Special field day highlights benefits of Kernza on soil health

The field day was well attended, and attendees had numerous questions for the presenters. GRETCHEN MENSINK LOVEJOY/CHATFIELD NEWS

Martin Larsen, of the Olmsted County SWCD, speaks about soil health during the Kernza field day sponsored by the SWCD in Chatfield. GRETCHEN MENSINK LOVEJOY/CHATFIELD NEWS
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August 22: Field Day.

Purpose: Amber waves of grain conquering erosion, carbon dioxide.

The Olmsted County Soil and Water Conservation District (SWCD) presented a field day at the privately-owned acreage along Wisdom Lane where the city of Chatfield planted Kernza, or intermediate wheatgrass developed by the University of Minnesota to help hold topsoil in place and capture carbon dioxide from the atmosphere to reduce greenhouse gases causing climate change.

Farmer Martin Larsen, of the SWCD, said, “This opened up the opportunity for cover crops on my farm, and there’s been pretty stark changes. I’m the fifth generation on our 700-acre farm, and our acreage is 100 percent no-till and cover crop, and next door, with only two inches of rain, you can see the signs of runoff, soil loss, and phosphorus coming in. Keeping the soil armored and increasing plant diversity with a continuous root in the ground and integrating livestock into the plan…it’s a changing philosophy.”

As a farmer, Larsen said he was locked into the idea that soil was a factory and that one should put in commercial fertilizers to get a product out.

“That’s not what Mother Nature intended,” he said. “When you look at the soil as a whole, you look at the complex system it is. The two-crop system leaves barren soil until you plant again in the spring, and vegetation growth drops off and leaves a lot of time before planting, and there’s not much growth, nutrient uptake and carbon dioxide sequestering.”

Larsen told how his farm now has winter rye planted to slow erosion and how he “inter-seeds” his fields to plant two crops at the same time — the annual crops with perennial crops in between the rows — so that there is “minimal disturbance” of the ground, a goal of no-till farming because each time a field is plowed or worked, its soil structure is changed.

“You can drastically change the water leaving your farm,” Larsen said. “In southeastern Minnesota, it’s groundwater, and you’re dealing with soil loss, nitrates and also the quantity of water. There are differences between no-till and tilled land.”

Larsen continued, “Does anyone here know the thickness of a dime?”

An attendee answered that question with the measurement he sought, and he posited, “The thickness of a dime in soil loss is 5 tons. Do you think you’ll go to Menards and get that? You have to keep it on there.”

In his role as an Olmsted SWCD employee, Larsen related that the SWCD manages a 55-acre demonstration farm that lends itself to experimentation and demonstrations of prudent and imprudent soil practices.

“We have six plots we’ve replicated…and we have 12 lysimeters (instruments that measure soil) there to sample groundwater and nitrates within each of those six lots, and there’s a little different management for each,” he said. “Last year, we took 225 samples extracted from the lysimeters, samples from underneath soybean crops. There’s a difference where the residue is from where the cover crops were. Once you add the cover crops, you see that the drinking water above is improved.”

He then gave a demonstration using two cylinders filled with soil, one from a traditionally worked field and the other from a no-till field. He had an assistant pour red water in one and blue in the other, showing the attendees how the blue water filtered down through the no-till soil and the red water sat atop the traditionally-worked soil, leaving it slow to absorb and prone to washing the topsoil away.

He pointed out that organic matter left in the no-till soil made room for the water to filter through and that the continuous upheaval in tilled fields upsets the balance of the pores in the ground.

“The principles are the same — you need the structure and organic matter in the soil,” Larsen said. “It allows water to move around and leaves open space in the soil. There’s better nutrient uptake and water infiltration.”

Larsen then used the example of the attendees standing together in a crescent around him as he spoke. “Look at you as a crowd. You have your comfort space and I could walk between you right now, but if I took away your comfort space, I wouldn’t be able to walk between you. The macro-pores take up a lot of the water in the soil…those are made by earthworms and roots. The macro-pores get reset every time you do tillage. It destroys the structure of the pores, releases carbon and lowers organic matter. When you convert to no-till, there is some crop yield drag because you have to allow the cover crops to catch up. But the water capacity is greater when there’s bigger roots. Inherently, corn and soybeans are leaky crops. Kernza has a fibrous root system and does a better job of reducing nitrates and carbon dioxide. In more ways than one, we’re over-relying on two crops, and when there are years like this that start off very wet and we’re seeing a dry period right now, the organic matter is a saving grace.”

Larsen was the second speaker in a series of field day presenters who outlined what Kernza can do for crop farming and the local drinking water service management area (DWSMA) wellhead protection plan. The morning’s speakers also included Scott Hanson of the Minnesota Rural Water Association (MRWA) and Greg Klinger of the University of Minnesota Extension presenting on the results of three years of on-farm nitrogen studies in southeastern Minnesota. Jake Jungers of the Forever Green Initiative spoke about how Kernza has been chosen as a profitable crop to protect source water. Erin Meier of Green Land, Blue Waters shared information on “Emerging Markets for Kernza Perennial Grain,” with a short presentation by SWCD staff on a Kernza soil pit and sampling of food and beer produced from Kernza grain.

Chatfield planted two plots of Kernza — one on the private property near Wisdom Lane and another on a city-owned acreage just off County Road 10 east of Chatfield — as part of a University of Minnesota and MRWA pilot program for wellhead protection and cover crop promotion.