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Wisconsin Climate Change Task Force looks at Minnesota’s nitrate rule
MN total nitrogen load

WISCONSIN - The Wisconsin process to develop sensitive area revisions to the NR 151 rule to address unsafe levels of nitrate in groundwater continues to progress. At the Technical Advisory Committee’s May 28 meeting, the group heard about the rule recently developed in Minnesota.

Minnesota first adopted their Nitrogen Fertilizer Management Plan (NFMP) in 1990 as an outcome of the 1989 Groundwater Protection Act. It was revised in 2015 after extensive input by an advisory committee of farmers, agronomists, commodity groups and environmental organizations. Six public listening sessions were held as part of a process that lasted five years.

According to Minnesota Department of Agriculture Fertilizer and Pesticide Management employee Larry Gunderson, the goals of the NFMP are to:

• encourage and promote science-based practices to reduce nitrate in groundwater, while maintaining farm profitability

• target areas vulnerable to groundwater contamination

• work with local farmers and agronomists to address local areas with elevated nitrate in groundwater

Gunderson made clear that the emphasis of the program is on prevention and not enforcement.

Township testing

In the aftermath of the adoption of the state’s NFMP, a program of township-based testing was conducted over a seven-year period. This was an effort to establish basic fact finding about the extent and location of problems.

The testing program focused on townships with at least 20 percent row crop production and 30 percent vulnerable geology. In the course of the testing program, over 30,000 wells were tested in 306 townships in 42 counties. This effort was conducted in partnership with counties and Soil and Water Conservation Districts (SWCD).

The initial results in the 2013-2019 testing program were:

• approximately 32,217 wells were sampled in 50 counties

• 9.1 percent (2,925) of those wells had levels of nitrate that were greater than or equal to the 10 milligram-per-liter (mg/L) federal safe drinking water standard
MN N restricted areas
THIS MAP shows the areas of the state under fall restrictions on application of nitrogen fertilizer. The dark areas in the southeast corner of the state are domi-nated by a karst geology overlain by shallow layers of soil, very similar to Southwest Wisconsin.

These first results led to a second round of testing in 2019 where 6,100 wells with nitrate detections were re-sampled. As part of the process, 24 counties have been through Minnesota Department of Agriculture (MDA) initial and final analysis, and 26 counties are still in the initial analysis stage.

All of this work is aided by the underpinning of extensive soil and hydrogeological mapping that has been developed by the Minnesota Geological Survey. With significant public funding, they were able to make a County Geologic Atlas for Water Resource Management. The project had first mapped the geology of the state, and then filled it in with information about the locations of the groundwater aquifers within the geologic formations. The resource is used by the MDA, DNR, and county conservation departments in making land use and water resource management decisions.

Rule development

As a result of this activity, the state was able to move forward with a groundwater protection rule similar to what the State of Wisconsin is now looking to develop.

“The draft rule was released in the summer of 2017 for public comment, and MDA held 17 listening sessions across the state with about 1,500 attendees,” Gunderson explained. “After hearing in-person input as well as 800 written comments, MDA made significant changes, and published the rule for formal comment in 2018.”

The final rule was adopted in June of 2019, and deadlines include:

• Jan. 15, 2020: areas subject to fall nitrogen fertilizer restrictions will be published on the MDA website

• Sept. 1, 2020: fall application restrictions begin

Gunderson explained that the rule applies to the use of nitrogen fertilizer and does not regulate manure. The focus of the rule is protecting groundwater in areas vulnerable to groundwater contamination. There are two distinct parts of the rule:

• fall application restrictions of nitrogen fertilizer in vulnerable areas

• responding to public wells with high nitrate

The responsible party is “the owner, operator, or agent in charge of the cropland.” Enforcement is complaint-driven, with an MDA approach to conduct education and compliance assistance before moving to financial penalties. Penalties are situation-specific, depending on:

• willfulness of violation

• gravity of damages

• past violations

• economic benefit

Fall application

This part of the rule restricts fall applications to frozen soil of nitrogen fertilizer in areas with vulnerable groundwater or in protection areas around public wells with detected high levels of nitrate.

This part of the rule involves an estimated 2.6 million acres, or 12.6 percent of Minnesota’s cropland.

Vulnerable groundwater areas include areas with coarse textured soils, shallow depth of soil to bedrock, or karst geology. Identifying these areas is done at the quarter-section scale.

“If 50 percent or more of a quarter-section is vulnerable, then fall application is not allowed in the entire quarter-section,” Gunderson explained. “The MDA website has a zoomable interactive vulnerable area map.”

The map, and information about the rule and program can be found at:

Exclusions to fall application restrictions are for counties with low-leaching potential based on precipitation and evapotranspiration rates (water evaporating from the soil into the air), and a short planting season, and where less than three percent of the land is used for cropland.

Exceptions are made for specific crops, including winter grains, pasture fertilization, perennial crops, grass seed, cultivated wild rice, and cover crops for reducing the application of soil fumigants in a potato rotation.

Other exceptions involve use of ammoniated polyphosphate or micronutrients, fields with low phosphorous levels, when applying MDA-approved chemical contaminated media, and for demonstration sites of 20 acres or more with MDA approval.

Public wells

The process of implementing the rule to protect public wells focused on developing Drinking Water Supply Management Areas (DWSMA). This is done using the tools developed by the Minnesota Geological Survey to calculate the area in a ‘ten-year time of travel boundary.’

DWSMAs are developed for municipal water systems with a detected level of nitrate that is 5.4 mg/L or higher. Gunderson said that DWSMAs might change year-to-year, based on the variability of various factors such as weather and cropping.

“The goal of this part of the rule is to take action before a public water system exceeds the health standard of 10 mg/L,” Gunderson explained. “Two of the levels in this part of the rule are voluntary, and two are regulatory.”

Gunderson said that landowners affected by the rule are always started out in the program at one of the two voluntary levels. He said that those landowners would progress to regulatory levels only if best management practices (BMP) are not voluntarily adopted or if nitrate contamination increases.

In the program, there are different mitigation levels, but fall restrictions to spreading nitrogen fertilizer apply to all 33 DWSMAs designated into the program. Level One is where nitrate levels are 5.4 to 7.99 mg/L; Level Two is where nitrate levels exceed 8 mg/L or are projected to exceed 10 mg/L in 10 years.

For Level Two, MDA forms a local advisory team composed of local farmers and agronomists, and others, to consider and recommend appropriate practices. Practices need to be adopted on 80 percent of the cropland acres in a DWSMA or the area could move to a regulatory level.

Alternative management

A major goal of the approach taken in the DWSMA process is to promote practices that go beyond the fertilizer BMPs, called Alternative Management Tools (AMT). AMTs can substitute for BMPs. These can include:

• increased low nitrogen vegetative cover – perennial crops, forages, cover crops

• taking targeted land out of agricultural production

• methods to reduce or manage nitrogen precisely

The MDA team uses various models, which Gunderson describes as “robust computer-based models” that simulate the physical and chemical processes that occur in soil and water under agricultural management to determine AMTs.

“The objectives of these models are to predict effects of management decisions on soil, water and nutrient movements, and the impacts of changes to soil, water and nutrient flux on water quality and crop yields,” Gunderson explained. “These studies have been calibrated and validated in multiple regions of the state by the University of Minnesota.”

Within DWSMAs and townships that require a reduction in nitrate in groundwater, the models are used to estimate:

• annual amount of nitrate leaching below the rootzone

• amount of time it takes the water and nitrate to move below the rootzone to the water table or lag time

The team then simulates and quantifies the benefits of different crops and practices, which are recommended to reduce leaching.

“The goal is to provide a tool for producers to evaluate options for reducing nitrate losses that they can consider for their farm,” Gunderson said.

Regulatory levels

There are two regulatory levels of the DWSMA program – Level Three and Level Four. Level Three uses the same water quality criteria as Level Two.

If after three growing seasons or the estimated lag time, whichever is longer, nitrate levels increase or BMPs are not adopted on 80 percent of cropland acres (excluding soybean acres), and after three or more growing seasons residual soil nitrate below the roozone increases, then Level Three sanctions result in an order.

This order may include nitrogen fertilizer BMPs, record keeping, education, information related to nitrogen management, and AMTs if they are funded.

Level Four kicks in when:

• nitrate levels in the public water supply well exceed 9 mg/L for any three samples in the previous 10 years

• after not less than three growing seasons or the estimated lag time, whichever is longer, the nitrate levels continue to increase

• after not less than three growing seasons, the residual soil nitrate below the rootzone increases

Level Four incorporates the water quality standards from Level Three, and includes:

• water resources protection requirements as defined in statute – this must consider economics, practicability, and other factors

• nitrogen fertilizer requirements – cannot restrict the selection of the primary crops or go below the University of Minnesota recommended rates for nitrogen application for crops
MN N Program certification

Certification program

Landowners can choose to enroll in the Minnesota Agricultural Water Quality Certification Program. If accepted, this means that they are in compliance with the rule. The program offers:

• Recognition

• Financial/Technical assistance

• Regulatory certainty

•Branding/Marketing opportunity

• Check-up/Validation for growers

The certification involves whole farm planning for water quality, with risk assessment for every parcel and every crop. It also pairs producers with professionals to develop site-specific solutions for risks to water quality.

Question and answer

Who pays for the water testing?

Funding comes from the Water and Land Legacy Act, which dedicates three-eights of one percent of the Minnesota sales tax (four cents of every $10) to resource conservation projects. The testing is conducted at no expense to the homeowner.

How does Minnesota define shallow bedrock?

Shallow bedrock is defined as less than three feet of soil over bedrock, and this definition is part of the Minnesota Soil Survey.

What about CAFOs with NPDES permits – does the MDA require University of Minnesota recommendations for fertilizer?

NPDES permits are under the supervision of the Minnesota Pollution Control Agency. In their work, they look at total nitrogen rates taking into account last year’s crop and manure application. Our authority relates to regulation of commercial nitrogen fertilizer.

How is the effect of the rule evaluated?

We look at the adoption of BMPs, and cities and health departments monitor water quality in public health supplies. We have established a network of groundwater monitoring wells to measure the effectiveness of adoption of BMPs.

Are farmers receptive to the certification program?

Yes, farmers have been receptive and the program is growing.

How are nitrogen losses related to big rain events?

It’s hard to say, but we try to predict that using modeling.

What lessons can Wisconsin learn from your experience in Minnesota?

Things that helped were more farmer meetings in local areas, and more discussion before moving to regulation. Allowing time for BMP implementation to show an effect slows the process down a little, but is worth it. Another good example for Wisconsin to look at is the program in the State of Nebraska.