HARMONY — Farmers in southeast Minnesota have more to worry about than their own bottom lines.
Such concerns were addressed during the “Farming in Karst Country” field day on July 18 at Niagara Cave in Harmony.
Presentations by two local farmers highlighted soil-building practices, water movement and what it's like to farm on karst geology.
According to Land Stewardship Project, who hosted the event, no-till farming, cover crops and rotational grazing can not only improve soil health, but underground streams as well.
According to the Minnesota Pollution Control Agency, the unusual karst geography of southeastern Minnesota has features like caves, hollows and rolling hills that are formed mostly of limestone. This kind of topography makes water in the area more difficult to protect from contaminants.
Olaf Haugen, a dairy farmer on the sloping hills in Canton, talked about how he builds soil and prevents runoff on his farm. He said by focusing growing cover crops, 70 percent of his 160-head herd's feed comes from grazing.
The biggest challenges to operating a dairy farm in karst country are runoff and soil erosion, said Haugen. To combat this, he uses rotational grazing which he says builds a healthier soil that can handle a lot of moisture along with mitigating runoff. Rotational grazing is also good for nutrient distribution, said Haugen.
"With say, set stock grazing, those cattle are not going to distribute nutrients," said Haugen. "They'll go to the same spot for shade every day, and the same spot for water every day."
Cattle is moved every 12 hours in a rotational grazing system, he said, to where depends on the time of year. Haugen's cattle get all of their water when they're in the barn, so he doesn't have to worry about getting it out to them.
"You train the cattle, so they know there's water at the barn and they can come back for it," he said. "It's really not an issue."
Soil, water and farming are intricately connected with karst geology, said Martin Larsen, a fifth-generation Byron farmer and one of the presenters.
“Improving the health of our soils will help maintain the integrity of our agricultural production, groundwater and unique region," said Larsen.
Larsen uses no-till to raise conventional corn, soybeans and cover crops. He works for the Olmsted County Soil and Water Conservation District, as well as the serving president of the Minnesota Caving Club. After recently adding up his trip reports from caving, Larsen discovered that he was underground in Fillmore County for about 500 hours last year.
Through farming crops, working with the county on conservation and seeing what's going on in caves, Larsen has a detailed perspective on the karst move quickly in karst geology and affect aquatic species.
"Anytime that we have runoff from the land surface in karst country, which is quite often now with increased and more intense rainfall, it's likely going to carry into a sinkhole or a direct conduit to groundwater," said Larsen.
He explained the visual representations in karst country, such as blind valleys, where a valley ends abruptly and water cannot flow out it of on the surface. Sinkholes, he said, are closed cavities caused by a collapse of soil above fractured bedrock. There's also features that aren't as visible.
"Just because you don't see it, doesn't mean it's not there," said Larsen of karst characteristics. "And it's really hard for the science community to explain that."
To get an example of what nitrates are doing underground, Larsen collected water samples when he was recently inside the Tyson Spring Cave in Fillmore County. Only one of the four samples he took, which came from underneath an area of permanently seeded grass, was under the standard for nitrate in drinking water set by the U.S. Environmental Protection Agency. And that sample was barely under the standard.
"As a farmer, that really rings to me," said Larsen. "Because even if we are applying nitrogen at the right time and rate, in the right method, it's not good enough to get the water under our crops below the drinking water standard."
He said farmers need to do better than the status quo and better than what's required right now. Knowing that conventional tillage will cause more erosion and runoff, Larsen uses no-till and cover crop techniques.
Through what Larsen calls common sense outreach and education, area farmers are adopting similar practices and seeing great results.
"That's why I do what I do," said Larsen. "I can take this whole picture of farming to geology to soil health, and bring it together so that we can do a better job."