Assess the risk for each field before a manure application

According to the Michigan Department of Agriculture and Rural Development (MDARD) Right to Farm Act’s Generally Accepted Agricultural Management Practices (GAAMPs) for Manure Management and Utilization:

1. All fields used for the production of agricultural crops should have soils sampled and tested on a regular basis to determine where manure nutrients can best be utilized.

2. Use current fertilizer recommendations, consistent with those of Michigan State University (MSU), to determine the total nutrient needs for crops to be grown on each field that could have manure applied.

3. To determine the nutrient content of manure, analyze it for percent dry matter (solids), ammonium N (NH4-N), and total N, P, and K.

4. The agronomic (fertilizer) rate of N recommended for crops (consistent with current MSU N fertilizer recommendations) should not be exceeded by the amount of available N added, either by manure applied, or by manure plus fertilizer N applied, and/or by other N sources. For legume crops, the removal value of N may be used as the maximum N rate for manure applications. The available N per ton or per 1000 gallons of manure should be determined by using a manure analysis and the appropriate mineralization factors for organic N released during the first growing season following application and the three succeeding growing seasons.

5. Records should be kept of manure analyses, soil test reports, and rates of manure application for individual fields. Records should include manure analysis reports and the following information for individual fields:

   1. soil fertility test reports;

   2. date(s) of manure application(s);

   3. rate of manure applied (e.g., gallons or wet tons per acre);

   4. previous crops grown on the field; and

   5. yields of past harvested crops.

6. Liquid manure applications increase soil moisture

   Liquid manure applications should be managed in a manner to optimize nutrient utilization and not result in ponding, soil erosion losses, or manure runoff to adjacent property, drainage ditches or surface water. Manure applications to crop land with field drainage tiles should be managed in a manner to keep the manure within the root zone of the soil and to prevent manure from reaching tile lines.

7. Snow-covered and frozen fields are higher risk areas

   Application of manure to frozen or snow-covered soils should be avoided, but where necessary, (a) solid manures should only be applied to areas where slopes are six percent or less and (b) liquid manures should only be applied to soils where slopes are three percent or less. In either situation, provisions must be made to control runoff and erosion with soil and water conservation practices, such as vegetative buffer strips between surface waters and soils where manure is applied.

If you must haul manure during high runoff risk times:

1. Avoid field spreading manure by:

   1. Using neighboring or other available manure storage facilities.

      Runoff storage facilities should be designed to contain normally occurring direct precipitation and resulting runoff and manure that accumulate during the storage times projected in the MMSP. In addition, storage volume should be provided that will contain the direct rainfall and runoff that occur as a result of the average 25 years, 24-hour rainfall event for the area. Storage facilities must be constructed to reduce seepage loss to acceptable levels.

      Where possible, do not locate manure storage in close proximity to residential areas.

   2. Creating in-field stacking in areas that pose the least environmental runoff risk.

      Solid manure that may contain bedding materials and/or is dried sufficiently, such as that from poultry, cattle, sheep, swine, horse, and fur-bearing animal facilities, can be temporarily stacked outside the livestock building.

      Stockpiling manure at a farmstead is an acceptable practice that should be protective of the environment and mindful of neighbors. Manure should be stockpiled on a hard surface pad (such as concrete or asphalt) with sides to prevent leachate and runoff. Stockpiling manure on the ground is also an acceptable practice with appropriate management such as rotating locations and complete periodic removal of manure from the location annually or more frequently, records documenting timing of removal and location used, and seeding of the previous location after removal to allow for vegetation to take up the nutrients that have accumulated in the soil. Stockpile locations should remain vegetated without stockpiled manure for a minimum of three years before reusing the site. In addition, the stockpile should be in a location that does not allow for runoff to flow onto neighboring property or into surface waters. The location should also consider odors and pests if the stockpile is in close proximity to homes, schools or other high use areas. Practices such as covering stockpiled manure with a tarp, fleece blanket1, straw, woodchips or other materials, or additives such as lime, can be used to help reduce odors and pests. Unless a tarp, fleece blanket, or straw cover is maintained, manure stockpiles need to be kept at least 50 feet away from property lines or 150 feet away from non-farm homes.

2. If field spreading of manure is necessary:

   1. Identify lower-risk fields for spreading or stacking manure:

      Manures should be uniformly applied to soils. The amount of manure applied per acre (gallons/acre or tons/acre) should be known, so manure nutrients can be effectively managed

      1. Apply to your driest fields

      2. Use your Nutrient Management or Conservation Plan to find fields with:

         1. Low slope

            As land slopes increase from zero percent, the risk of runoff and erosion also increases, particularly for liquid manure. Adequate soil and water conservation practices should be used which will control runoff and erosion for a particular site, taking into consideration such factors as type of manure, bedding material used, surface residue or vegetative conditions, soil type, slope, etc.

         2. Low erosion
         3. Low delivery potential (low P-Index)
         4. If the Bray P1 soil test level for P reaches 150 lb./acre3 (75 ppm), manure applications should be managed at an agronomic rate where manure P added does not exceed the P removed by the harvested crop. (If this manure rate is impractical due to manure spreading equipment or crop production management, a quantity of manure P equal to the amount of P removed by up to four crop years may be applied during the first crop year. If no additional fertilizer or manure P is applied for the remaining crop years, and the rate does not exceed the N fertilizer recommendations for the first crop grown). If the Bray P1 soil test reaches 300 lb./acre (150 ppm) or higher, manure applications should be discontinued until nutrient harvest by crops reduces P test levels to less than 300 lb./acre. To protect surface water quality against discharges of P, adequate soil and water conservation practices should be used to control runoff, erosion and leaching to drain tiles from fields where manure is applied.

   2. Incorporate manure applications whenever possible

      Incorporate manure into soil during, or as soon as possible after, application. This can be done by (a) soil injection or (b) incorporation within 48 hours after a surface application when weather conditions permit. Incorporation may not be feasible where manures are applied to pastures, forage crops, wheat stubble, or where no-till practices are used to retain crop residues for erosion control.

      1. Manure must be incorporated within 200 feet of areas draining to groundwater conduits

   3. Apply to fields farthest from surface water, conduits to groundwater, and areas of concentrated flow

      Manures should not be applied to soils within 150 feet of surface waters or to areas subject to flooding unless: (a) manures are injected or surface-applied with immediate incorporation (i.e., within 48 hours after application) and/or (b) conservation practices are used to protect against runoff and erosion losses to surface waters.