Due to environmental concerns and nutrient losses, most Northeast states prohibit winter manure spreading without emergency exemptions, and only by following specific requirements. Some states have outlawed it altogether; others have differing definitions for winter.
Nonetheless, wintertime spreading is under intense scrutiny due to elevated risks for nutrient losses and its effect on water quality. So if it’s absolutely unavoidable, make sure you have clearance beforehand.
For Pennsylvania, winter is defined as any of the following three conditions:
1. Between Dec. 15 and Feb. 28
2. Any time the ground is snow covered
3. Any time the soil is frozen 4 inches or deeper
The dos and don’ts
The following guidelines must be followed by farms operating under a Manure Management Plan, which are typically smaller, less intensive operations. Concentrated animal feeding operations that are permitted or regulated under Act 38 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 ag drainage systems. Setbacks allowed in other seasons by implementing best management practices don’t apply during winter.
• Don’t: Spread on slopes greater than 15%. These would be soils listed with “D” or “E” codes on a soil survey map.
• Do: Limit winter application rates to the following: 5,000 gallons per acre of liquid manure; 20 tons per acre of solid non-poultry manure; 3 tons per 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% crop residue cover unless a cover crop has been planted there. Corn silage and low yielding soybean fields typically have less than 25% residue cover during the winter.
• Do: Prioritize winter spreading on fields with living plant cover, such as cover crops, hay fields or pastures. Plants in these fields help prevent nutrient losses by taking up nitrogen into plant biomass and more effectively preventing erosion.
Winter spreading is now a last resort — and only if legal. If that’s your situation, it’s time to increase your operation’s manure storage capacity. For more information about writing a Manure Management Plan, visit the Nutrient Management Education Program page.
Source: Penn State Extension