Minnesota will regulate commercial nitrogen fertilizer beginning in 2020, when the Minnesota Groundwater Protection Rule goes into effect.
Graphic courtesy of MPCA
The rule, based on the Minnesota Nitrogen Fertilizer Management Plan that originated in 1990, applies to two categories of water resources—vulnerable groundwater areas and Drinking Water Supply Management Areas (DWSMAs) (Minn. R. Ch. 1573).
The rule restricts fall application of nitrogen in the areas of the state where vulnerable groundwater areas are located, and requires best management practices and alternative management practices in DWSMAs where nitrogen concentrations are above levels specified in the rule.
Larry Gunderson is the acting section manager of the Fertilizer Non-Point Section at the Minnesota Department of Agriculture (MDA) which will implement the rule. He explains: “There are two parts to the rule, the first affecting the application of nitrogen fertilizer in the fall and on frozen soils in vulnerable groundwater areas. This goes into effect September 1, 2020. The second part of the rule responds to DWSMAs with high nitrate.”
Graphic courtesy of MPCA
Limited fall and frozen soil application in vulnerable groundwater areas
The rule limits nitrogen fertilizer application in vulnerable groundwater areas – defined based on soil type (coarse textured soils) or geological features (shallow bedrock or karst geology) – or where a municipal public water supply well is already threatened with nitrate-nitrogen contamination. (Minn. R. 1573.0010, subp. 23; Minn. R. 1573.0030, subp. 1(A)).
Where vulnerable groundwater areas constitute 50 percent or more of a quarter section or government lot, farmers are prohibited from applying nitrogen fertilizer in the fall (after August 31) or when the soil is frozen (to a depth that does not allow placement and incorporation of nitrogen fertilizer at least three inches below the soil surface). (Minn. R. 1573, subp. 1(A)(2)).
Broader implications of the rule
RRWMB Executive Director Robert Sip on State Hwy 9 north of Beltrami, MN, spring 2019
Robert Sip, Executive Director of the Red River Watershed Management Board (RRWMB), comments, “In the Red River Basin, the rule does not appear to have much immediate effect unless you farm in the beach ridge area of Glacial Lake Agassiz.”
“This area of the basin can have coarse-textured soils compared to the heavier soils to the west and outside the beach ridges. The soil type and depth of clay in most of the basin makes it less likely that nitrogen will leach into groundwater," adds Sip.
"Farmers in the basin are readily using precision agriculture technologies and best management practices to reduce or eliminate potential groundwater issues.”
“Farmers in the basin are readily using precision agriculture technologies and best management practices to reduce or eliminate potential groundwater issues.”
BdSWD Administrator Jamie Beyer
Jamie Beyer, administrator of the Bois de Sioux Watershed District (BdSWD), echoes the positive implications of farming best management practices for water resources.
“Over the past 18 years, agriculture has continued to evolve and improve, and technology continues to be adopted by farmers as it develops,” says Beyer.
“At great expense to their own operations, Minnesota’s farmers can make fertilizer decisions based on regular soil sampling results, apply fertilizers using custom rates that vary within fields, and deliver fertilizer in smaller, just-in-time doses to match what the plants need. But, due to the lag time between what happens at the surface and the corresponding impact on groundwater, these improvements may not be fully realized for 20 years.”
“Over the past 18 years, agriculture has continued to evolve and improve . . . but, due to the lag time between what happens at the surface and the corresponding impact on groundwater, these improvements may not be fully realized for 20 years.”
Joe Magner, University of Minnesota research professor in the Department of Bioproducts and Biosystems Engineering, agrees that farming technology is constantly changing and improving, and offers a different angle on the effects of the rule.
“From my perspective, the rule has gotten crop consultants and local cooperatives to think about the future in terms of their business model and the products they are selling,” comments Magner.
“The rule is causing them to think about the services they are providing because they can’t keep pushing nitrogen product out the door. That model can’t work anymore from a local business perspective. Cooperatives are changing to rely more on the services that they sell rather than the products that they sell. Strategic application and the precision of agricultural application is in part driving the change, and the rule has created motivation for industry practice shift.”
Graphic courtesy of MPCA
Voluntary BMPs sought for DWSMAs
Gunderson explains that, after a few years, the rule will limit fall and frozen soil application of nitrogen fertilizer on DWSMA land.
“There are four mitigation levels used to determine voluntary and regulatory actions, two voluntary levels and two regulatory levels,” says Gunderson. “All areas will begin at a voluntary level and move to regulation only if the best management practices are not adopted or if nitrate contamination in the groundwater increases. Farmers in DWSMAs have three growing seasons or the lag time it takes for water to reach an aquifer system – the longer of the two – during which to voluntarily adopt best management practices.”
The rule states that nitrogen application will not be permitted in the fall or on frozen soil where nitrate level has measured or exceeded 5.4 micrograms per liter at any time during the previous 10 years. (Minn. R. 1573.0030, subp. 1(A)(1) and subp. 3(b).)
Graphic courtesy of MDA
MDA must issue a "water resource protection requirements order" to farmers in a DWSMA with nitrate-nitrogen concentrations of 8.0 mg/L or higher at any time during the previous 10 years. (Minn. R. 1573.0040, subps. 8-9). A water resource protection requirements order would apply to some or all lands in mitigation level 3 DWSMAs (where nitrate-nitrogen concentration has been measured at 8.0 mg/L or higher) and mitigation level 4 DWSMAs (where concentration has measured at 9.0 mg/L or higher).
The rule states that if a groundwater monitoring network is installed or residual soil nitrate testing is conducted in the DWSMA, the order applies to the entire DWSMA. (Minn. R. 1573.0050, subp. 1). The MDA may exclude some areas of a DWSMA from the requirements of the order by determining that an “area is not contributing significantly to the contamination of the well.” (Minn. R. 1573.0050).
An MDA order would require “responsible parties” within a DWSMA to maintain records on nitrogen fertilizer use and comply with fall application and frozen soil application prohibitions. (Minn. R. 1573.0070). The MDA may include other requirements, found at Minn. R. 1573.0070, subps. 1-2, in the order, including that farmers use nitrogen fertilizer best management practices and alternative management tools.
Under specific conditions, including extreme adverse weather, crop failure, or agronomical or technical unsuitability of a required practice (due to soil type, typography, or crop type), landowners are given relief from a water resource protection requirements order. (Minn. R. 1573.0070, subp. 3.)
“Farmers in DWSMAs have three growing seasons or the lag time it takes for water to reach an aquifer system – the longer of the two – during which to voluntarily adopt best management practices.”
The MDA website lists alternative management tools that landowners may substitute in place of a nitrogen fertilizer best management practice required by a water resource protection requirements order. Landowners subject to an order may submit to the MDA alternative protection suggestions. (Minn. R. 1573.0090.) The website also hosts an interactive map displaying current DWSMAs and vulnerable groundwater areas.
“The MDA will form a local advisory team with farmers, agronomists and other community members. This team will be involved in reviewing, considering and advising the MDA on appropriate practices or requirements to reduce nitrate in the DWSMA,” says Gunderson. “The MDA will evaluate best management practices implemented and water quality outcomes, and consider whether regulations are needed. The DWSMA can move to a regulatory level if the BMPs are not adopted or if the nitrate level in the groundwater increases.”
Tracing surface-groundwater connections
Parties throughout the state, including watershed districts, were engaged in the rulemaking process.
“MDA heard from members of the public throughout the state about the length of time it will take to see changes in water quality,” notes Gunderson. “This is because soils and geology around the state are pretty complicated. If every well was built the same, the same pumping rate existed across the state, and aquifers consisted of the same geology across the state, it would be easier to understand and provide better time estimates and greater certainty.”
Graphic courtesy of MPCA
BdSWD Administrator Jamie Beyer notes that it will take time to understand what results to expect, and to see results. “There is a real question about cause and effect in the rule, and the amount of time it is going to take to see changes in groundwater resources as a result,” says Beyer.
“It is an open question right now. It will be important to let this rule take root as the state develops more understanding in the area of groundwater systems," comments Beyer. "As a farmer I am equally concerned about not seeing any measurable benefits as a result of the rule from a regulation standpoint. When policy makers don’t see the outcome they are expecting, that can result in more restrictions on producers.”
“Hydrologic transport time through an aquifer system is kind of an unknown; it could be years,
it could be decades.”
Ongoing research
Researchers are working to establish more certainty around when and where to expect groundwater improvements when practices change on the surface.
Joe Magner, Department of Bioproducts and Biosystems Engineering, UMN
“University of Minnesota researchers are looking at locations in Southeast Minnesota and modelling flow paths to determine where water originates from on the surface in order to track the effects of changes in practices on the surface and understand what the timeline is for seeing changes or improvements in water quality,” says Magner.
“Hydrologic transport time through an aquifer system is kind of an unknown; it could be years, it could be decades.”