Updated: 4 p.m. | Posted: 10:22 a.m.
Gov. Mark Dayton unveiled a revised measure Tuesday to reduce elevated nitrate levels in water supplies that includes restrictions on the application of farm fertilizers in the fall, his administration's latest move as it seeks to make protecting water a hallmark of his final term.
The rule would create a system of voluntary and mandatory mitigation practices in vulnerable areas with porous soils, and in locations that have high nitrate levels in public water supplies. Dayton and Agriculture Commissioner Dave Frederickson announced the update after holding 17 public meetings attended by over 1,500 farmers, landowners and other Minnesotans, and receiving more than 800 written comments on an initial draft that was released last summer.
"One of the ways in which we're protecting water quality in Minnesota is by asking farmers to look twice at their practice of spreading nitrate ... on their land in the fall," Dayton said at a news conference.
The Minnesota Pollution Control Agency said most nitrates entering groundwater come from human-caused sources including manure and other fertilizers. Excessive levels can be toxic, particularly to bottle-fed babies under six months old, because they can affect how blood carries oxygen. They can cause a life-threatening disorder known as blue baby syndrome. There's also been some research associating high nitrate levels in drinking water with elevated risks for certain cancers. High levels can harm fish and other aquatic life.
Several communities and private well owners in Minnesota and other farm states have had to install expensive treatment systems to bring nitrates down to safe levels. The Des Moines Water Works in Iowa even sued, unsuccessfully, to recover some of the millions of dollars it has spent to remove pollutants running off from farms upstream. Reducing nitrate levels is one goal of Dayton's signature environmental accomplishment so far, his law requiring farmers to play buffer strips between their fields and waterways to filter out pollutants.
But Minnesota's nitrate rule has been a tough sell to farmers. It's common and convenient for farmers to apply chemical fertilizers and manure in the fall after harvesting their crops, instead of waiting for spring when there's often limited time between when the soil dries out and planting deadlines. Doing so, however, raises the risks of nitrates seeping into groundwater and running off into streams and lakes when the snow melts.
The subject was so sensitive in heavily agricultural Brown County that the county board last December rejected the Minnesota Department of Agriculture's officer of free well tests for nitrates. Local farm groups objected, and commissioners expressed worry that the state would use the data to regulate how farmers use fertilizers.
Steve Suppan, senior policy analyst at the Minneapolis-based Institute for Agriculture and Trade Policy, which promotes sustainability, said the fertilizer industry is largely self-regulated and that approach hasn't been working well to cut farm pollution. But he said Minnesota's rule could become a good model for other states, particularly the upper Midwest.
GOP Sen. Mark Johnson of East Grand Forks, who has introduced a bill to require legislative approval for the rule, called the new version "a step in the right direction." He said it expands the areas where the fall fertilizer restriction wouldn't apply because of lower risks. But he said it's still "about 10 years behind schedule" because computerized modern farm machinery allows farmers to apply fertilizer only where it's needed.
"This rule maybe will help protect some areas but right now I think it's really behind the curve," he said.
Frederickson said the proposal focuses largely on the Mississippi River watershed, which has porous geology that lets nitrates more easily leach through to the groundwater. Though he and Dayton hope the change improves water quality in local wells, Frederickson said the origin of the Mississippi River in Minnesota makes it even more important to reduce nitrates. High nitrate levels in the Mississippi are blamed for fueling the growth of algae that deplete dissolved oxygen and cause the annual "dead zone" in the Gulf of Mexico.
"We literally have a moral obligation to do what's right," he said.
A 30-day public comment period will begin in mid-May, and the Minnesota Department of Agriculture will hold more public hearings sometime this summer. The department expects to submit the final revised version in December.