Greater Nitrogen Restrictions Proposed

Farmers in Minnesota could have more challenges when applying nitrogen, if a proposed rule becomes law. The Minnesota Department of Agriculture (MDA) is proposing the Nitrogen Fertilizer rule to minimize sources of nitrate pollution and expects adoption by the end of this year.

MDA held a public comment period this past year which are currently under review. The proposed rule is based on the state’s nitrogen fertilizer best management practices. There are two areas in which farmers can expect change:

  • Fall and frozen soil fertilizer restrictions
    • Nitrogen application will be restricted in areas that have vulnerable groundwater, meaning the nitrate can move easily through soil into the groundwater
    • If at least 50% of a section of land has vulnerable groundwater fall and frozen soil nitrogen application is not allow on the entire section
    • Exceptions for fall application in vulnerable areas include:
      • Areas applying nitrogen to establish small grains
      • To fertilize pasture
      • Apply phosphorus fertilizer (MAP, DAP) and other micronutrients that contain nitrogen so long as overall nitrogen rate doesn’t exceed 20 pounds per acre
      • Research in areas 20 acres or less
Vulnerable groundwater areas
  • Follow nitrogen fertilizer best management practices
    • This applies to areas identified as “nitrate contaminate groundwater” and starts with voluntary mitigation
      • There are four mitigation levels, the initial designation of a mitigation level is based on nitrate concentrations that are near to or exceed the nitrate health risk limit of 10 milligrams per liter
      • Mitigation areas will be defined with township boundaries or drinking water supply management area boundaries
    • Advisories teams will support implementing new practices and will reevaluate mitigation levels after 3 years
      • If BMPs are used on at least 80% of cropland in the designated area regulations will not be required, but if they’re not voluntarily used it can move into a regulatory level
Mitigation level criteria