As of Sept. 1, 2020, 12.5 percent of Minnesota farmland cannot be applied with most types of commercial nitrogen in the fall or on frozen soil.

The implementation of nitrogen fertilizer restrictions is occurring about one year after the Groundwater Protection Rule was passed into law in June 2019.

“To protect and clean groundwater, that is our goal and we want to do that working with farmers on solutions that work for them locally,” said Margaret Wagner, manager of the Fertilizer Non-Point Section at the Minnesota Department of Agriculture.

Under the Groundwater Protection Rule, soils that are prone to leaching can no longer receive fall applications of nitrogen fertilizer.

An interactive map is available at the Minnesota Department of Agriculture that shows farmland down to the quarter section that can’t be fertilized with N in the fall.

The website location is:, or you can Google “Fall Nitrogen Fertilizer Application Restrictions (2020).”

Individuals can go in and look at that map, drill down to the quarter section level and look to see if their fields are restricted. The map shows a purple layer that indicates the vulnerable soils where the fall restrictions are in place.

A green layer indicates areas where the drinking water supply management areas have an elevated nitrate level.

“Please look on the map and see how this may impact your fields, and if there are any questions, look on our website or give us a call,” Wagner said. There is contact information listed on the website to call or e-mail, as well as at the end of this article.

Farmers are asking great questions confirming what they see on the map, as well as asking about manure applications or other plans for fieldwork this fall, she said.

Since 2018, the MDA has been communicating with crop advisors, farmers, co-ops, retailers and landowners about the new rule. About 600 letters were sent to local farmers and landowners affected by the rule. A webinar was given to answer questions, and 2,000 postcards were sent out to those affected.

There are rule exceptions that allow farmers to complete certain tasks. Fertilizer can be applied to establish winter grains planted in the fall; for fall pasture fertilization; when nitrogen is required for a perennial crop; for grass seed production, or for growing fall cover crops within a potato rotation to reduce applications of soil fumigants to future potato crops.

“Those exceptions were really developed because of a lot of the comments we got back during the public comment period and then responding primarily to farmer concerns about these individual cases or scenarios,” she said.

The fall-applied nitrogen restriction also doesn’t apply to northwest Minnesota due to climate factors that were considered.

Wagner said that farmers in the restricted areas have generally started following the rule.

“When you look at the University of Minnesota best management practices, fall fertilization is not recommended in these areas,” she said. “It may not make economic sense to apply in areas where there are going to be losses of nitrogen over the winter.”

Beginning Sept. 1, the owner, operator or the agent in charge of the cropland is responsible for assuring the rule is followed. Enforcement of the rule will be “complaint-driven.”

Information will be available on the Minnesota Department of Agriculture website for anyone that would like to call the complaint line, talk with a duty officer, or go online and submit a formal complaint.

The Department of Ag intends to approach enforcement with education and compliance assistance before moving to any financial penalty, Wagner said. They want to make certain people understand the rule and work with the department to comply. Any monetary penalty will be situation-specific based on the willfulness of the violation, the gravity of the damage, any history of past violations and the economic benefits to the individual.

“We feel that if we are working with farmers, we can develop locally-driven solutions that address these really complex issues,” Wagner said. “We acknowledge that complexity and we think working with the farmers, who are making the decisions on their land, is the best way to find solutions and really address this concern.”

The fall fertilizer restrictions are part one of a two part groundwater rule. The second part of the rule will focus on developing local advisory teams in drinking water supply management areas. These teams will include farmers, crop advisors, and stakeholders like cities and Soil and Water Conservation Districts to develop solutions on implementing changing practices where required.

Feel free to contact Margaret Wagner in the Pesticide and Fertilizer Management division at the Minnesota Department of Agriculture at 651-201-6488 or e-mail her at with any questions.