The rainfall rule for surface manure application in the WLEB is a weather forecast saying “not greater than a 50% chance of a half inch or more of rain in the next 24 hours”. It is advisable to print out the weather forecast when you start applying manure, so you have the needed proof if an unexpected storm drenches the area. Weather.gov is the most commonly accepted website for this forecast. On this web page, you can type in the zip code for a seven-day forecast. On the lower right-hand side of the seven-day forecast page, is an hourly weather forecast that will provide a 48-hour weather forecast graph.
Winter manure application rates should follow the Natural Resource Conservation Service 590 standards, which limit solid manure application amounts to five tons per acre and liquid manure application amounts to 5,000 gallons per acre. These have 200 foot setback distances from ditches, streams and creeks and must be on slopes of less than 6% and less than 20 acre areas in size without additional buffers. These setbacks exist because as snow melts, it can carry manure to streams and ditches. These 200 foot setback distances apply to both liquid and solid manure application. In recent years there have been several fines levied against livestock producers applying manure too close to ditches and streams.
For liquid manure applicators, examine fields for tile blowouts, monitor tile outlets before, during, and after manure application and any other situations that might allow manure to reach surface waters. If a cover crop has been planted, talk to the local Soil and Water Conservation District to determine of the cover crop has sufficient growth to meet the requirements.
Source : osu.edu