If winter manure spreading is unavoidable, take steps to limit water contamination risk
Spreading manure in the winter is discouraged because it is a high risk time period for nutrient losses and contamination of surface water. If wintertime manure spreading is absolutely unavoidable on your farm, following the regulations for winter spreading in Pennsylvania will help to reduce the risk of nutrient losses. Winter is defined as any of the following three conditions: between Dec. 15 and Feb. 28; or any time the ground is snow covered; or any time the soil is frozen four inches or deeper.
Below are guidelines that must be followed when spreading manure during winter periods. These guidelines apply to farms operating under a Manure Management Plan, which are typically smaller, less intensive operations. Concentrated Animal Operations that are regulated under Act 38 or permitted Concentrated Animal Feeding Operations should consult their Nutrient Management Plan to determine allowable winter spreading practices.
Do maintain a setback of 100 feet from streams, lakes, ponds, sinkholes, drinking water wells and aboveground inlets to agricultural drainage systems. The reductions in manure spreading setbacks around streams, lakes and ponds that are allowed in other seasons by implementing best management practices do not apply during the winter.
Don’t spread on slopes greater than 15 percent. These would be soils listed with “D” or “E” codes on a soil survey map.
Do limit winter application rates to less than or equal to the following: 5,000 gallons/acre of liquid manure; 20 tons/acre of solid non-poultry manure; 3 tons/acre of solid poultry manure. Alternatively, you can use a nutrient balance sheet to determine the phosphorus balanced rate of manure for the next crop and apply equal to or less than that rate.
Don’t spread on fields with less than 25 percent crop residue cover unless a cover crop has been planted there. Corn silage and low yielding soybean fields typically have less than 25 percent residue cover during the winter.
Do prioritize winter spreading on fields with living plant cover, such as cover crops, hay fields or pastures. The living plants in these fields will do a better job preventing nutrient losses during winter by taking up nitrogen into plant biomass and more effectively preventing erosion.
Do list the fields that will receive winter manure applications in the “Winter Application Worksheet” of your Manure Management Plan. Also make a note of the fields that will receive winter spreading on your farm map and indicate the slopes in those fields.
Winter spreading of manure is a practice that is under intense scrutiny because of the elevated risks for nutrient losses and its effect on water quality. Some states in the region have even outlawed winter manure spreading altogether. Increasing manure storage capacity to alleviate the need for winter spreading is the most preferred management practice. Use wintertime spreading as a last resort and be sure to follow the above guidelines to reduce the risk for nutrient losses when doing so.