Nitrogen and water in Minnesota

Recently, Minnesota has made remarkable progress identifying the sources of, and solutions to, excess nitrogen pollution to Minnesotas surface waters. From the states groundbreaking nitrate study, to the states upcoming nutrient reduction strategy and Nitrate Fertilizer Management Plan, Minnesota is quickly becoming ground zero in the debate about reducing farm fertilizer pollution to the nations waters.

Elevated nitrate levels can be harmful to fish and aquatic life, and pollute public and private drinking water wells. In addition, excess nitrate is the primary driver of the oxygen-depleted Dead Zone in the Gulf of Mexico.

There are a number of ongoing efforts to address these problems, including some groundbreaking milestones expected in the next year or so. Heres a quick summary:

Minnesota Nitrate Study

This past summer, the Minnesota Pollution Control released its groundbreaking study: Nitrate in Minnesotas Surface Waters. The study found that more than 70% of the states nitrate pollution is from cropland sources. The lion's share (37%) is from agricultural drain tile systems, while an additional 30% is from nitrate leeching into groundwater and moving underground until it reaches surface streams.

Minnesota Nutrient Reduction Strategy: 45 by 45

The MPCA also recently released its Minnesota Nutrient Reduction Strategy. The document highlights Minnesotas strategy for ultimately achieving long-term nutrient pollution reductions, including a 45% reduction in our share of excess nutrient pollution to the Gulf of Mexico by 2045.

The draft strategy highlights multiple solutions to address both phosphorus and nitrate pollution to the Mississippi River. Dramatic improvements in conservation tillage, nutrient fertilizer management, cover crop acreage, and drainage water management will be required to achieve a 30% reduction in nitrate pollution.

Troublingly, however, the state has not yet identified a scenario where reductions beyond 30% can be achieved using current cropping systems. As a result, meeting our obligation to downstream states and future generations will require widespread conversion from naturally leaky corn and soybeans acreage to more sustainable, ecologically sound crop rotations and perennial crops. These new cropping systems improve soil health, retain water and nutrients, and can dramatically reduce long-term pollution loads to the Mississippi River.

The Minnesota Nutrient Reduction Strategy document is on review for public comment until December 16th of this year. Early next month, FMR members should be on the lookout for an Action Alert on this strategy. This Action Alert will provide members with the opportunity to learn more about this strategy and make specific comments and recommendation to the MPCA on how it can be improved.

Nitrate Standards

Unlike pollutants such as bacteria or sediment, the state of Minnesota does not yet have numeric water quality standards for nitrates. Luckily, the MPCA has committed to developing those standards for the Mississippi River (and other rivers) by January 2015. A numeric nitrate standard for the Mississippi River will be the first of its kind in the nation. Over the coming months, FMR and our partners will continue working with the MPCA and other stakeholders to ensure standards that are scientifically sound, accurate, and adequately protective of aquatic life throughout the Mississippi River.

We applaud the MPCA for this undertaking and will keep FMR members apprised of progress on these standards throughout their development.

Nitrogen Fertilizer Management Plan

Other agencies have been less proactive in addressing nitrate contamination. The Minnesota Department of Agriculture (MDA) first developed its Nitrogen Fertilizer Management Plan in 1990, as a result of the states 1989 Groundwater Protection Act. The plan originally intended to rely on voluntary best management practices (BMPs) to reduce nitrate-nitrogen contamination of the states drinking water wells.

Several decades later, a draft update to the plan shows that while groundwater contamination has increased in most of the state, the MDA will continue to rely on those same voluntary BMPs to reduce contamination of public and private drinking water wells. More worrisome yet, the BMPs offered by the MDA were developed to maximize producer profitability rather than reduce pollution to surface waters or groundwater. Thus, the voluntary solutions offered by the MDA are the very high-intensity fertilization measures that have contributed to excessive nitrate pollution for decades.

While the Groundwater Protection Act allows the state to develop tough new rules for nitrate fertilizer management in areas where voluntary BMPs have been ineffective (which is most of the state), the MDA in its draft plan has chosen not to pursue new rules despite significant risks to public health.

FMR recently submitted comments on the MDAs draft Nitrogen Fertilizer Management Plan, and looks forward to working with the agency on much-needed revisions in the coming weeks.

Legacy Nitrate

Somewhat surprisingly, recent research shows that nitrogen fertilizer can remain in soils and leech towards groundwater for decades. Over a 30-year study, scientists in France and at the University of Calgary measured the amount of nitrate fertilizer applied in 1982 that was taken up by sugar beet and winter wheat crops over subsequent years.

While 61%-65% of the fertilizer applied in 1982 was taken up by the sugar beet and wheat plants over the 30-year study, more than a third of the fertilizer remained in the soil after three years, and 12%-15% lingered in the soils after 30 years.

Approximately 8%-12% of the fertilizer applied in 1982 had leaked in the form of nitrate toward groundwater over a 30-year period, and according to the authors, will continue to leak at low rates for at least another five decades.

This research reaffirms the vital importance of addressing excess agricultural nitrate applications now, as the consequences of excessive fertilizer application can be seen for decades to come.

Conclusions & Next Steps

Given the extensive new research on nitrate sources to Minnesota surface waters and groundwater, its clear that our state is quickly becoming a key proving ground in the effort to prevent excessive nitrate contamination of our waters.

FMR and our partners will continue our efforts to work with state agencies, local governments, conservation and recreation groups, and conservation-oriented farm organizations to advocate for meaningful reforms to state laws, strategies, water quality rules, and clean-up plans. Meanwhile, Mississippi Messages readers should be on the lookout for an Action Alert on the Nutrient Reduction Strategy in early December.

We know that nitrate contamination problems didnt happen overnight, and solutions will take time. However, by working together and speaking up for our Mississippi River, we can all help do our part to protect and restore this wonderful resource for our friends downstream, and for generations to come.

For more information about our water quality work, visit us online or contact FMRs Trevor Russell at (651) 222-2193 x18 or trussell@fmr.org.