Environmental Consideration of Dairy Systems

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1 Environmental Consideration of Dairy Systems Phosphorus and Water Quality Neil Hansen, Colorado State University

2 Environmental Issues Agricultural nutrients in surface and ground water Greenhouse gas emissions Renewable Energy Microbial contaminants Antibiotics and hormones Dust Odor Viewsheds

3 Phosphorus Required Nutrient Water Quality Phosphorus losses of environmental importance are very small relative to phosphorus inputs in agriculture.

4 Eutrophication Nutrients stimulate algal productivity Decay of algae depletes oxygen Light penetration limited Aquatic plants O 2 depletion

5 Phosphorus Sources Minnesota Statewide Average Precipitation Year Streambank Erosion 7% Urban Runoff 4% Commercial Industrial Process Water 17% Dentrifaces 0% Roads/Sidewalks De-icing Chemicals 1% Commercial Automatic Dishwasher Detergent 1% Food Soils/Garbage Disposals 5% Non-agricultural Rural Runoff 5% Ground Water Intrusion 0% Ind. Sewage Treat Systems/Un-sewered Com. 5% Feedlots 1% Residential Aromatic Dish Detergent 3% Human Waste Products 15% Cropland and Pasture Runoff 23% Atmosphere Deposition 7% Agricultural Drainage 2% Raw/Finished Water Supply 1% Noncontact Cooling Water 0% Source: Phosphorus Sources To MN Watersheds, MPCA 2004 (Exhibit 5: 15) 5

6 Dairy Systems and Phosphorus Imported Bedding and Cleaning Supplies Bedding and Other Animal Products Sold Milk and Animals Feed Imported Feeds Animals Crops Sold Crops Manure Imported Manure Commercial Fertilizer Soil Runoff and Soil Erosion Manure Exported

7 MN Soils w/ Manure History Soil Phosphorus Analysis Manure No manure 65 ppm 21 ppm

8 Understanding Soil Phosphorus Stable P Reactive P Inorganic P Organic P Slow Inorganic P Organic P P in the Soil Solution

9 Total P Concentrations for selected MN Soils Bray P lbs P 2 O 5 /ac 5 ppm ppm ppm 450 Total P lbs P 2 O 5 /ac 450 ppm 2, ppm 2, ppm 3,100

10 Potential Total P Loss Bray P 5 ppm ppm ppm 1.4 lbs P/Ton Eroded Soil x 5 = 4.5 x 1 = 1.4 Accumulation of phosphorus in the soil increases the water quality risk Erosion control is even more important!

11 Cropping Systems Systems that include perennial forages reduce the risk of erosion and associated P loss relative to row crops. Conservation tillage approaches can likewise reduce erosion and associated P losses Balancing the farm P cycle can limit the accumulation of P on the farm Manure can improve soil physical properties and reduce erosion

12 Land Applied Manure Examples Solid Beef Manure Liquid Hog Manure Morris, MN

13 Solid Beef Manure

14 Solid Beef Manure

15 Liquid Hog Manure Runoff (in) Erosion (T/ac) Total P (lbs/ac) No Manure Manure

16 Cropping Systems Land applied manure is a valuable source of nutrients in cropping systems In addition, manure can improve soil physical properties and reduce erosion Manure can play a critical role in the sustainability of agricultural systems Environmental risk can outweigh benefits when manure is applied at high rates or at high frequencies

17 Manure Storage and Handling Feedlot issues continue to be at the forefront of regulation Phosphorus in Minnesota waters from crop and pasture runoff Current feedlot rules are tied up in court Lawsuits at all levels

18 Lawsuits Waco City, TX versus dairies in the North Bosque River watershed Phosphorus pollution of river and Lake Waco U.S. District Judge ruled that phosphorus in cow manure is a hazardous substance under federal environmental laws Oklahoma versus poultry companies in Illinois River Watershed Manure as a hazardous chemical substance or mixture phosphorus, nitrogen, arsenic, copper, zinc, hormones, antibiotics, and microbial pathogens

19 Hazardous substances Present an imminent and unreasonable risk of serious or widespread injury to health or the environment. Invokes broader legal oversight Solid Waste Disposal Act Most legal action focused on CAFOs Outcome affects all livestock producers

20 Contrasting Manure Handling Systems

21 Bedded Manure Pack Study

22 Nitrogen outputs from outdoor wintering of dairy cows Gasseous loss 31.8 % Milk N 19.6 % Manure N 32.4 % TN accumulation - soil 15.7 % Leaching and runoff 0.5 % 30 lactating cows; 120 days; 1.2 lbs N/cow/day; Total N inputs approx. 4,000 lbs.

23 Policy and Regulation should take systems view

24 Phosphorus Risk Index A tool to assess the risk of P movement from land to water at the field scale. Based on both P sources and transport factors. Widely used by states to regulate land application of manures.

25 Minnesota P Index Transport Mechanism Phosphorus Source Other Practice Factors Erosion (PP) c P Sources c Practice Factors = RISK Rainfall Runoff (DP) c P Sources c Practice Factors = RISK Snowmelt Runoff c P Sources c (DP) Practice Factors = RISK Overall Risk

26 Interpreting P Index Results P Index Score Relative Risk 0-1 Very Low None 1-2 Low None Management Recommendations 2-4 Medium Small Improvements 4-6 High Moderate Improvements >6 Very High Large Improvements

27 Effect of Erosion Rate (No P applied) P Index Value Erosion Rate 10 T/ac/yr 5 T/ac/yr 2 T/ac/yr Soil Test P (ppm)

28 Method of Manure Application (200 lb/ac P 2 O 5 fall manure, 10 ppm Olsen, 3.71 t/ac/yr erosion) 4 P Index Value 2 0 Inject Incorporate Surface P3 (Snow) P2 (Rain) P1 (Erosion)

29 Time of Manure Application (200 lb/ac P 2 O 5 manure, 10 ppm Olsen, 6.35 t/ac/yr erosion) 6 P Index Value 4 2 P3 (Snow) P2 (Rain) P1 (Erosion) 0 Fall Incorporation Winter Spread

30 Pope County Dairy Case Study 30

31 31

32 Phosphorus Index Scores Average Multiple Rotation Cycles (~15 yrs) Erosion Rainfall Runoff Snowmelt Runoff 8 6 PI d S Field Identification Number 32

33 P Index and soil P time trend to 2035 Field Soil Test P P Index Score P Index Score Soil Test P Year 33

34 P Index Scores - Field 2 Different Management Options Dorrich Dariy Field 2 P Index Scores Average Multiple Rotatation Cycles (~15yrs) Different Managment Options Erosion Rainfall Runoff Snowmelt Runoff 34 P Index Score Current Managment Vegetative Filter Sed Basin Fall Broadcast Manure w/ Incorporation Fall Broadcast Manure w/o Incorporation Manure Applied on Snow/Frozen Soil

35 How to Reduce Risk of P Losses Reduce winter applications of manure Incorporate or inject manure rather than surface apply Reduce rate of erosion through conservation tillage Reduce sediment delivery through use of buffer strips Reduce rate of P application, and credit manure applications

36 Concluding Remarks Individual livestock production systems can be designed in a site specific way to minimize P loss. No one system or type of system is best for all situations Regulatory oversight should take a systems view

NUTRIENT MANAGEMENT (ac.) CODE 590

IG-590-1 NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE INSTALLATION GUIDELINES NUTRIENT MANAGEMENT (ac.) CODE 590 GUIDELINES APPLICABLE FOR ALL PURPOSES Nutrient management activities shall