Written by Jonathan Eisenthal
John and Jewell Peterson, and their kids Nate, Nic and Natasha, all enthusiastically joined the Minnesota Discovery Farms program six years ago. The family produces corn and soybeans in North Branch and for decades they have worked hard to conserve soil and prevent nutrients from running into the St. Croix River watershed.
“The data shows we are doing a pretty good job with the no-till,” says John Peterson. “It’s helping save soil and nutrients. The data also taught us we do need to pay attention to weather—if a rain event comes too soon after a nitrogen application, you can lose quite a bit of your nitrogen.”
They were recently honored for taking part in Discovery Farms, which is a farmer-supported effort to develop scientific data about the environmental impacts of various modern agricultural practices, and to sort out the most effective conservation techniques.
Petersons have no-tilled corn and soybeans in a fifty-fifty rotation since the 1990s. The low volume of soil loss and the land’s high water-holding capacity testify to the effectiveness of reducing tillage intensity.
“The soil gets better every year,” says John Peterson. “It’s more mellow, yet has better structure. It holds up better when it’s wet. It absorbs more moisture quicker, lets it run down into the ground.”
John describes how he was able to combine his beans last fall when everyone else was kept out of the fields by the wet ground. Equipment was making knee-deep ruts in the neighbor’s field, where, just across the fence line, in Peterson’s field, there wasn’t even any sign of moisture on the surface.
But that doesn’t mean moisture was lacking when the plants needed it in the growing season. Peterson says no-tilling can make planting trickier in northern zone locales like his farm, but certain techniques make it work. For instance, he doesn’t chop his corn stalks but instead leaves them standing tall and this allows the sun to penetrate between the rows and warm the soil. Only after planting his soybeans does he come along with a roller and push down the stalks so the residue creates a blanket at the surface that holds in moisture and adds nutrients and organic matter to the soil as it decomposes.
One area for improvement pointed out by the data was phosphorous loss. In response, Petersons have gone to a modified strip till for their corn, so that they can band the phosphorous and potassium at a six inch depth directly under where the seed will be planted. RTK global positioning makes for accurate seed placement—this is technology now widely used by row crop farmers to limit nutrient losses and make sure their crops get all the food they need.
Even with the strip, tillage is extremely limited, but Peterson assures that the soil structure that develops with lower tillage intensity makes a great seedbed.
“Your roots can grow just as freely as in tilled soil,” John says. “What the roots are doing is they are growing down old root holes, worm holes, cracks in the ground from frost. When the water comes it goes down all those holes and root veins and the nutrients come down those same holes and root veins. It’s a very economical system, when it’s working. When you think about all the little things like that, it just makes so much sense.”
Minnesota Discovery Farms is administered by the farmer-supported Minnesota Agricultural Water Resources Center, which partners with Minnesota Department of Agriculture and local Soil & Water Conservation Districts, in order to collect and analyze water samples and develop long term data bases that will help guide farmers in their management and stewardship decisions.