Need to lose 10-34 lbs?

Nitrogen is a critical input for agricultural productivity and a potent pollutant in the water environment. Significant private investment is made in the former, but significant state investment is required to address the environmental degradation from excess nitrogen in drinking water.

Fields in the Root River watershed that have been intensively monitored by the Minnesota Department of Agriculture (MDA) for four years have been found to lose from 10 lbs. to more than of 34 lbs. of nitrogen per acre. Who loses when fertilizer is lost? All of us: the farm family; neighbors hoping to swim or fish in local lakes that are so fertile that they grow an excess of algae and plants, smothering the aquatic life; small-town residents that have to shoulder the tax burden to drill a new well or build a new water treatment plant so they can drink their groundwater; and taxpayers who fund the monitoring and cleanup of the state’s increasingly polluted waters.

As the lead state agency for fertilizer management, the MDA must provide guidance so that fertilizers do not degrade our water. Their current draft rule is far from ideal and is only working on the edges, on small-scale changes that will not reverse the trend of increasing nitrogen contamination in groundwater.

A future BMP? Corn planted in kura, a clover-like perennial. Rosemount Research and Outreach Center, University of Minnesota, 2016

The draft rule offers farmers in the most vulnerable areas the opportunity to voluntarily implement best management practices (BMPs). However, if farmers choose not to do so, they face no real consequences.

Recommended BMPs haven’t been demonstrated to reduce groundwater pollution, but instead they benefit crops. And if a more effective practice becomes available, a farmer won’t be required to adopt it. Since farmers are already doing most of what is being proposed in this rule, overall trends in nitrogen in the groundwater won’t be reversed.

The MDA is only testing groundwater that they have judged to be at risk and water that is already contaminated. Other areas do not have a way to get tested.

What should a proactive rule intended to protect groundwater and reverse trends contain?

Ideally, a rule 28 years in the making would require increased efficiency of nitrogen use. This would save the producer and the state money while reducing loss of nitrogen to the environment.

The rule should establish measurable goals and limits for nitrogen loss, provide for ongoing testing of affected groundwater until trends reverse, and notify affected well owners who did not participate in the program.

Only after widespread excessive application is controlled should further reductions be made by targeting vulnerable areas in the way proposed in the current draft. This could include low-cost but effective solutions for producers, such as cover crops. But those efforts alone are unlikely to reverse the current trends.

The MDA is accepting comments on the Nitrogen Fertilizer Rule through Friday, August 25. Learn more here and add your voice to the process.

— Carrie Jennings, research and policy director