Farm Horizons, Feb. 2016
Land-apply manure in winter requires extra care
By Lori Brinkman
Land-applying livestock manure in winter requires much greater attention to locations and weather. With increasing variability during winter, and attention to the weather even more so.
The main concern comes from insufficient incorporation, and runoff from frozen and snow-covered soil. (See article: “Research shows winter application of manure is a bad idea,” from the Conservation Technology Information Center).
For large livestock farms with state or federal operating permits, land application of liquid manure is prohibited after Nov. 30 on frozen or snow-covered soils, unless an emergency application is approved.
However, unlike last winter’s early freeze-up, some current measures at a 6-inch depth show soil temperatures at, or even above freezing.
When planning to land-apply either solid or liquid manure, applicators should always check soil conditions and weather forecasts. The Minnesota Department of Agriculture provides a webpage with links to soil temperature sites around the state.
Regardless of whether or not they have an operating permit, all livestock operations need to follow the Minnesota 7020 rules.
During winter land application, they must maintain a 300-foot setback from all sensitive features, and use other best management practices to prevent manure from running off, and preserving its nutrient value for next year’s crop.
For more information, see the fact sheet, “Managing manure land application during adverse weather conditions.”
Wisconsin farmers have access to the Manure Management System Advisory System map, which provides real-time weather information about runoff risk. The Minnesota Department of Agriculture is working on a similar map.
Some common-sense best management practices include:
• Manure is applied more than 300 feet from sensitive features, including lakes, streams, open tile inlets, sinkholes, water supply wells, mines and quarries, intermittent streams, un-bermed drainage ditches, or public water wetlands.
• No active snowmelt is occurring that can create runoff from an application field. Active snowmelt is deemed to be occurring if there are 2 or more inches of snow on the field, and maximum temperatures that exceed 40 degrees F. are occurring, or are predicted to exceed 40 degrees F. within 24 hours of spreading manure.
• No rainfall over 0.25 inches is predicted by the National Weather Service, with a probability greater than 50 percent within 24 hours of the end of the application period.
• Slopes should be less than or equal to 6 percent on the entire portion of the field where manure is land-applied.
• Water or ice should not occupy tillage furrows to the extent that additional snowmelt or precipitation cannot be contained between furrows or in other depressional storage areas within the field.