The system assumes grid-wide average conditions for soil moisture. If you know that your fields are particularly wet (for example, you experienced a recent rainfall event that was greater than in other parts of the grid) you should know that the risk of runoff from your fields will be higher than what is shown on the risk map. The opposite may hold true if you estimate that your soil moisture values are lower than the grid-wide average.

Applying liquid manure (typically equivalent to 1/3 to 1 inch or more of rainfall) to wet fields can lead to direct manure runoff, even if the field is otherwise a low risk site due to low slope or low P-index. Make sure your fields are dry enough to accept additional moisture. If liquid manure should runoff or pond in a field or discharge into tile lines, application must stop until the runoff can be checked. Additionally, operating field equipment on wet fields can lead to soil compaction which can greatly reduce crop yields.

An application of 27,000 gallons per acre of liquid manure is the equivalent of adding approximately 1 inch of water to your fields. A liquid manure application effectively increases your soil moisture, and therefore the risk of runoff from fields receiving liquid manure will be higher than what is shown on the risk map.

These are areas of concern on your farm and might include fields with higher slopes, tighter soils, poor drainage, or fields that are closer to sensitive features such as ponds, streams, lakes, wetlands, sinkholes, etc. Many of these areas may be identified in your nutrient management plan. You should use caution when applying manure or any agrichemical products in these areas, regardless of what the risk map indicates.

If you must haul manure during high runoff risk times:

  • Use neighboring or other available manure storage facilities
  • Create in-field stacking in areas that pose the least environmental runoff risk

For manure storing guidelines, see Natural Resources Conservation Service’s “Conservation Practice Standard Waste Storage Facility, Code 313.”

Avoid field spreading manure
  • Use neighboring or other available manure storage facilities
  • Create in-field stacking in areas that pose the least environmental runoff risk

For manure storing guidelines, see Natural Resources Conservation Service’s “Conservation Practice Standard Waste Storage Facility, Code 313.”

No

Identify lower-risk fields for spreading or stacking manure:

  • Apply to your driest fields
  • Avoid sensitive areas of your fields.  For information on what options you have, see the MPCA Manure Management Plan
  • Use your Manure Management Plan or Nutrient Management Plan to find fields with:
    • low slope
    • low erosion, and
    • low delivery potential (low P-Index)
  • Apply to flatter fields without channelized flow, gullies
  • Apply to fields farthest from surface water, conduits to groundwater, and areas of concentrated flow
  • Apply to fields that do not drain to Outstanding, Exceptional, or nutrient impaired water bodies
If field spreading of manure is necessary

Identify lower-risk fields for spreading or stacking manure:

  • Apply to your driest fields
  • Avoid sensitive areas of your fields.  For information on what options you have, see the MPCA Manure Management Plan
  • Use your Manure Management Plan or Nutrient Management Plan to find fields with:
    • low slope
    • low erosion, and
    • low delivery potential (low P-Index)
  • Apply to flatter fields without channelized flow, gullies
  • Apply to fields farthest from surface water, conduits to groundwater, and areas of concentrated flow
  • Apply to fields that do not drain to Outstanding, Exceptional, or nutrient impaired water bodies
No

The MPCA Manure Management Plan restrictions:

  • No nutrient spreading in the winter within 300 feet of lakes, streams, intermittent streams, public waters wetlands, drainage ditches without berms, and open tile intakes.
  • Do not spread during snowmelt that creates runoff or when rainfall over ¼ inch is expected within 24 hours.
  • Only spread liquid manure to slopes less than 2 percent and solid manure to slopes less than 6 percent.
  • Only spread manure where tillage is on the contour (if slopes are greater than 2 percent).
  • Make sure to apply liquids at rates that prevent runoff during the application process.
  • Find alternative fields or management where MPCA determines that water will be polluted if you do spread.
In winter, follow these additional restrictions, from MPCA Manure Management Plan

The MPCA Manure Management Plan restrictions:

  • No nutrient spreading in the winter within 300 feet of lakes, streams, intermittent streams, public waters wetlands, drainage ditches without berms, and open tile intakes.
  • Do not spread during snowmelt that creates runoff or when rainfall over ¼ inch is expected within 24 hours.
  • Only spread liquid manure to slopes less than 2 percent and solid manure to slopes less than 6 percent.
  • Only spread manure where tillage is on the contour (if slopes are greater than 2 percent).
  • Make sure to apply liquids at rates that prevent runoff during the application process.
  • Find alternative fields or management where MPCA determines that water will be polluted if you do spread.
No
  • Use neighboring or other available manure storage facilities
  • Create in-field stacking in areas that pose the least environmental runoff risk

For manure storing guidelines, see Natural Resources Conservation Service’s “Conservation Practice Standard Waste Storage Facility, Code 313.”

Identify lower-risk fields for spreading or stacking manure:

  • Apply to your driest fields
  • Avoid sensitive areas of your fields.  For information on what options you have, see the MPCA Manure Management Plan
  • Use your Manure Management Plan or Nutrient Management Plan to find fields with:
    • low slope
    • low erosion, and
    • low delivery potential (low P-Index)
  • Apply to flatter fields without channelized flow, gullies
  • Apply to fields farthest from surface water, conduits to groundwater, and areas of concentrated flow
  • Apply to fields that do not drain to Outstanding, Exceptional, or nutrient impaired water bodies

The MPCA Manure Management Plan restrictions:

  • No nutrient spreading in the winter within 300 feet of lakes, streams, intermittent streams, public waters wetlands, drainage ditches without berms, and open tile intakes.
  • Do not spread during snowmelt that creates runoff or when rainfall over ¼ inch is expected within 24 hours.
  • Only spread liquid manure to slopes less than 2 percent and solid manure to slopes less than 6 percent.
  • Only spread manure where tillage is on the contour (if slopes are greater than 2 percent).
  • Make sure to apply liquids at rates that prevent runoff during the application process.
  • Find alternative fields or management where MPCA determines that water will be polluted if you do spread.
  • Improves soil quality and promotes carbon sequestration by building or maintaining soil organic matter
  • Protects surface water quality by reducing nutrient and sediment runoff (the organic matter in manure creates an open soil structure that stabilizes nutrients and lets water in more easily, reducing runoff)
  • Also protects surface water quality through manure application methods that prevent pathogens, nutrients and organic matter from entering waterways
  • May reduce the risk of groundwater contamination from nitrogen leaching compared to commercial fertilizers, as the nitrogen in manure is more stable and more easily utilized by crops
  • Reduces the risk of drinking water contamination by ensuring appropriate setbacks when applying manure near wells or in vulnerable drinking water supply management areas
  • Helps protect air quality by controlling odors from manure
  • Conserves energy compared to manufacturing, mining, processing and transporting of commercial fertilizers