3 May 2009

4 minute read

The calf barn, the heifer shed, and dry cow facility all more than likely have some manure that needs to get cleaned out after a long winter. The question is what to do with that manure until the fields are dry enough to handle equipment to spread it. One option that a many farmers use is stockpiling the manure.  The Minnesota Pollution Control Agency (MPCA) recently came out with some guidelines for stockpiling manure that livestock producers should familiarize themselves with.

Stockpiling is one way of storing solidmanure (defined as having at least 15 percent solids content or be able to hold a 3:1 ratio when stacked) until it can be applied to cropland as fertilizer. Manure stockpiling sites are covered by the MPCA 7020 Rules (Feedlot rules) and are broken into two categories, short-term stockpiles and permanent stockpiles, depending on how long the stockpile is to be stored. Short-term stockpiles must have the manure removed and land-applied within one year of the date when the stockpile was formed; whereas, permanent stockpiles can be stored for over one year. The difference between the two, however, is that short-term sites do not need a permit if the owner of the manure is not the owner of the feedlot.  According to the feedlot rules, construction of permanent stockpile sites containing manure from facilities comprised of 300 to 999 animal units requires a construction short form permit.

General rules for stockpiles state that “they must be located and constructed such that manure-contaminated run-off from the site does not discharge into the waters of the state”.  As mentioned before, the stockpile must also contain at least 15% solids. This eliminates the possibility of stockpiling true liquid manure. It is important to note that the use of rock quarries, gravel pits, or mining excavation sites is prohibited.  Another point in the rules is that the size of the stockpile must not exceed a volume greater than the agronomic needs of the crops on the tract of land on which the stockpile is to be applied.

There are additional requirements for short-term stockpiles.  They include:

• Manure removal and land-applied within one year of establishment.
• A vegetative cover must be established for at least one full growing season before reuse.
• Cannot be located within 300 feet of flow distance to waters of the state, open tile intakes, any uncultivated wetlands that are not seeded to annual farm crops, or crop rotations involving perennial grasses or forages.
• Cannot be located within 300 feet of a road ditch that flows to any of the features listed above.
• Cannot be located within 100 feet of a drilled well or within 200 feet of an augered well.
• Prohibited on land with greater than 6% slope. Stockpiles are allowed on land with a slope between 2-6% as long as clean-water diversions and erosion-control practices are installed.
• Prohibited on soils where the soil texture to a depth of five feet (measured from plow depth) is coarser than a sandy loam as identified in the most recent USDA/NRCS Soil Survey Manual.

Recordkeeping: Short-Term Stockpile Sites

Recordkeeping is also a component of the use of short-term stockpiling. These records are to be kept on file for three years by the owner of the feedlot at which the manure was produced and be made available to the county feedlot officer or MPCA upon request.

These records should include information on:

• Location of each stockpile.
• Date that it was piled.
• Volume of manure in the stockpile.
• Nitrogen and phosphorus content of the manure.
• Date when the manure was land-applied.

If you are considering a permanent stockpile site, the manure needs to be placed on a cohesive soil pad. This means construction of a pad by remolding and compacting the soil so that the voids and lift interfaces are eliminated. This kind of work will require the assistance of NRCS or an engineer. Installing a liquid manure storage area may also be needed to collect and prevent manure-contaminated runoff from discharging to surface or ground water.

Stockpiling manure is often a necessary part of a livestock operation. If it is on your farm, take some time to familiarize yourself with the current laws and ordinances.

May 2009