The Groundwater Protection Rule is based on the Minnesota Nitrogen Fertilizer Management Plan (NFMP) which recommends steps for the prevention and minimization of the impacts of nitrogen fertilizer on groundwater, and emphasizes involving the local agricultural community in problem-solving for local groundwater concerns. A map showing which areas are subject to restrictions on fall application and application to frozen soil is also available.
The Groundwater Protection Rule is based on the Minnesota Nitrogen Fertilizer Management Plan (NFMP). The NFMP outlines the state strategy for preventing contamination and responding to elevated nitrate from fertilizer in groundwater. The rule sets out the procedures by which the Minnesota Department of Agriculture may regulate the use of nitrogen fertilizer in vulnerable groundwater areas to prevent contamination from occurring and to respond to areas that have high nitrate concentrations.
Nitrate is one of the most common contaminants in Minnesota’s groundwater. The majority of Minnesota households have access to safe drinking water supplies. However, in areas vulnerable to groundwater contamination, some public and private wells have nitrate levels that exceed the health risk limit for nitrate. While elevated levels of nitrate in groundwater can result from several factors, a major contributor in rural Minnesota is nitrogen fertilizer that leaches past the crop root zone.
There is an extensive body of research documenting that nitrate from nitrogen fertilizer can leach below the root zone and migrate to groundwater. While contributions from soil organic matter, manure applications, and legume crops do occur, fertilizer inputs are recognized as the most important in terms of management options. Fertilizer as Source of Nitrate in Groundwater contains more information and a listing of relevant research articles and reports.
Public water supply wells are monitored for water quality under the Safe Drinking Water Act administered by the Minnesota Department of Health (MDH). This data is used by the MDA and MDH to evaluate nitrate levels and water quality trends. The MDA may also install a local groundwater monitoring network in a Drinking Water Supply Management Area (DWSMA).
The purpose of the rule is to minimize potential sources of nitrate pollution in the state’s groundwater and to protect our drinking water. The rule is one tool, for specific situations, that is part of a larger strategy to reduce nitrate from fertilizer in groundwater.
The authority for the rule comes from the Minnesota Groundwater Protection Act, Minnesota Statute 103H. The Minnesota Department of Agriculture (MDA) has the authority to issue administrative, civil, and criminal penalties against those who violate the rule under Minnesota Statute 18D.
The rulemaking process is a process that all state agency's must follow when adopting rules. The MDA published the Groundwater Protection Rule on April 30, 2018. Written comments on the rule can be submitted via the Office of Administrative Hearings website. Five rule hearings will be held before an administrative law judge (ALJ) in the summer of 2018. More details on these hearings. After the rule hearings the ALJ will issue a report. Based on the judge’s report, the MDA may need to revise the rule or redo portions of the rule. The MDA anticipates adoption of the rule in December 2018 with the fall fertilizer application prohibition going into effect January 2020.
There are two parts to the rule. Each part contains separate provisions. Depending on where you farm, you may be subject to one part of the rule, both parts, or neither part.
Part 1: You are subject to Part 1 of the rule if you farm in a vulnerable groundwater area or in a Drinking Water Supply Management Area (DWSMA) that has 5.4 mg/L or higher of nitrate. This means you cannot apply nitrogen fertilizer in the fall and on frozen soils in those areas.
Part 2: You are subject to Part 2 of the rule if you farm land in a DWSMA with elevated groundwater nitrate concentrations. These areas will be designated a mitigation level 1, 2, 3 or 4.
See the answer to Question 13 for more detailed information.
A vulnerable groundwater area is land where nitrate can move easily through soil and into groundwater. The criteria used to determine vulnerability include coarse textured soils, karst geology, or shallow bedrock. The USDA NRCS soils maps were used to determine coarse textured soils and shallow bedrock. A Minnesota Department of Natural Resources Pollution Sensitivity of Near-Surface Materials Report was used to identify the locations of karst.
The application of nitrogen fertilizer in the fall or on frozen soils will be restricted in areas with vulnerable groundwater or DWSMAs that are at or exceed 5.4 mg/L nitrate-nitrogen. An area with vulnerable groundwater is an area where nitrate can move easily through soil and into groundwater.
The criteria used to determine vulnerability include coarse textured soils, karst geology, or shallow bedrock. The map on this page shows where fall application of nitrogen fertilizer will be restricted. Vulnerable quarter sections are shown in purple and DWSMAs are in green on the map.
More detailed maps showing vulnerable areas are available.
In areas where 50% or more of the quarter section has vulnerable groundwater or is in a DWSMA, applications of nitrogen in the fall and on frozen soils will not be allowed in the entire quarter section. If less than 50% of the quarter section has vulnerable groundwater, the restrictions do not apply.
Fall application of nitrogen fertilizer will be allowed in vulnerable groundwater areas to:
There are additional exceptions and exemptions related to: presence of clay soils with ultra-low permeability; in areas with reduced leaching potential combined with a short spring planting season; and, in counties with less than 3% of the land in row crops.
Ammoniated polyphosphate (MAP and DAP) and micronutrient formulations containing nitrogen can be applied as long as the applied rate does not exceed an average of 40 pounds of nitrogen per acre. Fields with low or very low phosphorus are exempt from this restriction.
Fall nitrogen fertilizer applications will also be allowed for agricultural research and demonstrations for academic purposes, provided the area is limited to 20 acres or less, or approved by the Commissioner of Agriculture.
These restrictions will not take effect until January 1, 2020.
Mitigation is the action of reducing the severity of a problem. In addressing the problem of nitrate contamination, mitigation levels will be based on nitrate data collected from public wells.
Mitigation Levels 1 and 2:
The initial designation of mitigation levels for a DWSMA is based on nitrate concentrations that are 5.4 mg/L nitrate-nitrogen or higher. Nitrate data from public wells will be used to prioritize areas of greatest concern and to determine if mitigation is necessary. All areas identified with elevated nitrate contamination will begin in a voluntary mitigation level 1 or 2.
Level 2 Mitigation designations (DWSMAs that have reached or exceeded 8 mg/L nitrate-nitrogen at any point over the past ten years) will be reevaluated after no fewer than three growing seasons, using nitrate concentration data collected from public wells and surveying the effectiveness of nitrogen fertilizer best management practices (BMPs).
Mitigation Levels 3 and 4 (regulatory):
A Level 2 site will progress to level 3 if one of the following occurs: 1) after three growing seasons the BMPs are not adopted on 80% of the cropland acres (excluding soybean acres); or 2) after three growing seasons the residual soil nitrate below the root zone increases; or 3) after three growing seasons or the estimated lag time, whichever is longer, the nitrate concentrations continue to increase. The Commissioner of Agriculture – in consultation with a local advisory team – would then require landowners to implement best management practices, testing, and educational programs.
If nitrate in the public water supply well exceeded 9 mg/L nitrate-nitrogen for any three samples in the previous 10 years; or after three years the residual soil nitrate below the root zone increases; or after three years or the estimated lag time, whichever is longer, the nitrate levels continue to increase, then the DWSMA would be given a Level 4 designation. The Commissioner of Agriculture – in consultation with a local advisory team – could require landowners to implement additional practices beyond best management practices. These practices would be determined on a site specific basis following guidance outlined in MN Statutes Chapter 103H.275 Subd. 2(a). However they may not include restrictions on the primary crop or restrictions on fertilizer rates below the low end of the University of MN recommended fertilizer rate range.
The Minnesota Department of Agriculture (MDA) has the authority to regulate nitrogen fertilizer; the Minnesota Pollution Control Agency (MPCA) has the authority to regulate manure.
The rule calls for following the nitrogen fertilizer BMPs. One of the BMPs is to properly credit all nitrogen sources, including manure, when determining the nitrogen fertilizer rate.
If the nitrogen fertilizer best management practices (BMPs) are implemented on more than 80% of the cropland in your area, and residual soil nitrate levels do not increase, or nitrate levels in the public water supply do not increase, then regulations will not be required. Otherwise the Drinking Water Supply Management Area (DWSMA) can move to a regulatory level.
In cropland areas with high nitrate concentrations in the groundwater, the MDA strongly encourages farmers to consider using Alternative Management Tools (AMTs). In the rule, Alternative Management Tools are defined as “specific practices and solutions approved by the commissioner to address groundwater nitrate problems.” Examples of AMTs include, but are not limited to, type of precision agriculture, nitrification inhibitor, cover crops, annual crops, and alfalfa. The MDA will maintain a published list of approved AMTs. This list will be updated on an annual basis. Under the Groundwater Protection rule, land with AMTs in place will be considered BMP compliant in the BMP survey.
Non-compliance with the Groundwater Protection Rule will generally first be addressed by providing compliance assistance to the landowner. Except for cases that involve human endangerment, the general progression of penalties involves 1) education, 2) compliance assistance, and 3) enforcement.
The MDA has the general authority to issue administrative, civil, and criminal penalties for violations of its rules through Minnesota Statutes 18D. Penalty actions are based on the severity of the violation and the facts of the case. The MDA takes a progressive enforcement approach, meaning that repeat violations will be met with stronger penalties than first violations.
The only parties possibly subject to penalties would be those in violation of the fall/winter nitrogen fertilizer application restriction and those who violate a Commissioner’s order for mitigation Level 3 and Level 4. If a regulated party disagrees with a proposed penalty, the party will have the opportunity to challenge it.
Fertilizer Technical Unit Supervisor
Pesticide & Fertilizer Management Division