BMPs

If mishandled, manure may contaminate water supplies with nitrogen, phosphorus, inorganic salts, organic solids and microorganisms. If present in sufficient quantities, those contaminants can cause considerable problems. Phosphorus (P) is one of the most common and serious surface water contaminants causing eutrophication. See the following publication for additional information on P:

Controlling runoff minimizes the potential of surface water degradation. Incorporation of manure greatly reduces the potential for nutrient runoff and minimizes odor as well as maximizing crop utilization of manure nutrients. If incorporation is not possible, apply manure to fields with growing crops or substantial crop residues. The surface cover will help slow overland flow of water, traps nutrients and minimize runoff. Avoid spreading manure on steeply sloping land or land close to surface water.

Riparian areas are transitional areas between upland and aquatic ecosystems. They need to be protected from grazing because they serve many functions in the landscape, such as controlling upland sources of non-point source (NPS) pollution.

The major concern with manure nutrient leaching is the movement of nitrate nitrogen to ground water. Several practices can minimize nitrate leaching from manure application. Most importantly, application rates should not exceed the nitrogen requirement of the crop.

Livestock and poultry producers should develop a nutrient management plan that first maximizes the use of manure nutrients and then supplements with commercial fertilizers only if additional nutrients are needed for the crop. The major elements of such a plan should include:

Periodic analysis of the manure produced in the animal operation
Routine soil testing program
Realistic yield goals for rate calculation
Accurate records of fields manured and the application rates used
Sufficient storage capacity
Field maps with sensitive areas identified
Proper timing of manure application
Calibration of manure spreaders so application rates can be determined

Rotate fields receiving manure to avoid nutrient buildup and maximize nutrient utilization;
Supplement commercial fertilizers only when manure nutrients do not meet crop yield goals;
Utilize a buffer area around water wells to prevent the possibility of waste transport to groundwater via the well or well casing;
Use grass filter strips along ditches and waterways to reduce soil erosion, runoff and nutrient losses;
Apply manure as close to the time crop utilization as possible;
Utilize fall cover crops to minimize soil erosion and runoff and to maximize nutrient utilization from manure application;
Avoid surface application of manure on steep slopes, frozen soil or near surface waters;
Avoid applying manure on wet soils to minimize compaction, runoff and leaching;
Calibrate application equipment to achieve accurate rates;
Maintain a stocking rate appropriate for the animal species and size of pasture or feedlot;
Unless immediately incorporated into the soil, surface apply manure at reasonable distances from residences and public buildings to reduce odor problems