Winter application of manure is generally not recommended due to potential nutrient losses and water quality degradation. However, if you do need to apply manure this winter because of limited available storage capacity, there are several things to consider when applying to frozen or snow-covered ground in order to minimize runoff. Snow-covered is defined as soil having one inch or more of snow cover or one-half inch or more of ice cover.
If winter application of manure is unavoidable, consider when and where you apply to minimize the likelihood of runoff. Avoid applications before a snowmelt or rainfall event. Try to apply to ground with 4% slope or less and where soil erosion is controlled. Apply to areas with less snow cover. It is also recommended that you avoid application on land within 200 feet of (and draining into) a surface intake for a tile line. Also, avoid applying to grassed waterways and ditches that could transport the manure to water.
Confinement operations with more than 500 animal units have more restrictions regarding application to frozen or snow-covered ground than small confinements or open feedlots. Liquid manure application is prohibited between December 21 and April 1 if the ground is snow-covered, unless manure can be properly injected or incorporated the same date as it was applied. After February 1, large confinement producers are limited to emergencies only for applying liquid manure on frozen ground. Always follow your manure management plan or comprehensive nutrient management plan and update it if necessary to reflect surface application rates.
All applicators need to obey the separation distances for land application of manure, regardless of size of operation and time of year. Dry and liquid manure have the following separation requirements for surface application that is not incorporated:
- 200 ft. from a sinkhole, abandoned well, drinking water well, or water source unless there is a 50-foot buffer of permanent vegetated cover. Manure cannot be applied within the buffer.
- 800 ft. from a high quality water resource (a list is available from the Iowa DNR, there are several in Allamakee County).
- 200 ft. from an unplugged ag drainage well or ag drainage well surface inlet.
If you have specific questions about where and when to apply manure, please contact the DNR Manchester Field Office at 563-927-2640. If you would like to apply for financial assistance to construct a waste storage facility, please stop by the NRCS office at 635 9th St NW in Waukon.