The Minnesota Pollution Control Agency earlier this summer announced it was postponing its proposal to adopt a new nitrate aquatic life water quality standard.
MPCA, which has called development of a Class 2 aquatic life standard for nitrate “a longtime priority,” now plans to follow a more collaborative approach to reducing nitrogen in surface waters.
The announcement calls for developing a detailed Wastewater Nitrogen Reduction Strategy with targeted actions to reduce nitrogen coming from wastewater treatment plants, along with completion of a 10-year revision of the agency’s Nutrient Reduction Strategy to address nonpoint and point sources. Agricultural runoff falls into the nonpoint category.
Published in 2014, the Minnesota Nutrient Reduction Strategy largely parallels plans to address hypoxia in the northern Gulf of Mexico for the Mississippi River Basin, calling for a 45% reduction in both phosphorus and nitrogen from average conditions during 1980-96. For nitrogen, the goal is to reach this 45% reduction by 2040, with a milestone goal of a 20% reduction by 2025, which will soon be upon us.
Other basins within the state have been assigned smaller nitrogen reduction goals.
The postponement includes agency strategies and actions to enhance programs that actively address the largest sources of nitrogen to surface and groundwaters, and to enhance wastewater treatment for nitrogen. MPCA plans to coordinate with stakeholders and provide opportunities for review.
Proposed actions to reduce nitrogen loss from farm fields include:
- improving fertilizer use efficiency
- planting cover crops
- planting perennial crops
- treating drainage water
- establishing buffers
For purposes of the Nutrient Reduction Strategy, 100-foot buffers (double the current buffer requirement for public waters) are suggested.
The agency published a technical report in 2010, which included draft nitrate standards for aquatic life that are much more stringent than the human health standard for drinking water. This proposal elicited great concern from agricultural organizations and municipalities.
At that time, the U.S. Environmental Protection Agency announced plans to pursue supplemental nitrate aquatic life tests. Now that those studies are largely wrapped up, MPCA intends to begin technical review of this new information and update the 2010 technical paper.
So while you work to incorporate the latest soil fertility science, such as new nitrogen efficiency enhancers (some that work, some that don’t), and prepare for evolving global markets for crops and fertilizer, you can add pressures related to new water standards to the list.
Formo is executive director of the Minnesota Agricultural Water Resource Center.