a 0.4 mm mesh.300 For acidified whole slurry, the
efficiency of nitrogen use was only 54% of that for mineral fertilizer.301 However,
after removal of solids using a 1.1 mm mesh and acidification, the efficiency of
295
R.J. Stevens, R.J. Laughlin, and J.P. Frost, 1992a, “Effects of separation, dilution, washing and
acidification on ammonium volatilization from surface applied cattle slurry,” Journal of Agricultural
Science (Cambridge), 119, p. 383.
296
Ibid.
297
B.F. Pain, R.B. Thompson, Y.J. Rees, and J.H. Skinner, 1990, “Reducing gaseous losses of
nitrogen from cattle slurry applied to grassland by the use of additives,” Journal of the Science of
Food and Agriculture, 50, p. 141.
298
T. Al-Kanani, E. Akochi, A.F. Mackenzie, I.A. Ali, and S.F. Barrington, 1992b, “Organic and
inorganic amendments to reduce ammonia losses from liquid hog manure,” Journal of Environmental
Quality, 21, p. 709.
299
R.J. Stevens, 1997, [personal communication].
300
Stevens, Laughlin, and Frost, 1992a.
301
R.J. Stevens, R.J. Laughlin, J.P. Frost, and R. Anderson, 1992b, “Evaluation of separation plus
acidification with nitric acid and separation plus dilution to make cattle slurry a balanced, efficient
fertilizer for grass and silage,” Journal of Agricultural Science (Cambridge), 119, p. 391.
The Management of Manure in Ontario with Respect to Water Quality
139
nitrogen use from the slurry was 88%. The lower efficiency of the whole slurry was
attributed to enhanced denitrification and contamination of plant leaves.
Some other manure treatments appear to have little effect on the conservation of
ammonia after land application. Volatilization of ammonia from grassland was
the same for unamended pig slurry and pig slurry treated by anaerobic digestion.302
3.2.6.3 Summary
There has been no systematic investigation of the runoff or leaching of
contaminants from grazed fields in Ontario. It is considered that surface runoff
is not an important pathway for water or pathogens from pastures to enter streams.
Most runoff originates close to the stream bank rather than from the main area
of the field. Cattle accessing watercourses also contribute to soil, nutrients, and
pathogens entering the water. Because grazing animals excrete urine and feces in
patches, nitrate leaching from grazed pastures is greater than from cut forage.
Groundwater loading of N by leaching from grazed land can compare with or
even exceed that from arable land, but current stocking rates in Ontario make
this loading unlikely to be a significant source of groundwater contamination.
Most manure is applied to cropped land. Solid manure is surface spread.
Transporting manure to the field has been a factor in some manure spills, but
the application of (mainly liquid) manure has been the most frequently reported
cause of manure entering surface water bodies. Liquid manure may be surface
spread from a tanker, applied by irrigation, or injected using hollow tines. The
mode of application greatly affects the volatilization of ammonia. Sprinkler
irrigation tends to result in the greatest gaseous loss on application, but failure
to incorporate liquid manure after application can also result in large losses.
The type of application can influence the loss of potential contaminants to
surface and groundwater. Potential for NO–3 leaching after application can be
influenced by the volatilization of NH3 at application. Incorporating the manure
after application helps conserve nitrogen, but manure treatment has little effect
on gaseous loss. Application to no-till land provides greater opportunity for
gaseous loss, but leaving manure on the surface of bare soil can also encourage
runoff. Bacterial movement into tile lines can be greater after injection than
after surface application.
302
Pain et al., 1990.
140
Walkerton Inquiry Commissioned Paper 6
The timing of application also affects the risk of water contamination, with
fall, winter, and early spring applications likely to have the most negative
impacts.
3.2.7 Fate of manure components applied to the soil
The producer applies manure to meet the nutrient demands of the crop.
However, because the ratio of N, P, and K in manure is not identical to crop
requirements, additional mineral fertilizer may be required if excess application
of P or K is to be avoided. After field application, manure forms a diffuse
source. The nutrients in the manure may be taken up by the crops or become
available for transport. Nitrogen can be lost in gaseous form as ammonia or
nitrified to nitrate which is then subject to leaching or denitrification.
3.2.7.1 Nitrogen
The proportion of the total-N present in the ammoniacal (NH3 and NH4+)
form is a key manure characteristic for two reasons: it can be lost as gaseous
ammonia and it is generally thought of as being as available as the N in granular
fertilizer.303 However, when mixed in soil, ammoniacal-N is not quite as available
as fertilizer-N. It may be immobilized by being taken up by soil microbes or
adsorbed onto clays.304 To preserve nutrients following surface spreading, the
material needs to be tilled into the soil as soon as possible after application,
particularly to minimize the loss of ammonia by volatilization. Incorporating
manure reduced the ammonia volatilization from 32% of total ammoniacal
nitrogen to about 16%.305 Nevertheless, incorporation is not always possible.
Overall, our ability to predict losses following application is far from complete.
303
E.G. Beauchamp and J.W. Paul, 1989, “A simple model to predict manure nitrogen availability
to crops,” Nitrogen in Organic Wastes Applied to Soils, J.A. Hansen and and K. Henrikson (eds.),
(London: Academic Press), p. 140; Beauchamp, 1983.
304
T.H. Flowers and P.W. Arnold, 1983, “Immobilization and mineralization of nitrogen in soils
incubated with pig slurry or ammonium sulphate,” Soil Biology & Biochemistry, 15, p. 329;
T.Z. Castellanos and P.F. Pratt, 1981, “Mineralization of manure nitrogen: Correlation with
laboratory indexes,” Soil Science Society of America Journal, 45, p. 354; Beauchamp, 1986; J.W. Paul
and E.G. Beauchamp, 1994, “Short-term nitrogen dynamics in soil amended with fresh and
composted cattle manures,” Canadian Journal of Soil Science, 74, p. 147.
305
Van der Molen et al., 1990a.
The Management of Manure in Ontario with Respect to Water Quality
141
Within the soil, the ammonium ions in the manure are added to those resulting
from mineralization of organic nitrogen in soil organic matter and from organic
forms in the manure.
The NH4+ ions undergo oxidative reactions first to form nitrite (NO–2) and
then nitrate (NO–3), but some convert into dissolved ammonia and are subject
to volatilization.306 Very little NO–2 is present in most soils in Ontario because
it is rapidly converted to NO3–. Both NO–3 and NH4+ can be taken up by plants,
but are also subject to further transformations. NO–3 can be converted to gaseous
nitrous oxide and nitrogen gas under anaerobic conditions. This denitrification
process occurs more readily with organic nitrogen sources such as livestock
manure. The amount of subsurface denitrification is a function of manure
type, soil type, time of application, and depth to groundwater.307 In contrast,
the remaining organic-N fraction of manure may be only marginally available
in the year of application.308 The degradability of the organic fraction of manure
is not well understood in terms of the N-release dynamics in the field.
Few researchers have reported losses of nitrous oxide from cropped land fertilized
with manure, but losses under corn were comparable with losses from grassland
given much greater nitrogen applications.309
The organic matter in cattle manure provides additional carbon substrate for
denitrifying bacteria in the soil. This can stimulate denitrification for long
periods after slurry applications. The emission of gases such as N2O, NO, and
NO2 due to denitrification from manured soils is likely to be greater than that
from soils receiving mineral nitrogen fertilizers.310 Effect of the application of
306
Beauchamp, 1983; Thompson, Ryden, and Lockyer, 1987.
Just as ammonia volatilization can reduce the amount of N available for leaching, denitrification
below the root zone, or in riparian zones and wetlands, can reduce the amount of NO3– available to
move to a water resource. However, the proportion of NO3– that is reduced to nitrogen gas (N2)
(rather than to N2O, a greenhouse gas) is uncertain and not easily controlled. Consequently, it is
still better to minimize leaching of NO3– rather than encouraging denitrification to protect water
resources; D.L. Burton, E.G. Beauchamp, R.G. Kachanoski, and R.W. Gillham, 1991, “Impact of
livestock manure and fertilizer application on nitrate contamination of groundwater,” Proceedings
– Environmental Research: 1991 Technology Transfer Conference, Volume I. Toronto, ON, November
1991, Research and Technology Branch, Environment ON, p. 180.
308
Beauchamp, 1986; Paul, 1991.
309
M.J. Eichner, 1990, “Nitrous oxide emissions from fertilized soils: Summary of available data,”
Journal of Environmental Quality, 19, p. 272.
310
R.B. Thompson and B.F. Pain, 1990, “The significance of gaseous losses of nitrogen from livestock
slurries applied to agricultural land,” Fertilization and the Environment, R. Merckx, H. Vereecken,
and K. Vlassak (eds.), (Leuven, Belgium: Leuven University Press), p. 290.
307
142
Walkerton Inquiry Commissioned Paper 6
unamended cattle slurry to grassland was tested by Burford et al.311 The air in
the soil under a layer containing slurry was found to contain up to 680 ppm of
N2O. The actual gaseous loss of nitrogen was not determined, but was deemed
significant. It was suggested that further work be carried out investigating
gaseous transfer. Paul et al. showed that manured soil produced N2O and NO
due to nitrification and denitrification processes.312 Production of the gases
was greater when the manure was applied as slurry than as compost. As a
minimum water content of the soil was important for denitrification losses
from manure,313 the additional water applied could have been an important
factor in generating losses from the slurry.
Pain et al. observed a rate of 0.91 kg N/ha/day for denitrification a few weeks
after slurry application to a freely drained loam soil in the fall.314 The total
losses were about 29% of the ammoniacal-N applied. Acidification of the
manure increased the loss to 41% of the applied ammonium-N. The nitrification
inhibitor, dicyandiamide, reduced denitrification to an extent depending on
the concentration applied in the slurry. Another nitrification inhibitor,
nitrapyrin, had little effect on the rate of denitrification (table 3-18).
Denitrification after a spring application was much less than that after a fall
application on this soil, and little took place from a poorly drained loam after
applying manure at either time. Surface application of manure in summer was
associated with smaller losses of nitrogen by denitrification.315
Clearly, the information already presented establishes that volatilization of NH3
is a major route for N-loss during and immediately after manure application.
The magnitude of all the gaseous losses of N is difficult to estimate. Consequently,
reports suggest (see section 3.2.8) that ground-water contamination with NO–3 is
311
J.R. Burford, D.J. Greenland, and B.F. Pain, 1976, “Effects of heavy dressings of slurry and
inorganic fertilizers applied to grassland on the composition of drainage waters and the soil
atmosphere,” Agriculture and Water Quality. Technical Bulletin. No. 32 (London: Ministry of
Agriculture, Fisheries and Food), p. 432.
312
J.W. Paul, E.G. Beauchamp, and X. Zhang, 1993, “Nitrous and nitric oxide emissions during
nitrification and denitrification from manure-amended soil in the laboratory,” Canadian Journal
of Soil Science, 73, p. 539.
313
S.G. Nugroho and S. Kuwatsuka, 1990, “Concurrent observation of several processes of nitrogen
metabolism in soil amended with organic materials. I. Effect of different organic materials on
ammonification, nitrification, denitrification, and N2 fixation under aerobic and anaerobic
conditions,” Soil Science and Plant Nutrition, 36, p. 215.
314
Pain et al., 1990.
315
Van den Abbeel et al., 1990.
The Management of Manure in Ontario with Respect to Water Quality
143
greater in areas where animal manure is applied regularly compared with areas
receiving predominantly mineral-N fertilizer.316
3.2.7.2 Phosphorus and other nutrients
Many fields in Ontario that have received regular applications of manure contain
large amounts of phosphorus. Applying increasing amounts of cattle manure
to soils in Alberta over 11 years enhanced the total phosphorus content of the
soil and the available phosphorus.317 From agronomic considerations, one would
want to apply only as much phosphorus, either as manure or fertilizer, as is
required for most economic crop production. Current recommendations assume
that 40% of the phosphorus in manure is as available in the year of application
as from commercial fertilizer.318 However, this assumption has not been tested
thoroughly and probably underestimates the actual value. A 50–60% availability
of manure-P is usually assumed in the UK.319 While 29–39% of P in liquid
manure from cattle, poultry, and swine was apparently recovered in plants
under greenhouse conditions, 42% of fertilizer-P was recovered.320 This means
that manure-P would be up to 93% as available as from commercial fertilizer.
The phosphorus applied may be combined in inorganic or organic molecules.
The organic-P in cattle, swine, and poultry slurries was 1–15% of the total-P,
with the rest being inorganic (as orthophosphate).321 The proportion of organicP was 5–15% of the total-P after various manures were stored for two months;
316
W.F. Ritter and A.E.M. Chirnside, 1987, “Influence of agricultural practices on nitrates in the
water table aquifer,” Biological Wastes, 19, p. 165; R. Fleming, M. MacAlpine, and C. Tiffin, 1998,
Nitrate Levels in Soil, Tile Drainage Water and Shallow Groundwater under a Variety of Farm
Management Systems (Vancouver, B.C.: CSAE), Paper 98-101.
317
C. Chang, T.G. Sommerfeldt, and T. Entz, 1991, “Soil chemistry after eleven annual applications
of cattle feedlot manure,” Journal of Environmental Quality, 20, p. 475.
318
Ontario, Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 1999a, Field Crop
Recommendations 1999–2000, Publication 296 (Toronto, ON: Queen’s Printer), p. 154.
319
K.A. Smith, R.J. Unwin, and J.H. Williams, 1985, “Experiments on the fertilizer value of animal
waste slurries,” Long Term Effects of Sewage Sludge and Farm Slurries Applications, J.H. Williams et
al. (eds.), (New York: Elsevier Science); R.J. Unwin, 1987, “The accumulation of manure-applied
phosphorus and potassium in soils,” Journal of the Science of Food and Agriculture, 40, p. 315.
320
K.A. Smith and T.A. Van Dijk, 1987, “Utilization of phosphorus and potassium from animal
manures on grassland and forage crops,” Animal Manure on Grassland and Fodder Crops: Fertilizer
or Waste?, H.G. Van Der Meer et al. (eds.), (Boston: Martinus Nijhoff ).
321
R.G. Gerritse and R. Vriesema, 1984, “Phosphate distribution in animal waste slurries,” Journal
of Agricultural Science, 102, p. 159.
144
Walkerton Inquiry Commissioned Paper 6
this was considered to be an end-result equilibrium following microbial
transformations.322 The inorganic-P was present as crystals or precipitates of
calcium phosphates. Barnett indicated that the proportions of organic-P and
inorganic-P in manure affected the fertilizing value, noting that crop response
is directly related to the inorganic-P content.323 On the other hand, the organicP fraction (inositols, phospholipids, and nucleic acids) is marginally available
but to varying extents.
Barnett also noted that the manures from monogastric animals (swine, poultry)
usually contained much more P (22–23 g/kg P dry matter) than those from
ruminant animals (cattle, sheep) (4–6 g/kg P dry matter) although there may
be large variations in concentration. Only a small part of the organic-P appears
to move readily through the soil and is probably of microbial origin, of high
molecular weight, and only slightly adsorbed by soils.
Most of the P occurs in feces. Organic-P in the nucleic acid and phytate (inositol)
forms can be persistent since mineralization of these forms is a slow process.324
Van Faassen and Van Dijk argued that the differences in the fertilizing value of
manure-P and fertilizer-P cannot be due to the presence of organic-P because
it constitutes only 10–20% of the total-P in manure.325
The concentration of P in the soil solution is a dynamic function of physical
and chemical processes that control the solubility of mineral P, the release of P
from organic forms, and the amounts removed by plants and microorganisms.326
The organic forms of P can be sub-divided into labile and resistant fractions,
with the labile fraction tending to remain constant unless severely depleted by
mineralization.327 The maximum amount of P that is present in solution in
322
H.G. Van Faassen and H. Van Dijk, 1987, “Manure as a source of nitrogen and phosphorus in
soils,” Animal Manure on Grassland and Fodder Crops: Fertilizer or Waste? H.G. Van der Meer et al.
(eds.), (Boston: Martinus Nijhoff ).
323
G.M. Barnett, 1994a, “Phosphorus forms in animal manure,” Bioresource Technology, 49, p. 139;
G.M. Barnett, 1994b, “Manure P fractionation,” Bioresource Technology, 49, p. 149.
324
Van Faassen and Van Dijk, 1987.
325
Ibid.
326
A.N. Sharpley, S.J. Smith, O.R. Jones, W.A. Berg, and G.A. Coleman, 1992, “The transport of
bioavailable phosphorus in agricultural runoff,” Journal of Environmental Quality, 21, p. 30.
327
A.N. Sharpley and S.J. Smith, 1985, “Fraction of inorganic and organic phosphorus in virgin
and cultivated soils,” Soil Science Society of America Journal, 49, p. 127.
The Management of Manure in Ontario with Respect to Water Quality
145
soil water is related to the natural level of labile-P and how much additional P
has been applied as fertilizer in organic and inorganic form.328
3.2.7.3 Metals
Because copper and zinc are included in feed, considerable amounts can be
applied to soil in manure.329 The Zn content of soil increased in proportion
to the amount of manure applied, but the Cu content did not show a
significant change.330 Soil became more acid with the application of cattle
manure331 and pig slurry.332 Long-term application of pig slurry to grassland
was investigated to establish how metals such as copper and zinc from feed
additives might affect the soil metal content.333 Total nickel and the lead
content were not increased by slurry application. However, the copper and
zinc content of the soil was increased and the availability of the metal to the
herbage was enhanced. The application of 200 m3/ha/y of pig slurry acidified
the soil, tending to reduce the soil microbial biomass, but the increase in
copper could also have affected the microbial population. The effect of cattle
manure was much smaller. Verloo and Willaert concluded that the actual
impact of slurry on heavy metal accumulation in soils and in the crops growing
on them depended on acidity.334 Continued application at high rates may
328
K.P. Raven and L.R. Hossner, 1993, “Phosphorus desorbtion quantity-intensity relationships in
soil,” Soil Science Society of America Journal, 57, p. 1501; A.N. Sharpley and S.J. Smith, 1989,
“Mineralization and leaching of phosphorus from soil incubated with surface-applied and
incorporated crop residue,” Journal of Environmental Quality, 18, p. 101.
329
A.L. Sutton, D.W. Nelson, V.B. Mayrose, and D.T. Kelly, 1983, “Effect of copper levels in
swine manure on corn and soil,” Journal of Environmental Quality, 12, p. 198.
330
Chang, Sommerfeldt, and Entz, 1991.
331
Ibid.
332
M.P. Bernal, A. Roig, A. Lax, and A.F. Navarro, 1992, “Effects of the application of pig slurry
on some physico-chemical and physical properties of calcareous soils,” Bioresource Technology, 42,
p. 233.
333
P. Christie, 1990 “Accumulation of potentially toxic metals in grassland from long-term slurry
application,” Fertilization and the Environment, R. Merckx, H. Vereecken, and K. Vlassak (eds.),
(Leuven, Belgium: Leuven University Press), p. 124.
334
M. Verloo and G. Willaert, 1990, “Direct and indirect effects of fertilization practices on heavy
metals in plants and soils,” Fertilization and the Environment, R. Merckx, H. Vereecken, and K.
Vlassak (eds.), (Leuven, Belgium: Leuven University Press), p. 79.
146
Walkerton Inquiry Commissioned Paper 6
result in toxic levels of copper in the long term,335 but this is not likely to
occur on neutral to alkaline soils.336
Organic matter amendments are thought likely to lead to increases in the
water-soluble forms of Zn rather than of Cu, due to the direct effects of the
organic matter and dissolved carbon and to indirect effects on other soil
properties (e.g., pH and redox status).337 The application of manure resulted
in a decrease in soil pH which, even two months later, was an important factor
in the dissolution of weakly bound metals.338 Thus, even if the water-solubleCu content of fresh liquid swine manure is relatively small,339 application of
manure to soil may mobilize some of the Cu and Zn already present from
previous applications.340 The fate of metals in manured soils is related to the
fate of organic matter, with little difference due to the type of manure.341
3.2.7.4 Bacteria
The potential for movement to, and eventual contamination of, water resources
by microorganisms depends on their concentration in manure at the time of
application and their survival. Manure may affect survival of bacteria: Östling
and Lindgren found that 20–40 times more indigenous Bacillus spores were
present on manured crops than on un-manured crops, and these numbers
335
K. Meeus-Verdinne, G. Neirinckx, X. Monseur, and R. de Borger, 1980, “Real or potential risk
of pollution of soil, crops, surface and groundwater due to land spreading of liquid manure,”
Effluent from Livestock, J.K.R. Gasser (ed.), (London: Applied Science), p. 399.
336
M.A. Anderson, J.R. McKenna, D.C. Martens, S.J. Donohue, S.T. Kornegay, and H.D.
Lindemann, 1991, “Long-term effects of copper rich swine manure application on continuous
corn production,” Communications in Soil Science and Plant Analysis, 22, p. 993.
337
L.M. Shuman, 1991, “Chemical forms of micronutrients in soil,” Micronutrients in Agriculture,
2nd ed., J.J. Mortvedt, F.R. Cox, L.M. Shuman, and R.M. Welch (eds.), (Madison, WI: Soil
Science Society of America). p. 113; P. Del Castilho, W.J. Chardon, and W. Salomons, 1993a,
“Influence of cattle-manure slurry application on the solubility of cadmium, copper and zinc in a
manured acidic, loamy-sand soil,” Journal of Environmental Quality, 22, p. 686.
338
W. Salomons and U. Förstner, 1984, Metals in the Hydrocycle (Berlin, New York: SpringerVerlag).
339
W.P. Miller, D.C. Martens, L.W. Zelazny, and E.T. Kornegay, 1986, “Forms of solid phase
copper in copper-enriched swine manure,” Journal of Environmental Quality, 15, p. 69.
340
P. Del Castilho, J.W. Dalenberg, K. Brunt, and A.P. Bruins, 1993b, “Dissolved organic matter,
cadmium, copper and zinc in pig slurry- and soil solution-size exclusion chromatography fractions,”
International Journal of Environmental Analytical Chemistry, 50, p. 91.
341
J. Japenga, J.W. Dalenberg, D. Wiersma, S.D. Scheltens, D. Hesterberg, and W. Salomons,
1992, “Effect of liquid animal manure application on the solubilization of heavy metals from soil,”
International Journal of Environmental Analytical Chemistry, 46, p. 25.
The Management of Manure in Ontario with Respect to Water Quality
147
remained constant with time to harvest.342 However, this was not the case for
bacteria originating in the manure itself, such as Clostridium, some coliforms,
and E. coli, all of which declined with time after manure application. The
survival of any non-indigenous bacteria depends on several factors including
soil pH, soil water content, organic matter content, soil texture, temperature,
availability of nutrients, adsorption properties of the soil (MacLean found that
soils containing clays with a large surface area can adsorb bacteria),343 and
biological interactions in the soil.344
Soil fauna can also be highly competitive. Pathogenic bacteria associated with
manure may not accumulate in soils containing earthworms. After 48 h, a
population of Salmonella introduced to soil containing earthworms was reduced
by a factor of four compared with Salmonella in a worm-free soil. Earthworms
also caused a small reduction in the population of the normal bacteria. Freeliving protozoa, nematodes, and the soil bacterium Bdellovibrio are also predators
of bacteria in the soil.345 Presence of these organisms may reduce or limit bacterial
numbers. Nonetheless, introduced bacteria may still be able to survive for an
extended period after manure application. On average, 10% of fecal coliforms
and fecal streptococci were still present in the soil 11 and 14 days respectively
after application of pig manure.346
The survival in soil of E. coli, including E. coli O157:H7, has received particular
attention. In cold soils (<5°C) the bacteria can survive for up to 100 days.
Survival periods are shorter in coarse-textured soils than in finer-textured soils
(figure 3-4). Campylobacter species appear to have somewhat shorter survival
times. C. jejuni survived in soil for at least ten days but this number could
double when the ambient temperature decreased to 6°C.347
342
C.E. Östling and S.E. Lindgren, 1991, “Bacteria in manure and on manured and NPK fertilized
silage crops,” Journal of the Science of Food and Agriculture, 55, p. 579.
343
A.J. MacLean, 1983, “Pathogens of animals in manure: Environmental impact and public health,”
Farm Animal Manures in the Canadian Environment (Ottawa: National Research Council of Canada
Associate Committee on Scientific Criteria for Environmental Quality), p. 103.
344
J. Abu-Ashour, D.M. Joy, H. Lee, H.R. Whiteley, and S. Zelin, 1994b, “Transport of
microorganisms through soil,” Water, Air, & Soil Pollution, 75, p. 141.
345
T.C. Peterson and R.C. Ward, 1989, “Development of a bacterial transport model for coarse
soils,” Water Resources Bulletin, 25, p. 349.
346
D.S. Chandler, I. Farran, and J.S. Craven, 1981, “Persistence and distribution of pollution
indicator bacteria on land used for disposal of piggery effluent,” Applied and Environmental
Microbiology, 42, p. 453.
347
R.W. Lindenstruth and B.Q. Ward, 1948, “Viability of Vibrio fetus in hay, soil and manure,”
Journal of the American Veterinary Medical Association, 113, p. 163.
148
Walkerton Inquiry Commissioned Paper 6
One area of concern is manure from animals routinely treated with antibiotics.
Current research in Ontario has failed to identify increased antibiotic resistance
in bacteria from fields regularly augmented with this manure.348 This suggests
that, if manure is properly applied, land application does not pose an additional
threat to water resources from antibiotic-resistant bacteria.
3.2.7.5 Viruses
Viruses near the soil surface are rapidly inactivated by the combination of stresses
imposed by sunlight, soil drying, predation, and other soil-based factors such
as pH. Kowal reviewed the literature on virus survival.349 Moisture content
appears to be a major factor once the virus has penetrated the soil surface.
About 100 days is the longest survival time of enteric viruses.
Figure 3-4 Survival of E. coli O157:H7 in Soils of Different Texture
8.0
Sandy soil
Loam soil
log10 cfu/g soil
6.0
Clay
4.0
2.0
1.0
0
5
10
15
20
25
30
Time (weeks)
Source: Redrawn from D.R. Fenlon, I.D. Ogden, A. Vinten, and I. Svoboda, 2000, “The fate of Escherichia coli and
E. coli O157 in cattle slurry after application to land,” The Society for Applied Microbiology, 88, p. 149S.
348
E. Topp, 2000, [personal communication].
N.E. Kowal, 1985, Health Effects of Land Application of Municipal Sludge (Triangle Park, NC:
Health Effects Research Laboratory, Office of Research and Development, U.S. Environmental
Protection Agency).
349
The Management of Manure in Ontario with Respect to Water Quality
149
The movement of viruses from manure in surface runoff has not received
significant attention. Movement to groundwater has been investigated in model
systems or has been inferred from studies on wastewater application. Penetration
of virus particles was deeper in sandy soil (with movement to 17.4 m) than in
loamy or clay soils. It was also greater under conditions of saturated flow than
under unsaturated flow.350
3.2.7.6 Endocrine-disruptive compounds
The fate of estradiol-17β excreted onto Kentucky bluegrass bedding by mares
between 12 and 16 weeks gestation was investigated by Busheé et al.351 The
concentration of estradiol-17β was 35.1 µg/kg in the bedding, almost 7 times
greater than the value found in municipal sewage sludge (5.2 µg/kg). However,
the water content of the sewage sludge (80%) was much greater than that of
the bedding (7%), so on a dry-weight basis the differences were much less (40
µg/kg and 30 µg/kg, respectively). The bedding material was applied to a tall
fescue pasture at a rate of 9.1 t/ha, providing an equivalent of approximately
100 kg/ha N. The pasture was then irrigated to generate runoff. The average
concentration of estradiol-17β in the runoff (adjusted for flow) was 0.6 µg/L.
In a similar experiment, litter from a broiler chicken barn was applied at rates
of 1.76–7.05 t/ha.352 The estradiol-17β concentration in the litter was 131 µg/
kg (dry-weight basis). Concentrations of estradiol-17β in runoff ranged from
0.2 to 1.3 µg/L. Pretreatment with alum (aluminium sulphate) increased the
acidity of the manure and reduced the concentration of estradiol-17β in runoff
from the poultry litter by 40%, but had no effect on the hormone in the horse
bedding runoff, perhaps because of inadequate mixing.
Once incorporated into the soil, natural hormones in the manure do not appear
to persist. They may be readily broken down by soil microbes,353 but Shore et al.
350
J.C. Lance and C.P. Gerba, 1984, “Virus movement in soil during saturated and unsaturated
flow,” Applied and Environmental Microbiology, 47, p. 335; J.C. Lance, C.P. Gerba, and D.S. Wang,
1982, “Comparative movement of different enteroviruses in soil columns,” Journal of Environmental
Quality, 11, p. 347.
351
E.L. Busheé, D.R. Edwards, and P.A. Moore, 1998, “Quality of runoff from plots treated with
municipal sludge and horse bedding,” Transactions of the American Society of Agricultural Engineers,
41, p. 1035.
352
D.J. Nichols, T.C. Daniel, P.A. Moore, D.R. Edwards, and D.H. Pote, 1997, “Runoff of estrogen
hormone 17-Estradiol from poultry litter applied to pasture,” Journal of Environmental Quality,
26, p. 1002.
353
Topp, 2000.
150
Walkerton Inquiry Commissioned Paper 6
suggested that physicochemical processes were important.354 However, five months
after the application of manure from broiler chickens containing 0.03 µg/g
testosterone and 0.03 µg/g estrogen, no estrogen could be identified in soil to
which manure had been applied 5 months earlier, but testosterone was present.355
3.2.7.7 Summary
Some of the NH4+ in manure can be taken up directly by the crop or may be
nitrified to the much more mobile NO–3 form, which can also be used by the
crop. The aim of the producer is to have the crop remove as much of these
mineral-N forms as possible from the soil. Some of the NO–3 may undergo
denitrification to N2O or even N2 gas. The additional organic carbon applied
in manure increases the likelihood of N being lost by denitrification. However,
NO–3 in the soil is at risk of leaching when rainfall exceeds the transpiration of
water by the crop and evaporation from the soil.
The P content of manure can be in mineral or organic form. In liquid manure
the larger fraction is in mineral form. The amount of P available to a crop in
the year of application is still in dispute, but over successive years, all eventually
becomes available. Much of the P applied is found as crystals or precipitates, so
is largely immobile within the soil profile.
Cu and Zn tend to accumulate in soils given regular applications of manure.
Acidification of the soil tends to increase their mobility, but in Ontario’s
calcareous soils this is not considered a major threat to water resources.
Bacteria can survive longer in cold soils than in warm soils, and longer in finetextured than in coarse-textured soils. Biological as well as physical factors
influence the survival. There is no evidence that bacteria in soils subject to
regular manure applications have developed more antibiotic resistance because
of the feeding of subtherapeutic antibiotic doses to enhance growth of livestock
and poultry.
Estrogenic endocrine-disrupting compounds in manure do not appear to persist
in soil.
354
355
Shore, Correll, and Chakraborty, 1995.
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
151
3.2.8 Contamination of water resources
The majority of research to date has failed to quantify the maximum manure
loading that does not cause a negative environmental impact. For example, an
application of 36,000 L/ha of manure had a more deleterious impact on water
quality than did an application of 140,700 L/ha.356
3.2.8.1 Nitrate
There is little information available for Ontario on the impact of manure
application on nitrate leaching. In part this is because the potential for animal
manure to contaminate groundwater with nitrate is difficult to determine due
to:
•
•
•
the possible losses by NH3 volatilization,
the need for the ammoniacal and organic forms of nitrogen to be converted
to the more mobile NO–3 form, and
the other possible transformations of NO–3.
For example, after a heavy application of slurry to light-textured soil, a significant
amount could not be accounted for in either the soil or drainage water.357 The
nitrate in the drainage water was less than 1% of the total N applied. Nonetheless,
the average nitrate concentrations in tile-drainage water from land receiving swine
manure was 26.5 mg/L N (from five swine farms), significantly greater than the
13.8 mg/L N measured for 15 cash-crop farms.358 Nitrate levels in the shallow
groundwater were also significantly higher for manured fields (5.77 mg/L N)
compared with non-manured fields (2.46 mg/L N). One reason for greater nitrate
leaching from manured land than from land on which mineral fertilizer is applied
could be that producers make no allowance for the mineralization of the organic
nitrogen in the manure.359
356
D.M. Dean and M.E. Foran, 1991, The Effect of Farm Liquid Waste Application on Receiving
Water Quality. Final Report RAC Projects 430G and 512G (Exeter, ON: Ausable-Bayfield
Conservation Authority).
357
Burford, Greenland, and Pain, 1976.
358
Fleming, MacAlpine, and Tiffin, 1998.
359
I.K. Thomsen, J.F. Hansen, V. Kjellerup, and B.T. Christensen, 1993, “Effects of cropping
system and rates of nitrogen in animal slurry and mineral fertilizer on nitrate leaching from a
sandy loam,” Soil Use and Management, 9, p. 53.
152
Walkerton Inquiry Commissioned Paper 6
The changes in soil structure resulting from reduced tillage may modify
significantly the impacts of agricultural practices on the environment. In particular,
the consequences for manure application need to be considered. The reduction
in air-filled porosity can limit the volume of liquid manure that could be applied
without inducing drain flow because of a greater likelihood of transport through
macropores. Consequently, the potential for nitrate contamination of groundwater
and bacterial contamination of rivers could increase.360 However, Beven and
Germann suggested that macropores do not always increase infiltration because
water may move from these pores into the soil matrix, but at a slightly deeper
depth in the soil rather than at the soil surface.361
3.2.8.2 Phosphorus
Some 10 years ago, phosphorus contribution to surface water in runoff from
agricultural land was the major focus of the Federal-Provincial Soil and Water
Environmental Enhancement Program (SWEEP). Studies during the 1970s
under the Pollution from Land Use Activities Reference Group (PLUARG)
of the International Joint Commission for the Great Lakes (IJC) showed
that runoff from agricultural land was responsible for about 70% of the
phosphorus reaching Lake Erie from the tributaries in Ontario.362 About
20% of this amount (15% of the total) was estimated to be due to direct
inputs from livestock operations, including runoff from storage areas and
surface runoff from manure applied close to streams and not incorporated.
The remainder was due largely to phosphorus associated with eroded
sediment. Manure application may have two opposing effects on this latter
contribution: it increases the P-content of the soil and hence the concentration
on the eroded sediment, while on the other hand manure tends to improve
soil structure and hence reduce erosion.
One poorly understood aspect of phosphorus in runoff is the bioavailability of
different forms of phosphorus.363 While manure application may not increase
the total phosphorus in runoff, it may increase the amount of bioavailable
360
Dean and Foran, 1991.
K. Beven and P. Germann, 1982, “Macropores and water flow in soils,” Water Resources Research,
18, p. 1311.
362
M.H. Miller, J.B. Robinson, D.R. Coote, A.C. Spires, and D.W. Draper, 1982, “Agriculture
and water quality in the Canadian Great Lakes Basin: III. Phosphorus,” Journal of Environmental
Quality, 11, p. 487.
363
Sharpley et al., 1992
361
The Management of Manure in Ontario with Respect to Water Quality
153
phosphorus. In Delaware, continual land application of animal manures has
resulted in an accumulation of P in the surface soil.364 These authors concluded
that the bioavailability of P in runoff water from land following manure
application increased because of the increased transport of low-density organic
material together with the high solubility of manure-P. The magnitude of the
increase would be expected to vary, depending on the density of the manure,
the water, and P-content, for different animal sources.365 There is some evidence
that P in the manure from animals fed HAP corn (see section 3.2.1) is more
bioavailable than that from conventionally fed animals.366
Although the phosphorus leaching is considered less important than the leaching
of nitrate, particularly with respect to water resources used for drinking water
supplies, the right combination of agricultural management practices, soil
properties, and climatic conditions can lead to significant losses of solubleand particulate-P through leaching.367
3.2.8.3 Bacteria
The Ontario Farm Groundwater Quality Survey found that the proportion of
wells contaminated with bacteria was significantly greater on farms where
manure was spread than where only mineral fertilizers were used.368 Soil type
was important in this result: less contamination resulted under coarse, gravelly
soils and fine-textured soils than under loams.369 The results of the Ontario
Farm Groundwater Quality Survey showed that contamination of drinkingwater wells was similar to that under fields where the farmers were carrying out
their normal cropping practices.370 This clearly indicated that groundwater
could be contaminated by bacteria moving through the soil, rather than by
surface water entering poorly-maintained wells. Evidence of repeated
364
A.N. Sharpley and A.D. Halvorson, 1994, “The management of soil phosphorus availability
and its impact on surface water quality,” Advances in Soil Science: Soil Processes and Water Quality,
R. Lal and B.A. Stewart (eds.), (Boca Raton, FL: CRC Press), p. 7.
365
Ibid.
366
J.S. Paschold, B.J. Wienhold, and R. Ferguson, 2000, “Crop utilization of N and P from soils
receiving manure from swine fed low phytate and traditional corn diets,” Annual Meeting Abstracts,
ASA, CSSA, SSSA, Minneapolis, Minnesota, Nov. 5–9, p. 352.
367
J.T. Sims, R.R. Simard, and B.C. Joern, 1998, “Phosphorus loss in agricultural drainage: Historical
perspective and current research,” Journal of Environmental Quality, 27, p. 277.
368
Rudolph, Barry, and Goss, 1998.
369
Goss, Barry, and Rudolph, 1998.
370
Rudolph, Barry, and Goss, 1998.
154
Walkerton Inquiry Commissioned Paper 6
groundwater contamination has been observed under land where manure was
regularly applied (figure 3-5).
Liquid manure adversely affected tile-water quality when applied to the land
following the current farming guidelines. Of the manure spreading events
investigated, 75% resulted in water quality impairment.371 Bacteriological
contamination from tile drains can be greater after injection than after surface
spreading.372 It is difficult to determine an acceptable rate of liquid manure
application, due to the numerous factors which affect the contamination of
watercourses.373 The importance of soil macropores for the rapid transport of
bacteria to tile drains was highlighted in their studies.
The likelihood of bacteria moving into water resources declines with time after
manure application because the organisms die off, but this takes longer in
manure applied in late fall, shortly before freeze-up. Application as a sidedressing for corn (which generally occurs in mid-June, when soils are relatively
Figure 3-5 Presence of Fecal Coliforms in Test Wells
Fecal coliforms (cfu/100 mL)
150
100
50
0
9
12
13
03-03-97
23-04-97
10-9-97
Dean and Foran, 1991.
Ibid.
373
Foran, Dean, and Taylor, 1993.
372
21
19-02-97: before chlorination
Source: Goss and Unc, unpublished.
371
16
22
The Management of Manure in Ontario with Respect to Water Quality
155
dry and warm) results in the shortest period of survival. Later applications
might further reduce the likelihood of bacterial contamination, but increase
the risk of nitrate contamination of groundwater because the crop has
insufficient time to acquire the nutrient from the soil.
Thelin and Gifford showed that if a sample of freshly voided manure was subject
to water from a rainfall simulator within 5 days, the concentration of fecal
coliform bacteria in runoff was in the order of 104/mL, but this number declined
to 400/mL after 30 days.374
3.2.8.4 Endocrine-disruptive compounds
Most studies have only reported the transport of the natural hormones from
manure in surface runoff. The most detailed investigation375 showed that the
concentration of estradiol-17β (y µg/L) in runoff was related to the rate of
broiler chicken litter application rate (x t/ha) by the equation:
y = –0.0096 + 0.1674x
(1)
The concentration of estradiol-17β in runoff from litter left on the surface for
7 days was only 10% of that from the freshly applied litter. Shore et al. reported
that surface runoff from fields receiving broiler chicken manure contained 14
to 20 ng/L estrogen and 0.9 to 34.2 ng/L testosterone.376 Levels of natural
hormones above 10 ng/L in water can have measurable effects on both plants
and animals.377
Servos et al. reported the detection of endocrine-disruptive compounds in tiledrainage water, indicating that they may also be moving directly into the tile
drains through preferential flow paths.378
374
R. Thelin and G.F. Gifford, 1983, “Fecal coliform release patterns from fecal material of cattle,”
Journal of Environmental Quality, 12, p. 57.
375
Nichols et al., 1997.
376
Shore, Correll, and Chakraborty, 1995.
377
Ibid.
378
M. Servos, K. Burnison, S. Brown, T. Mayer, J. Sherry, M. McMaster, G. Van Der Kraak, R. McInnis,
J. Toito, A. Jurkovic, D. Nuttley, T. Neheli, M. Villella, T. Ternes, E. Topp, and P. Chambers, 1998,
“Runoff of estrogens into small streams after application of hog manure to agricultural fields in southern
Ontario,” 19th Annual Meeting of the Society of Environmental Toxicology and Chemistry, Charlotte, NC,
Nov. 15–19.
156
Walkerton Inquiry Commissioned Paper 6
Estrogens may bind to soil more readily than testosterone and in consequence
may be more likely to leave manured field in surface runoff. Testosterone may
be more readily leached, and may explain the presence of at least ten-times
more testosterone (1 ng/L) than estrogen (<0.1 ng/L) in water from a well on
a farm applying chicken manure to the land.379
3.2.8.5 Summary
Little information is available for Ontario on the impact of manure application
on nitrate leaching. Nitrate leaching can be greater from manured land than
from land receiving mineral fertilizer. However, this could be because
producers are uncertain about making any allowance for the mineralization
of the organic nitrogen in the manure. Tillage may affect the potential for
leaching of NO3–, resulting in greater losses with no-till, but evidence is lacking
for Ontario.
Manure applications increase the P-content of the soil and hence the
concentration on the eroded sediment. However, manure also tends to improve
soil structure and hence reduce erosion.
A major problem is associated with applying manure to land with tile drains.
After liquid manure application, bacteria move rapidly to the tile drains if the
soil is close to field capacity.
The likelihood of bacteria moving into water resources declines with time
because the organisms die off. The shortest period of survival would be expected
for bacteria in the summer-applied manure. However, manure applications
later than the time of side-dressing for corn might reduce the likelihood of
bacterial contamination, but increase the risk of nitrate contamination
of groundwater.
Endocrine-disruptive compounds are found in runoff from land with manure
on the surface as well as in tile-drain discharge, and at concentrations that are
considered appreciable.
379
Shore, Correll, and Chakraborty, 1995.
The Management of Manure in Ontario with Respect to Water Quality
157
3.3 Transport Processes
Substances in manure move to water resources by a variety of transport processes,
reviewed in this section.380 Contaminants originating in manure that affect
water resources can be divided into three basic classes:
•
•
•
simple inorganic ions (e.g., NH4+, NO–3, H2PO4+),
more complex organic molecules (e.g., phytates and endocrine-disrupting
substances), and
particulates (e.g., microorganisms).
The concentration of simple inorganic ions is controlled by the equilibrium
between the solids and their solution phases in soil water. This may involve the
formation of sparingly soluble precipitates and adsorption reactions with soil
particles. For organic molecules and some inorganic species such as NH4+, the
final concentration of contaminants in soil water depends on their vapour
pressure and their solubility in water and in soil organic matter. In contrast,
particulates are generally affected by surface charge. In all cases, transport varies
greatly depending on soil structure, especially the size distribution and continuity
of soil pores. For inorganic nitrogen compounds and bacteria, the soil is itself
a source and may also contain one or more sinks.
3.3.1 Water partitioning at the soil surface
As water is the primary factor determining the movement of contaminants, its
partitioning at the soil surface into runoff and infiltration (drainage) is of
fundamental importance. During precipitation (rainfall or irrigation), the surface
of the soil becomes wet and water starts to move down through the soil. If the
rate of precipitation exceeds the ability of the soil to transmit water to its depths,
ponding occurs. Ponding allows water to fill very large pores at the soil surface,
therefore promoting preferential flow (flow in areas of the soil that offer the least
resistance – see section 3.3.4). On land with any slope, the depth of ponding is
likely to be very small before the water starts to flow down the slope. The rate of
flow of surface runoff can be slowed by crop residues and soil clods. As the flow
380
For comprehensive reviews of solute transport, readers are referred to T.M. Addiscott and R.J.
Wagenet, 1985, “Concepts of solute leaching in soils: A review of modelling approaches, “ Journal
of Soil Science, 36, p. 411; and N.J. Jarvis, P.E. Jansson, P.E. Dik, and I. Messing, 1991, “Modelling
water and solute transport in macroporous soil. I. Model descriptions and sensitivity analysis,”
Journal of Soil Science, 42, p. 59.
158
Walkerton Inquiry Commissioned Paper 6
slows, the depth of water increases or the ponded area gets larger. In either case it
enhances infiltration into the soil and restricts transport off the field.
Increased infiltration into vegetated buffer strips also increases their efficiency
of contaminant removal from surface runoff.381 All fecal coliform bacteria were
removed by passage through a 6.1-m vegetated buffer strip, although
concentrations of sediment, organic-N, NH4+-N, and ortho-phosphate were
reduced by only about 70%. Preferential infiltration by the bacteria was cited
as the reason for the difference.382
Manure can affect the partitioning of water in the period immediately after land
application, but the direction of the change depends on both the manure type
and the soil type. In coarse-textured soils, there is no effect because rainfall intensity
is not likely to exceed the infiltration rate. In loamy and finer-textured soils, the
application of dilute liquid manure can both encourage surface runoff and enhance
Figure 3-6 Partitioning of Precipitation into Surface Runoff and Drainage
after the Application of Liquid Swine or Solid Beef Manure
Runoff
Loam/Sandy Loam
Loam/Silt Loam
(0–50 cm profile)
(0–100 cm profile)
+20
+10
0
Soil depth –10
(mm)
–20
–30
Drainage
–40
Liquid swine manure
–50
Solid beef manure
0.24
0.25
0.34
0.35
0.24
0.24
0.32
0.34
Soil volumetric water content
Note: In general, the application of liquid manure resulted in more drainage than did solid manure. In the finertextured material, liquid manure also promoted more surface runoff.
Source: After A. Unc and M.J. Goss, 2000, “Effect of manure application on soil properties relevant to bacterial
transport,” Paper presented at the ASA, CSSA, SSSA Annual Meetings, 5–9 Nov 2000, Minneapolis, Minnesota
(Madison, WI: American Society of Agronomy).
381
M.S. Coyne, R.A. Gilfillen, A. Villalba, Z. Zhang, R. Rhodes, L. Dunn, and R.L. Blevins,
1998, “Fecal bacteria trapping by grass filter strips during simulated rain,” Journal of Soil and
Water Conservation, 53, p. 140.
382
T.T. Lim, D.R. Edwards, S.R. Workman, B.T. Larson, and L. Dunn, 1998, “Vegetated filter
strip removal of cattle manure constituents in runoff,” Transactions of the American Society of
Agricultural Engineers, 41, p. 1375.
The Management of Manure in Ontario with Respect to Water Quality
159
preferential flow. Until solid manure has been incorporated, it acts as a mulch
and encourages infiltration rather than surface runoff (figure 3-6).
3.3.1.1 Summary
Conditions at the soil surface affect the partitioning between surface runoff
and drainage. Liquid manure appears to encourage the development of surface
runoff, whereas solid manure encourages drainage. Preferential flow paths are
important for rapid transport.
3.3.2 Basic equations governing transport through the soil
Water movement through the unsaturated zone toward an aquifer can be
described by the Richards equation, assuming one-dimensional flow in a
homogeneous soil:
δθ = δ
δt
δz
K(θ)
δϕ
δz
– U(z,t)
(2)
where
θ
K(θ)
δϕδz
U
z
t
=
=
=
=
=
=
volumetric water content
the water content-dependent hydraulic conductivity
the hydraulic gradient
a sink term covering extraction or uptake of water by plant roots
depth, taken as positive downwards
time
To develop a solvable form of the equation, a term called the hydraulic diffusivity,
D (2), is introduced, defined as:
D(θ) = K(θ)
δϕ
δθ
(3)
where
ϕ
= the matric potential
δϕ/δθ = the slope of the moisture release characteristic curve.
160
Walkerton Inquiry Commissioned Paper 6
Equation 2 becomes:
δϕ
δ
δθ
=
D(θ)
– K(θ) – U(z,t)
δt
δz
δz
(4)
A quantitative description of the transport of contaminants that only dissolve
in water usually assumes the convection-dispersion equation (CDE):
qs = qwCl – De
dCl
dC
– Dh l
dz
dz
(5)
where
qs
Cl
De
Dh
qw
= the mass of the solute moving through unit-cross-sectional area
per unit time
= the concentration of the solute in the soil water
= the effective diffusion coefficient of the solute in the soil, adjusted
for the water content and tortuosity of the pore system
= the mechanical dispersion coefficient that includes the effect of
local variation in the velocity of water in large and small pores
= the water flux density
Thus, the transport of contaminants depends on factors governing their
concentration in the soil solution and the flux of water available to move them.
If a contaminant undergoes transformations in the soil, is subject to die-off, or
is absorbed by plants, additional sink terms have to be added to the continuity
equation, as in equation 2. Further refinements are needed to include exchange
of a contaminant between the liquid and solid phases in the soil.
3.3.2.1 Summary
Basic equations, which describe the movement of water and pollutants through
soil, highlight the importance of the concentration of a potential contaminant in
the soil solution and the amount of water available to move it. To provide an
adequate description of the movement, knowledge is needed of other sources of
the contaminant in the soil, any potential sinks, and factors affecting its survival.
The Management of Manure in Ontario with Respect to Water Quality
161
3.3.3 Contaminant characteristics relevant to their transport
It is important to consider the features of different contaminants that affect
their transport. Nitrate travels in solution with infiltrating water. Plant uptake
and denitrification remove nitrate from solution, but these processes are likely
less important when infiltration is rapid. Once nitrate enters a preferential
flow path, there is little chance of it being removed from solution. In contrast,
NH4+ and H2PO4+ can be removed from the water through interaction with the
soil matrix.
Volatile organic compounds can also move as vapours, so additional terms
must be added in the equations given in section 3.3.2 to take account of the
diffusive and dispersive fluxes in this phase. Although NH3 can form from
NH4+ and then be lost by volatilization, it may also move in the gaseous phase
within the soil. As already described, much of the ammoniacal nitrogen present
in the manure shortly after excretion may be lost to the atmosphere before
field application. Another feature is the variation in N-deposition from the
atmosphere. The considerable variation between monitoring sites observed in
studies of N-deposition from the atmosphere383 may be due to the impact of
ammonia volatilization from livestock operations.384
Transport of particulates such as microorganisms follows that of colloids,
although viruses exhibit little filtration and are adsorbed onto low-molecularweight organic molecules in soil.385 It is reasonable to assume that the
concentration of a solute will tend to become uniformly distributed within
each pore space, but this may not be true of colloids. Bacteria are much larger
than nitrate ions and their movement is more likely to be affected by the flow
associated with the pore size in which they are transported. They have variable
surface charge which allows stronger adsorption of the bacteria to soil particles.
Bacteria also have very large surface-area-to-volume ratios that provide a large
proportion of sites for adsorption. A third consideration with microorganisms
is that their populations are dynamic. They are alive and influenced by factors
that affect their survival. Many are also motile.
383
D.A.J. Barry, D. Goorahoo, and M.J. Goss, 1993, “Estimation of nitrate concentration in
groundwater using a whole farm nitrogen budget,” Journal of Environmental Quality, 22, p. 767.
384
M.J. Goss, E.G. Beauchamp, and M.H. Miller, 1995b, “Can a farming systems approach help
minimize nitrogen losses to the environment?” Journal of Contaminant Hydrology, 20, p. 285.
385
Kowal, 1985.
162
Walkerton Inquiry Commissioned Paper 6
3.3.3.1 Summary
It is not sufficient to describe the transport of contaminants in the water phase
without first identifying other factors that can affect mobility.
3.3.4 Preferential flow and solute transport
Soil pore characteristics are important for transport. However, the transport of
contaminants in soils with strongly aggregated structures or with large and
continuous pores is not well described by models based on equation 5, because
preferential flow occurs.386
Preferential flow is the process whereby water, and materials contained in it,
move by preferred pathways through a porous medium. This means that part
of the matrix is effectively bypassed. The term preferential flow does not itself
convey a mechanism for the process,387 whereas the often-used “macropore
flow” implies transport through relatively large pores, channels, fissures, or
other semi-continuous voids within the soil. Although there is no standardized
definition for macropores, some pore classification has been proposed.
Luxmoore suggested the classes of micro-, meso-, and macropore, defined by
equivalent pore diameters of less than 10 µm, 10 to 1000 µm, and more than
1000 µm (1 mm), respectively.388 Skopp defined macroporosity as that pore
space which provides preferential paths of flow so that mixing and transfer
between such pores and the remaining pore space is limited.389 Some other
classifications of soil pore size and their functions with respect to water
movement or root penetration have been summarized by Helling and Gish.390
Pore size and the corresponding capillary potential was given by Beven and
Germann.391
386
G.W. Thomas and R.E. Phillips, 1979, “Consequences of water movement in macropores,”
Journal of Environmental Quality, 8, p. 149; R.J. Wagenet, 1990, “Quantitative prediction of the
leaching of organic and inorganic solutes in soil,” Philosophical Transactions of the Royal Society of
London Series B, Biological Sciences, 329, p. 321.
387
C.S. Helling and T.J. Gish, 1991, “Physical and chemical processes affecting preferential flow,”
Preferential Flow, T.J. Gish and A. Shrimohammadi (eds.), (St. Joseph, MI: American Society of
Agricultural Engineers), p. 77.
388
R.J. Luxmoore, 1981, “Micro-, meso-, and macroporosity of soil,” Soil Science Society of America
Journal, 45, p. 671.
389
J. Skopp, 1981, “Comment on ‘Micro-, meso-, and macroporosity of soil,’” Soil Science Society
of America Journal, 45, p. 1246.
390
Helling and Gish, 1991.
391
Beven and Germann, 1982.
The Management of Manure in Ontario with Respect to Water Quality
163
Macropores may develop by physical (e.g., swell-shrink, freeze-thaw, or tillage)
or biological (e.g., burrowing by earthworms, insects, and other soil fauna or
the growth of roots) processes in the soil. Continuous macropores can be formed
by the activity of soil macro-fauna, especially earthworms.392 In soils with
significant swell-shrink behaviour, cracking may be important in the
development of a preferential flow domain, and the extent of crack development
is generally related to water extraction by roots. The channels created by roots
can also dominate the transport process once the original roots have decayed.393
Freeze-thaw cycles may also result in fractures.
The installation of tile drains also provides some continuous porosity between
the soil surface and the drain. The macropores therefore provide a rapid conduit
between the field and the surface water body into which the tile drains discharge.
Macropore flow allowed manure liquids to move into subsurface drains within
an hour after application.394
The essential feature of preferential flow is that percolating water can bypass a
large fraction of the soil matrix, thus moving deeper and with less displacement
of the initial soil solution than would have been predicted by piston
displacement.395 Watson and Luxmoore found that under ponded conditions,
73% of the flux was conducted through macropores (pore diam. >1 mm).396
Furthermore, they estimated that 96% of the water was transmitted through
only 0.32% of the soil volume. As much as 70–90% of applied chemicals may
be moving preferentially through macropores.397
392
W. Ehlers, 1975, “Observations on earthworm channels and infiltration on tilled and untilled
loess soil,” Soil Science, 119, p. 242.
393
K.P. Barley, 1954, “Effects of root growth and decay on the permeability of a synthetic sandy
loam,” Soil Science, 78, p. 205.
394
Fleming and Bradshaw, 1991, 1992a, 1992b.
395
Beven and Germann, 1982; J. Bouma, 1981, “Soil morphology and preferential flow along
macropores,” Agricultural Water Management, 3, p. 235; V.L. Quisenberry and R.E. Phillips, 1976,
“Percolation of surface-applied water in the field,” Soil Science Society of America Journal, 40, p. 484;
V.L. Quisenberry and R.E. Phillips, 1978, “Displacement of soil water by simulated rainfall,” Soil
Science Society of America Journal, 42, p. 675; V.L. Quisenberry, B.R. Smith, R.E. Phillips, H.D. Scott,
and S. Nortcliff, 1993, “A soil classification system for describing water and chemical transport,” Soil
Science, 156, p. 306; A. Shirmohammadi, T.J. Gish, A. Sadeghi, and D.A. Lehman, 1991, “Theoretical
representation of flow through soils considering macropore effect,” Preferential Flow, T.J. Gish and
A. Shirmohammadi (eds.), (St Joseph, MI: American Society of Agricultural Engineers), p. 233.
396
K.W. Watson and R.J. Luxmoore, 1986, “Estimating macroporosity in a forest watershed by use
of a tension infiltrometer,” Soil Science Society of America Journal., 50, p. 578.
39 7
L.R. Ahuja, B.B. Barnes, and K.W. Rojas, 1993, “Characterization of macropore transport studied
with the ARS root zone water quality model,” Transactions of the American Society of Agricultural
Engineers, 36, p. 396.
164
Walkerton Inquiry Commissioned Paper 6
Preferential flow may occur even in coarse-textured soils that are considered to
be homogeneous.398 Macropore flow commenced at the tilled-untilled boundary
in a cultivated Maury silt loam399 and in a Cecil sandy clay loam in the Piedmont
of South Carolina.400
Transport of bacteria is concentrated in regions of preferential flow. Unc and
Goss applied liquid swine manure to an undisturbed column of clay-loam soil.401
They found that about 90% of bacteria moved through only 15% of the available
cross-sectional area. The same proportion from solid beef manure were transported
through less than 25% of the cross-sectional area of soil (figure 3-7).
Jardine et al. found that solutes were transported by convection and diffusion from
small-pore to large-pore regions in undisturbed soil as a result of hydraulic and
Figure 3-7 Evidence for Preferential Movement of E. coli Bacteria from
Manure Applied to a Column of Clay-loam Soil
100
Percentage of bacteria transported
80
60
Liquid swine manure
Solid beef manure
40
20
0
0
10
20
30
40
50
60
Percentage area
Source: Unc and Goss, 2000.
398
K.J.S. Kung and S.V. Donohue, 1991, “Improved solute-sampling protocol in a sandy vadose
zone using ground-penetrating radar,” Soil Science Society of America Journal, 55, p. 1543; M.S.
Andreini, J.-Y. Parlange, and T.S.Steenhuis, 1990, “A numerical model for preferential solute
movement in structured soils,” Geoderma, 46, p. 193.
399
Quisenberry and Phillips, 1976.
400
W.A. Hatfield, 1988, Water and Anion Movement in a Typic Hapludult, Ph.D. dissertation,
Clemson Univ. Clemson, SC.
The Management of Manure in Ontario with Respect to Water Quality
165
concentration gradients, respectively.402 Small pores were a major source of the
solute transported rapidly by large pores. A diffusion-based mechanism described
by Luxmoore,403 in which new water entering a soil gains the chemical attributes of
old water, could explain the results reported by Jardine et al.404 According to
Luxmoore, a large surface area of interaction, combined with a short diffusion path
between mesopore channels and micropores, allows diffusion to be a significant
contributor to chemical transport during preferential flow events.405
Whether macropore flow increases or decreases, the residence time of solutes
in soil, including those in manure, depends on the location of solutes relative
to the macropores.406 However, macropore flow has been shown to be a major
factor in groundwater contamination. For example, leaching of nitrate added
to the soil surface as fertilizer was more rapid than leaching of nitrate formed
by mineralization of organic matter within soil aggregates.407
The rainfall pattern after manure application is critical for the subsequent
movement of solutes. An initial small rain (5–10 mm) may move the solute
into the soil matrix, thereby reducing the potential for transport in macropores
during subsequent rainfall events.408
401
A. Unc and M.J. Goss, 2000, “Effect of manure application on soil properties relevant to bacterial
transport,” Paper presented at the ASA, CSSA, SSSA Annual Meetings, 5–9 Nov. 2000, Minneapolis,
Minnesota (Madison, WI: American Society of Agronomy).
402
P.M. Jardine, G.V. Wilson, and R.J. Luxmoore, 1990, “Unsaturated solute transport through a
forest soil during rain storm events,” Geoderma, 46, p. 103.
403
R.J. Luxmoore, 1991, “On preferential flow and its measurement,” Preferential Flow, T.J. Gish and
A. Shrimohammadi (eds.), (St. Joseph, MI: American Society of Agricultural Engineers), p. 113.
404
Jardine, Wilson, and Luxmoore, 1990.
405
Luxmoore, 1991.
406
A. Wild, 1972, “Nitrate leaching under bare fallow at a site in northern Nigeria,” J. Soil Science,
23, p. 315; D.R. Edwards, V.W. Benson, J.R. Williams, T.C. Daniel, J. Lemunyon, and R.G. Gilbert,
1994, “Use of the EPIC model to predict runoff transport of surface-applied inorganic fertilizer and
poultry manure constituents,” Transactions of the American Society of Agricultural Engineers, 37, p. 403;
S. Chen, R.E. Franklin, and A.D. Johnson, 1997, “Clay film effects on ion transport in soil,” Soil
Science, 162, p. 91; S. Chen, R.E. Franklin, V. Quisenberry, and P. Dang, 1999, “The effect of
preferential flow on the short and long-term spatial distribution of surface applied solutes in a structured
soil,” Geoderma, 90, p. 229.
407
Wild, 1972; M.J. Goss, P. Colbourn, G.L. Harris, and K.R. Howse, 1987, “Leaching of nitrogen
under autumn-sown crops and the effects of tillage,” Nitrogen Efficiency in Agricultural Soils. EEC
Seminar, D. S. Jenkinson and K. A. Smith (eds.), Edinburgh, September 1987 (London: Elsevier
Applied Science), p. 269.
408
M.J. Shipitalo, W.M. Edwards, W.A. Dock, and L.B. Owens, 1990, “Initial storm effects on
macropore transport of surface-applied chemicals in no-till soil,” Soil Science Society of America Journal,
54, p. 1530; M.H. Golabi, D.E. Radcliffe, W.L. Hargrove, and E.W. Tollner, 1995, “Macro effects in
conventional tillage and no-tillage soils,” Journal of Soil and Water Conservation, 50, p. 205.
166
Walkerton Inquiry Commissioned Paper 6
The initial location of potential contaminants in the soil may affect their
movement.409 Materials at the soil surface may move into macropores open at
the soil surface, and then downward through the topsoil and subsoil to the
water table. However, material that has been incorporated into large soil
aggregates within the topsoil may be protected from being leached by
macropores because most water will move in these pores and bypass the
aggregates rather than move through them.
Initial soil moisture content and rainfall intensity and duration may affect solute
distribution and movement among small and large pores.410 During high rainfall
intensity (when water application exceeds the soil infiltration rate) or under
conditions of saturated flow, preferential flow can be initiated. Soil morphology,411
clay films,412 and surface condition413 affect water and solute distribution or
transport. Among these factors, those related to pedogenetic processes, such as
soil morphology and structure, require longer time periods to show effects. Other
factors such as moisture content, tillage, and cultural practices may be relatively
transient in their effect. Understanding the effects of these factors on water and
solute transport may ultimately lead to a more reliable prediction of transport
processes in soil414 including the movement of contaminants.415
Helling and Gish described some factors affecting the process of preferential
flow, including soil porosity, pore characteristics, structure, initial moisture content,
and soil management.416 Flow through tubes is proportional to the fourth power
of their radii, therefore drainage is much more rapid through large continuous
macropores than through pores of smaller diameter. Mouldboard ploughing may
destroy the continuity of pores between the plough layer and the deep horizons.
Long-term no-tillage plots, on the other hand, often develop a high density of
continuous, relatively large vertical channels.417 Manure application may
409
Jardine, Wilson, and Luxmoore, 1990; Shipitalo et al., 1990; D.J. Timlin, G.C. Heathman, and
L.R. Ahuja, 1992, “Solute leaching in crop row vs. interrow zones,” Soil Science Society of America
Journal, 56, p. 384; Golabi et al., 1995; Chen, Franklin, and Johnson, 1997; Chen et al., 1999.
410
Jardine, Wilson, and Luxmoore, 1990.
411
Bouma, 1981.
412
Quisenberry et al., 1993; Chen, Franklin, and Johnson, 1997.
413
R.E. Phillips, V.L. Quisenberry, J.M. Zeleznik, and G.H. Dunn, 1989, “Mechanism of water
entry into simulated macropore,” Soil Science Society of America Journal, 53, p. 1629; Quisenberry
et al., 1993.
414
Andreini, Parlange, and Steenhuis, 1990; Ahuja, Barnes, and Rojas, 1993.
415
Quisenberry et al., 1993.
416
Helling and Gish, 1991.
417
Goss et al., 1993.
The Management of Manure in Ontario with Respect to Water Quality
167
encourage the activity of earthworms which may result in a greater continuity of
macropores. Hence, contaminants may break through faster than predicted.418
A relatively large water content at the time of application might result in deeper
movement of contaminants,419 but the opposite effect has also been reported.420
Understanding the mechanism of bypass flow through convection and diffusion
from regions with small pores to those with large pores may help to explain
such differences.
3.3.4.1 Summary
For contaminants in manure, preferential flow is important to their transport
through the soil and hence into water resources.
3.3.5 Transport of contaminants from manure
Little detailed information is available on the transport of contaminants from manure
other than N and P. Nitrogen, phosphorus, and organic compounds from manure
can be removed by surface runoff, affecting surface water quality, and can be leached
from the soil, contaminating groundwater. Runoff generally accounts for only a
small portion of applied-N compared with the leached portion.421 For example,
after two growing seasons, less than 2% of fertilizer-N was lost to runoff whereas
30% had moved below 1 m in the soil.422 The actual proportions of nutrients lost
vary according to cropping practices and the type and timing of manure application.
Sharpley investigated N- and P-runoff on ten Oklahoma soils amended with
poultry litter.423 Increasing the time between litter application and rainfall from
418
E. Munyankusi, S .C. Gupta, J.F. Moncrief., and E.C. Berry, 1994, “Earthworm macropores
and preferential transport in a long-term manure applied Typic Hapludalf,” Journal of Environmental
Quality, 23, p. 733.
419
Quisenberry and Phillips, 1976.
420
R.E. White, J.S. Dyson, Z. Gerstl, and B. Yaron, 1986, “Leaching of herbicides through
undisturbed cores of a structured clay soil,” Soil Science Society of America Journal, 50, p. 277.
421
B. Burgoa, R.K. Hubbard, R.D. Wauchope, and J.G. Davis-Carter, 1993, “Simultaneous
measurement of runoff and leaching losses of bromide and phosphate using tilted beds and simulated
rainfall,” Communications in Soil Science and Plant Analysis, 24, p. 2689.
422
Blevins et al., 1996.
423
A.N. Sharpley, 1997, “Rainfall frequency and nitrate and phosphorus runoff from soil amended
with poultry litter,” Journal of Environmental Quality, 26, p. 1127.
168
Walkerton Inquiry Commissioned Paper 6
1 to 35 days reduced total-N in runoff from 7.54 to 2.34 mg/L, NH4+-N from
5.53 to 0.11 mg/L, dissolved-P from 0.74 to 0.45 mg/L, and bioavailable-P
from 0.99 to 0.65 mg/L. When litter was applied 7 days prior to the first rain,
runoff N- and P-concentrations decreased with each of 10 successive rains.
However, NO–3 concentrations were unaffected by rainfall frequency and timing.
3.3.5.1 Nitrogen
N in manure solids left on the soil surface, or associated with fine particles that
are readily moved during soil erosion, can be lost through surface runoff to a
watercourse. The factors that determine N-loss by erosion are:
•
•
•
the amount of sediment moved,
the N-content of the soil moved, and
the N-content of the manure solids.
N dissolved in runoff water is also subject to loss to surface water. Although this
portion is usually small,424 it is very variable and depends on a number of factors,
such as the degree of soil cover, source of N applied, application rate, and timing
and duration of the application. Surface conditions are also important, and are
affected by slope, soil characteristics, and land management. Finally, runoff is
highly dependent on the intensity of rainfall after application. The largest losses
occur if a soluble-N source is applied to a bare soil surface and a significant
rainfall event occurs soon after application.425 In many cases, most of the dissolvedN is transported into the soil with the initial infiltration that precedes runoff.426
Intensive rainfall shortly after fertilizer application generates the largest loss of
NO–3 in runoff.427 However, in the lower southern coastal plain of the United
States, most of the loss of NO–3 in runoff was from sub-surface flow in the top
30 cm of soil rather than from surface flow. Over a 10-year period, 20% of the N
in the applied fertilizer was lost via surface and subsurface flow.428 This was
424
Blevins et al., 1996; Meisinger and Randall, 1991.
D.R. Edwards and T.C. Daniel, 1993, “Effects of poultry litter application rate and rainfall
intensity on quality of runoff from fescue grass plots,” Journal of Environmental Quality, 22, p. 361;
Sharpley, 1997.
426
Meisinger and Randall, 1991.
427
R.K. Hubbard and R.G. Sheridan, 1983, “Water and nitrate losses from a small upland coastal
plain watershed,” Journal of Environmental Quality, 12, p. 291; Hubbard, Leonard, and Johnson,
1991; Lowrance, 1992.
428
Hubbard and Sheridan, 1983.
425
The Management of Manure in Ontario with Respect to Water Quality
169
comparable with the loss in runoff reported by Edwards and Daniel for conditions
of high rainfall intensity.429 Such results suggest that tile-drainage systems can
greatly reduce groundwater contamination at the expense of surface water
contamination. However, not all drainage water may be intercepted by pipe drains,
even during major flow events, so groundwater contamination is still likely.
The major N species lost by leaching is NO–3. If economically optimum rates of
N are applied to row crops such as corn, NO–3-N losses by leaching from the root
zone may be in excess of 10 mg/L, the maximum acceptable concentration in
drinking water.430 Only when plants were visibly deficient in N were the average
NO–3 concentrations (corrected for flow rate) in the leachate below 10 mg N/
L.431 A study on optimum nitrogen and irrigation inputs for corn found that by
applying urea-based fertilizer at 95% of that required for maximum yield, nitrate
leaching could be reduced by 30 to 40%; and by using a variable deficit trigger
for scheduling irrigation, nitrate leaching could be reduced by 50 to 55%.432 At
equivalent N rates, turkey manure produced equal or better crop yields than urea
applications and NO–3 leaching was equal to or less than that with urea.433 Dairy
manure applied to a corn field resulted in similar or slightly smaller NO–3 loading
than agronomically equivalent rates of fertilizer-N.434 In contrast, Nielsen and
Jensen reported that NO–3-N losses from the rooting zone in soils amended with
liquid manure were greater than those from a similar soil to which the same
amount of N had been applied as inorganic fertilizer.435 Jemison and Fox found
very little difference in NO–3 concentrations or mass of NO–3 leached between
non-manured corn and corn manured at the economically optimum rate.436
The different results for the amount of NO–3 leached following manure applications
highlights the importance of N-transformations, such as mineralization and
denitrification, that influence the availability of nitrate in the soil.
429
Edwards and Daniel, 1993.
J.M. Jemison and R.H. Fox, 1994, “Nitrate leaching from nitrogen B fertilized and manured
corn measured with Zero-tension pan lysimeters,” Journal of Environmental Quality, 23, p. 337;
Toth and Fox, 1998.
431
Jemison and Fox, 1994.
432
B.T. Sexton, J.F. Moncrief, C.J. Rosen, S.C. Gupta, and H.H. Cheng, 1996, “Optimizing nitrogen
and irrigation inputs for corn based on nitrate leaching and yield on a coarse-textured soil,” Journal
of Environmental Quality, 25, p. 982.
433
Ibid.
434
W.E. Jokela, 1992, “Nitrogen fertilizer and dairy manure effects on corn yield and soil nitrate,”
Soil Science Society of America Journal, 56, p. 148.
435
N.E. Nielsen and H.E. Jensen, 1990, “Nitrate leaching from loamy soils as affected by crop
rotation and nitrogen fertilizer application,” Fertilizer Research, 26, p. 197.
436
Jemison and Fox, 1994.
430
170
Walkerton Inquiry Commissioned Paper 6
Loss of N is affected greatly by soil water content.437 Nitrate leaching tends to be
greatest when the soil is wet during the late fall, before the soil freezes, and again in
the early spring. It may be minimized by applying manure during the late spring
and early summer when crops can compete for NO–3 with the smaller volume of
water that moves downward through the unsaturated layers of the soil.438
Alfalfa crops, or including alfalfa in the crop rotation, considerably reduced
the amount of NO–3 leaving a farm in leachate.439 This effect is attributed to a
longer period of evapotranspiration resulting in less drainage, as well as greater
uptake and immobilization of N by the perennial crop. In a dry year when
plant growth and N-uptake are limited and percolation of soil water is negligible,
mineralization continues to occur. Mineral-N accumulates in the soil profile
and will be subject to leaching when precipitation exceeds evapotranspiration.
Large soil pores increase the movement of NO–3 when it is mixed with infiltrating
water. The greater the initial soil water content, the deeper the penetration
within the macropores because less water moves laterally into the micropore
system.440 When the soil water content is close to field capacity, the micropore
space is filled with water and application of more solution, such as liquid manure,
tends to encourage flow in the macropore space.441
Few studies compare the potential for nitrate leaching of different manure
types. Younie et al. found that nitrate leaching was higher where liquid cattle
manure was the source of nitrogen than where solid beef manure was used.442
Ritter et al. studied soil-nitrate profiles under 16 sites, some of which received
fertilizer-N alone or in combination with either broiler manure or liquid swine
manure.443 Although direct comparison of manure types was not made on the
same site, N-application rate was found to be the major determinant of N in
the soil profile. It appears that manure from poultry, cattle, or pig operations
has the potential to contaminate groundwater if it is applied at excessive rates.
437
G.W. Randall and T.K. Iragavarapu, 1995, “Impact of long-term tillage system for continuous
corn on nitrate leaching to tile drainage,” Journal of Environmental Quality, 24, p. 360.
438
P.L. Adams, T.C. Daniel, D.R. Edwards, D.J. Nichols, D.H. Pote, and H.D. Scott, 1994, “Poultry
litter and manure contributions to nitrate leaching through the vadose zone,” Soil Science Society of
America Journal, 58, p. 1206.
439
Toth and Fox, 1998.
440
Beven and Germann, 1982.
441
Unc and Goss, 2000.
442
M.F. Younie, D.L. Burton, R.G. Kachanoski, E.G. Beauchamp, and R.W. Gilham, 1996, Impact
of Livestock Manure and Fertilizer Application on Nitrate Contamination of Groundwater, Final report
for the Ontario Ministry of Environment and Energy, RAC No. 488G.
The Management of Manure in Ontario with Respect to Water Quality
171
Liquid manure adversely affected tile-water quality when applied to the land
following the current Ontario farming guidelines. Dean and Foran found
that 75% of the manure-spreading events they investigated resulted in water
quality impairment.444 It appears difficult to determine an acceptable
application rate of liquid manure due to the numerous factors which affect
the contamination of watercourses.445 Pre-tillage is the management technique
best able to minimize the potential for contamination of tile drains from
liquid manure.446
3.3.5.2 Phosphorus
More P is likely to be lost in surface runoff than by leaching.447 Where liquid
or solid manure was not incorporated after application, the loss of phosphorus
in surface runoff was greater from ploughed soil than from land that was under
no-till. Loss from no-till land was similar to that from land where the manure
had been incorporated after application.448
As P is a reactive ion, soil enrichment generally decreases sharply with depth.
Application of cattle feedlot waste resulted in an increased proportion of
available-P in the first 30 cm, but with little increase below 50 cm.449 Decreasing
enrichment or only slight enrichment with depth does not necessarily indicate
no leaching because the residence time of some drainage water in the subsoil
may have been too short, perhaps because of preferential flow, to allow
adsorption of P onto soil particles.450 Furthermore, some subsoils (e.g., sandy
soils) may have limited capacity to retain P.
443
W.F. Ritter, A.E.M. Chirnside, and R.W. Scarborough, 1990, “Soil nitrate profiles under irrigation
on coastal plain soils,” Journal of Irrigation and Drainage Engineering, 116, p. 738.
444
D.M. Dean and M.E. Foran, 1992, “The effect of farm liquid waste application on tile drainage,”
Journal of Soil and Water Conservation, 47, p. 368.
445
Foran, Dean, and Taylor, 1993.
446
Fleming and Bradshaw, 1992b.
447
A.N. Sharpley and P.J.A. Withers, 1994, “The environmentally-sound management of agricultural
phosphorus,” Fertilizer Research, 39, p. 133; K.A. Smith, A.G. Chalmers, B.J. Chambers, and
P. Christie, 1998, “Organic manure phosphorus accumulation, mobility and management,” Soil
Use and Management, 14, p. 1549.
448
King et al., 1994.
449
L.B. Campbell and G.J. Racz, 1975, “Organic and inorganic P content, movement and
mineralization of P in soil beneath a feedlot,” Canadian Journal of Soil Science, 55, p. 457.
450
A.E. Johnston and P.R. Poulton, 1997, “The downward movement and retention of phosphorus
in agricultural soils,” Phosphorus Loss from Soil to Water, H. Tunney, O.T. Carton, P.C. Brookes,
and A.E. Johnston (eds.), (Wallingford, UK: CAB International), p. 422.
172
Walkerton Inquiry Commissioned Paper 6
Leaching of P from manure may occur in both inorganic and organic forms.451
Complexation of P with mobile organic compounds may favour the deep transport
of P in organic forms even through layers with a great P-adsorption capacity, such
as carbonate soil layers. Experimental results showed that P from mineral fertilizer
did not move under the carbonate layer (0.9 m) of soil even after 40 years of
mineral-P fertilization, while organic-P from manure moved up to 1.8 m.452 The
P-movement in this soil was found to be unaffected by the P-adsorption of the soil.
Phosphorus association with low-molecular-weight organic acids favoured
increased mobility through both decreased adsorption and increased dissolution
of P-compounds leading to greater bioavailability453 and to an enhanced risk
of leaching. Increasing labile, weakly bound-P results in a greater vulnerability
of manure-treated soils to lose phosphorus by leaching.454 This results in deeper
penetration of P-compounds after manure application.455
Leaching of P from soil in water-soluble and particulate forms is enhanced by
the presence of tile drainage.456 If a critical concentration of soluble-P in the
ploughed layer was exceeded, an enhanced contribution of P-losses resulted
through tile drains in clay loam soils.457 P-losses in tile-drain effluent were
increased where manure was applied, compared with unfertilized control
plots.458 Subsurface transport of P may occur as water-soluble-P and as
particulate-P in both undrained and tile-drained plots.459
451
Campbell and Racz, 1975; B. Eghball, G.D. Binford, and D.D. Baltensperger, 1996, “Phosphorus
movement and adsorption in a soil receiving long-term manure and fertilizer application,” Journal
of Environmental Quality, 25, p. 1339.
452
Eghball, Binford, and Baltensberger, 1996.
453
N.S. Bolan, R. Naidu, S. Mahimairaja, and S. Baskaran, 1994, “Influence of low-molecularweight organic acids on the solubilization of phosphates,” Biology and Fertility of Soils, 18, p. 311.
454
R.E. Stephenson and H.D. Chapman, 1931, “Phosphate penetration in field soils,” Journal of the
American Society of Agronomy, 23, p. 759.; J.S. Robinson, A.N. Sharpley, and S.J. Smith, 1995, “The
effect of animal manure applications on the forms of soil phosphorus,” Animal Waste and Land-water
Interface, K. Steele (ed.), (Boca Raton, FL: CRC Press), p. 43; Johnston and Poulton, 1997.
455
Campbell and Racz, 1975.
456
A.F. Harrison, 1987, Soil Organic Phosphorus: A Review of World Literature (Wallingford: CAB
International).
457
G. Heckrath, P.C. Brookes, P.R. Poulton, and K.W.T. Goulding, 1997, “Phosphorus losses in
drainage water from an arable silty clay loam,” Phosphorus Loss from Soil to Water, H. Tunney, O.T.
Carton, P.C. Brookes, and A.E. Johnston (eds.), (Wallingford, UK CAB International), p. 367.
458
G.W. Hergert, D.R. Bouldin, S.D. Klausner, and P.J. Zwerman, 1981, “Phosphorus concentrationwater flow interactions in tile effluent from manured land,” Journal of Environmental Quality, 10, p. 338.
459
R.M. Dils and A.L. Heathwaite, 1997, “Phosphorus fractionation in grassland hill-slope
hydrological pathways,” Phosphorus Loss from Soil to Water, H. Tunney, O.T. Carton, P.C. Brookes,
and A.E. Johnston (eds.), (Wallingford, UK: CAB International), p. 349.
The Management of Manure in Ontario with Respect to Water Quality
173
At a field scale, even when sorption capacities in the surface horizon are exceeded
and the water-soluble-P concentration become elevated, lower soil horizons may
be able to sorb the leaching-P and minimize the potential for water-soluble-P
movement to surface waters via drainage.460 Similarly, immobilization of P on
metal oxides (which can be present on the surface of particles within an aquifer)
can decrease as the P-loading of soil increases.461 However, preferential flow can
be an important factor in tile-drain losses of particulate-P.462 The importance of
preferential flow for P-transport was confirmed by the fact that P was leached
from the soil despite the large adsorption potential of some subsoils.463 Although
water-extractable-P was concentrated in the uppermost layer of the soil profiles
at the time of most peaks in flow, P-concentrations in tile-drain effluents strongly
increased with increasing flow rates.464 Phosphorus was mainly transported as
soluble-reactive and particulate-P through preferential flow paths extending from
the soil surface to the drains. On clayey soils in an intensively cropped area in
Quebec, up to 50% of the P lost through tile-drain effluent was in particulate
forms, with less than 30% in soluble forms.465
3.3.5.3 Metals
Transport of metals through a soil is mostly a function of its acidity and
concentration of dissolved oxygen. Accumulation of organic material close to
the surface may possibly decrease the availability of Zn while increasing the
solubility of iron and manganese.466 Other studies show that although
460
T.L. Provin, B.C. Joern, D.P. Franzmeier, and A.L. Sutton, 1995, “Phosphorus retention in
selected Indiana soils using short-term sorbtion isotherms and long-term aerobic incubations,”
Animal Waste and Land-water Interface, K. Steele (ed.), (Boca Raton, FL: CRC Press), p. 35.
461
D.A. Walter, B.A. Rea, K.G. Stollenwerk, and J. Savoie, 1996, Geochemical and Hydrologic
Controls of Phosphorus Transport in a Sewage-contaminated Sand and Gravel Aquifer near Ashumet
Pond, Cape Cod, Massachusetts (Washington, D.C.: United States Geological Survey), Water-supply
paper 2463.
462
Heckrath et al., 1997; J.D. Gaynor and W.I. Findley, 1995, “Soil phosphorus loss from conservation
and conventional tillage in corn production,” Journal of Environmental Quality, 24, p. 734.
463
Eghball, Binford, and Baltensperger, 1996; D. Thomas, G. Heckrath, and P.C. Brookes, 1997,
“Evidence of phosphorus movement from Broadbalk soils by preferential flow,” Phosphorus Loss
from Soil to Water, H. Tunney, O.T. Carton, P.C. Brookes, and A.E. Johnston (eds.), (Wallingford
UK: CAB International), p. 369.
464
C. Stamm, H. Fluhler, R. Gachter, J. Leuenberger, and H. Wunderli, 1998, “Preferential transport
of phosphorus in drained grassland soils,” Journal of Environmental Quality, 27, p. 515.
465
S. Beauchemin, R.R. Simard, and D. Cluis, 1998, “Forms and concentration of phosphorus in
drainage water of twenty-seven tile-drained soils,” Journal of Environmental Quality, 27, p. 721.
466
L.M. Shuman, 1988, “Effect of organic matter on the distribution of manganese, copper, iron,
and zinc in soil fractions,” Soil Science, 146, p. 192.
174
Walkerton Inquiry Commissioned Paper 6
the addition of organic material (in manure) to soil tends not to alter the total
dissolved Zn, the Zn changes from being linked with low-molecular-weight
organic particles to being associated with heavy organic particles. These heavy
particles tend to be adsorbed by the soil complexes.467 On the other hand, Cu
interacts with dissolved organic carbon of low molecular weight, which is more
likely to stay in solution and thereby increase the percentage of mobile Cu.468
Increases in the ionic concentration of the soil solution, as happens shortly after
manure application, may decrease the percentage of metallic ions attached to soil
mineral and organic particles by increasing the competition for adsorption sites.469
3.3.5.4 Bacteria
Bacterial transport is affected by soil pH. Long-term land application of cattle
or pig manure can result in a decrease in soil pH.470 This potentially reduces
bacterial transport due to an increase in the number of binding sites available
for bacterial adsorption. It may also affect bacterial survival. Cattle manure
induced smaller soil pH changes compared with pig manure.
The moisture content of the soil prior to rainfall is another important factor in
water movement and consequently contaminant transport. Abu-Ashour et al.
conducted a series of experiments to determine factors influencing bacterial
transport through soil.471 Their findings indicated that initial soil moisture was
the critical variable in determining the extent of bacterial migration. In dry soil,
none of the marked bacteria (biotracer) were detected below 87.5 mm. However,
the biotracer travelled the full length of the soil columns (175 mm) if the soil was
wet. If water was added after biotracer inoculation, the biotracer moved deeper
into the soil. The actual depth depended upon how close to saturation the soil
became after the addition of a given volume of water. The water may have increased
467
Del Castilho et al., 1993b.
N. König, P. Baccini, and B. Ulrich, 1986, “Der Einfluß der naturlichen organischen Substanzen
auf die Metallverteilung zwischen Boden und Bodenlösung in einem sauren Waldboden,” Zeitschrift
Für Pflanzenernärung und Bodenkunde, 149, p. 68; Del Castilho et al., 1993b.
469
F.J. Stevenson, 1991, “Organic matter-micronutrient reactions in soil,” Micronutrients in
Agriculture, 2nd ed., J.J. Mortvedt, F.R. Cox, L.M. Shuman, and R.M. Welch (eds.), (Madison,
WI: Soil Science Society of America), p. 145.
470
Chang, Sommerfeldt, and Entz, 1991; Bernal et al., 1992.
471
J. Abu-Ashour, C. Etches, D.M. Joy, H. Lee, C.M. Reaume, C.B. Shadford, H.R. Whiteley, and
S. Zelin, 1994a, Field Experiment on Bacterial Contamination from Liquid Manure Application,
Final Report for RAC Project No. 547G (Toronto: Ontario Ministry of Environment and Energy).
468
The Management of Manure in Ontario with Respect to Water Quality
175
the soil water content sufficiently to allow the bacteria to move through the soil
with percolating water. However, bacteria can be transported to depth even if the
soil is not saturated.472
A further factor influencing bacteria transport following liquid manure application
is the large concentration of salts present in manure. The salts may act as “bridges,”
allowing negatively charged bacteria to adsorb to negatively charged soil particles.
High salt concentrations can also decrease the thickness of the diffuse double
layers around soil colloids, thereby allowing bacteria access to surfaces to which
they can adhere. The addition of rainwater dilutes the salt concentration, thus
increasing the thickness of the double layer and possibly causing the flushing out
of adsorbed bacteria.473 This increases the number of bacteria that remain mobile
in the soil solution and increases the risk to groundwater.
Harvey has shown that the transport of bacteria may be faster, slower, or similar
to that of tracers, such as chloride or bromide, that are not transformed into
other compounds.474 Bacteria move through soils and aquifers by several
mechanisms, including continuous, discontinuous, and chemotactic
migration.475 Much of the modelling effort has treated transport as a continuous
process, which assumes passive transport of bacteria. However, bacterial
movement through the subsurface, especially over substantial distances, may
be discontinuous because of processes that temporarily remove bacteria from
solution. Bacteria are removed from the flowing water by straining or by
reversible sorption on solid surfaces. They are remobilized later. Discontinuous
transport creates an apparent retardation of the bacteria relative to conservative
tracers. Retardation factors as large as 10 have been reported for bacterial
populations travelling through porous aquifers.476
472
S.W. McMurry, M.S. Coyne, and E. Perfect, 1998, “Fecal coliform transport through intact soil
blocks amended with poultry manure,” Journal of Environmental Quality, 27, p. 86; A. Unc, 1999,
Transport of Faecal Bacteria from Manure through the Vadose Zone, M.Sc. thesis, University of Guelph,
Ontario.
473
Y. Tan, W.J. Bond, A.D. Rovira, P.G. Brisbane, and D.M. Griffin, 1991, “Movement through
soil of a biological control agent, Pseudomonas fluorescens,” Soil Biology & Biochemistry, 23, p. 821.
474
R.W. Harvey, 1991, “Parameters involved in modelling movement of bacteria in groundwater,”
Modelling the Environmental Fate of Microorganisms, C.J. Hurst (ed.), (Washington D.C.: American
Society for Microbiology), p. 89.
475
G. Bitton and R.W. Harvey, 1992, “Transport of pathogens through soil and aquifers,”
Environmental Microbiology, R. Mitchell (ed.), (Toronto, ON: Wiley-Liss Inc.), p. 103.
476
G. Matthess, A. Pekdeger, and J. Schroeter, 1988, “Persistence and transport of bacteria and
viruses in groundwater: A conceptual evaluation,” Journal of Contaminant Hydrology, 2, p. 171.
176
Walkerton Inquiry Commissioned Paper 6
Bacteria may also travel significantly faster than chloride or bromide due to motility.
Movement due to taxis (self-propulsion) is faster than that caused by random thermal
(Brownian) motion. Motile bacteria penetrated Berea sandstone cores in the presence
of a nutrient gradient up to eight times faster than non-motile ones.477
Bacteria may also appear to travel faster than conservative tracers for other
reasons. Bacterial transport is restricted to macropores, whereas conservative
tracers diffuse into the soil matrix as well as the larger pores. This may cause
the average peak in bacterial concentrations to appear earlier than that of the
conservative tracer. The bacteria are exploiting faster paths but can travel only
during peak flow, whereas the average tracer concentration, moving through
the soil matrix and macropores, would not peak until the majority had infiltrated
through the soil matrix.478 The impact of preferential flow on the velocity of
bacterial transport, relative to the average pore water velocity, is evident from
table 3-19. Near the soil surface, where the structure is more uniform because
of tillage, bacteria move at a rate similar to the average pore water. Deeper in
the soil profile, bacterial movement is much faster than the average pore water
because they are concentrated in the preferential flow paths.
In addition to transport processes, the kinetics of bacterial population growth
and decay must be considered in relation to the timing and numbers of
Table 3-19 Average Migration Velocity and Velocity Relative to Average
Pore Water for Bacteria from Contrasting Manures
Manure
Liquid swine
Solid beef
Depth (m)
0.3
0.75
1
Average bacterial migration velocity
(cm/d)
3
9.4
34.8
Migration velocity relative to
average pore water velocity
0.7
3.8
23.0
Average bacterial migration velocity
(cm/d)
3.4
6.3
11.9
Migration velocity relative to
average pore water velocity
Soil profile was loam over silt-loam.
Source: after Unc, 1999.
477
1.3
3.8
7.1
G.E. Jenneman, M.J. McInerney, and R.M. Knapp, 1985, “Microbial penetration through
nutrient-saturated Berea sandstone,” Applied Environmental Microbiology, 50, p. 383.
478
Bitton and Harvey, 1992.
The Management of Manure in Ontario with Respect to Water Quality
177
organisms reaching a water resource. Microorganisms adsorbed to soil particles
may survive longer than those in the liquid phase, as organic substrate and
nutrients are more readily available to them.479
The Ontario Farm Groundwater Quality Survey demonstrates the importance
of preferential flow for bacterial transport since bacteria were found in properly
maintained drilled wells greater than 30 m deep.480 Preferential flow can thus
facilitate the transport of contaminants to aquifers at depths that might be
expected to remain unaffected by surface contaminants. This presents an
important concern for predictions of bacterial transport. For example, when
flow parameters in the theoretical model described by Corapcioglu and Haridas
were taken to the permissible limits, the predicted extent of bacterial transport
through unsaturated soil over 2 weeks was 0.2 m.481 Tamási reported that E. coli
and Salmonella typhimurium, applied in liquid manure, rarely penetrate deeper
than 1.6 m in packed columns of either a sand or a garden soil.482 But Smith et
al. observed that E. coli penetrated through a column of undisturbed soil to a
depth of 0.3 m in 20 minutes.483 Harvey et al. observed that bacterial-sized
microspheres were transported through several metres of aquifer material.484
Unc estimated the depth of soil necessary to filter out bacteria from manure
applied under field conditions.485 Based on bacterial counts measured at 0.75
m, values ranged from 0.1 m to more than 20 m (figure 3-8), demonstrating
the importance of preferential flow paths. The vertical distribution of beneficial
microorganisms applied to the soil also depends on preferential flow.486
479
M.D. Sobsey, 1983, “Transport and fate of viruses in soils,” Microbial Health. Considerations of
Soil Disposal of Domestic Wastewaters, L.W. Canter, E.W. Akin, J.F. Kreissl, and J.F. McNabb (eds.),
(Cincinnati, OH: U.S. Environmental Protection Agency), p. 175.
480
Goss, Barry, and Rudolph, 1998.
481
M.Y. Corapcioglu and A. Haridas, 1985, “Microbial transport in soils and groundwater: A
numerical model,” Advances in Water Resource, 8, p. 188.
482
G. Tamási, 1981, “Factors influencing the survivial of pathogenic bacteria in soils,” Acta Veterinaria
Academiae Scientiarium Hungaricae, 29, p. 119.
483
Smith, Unwin, and Williams, 1985.
484
R.W. Harvey, L.H. George, R.L. Smith, and D.R. Leblanc, 1989, “Transport of microspheres
and indigenous bacteria through a sandy aquifer: Results of natural and forced-gradient tracer
experiments,” Environmental Science & Technology, 23, p. 51.
485
Unc, 1999.
486
A. Natsch, C. Keel, J. Troxler, M. Zala, N. Von Albertini, and G. Defago, 1996, “Importance of
preferential flow and soil management in vertical transport of a biocontrol strain of Pseudomonas
fluorescens in structured field soil,” Applied and Environmental Microbiology, 62, p. 33.
178
Walkerton Inquiry Commissioned Paper 6
3.3.5.5 Protozoa
The transport of protozoa has been studied in far less detail than bacterial
transport has. The movement of Cryptosporidium parvum oocysts through
saturated columns of glass spheres, coarse sand, or shale aggregate has been
modelled. The oocysts (from dairy calves) did not adhere to sand or glass spheres,
moving throughout the system of pores between the particles. The oocysts
moved preferentially in the larger pores between shale aggregates. Sand was
more effective at removing oocysts than were the other particles, probably by
filtration. The authors suggested that their results indicated that significant
transport was possible in both surface runoff and with infiltrating water.487
Figure 3-8 Variation in the Depth of Soil Required to Filter Bacteria
in Manure
Initial volumetric soil moisture
0.25
0.24
0.17
0.34
0
-2
Soil depth (m)
-4
-6
-8
-10
-12
-14
-16
Loam over silt loam
Loam over sandy loam
Soil type
Liquid swine manure
Solid beef manure
Liquid swine and solid beef manure were applied to loam over sandy-loam and loam over silt-loam soils. The drier
conditions on the loam/silt-loam soil when liquid manure was applied likely increased preferential flow because of
channel formation by shrinkage.
Source: Unc, 1999.
487
C.F. Brush, W.C. Ghiorse, I.J. Annguish, J.Y. Parlange, and H.G. Grimes, 1999, “Transport of
Cryptosporidium parvum oocysts through saturated columns,” Journal of Environmental Quality,
28, p. 809.
The Management of Manure in Ontario with Respect to Water Quality
179
3.3.5.6 Endocrine-disrupting compounds
If manure containing endocrine-disrupting compounds is left on the soil surface,
it can move to surface water in runoff (see section 3.2.8.4). The identification
of equol in tile-drainage water is evidence that these compounds can at least
leach from soil and move into surface water. Given that similar compounds are
not readily identified in the soil,488 it seems likely that the movement to the
tile drains is mediated by preferential flow. Therefore, it is also possible for
these compounds to move to groundwater via similar pathways.
3.3.5.7 Summary
Only a small part of the nitrogen from manure is likely to be lost in surface
runoff from arable fields. More P is likely to be lost in runoff than by leaching.
Leaching to groundwater is a significant pathway for NO–3 loss. Mobility of
metals in soil is likely to be increased when they are applied in animal manure.
Bacteria can impact surface water through runoff and in tile drainage. They
can also be transported to groundwater. The movement through soil of all
potential contaminants from manure is enhanced by preferential flow.
3.3.6 Predicting contamination of water resources by components
of manure
Many models have been developed to predict the NO–3 concentration in water
leaving the rooting zone of crops and the impact or risk of contamination from
agricultural practices.489 The NLEAP model predicts the risk of groundwater
contamination by nitrate for applications of manure.490 However, predictions
of nitrogen mineralization from manure and of gaseous losses lacks validation
for Ontario.
488
M. Colucci, H. Bork, and E. Topp, 2001, “Persistence of estrogenic hormones in agricultural
soils I:17beta-Estradiol and estrone,” Journal of Environmental Quality, [In Press].
489
M.J. Shaffer, A.D. Halvorson, and F.J. Pierce, 1991, “Nitrate leaching and economic analysis
package NLEAP model description and application,” Managing Nitrogen for Groundwater Quality
and Farm Profitability, R. Follett, D.R. Keeney, and R.M. Curse (eds.), (Madison WI: Soil Science
Society of America), p. 85; Ahuja, Barnes, and Rojas, 1993.
490
Shaffer, Halvorson, and Pierce, 1991.
180
Walkerton Inquiry Commissioned Paper 6
Although the presence of pathogenic bacteria in both manure and receiving
waters is well documented, and the phenomena influencing bacterial transport
are known, the actual effect of manure on the quality and quantity of bacterial
contamination is less well understood. Aspects of bacterial transport have been
studied, but mainly under laboratory conditions. Such experiments have mostly
evaluated the effects of various individual factors on the bacterial transport.
Thus, while many predictive models for the transport of soluble forms of
contaminants have been developed, few models exist that describe bacteria
transport. Those that are available are still in the formative phase (e.g., the
LEACHB routine of the LEACHM program491). No account is taken of the
potential effect of the manure on the bacterial transport, despite the fact that
manure is one of the major sources of pathogens contaminating groundwater
and surface waters. The possibility for preferential flow needs to be included in
such models. The microbial model in LEACHB considers microbial dynamics
as affected by substrate availability and prey-predator interaction. Bacterial
growth and distribution can influence the transport of solutes. The model,
however, does not refer to physical movement of bacteria. The only movement
between locations is considered in the context of the distribution of available
substrates. The model also does not allow for a bacterial population to die. All
these characteristics make the model suitable for describing the movement of
indigenous soil bacteria that are in a dynamic equilibrium, but not the transport
of fecal bacteria introduced in an application of manure.
3.3.6.1 Summary
While many models exist to describe nitrate leaching, the concentration of NO–3
(the important determining factor) is difficult to predict because of the factors
that influence the final concentration, such as mineralization of organic nitrogen
and the gaseous loss of ammonia and gases such as N2O. Bacterial transport in
the unsaturated zone is poorly described in existing models because they largely
ignore the component of movement associated with preferential flow.
491
J.L. Hutson and R.J. Wagenet, 1992, LEACHM – Leaching estimation and chemistry model,
Version 3. Research Series No. 92-3 (Ithaca, NY: Dept. of Soil, Crop and Atmospheric Sciences,
Cornell University).
The Management of Manure in Ontario with Respect to Water Quality
181
3.4 Future Research Needs
This review of manure management practices highlights the significant
knowledge gaps that limit our ability to prevent contaminants from manure
reaching water resources. Producers recognize the potential benefits of using
the crop nutrients in manure, both because it is a means of reducing costs and
it contributes toward the sustainable use of resources. Most of the guidance
from government and researchers is aimed at conserving nutrients during
manure storage and optimizing their availability to crops after field application.
It is assumed that this approach will minimize environmental contamination
from nitrogen (nitrate, nitrite, ammonia and other N-containing gases) and
phosphate. Little attention has been given to developing manure management
practices for field application that are specifically designed to deal with
pathogens. Nonetheless, there is a Best Management Practice (BMP) to identify
the minimum safe distance between a well and the point where manure is
spread to minimize contamination by pathogens, and another aimed at
preventing liquid manure from flowing directly into a tile drain (see section 2).
Environmental aspects of other potential contaminants identified in this section
have not been incorporated into recommended manure management practices.
Two reports have made recommendations on manure-related research.492 Both
concentrated on aspects of nutrient management. Researchers have made
significant progress toward meeting those recommendations, particularly those
that relate to water quality. Based on the limitations presented in this section,
however, some recommendations still require a significant research effort to
safeguard water resources from contamination by nitrate, phosphate, and organic
carbon compounds in manure.
The following research recommendations are related to the availability of crop
nutrients in manure and the protection of water resources.
•
492
Establish the relationship between environmentally safe and most profitable
rates of manure application to cropland, taking account of the method and
timing of applications. This also requires the development of more acceptable
manure application methods in conservation tillage systems.493
Miller et al., 1990; M.J. Goss, J.R. Ogilvie, E.G. Beauchamp, D.P. Stonehouse, M.H. Miller, and
K. Parris, 1994, Current State of the Art of Manure/Nutrient Management, COESA Report No. RES/
MAN-001/94 prepared for Research Branch, Agriculture and Agri-Food Canada.
493
Miller et al., 1990; Goss et al., 1994.
182
Walkerton Inquiry Commissioned Paper 6
•
Complete the means of predicting the composition of the major types of
manures, based on feeding regimes, and investigate the long-term effects
of feed additives on manure management. This should include studies
on the dynamics of carbon compounds from feed and the impacts of
different handling systems.494
•
Investigate and develop the ability to predict the transformations of
manure-N during storage (including composting) and following addition
to soil to characterize the mineralization, immobilization, and N-gas
forming processes that impact on the availability of N to crops and the
loss of ammonia and nitrous oxide.495
•
Leaching of nitrate from grazed pastures and fields receiving regular
applications of manure needs to be determined for Ontario conditions.496
Further research is also warranted on the amount of metals being applied to
Ontario fields, especially in swine manure. As the use of copper in feed is
related to perceived reductions in the use of antibiotics in animal husbandry,
research efforts need to be integrated in these areas.
Continued research on manure management in relation to pathogens is clearly
required. From the perspective of animal husbandry, clear knowledge gaps
surround the shedding of E. coli O157:H7, particularly about seasonality, the
influence of diet, and dietary changes. Information on the shedding of other
pathogens is also not well documented. Vaccines to prevent the colonization of
cattle by E. coli O157:H7 need to be developed.
The link between the different serotypes of several pathogens found in animals
and the incidence of disease in humans needs to be clarified.
Economically viable treatments of manure in storage, which can effectively
conserve nutrients and reduce the loading of pathogens, need to be developed.
These must be considered in conjunction with odour control.
494
Goss et al., 1994.
Miller et al., 1990; Goss et al., 1994.
496
Goss et al., 1994.
495
The Management of Manure in Ontario with Respect to Water Quality
183
In Ontario, few practising agricultural engineers work on machinery, particularly
that for land application of manure. However, improved application equipment
is needed to ensure that the appropriate rates of manure are applied to meet
crop requirements indicated by nutrient management planning, while protecting
water resources from contamination. There is a specific need for manure injectors
with more rapid throughput capacity.
Application techniques need to be developed to reduce the likelihood of
preferential flow when liquid manure is applied. This should be coupled with
the development and evaluation of predictive models for the transport to
groundwater of dissolved and particulate contaminants, such as bacteria and
other pathogens, that take hydrological factors into account.
The fate of organic compounds, such as antibiotics and natural estrogens, needs
to be determined quantitatively, including the possibilities of reducing the
content in manure during storage as well as considering transport to water
resources once manure has been applied to the land. Application techniques
that discourage preferential flow would probably reduce the likelihood of
groundwater contamination.
Few BMPs for manure management have been evaluated under commercial
farming. These activities need to be accelerated to ensure that the best advice is
available to producers.
3.4.1 Summary
There are significant needs for research in the field of manure management if
water resources are to be protected from contaminants originating in manure.
These needs cover aspects of feeding regimes, animal husbandry, manure
treatment, and field application. They include both basic and applied research
and machinery development. The contaminants to be considered include
nitrate, phosphorus, metals, pathogens, antibiotics, and natural endocrinedisrupting compounds.
184
4
Walkerton Inquiry Commissioned Paper 6
Manure Production in Ontario
4.1 Background
This section provides basic information on the distribution of livestock farms
in Ontario, the species of animals involved, and the amounts of manure
produced. It focuses on the likely changes in manure production over the next
5–10 years within the province. When looking at manure production in the
future, many factors have been taken into consideration, including:
•
•
•
•
market trends in both the domestic and export markets;
the possible impact of new manure-management technologies;
international trade agreements, e.g., the World Trade Organization which
has as its long-term goal tariff reductions and ensuring fair trading
practices; and
the level of competition from other provinces and the United States.
4.2 Objectives
The overall objective of this section is to benchmark manure production levels
within the province and to forecast growth for the major livestock industries in
Ontario by geographic region. The specific objectives are:
•
to describe Ontario’s livestock industries in terms of farm numbers,
amount of crop land, manure spreading practices, and economic scale.
•
using Statistics Canada census data, to catalogue historical and current
animal numbers at both a county/municipality and township level for
the species of beef, dairy, swine, turkey, chicken, and laying hens.
•
based on the animal numbers, to calculate historical and existing manure
production at both the county/municipality and township level.
•
using the manure production calculations, to determine the total amount
of nitrogen (N), phosphorus (P), and potassium (K) in livestock manure.
•
to develop livestock growth predictions for the major livestock industries
of beef, dairy, swine, turkey, chicken, and laying hens.
The Management of Manure in Ontario with Respect to Water Quality
•
185
using this information, to forecast the amount of manure likely to be
produced in the next 5–10 years.
4.3 Methodology
The livestock and poultry inventory numbers were obtained from Statistics
Canada’s census years of 1986, 1991, and 1996.497 Data were also obtained
from Statistics Canada to graph historical cattle and pig inventories. Breakdowns
by animal size for cattle and swine were obtained from Ontario Ministry of
Agriculture, Food and Rural Affairs (OMAFRA) statistics.498 The OMAFRA
numbers for swine were identical to the Statistics Canada numbers. Although
the beef numbers differed slightly for July 1999 between Statistics Canada and
OMAFRA, the OMAFRA numbers were used for determining inventory
percentages. This method provided a reasonable and recent allocation of animal
sizes for the purpose of calculating manure production. The OMAFRA data
were not used to generate animal number forecasts.
To calculate the number of animals per livestock unit, we used the guidelines set
by OMAFRA for calculating minimum distance separations.499 A livestock unit
is defined as the “equivalent value for various types of animals including poultry,
based on manure production and production cycles.”500 Minimum distance
separation calculations are used to determine the recommended distance between
a livestock operation and another land use, such as a neighbour.501 This distance
is influenced by the type and amount of livestock in the facility and the type of
manure handling system. The intent of minimum distance separations is to reduce
the number of complaints related to odour and land use.
Appendix 4-1 shows these calculations by livestock type. Census and MDS II
categories for calculating livestock units are not always the same. In these cases,
497
Canada, Statistics Canada, Agriculture Division, 1987, Census of Canada, 1986 – Agriculture –
Ontario (Ottawa: StatsCan); Canada, Statistics Canada, Agriculture Division, 1992a, Agricultural
Profile of Ontario, Part 1: 1991 Census (Ottawa: StatsCan); Canada, Statistics Canada, Agriculture
Division, 1997, Agricultural Profile of Ontario: 1996 Census (Ottawa: StatsCan).
498
Ontario, Ministry of Agriculture, Food and Rural Affairs, 1999b, Number of Cattle, Ontario [by
County], <www.gov.on.ca/OMAFRA/english/stats/livestock/index.html>; Ontario, Ministry of
Agriculture, Food and Rural Affairs, 1999c, Number of Pigs, Ontario [by County], <www.gov.on.ca/
OMAFRA/english/stats/livestock/index.html>.
499
OMAFRA, 1995b; OMAFRA, 1995c.
500
OMAFRA, 1995c.
501
Ibid.
186
Walkerton Inquiry Commissioned Paper 6
the census category was matched to the MDS II category that would result in
a maximum number of livestock units. For example, a census category called
“all other pigs” includes pigs from birth to market weight, excluding sows and
boars. MDS II categories include weaner pigs (20 pigs/LU) and feeder pigs
(4 pigs/LU). In order to estimate manure production at the upper end, it was
assumed that the category “all other pigs” are entirely feeder pigs, with 4 animals
per livestock unit. While this practice likely overstated the actual number of
livestock units for each livestock type, it is preferable to underestimating. This
approach was also used to calculate manure production, as it provides
information on the maximum amount of manure produced.
To predict livestock numbers and manure production in the future, we sought
input from various producer organizations. This information is summarized in
section 4.5 and the questionnaire used is found in appendix 4-2. Each commodity
group was asked the same questions, which focused on livestock growth predictions
and new manure-management technologies. Other methods used to predict future
animal numbers included baseline projections supplied by Agriculture and AgriFood Canada, input from industry analysts, and computer-generated linearregression trendlines based on historical livestock numbers.
There are several limitations to the manure projections presented here.
•
Manure estimates are based on the average daily volumes of fresh material
excreted by the various animal groupings reported by OMAFRA (see
appendix 4-3). No allowance has been made in the manure calculation
for water used in washing, frequently used in the swine and dairy
industries. Typically, stored swine manure is more than 95% water. As
well, no allowance has been made for straw, shavings, or other bedding
material which is used extensively by some livestock production systems
(e.g., dairy). While straw and shavings do not increase the concentration
of manure, they do increase the volume to be utilized.
•
The manure calculations fail to include manure generated from sheep,
horses, and nontraditional livestock such as deer, elk, bison, and llamas.
This exclusion may mean that the total amount of manure produced is
somewhat underestimated.
•
The volume of manure generated does not take rainwater into account.
Rainwater can add a significant volume if the manure is stored outside in
The Management of Manure in Ontario with Respect to Water Quality
187
an uncovered tank. Recall that Ontario receives about 750–900 mm of
rainfall annually (the 30-year average for Ridgetown College, University of
Guelph, for the eight-month period between April 1 and November 30 is
645.4 mm).
•
Many areas of the province have been amalgamated in recent years.
However, most of the census data at the township level used in this report
was collected before amalgamation and does not reflect recent municipal
restructuring.
•
Livestock numbers are not based on an average of beginning and ending
animal numbers, but rather the number of animals on hand at given
points in time (e.g., census or Statistics Canada inventory dates). This
assumes a consistent number of animals in the province and does not
allow for fluctuations in production. Manure production (litres/day/
animal) is based on these actual inventory levels on each date and is
multiplied by 365 days to provide an annual value.
•
The most recent census in 2001 has not been analyzed, so recent increases
or declines in animal numbers at the county/municipality and township
level are not known.
Occasionally, animal numbers in a provincially designated region may not equal
the total provided for that particular region. This is due to rounding errors in
the calculations and because some data were not included at the township (or
even county/municipality) level due to confidentiality concerns.
4.4 Results
4.4.1 Farm Structure
Table 4-1, which depicts Ontario farms by revenue class for 1997, shows three
main trends. Firstly, the dependence of the farm family on off-farm income is
largely related to farm revenue. In 1997 for example, farm income contributed
negatively to the total family income in the $10,000 to $24,999 farm revenue
class. In Canada as a whole, 68% of dairy farms depend entirely on farm income.
Exclusive dependence on farm income for other farm types are: hog: 51%,
poultry and egg: 49%, and beef cattle: 12%.
188
Walkerton Inquiry Commissioned Paper 6
The second trend seen is that the bulk of Ontario’s agricultural sales comes
from relatively few farms. Only about 20% of the farms were in the top two
revenue classes ($250,000 and up) but those farms produced some 67% of all
agricultural sales. Although important in terms of numbers, farms with revenues
below $50,000 (38.6% of all farms in 1997) generally contribute very little to
overall production (a total of 5.2%).
Thirdly, it appears that high-revenue farms require significant capital investment.
Farms in the top revenue class had average net worths of $1,812,608 while
those in the lowest class had net worths of $313,718. These high-revenue farms
are also investing for the future, with an average net investment of 5.4%, while
low-revenue farms invested only 1.5% of assets.
In summary, a relatively small number (20.2%) of farms produce the majority
(67.1%) of total Ontario agricultural sales. Operators of these high-revenue
farms are committed to commodity-based production and invest in the future
of their farming enterprises.
Table 4-1 Profile of Ontario Farms by Revenue Class, 1997
Gross
Revenue
Class
Average Average
Off-Farm
Net
Average
Number Operating Income
per
Income
of
Number
Farm*($)
($)
of Farms Operators
Farms
(%)
Production (%)
Net
InvestNet
ments
Worth
as %
per Farm
of Assets
($)
$10,000 to
$24,999
7,632
1.5
(344)
45,136
18.8
1.6
313,718
1.5
$25,000 to
$49,999
8,055
1.5
1,716
34,847
19.8
3.6
370,554
3.5
$50,000 to
$99,999
6,810
1.5
12,900
35,059
16.8
6.2
516,952
2.9
$100,000
to
$249,999
9,924
1.7
32,384
18,374
24.4
21.5
784,531
3.2
$250,000
to
$499,999
5,073
1.9
60,060
16,168
12.5
23.0
1,144,058
4.7
$500,000
and over
3,121
2.2
225,387
19,733
7.7
44.1
1,812,608
5.4
All Classes
40,616
1.7
35,174
29,296
1100.0
00
100.0
693,005
3.9
* Off-farm income was reported for the operator (and his family) responding to the survey.
Source: Canada, Statistics Canada, Agriculture, 1997.
The Management of Manure in Ontario with Respect to Water Quality
189
4.4.2 Livestock Farm Numbers
In 1996, Ontario had 28,885 livestock farms (dairy, beef, hog, poultry/egg,
and livestock combinations).502 The bulk (60%) of these farms are located in
the two regions of Western and Southern Ontario. Northern Ontario has the
fewest livestock farms (1,309, less than 5%). The average number of livestock
farms per county/municipality in the regions of Southern, Western, Central,
and Eastern Ontario was 726. Table 4-2 shows a regional breakdown of livestock
farms. For a breakdown by county/municipality, see appendix 4-4.
Map 4-1 shows livestock farm numbers by county/municipality, based on 1996
census data. The five counties with the most livestock farms are Bruce, Grey,
Huron, Perth, and Wellington. Those with the lowest number of livestock
farms are in the extreme southern part of the province (Essex, Kent, and Elgin),
the Golden Horseshoe, and more northerly regions such as Muskoka District.
We do not consider the Northern region because of the sparse livestock numbers.
4.4.3 Historical Livestock Numbers
Figure 4-1 shows the historical livestock numbers in Ontario between July 1,
1976 and July 1, 2000. Statistics Canada Livestock Inventories are taken either
quarterly or biannually. (No inventory numbers are available for poultry.) The
Table 4-2 Total Number of Livestock Farms by Region
Ontario Region
Total Number of Livestock Farms
Southern
5,329
Western
11,910
Central
4,761
Eastern
5,576
Northern
1,309
Total Ontario
Source: Canada, Statistics Canada, Agriculture, 1997.
502
Canada, Statistics Canada, Agriculture, 1997.
28,885
190
Walkerton Inquiry Commissioned Paper 6
Map 4-1
Total Number of Livestock Farms by County/Municipality,
1996
Livestock Farms
0–400
400–800
800–1,200
1,200–1,600
1,600–2,000
100
0
100 kilometres
Source: Canada, Statistics Canada, Agriculture, 1997.
Pig Inventory
Census Data - Pigs
Cattle Inventory
July 1/00
Nov 1/99
July 1/98
Mar 1/98
July 1/96
Mar 1/97
Nov 1/97
Nov 1/95
July 1/94
Census Data - Cattle
Mar 1/95
Nov 1/93
July 1/92
Mar 1/93
Nov 1/91
July 1/90
Mar 1/91
Nov 1/89
July 1/88
Mar 1/89
Poultry Census Data
Numbers are expressed in million head. Beef and dairy cattle are combined. Both Statistics Canada census and
inventory data are used.
Poultry (million head)
34
Nov 1/87
0
July 1/86
35
Mar 1/87
.5
Nov 1/85
36
July 1/84
1.0
Mar 1/85
37
Nov 1/83
1.5
July 1/82
38
Mar 1/83
2.0
Nov 1/81
39
July 1/80
2.5
Mar 1/81
40
Nov 1/79
3.0
July 1/78
41
Mar 1/79
3.5
Nov 1/77
42
July 1/76
4.0
Mar 1/77
Cattle, Pigs (million head)
Figure 4-1 Historical Inventory of Cattle, Pigs, and Poultry in Ontario
from July 1, 1976 to July 1, 2000
The Management of Manure in Ontario with Respect to Water Quality
191
alignment between the Livestock Inventory numbers and the five-year census
data for cattle and pigs lends credibility to the projected manure production
calculations as both sets of data are used in forecasting inventory levels for
cattle and pigs. The Inventory shows 62% beef cattle and 38% dairy cattle.
The cattle inventory has shown a downward trend over the past 24 years, from a
high of 3.1 million head in 1976 to 2 million in the year 2000. This 35% decline
plays an important role in the amount of manure produced annually in the
province. The 24-year trendline for pigs is relatively flat, with inventory fluctuating
between 3 and 3.5 million head. Poultry has shown some growth, with a low of
37 million in 1986 expanding to 41.5 million in 1996, a 12% increase.
Figure 4-2 provides a more recent snapshot of beef and dairy cattle numbers
from Statistics Canada, Livestock Division. Between July 1995 and July 1999,
the dairy inventory has remained relatively constant but beef numbers have
increased and decreased yearly, with total inventory numbers trending
downward. The dairy cattle inventory ranged between 911,000 (July 1996)
and 811,000 head (July 1999). The beef cattle inventory ranged between
1.4 million (July 1995) and 1.2 million head (January 1999). Probable reasons
Figure 4-2 Ontario Beef and Dairy Inventory Values
(million head)
2.5
2.0
1.5
1.0
0.5
Jul 95
Jan 96
Jul 96
Jan 97
Total Inventory
Jul 97
Jan 98
Total Dairy
Jul 98
Jan 99
Jul 99
Total Beef
Source: Canada, Statistics Canada, Livestock and Animal Products Section, 2000, Livestock Statistics, 1976–2000
(Ottawa: StatsCan).
192
Walkerton Inquiry Commissioned Paper 6
why Ontario’s beef numbers have declined include: strong competition from
Western Canada, natural fluctuations caused when farmers retire, and poor
profitability caused by rising costs of production. Between 1995 and 1999, the
average beef farm had about 60 head while the average dairy farm had close to
100 head.
4.4.4 Livestock Units and Manure Production per County/Municipality
Table 4-3 shows the ranking of the top ten counties/municipalities in terms of
manure production in 1996. These county/municipality rankings changed only
slightly in the three census years. Huron County was ranked first in 1986 and
second in 1996. Other areas changing ranking between 1986 and 1996 were:
Middlesex (moved from 5th to 6th), Waterloo (8th to 7th), Bruce (6th to 5th),
and Grey (7th to 8th).
Most counties in Ontario experienced a decline in manure production between
1986 and both 1991 and 1996. Increases did occur in Kent (10.3% in 1991,
Table 4-3 Livestock Units and Top-ten Counties/Municipalities in
Terms of Manure Production, 1996
% Change 1991
Versus
1986
% Change 1996
Versus
1986
Area
Total Livestock
Units: 1996
(000s)
Total Manure
(million L/yr,
1996)
Perth
206
2678
2.1
6.8
Huron
212
2655
–2.5
4.1
Wellington
164
2010
–3.2
–4.2
Oxford
142
1848
–10.8
–6.7
Bruce
146
1781
–9.1
–7.0
Middlesex
131
1596
–6.1
–15.9
Waterloo Region
118
1521
–1.0
–5.3
Grey
125
1399
–8.3
–10.1
Lambton
95
1204
–9.4
–9.0
Simcoe
86
1012
–17.5
–18.6
Source: Canada, Statistics Canada, Agriculture, 1997.
The Management of Manure in Ontario with Respect to Water Quality
193
35.4% in 1996); Perth (2.1% in 1991, 6.8% in 1996), Renfrew (1.8% in
1991, 6.6% in 1996), and Huron (4.1% in 1996). For the province as a whole,
manure production between 1986 and 1991 decreased by 5.9% and between
1986 and 1996 by 7.5%. Eight counties or municipalities showed manure
production decreases of over 20% between 1986 and 1996. Listed in order
from the largest decrease to smallest, they are: Halton, Muskoka District, York,
Haliburton, Essex, Dufferin, Prince Edward, and Niagara. The decreases in
manure production tended to be more dramatic for the 10-year period of 1986
to 1996 than for the five-year period of 1986 to 1991.
It can also be seen from table 4-3 that the Western and Southern regions of
Ontario have by far the most livestock units and hence the most manure
production. For a complete listing of animal numbers, livestock units, manure
production, and percent change in manure production for all 39 Ontario
counties/municipalities, please see appendix 4-5.
An interesting trend is the changes in the numbers of livestock units between the
three species: poultry, cattle, and swine. This, of course, affects the amounts of
manure produced. In Bruce County, for example, manure production from swine
and cattle has decreased (by 33% and 1% respectively) while poultry manure has
increased some 61% between 1986 and 1996. In Huron and Perth Counties,
cattle manure production has decreased while swine and poultry manure has
increased. The Niagara Region shows manure production declining in all three
species, with swine decreasing some 45% over the 10-year period. Wellington
County has seen its poultry and cattle manure production increase (by 23% and
1% respectively), while swine manure production decreased (14%).
Map 4-2 summarizes the total number of livestock units by county/municipality
in 1996. The map illustrates table 4-3, showing that Huron, Perth and
Wellington have the greatest number of livestock animal units. As one would
expect, few livestock units are shown in the County of Essex, the Golden
Horseshoe, parts of the Eastern region, and more northerly parts of southern
Ontario. Map 4-3 depicts total manure production by county/municipality
for 1996. Not surprisingly, the distribution of manure production is very similar
to the distribution of livestock units seen in Map 4-2.
Table 4-4 summarizes animal units and manure production at the township
level in six counties/municipalities: Niagara, Oxford, Wellington, Perth, Huron,
and Bruce. The counties/municipalities were selected because of their
194
Walkerton Inquiry Commissioned Paper 6
traditionally high livestock numbers. Only the two townships in each area
with the greatest manure production are reported here. At the township level,
the changes in manure production tend to be more dramatic. For example,
Grey Township in Huron County saw manure production increase by 12.1%
between 1986 and 1991, while the 10-year growth between 1986 and 1996
was a huge 75.3%.
Of these six counties/municipalities, the townships in the Niagara region showed
the largest reduction in manure production. It is worth noting that even within
counties such as Huron and Perth, not all townships experienced increases in
manure production (see appendix 4-6). For example, manure production in
Blanshard Township in Perth County decreased by 34% over the 10-year study
period. For a complete breakdown of manure production in the six counties/
municipalities at the township level, see appendix 4-6.
When looking at manure production by species type at the township level,
some caution must be exercised. It is possible to have rapid manure production
growth on a percentage basis but still have a relatively limited expansion in
livestock units. For example, Kincardine township’s poultry units grew from
33 in 1986 to 528 in 1996, small by comparison with other townships, thus
Map 4-2
Total Number of Livestock Units by County/Municipality, 1996
Total Livestock Units
500–40,000
40,000–80,000
80,000–120,000
120,000–160,000
160,000–200,000
200,000–240,000
100
0
100 kilometres
The Management of Manure in Ontario with Respect to Water Quality
195
manure production increased by close to 1,363%. Still these percent changes
can be used to see general trends. By and large, the swine, poultry, and cattle
livestock units in most townships in the Niagara region have declined while
townships in the heavy livestock counties of Huron and Perth have increased
their swine and poultry livestock units.
Maps 4-4, 4-5, 4-6, and 4-7 show 1996 livestock units and manure production
at the township level for Huron County and Niagara Region. These two areas
were selected because they represent two different geographic regions of the
province. No obvious trends can be seen about locations of the different species:
one township doesn’t have all the pigs while others have all the cattle. Perhaps
Table 4-4 Livestock Units and Manure Production by Township, 1996
Total Livestock
Units (000s)
Total Manure
(million L/yr)
Change 1991
vs 1986
Change 1996
vs 1986
25.1
244.9
-20%
-23%
6.9
79.8
-17%
-21%
Zorra
39.9
539.3
-5%
-3%
East Zorra-Tavistock
28.4
381.4
-9%
5%
Peel
42.3
545.6
-1%
<1%
Maryborough
26.3
309.3
-9%
1%
Elma
28.5
354.6
-9%
-5%
Ellice
25.7
341.4
13%
30%
Grey
30.1
402.7
12%
75%
Howick
24.2
315.4
2%
12%
Carrick
17.5
223.0
-6%
-8%
Elderslie
16.3
213.8
-12%
12%
Township
Niagara
West Lincoln
Wainfleet
Oxford
Wellington
Perth
Huron
Bruce
Source: Canada, Statistics Canada, Agriculture, 1997.
196
Walkerton Inquiry Commissioned Paper 6
Map 4-3
Total Manure Production by County/Municipality, 1996
Total
TotalManure
Manure (million
(million L/y)
L/yr)
5–200
200–400
400–600
500–800
800–1,000
1,000–2,000
2,000–3,000
100
Map 4-4
0
100 kilometres
Huron County: Livestock Units by Township, 1996
22,695 Poultry
90,340 Cattle
98,851 Swine
3 0 3 kilometres
Note: Township animal numbers may not equal the total provided for the county/municipality due to rounding
error and confidentiality concerns.
The Management of Manure in Ontario with Respect to Water Quality
Map 4-5
197
Huron County: Manure Production (000 L/yr) by Township,
1996
148,244 Poultry
1,126,736 Cattle
1,380,411 Swine
3 0 3 kilometres
Note: Township animal numbers may not equal the total provided for the county/municipality due to rounding
error and confidentiality concerns.
Map 4-6
Niagara Region: Livestock Units by Township, 1996
36,816 Poultry
16.406 Cattle
9,315 Swine
7
0
7
14 kilometres
Note: Township animal numbers may not equal total provided for the county/municipality due to rounding error
and confidentiality concerns.
198
Walkerton Inquiry Commissioned Paper 6
one exception to this statement is the low poultry numbers in the northern
townships in Huron County. Niagara Region livestock units and manure
production are lowest in townships along Lake Ontario (a fruit farming area)
and those surrounding the Welland Canal (a housing area).
Table 4-5 shows the amounts of nitrogen, phosphorus, and potassium excreted
in livestock manures at the county/municipality level. The data are calculated
from the information in appendix 4-5 and N, P, and K values in appendix 4-3.503
For the province as a whole, the amount of nitrogen excreted decreased by 5.6%
between 1986 and 1991 and 6.7% between 1986 and 1996. Phosphorus and
potassium levels also decreased over both the 5- and 10-year periods: 5.5% and
6.2% for phosphorus and 6.6% and 8.2% for potassium. The decreases in these
nutrient amounts are not surprising. As was mentioned previously, manure
production decreased by 7.5% between 1986 and 1996.
Table 4-5 shows that the quantities of nitrogen produced decreased in all
counties except for Perth and Huron. These results track well with the previous
tables which showed manure production levels decreasing in most counties/
municipalities. The county/municipality with the largest increase in nitrogen
Map 4-7
Niagara Region: Manure Production (000 L/yr) by
Township, 1996
231,568 Poultry
213,739 Cattle
129,429 Swine
7
503
OMAFRA, 1995c.
0
7
14 kilometres
The Management of Manure in Ontario with Respect to Water Quality
199
was Kent with 28.2% (over 10 years) (with a 35% increase in manure
production) while Halton had the largest decline at 40.3% (with a 42%
reduction in manure) (see appendices 4-5 and 4-7). Maps 4.8 and 4.9 display
nitrogen and phosphorus levels by county/municipality for 1996.
On a regional basis, nitrogen excretion in manure declined in both Southern
and Western regions 1986 and 1996 (6.8% and 4.0% respectively). These two
regions account for 70% of Ontario’s livestock units and hence, manure
production.
Table 4-6 shows the nitrogen, phosphorus, and potassium amounts excreted
annually in livestock manure in 1986 and 1996 for two townships in each of the
six counties/municipalities listed earlier. Of the 71 townships in these counties/
municipalities, 46 experienced a decrease in nitrogen excretion between 1986
and 1996 while 25 had an increase. Niagara Region had the most townships
showing a decrease (10 of 12 townships) while Perth County had the fewest
townships with a decrease (only 4 of 11). As one would expect, urban townships
showed significant nitrogen declines (e.g., St. Catharines, 98.5% and Guelph,
Table 4-5 Nitrogen, Phosphorus, and Potassium Levels Excreted in
Manure in 1986 and 1996 in the Top-ten Counties/
Municipalities (in million kg/yr)
Area
1986 N
1986 P
1986 K
1996 N
1996 P
1996 K
% Change
in N
million kg/yr
Perth
8.8
4.5
7.3
9.3
4.9
7.2
5%
Huron
9.4
4.8
7.9
9.8
5.0
7.8
5%
Wellington
7.9
4.0
6.9
7.8
3.9
6.8
–2%
Oxford
7.2
3.7
6.3
6.5
3.3
5.7
–9%
Bruce
7.4
3.6
8.1
7.0
3.4
7.8
–5%
Middlesex
7.0
3.7
5.9
5.8
3.1
4.7
–17%
Waterloo
5.9
3.1
4.9
5.7
2.9
4.8
–5%
Grey
6.0
2.9
6.4
5.6
2.8
6.1
–7%
Lambton
4.5
2.4
3.4
4.1
2.2
3.0
–9%
Simcoe
4.7
2.3
5.0
3.8
1.8
4.0
–21%
Source: Canada, Statistics Canada, Agriculture, 1997.
200
Map 4-8
Walkerton Inquiry Commissioned Paper 6
Total Nitrogen by County/Municipality, 1996
Total NN(thousand
kg./yr)
Total
(million kg/y)
0–1.5
1.5–3.0
3.0–4.5
4.5–6.0
6.0–7.5
7.5–9.0
9.0–10.5
100
Map 4-9
0
100 kilometres
Total Phosphorus by County/Municipality, 1996
Total PN(thousand
Total
(millionkg./yr)
kg/y)
0–1.0
1.0–2.0
2.0–3.0
3.0–4.0
4.0–5.0
5.0–6.0
100
0
100 kilometres
The Management of Manure in Ontario with Respect to Water Quality
201
50.9%), while townships in counties traditionally rich in livestock showed the
most growth (e.g., Grey in Huron County, 64%). Appendix 4-7 provides detailed
data of the amounts of nitrogen, phosphorus, and potassium excreted in manure
in all counties and municipalities across Ontario.
Map 4-10 shows the amount of tillable land by county/municipality for the
southern portion of Ontario, as reported in the 1996 census data. Tillable land
is defined as land in crops and tame or seeded pasture. Notice that Huron,
Lambton, Middlesex, and Kent Counties have greater amounts of tillable land.
Table 4-6 Nitrogen, Phosphorus, and Potassium Excreted in Manure in
1986 and 1996, at the Township Level (in thousand kg/yr)
Area
1986 N
1986 P
1986 K
1996 N
1996 P
1996 K % Change in N
thousand kg/yr
Niagara
West Lincoln
1599
868
1131
1402
732
954
-12%
Wainfleet
372
204
303
346
170
260
-7%
Zorra
1975
995
1904
1894
947
1642
-4%
East Zorra -Tavistock
1242
633
1095
1308
666
1063
5%
Maryborough
1227
601
1019
1374
702
1064
12%
Peel
1973
995
1583
1998
993
1733
1%
Ellice
849
436
667
1031
537
672
22%
Elma
1484
762
1236
1385
692
1181
-7%
Grey
791
401
720
1297
665
959
64%
Howick
997
498
955
1115
554
1038
12%
Carrick
888
432
951
820
396
903
-8%
Elderslie
738
353
847
833
397
974
13%
Oxford
Wellington
Perth
Huron
Bruce
Source: Canada, Statistics Canada, Agriculture, 1997.
202
Walkerton Inquiry Commissioned Paper 6
Table 4-7 summarizes the information presented in the preceding sections. It
highlights, in particular, the fact that the Southern and Western regions of
Ontario have the majority of the total provincial livestock units (71%) and
also two-thirds of the total Ontario tillable land (69%).
One way to put Ontario’s livestock industry into perspective is to compare livestock
densities (livestock numbers per tillable hectare, 1 hectare (ha) = 2.47 acres) with
Map 4-10 Total Tillable Land by County/Municipality, 1996
Tillable Land (acres)
2,000–100,000
100,000–200,000
200,000–300,000
300,000–400,000
400,000–500,000
500,000–600,000
600,000–700,000
Table 4-7 Livestock Farms and Manure Production by Region
Ontario Region
Number of
Livestock
Farms
Livestock Units
(000s)
Manure
Production
(billion L/yr)
% of Total
Livestock Units
Tillable Land
(million
hectares)
Southern
5,329
684
8.1
27%
1.39
Western
11,910
1,121
13.8
44%
1.28
Central
4,761
293
3.3
11%
0.47
Eastern
5,576
373
4.6
14%
0.57
Northern
1,309
95
1.1
4%
0.18
2,568
30.9
100%
3.89
Total Ontario
28,885
Source: Canada, Statistics Canada, Agriculture, 1997.
The Management of Manure in Ontario with Respect to Water Quality
203
other jurisdictions, e.g., Denmark. Denmark is viewed as a strong competitor in
the international pork market yet maintains a strong environmental conscience.
It has 2.7 million tillable hectares (about 69% that of Ontario) but has a swine
density five times larger than in Ontario, a beef density about the same, and a
poultry density about 70%. Overall, Ontario’s livestock densities in head per
tillable hectare are: swine – 0.7; cattle – 0.6; and poultry – 10.7. Denmark’s
livestock densities are: swine – 4.1; cattle – 0.8; and poultry – 7.2. In terms of
global pork production density, countries such as Taiwan, Holland, Belgium,
and Denmark are thought to be at the high end of the scale while most of North
America is at the low end. One exception is North Carolina, which has pig
densities 2–5 times those found in most other states and provinces.
Livestock densities were also compared between Ontario and the state of Indiana.
Pig and cattle densities are similar while Ontario has a higher poultry density.
Appendix 4-8 shows complete details of livestock densities in the different
counties/municipalities of Ontario, plus those of Denmark and Indiana.
4.4.5 Manure Application
Table 4-8 shows manure application on farmland as a percent of the total
tillable land in six counties/municipalities in Ontario. The relative amounts of
Table 4-8 Tillable Land and Amount of Land under Liquid Manure
and Solid Manure Applications (as % of tillable hectares) in
Six Counties/Municipalities in Ontario†
Area
Total Tillable
Land
(000 ha)
Area Given Liquid
Manure
(% tillable ha)
Area Given Solid
Manure
(% tillable ha)
Niagara
68
4.8%
15.8%
Oxford
152
11.6%
12.3%
Wellington
157
9.0%
20.5%
Perth
180
12.3%
16.9%
Huron
249
7.0%
12.9%
Bruce
182
3.5%
21.3%
† Manure applied to land comes from all animal species raised in Ontario, e.g., including horses and sheep, not
just those highlighted in this paper.
Source: Canada, Statistics Canada, Agriculture, 1997.
204
Walkerton Inquiry Commissioned Paper 6
liquid and solid manure applied per tillable hectare vary considerably across
the province. For example, in Bruce County, the amount of tillable land receiving
liquid manure (3.5%) is relatively small compared with Perth (12.3%). In
Bruce County, however, more tillable land had solid manure applied (21.3%).
These differences are probably due to differences in livestock unit composition:
Bruce County has more beef animals and fewer swine, and thus is more likely
to use solid manure. Appendix 4-8 shows data on the percent of tillable land
under each type of manure application in all counties/municipalities of Ontario.
Table 4-8 and appendix 4-8 highlight the fact that even in counties with large
livestock numbers (such as Perth), the amount of tillable land receiving manure
application is modest (e.g., 30% in Perth). In Ontario as a whole, only 18.9%
of the tillable land receives manure. One could assume that the number of
livestock in the province could increase tremendously before running out of
tillable land on which to apply the manure.
This calculation does not, however, consider the amount of manure received
on a per-hectare basis. In 1996, the total estimated volume was 30.8 billion
litres and there were 3.9 million tillable hectares in Ontario.504 Simple division
results in each hectare receiving 7900 litres. This amount is low considering
that many operators apply approximately 34,000 litres per hectare.505 Given
this information it appears that if manure could be evenly distributed on all
tillable land across the province, then manure production could increase
significantly. The major obstacle to overcome would be the logistics involved
with the transportation of the manure to that tillable land.
Map 4-11 shows the percentage of tillable land receiving liquid manure in
Ontario. Liquid manure is more problematic than solid manure since it is
more likely to travel into field drains and ditches. It is not known why the
Ottawa-Carleton/Prescott/Russell region has a large amount of land receiving
liquid manure. The most likely explanation is that the region has a relatively
small land base with a substantial number of dairy farms, a large number of
which use liquid manure systems.
504
505
Canada, Statistics Canada, Agriculture, 1997.
D. Young, [Personal communication].
The Management of Manure in Ontario with Respect to Water Quality
205
4.5 Livestock and Manure Projections
The information and data in this section come from the appropriate producer
organizations. See appendix 4-2.
4.5.1 Dairy Farmers of Ontario
4.5.1.1 Animal Numbers in Next 5–10 Years
The demand for milk has been increasing by about 1–2% per annum. This
increased demand has been met primarily with increased cow productivity,
i.e., the same number of cows producing more milk per cow. The amount of
milk sold per cow rose by 18.3% between 1988 and 1999.
The average producer attrition rate is about 3% annually (1989: 9,408 dairy
farms versus 1999: 6,806), thus the overall trend is toward fewer, larger dairy
farms. The amount of milk sold per farm increased by 49.7% between 1988
and 1999. The vast majority of Ontario’s milk production comes from family
farms.
Map 4-11 Percent of Tillable Land Receiving Liquid Manure, 1996
% Receiving Liquid Manure
0–2
2–4
4–6
6–8
8–10
10–15
206
Walkerton Inquiry Commissioned Paper 6
Production has shifted somewhat from Peel and the Central region to the Eastern
and Western regions. The reasons for this shift include a higher frequency of
producers in Peel and the Central region nearing retirement age; a large number
of job options available for young people living in central Ontario; and a recent
influx of immigrant dairy farmers moving into Huron, Oxford, and Perth
Counties.
It has been suggested that cow and heifer numbers will remain the same in the
foreseeable future. Currently, a strong export demand for breeding heifers will
keep the number of tie-stall barns at current levels because they allow farmers
to provide more individual attention to the animals.
4.5.1.2 Future Production Facilities
The average herd size is about 55 cows, and the majority of farms have 50–80
cows. Presently, a farm with 600 cows is considered to be a “large dairy farm”
whereas just a decade ago, 200 was viewed as large. Most rural communities
seem receptive to larger dairy barns.
Approximately 25–30% of dairy farms have milking parlours while the
remaining operations use tie-stalls. In the next 5–10 years, the number of
milking parlours may increase to 35–40% of operations.
4.5.1.3 Manure Production
It was estimated that about 50% of the manure produced on a dairy farm is
liquid while the remaining 50% is solid. The most commonly used bedding
materials are straw, shavings, and sand.
4.5.1.4 Technological Advances
Not much change was anticipated in terms of technological advances that may
impact on either the quantity or quality of dairy manure produced in Ontario.
Farmers may have to become more conscious of matching the nutrients applied
with crop uptake.
The Management of Manure in Ontario with Respect to Water Quality
207
4.5.1.5 Demand for Product
It was speculated that World Trade Organization (WTO) talks would have no
impact on the domestic market for milk over the next 5–10 years. However,
WTO talks can potentially have an impact on the export market, since this is
where the trade challenges occur because of Canada’s supply-management system.
This round of talks will likely attempt to better define the existing trade rules
and limits rather than focus on reducing tariffs. The domestic milk market
accounts for 97% of the milk produced while exports only account for 3%.
4.5.2 Ontario Pork Producers’ Marketing Board
4.5.2.1 Animal Numbers in Next 5–10 Years
It is expected that animal numbers may grow by 1–5% as Ontario processors try to
optimize kill numbers to match plant efficiencies. In the past 10 years or so, hog sales
have varied from a low of 3.77 million in 1996 to a high of 4.65 million in 1988.
The long-term trend in producer numbers has been toward consolidation, with
fewer, larger farms. Producer numbers have declined steadily over the past 20
years from 18,000 in 1978 to 5,500 in 1998. Between 1971 and 1998, producer
numbers declined by about 6% annually. Producer numbers in the hogmarketing class of greater than 501 hogs have increased by 2.2% per annum.
4.5.2.2 Future Production Facilities
It is anticipated that production facilities will continue to become more specialized,
with fewer small farrow-to-finish operations. The feeling expressed on manure
handling was that manure will be stored outside the barn to reduce odour concerns,
with a minimum storage requirement of 240 days (and possibly 365 days).
4.5.2.3 Manure Production
Presently, most swine farms use a liquid manure system and this is not expected
to change. However, more farms will likely use some system of manure
separation, e.g., mechanical, in the future.
208
Walkerton Inquiry Commissioned Paper 6
4.5.2.4 Technological Advances
There is currently a great deal of experimentation and research on manure
production, treatment, and application. Considerable progress has been made
regarding manure production (e.g., the Enviropig: pigs capable of maximizing
the uptake of phosphorus and other nutrients on their own)506 and phytase feeding
(which can reduce the amount of phosphorus in swine manure by 30–35% and
the amount of nitrogen by 5%).
Considerable interest is being expressed in anaerobic digestion (without air)
for manure treatment. This might be applicable to large farms. Aerobic
treatments include composting (industry analysts estimate that only 5% of
farms use this treatment technique), high-rise barns with pigs on a carbon base
(e.g., straw), and a floating aerator. Research may improve manure spreading
techniques in terms of site-specific variable rates, e.g., the use of global
positioning surveillance technology, manure injection, and manure placement.
4.5.2.5 Demand for Product
North American pork consumption patterns have been relatively stable over
the last decade. Ontario normally exports 30–40% of its domestic pig
production to the global market place. The United States represents the biggest
export market, taking over 50% of all Canadian exports. One Canadian
processor currently exports over 60% of its pork product out of Canada.
Recent investments in the U.S. pork industry increased the number of megafarms and consolidated packing plants there, improving their production
efficiency and making the United States a net exporter of pork. In the early
1990s, the United States was a net importer of pork (354,000 tonnes of net
imports in 1990) but in 1997/98, it became a net exporter. By 2006, U.S. net
pork exports are projected to increase to 622,000 tonnes annually.
The Asian pork market is expected to be very favourable to North American
exporters. Japanese imports are projected to rise by 15% in the next 5 years.
Also, South Korea’s net pork imports are projected to almost double by 2006,
to 200,000 tonnes per year.
506
I. Lang, 2000, “Taking the next step: The Enviropig has arrived,” Pig Pens: News from the Univ.
of Guelph/OMAFRA Swine Research Program, Vol. VI, no. 2 (Spring), <www.uoguelph.ca/Research/
spark/pigpens/>.
The Management of Manure in Ontario with Respect to Water Quality
209
4.5.3 Chicken Farmers of Ontario
4.5.3.1 Animal Numbers in Next 5–10 Years
The growth rate in chicken production is expected to be about 3–4% annually
for the next 5–10 years, based on current per-capita consumption levels. The
number of registered producers is relatively stable at about 1,100 (1998: 1,093,
1999: 1,150) because production growth is distributed equally to all producers
based on quota holdings. Of the producers, 72% own 10,001–40,000 units of
quota (1 quota unit = 2 kg of chicken). The average production size is 20,000–
30,000 quota units.
Production is expected to increase in the traditional, land-based areas of
southwestern Ontario (Drayton, Clinton, and London), with production
shifting from the Niagara region where it is becoming more difficult to raise
chickens due to high land values and strict zoning legislation. Production has
not shifted to the Eastern region because of higher production costs there (farther
from the feed mills, hatcheries, processing, etc.). Corporate ownership is not
an issue with virtually all quota units held by traditional family farms.
4.5.3.2 Future Production Facilities
Slight changes in production facilities might include more concrete in manure
storage, covered pads, and an aeration system to reduce the potential for fire.
4.5.3.3 Manure Production
Most chicken farms use a solid manure system; very few use a liquid system.
The manure is either applied to the soil as fertilizer or sold to mushroom farms.
In chicken barns using in-floor heating, the waste product is more like sand.
This means the manure volume is reduced, since very little straw or shavings
are needed.
The Ontario industry is part of a national Certified Quality Assurance (CQA)
program which emphasizes manure management. CQA enforcement is through
a producer-driven board which can revoke an individual’s chicken-production
licence.
210
Walkerton Inquiry Commissioned Paper 6
4.5.3.4 Technological Advances
Little research emphasis is being placed on manure production or handling
within the chicken industry.
4.5.3.5 Demand for Product
In Ontario, the demand for live chicken is currently 60 million kg every 8 weeks.
The supply-management system prevents the flow of U.S. chicken into the
province. If this changed, it could severely damage Ontario’s domestic production,
given the large size of U.S. chicken farms.
4.5.4 Ontario Egg Producers
4.5.4.1 Animal Numbers in Next 5–10 Years
Bird numbers are expected to remain constant with any demand increases met
by productivity gains. The table market consumes 80% of the total output
while the industrial market consumes 20%. The industrial market is anticipated
to grow about 1% per annum. At any one time, there are about 7 million hens
(greater than 19 weeks of age) and 8 million pullets (less than 19 weeks of age).
Some consolidation is occurring due to economies of scale and the natural retirement
of older farmers. The 1,200 producers in 1980 has declined to about 400. The
average size of operation is estimated at 17,000 hens, up from 10,000 hens 10 years
ago. Some egg farms now have more than 80,000 birds. The average flock size is
estimated to rise to 25,000 hens in five years, raised by some 300 producers.
4.5.4.2 Future Production Facilities
The industry expects little change over present facilities. The three building
choices for hens are:
•
high-rise: two storeys with chickens upstairs, manure drops into a pit 8–10
feet high below the birds, with storage up to 1 year. The manure dries
The Management of Manure in Ontario with Respect to Water Quality
211
down (moisture is 75% when produced). All the manure is moved out at
once at 50–70% moisture.
•
traditional (1/3 of hens): birds are in cages over shallow pits, which are
cleaned daily, weekly, or every 3–5 weeks with a scraper moving the liquid
manure.
•
3 or 4 tiers of birds: beneath each row of cages is a moving plastic belt
which moves manure to the end of the row. Frequently the manure is
then moved with a stable cleaner and into a spreader.
Some facilities are changing from the traditional to the tiered system since it
permits higher densities of birds and lowers the cost of manure storage.
4.5.4.3 Manure Production
The majority of layer farm operators also grow crops, thus in most situations
the manure is spread on crop land. However, some producers may sell the
manure.
4.5.4.4 Technological Advances
Little manure technology is currently being developed. Phytase feeding may
be used in the future but it is at least 5 or 10 years away. Most hen feed is
pelleted and phytase cannot handle the heat used in the pelleting process. The
development of an Enviro-chicken is being considered at the University of
Guelph, but that is also about 5–10 years away. Composting has been discussed
but there has been limited uptake of this technology.
4.5.4.5 Demand for Product
Demand is flat and hens are producing more eggs. Any real demand changes
will come from the industrial side of the market.
212
Walkerton Inquiry Commissioned Paper 6
4.5.5 Ontario Turkey Producers’ Marketing Board
4.5.5.1 Animal Numbers in Next 5–10 Years
The 165 turkey producers in Ontario have a quota distribution as follows: 16 own
greater than 907,000 kg (9.6% of producers) while 71 have 1,000 to 113,400 kg
(42.5% of producers). Currently, most production is in Perth, Wellington, and
Waterloo Counties. The Niagara area used to be the prime location for turkey
production but has declined due to rural-urban pressures. Most operations remain
family farms with only seven quota holders having corporate ownership outside of
family members. There has been no trend to consolidation (i.e., fewer, larger farms).
4.5.5.2 Future Production Facilities
Little change is anticipated from the current systems. Turkeys are raised in
long, single-floor buildings, usually larger than 24,000 square feet. Manure is
normally stored in the barn until application time (usually spring). However,
some fall application can occur depending on the tillage system used.
4.5.5.3 Manure Production
Turkey manure is not piled outside for long periods because of bio-security
risks (e.g., rats). Turkey manure can be used for growing grapes, mushrooms,
or other crops.
4.5.5.4 Technological Advances
Limited research is being done on turkey manure. One feed company is trying
a feed additive to reduce phosphorus in manure. Also, one producer is
composting manure on a trial basis.
4.5.5.5 Demand for Product
The demand for the product is likely to remain constant over the next 5–10
years. The major fear is the importation of U.S. product. In the United States,
The Management of Manure in Ontario with Respect to Water Quality
213
one corporate farming entity produces over 1 billion kg of turkey, while the
whole country of Canada produces only 131 million kg.
4.5.6 Ontario Cattleman’s Association
4.5.6.1 Animal Numbers in Next 5–10 Years
The removal in 1995 of the Western Grain Transportation Act (WGTA), which
subsidized the export of prairie grains, had a positive effect on the western
Canadian livestock industry. The maximum grain freight rates more than
doubled (from $14.72/tonne to $30.63/tonne), resulting in lower feed prices
in the Prairies. As a result, Ontario has experienced a declining feedlot industry,
because calves now stay out west for finishing. Ontario’s largest feedlots are
estimated to have 3,000–4,000 head and 1996 census data calculates the average
size to be only 140 head.
Cow-calf operations are mainly spread across the province on marginal land, i.e.,
the Eastern and Northern regions. However, growth is not expected in the next
five years in this component of the industry despite the recent high calf prices.
The average cow-calf operation in 1996 had 23 cows, with only 20 farms having
more than 270 cows. Predominantly, most operations sell the weaned calves but
some finish them out to market weight.
4.5.6.2 Future Production Facilities
A trend to larger farms is expected as a result of alliances. However, cattle
feeding and manure handling systems are not expected to change.
4.5.6.3 Manure Production
Beef production systems vary, depending on economic size. Large feedlots tend
to store feed in bunkers, use a mixer wagon or truck to mix/distribute feed,
and use liquid manure systems. It is estimated that currently about 30% of
cattle manure systems are liquid. Small- to medium-sized farms normally use a
solid manure system.
214
Walkerton Inquiry Commissioned Paper 6
4.5.6.4 Technological Advances
Limited change regarding manure technologies is anticipated. New corn hybrids
that reduce the excreted N, P, and K levels may be developed, but this is not
likely to have much impact on manure production in the medium term.
4.5.6.5 Demand for Product
Bilateral, regional, and international trade agreements have liberalized meat
markets in Mexico, Japan, and South Korea over the last twelve years. As a
result, meat exports to these countries have increased rapidly. Consumption
has risen slightly in Ontario. There has been movement toward shelf-ready
products rather than sending whole carcasses to retailers.
4.5.7 Conclusion
The various livestock organizations anticipate limited change or implementation
in manure technologies for the main livestock commodity groups. Perhaps the
commodity group most likely to use new technologies is swine.
Producer groups were asked about trade agreements, particularly the World
Trade Organization talks. These talks could lower tariffs and impact negatively
on the supply-management commodities by allowing foreign imports into
Canada. All supply-management groups felt confident that this was unlikely
to happen in the short to medium term.
Animal numbers for dairy, swine, turkeys, and eggs are anticipated to remain
stable with limited growth. Chicken numbers are expected to increase by 3–4%
per year. It is unclear what will happen to beef cattle inventory numbers, however
expansion seemed unlikely.
4.5.8 National Perspective
The following comments on the national livestock situation were prepared by
Agriculture and Agri-Food Canada in their international and domestic market
outlook.507
507
Canada, Agriculture and Agri-Food Canada, 2000, Medium Term Policy Baseline – International
and Domestic Markets (Ottawa: AA-FC), <www.agr.gc.ca/policy/epad/english/pubs/mtb/mtbspt00/
septindx.htm>.
The Management of Manure in Ontario with Respect to Water Quality
215
4.5.8.1 Beef
Following the North American cattle markets, Canadian prices of feeder cattle
will remain strong until 2003 and then begin to decline. After a peak in 1996,
Canadian cattle inventories declined steadily as prices declined. Inventories
are projected to increase beginning in 2001 and continuing until 2006, which
is anticipated to be the peak of the cycle. Almost 70% of the increase in beef
production between 2001 and 2006 is expected to be exported. By 2006,
Canadian cattle farm output is expected to be 60% higher than the level observed
in 1995, before the elimination of the Western Grain Transportation Act.
4.5.8.2 Swine
The peak prices for Canadian hogs are projected to occur in 2000 and 2004.
The cyclical bottom will occur in 2003. Growing environmental concerns and
an anticipated tight market for feed barley are projected to slow the expansion
of hog production in Western Canada. Hog marketings in Eastern Canada are
expected to remain more stable than those in Western Canada. Almost two
thirds of the increase in pork production between 2000 and 2006 will be
exported. Canadian hog farm output at the end of 2006 is anticipated to be
53% higher than the level observed in 1995.
4.5.8.3 Poultry and Egg
The demand for poultry meat in Canada is projected to remain strong. Annual
per-capita consumption of chicken in 2006 is projected to be 6.2 kg above the
1996–1999 average. However, per-capita turkey consumption is projected to
remain unchanged at 4.3 kg. Canadian egg production at the end of 2006 is
projected to be 12% higher than the 1996–1999 average. Growth is stimulated
by a strong demand for breaker eggs from the agri-food processing industry. In
1990, breaker eggs accounted for 20% of all eggs produced in Canada. By
1999, this share had grown to more than 26% and is projected to increase to
over 30% by 2006. The growth in table egg consumption is projected to be
modest over the next few years.
216
Walkerton Inquiry Commissioned Paper 6
4.5.8.4 Dairy
Canadian fluid milk production in 2000/2001 is projected to increase 1.6%
from 1999/2000 as rising low-fat milk sales offset the decline of standard milk
sales. This trend is projected to continue into the future.
Thus in conclusion, beef and swine inventories are expected to increase but
only in the West, chicken and eggs could experience modest growth, while
turkey will remain constant. Fluid milk production is expected to increase by
about 1.6% per annum.
4.5.9 Livestock Projections for Ontario by Industry Analysts
Industry analysts felt that hog prices will be in a downward slide for the next
2–3 years. This downtrend is caused by a gradual expansion of the U.S. breeding
herd and continued strides in productivity. Thus, Ontario pig numbers are
expected to remain stable. Long-term production could shift from Ontario to
Western Canada because of rising environment-related costs.
Beef cattle numbers in Ontario are expected to continue their downward trend.
This is driven by cheaper feed costs in Western Canada, greater environmental
costs in Ontario, and the move to case-ready product.
These general comments are consistent with the projections made by both
producer groups and Agriculture and Agri-Food Canada.
4.5.10
Industry Trendlines
Future livestock inventory levels were projected by drawing an industry linearregression trendline, using data from July 1, 1976 to July 1, 2000. The trendlines
for poultry and cattle have relatively good statistical significance, with R2 levels
of 1 and 0.867 respectively. The reason for the high predictability for poultry
(100%) is because anticipated annual growth was expected to be 1.01% per year.
However, the future predictability for hogs was not as accurate, with only 15.04%
of the variability in pig numbers explained by historical inventory levels. The
trendlines for cattle, poultry, and pigs are shown in figures 4-3, 4-4, and 4-5.
Refer to Appendix 4-9 for specific livestock forecasts. Recall the study limitations
discussed previously in the Methodology when interpreting these forecasts.
Poultry Census Data
Forecast for Poultry
Linear (Poultry Census Data)
July 1/10
July 1/09
July 1/08
July 1/07
July 1/06
July 1/05
July 1/04
July 1/03
July 1/02
July 1/01
July 1/00
July 1/99
Forecast for cattle
July 1/98
July 1/97
July 1/96
July 1/95
July 1/94
July 1/93
July 1/92
Cattle Inventory
July 1/91
July 1/90
July 1/89
July 1/88
July 1/87
July 1/86
July 1/85
July 1/84
July 1/83
July 1/82
July 1/81
July 1/80
July 1/79
July 1/78
July 1/77
July 1/76
million head
July 1/10
July 1/09
July 1/08
July 1/07
July 1/06
July 1/05
July 1/04
July 1/03
July 1/02
July 1/01
July 1/00
July 1/99
July 1/98
July 1/97
July 1/96
July 1/95
July 1/94
July 1/93
July 1/92
July 1/91
July 1/90
July 1/89
July 1/88
July 1/87
July 1/86
July 1/85
July 1/84
July 1/83
July 1/82
July 1/81
July 1/80
July 1/79
July 1/78
July 1/77
July 1/76
million head
The Management of Manure in Ontario with Respect to Water Quality
217
Figure 4-3 Cattle Inventory Trendline, 1976–2010
3.5
3.0
2.5
y = -3.5249x + 2972.6
R2 = 0.8671
2.0
1.5
1.0
.5
0
Linear (Cattle Inventory)
Figure 4-4 Poultry Inventory Trendline, 1976–2010
60
y = 40.617x + 3180-9
R=1
50
2
40
30
20
10
0
218
Walkerton Inquiry Commissioned Paper 6
4.5.10.1 Swine Projections
From table 4-9 it can be seen that pig numbers are expected to increase modestly
from 3.3 million head to 3.5 million head (5.2%) over the next 10 years. Thus,
manure production from pigs is anticipated to increase by approximately 600
million L over the forecasted time frame.
4.5.10.2 Cattle Projections
Forecasted cattle numbers are presented in table 4-10. Total cattle numbers are
expected to decrease by about 20% over the 10-year time frame, resulting in a
corresponding 20% decrease in manure production.
4.5.10.3 Poultry Projections
Table 4-11 displays projected poultry numbers and manure production. Poultry
numbers are forecasted to increase by 10% over the 10-year period, thus annual
manure production will increase from 1.97 billion litres to 2.17 billion litres.
Figure 4-5 Pig Inventory Trendline, 1976–2010
4.0
3.5
3.0
y = 1.602x + 2845.6
R2 = 0.1504
2.0
1.5
1.0
Pig Inventory
Forecast for pigs
Linear (Pig Inventory)
July 1/10
July 1/09
July 1/08
July 1/07
July 1/06
July 1/05
July 1/04
July 1/03
July 1/02
July 1/01
July 1/00
July 1/99
July 1/98
July 1/97
July 1/96
July 1/95
July 1/94
July 1/93
July 1/92
July 1/91
July 1/90
July 1/89
July 1/88
July 1/87
July 1/86
July 1/85
July 1/84
July 1/83
July 1/82
July 1/81
July 1/80
July 1/79
July 1/78
0
July 1/77
0.5
July 1/76
million head
2.5
The Management of Manure in Ontario with Respect to Water Quality
219
In summary, using the trendlines, total provincial manure production is
forecasted to decrease from 29.5 billion litres in 2001 to 27.1 billion in 2010,
mainly due to the decrease in cattle manure.
Table 4-9 Forecasted Livestock Units and Manure Production: Swine
Year
Total Head (000)
Livestock Units (000)
Manure (million L/yr)
2001
3,328
815
11,328
2002
3,347
820
11,394
2003
3,366
824
11,459
2004
3,385
829
11,525
2005
3,405
832
11,610
2010
3,501
856
11,938
Table 4-10 Forecasted Livestock Units and Manure Production: Cattle
Year
Total Head (000)
Livestock Units (000)
Manure (million L/yr)
2001
1,912
1,322
16,242
2002
1,869
1,303
15,883
2003
1,827
1,273
15,523
2004
1,785
1,244
15,164
2005
1,742
1,206
14,749
2010
1,531
1,060
12,958
Table 4-11 Forecasted Livestock Units and Manure Production: Poultry
Year
Total Head (000)
Livestock Units (000)
Manure (million L/yr)
2001
44,008
311
1,973
2002
44,494
314
1,994
2003
44,979
317
2,016
2004
45,465
321
2,038
2005
45,950
324
2,060
2010
48,378
341
2,168
220
4.5.11
Walkerton Inquiry Commissioned Paper 6
Ontario Manure Growth Rates
The following are the weighted growth rates for the average annual swine and
cattle herd size in Ontario (supplied by Agriculture and Agri-Food Canada).
The estimated coefficients for the next four years are 2000 – 0.97; 2001 –
0.96; 2002 – 0.98; 2003 – 1.01; and 2004 – 1.03. These rates were also applied
to poultry inventory numbers, since proportionately they generate smaller
amounts of manure.
When these coefficients were applied against the estimated 1999 Statistics
Canada inventory numbers, the manure production amounts found in table
4-12 were generated. These manure production amounts are compared to the
trendline projections completed in section 4.5.10. The Agriculture and AgriFood Canada projections decrease during 2001 and 2002 but increase in 2003
and 2004. This is driven primarily by the cattle cycle which is expected to peak
in 2004. Thus, the trendline for manure production decreases each year, based
on the continuing decline in cattle numbers (despite the higher prices forecast
for 2000 and 2001).
Graphically, the difference in short-run manure production estimates can be
seen in figure 4-6. The largest gap between the two estimates is in 2002 when
the difference is about 890 million L. For the remainder of the time, the
difference is about 200–300 million L.
In conclusion, using linear-regression trendline projections, the estimated total
volume of manure is expected to decrease from the 30.9 billion L produced in
1996 to a forecasted 27.1 billion L in 2010. Forecasts from Agriculture and
Agri-Food Canada to 2004 report similar results. These results project decreases
Table 4-12 A Comparison of Manure Production Forecasts
Year
Ag Canada
Inventory
(000 head)
Ag Canada Manure
Production
Forecast
(million L/yr)
Trendline
Inventory
(000 head)
Trendline Manure
Production
Forecast
(million L/yr)
2000
46,788
30,168
48,802
30,314
2001
44,916
28,961
49,248
29,543
2002
44,018
28,382
49,710
29,271
2003
44,458
28,666
50,173
28,999
2004
45,792
29,525
50,635
28,727
The Management of Manure in Ontario with Respect to Water Quality
221
from 30.2 billion L in 2000 to 29.5 billion in 2004 while the trendline analysis
projects a decrease from 30.3 in 2000 to 28.7 in 2004.
4.6 Summary
Unquestionably, there is increased concern from the general public about the
environmental impact of animal agriculture. Members of the agricultural
community not only have to be aware of their rights and responsibilities to the
environment but they should also be proactive in taking action to protect the
land and water they themselves rely on.
The primary objective of this section has been to benchmark Ontario’s current
manure production levels and to project future growth predictions for the major
livestock industries in Ontario. The main data source was Statistics Canada’s
census data and livestock inventory numbers for beef, dairy, swine, turkey,
chicken, and laying hens. Input was sought from the producer groups regarding
industry growth and future manure technologies. The livestock manure
projections were done by using either using a simple historic trendline or
Agriculture and Agri-Food Canada’s future livestock predictions.
Figure 4-6 Potential Future Manure Production
31,000
30,000
(million L/yr)
29,000
28,000
27,000
26,000
25,000
2000
2001
Ag Can Forecast
2002
2003
Forecast from Trendlines
2004
222
Walkerton Inquiry Commissioned Paper 6
Limitations to the manure projections include failing to include wash and rain
water, and excluding some of the nontraditional livestock species (e.g., deer)
from the manure calculations. Further, the manure calculations do not include
any carbon-based materials (e.g. straw, shavings, etc.) which would add to the
total volume of manure produced. To recognize these limitations, manure
production was frequently estimated on the high side for several livestock
categories.
The majority of livestock farms are in the Western and Southern regions of
Ontario (17,239 out of 28,885 total livestock farms). The bulk of Ontario’s
agricultural sales comes from relatively few farms. Only about 20.2% of farms
have gross revenues over $250,000; however, these farms produce some 67%
of all agricultural sales. These statistics are not known for Ontario livestock
farms specifically, but it can be assumed that the same general trend holds true.
Current inventory levels of cattle (dairy and beef ) are about 2 million head, pigs
3.3 million head, and poultry 41.5 million head. The general trend in cattle
numbers is downward (beef cattle down, dairy cattle constant), while swine
numbers have been stable to increasing and poultry numbers have been increasing.
Based on 1996 census data, the top five ranking counties in terms of manure
production are Perth, Huron, Wellington, Oxford, and Bruce. The province as
a whole actually saw its manure production decrease between 1986 and 1996,
from an estimated 33.3 billion L to 30.9 billion L (a decrease of 7.5% over the
10-year period). Poultry manure production increased by 13.8% between 1986
and 1996, while cattle and swine manure decreased by 8.3% and 9.3%
respectively. In Huron and Perth Counties, the two heaviest livestock counties,
manure production for swine and poultry has increased while cattle volumes
have decreased. Another county/municipality of interest is Wellington which
has seen its poultry and cattle manure production numbers increase (23.1%
and 1.3% respectively) while swine manure production decreased (13.9%).
When manure production was reviewed at the township level, the swings in
manure production were sometimes dramatic. (‘Townships’ were the historical
townships, not those formed by recent township mergers.) For example, Grey
Township in Huron County saw manure production between 1986 and 1991
increase by 12.1% while the 10-year growth was 75.3%. No obvious trends
appeared, such as certain townships experiencing all the swine growth while
others showed all the cattle growth.
The Management of Manure in Ontario with Respect to Water Quality
223
Given the 7.5% decline in manure production for the whole province between
1986 and 1996, it is not surprising that nitrogen, phosphorus, and potassium
levels decreased as well. In the 10 years between 1986 and 1996, nitrogen,
phosphorus, and potassium decreased by 6.7%, 6.2% and 8.2% respectively.
The two regions that account for the bulk of Ontario’s livestock production
(Southern and Western) had nitrogen production declines of 6.8% and 4.0%
respectively. In six selected counties/municipalities, 46 of the 71 townships
experienced a decrease in nitrogen production between 1986 and 1996, while
25 had an increase.
The relative amounts of liquid and solid manure application vary considerably
by county/municipality. The main reason for this variance is the different
livestock unit composition (areas with more beef and fewer swine have more
solid manure to spread). More land in Perth and Oxford Counties received
liquid manure (approximately 12%) while Bruce and Wellington had more
land receiving solid manure (about 20%). It is interesting to note that even in
a heavy livestock county such as Perth, only about 30% of the tillable land
receives manure (in either liquid or solid form; 12.3% and 16.9% respectively).
In the province as a whole, the amount of tillable land receiving either liquid
or solid manure is 18.9% (5.2% and 13.7% respectively).
The fact that only 19% of all tillable land in the province receives manure
suggests that from a nutrient management perspective, Ontario could increase
its livestock inventories substantially before running out of tillable land on
which to spread manure.
The general consensus of farm organizations anticipated little wide-spread farm
application of new manure technology in the near future, although many
innovations are currently under development. When asked about the potential
impact of World Trade Organization talks that could lower tariffs and allow
foreign imports into Canada, producer groups felt that this was unlikely in the
short to medium term. Consumer demand for livestock proteins is expected to
remain relatively unchanged, with some growth in chicken consumption.
Future livestock manure projections were estimated in two ways: by drawing a
linear-regression trendline through historical livestock numbers and by using
growth coefficients supplied by Agriculture and Agri-Food Canada. From the
trendline, future pig numbers will increase over the next 10 year. Hence the
manure production is anticipated to increase by some 600 million L over
224
Walkerton Inquiry Commissioned Paper 6
the same timeframe. The most significant projection is total cattle numbers,
which are expected to decrease by about 20% over the next 10 years. Thus,
manure volumes should fall by some 3.3 billion L in that time. The inventory
increases expected for poultry and the manure production are both expected
to increase by about 10% over the next 10 years. Total provincial manure
production is forecasted to decrease from 29.5 to 27.1 billion L in the 10 years
from 2001 to 2010.
These projections track reasonably well with Agriculture and Agri-Food Canada’s
projections to 2004. They differ by some 890 million L in 2002 but for the
remainder of the time the difference is about 200–300 million L.
In conclusion, contrary to common belief, results indicate that Ontario’s manure
production has actually decreased by 7.5% between 1986 and 1996 (down
7.5%, from 33.4 to 30.9 billion L). Based on 1996 manure estimates, cattle
produced 63%, swine 31%, and poultry 6% of Ontario’s livestock manure.
Based on assumptions of falling beef cattle numbers, stable dairy numbers,
and increasing swine and poultry numbers, manure production is projected to
drop to 27.1 billion L in 2010 (a decrease of 12% from 1996 levels).
The ranking of counties/municipalities in terms of manure production changed
little over the 1986–1996 time period. At the township level, livestock numbers
did change, some rather dramatically, but no obvious trends appeared in which
types of livestock changed. With respect to manure application at the provincial
level, it would seem that there is room for significantly more manure production
based on estimated manure levels and tillable acres. However, site-specific
nutrient-management planning should also be considered.
There is little doubt that Ontario livestock farms are consolidating into fewer,
larger farms. The real question becomes how to balance society’s need for safe,
high-quality potable water versus the needs of livestock farms to remain
competitive (low costs of production) and not unduly burdened with extensive
regulations. It would appear that Ontario’s landbase could support about four
times the amount of manure currently produced if all tillable acres were to
receive manure application. However, given current manure technologies and
manure economic values (nutrient value plus cost of transportation), the
movement of manure over large distances does not seem feasible.
The Management of Manure in Ontario with Respect to Water Quality
225
Appendix 4.1 Coefficients Used to Calculate Livestock
Units
The calculations for livestock units were performed using the census data allocations
of animals per livestock unit (LU) and the MDS II guidelines.508
Pigs
By using four livestock units for the category “all other pigs,” the most extreme
scenario was created. This assumes that this group of pigs consisted of only feeder
hogs and no weaner pigs. This heavier weighting in livestock units was used for
each year.
Cattle (including beef and dairy)
The census methodology also provides a biased scenario for it assumes that all
calves weigh more than 150 kg. Bulls have been assigned as 1 head/LU given that
no separate classification was provided in the MDS II guidelines.
Table A4.1.1 Coefficients Used to Calculate Livestock Units for Pigs
MDS II Guidelines
# animals/LU
Census Category
# animals/LU
Sows/boars
5
Sows
5
Weaners (4–30 kg)
20
Boars
5
Feeder hogs (30–120 kg)
4
All other pigs
4
Table A4.1.2 Coefficients Used to Calculate Livestock Units for Cattle
MDS II Guidelines
# animals/LU
Census Category
# animals/LU
Beef cow (including calf to
150 kg)
1
Bulls
1
Beef feeders
2
Beef/dairy cows
1
Dairy cow (including calf
to 150 kg)
1
Heifers (beef and dairy)
2
Dairy heifers
2
Steers
2
Calves
2
508
OMAFRA, 1995c: Canada, Statistics Canada, Agriculture Division, 1992b, Census Overview of
Canadian Agriculture: 1971-1991 (Ottawa: StatsCan); Canada, Statistics Canada, Livestock and
Animal Products, 2000.
226
Walkerton Inquiry Commissioned Paper 6
Poultry
Note that these allocations assume the category “Other poultry” is similar to large
meat turkeys in terms of livestock units. Turkeys have been assigned livestock
units assuming they are all greater than 10 kg in weight.
Table A4.1.3 Coefficients Used to Calculate Livestock Units for Poultry
MDS II Guidelines
# birds/LU
Census Category
Chicken, caged layers
125
Laying hens 19 wks+(laying hens,
pullets 19 wks+)*
125
Chicken, breeder layers
125
Broilers, roasters, Cornish (other
hens, pullets, other chickens)*
200
Chicken, broilers/roasters
200
Pullets, pullet chicks
500
Chicken, pullets (replacement layers)
500
Hatchery flock birds
125
Meat turkeys (>10 kg)
50
Turkeys
50
Meat turkeys (5–10 kg)
75
Other poultry
50
Turkey breeder layers
75
Meat turkeys (< 5 kg)
100
Turkey pullets (replacement
breeders)
500
* Listing in brackets is category used in 1986 and 1991 census.
# birds/LU
The Management of Manure in Ontario with Respect to Water Quality
227
Appendix 4.2 Questionnaire for Producer Organizations
1.
What will happen to animal numbers for your industry in the next 5 to
10 years? In what regions of Ontario is this expansion or contraction
likely to occur?
2.
What will the production facilities of the future look like with respect to
size, feed storage, and manure storage ?
3.
What is likely to happen to manure production from this industry?
4.
Are any advances in technology likely to affect manure production (e.g.,
feed, odour)?
5.
What is expected to happen to demand for your industry’s product (e.g.,
shrink, expand)?
6.
Do you have any industry descriptive stats we could use (e.g., number of
farms, number of animals, regional or county/municipality breakdown
of these animals)?
7.
Do you have any production trends we could use (e.g., graphs depicting
recent production trends, statistics on ownership (corporate vs family),
shifts in farm size, types of feeding systems used, types of manure storage
and spreading systems used, etc.)?
Producer Organizations
The following producer organizations were contacted to gain a better understanding
of current and future production trends as well as potential technological events that
could affect production. The names of the individual(s) who participated are included.
Producer Organization
Dairy Farmers of Ontario
Ontario Pork Producers’ Marketing Board
Chicken Farmers of Ontario
Ontario Egg Producers
Ontario Turkey Producers’ Marketing Board
Ontario Cattleman’s Association
Name of Contact
Gordon Coukell
Sam Bradshaw
Chris Vanderkooy, John Maaskant
Dr. Peter Hutton
Greg Morrison
Mike McMorris
228
Walkerton Inquiry Commissioned Paper 6
Appendix 4.3 Calculation of Manure, Nitrogen,
Phosphorus, and Potassium Production
Values for annual manure production, plus annual nitrogen, phosphorus and
potassium content, were calculated.509 These calculations are used in later projections.
Pigs
Swine manure production and N, P, and K content were calculated using the
following data categories for pig type. There is no separate category for boars in
the Best Management Practices,510 so we assumed that all boars fall into the same
category as sows. To create a scenario that estimates the largest amount of manure
production, the category “all other pigs” assumes that all of these pigs are in the
largest weight range and therefore produce the maximum amount of manure.This
category was also allocated the N, P, and K production of 75% of a feeder hog
since the sow category in the census data includes the litter to weaning.
Cattle
Manure production and N, P, and K content were calculated using the following
categories for animal type, based on census data.511 There is no separate category
for bulls in the Best Management Practices,512 so we assumed that all bulls fall
into the beef cow category, which is higher in manure per animal than the beef
feeder category.
Beef and dairy cows produce different amounts of manure. The calculations for
total manure production were based on the number of each in the census data.
Heifers and steers were assigned the value corresponding to beef feeder/dairy heifer
Table A4.3.1 Calculation of Manure, Nitrogen, Phosphorus, and
Potassium Production for Pigs
Manure Produced
per Animal (L/day)
N (kg)
P (kg of P2O5)
Sows
11.3
16
9
5.5
Boars
11.3
11
6
4.5
All other pigs
9.1
4.5
3.4
Census Category
509
8.25
K (kg of K2O)
Canada, AA-FC, OMAFRA, and OFA, 1996; Canada, Statistics Canada, Agriculture, 1987,
1992a, 1992b, 1997.
510
Ontario, Ministry of Agriculture, Food, and Rural Affairs [n.d.], “Manure Characteristics,”
OMAFRA Factsheet, Agdex 528, order #85-109.
511
Ibid.
512
Ibid.
The Management of Manure in Ontario with Respect to Water Quality
229
(15–24 mos) to provide an upper limit of manure produced by this group of
animals. It was assumed that all calves fall into the 3–6 month age category (upper
range for calves). The N, P, and K production values for the category “Calves”
were assumed to be 50% of those of a beef feeder.
Poultry
Manure production and N, P, and K content were calculated using the following
categories for poultry type, based on census data.513 Turkeys and “other poultry” are
assumed to be the same as turkey breeders to give an extreme, upper-limit scenario.
Table A4.3.2 Calculation of Manure, Nitrogen, Phosphorus, and
Potassium Production for Cattle
Manure
Produced per
Animal (L/day)
N (kg)
P (kg of P2O5)
K (kg of K2O)
Bulls
28.3
32
15
40
Beef cows
28.3
32
15
40
Dairy cows
45.3
64
30
80
Heifers (beef and dairy)
21.2
32
15
40
Steers
21.2
32
15
40
Calves
7.1
16
7.5
20
Census Category
Table A4.3.3 Calculation of Manure, Nitrogen, Phosphorus, and
Potassium Production for Poultry
Volume
of manure
per bird
N (kg)
P (kg of P2O5)
K (kg of K2O)
Laying hens 19 wks+ (laying
hens, pullets 19 wks+)*
0.14
0.53
0.42
0.23
Broilers, roasters, Cornish
(other hens, pullets, other
chickens)*
0.08
0.35
0.16
0.14
Pullets, pullet chicks
0.08
0.35
0.16
0.14
Hatchery flock birds
0.14
0.53
0.42
0.23
Turkeys
0.34
0.53
0.42
0.23
Other poultry
0.34
0.53
0.42
0.23
Census Category
* Listing in brackets is category used in Canada.
Sources: Statistics Canada, Agriculture, 1987, 1992a, 1992b.
513
Ibid.
230
Walkerton Inquiry Commissioned Paper 6
Appendix 4.4 Number of Livestock Farms per County/
Municipality, 1996
Table A4.4.1 Dairy, Beef, Hog, Poultry/Egg, and Livestock
Combination Farms
Number of
Livestock
Farms
County/Municipality
Number of
Livestock
Farms
Hamilton-Wentworth Reg. Mun.
373
Prince Edward County
255
Niagara Regional Municipality
551
Northumberland County
656
Haldimand-Norfolk Reg. Mun.
630
Peterborough County
766
Brant County
241
Victoria County
977
Oxford County
1,232
County/Municipality
Durham Regional Municipality
932
Elgin County
349
York Regional Municipality
314
Kent County
269
Muskoka District Municipality
61
Essex County
106
Haliburton County
24
Lambton County
585
Parry Sound District
139
Middlesex County
Southern Ontario Region
Peel Regional Municipality
Dufferin County
Wellington County
Halton Regional Municipality
993
5,329
Central Ontario Region
4,761
Stormont,DDundas
undas &&GGlengarry
lengarry UU.C.
.C.
Stormont,
1,165
262
Prescott & Russell U.C.
729
463
Ottawa-Carleton Reg. Mun.
642
Leeds & Grenville U.C.
759
Lanark County
526
1,634
188
Waterloo Regional Municipality
1,132
Frontenac County
423
Perth County
1,744
Lennox and Addington County
392
Huron County
1,696
Renfrew County
940
Bruce County
1,711
Eastern Ontario
5,576
Grey County
1,919
Northern Ontario
1,309
1,161
Total Ontario
28,885
Simcoe County
Western Ontario Region
11,910
Hastings County
637
Source: Canada, Statistics Canada, Agriculture, 1997.
Average Number of Farms per
County/municipality Excluding
Northern Ontario
726
39
Swine
27
69
Cattle
Swine
47
90
Cattle
Swine
24
37
Cattle
Swine
86.4
1,766.4
119.5
194.2
14.9
328.7
243.6
371.0
109.7
24.2
169.1
229.9
250.0
649.0
100.7
10%
–11%
–4%
–8%
16%
–6%
–21%
–12%
42%
–10%
–28%
–12%
3%
–12%
–24%
–11%
1,898
28
20
366
414
63
41
2,558
2,662
38
22
5,877
5,937
22
21
2,650
2,692
71.9
984.5
97
66.5
268
99
13.7
136.6
8.6
15.0
2.4
26.0
17.4
29.1
17.9
64.4
12.1
17.2
40.8
70.0
7.2
61.9
161.6
–13%
–9%
1,440
1,768
35
22
407
464
71
40
2,320
2,432
50
23
5,768
5,841
29
13.0
10.2
324.1
Livestock
Head (000)
–10%
118.8
1,979.9
124.3
211.8
12.9
349.1
309.0
422.1
77.1
808.2
234.6
261.8
242.3
738.7
132.7
18
1,861
30.4
Manure
Production
(million
L/yr)
893.2
108
18.8
153.4
8.9
15.9
2.1
27.0
22.1
32.1
12.4
66.6
16.8
19.4
39.1
75.3
9.5
56.4
181.9
1,909
Livestock
Units
(000s)
1991
Swine
257
62.7
876.6
231
56.4
786.8
Note: The percent change in amount of manure between 1986 and 1991, and between 1986 and 1996 are also shown.
Cattle
9.3
14.3
371.0
Manure
Production
(million
Livestock
L/yr)
Head (000)
1,531
1,744
Poultry
2,109
337
Poultry
397
1,837
Poultry
1,974
5,565
Poultry
5,661
21
33.1
Livestock
Units
(000s)
1986
–27%
Oxford County
Brant County
Haldimand–Norfolk Regional
Municipality
Niagara Regional Municipality
1,600
Cattle
1,659
Livestock
Head (000)
Poultry
Hamilton-Wentworth
Hamilton–Municipal HRegional
amiltonMunicipality
Wentworth Regional Municipality
County/Municipality
Manure
chg. vs
1986
65.5
67.7
8.9
142.2
6.8
13.9
1.5
22.1
15.6
29.6
16.8
61.9
9.3
16.4
36.8
62.5
5.3
14.0
18.9
38.2
Livestock
Units
(000s)
1996
912.1
882.1
53.6
1,847.8
94.5
175.8
8.7
279.0
214.9
362.3
104.3
681.6
129.4
213.7
231.5
574.7
73.5
158.6
114.9
347.0
Manure
Production
(million
L/yr)
4%
–10%
–55%
–7%
–24%
–17%
–33%
–20%
–30%
–14%
35%
–16%
–45%
–18%
–4%
–22%
–45%
–13%
100%
–7%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, in 1986,
1991, and 1996
The Management of Manure in Ontario with Respect to Water Quality
231
Appendix 4.5 Livestock Head, Livestock Units, and
Manure Production by County/
Municipality in 1986, 1991, and 1996
Southern Ontario Region
Middlesex County
Lambton County
Essex County
Kent County
Elgin County
County/Municipality
35
83
Cattle
Swine
24
114
Cattle
Swine
38
Swine
106
261
Cattle
Swine
15,781
456
1,218
Poultry
Cattle
Swine
17,455
2,142
Poultry
2,509
36.0
58
231
Cattle
Swine
297.5
297.5
118.3
713.3
63.7
66.5
16.6
146.7
56.5
10.5
103.0
9.2
5.0
2.2
16.3
27.8
13.4
3.1
44.2
20.3
23.1
3.8
47.2
1,229
Poultry
7
Cattle
1,518
267
Poultry
312
450
Poultry
588
578
Poultry
696
Livestock
Head (000)
Livestock
Units
(000s)
1986
4,157.7
3,983.0
750.6
8,891.3
893.4
894.9
110.0
1,898.4
786.4
466.7
69.7
1,322.8
128.2
69.5
14.1
211.8
387.7
176.4
20.8
584.9
284.9
313.1
25.1
623.1
1,135
403
17,065
18,603
266
86
2,254
2,606
204
55
1,230
1,490
34
6
346
386
138
20
548
706
76
36
799
911
Manure
Production
(million
Livestock
L/yr)
HHead
ead ((000)
000s)
277.3
271.9
132.6
681.8
65.0
56.4
22.5
143.8
50.1
34.4
10.6
95.1
8.3
3.9
3.8
16.0
33.7
11.8
3.8
49.3
18.5
24.6
5.6
48.6
Livestock
Units
(000s)
1991
3,870.2
3,538.6
833.2
8,242.0
909.8
729.7
143.5
1,783.0
695.5
431.5
70.9
1,197.9
116.5
52.8
24.1
193.5
469.9
149.1
26.3
645.3
258.8
325.6
36.9
621.3
Manure
Production
(million
L/yr)
–7%
–11%
11%
–7%
2%
–19%
30%
–6%
–12%
–8%
2%
–9%
–9%
–24%
71%
–9%
21%
–16%
27%
10%
–9%
4%
47%
<–1%
Manure
chg. vs
1986
1,137
394
18,520
20,051
226
86
1,983
2,295
218
49
1,259
1,526
27
6
392
425
188
17
613
819
59
33
613
70 4
Livestock
Head (000)
278.1
266.4
139.8
684.2
55.3
56.8
19.1
131.2
53.3
31.4
10.6
95.3
6.7
4 .0
2.1
12.9
46.0
10.0
4.0
60.0
14.3
22.6
4.6
41.5
Livestock
Units
(000s)
1996
3,872.8
3,350.9
881.1
8,104.8
768.9
705.6
121.4
1,595.9
741.9
392.1
70.0
1,204.1
93.2
51.1
13.2
157.5
643.2
120.9
27.8
791.9
201.2
288.6
29.0
518.7
Manure
Production
(million
L/yr)
–7%
–16%
17%
–9%
–14%
–21%
10%
–16%
–6%
–16%
<–1%
–9%
–27%
–27%
–6%
–26%
66%
–31%
34%
35%
–29%
–8%
16%
–17%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
232
Walkerton Inquiry Commissioned Paper 6
Perth County
Waterloo Regional Municipality
Halton Regional Municipality
Wellington County
Dufferin County
Peel Regional Municipality
County/Municipality
30
Swine
12
Swine
81.1
95.0
122
388
Cattle
Swine
188.9
12.8
2,500
1,990
Poultry
52.5
85
230
Cattle
Swine
56.4
15.5
124.4
3.0
11.3
5.4
19.6
2,150
Poultry
17
Cattle
2,466
831
Poultry
860
82.3
125
268
Cattle
Swine
65.3
16.9
164.6
7.4
29.9
0.7
38.0
2,920
Poultry
45
Cattle
3,313
111
Poultry
187
8
1.8
18.2
26
Cattle
Swine
20.3
0.3
101
67
Poultry
Livestock
Head (000)
Livestock
Units
(000s)
1986
1,322.8
1,101.8
82.8
2,507.4
784.8
719.4
101.7
1,605.9
41.4
146.2
32.1
219.7
914.6
1,079.9
104.7
2,099.1
104.3
367.6
4.2
476.1
25.5
238.6
1.7
265.9
417
117
2,191
2,725
227
89
1,945
2,260
14
17
698
729
245
128
2,581
2,955
22
38
163
223
8
24
192
224
Manure
Production
(million
Livestock
L/yr)
Head (000)
102.2
79.3
13.9
195.4
55.4
54.0
12.8
122.1
3.4
10.9
3.5
17.8
59.9
85.9
16.4
162.3
5.4
26.2
1.0
32.5
2.0
16.9
1.2
20.0
Livestock
Units
(000s)
1991
1,419.3
1,051.8
89.7
2,560.9
774.2
734.7
81.0
1,589.9
47.6
144.3
21.7
213.6
835.2
1,096.5
100.5
2,032.3
75.7
306.1
5.8
387.6
27.0
220.7
7.0
254.6
Manure
Production
(million
L/yr)
7%
–5%
8%
2%
–1%
2%
–20%
–1%
15%
–1%
–33%
–3%
–9%
2%
–4%
–3%
–27%
–17%
39%
–19%
6%
–8%
310%
–4%
Manure
chg. vs
1986
46 0
112
2,592
3,165
207
89
1,921
2,216
3
13
401
417
230
131
3,290
3,651
13
39
225
277
5
24
93
122
Livestock
Head (000)
112.7
76.6
17.0
206.3
50.4
55.2
12.3
117.9
0.7
8.6
1.8
11.1
56.1
87.6
20.6
164.3
3.1
26.6
1.0
30.8
1.1
16.7
0.6
18.5
Livestock
Units
(000s)
1996
1,568.9
1,001.0
107.7
2,677.6
705.6
737.8
77.6
1,521.0
9.2
108.8
10.5
128.6
787.5
1,093.8
128.8
2,010.1
44.0
305.4
6.1
355.5
15.5
213.9
3.8
s233.2
Manure
Production
(million
L/yr)
19%
–9%
30%
7%
–10%
3%
–24%
–5%
–78%
–26%
–67%
–42%
–14%
1%
23%
–4%
–58%
–17%
47%
–25%
–39%
–10%
120%
–12%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
233
Hastings County
Western Ontario Region
Simcoe County
Grey County
Bruce County
Huron County
County/Municipality
98
Swine
84
1,016
1,596
Cattle
Swine
230
51
11
Poultry
Cattle
Swine
292
13,806
Poultry
16,419
74.6
112
Cattle
Swine
2.6
36.9
1.5
41.0
390.0
651.9
88.6
1,130.5
20.6
6.8
102.0
24.0
98.2
6.1
128.3
894
1,090
150
Cattle
Poultry
981
Poultry
1,229
113
27.6
114.4
189
Cattle
Swine
145.2
3.3
929
627
Poultry
88.8
89.4
145
364
Cattle
Swine
196.0
17.8
3,571
3,062
Poultry
Livestock
Head (000)
Livestock
Units
(000s)
1986
36.1
452.6
9.7
498.4
5,446.3
8,446.6
568.6
14,461.4
287.1
914.0
42.6
1,243.7
336.6
1,179.3
41.0
1,556.9
387.4
1,505.4
21.5
1,914.2
1,241.6
1,194.5
115.9
2,552.0
7
49
212
268
1,544
959
14,303
16,806
66
94
706
866
79
141
1,261
1,481
94
178
832
1,104
372
133
3,564
4,068
Manure
Production
Livestock
(million
L/yr)
Head (000)
1.7
35.6
1.3
38.6
377.6
628.3
90.6
1,096.6
16.3
64.0
4.8
85.0
19.4
95.3
7.8
122.4
22.9
111.6
4.5
139.0
90.9
84.2
21.8
196.9
Livestock
Units
(000s)
1991
23.9
431.8
8.1
463.8
5,263.7
7,901.1
574.0
13,738.9
225.4
770.8
29.6
1,025.8
270.5
1,106.8
50.5
1,427.8
321.6
1,390.5
27.9
1,740.0
1,267.2
1,078.8
141.0
2,487.0
Manure
Production
(million
L/yr)
–34%
–5%
–17%
–7%
–3%
–7%
1%
–5%
–22%
–16%
–31%
–18%
–20%
–6%
23%
–8%
–17%
–8%
30%
–9%
2%
–10%
22%
–3%
Manure
chg. vs
1986
6
49
167
220
1,511
987
15,718
18,216
64
95
675
834
49
149
1,346
1,545
76
193
1,032
1,300
4 05
14
4,057
4,604
Livestock
Head (000)
1.4
34.2
0.7
36.3
369.1
651.8
99.7
1,120.6
15.6
66.9
3.8
86.3
12.0
101.2
11.9
125.0
18.5
122.0
5.2
145.7
98.9
90.3
22.7
211.9
Livestock
Units
(000s)
1996
19.9
408.0
4.4
432.3
5,155.4
8,002.9
635.0
13,793.3
217.0
772.9
22.5
1,012.4
168.5
1,154.6
76.2
1,399.3
258.6
1,487.9
34.6
1,781.1
1,380.4
1,126.7
148.2
ssss2,655.4
Manure
Production
(million
L/yr)
–45%
–10%
–55%
–13%
–5%
–5%
12%
–5%
–24%
–15%
–47%
–19%
–50%
–2%
8 6%
–10%
–33%
–1%
61%
–7%
11%
–6%
28%
4%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
234
Walkerton Inquiry Commissioned Paper 6
York Regional Municipality
Durham Regional Municipality
Victoria County
Peterborough County
Northumberland County
Prince Edward County
County/Municipality
22
6
Cattle
Swine
50
27
Cattle
Swine
52
22
Cattle
Swine
70
33
Cattle
Swine
56
Swine
19.4
28
23
Cattle
Swine
5.7
1.8
27.0
13.8
49.9
6.4
70.1
7.2
47.5
0.7
55.4
5.4
37.4
2.9
45.7
6.5
35.6
3.9
46.0
1.4
15.6
1.3
18.3
591
Poultry
73
Cattle
643
1,150
Poultry
1,279
132
Poultry
235
549
Poultry
623
774
Poultry
851
354
Poultry
382
Livestock
Head (000)
Livestock
Units
(000s)
1986
79.8
248.3
10.9
338.9
191.9
628.7
39.4
860.0
95.8
551.7
4.6
652.2
75.5
432.4
17.7
525.5
91.2
440.5
27.6
559.2
19.9
207.4
7.5
234.8
16
21
792
829
34
68
1,326
1,428
21
64
166
251
16
52
556
624
23
48
790
861
3
19
412
433
Manure
Production
Livestock
(million
L/yr)
Head (000)
4.0
14.8
4.5
23.3
8.3
47.5
8.6
64.4
5.2
44.8
0.9
50.9
3.9
37.4
2.9
44.2
5.6
34.1
4.6
44.4
0.7
13.9
2.2
16.8
Livestock
Units
(000s)
1991
55.7
181.3
26.8
263.8
115.9
584.9
52.4
753.2
72.7
490.3
5.6
568.6
54.7
430.7
17.4
502.9
78.9
420.1
30.9
530.0
9.6
180.9
13.3
203.9
Manure
Production
(million
L/yr)
–30%
–27%
150%
–22%
–40%
–7%
33%
–12%
–24%
–11%
21%
–13%
–28%
<–1%
–2%
–4%
–13%
–5%
12%
–5%
–54%
–13%
75%
–13%
Manure
chg. vs
1986
11
21
727
75 9
37
65
1,205
1,308
15
67
126
209
11
50
588
649
26
45
543
613
2
18
239
25 8
Livestock
Head (000)
2.7
14.8
4.5
22.0
9.1
46.6
7.3
63.0
3 .7
47.9
0.8
52.4
2.6
36.2
4.2
43.0
6.4
32.4
3 .8
42.6
0. 4
13.3
1.4
15.1
Livestock
Units
(000s)
1996
37.5
180.4
27.1
245.0
125.1
563.3
45.3
733.6
51.8
526.3
4.9
583.1
36.2
4 0 8 .9
25.9
471.0
88.8
389.8
24.8
503.4
5.5
167.6
8.4
181.5
Manure
Production
(million
L/yr)
–53%
–27%
150%
–28%
–35%
–10%
15%
–15%
–46%
–5%
6%
–11%
–52%
–5%
47%
–10%
–3%
–16%
–10%
–10%
–73%
–19%
11%
–23%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
235
3
0
Cattle
Swine
1
0
Cattle
Swine
9
2
Cattle
Swine
361
180
Cattle
Swine
568
104
29
Poultry
Cattle
Swine
700
4,327
Poultry
4,867
28
Poultry
39
1
Poultry
3
5
8
Livestock
Head (000)
Poultry
Stormont, Dundas and Glengarry
United Counties
Central Ontario Region
Parry Sound District
Haliburton County
Muskoka District Municipality
County/Municipality
6.9
77.0
2.9
86.8
43.9
252.1
30.6
326.5
0.4
6.7
0.2
7.4
0.01
1.0
0.01
1.0
0.04
2.0
0.04
2.1
Livestock
Units
(000s)
1986
98.4
1,067.0
21.2
1,186.6
612.7
3,066.6
193.9
3,873.2
6.2
72.9
1.4
80.4
0.1
9.6
0.1
9.7
513.4
22.6
235.1
23.3
30
101
626
757
123
332
4,496
4,950
2
9
26
37
0
2
1
2
0
3
3
5
Manure
Production
Livestock
(million
L/yr)
Head (000)
7.4
74.8
3.5
85.7
30.0
237.7
29.0
296.8
0.4
6.5
0.2
7.1
0.02
1.2
0.01
1.2
0.1
1.9
0.02
2.0
Livestock
Units
(000s)
1991
103.9
1,031.7
24.2
1,159.9
419.4
2,821.6
179.9
3,420.9
5.9
69.8
1.3
77.0
0.3
11.9
0.05
12.1
1.5
7.7
116.6
9.3
Manure
Production
(million
L/yr)
6%
–3%
14%
–2%
–32%
–8%
–7%
–12%
–4%
–4%
–4%
–4%
360%
23.5%
–23%
25.4%
185%
–66%
–50%
–60%
Manure
chg. vs
1986
19
99
523
641
109
323
4,014
4,447
2
7
36
44
0
1
1
2
1
2
4
6
Livestock
Head (000)
4.6
73.8
3.0
81.5
26.8
233.1
32.6
292.5
0.4
5.5
0.3
6.1
0
0.7
0.01
0.7
0
1.5
0.03
1.6
Livestock
Units
(000s)
1996
64.5
1,001.1
19.2
1,084.8
372.1
2,725.2
202.8
3,300.2
5.3
58.1
1.7
65.1
0
7.0
0.05
7.0
0
15.9
0.2
16.1
Manure
Production
(million
L/yr)
–34%
–6%
–9%
–9%
–39%
–11%
5%
–15%
–14%
–20%
25%
–19%
–100%
–27%
–29%
–28%
–100%
–29%
–31%
–31%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
236
Walkerton Inquiry Commissioned Paper 6
12
Renfrew County
Lennox and Addington County
Frontenac County
24.6
0.3
26.9
34
1
399
Cattle
Swine
51.4
74
8
Cattle
Swine
2.0
0.2
53.6
37
118
16
Poultry
23.0
32
Cattle
Swine
3.8
0.03
351
Poultry
0.2
25.1
23
58
13
Poultry
43.6
61
Cattle
Swine
3.2
0.08
46.9
3.0
687
Poultry
761
48.7
68
Cattle
Swine
Leeds and Grenville United Counties
0.9
131
Poultry
6.6
52.6
27
211
54.0
Swine
71
Cattle
3.2
63.7
Livestock
Units
(000s)
1986
Ottawa–Carleton Regional Municipality
498
596
Livestock
Head (000)
Poultry
Prescott and Russell United Counties
County/Municipality
27.9
581.6
1.6
611.1
54.0
280.8
0.2
335.0
5.0
300.7
1.1
306.8
45.3
560.8
0.5
606.6
42.1
638.4
6.2
686.7
92.4
760.8
21.8
875.1
6
76
43
125
16
31
459
507
2
31
22
54
27
57
820
904
11
65
99
175
17
70
783
870
Manure
Production
Livestock
(million
L/yr)
Head (000)
1.6
54.4
0.04
56.0
4.0
22.4
3.0
29.4
1.1
28.6
0.05
29.8
6.6
42.4
0.1
49.1
2.8
47.5
0.7
50.9
4.1
53.1
4.6
61.8
Livestock
Units
(000s)
1991
21.9
600.3
0.2
622.4
55.6
268.2
21.5
345.4
15.6
330.1
0.3
346.0
91.7
533.7
0.9
626.3
38.5
610.6
4.2
653.3
57.9
747.5
32.2
837.5
Manure
Production
(million
L/yr)
–22%
3%
–86%
2%
3%
–5%
1,200%
3%
210%
10%
–73%
13%
100%
–5%
83%
3%
–9%
–4%
–33%
–5%
–37%
–2%
48%
–4%
Manure
chg. vs
1986
5
79
28
112
12
30
433
476
1
32
21
54
7
56
868
931
10
58
136
205
11
65
691
768
Livestock
Head (000)
1.3
57.6
0.02
58.9
3.0
22.3
2.7
28.0
0.3
27.6
0.1
28.0
1.8
41.2
0.02
42.9
2.4
43.3
0.5
46.2
2.8
49.7
4.1
56.5
Livestock
Units
(000s)
1996
18.3
632.8
0.1
651.3
42.3
263.6
18.9
324.9
3.5
312.5
0.7
316.7
24.6
502.8
0.1
527.5
33.5
552.7
3.3
589.5
38.8
685.2
27.4
751.5
Manure
Production
(million
L/yr)
–35%
9%
–91%
7%
–22%
–6%
1,000%
–3%
–31%
4%
–32%
3%
–46%
–10%
–77%
–13%
–20%
–13%
–47%
–14%
–58%
–10%
26%
–14%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
237
112
Swine
13
36,686
2,442
3,119
Poultry
Cattle
Swine
42,246
90.9
125
Cattle
Swine
761.8
1,643.3
254.6
2,659.7
3.2
2.4
96.5
27.2
350.9
14.3
392.4
348
487
483
Cattle
Poultry
2,364
Poultry
2,959
Livestock
Head (000)
Livestock
Units
(000s)
1986
10,645.5
21,092.9
1,634.8
33,373.2
45.0
1,069.6
16.2
1,130.8
383.9
4,527.1
102.4
5,013.4
2,925
2,286
39,113
44,324
9
123
270
402
114
46 9
2,878
3,461
Manure
Production
Livestock
(million
L/yr)
Head (000)
715.1
1,573.2
272.1
2,560.3
2.2
89.5
2.0
93.8
27.9
345.7
17.0
390.7
Livestock
Units
(000s)
1991
9,974.9
19,691.7
1,726.8
31,393.4
31.3
1,030.8
13.4
1,075.5
390.3
4,399.7
121.1
4,911.1
Manure
Production
(million
L/yr)
–6%
–7%
6%
–6%
–32%
–4%
–18%
–5%
2%
–3%
18%
–2%
Source: Derived and calculated from census data (Canada, Statistics Canada, Agriculture, 1987, 1992a, 1992b,1997).
Total Ontario
Northern Ontario Region
Eastern Ontario Region
County/Municipality
Manure
chg. vs
1986
2,831
2,286
41,519
46,636
8
124
288
420
67
45 8
2,767
3,291
Livestock
Head (000)
692.2
1,582.3
293.0
2,567.5
1.9
91.2
2.1
95.1
16.3
339.9
17.2
373.4
Livestock
Units
(000s)
1996
9,654.0
19,349.5
1,861.0
30,864.6
26.0
1,033.5
13.9
1,073.4
227.7
4,237.0
117.4
4,582.1
Manure
Production
(million
L/yr)
–9%
–8%
14%
–8%
–42%
–3%
–14%
–5%
–41%
–6%
15%
–9%
Manure
chg. vs
1986
Table A4.5.1 Livestock Head, Livestock Units, and Manure Production by County/Municipality, cont’d.
238
Walkerton Inquiry Commissioned Paper 6
19.4
16.8
Cattle
Swine
0.8
0
Cattle
Swine
0.8
0.3
Cattle
Swine
3.2
3.6
Cattle
Swine
17.3
10.3
5.2
Poultry
Cattle
Swine
32.7
0.9
Poultry
7.7
1.3
Poultry
2.3
0
Poultry
0.8
39.1
75.3
Poultry
Note: Blank areas represent no data available.
West Lincoln
Wainfleet
Port Colborne
Fort Erie
Niagara Regional Municipality
AREA NAME
Livestock
Units (000)
71.8
139.7
107.3
318.8
50.0
44.5
5.7
100.3
3.6
9.8
7.4
20.8
0
11.1
<0.1
11.1
234.6
261.8
242.3
738.7
Manure
(million L/yr)
1986
3.6
8.3
14.7
26.6
2.7
2.7
1.5
6.9
<0.1
0.7
1.3
2.1
0.5
0.9
<0.1
1.4
12.1
17.2
40.8
70.0
Livestock
Units (000)
1996
50.1
114.5
90.3
254.9
37.8
36.0
9.8
83.6
0.5
9.1
7.7
17.3
6.7
11.2
<0.1
18.0
169.1
229.9
250.0
649.0
–30%
–18%
–16%
–20%
–25%
–19%
71%
–17%
–85%
–7%
4%
–17%
1%
1,800%
62%
–28%
–12%
3%
–12%
3 .5
8.5
13.1
25.1
2 .4
2 .6
1.8
6.9
0
0.9
0.7
1.6
<0.1
0.5
0.7
1.2
9 .3
16.4
36.8
62.5
48.7
114.2
82.0
244.9
33.0
35.9
10.9
79.8
0
9.4
4.2
13.6
0.7
7.2
3.9
11.7
129.4
213.7
231.5
574.7
–32%
–18%
–24%
–23%
–34%
–19%
90%
–21%
–100%
–4%
–43%
–35%
–36%
131,000%
5%
–45%
–18%
–4%
–22%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their
Respective Townships, 1986, 1991, 1996
The Management of Manure in Ontario with Respect to Water Quality
239
Appendix 4.6 Total Livestock Units and Manure
Produced in Six Counties/Municipalities
and Their Respective Townships, 1986,
1991, 1996
AREA NAME
25.0
–22%
1.2
<0.1
0.3
1.0
<0.1
0.2
Swine
1.6
Cattle
Swine
0.1
0.2
2.1
Poultry
Cattle
Swine
2.5
1.1
0.8
Poultry
3.5
0.4
0.7
Cattle
2.4
29.6
0.8
0.7
31.1
22.3
3.3
6.6
32.3
3.0
9.1
0.6
1.8
0.4
2.0
4.2
0
0.6
1.0
1.6
0.2
0.6
3.4
25.5
4.4
11.6
41.5
0
7.3
6.0
13.3
2.2
7.1
39%
–14%
440%
1,600%
33%
–100%
120%
–9%
–59%
–27%
–22%
1.2
0.3
<0.1
1.5
0
0.4
0.8
1 .2
0
0.6
0.2
0.8
0
–13%
–42%
24%
–100%
0
12.7
7.0
17.9
<0.1
Cattle
Poultry
1996
16.3
1.0
<0.1
17.4
0
5.0
4.8
9.8
0
7.5
1.1
8.6
0
0
<0.1
<0.1
3.5
12.4
0.1
16.0
–45%
25%
–94%
–44%
–100%
50%
–28%
–70%
–100%
–18%
–55%
–41%
–71%
–14%
–99%
–50%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Swine
1.3
0.5
1.4
<0.1
1.9
Livestock
Units (000)
<0.1
14.5
12.1
14.4
5.6
32.1
Manure
(million L/yr)
1986
Poultry
1.3
1.1
0.9
Cattle
Swine
2.9
1.0
Poultry
Note: Blank areas represent no data available.
Niagara–on–the–Lake
Niagara Falls
Thorold
Welland
Pelham
Livestock
Units (000)
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
240
Walkerton Inquiry Commissioned Paper 6
AREA NAME
0
Swine
1.0
2.2
Cattle
Swine
0.5
0
Cattle
Swine
71.9
62.7
Cattle
Swine
1.7
12.1
10.9
Poultry
Cattle
Swine
24.7
18.8
Poultry
153.4
0.7
Poultry
1.2
8.5
Poultry
11.6
0
<0.1
Cattle
<0.1
Poultry
Note: Blank areas represent no data available.
Norwich
Oxford County
Grimsby
Lincoln
St. Catharines
Livestock
Units (000)
153.1
152.2
10.6
315.9
876.6
984.5
118.8
1,979.9
0
6.2
4.3
10.5
30.5
12.3
53.5
96.4
0
0.5
0
0.5
Manure
(million L/yr)
1986
9.3
12.7
0.5
22.4
56.4
66.5
13.7
136.6
0
0.2
0.9
1.1
2.0
1.2
11.6
14.8
0
0.3
<0.1
0.3
Livestock
Units (000)
1996
129.8
161.6
3.7
295.1
786.8
893.2
86.4
1,766.4
0
0.7
5.2
6.0
27.7
16.0
70.6
114.3
0
1.0
<0.1
1.0
–15%
6%
–65%
–7%
–10%
–9%
–27%
–11%
–88%
22%
–43%
–9%
30%
32%
19%
96%
97%
10.2
13.7
1 .8
25.7
65.5
67.7
8.9
142.2
0
0.3
<0.1
0.38
1.2
1.1
3.6
5.9
0
0
0
0
142.2
152.0
10.8
305.0
912.1
882.1
53.6
1,847.8
0
4.1
0.1
4.2
16.4
11.9
22.8
51.1
0
0
<0.1
<0.1
–7%
<–0.1%
1%
–4%
4%
–10%
–55%
–7%
–34%
–97%
–60%
–46%
–3%
–58%
–47%
–100%
–100%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
241
AREA NAME
14.5
Swine
22.7
16.3
Cattle
Swine
12.5
13.4
Cattle
Swine
11.7
7.5
Cattle
Swine
16.9
82.3
65.3
Poultry
Cattle
Swine
164.6
0.5
Poultry
19.7
0.5
Poultry
26.3
1.0
Poultry
40.0
0.5
13.0
Cattle
28.0
Poultry
Note: Blank areas represent no data available.
Wellington County
Blandford–Blenheim
East Zorra–Tavistock
Zorra
South–West Oxford
Livestock
Units (000)
914.6
1,079.9
104.7
2,099.1
105.2
154.6
3.2
263.0
188.4
172.2
3.1
363.7
227.1
321.1
6.3
554.5
202.8
184.4
3.4
390.6
Manure
(million L/yr)
1986
59.9
85.9
16.4
162.3
8.5
12.2
6.2
26.9
11.9
11.9
0.5
24.3
18.5
17.9
3.1
39.4
8.3
11.8
0.4
.5
Livestock
Units (000)
1996
835.2
1,096.5
100.5
2,032.3
118.9
155.9
37.9
312.7
165.4
162.3
2.8
330.6
256.9
249.3
19.4
525.7
115.7
164.1
2.6
282.4
–9%
2%
–4%
–3%
13%
1%
1,100%
19%
–12%
–6%
–11%
–9%
13%
–22%
210%
–5%
–43%
–11%
–24%
–28%
56.1
87.6
20.6
164.3
7.0
11.4
1.5
19.9
15.5
11.4
1 .5
28.4
19.3
18.4
2.3
39.9
13.6
12.7
0.6
26.9
787.5
1,093.8
128.8
2,010.1
97.4
140.9
9.1
247.4
215.8
156.8
8.8
381.4
268.4
257.6
13.3
539.3
188.3
174.7
3.3
366.3
–14%
1%
23%
–4%
–8%
–9%
180%
–6%
15%
–9%
180%
5%
18%
–20%
110%
–3%
–7%
–5%
–4%
–6%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
242
Walkerton Inquiry Commissioned Paper 6
AREA NAME
1.9
Swine
4.1
2.2
Cattle
Swine
5.7
3.5
Cattle
Swine
1.3
Cattle
Swine
<0.1
4.3
4.7
Poultry
Cattle
Swine
9.0
0.1
5.2
Poultry
6.6
<0.1
Poultry
9.3
<0.1
Poultry
6.3
0.1
3.6
Cattle
5.6
Poultry
Note: Blank areas represent no data available.
West Garafraxa
Erin
Eramosa
Guelph
Puslinch
Livestock
Units (000)
65.9
57.0
<0.1
122.9
18.8
63.7
0.5
83.1
49.4
75.7
0.1
125.3
31.2
50.4
0.1
81.7
27.2
39.9
0.6
67.8
Manure
(million L/yr)
1986
4.5
4.1
0.8
9.4
0.5
5.1
0.5
6.1
3.8
5.2
0.1
9.2
1.4
3.3
0.1
4.8
1.6
4.9
0.4
6.9
Livestock
Units (000)
1996
s63.0
49.7
4.9
117.6
7.9
59.0
2.8
69.8
51.9
67.2
0.9
120.0
19.6
42.9
0.5
63.0
23.0
51.7
2.3
77.0
–4%
–13%
41,000%
–4%
–58%
–7%
410%
–16%
5%
–11%
540%
–4%
–37%
–15%
330%
–23%
–16%
30%
250%
14%
4.2
3.6
0.3
8.1
0.5
5.2
0.6
6.3
0.8
4.6
<0.1
5.4
1 .1
1 .9
0.1
3 .1
2.7
3.1
0.3
6.2
60.2
42.9
1.9
105.0
7.2
59.4
3.7
70.4
11.0
57.8
0.2
69.0
15.9
22.9
0.6
39.4
38.6
34.3
1.9
74.7
–9%
–25%
16,000%
–15%
–62%
–7%
570%
–15%
–78%
–24%
37%
–45%
–49%
–55%
420%
–52%
42%
–14%
180%
10%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
243
AREA NAME
5.2
5.6
Cattle
Swine
21.0
Cattle
Swine
11.1
9.5
Cattle
Swine
2.1
9.8
5.9
Poultry
Cattle
Swine
17.8
3.6
Poultry
24.2
3.5
16.7
Poultry
41.2
0.3
Poultry
11.1
3.3
2.4
Cattle
Swine
5.7
<0.1
Poultry
Note: Blank areas represent no data available.
Minto
Maryborough
Peel
Pilkington
Nichol
Livestock
Units (000)
83.3
129.0
12.8
225.1
133.3
153.1
20.8
307.2
293.8
228.4
21.7
544.0
78.2
68.9
1.8
148.9
32.9
43.4
0.3
76.6
Manure
(million L/yr)
1986
5.7
11.2
1.3
18.2
8.4
10.9
3.0
22.3
20.1
18.2
2.3
40.7
5.3
5.8
0.3
11.4
2.1
3.6
<0.1
5.7
Livestock
Units (000)
1996
80.0
143.2
7.7
230.9
117.9
145.2
17.7
280.8
280.7
244.1
13.8
538.6
73.4
74.2
1.9
149.5
29.3
47.5
0.3
77.1
–4%
11%
–40%
3%
–12%
–5%
–15%
–9%
–5%
7%
–37%
–1%
–6%
8%
3%
<1%
–11%
9%
–1%
1%
5.0
11.2
0.7
16.9
8 .5
11.3
6 .5
26.3
18.6
20.8
2.9
42.3
5.8
5.6
1.0
12.4
3.2
3.7
0
6.9
70.6
139.4
4.4
214.3
118.9
149.2
41.2
309.3
259.4
268.3
17.9
545.6
81.4
72.8
6.4
160.7
45.2
43.8
<0.1
88.9
–15%
8%
–66%
–5%
–11%
–3%
98%
1%
–12%
17%
–18%
<0.1%
4%
6%
250%
8%
37%
1%
–100%
16%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
244
Walkerton Inquiry Commissioned Paper 6
AREA NAME
9.0
4.8
Cattle
Swine
4.4
2.4
Cattle
Swine
81.1
95.0
Cattle
Swine
4.4
3.9
Cattle
Swine
0.6
6.8
7.8
Poultry
Cattle
Swine
15.2
0.8
Poultry
9.0
12.8
Poultry
188.9
<0.1
Poultry
6.8
1.6
15.4
Poultry
Note: Blank areas represent no data available.
North Easthope
South Easthope
Perth County
West Luther
Arthur
Livestock
Units (000)
109.1
90.1
4.0
203.2
54.2
59.3
5.3
118.8
1,322.8
1,101.8
82.8
2,507.4
33.7
55.0
0.1
88.8
66.8
115.3
11.1
193.2
Manure
(million L/yr)
1986
8.2
6.7
1.0
15.9
3.8
4.4
0.7
8.9
102.2
79.3
13.9
195.4
1.3
3.0
<0.1
4.4
5.0
10.7
1.6
17.2
Livestock
Units (000)
1996
114.6
88.2
6.4
209.2
53.5
60.1
4.0
117.6
1,419.3
1,051.8
89.7
2,560.9
18.7
36.9
0.3
55.9
69.8
134.8
9.3
213.9
5%
–2%
60%
3%
–1%
1%
–24%
–1%
7%
–5%
8%
2%
–45%
–33%
300%
–37%
5%
17%
–16%
11%
9.3
6.3
0.8
16.3
3.3
4.2
<0.1
7.5
112.7
76.6
17.0
206.3
1.4
3 .8
0.1
5.3
4.2
11.3
2 .8
18.4
128.5
80.7
4.4
213.7
46.1
56.8
0.2
103.1
1,568.9
1,001.0
107.7
2,677.6
19.8
42.0
0.8
62.7
59.3
140.5
18.1
217.9
18%
–10%
10%
5%
–15%
–4%
–97%
–13%
19%
–9%
30%
7%
–41%
–24%
1,100%
–29%
–11%
22%
63%
13%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
245
AREA NAME
7.4
8.2
Cattle
Swine
4.2
4.3
Cattle
Swine
8.9
Cattle
Swine
4.3
6.9
Cattle
Swine
0.2
7.5
14.8
Poultry
Cattle
Swine
22.5
<0.1
Poultry
11.2
0.2
4.8
Poultry
13.9
1.0
Poultry
9.5
0.3
15.9
Poultry
Note: Blank areas represent no data available.
Logan
Hibbert
Fullarton
Blanshard
Downie
Livestock
Units (000)
206.0
100.2
1.4
307.7
94.9
60.6
0.1
155.7
123.4
67.1
1.2
191.7
59.4
57.1
7.5
124.0
113.3
101.9
2.2
217.4
Manure
(million L/yr)
1986
15.4
7.0
0.2
22.6
8.3
3.8
<0.1
12.1
10.0
4.1
0.2
14.3
5.0
5.2
2.0
12.3
10.4
6.8
<0.1
17.2
Livestock
Units (000)
1996
213.0
91.6
1.2
305.7
113.7
53.2
<0.1
166.9
138.5
54.5
1.3
194.4
69.2
65.8
14.5
149.5
143.4
92.6
<0.1
236.0
3%
–9%
–14%
–1%
20%
–12%
–76%
7%
12%
–19%
8%
1%
17%
15%
94%
21%
27%
–9%
–99%
9%
17.0
7.0
0 .2
24.3
9.4
2.5
<0.1
11.9
12.2
3.5
<0.1
15.7
2.7
3.2
0.5
6.4
10.4
7.1
0.8
18.3
236.5
93.1
1.4
331.0
135.0
31.5
0.1
166.6
170.4
46.7
<0.1
217.2
38.3
40.1
3.3
81.7
142.7
96.3
4.5
243.5
15%
–7%
–2%
8%
42%
–48%
–19%
7%
38%
–30%
–97%
13%
–36%
–30%
–56%
–34%
26%
–6%
110%
12%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
246
Walkerton Inquiry Commissioned Paper 6
AREA NAME
7.2
11.9
Cattle
Swine
10.4
Cattle
Swine
13.5
11.2
Cattle
Swine
10.7
6.8
Cattle
Swine
17.8
89.4
88.8
Poultry
Cattle
Swine
196.0
0.4
Poultry
17.9
5.1
Poultry
29.7
0.8
10.4
Poultry
21.6
0.5
19.7
Poultry
Note: Blank areas represent no data available.
Huron County
Wallace
Elma
Mornington
Ellice
Livestock
Units (000)
1,241.6
1,194.5
115.9
2,552.0
93.9
142.9
2.7
239.5
156.9
185.9
31.8
374.6
147.6
141.2
6.1
294.9
164.1
95.5
3.3
262.9
Manure
(million L/yr)
1986
90.9
84.2
21.8
196.9
6.4
10.5
1.4
18.3
9.5
13.6
3.6
26.7
10.0
10.8
0.9
21.6
15.3
6.5
0.4
22.2
Livestock
Units (000)
1996
1,267.2
1,078.8
141.0
2,487.0
89.3
134.7
8.5
232.4
134.3
182.5
22.8
339.6
139.6
144.9
6.3
290.9
210.3
83.8
2.5
296.5
2%
–10%
22%
–3%
–5%
–6%
220%
–3%
–14%
–2%
–28%
–9%
–5%
3%
5%
–1%
28%
–12%
–25%
13%
98.9
90.3
22.7
211.9
6.8
11.2
<0.1
18.0
10.2
13.6
4 .7
28.5
12.2
12.1
0.5
24.8
19.1
5.9
0.7
25.7
1,380.4
1,126.7
148.2
2,655.4
94.5
138.0
<0.1
232.5
143.7
182.6
28.2
354.6
171.4
s159.3
2.9
333.7
261.7
75.7
4.0
341.4
11%
–6%
28%
4%
1%
–3%
–100%
–3%
–8%
–2%
–11%
–5%
16%
13%
–52%
13%
60%
–21%
19%
30%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
247
AREA NAME
5.7
5.3
Cattle
Swine
5.3
7.4
Cattle
Swine
2.2
3.1
Cattle
Swine
3.6
6.8
Cattle
Swine
0.7
3.2
4.2
Poultry
Cattle
Swine
8.1
1.5
Poultry
11.9
0.4
Poultry
5.7
0.1
Poultry
12.7
0.7
11.7
Poultry
Note: Blank areas represent no data available.
Stanley
Tuckersmith
Hay
Stephen
Usborne
Livestock
Units (000)
57.7
43.0
4.4
105.1
94.6
47.2
10.9
152.7
43.1
27.2
2.4
72.6
103.9
72.6
0.5
177.0
73.6
84.4
4.3
162.3
Manure
(million L/yr)
1986
3.0
2.5
0.7
6.3
7.8
3.2
1.8
12.7
3.2
1.8
0.8
5.8
7.4
3.8
<0.1
11.2
4.3
3.6
0.7
8.7
Livestock
Units (000)
1996
42.2
32.2
4.8
79.2
108.4
41.5
12.7
162.6
44.2
21.3
5.0
71.0
104.2
50.7
0.3
155.1
59.7
50.3
5.1
115.0
–27%
–25%
8%
–25%
15%
–12%
17%
7%
4%
–22%
110%
–2%
<1%
–30%
–41%
–12%
–19%
–41%
17%
–29%
3.4
2 .7
1.3
7 .5
6.2
4.9
1.2
12.4
4.6
2.0
1.0
7.6
9.6
4.2
<0.1
13.8
6.5
4 .8
<0.1
11.3
47.5
34.1
7.5
89.0
87.0
66.8
9.1
162.9
64.2
21.6
6.9
92.7
136.3
54.9
0.1
191.3
90.0
64.8
<0.1
154.7
–18%
–21%
70%
–15%
–8%
42%
–17%
7%
49%
–21%
200%
28%
31%
–24%
–89%
8%
22%
–23%
–100%
–5%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
248
Walkerton Inquiry Commissioned Paper 6
AREA NAME
4.1
4.2
Cattle
Swine
2.4
Cattle
Swine
5.1
6.6
Cattle
Swine
5.4
8.1
Cattle
Swine
0.3
8.7
7.8
Poultry
Cattle
Swine
16.8
0.9
Poultry
14.4
3.4
Poultry
15.1
0.7
2.9
Poultry
6.0
2.6
10.9
Poultry
Note: Blank areas represent no data available.
Grey
McKillop
Hullett
Colborne
Goderich
Livestock
Units (000)
110.0
117.8
1.9
229.7
113.1
66.9
5.2
185.2
91.7
68.5
22.2
182.5
34.2
39.5
4.1
77.7
59.7
54.5
16.7
130.9
Manure
(million L/yr)
1986
9.5
9.1
0.7
19.3
10.0
5.7
0.8
16.4
6.7
5.2
4.9
16.8
1.5
2.6
0
4.2
5.4
3.9
2.8
12.1
Livestock
Units (000)
1996
131.3
122.0
4.1
257.5
138.4
70.7
4.5
213.6
94.3
65.9
32.2
192.5
21.4
35.2
0
56.6
75.3
49.3
17.7
142.3
19%
4%
120%
12%
22%
6%
–14%
15%
3%
–4%
45%
5%
–37%
–11%
–100%
–27%
26%
–10%
6%
9%
19.2
10.1
0.8
30.1
8.7
5.0
0 .5
14.2
4.6
4.5
4.3
13.4
2.0
2.7
0
4 .7
5.9
2 .7
3.0
11.6
268.5
129.4
4.8
402.7
121.8
58.0
2.9
182.8
64.2
ssss56.5
28.1
148.8
27.7
33.7
<0.1
61.4
82.0
33.5
17.9
133.4
144%
10%
152%
75%
8%
–13%
–44%
–1%
–30%
–18%
26%
–19%
–19%
–15%
–100%
–21%
37%
–39%
7%
2%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
249
AREA NAME
8.5
Swine
4.6
2.9
Cattle
Swine
6.8
Cattle
Swine
4.0
Cattle
Swine
0.2
4.8
2.5
Poultry
Cattle
Swine
7.5
0.1
6.3
Poultry
10.3
0.2
8.2
Poultry
15.3
<0.1
Poultry
7.5
0.4
11.9
Cattle
20.8
Poultry
Note: Blank areas represent no data available.
West Wawanosh
East Wawanosh
Morris
Turnberry
Howick
Livestock
Units (000)
35.1
61.7
1.0
97.9
55.0
83.8
0.4
139.3
95.1
107.5
1.2
203.8
40.8
62.2
<0.1
103.0
118.8
160.8
2.6
282.2
Manure
(million L/yr)
1986
2.4
5.6
0.2
8.2
3.7
6.1
0.1
9.8
7.3
8.5
0.2
16.0
2.4
3.8
2.3
8.5
9.2
11.7
1.1
22.0
Livestock
Units (000)
1996
33.0
68.2
1.1
102.3
51.4
78.0
0.3
129.7
101.7
108.5
1.2
211.4
33.5
46.2
14.1
93.8
128.4
151.8
6.8
287.0
–6%
10%
7%
5%
–7%
–7%
–18%
–7%
7%
1%
–6%
4%
–18%
–26%
37,000%
–9%
8%
–6%
170%
2%
2.5
5.7
0.3
8.5
2.0
6.7
0
8.8
7.1
8.7
<0.1
15.8
2.4
4.5
0.6
7.5
10.1
13.4
0.7
24.2
34.5
66.7
1.6
102.8
28.4
78.9
<0.1
107.3
99.7
108.1
0.2
207.9
34.0
55.5
3.3
92.7
140.9
170.4
4.1
315.4
–2%
8%
57%
5%
–48%
–6%
–100%
–23%
5%
1%
–86%
2%
–17%
–11%
8,500%
–10%
19%
6%
63%
12%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
250
Walkerton Inquiry Commissioned Paper 6
AREA NAME
7.4
8.3
Cattle
Swine
114.4
27.6
Cattle
Swine
13.3
4.9
Cattle
Swine
3.9
Cattle
Swine
0.1
5.3
2.8
Poultry
Cattle
Swine
8.1
0.1
8.5
Poultry
12.5
<0.1
Poultry
18.2
3.3
Poultry
145.2
0.6
16.3
Poultry
Note: Blank areas represent no data available.
Kinloss
Culross
Carrick
Bruce County
Ashfield
Livestock
Units (000)
39.5
66.4
0.3
106.2
55.2
113.4
0.6
169.2
68.6
174.0
0.3
242.9
387.4
1,505.4
21.5
1,914.2
115.2
96.9
3.6
215.7
Manure
(million L/yr)
1986
2.3
5.2
0.3
7.8
3.3
7.5
0.1
10.8
4.6
13.0
<0.1
17.6
22.9
111.6
4.5
139.0
7.1
7.0
0.6
14.8
Livestock
Units (000)
1996
32.0
63.1
1.9
96.9
46.2
90.9
0.3
137.5
63.9
164.5
0.2
228.6
321.6
1,390.5
27.9
1,740.0
99.2
87.1
3.7
190.1
–19%
–5%
480%
–9%
–16%
–20%
–39%
–19%
–7%
–6%
–31%
–6%
–17%
–8%
30%
–9%
–14%
–10%
4%
–12%
0.9
6.0
<0.1
6.9
3.2
9 .0
<0.1
12.2
3.8
13.6
<0.1
17.5
18.5
122.0
5.2
145.7
3 .8
7 .6
0.6
12.1
12.5
70.6
0.1
83.2
45.4
106.8
0.1
152.3
53.6
169.3
0.2
223.0
258.7
1,487.9
34.6
1,781.1
53.7
94.0
3.8
151.5
–68%
6%
–82%
–22%
–18%
–6%
–87%
–10%
–22%
–3%
–42%
–8%
–33%
–1%
61%
–7%
–53%
–3%
5%
–30%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
251
AREA NAME
9.0
2.8
Cattle
Swine
7.3
1.9
Cattle
Swine
8.6
2.4
Cattle
Swine
0.2
13.5
3.1
Poultry
Cattle
Swine
16.8
<0.1
Poultry
10.9
<0.1
Poultry
9.3
<0.1
Poultry
11.8
7.5
1.9
Cattle
Swine
9.3
<0.1
Poultry
Note: Blank areas represent no data available.
Brant
Greenock
Bruce
Kincardine
Huron
Livestock
Units (000)
43.3
177.8
1.3
222.5
33.3
113.6
<0.1
146.9
26.6
102.8
0.3
129.6
39.9
116.3
0.2
156.4
26.2
99.4
0.1
125.6
Manure
(million L/yr)
1986
2.2
13.8
1.0
17.0
1.2
8.5
0.7
10.5
1.4
6.6
<0.1
8.0
2.7
8.9
0.4
12.0
2.2
7.8
0.5
10.5
Livestock
Units (000)
1996
30.4
174.0
6.2
210.6
16.9
110.7
4.5
132.1
19.9
86.5
0.1
106.6
37.6
109.3
2.4
149.3
30.3
98.3
3.3
132.0
–30%
–2%
360%
–5%
–49%
–3%
30,000%
–10%
–25%
–16%
–43%
–18%
–6%
–6%
1,000%
–5%
16%
–1%
5,500%
5%
2 .1
14.1
<0.1
16.2
0.7
9.3
<0.1
9 .9
1 .5
6.7
<0.1
8 .1
1.9
9.3
0.5
11.8
0.5
6.8
0.9
8.2
29.6
174.5
<0.1
204.2
9.6
114.2
<0.1
123.8
20.4
80.7
0.1
101.2
26.6
112.9
3.1
142.6
7.0
84.6
5.9
97.5
–32%
–2%
–96%
–8%
–71%
11%
160%
–15%
–23%
–21%
–67%
–22%
–33%
–3%
1,400%
–9%
–73%
–15%
9,800%
–22%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
252
Walkerton Inquiry Commissioned Paper 6
AREA NAME
2.3
3.9
0.2
Cattle
Swine
10.1
0.7
Cattle
Swine
4.9
0.4
Cattle
Swine
<0.1
2.9
0.1
Poultry
Cattle
Swine
3.0
<0.1
Poultry
5.4
<0.1
Poultry
10.8
<0.1
Poultry
4.1
11.4
Cattle
Swine
13.8
<0.1
Poultry
Note: Blank areas represent no data available.
Albemarle
Amabel
Arran
Saugeen
Elderslie
Livestock
Units (000)
1.0
32.4
<0.1
33.4
5.5
59.0
0.1
64.6
9.2
134.2
0.3
143.7
3.5
53.6
<0.1
57.1
32.2
158.2
0.2
190.5
Manure
(million L/yr)
1986
0.3
5.6
<0.1
5.9
0.2
3.9
<0.1
4.2
0.9
10.2
<0.1
11.1
<0.1
3.5
<0.1
3.5
1.7
11.6
<0.1
13.3
Livestock
Units (000)
1996
3.9
34.9
0.1
38.9
3.1
44.0
0.1
47.3
12.5
134.9
0.2
147.6
0.1
42.0
<0.1
42.1
23.5
144.7
0.1
168.3
290%
8%
480%
16%
–43%
–25%
83%
–27%
36%
1%
–41%
3%
–98%
–22%
–30%
–26%
–27%
–9%
–61%
–12%
<0.1
3.9
<0.1
3.9
0.3
4.8
<0.1
5 .1
1.4
11.7
<0.1
13.1
0
3.6
<0.1
3.6
2 .2
14.1
<0.1
16.3
0.2
39.2
<0.1
39.4
4.0
55.6
<0.1
59.6
18.8
149.6
<0.1
168.4
0
23.6
<0.1
23.6
30.5
183.2
<0.1
213.8
–78%
21%
–10%
18%
–28%
–6%
–64%
–8%
104%
11%
–81%
17%
–100%
–56%
–49%
–59%
–5%
16%
–72%
12%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
253
AREA NAME
0
2.7
<0.1
Poultry
Cattle
Swine
2.7
5.5
0.2
Cattle
Swine
5.7
<0.1
Poultry
0.1
36.3
<0.1
36.5
2.9
68.0
<0.1
71.0
Manure
(million L/yr)
1986
0
2.1
<0.1
2.1
0
3.5
<0.1
3.5
Livestock
Units (000)
1996
0
24.9
<0.1
24.9
0
25.7
<0.1
25.8
–100%
–32%
4,500%
–32%
–100%
–62%
–3%
–64%
0
3 .2
0
3.2
0
6 .0
0
6.0
0
22.3
0
22.3
0
65.4
0
65.4
–100%
–39%
–100%
–39%
–100%
–4%
–100%
–8%
Manure % chg Livestock Units
Manure
Manure
Manure % chg
(million L/yr)
vs 1986
(000)
(million L/yr)
vs 1986
1991
Note: Blank areas represent no data available.
Source: Derived and calculated from census data (Canada, Statistics Canada, Agriculture, 1987, 1992a, 1992b, 1997).
Lindsay
Eastnor
Livestock
Units (000)
Table A4.6.1 Total Livestock Units and Manure Produced in Six Counties/Municipalities and Their Respective
Townships, cont’d.
254
Walkerton Inquiry Commissioned Paper 6
7,157
2,271
1,956
742
Oxford County
Elgin County
Kent County
Essex County
9,386
7,369
5,984
4,743
Huron County
Bruce County
Grey County
Simcoe County
Prince Edward County
Hastings County
966
1,980
54,090
8,813
Western Ontario Region
5,945
Perth County
7,920
Wellington County
Waterloo Regional Municipality
1,774
Dufferin County
968
1,035
Peel Regional Municipality
Halton Regional Municipality
33,791
Southern Ontario Region
6,978
1,316
Brant County
4,540
3,245
Haldimand–Norfolk Regional
Municipality
Middlesex County
3,883
Niagara Regional Municipality
Lambton County
1,689
Hamilton–Wentworth Regional
Municipality
Total N
(000 kg)
457
958
27,221
2,340
2,936
3,559
4,811
4,538
3,100
479
3,991
860
492
17,678
3,657
2,430
399
1,038
1,164
3,710
657
1,656
2,100
853
Total P
(000 kg)
1986
1,091
2,305
50,574
4,971
6,370
8,121
7,881
7,336
4,902
884
6,877
1,942
1,225
27,325
5,890
3,430
538
1,401
1,982
6,304
1,253
2,747
2,472
1,302
Total K
(000 kg)
894
1,836
51,342
3,896
5,578
6,763
9,178
8,919
5,868
955
7,615
1,460
1,019
31,613
6,391
4,140
683
2,117
2,337
6,360
1,249
3,058
3,634
1,597
Total N
(000 kg)
429
875
25,825
1,906
2,746
3,263
4,750
4,609
3,003
463
3,822
706
486
16,651
3,413
2,216
381
1,156
1,208
3,265
620
1,597
1,961
794
Total P
(000 kg)
1991
965
2,168
47,487
4,129
5,925
7,452
7,399
7,200
4,925
872
6,796
1,598
1,154
24,847
5,070
3,143
457
1,370
2,046
5,648
1,164
2,485
2,253
1,189
Total K
(000 kg)
–8%
–7%
–5%
–18%
–7%
–8%
–2%
1%
–1%
–1%
–4%
–18%
–2%
–6%
–8%
–9%
–8%
8%
3%
–11%
–5%
–6%
–6%
–5%
% chg. in
N vs 1986
767
1,681
51,904
3,759
5,565
7,005
9,814
9,296
5,674
579
7,768
1,372
927
31,485
5,762
4,113
529
2,507
1,954
6,485
1,063
3,008
3,534
1,873
Total N
(000 kg)
370
807
26,135
1,818
2,769
3,368
5,041
4,856
2,895
272
3,918
653
440
16,696
3,057
2,216
282
1,386
1,002
3,264
517
1,559
1,935
985
Total P
(000 kg)
1996
867
2,020
47,914
4,043
6,071
7,838
7,802
7,169
4,845
597
6,838
1,555
1,093
24,184
4,724
2,988
388
1,431
1,762
5,670
1,028
2,432
2,167
1,311
Total K
(000 kg)
–21%
–15%
–4%
–21%
–7%
–5%
5%
6%
–5%
–40%
–2%
–23%
–10%
–7%
–17%
–9%
–29%
28%
–14%
–9%
–19%
–7%
–9%
11%
% chg. in
N vs 1986
Table A4.7.1 Nitrogen, Phosphorus, and Potassium Production in Ontario Counties/Municipalities,
1986, 1991, 1996
The Management of Manure in Ontario with Respect to Water Quality
255
Appendix 4.7 Nitrogen, Phosphorus, and Potassium
Production in Ontario Counties/
Municipalities, 1986, 1991, 1996
1,379
1,199
1,244
2,351
Lanark County
Frontenac County
Lennox and Addington County
Renfrew County
1986
1991
2,010
9,517
1,111
718
519
621
1,116
1,212
1,708
2,247
6,785
143
9
19
568
1,553
1,026
956
1,085
Total P
(000 kg)
22,526
2,898
1,451
1,355
1,608
2,710
3,055
3,922
5,359
14,914
344
24
46
1,066
3,214
2,464
2,211
2,281
Total K
(000 kg)
–2%
<–1%
13%
–8%
–5%
<–1%
–6%
–1%
–2%
–10%
–5%
–45%
–55%
–13%
–9%
–12%
–4%
–5%
% chg. in
N vs 1986
–6%
4,194
19,580
2,359
1,402
1,099
1,316
2,337
2,540
3,474
4,654
13,887
295
20
40
1,153
3,136
2,147
2,005
2,185
Total N
(000 kg)
–6%
5,314
23,217
2,861
1,429
1,478
1,669
2,824
3,227
3,986
5,536
16,476
360
44
109
1,366
3,517
2,809
2,264
2,396
Total K
(000 kg)
5,061
2,134
9,674
1,111
595
566
654
1,109
1,285
1,720
2,290
7,640
150
17
43
641
1,705
1,167
1,002
1,125
Total P
(000 kg)
Ontario
127,827
64,372
122,920
120,669
60,830
114,858
Source: Derived and calculated from census data (Canada, Statistics Canada, Agriculture, 1987, 1992a, 1992b, 1997).
4,443
2,345
Leeds and Grenville United Counties
Northern Ontario Region
2,696
Ottawa–Carleton Regional Municipality
19,986
3,511
Eastern Ontario Region
4,768
Prescott and Russell United Counties
15,486
Stormont, Dundas and Glengarry
United Counties
Central Ontario Region
308
Parry Sound District
1,323
York Regional Municipality
36
3,461
Durham Regional Municipality
Haliburton County
2,441
Victoria County
90
2,086
Peterborough County
Muskoka District Municipality
2,289
Northumberland County
Total N
(000 kg)
119,234
4,173
18,350
2,452
1,333
1,110
1,208
2,023
2,284
3,117
4,358
13,210
248
27
60
1,088
3,011
2,207
1,890
1,995
Total N
(000 kg)
60,337
2,002
8,893
1,153
682
524
569
954
1,088
1,521
2,083
6,523
123
13
28
546
1,491
1,050
914
1,004
Total P
(000 kg)
1996
112,866
5,040
21,402
3,023
1,401
1,375
1,498
2,472
2,753
3,562
5,123
14,277
284
33
74
1,038
3,082
2,599
2,088
2,092
Total K
(000 kg)
–7%
–6%
–8%
4%
7%
–7%
–12%
–14%
–15%
–11%
–9%
–15%
–19%
–26%
–34%
–18%
–13%
–10%
–9%
–13%
% chg. in
N vs 1986
Table A4.7.1 Nitrogen, Phosphorus, and Potassium Production in Ontario Counties/Municipalities, cont’d.
256
Walkerton Inquiry Commissioned Paper 6
372
Wainfleet
308
408
West Garafraxa
Note: Blank areas represent no data available.
435
7,920
Wellington County
Erin
945
Blandford–Blenheim
Eramosa
1,242
East Zorra–Tavistock
283
1,975
Zorra
Guelph
1,317
South–West Oxford
235
1,108
Norwich
Puslinch
7,157
76
Grimsby
Oxford County
634
Lincoln
205
150
215
139
118
3,991
476
633
995
671
571
3,710
35
360
1
358
337
431
281
226
6,877
915
1,095
1,904
1,162
989
6,304
51
301
2
423
282
406
225
291
7,615
1,142
1,130
1,882
999
1,068
6,360
66
595
5
224
211
135
202
111
141
3,822
607
564
962
493
533
3,265
30
351
2
109
337
306
390
233
288
6,796
999
1,012
1,611
963
1,004
5,648
29
299
6
104
65
4%
–8%
–7%
–21%
24%
–4%
21%
–9%
–5%
–24%
–4%
–11%
–13%
–6%
180%
150%
–34%
358
291
260
13 9
257
7,768
932
1,308
1,894
1,240
1,105
6,485
17
283
<1
46
77
2
39
47
St. Catharines
50
101
1%
89
74
54
59
1,402
346
86
78
3,534
Niagara–on–the–Lake
76
35
–42%
–9%
–8%
–7%
40%
–6%
Total N
(000 kg)
154
74
96
973
262
82
62
2,253
% chg. in
N vs 1986
Niagara Falls
60
44
750
201
60
31
1,961
Total K
(000 kg)
44
35
90
1,448
344
129
62
3,634
1991
Total P
(000 kg)
73
111
1,131
303
88
55
2,472
Total N
(000 kg)
Thorold
75
868
204
64
21
2,100
Total K
(000 kg)
<1
157
1986
Total P
(000 kg)
Welland
Pelham
1,599
138
Port Colborne
West Lincoln
44
3,883
Fort Erie
Niagara Regional Municipality
Municipality
Total N
(000 kg)
181
141
125
70
128
3,918
466
666
947
620
559
3,264
8
197
<1
25
36
20
<1
28
732
170
40
36
1,935
Total P
(000 kg)
1996
286
312
299
132
213
6,838
862
1,063
1,642
1,097
1,005
5,670
21
162
<1
23
48
43
<1
65
954
260
66
55
2,167
Total K
(000 kg)
–12%
–5%
–40%
–51%
9%
–2%
–1%
5%
–4%
–6%
<–1%
–9%
–78%
–55%
–99%
–49%
–50%
–41%
–41%
–63%
–12%
–7%
–38%
75%
–9%
% chg. in
N vs 1986
Table A4.7.2 Nitrogen, Phosphorus, and Potassium Produced per Year, in Six Counties/Municipalities
and Their Respective Townships, 1986, 1991, 1996
TheThe
Management
Management
of Manure
of Manure
in Ontario
in Ontario
withwith
Respect
Respect
to Water
to Water
Quality
Quality
257
732
470
613
498
966
849
Downie
Blanshard
Fullarton
Hibbert
Logan
Ellice
585
583
246
567
372
Stephen
Hay
Tuckersmith
Stanley
9,386
Usborne
Huron County
856
703
North Easthope
Wallace
447
South Easthope
1,484
8,813
Perth County
1,041
312
West Luther
Elma
778
Mornington
889
Arthur
1,227
Maryborough
Minto
1,973
505
Pilkington
Peel
265
Nichol
Municipality
Total N
(000 kg)
201
303
132
298
304
4,811
430
762
535
436
501
253
318
249
374
361
224
4,538
154
382
455
601
995
259
132
Total P
(000 kg)
1986
298
392
191
486
531
7,881
836
1,236
906
667
732
411
478
386
645
593
383
7,336
311
709
802
1,019
1,583
440
255
Total K
(000 kg)
291
599
259
493
419
9,178
881
1,323
1,035
917
944
514
605
598
751
735
434
8,919
199
840
881
1,111
1,909
516
271
Total N
(000 kg)
161
320
137
254
222
4,750
435
673
529
473
489
264
317
330
382
376
214
4,609
97
408
431
544
955
261
134
Total P
(000 kg)
1991
229
384
176
374
346
7,399
815
1,157
915
655
694
391
434
463
621
597
380
7,200
202
798
842
941
1,614
463
271
Total K
(000 kg)
–22%
6%
5%
–16%
–29%
–2%
3%
–11%
–1%
8%
–2%
3%
–1%
27%
3%
5%
–3%
1%
–36%
8%
–1%
–9%
–3%
2%
2%
% chg. in
N vs 1986
352
610
33 3
596
506
9,814
807
1,385
1,131
1,031
1,016
504
64 5
300
812
715
356
9,296
226
937
803
1,374
1,998
562
291
Total N
(000 kg)
174
313
176
310
256
5,041
398
692
576
537
526
267
339
160
409
362
177
4,856
110
462
392
702
993
297
146
Total P
(000 kg)
1996
258
479
206
428
431
7,802
797
1,181
999
672
724
310
420
260
656
561
339
7,169
230
858
798
1,064
1,733
477
257
Total K
(000 kg)
–6%
8%
35%
2%
–14%
5%
–6%
–7%
9%
22%
5%
1%
5%
–36%
11%
2%
–21%
6%
–28%
21%
–10%
12%
1%
11%
10%
% chg. in
N vs 1986
Table A4.7.2 Nitrogen, Phosphorus, and Potassium Produced per Year, in Six Counties/Municipalities
and Their Respective Townships, 1986, 1991, 1996, cont’d
258
Walkerton Inquiry Commissioned Paper 6
997
359
697
488
353
735
7,369
888
617
375
471
575
492
553
846
738
229
577
248
128
278
146
Howick
Turnberry
Morris
East Wawanosh
West Wawanosh
Ashfield
Bruce County
Carrick
Culross
Kinloss
Huron
Kincardine
Bruce
Greenock
Brant
Elderslie
Saugeen
Arran
Amabel
Albemarle
Eastnor
Lindsay
381
3,559
432
303
185
226
279
237
267
410
353
108
273
118
60
131
69
176
241
351
177
498
401
1986
Total P
(000 kg)
288
147
402
326
628
8,121
951
637
377
528
626
552
614
949
847
278
698
297
158
341
183
353
483
646
357
955
720
Total K
(000 kg)
418
255
547
488
661
6,763
832
493
359
509
566
401
547
849
656
170
582
184
166
113
98
373
454
717
340
1,040
875
Total N
(000 kg)
607
197
886
707
330
3,263
404
242
176
256
273
193
261
414
313
80
276
87
79
53
46
184
225
358
186
522
443
1991
Total P
(000 kg)
309
97
465
360
563
7,452
893
507
357
540
598
454
600
934
766
212
698
221
197
142
143
382
448
654
300
945
766
Total K
(000 kg)
414
197
582
527
Source: Derived and calculated from census data (Canada, Statistics Canada, Agriculture, 1987, 1992a, 1992b, 1997).
791
Grey
Goderich
Colborne
Hullett
McKillop
Municipality
Total N
(000 kg)
579
300
777
638
–10%
–8%
–6%
–20%
–4%
8%
–2%
–18%
–1%
<1%
–11%
–26%
1%
–26%
29%
–59%
–33%
6%
–7%
3%
–5%
4%
11%
% chg. in
N vs 1986
5%
–34%
14%
11%
564
7,005
820
552
308
414
558
374
489
771
833
104
654
226
143
249
97
376
394
694
355
1,115
1,297
Total N
(000 kg)
562
204
723
598
276
3,368
396
269
147
215
267
180
232
368
397
49
311
107
67
117
46
189
191
347
173
554
665
1996
Total P
(000 kg)
286
101
367
306
542
7,838
903
582
355
454
606
420
590
898
973
130
777
274
179
311
122
378
428
639
333
1,038
959
Total K
(000 kg)
339
194
484
441
–23%
–5%
–8%
–10%
–18%
–12%
–3%
–24%
–12%
–9%
13%
–55%
14%
–9%
12%
–11%
–33%
6%
–19%
<–1%
–1%
12%
64%
% chg. in
N vs 1986
–3%
–32%
–7%
–6%
Table A4.7.2 Nitrogen, Phosphorus, and Potassium Produced per Year, in Six Counties/Municipalities
and Their Respective Townships, 1986, 1991, 1996
TheThe
Management
Management
of Manure
of Manure
in Ontario
in Ontario
withwith
Respect
Respect
to Water
to Water
Quality
Quality
259
366
613
392
1,259
1,983
133.0
217.5
132.8
206.0
219.8
1,394.8
Elgin County
Kent County
Essex County
Lambton County
Middlesex County
Southern Ontario
33.5
1,282.0
1,346
151.9
155.7
Grey County
Simcoe County
Western Ontario
Note: 1 hectare = 2.471 acres.
1,032
249.1
181.8
Huron County
Bruce County
1,921
15,718
675
4,057
2,592
78.2
180.4
Waterloo Regional Municipality
Perth County
401
3,290
157.0
Wellington County
Halton Regional Municipality
93
225
37.0
57.4
Peel Regional Municipality
Dufferin County
18,520
613
1,531
58.0
152.2
Brant County
Oxford County
5,877
2,558
67.9
162.4
Niagara Regional Municipality
Haldimand–Norfolk Regional
Municipality
2,650
45.2
Poultry
987
95
149
193
142
112
89
13
131
39
24
394
86
49
6
17
33
99
20
41
22
215
Cattle
1,511
64
49
76
405
461
207
3
230
13
5
1,137
226
218
27
188
59
268
28
63
38
22
Swine
Livestock Inventory (000 head)
Hamilton–Wentworth Regional
Municipality
1996
Total
Tillable
Hectares (000)
12.3
4.3
8.9
5.7
16.3
14.4
24.6
12.0
21.0
3.9
2.5
13.3
9.0
6.1
3.0
2.8
4.6
10.1
6.3
15.7
86.6
58.6
Poultry
0.77
0.61
0.98
1.06
0.57
1.14
00.6
.62
0.38
0.84
0.67
0.64
0.28
0.39
0.24
0.04
0.08
0.25
0.65
0.35
0.25
0.32
0.45
Cattle
1.18
0.41
0.32
0.42
1.62
2.55
2.64
0.08
1.47
0.22
0.12
0.81
1.03
1.06
0.21
0.87
0.44
1.76
0.48
0.39
0.56
0.48
Swine
# Livestock per Tillable Hectare
6.1%
2.7%
2.3%
3.5%
7.0%
12.3%
9.6%
2.3%
9.0%
2.0%
3.4%
4.8%
6.5%
5.3%
1.2%
3.2%
4.0%
11.6%
3.1%
2.5%
4.8%
3.8%
18.3%
14.9%
26.2%
21.3%
12.9%
16.9%
25.8%
10.0%
20.5%
16.0%
15.6%
8.0%
8.2%
5.8%
1.9%
2.5%
8.3%
12.3%
9.2%
13.3%
15.8%
12.5%
% of Tillable % of Tillable
Land Under Land Under
Liquid Manure Solid Manure
Table A4.8.1 Livestock Numbers per Tillable Hectare and Manure Application Method as a % of
Tillable Land, 1996
260
Walkerton Inquiry Commissioned Paper 6
Appendix 4.8 Livestock Numbers per Tillable Hectare
and Manure Application Method as a % of
Tillable Land, 1996
588
126
1,205
727
55.7
76.7
94.4
56.9
4.1
1.0
11.6
Peterborough County
Victoria County
Durham Regional Municipality
York Regional Municipality
Muskoka District Municipality
Haliburton County
Parry Sound District
1
1
12
0.4
0.6
10.8
12.9
0.88
0.87
0.75
0.83
0.74
0.02
0.02
0.31
0.11
0.12
0.13
4.0%
6.2%
11.9%
7.6%
2.4%
2.0%
0.0%
2.2%
1.4%
3.1%
1.3%
3.3%
18.2%
20.2%
12.7%
11.1%
11.0%
16.2%
21.3%
23.8%
17.4%
10.9%
18.7%
17.9%
18.4%
10.7%
13.8%
28
79
5
0.4
1.09
15.0%
14.8%
13.7%
19.9%
72.3
Renfrew County
38
32
30
7
1.7
0.73
0.13
1.7%
2.3%
2.8%
3.0%
17
21
433
43.0
37.1
40.1
56
10
7.7
0.71
0.23
0.13
0.09
0.13
0.19
0.19
0.20
0.39
0.04
0.36
6.0%
5.3%
5.2%
868
67.0
58
11
3.7
0.69
0.63
0.90
0.50
0.37
0.89
0.88
0.69
0.47
0.62
0.07
136
79.1
65
19
8.6
3.1
0.9
0.9
12.8
10.5
1.6
12.8
6.3
7.6
Eastern Ontario
569.7
2,767
458
67
4.9
0.80
0.12
Northern Ontario
178.5
288
124
8
1.6
0.69
0.04
Total Ontario
3,893.4
41,519
2,286
2,831
10.7
0.59
0.73
Denmark (1995 Census)
2,726.0
19,550
2,090
11,083
7.2
0.77
4.07
Indiana (1994)
6,475.1
26,400
1,170
4,500
4.5
0.18
0.69
Note: 1 hectare = 2.471 acres. Source: Canada, Statistics Canada, Agriculture, 1997; Indiana Agricultural Statistics, 1994; Danish Agricultural Council, 1999.
691
90.1
99
109
2
<1
1
11
11
15
37
2
26
21.3%
17.8%
15.0%
523
140.3
323
7
1
2
21
50
67
66
18
45
# Livestock per Tillable Hectare
Poultry
Cattle
Swine
2.9
0.80
0.10
% of Tillable % of Tillable
Land Under Land Under
Liquid Manure Solid Manure
1.3%
1.6%
3.3%
4,014
468.4
Central Ontario
Stormont, Dundas and Glengarry
United Counties
Prescott and Russell United
Counties
Ottawa–Carleton Regional
Municipality
Leeds and Grenville United
Counties
Lanark County
Frontenac County
Lennox and Addington County
36
1
4
239
543
58.3
38.1
71.6
Hastings County
Livestock Inventory (000 head)
Poultry
Cattle
Swine
167
47
6
Prince Edward County
Northumberland County
1996
Total
Tillable
Hectares (000)
Table A4.8.1 Livestock Numbers per Tillable Hectare and Manure Application Method, cont’d.
The Management of Manure in Ontario with Respect to Water Quality
261
262
Walkerton Inquiry Commissioned Paper 6
Appendix 4.9 Livestock Numbers, Livestock Units, and
Manure Production Predictions
Table A4.9.1 Livestock Numbers, Livestock Units, and Manure
Production Predictions for Swine
Swine
Boars (000)
1999
Sows (000)
14.0
% of Total
Other Pigs (000)
Total Head (000)
3,033
3,381
334
0.4%
9.9%
89.7%
100%
2000 Actual
13.4
319
2,897
3,229
2001 Forecast
13.8
329
2,985
3,328
2002 Forecast
13.9
331
3,002
3,347
2003 Forecast
13.9
333
3,020
3,366
2004 Forecast
14.0
335
3,037
3,385
2005 Forecast
14.1
336
3,054
3,405
2010 Forecast
14.5
346
3,140
3,501
Table A4.9.2 Livestock Numbers, Livestock Units, and Manure
Production Predictions for Cattle
Cattle
Beef
1999
% of Total
Bulls
(000)
26.0
1.3%
Dairy
Cows
(000)
Beef
Cows
(000)
All
Heifers
(000)
Steers
(000)
All
Calves
(000)
Total
Head
(000)
385
408
406
285
570
2,080
18.5%
19.6%
19.5%
13.7%
27.4%
100%
2000 Actual
25.6
379
402
400
281
562
2,050
2001 Forecast
23.9
354
375
373
262
524
1,912
2002 Forecast
23.4
346
367
365
256
512
1,869
2003 Forecast
22.8
338
358
357
250
501
1,827
2004 Forecast
22.3
330
350
348
245
489
1,785
2005 Forecast
21.8
323
342
340
239
477
1,742
2010 Forecast
19.1
283
300
299
210
420
1,531
The Management of Manure in Ontario with Respect to Water Quality
263
Table A4.9.3 Livestock Numbers, Livestock Units, and Manure
Production Predictions for Poultry
Laying
Hens in
Hatchery
Flocks
Laying
(000)
Hens (000)
Broilers
(000)
Pullets/
Pullet
Chicks
(000)
1996
22,775
4,152
8,669
% of Total
54.9%
10.0%
2000 Forecast
23,874
2001 Forecast
Turkeys
(000)
Other
Poultry
(000)
Total
Head
(000)
1,414
3,447
1,061
41,518
20.9%
3.4%
8.3%
2.6%
100%
4,353
9,088
1,482
3,614
1,112
43,523
24,140
4,401
9,189
1,499
3,654
1,125
44,008
2002 Forecast
24,407
4,450
9,290
1,515
3,694
1,137
44,494
2003 Forecast
24,673
4,499
9,392
1,532
3,735
1,150
44,979
2004 Forecast
24,939
4,547
9,493
1,548
3,775
1,162
45,465
2005 Forecast
25,206
4,596
9,594
1,565
3,815
1,175
45,950
2010 Forecast
26,537
4,838
10,101
1,647
4,017
1,237
48,378
Poultry
Table A4.9.4 Total Manure Production (million L/year)
Pigs
Cattle
Poultry
Total
2000
10,993
17,418
1,951
30,362
2001
11,328
16,242
1,973
29,543
2002
11,394
15,883
1,994
29,271
2003
11,459
15,523
2,016
28,999
2004
11,525
15,164
2,038
28,727
2005
11,590
14,805
2,060
28,455
2010
11,917
13,008
2,168
27,094
264
Walkerton Inquiry Commissioned Paper 6
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