State proposes new fertilizer rules to protect groundwater

Runoff ditch
Researchers will be able to tell Kent Bartholomay if fertilizer he applies to his fields is flowing down this ditch with runoff water. Fertilizer runoff can degrade water quality in rivers and means lost revenue for the farmer.
Dan Gunderson/MPR News 2009

Aiming to protect groundwater, the Minnesota Department of Agriculture is proposing its most wide-ranging regulation of farm fertilizer use in the state.

For the first time, the agency wants to restrict the fall application of nitrogen.

After the fall harvest and before the ground freezes, farmers apply fertilizer for next year's crop. But doing so makes the fertilizer susceptible to several problems before it's absorbed by crops the next spring.

With heavy rains and snow melt, fertilizer can leach into groundwater or run off into streams and lakes. It can also vaporize into the air.

As part of an ongoing process to draft new standards for managing nitrogen fertilizer in the state, agriculture department officials say they will begin developing new rules. The main target will be farm fields where there's a high potential the nitrogen could reach groundwater, where it poses a health risk to pregnant women and young children.

"In those areas we would restrict the fall application of nitrogen fertilizer, and other non-advised practices in terms of the use of fertilizer," Assistant Agriculture Commissioner Matthew Wohlman said.

Wohlman said the agency has identified about 280 townships across Minnesota where nitrogen poses a high risk problem for ground aquifers. He said the agency has a variety of penalties available to enforce the restrictions, including criminal sanctions.

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