Preparing for field amendment when the time is right.
Manure and litter from feedlots and poultry houses are often stockpiled at the edge of a field to be available for land application when field conditions permit. It is important to recognize that field stockpiling is not an annual staging practice. In Michigan, suitable conditions may not last for long, so it is important that materials are ready to go when conditions permit. Selecting an appropriate place to stockpile these materials can minimize risks to surface and ground water and avoid potential nuisance issues for neighbors.
The Michigan Department of Environment Great Lakes and Energy (EGLE) regulations pertaining to manure or litter stockpiles of concentrated animal feeding operations (CAFOs) are equivalent to the practices dictated for manure application on these operations according to their permit.
EGLE regulations pertaining to manure management on CAFOs does not extend to manure or litter that is manifested to other persons, however the careful management of the material is still prudent. The following recommended practices include criteria listed in the Natural Resources Conservation Service Conservation Practice Standard Short-term Storage of Animal Waste and By-products, Code 318 and Michigan’s Generally Accepted Agricultural Practices (GAAMPs).
Stockpile only what is needed
When receiving materials from a neighboring farm or other source like a compost supplier, an analysis report should accompany the material. If not provided, a sample of the material should be submitted for nutrient analysis to your preferred lab. Use this nutrient data to determine an appropriate land application rate and only stockpile as much material in each field as was determined by that process.
According to GAAMPs, stockpiled manure must be spread onto fields within six months of initial pile placement if uncovered, or within twelve months if covered with an impermeable cover. Covering is recommended for the entire time the manure is stockpiled in the field.
Choose a location
Do not stockpile on grassed waterways or where water tends to pond or concentrate during precipitation events. Instead, choose an area that is high and dry and that does not drain towards a nearby water body or property boundary.
Choose a location for the stockpile that is:
- As far as possible – but at least 150 feet – from neighboring homes, roads or other sensitive areas to minimize the risk of neighbors experiencing odors and flies that could be associated with the stockpile.
- At least 150 feet from wells, springs, streams, ponds and other surface water.
- Where the seasonal high-water table will be no closer than two feet below the bottom of the stored material, unless a geosynthetic liner is used.
- On soils that are not likely to permit leaching of nutrients. Soils with higher sand content should be avoided unless the material is placed on a compacted soil pad, geomembrane lined pad or similar leachate barrier and the stockpile is covered.
- Where there are no groundwater spring, seep or subsurface drainage tile lines that could be contaminated by the stored manure.
- Placing a stockpile where neighbors or other sensitive areas (roads, public use areas, etc.) are directly downwind should be avoided.
Prevent and manage runoff
Liquid seeping from the piled manure, commonly called leachate, and precipitation coming into contact with the stockpile must be handled to prevent runoff from reaching neighboring properties or water bodies. Covering the pile with a tarp can help prevent runoff. If left uncovered, runoff from the stockpile area can be managed with an earthen berm or dike, grassed buffer area and/or silt fence. When using a grassed buffer area, at least 30 feet of vegetative buffer on the downslope side of the stockpile storage area is recommended for filtering solids in the runoff. Assess the site for the potential for runoff to create channel flow. If channel flow occurs, a 30-foot buffer will not be effective.
When initially placed in the field, stockpiles should be at least 6 feet high and have a conical shape. Moderate compaction of the pile and a sloped surface enhance the shedding of precipitation and lessen leaching.
Timely application of stockpiled manure and poultry litter on fields at agronomic rates and soil incorporation within 48 hours after application will help to control odors and will have nutrient management crop production benefits. Covering the pile with a tarp, a straw cover or additives such as lime, can be used to help reduce odors and pests.
Remember, stockpiling of manure should be a temporary storage method. A good temporary site will avoid neighbor nuisances, maintain good separation between the stockpile and both surface and ground water, and store materials for the shortest time possible.
For more information about field stockpiling or farm stockpiling contact Sarah Fronczak with Michigan State University Extension.
