Many of the agricultural areas of Minnesota have surface and groundwater nitrate-nitrogen concentrations in excess of the federal drinking water standard. Several communities have installed nitrate-removal systems for municipal water supplies.

The Minnesota Pollution Control Agency has just finished its report “Swimmable, fishable, fixable? What we have learned about Minnesota waters,” which cites pollution of waters in the southern, agricultural third of the state and concludes: “Implementing the strategies identified so far will take 20 or 30 years — or more — with interim milestones to measure and motivate progress.” And the Minnesota Department of Agriculture is adopting regulations to restrict fall application of nitrogen fertilizer and applications to frozen ground in areas susceptible to nitrates in groundwater.

Gov. Mark Dayton has actively promoted the use of buffer strips to clean up Minnesota streams, rivers and lakes, including in his recent State of the State address. His proposal seeks a $20 million appropriation. Farmers are complaining about the strips taking cropland out of production. None of the parties to this debate, however, is preparing for a potentially much larger intrusion into the state regulatory framework, Minnesota farming and water-quality practices, thanks to the federal courts.

Nitrogen is 80 percent of the air we breathe and also a primary nutrient for plant growth and a key fertilizer ingredient. Recent federal court cases in Washington state and Iowa could soon pave the way for lawsuits that would significantly impact farming and water-quality practices here in Minnesota.

The federal court in Washington ruled that a dairy farm’s application of manure to soil violated federal pollution laws, notwithstanding the farm’s resolution of EPA enforcement, by discarding a “solid waste” as garbage. The manure was applied at times and at rates that resulted in nitrogen nitrates migrating below the plant root zone, meaning that they could not be used by crops as fertilizer and that the farmer was liable.

Meanwhile, in Iowa, notwithstanding state regulations, the Des Moines Water Works has filed federal court actions against drainage districts for violating the federal Clean Water Act for not obtaining federal environmental permits for ditches and tiles as point sources of nitrate pollution. The suit argues that drainage accelerates and aggregates nitrate pollution in subsurface groundwater and that the agricultural runoff exemption for those permits does not apply. The Water Works seeks a federal order directing drainage districts to stop the excessive nitrate concentrations in farm drainage waters and to pay the costs of treating the water.

Today’s challenge with animal waste that is produced around the clock is liability for nitrogen in manure applied to cropland that crops cannot use. While municipalities confront greater treatment costs from higher nitrate levels in the water supply, crop farmers cannot obtain maximum yields if nitrogen in fertilizer is restricted below the amount needed by crops to achieve those yields. In Minnesota, maximum yields for corn can be 40 percent to 50 percent greater than state average yields. The fight will be over restricting a farmer’s right to achieve maximum yields vs. excess nitrates. It’s likely only a question of time before the war on nitrates comes to Minnesota and federal court orders and nitrate regulations fracture communities into winners and losers.

There is a better way that can be implemented in five to 10 years. Minnesota has a history of solving major environmental problems. When the Twin Cities region experienced an air-quality problem in the 1970s and 1980s, a 10 percent ethanol requirement was coupled with a significant producer credit to ethanol production facilities that was funded by the gasoline tax on the ethanol portion of gasoline. Environmentalists and farmers both supported the results.

A solution to the problem is for the state to lead a development effort to create a market for animal byproducts (the new name for “manure”) to be used as a feedstock for processing into useful products and energy. In California, Calgren Renewable Fuels, which received a substantial state grant, recently opened a plant to use dairy manure as a feedstock to produce more than 50 million gallons of ethanol per year. Companies in and outside of Minnesota are using animal byproducts for anaerobic digesters to produce renewable natural gas that is eligible for federal credits, and other companies are producing chemicals and materials for commercial use. At the same time, the state could support technology that would apply crop fertilizer more efficiently and also use nitrate-laden waters for beneficial purposes. The city of Houston provided a good example of this approach, when it recently completed test algae tanks that removed 90 percent of the nitrates from its wastewater. Scientists at Western Michigan University are developing three-dimensional, printable nutrient “scrubbers” for farm-size nutrient removal by algae. In both cases, the algae can then be used to produce biofuels and other products. A Western Michigan professor is developing a 3D-printable substrate for farm-scale systems to stimulate algae and bacteria growth to remove nitrogen and nutrients from water runoff and recycle it as an organic fertilizer. Australian researchers are working with three types of microalgae that grow on hog waste manure and remove nitrogen and other nutrients. They believe the microalgae can be incorporated in feed for the hogs.

Nitrogen application is more of an art than a science. Farmers don’t intend to waste expensive fertilizers; rather, they apply it in order to sustain crop yields. Regulations and court orders restricting nitrogen won’t change plant uptake and climate variables, but restricted nitrogen can significantly reduce crop yields. The state should take a bold step and create a financial credit for projects using animal byproducts as a feedstock and projects removing nitrates from water supplies. A new industry can stop the coming war on nitrates in its tracks while boosting Minnesota’s economy.


Mark J. Hanson is an attorney with the law firm Stoel Rives LLP.