The Minnesota Department of Agriculture (MDA) is reminding farmers and landowners that application of nitrogen fertilizer in the fall and on frozen soil is restricted in areas vulnerable to groundwater contamination and in Drinking Water Supply Management Areas (DWSMAs) with elevated nitrate levels. An area with vulnerable groundwater is an area where nitrate can move easily through soil and into groundwater. These areas include coarse textured soils, karst geology, and soils with shallow bedrock. A map showing where fall fertilizer restrictions apply as well as a list of exceptions to the fall fertilizer restrictions are available online at www.mda.state.mn.us/nfr.
The MDA announced updates to the fall nitrogen fertilizer restriction map in January 2022. These updates were made to correct GIS and data issues. As of January 2022, an additional 248,433 cropland acres and 603,654 non-cropland acres were added to the fall nitrogen fertilizer restriction map, while 4,659 cropland and 20,506 non-cropland acres were removed from the map. The Groundwater Protection Rule applies to cropland acres. The restrictions begin September 1 each year. Farmers are encouraged to check the new map prior to the fall of 2022 to determine if their fields are subject to these restrictions.
Fall nitrogen fertilizer restrictions are part of the Groundwater Protection Rule. The goal of the rule is to minimize potential sources of nitrate pollution to the state’s groundwater and to protect drinking water. The rule went into effect in June 2019 and the fall fertilizer restrictions started in September 2020. Fall fertilizer restrictions begin every year on September 1.
Local advisory teams, consisting of farmers, agronomists, local government staff, public water suppliers and other key stakeholders from the area, have been formed in most of the DWSMAs with elevated nitrate. Local advisory teams (LATs) are a key strategy to involve the agricultural community in problem solving to address localized concerns about unsafe levels of nitrate in groundwater. For each Level 2 DWSMA, the LAT is involved in reviewing, considering, and advising the MDA on appropriate practices to reduce nitrate loss in the DWSMA. Additional information is available at www.mda.state.mn.us/local-advisory-teams.
For more information in southeast Minnesota, contact Larry Gunderson at 651-201-6168, Larry.Gunderson@state.mn.us, in the Central and Southwest regions of the state contact Luke Stuewe at 218-850-9454, Luke.Stuewe@state.mn.us.