What has changed from the previous draft of the rule?
The spatial extent of vulnerable groundwater areas are now smaller based on USDA NRCS soils data and karst geology. Counties within northwest Minnesota have been granted exemptions due to climate considerations. The applications of nitrogen fertilizer in the fall or to frozen soils is now restricted to quarter-sections of land in which more than 50% of the soils are defined as vulnerable as opposed to full sections.
The revised rule also expands exceptions for fall applications of MAP/DAP and other cops that may require fall nitrogen applications.
The new rule also focuses on public drinking water supplies known as Drinking Water Supply Management Areas (DWSMAs) and does not address private wells located within townships. MCGA had expressed concerns about using private wells as a basis for regulation without a dedicated groundwater monitoring network.
What areas still need clarification within the current draft?
MCGA will submit detailed comments on the rule, which will be available at mncorn.org. Those comments will focus on several areas needing clarification, including:
- Process and requirements on the verification of Best Management Practice (BMP) adoption.
- Methods and establishment of monitoring including both groundwater monitoring network and use of residual soil nitrate tests.
- How the regulatory enforcement levels change for cropland acres located within the DWSMAs.
- Details regarding Alternative Management Tools including how they will be identified and used to satisfy the BMP requirements.
Where did this rule come from?
The nitrogen fertilizer rule is based on the Minnesota Nitrogen Fertilizer Management Plan, which outlines the state’s strategy for preventing contamination and responding to elevated nitrate from fertilizer in groundwater. This plan first originated in 1990 followed by a three-year revision before being released in March 2015. The nitrogen fertilizer rule outlines the Minnesota Department of Agriculture’s (MDA) procedure to regulate nitrogen fertilizer use in vulnerable groundwater areas and areas of high concentration.
Does the MDA have the authority to regulate nitrogen applications?
The Minnesota Groundwater Protection Act of 1989 states that “the pollution control agency, of for agricultural chemicals and practices, the commissioner of agriculture, may adopt water resource protection requirements under subdivision 2 that are consistent with the goal of section 103H.001 and are commensurate with the groundwater pollution if the implementation of best management practices has proven to be ineffective.”
What parts of the state would be affected?
A vulnerable groundwater area includes coarse textured soils, karst geology, or shallow bedrock. The USDA NRCS soils maps were used to determine coarse textured soils and shallow bedrock. Fall and frozen soil applications of nitrogen fertilizer would be prohibited areas with vulnerable groundwater or drinking water supply management areas (DWSMAs) of a municipal public water supply well that are at or exceed 5.4 mg/L nitrate-nitrogen. The MDA estimates that the rule would apply to approximately 12-13% of cropland in the state.
Are groundwater nitrate levels elevated throughout these vulnerable areas?
Data collected thus far suggests that elevated nitrate levels do occur in some, not all, of the vulnerable groundwater areas. The MDA defines elevated levels as more than 3 mg/L nitrate-nitrogen. Public drinking water suppliers are required to deliver water that meets federal drinking water standards, including the nitrate-nitrogen standard of 10 mg/L or less. They are also required to test their source water wells annually, and if nitrate-nitrogen levels exceed 5.4 mg/L they must begin testing quarterly. About 30 communities in Minnesota are currently subject to this requirement. In addition, the MDA has found that about 10% of private wells in vulnerable groundwater areas exceed the federal drinking water standard, meaning that about 90% do meet the nitrate-nitrogen standard. Statewide, the Minnesota Department of Health reports that about 3% of all wells exceed the nitrate-nitrogen standard, indicating that about 97% do meet the standard.
If problems are rare, why impose this regulation?
The Minnesota Groundwater Protection Act establishes the following goal: “It is the goal of the state that groundwater be maintained in its natural condition, free from any degradation caused by human activities. It is recognized that for some human activities the degradation goal cannot be practically achieved.” While much emphasis has been placed on the drinking water standard, the MDA appears to be attempting to balance these two provisions by choosing to focus on the drinking water standard.
Is nitrogen fertilizer the only contributor to elevated nitrate levels?
The rule does not require that fertilizer be the only cause of elevated nitrate levels, only that it be a contributor. The Nitrogen Fertilizer Management Plan (NFMP) and the proposed rule provide for evaluation and consideration of other sources, most of which are or could be addressed through other regulations. The MDA’s authority applies only to nitrogen fertilizer.
Why doesn’t the proposed rule apply to manure?
The MDA’s authority includes agricultural chemicals only. Most manure applications are currently regulated by the Minnesota Pollution Control Agency.
Why not just apply the rule statewide?
The groundwater protection rule applies only to groundwater, not surface water, thus the rule is targeted to areas where groundwater is vulnerable to contamination. Throughout most of Minnesota, glacial till protects groundwater from contamination, thus there is no basis for including these regions in this rulemaking. Surface water is under the authority of the MPCA under the Clean Water Act and related Minnesota rules and regulations. In the Nitrogen Fertilizer Management Plan (NFMP), the MDA specifically notes that “areas with tile drainage are generally artificially drained because they have heavy soils with poor internal drainage, and tend to be less prone to nitrate leaching to groundwater.”
What will now happen with the township testing program for private wells?
According to the MDA, there will be no regulatory component for townships and voluntary township testing. Nitrogen Fertilizer Management Plan (NFMP) activities such as forming local advisory teams, promoting BMPs, and evaluating BMP adoption will continue to occur in townships. As noted in the statement of need and reasonableness (SONAR), “The MDA’s current proposed framework allows it to focus its resources on the highest priority areas affecting the greatest number of people, thus having the greatest impact on public health. The MDA will continue to work to implement the work set out in the NFMP for townships, including private well testing, development and promotion of nitrogen fertilizer BMPs, establishing monitoring networks were feasible, and helping to form local advisory teams to involve local famers and their advisors in water quality issues in their area.”