Starting this week, farmers in parts of Minnesota, including in Morrison County, will face new restrictions on how they apply nitrogen fertilizer.
The regulations are aimed at reducing nitrate contamination in the state's groundwater. But whether they'll have a real impact on a growing health and environmental problem is still up for debate.
In a testing program a few years ago, more than half of the wells tested in Agram Township had a level of nitrate higher than what the federal government considers safe for drinking water.
Above that limit, nitrate poses a health risk to humans, especially infants. Consuming too much nitrate can cause a potentially serious or even fatal condition known as blue baby syndrome.
Nitrate contamination can come from different sources, including septic systems and urban drainage. But in Minnesota, the biggest source is the fertilizer and animal manure commonly applied to farm fields.
It took several years for the Minnesota Department of Agriculture to develop what’s known as the Groundwater Protection Rule, to tackle the problem. It took effect in June, and the restrictions that govern when farmers in specific areas can apply fertilizer begin Tuesday.
Starting this week, farmers won't be allowed to apply nitrogen fertilizer in the fall or on frozen ground, in parts of Minnesota where the groundwater is vulnerable to contamination. The rule applies to about 12 percent of the state’s cropland, mainly in the central and southeastern parts of the state.
In those areas with coarse soil or karst bedrock, nitrogen applied in the fall is more likely to run off or leach into the groundwater before it can be used by crops planted in the spring.
But that first part of the rule may not have a major impact. Many farmers in those regions already avoid fertilizing in the fall, because it wastes costly fertilizer.
“Most farmers have already adopted that, in some cases as much as 20 and 30 years ago,” said Warren Formo, executive director of the Minnesota Agricultural Water Resource Center.
Morrison County’s Soil and Water Conservation District manager Shannon Wettstein doesn’t expect that restriction to change much for farmers in her region.
“Around here, folks understand if they're going to apply in the fall, because of sandy soils, it drops out so quickly that that is lost revenue for them,” she said. “They're not going to see that come back around in yield on their crops.”
Local advisory groups made of farmers, agronomists and community members will meet to discuss local water conditions and decide on the best practices for their areas, Formo said.
“I think that just the having of that discussion will have an impact because farmers can learn more about groundwater and how it flows in their area,” he said. “Then they hopefully will be provided with information by the Department of Agriculture to start connecting that to their practices, and which practices are making the biggest difference.”