For more: http://www.extension.org/67684 The Wisconsin Discovery Farms Program was one of the first on-farm evaluation projects to identify the risk of manure applications in the late winter period. Data from several of our farms have shown that manure applied during February and March has an increased risk of running off and contributing to high nutrient losses in surface water. This data has been used to justify the establishment of recommendations, rules and regulations on winter manure spreading. But, do bans on winter manure spreading (spreading on frozen or snow covered ground) actually reduce the risk of manure runoff? A close evaluation of the data indicates that spreading during early winter (November - January) is much different than during late winter when frost can extend deeper and be more solid in the soil profile. Total winter application bans also increase the volume of manure that needs to be stored and increase the risk of runoff during the spring spreading season.
2. Key Lessons from DiscoveryFarms Timing, timing, timing
Management decisions really do matter Losses can vary greatly year
to year based onweather, location and management decisions Sound
conservation is still sound conservation
3. Wintertime runoff On average, 50% of runoff while soil is
frozen Can be 100% of total annual runoff dependingon conditions
Mostly February and March March: 100% frequency 1/3 of total annual
runoff Risk for runoff in April, May and June is similar tothat of
January and February