Written by Jonathan Eisenthal
Lakefield farmers Jerry and Nancy Ackermann were among the presenters at a gathering in Okabena in mid-November, in which three dozen farmers from Jackson and Nobles county met to compare results, trade experiences and learn ways to improve performance with cover crops.
Jerry and Nancy are members of the Minnesota Corn Growers Association.
The Ackermanns have increased the use of covers between the rows of their corn and soybeans for the past six years. In the 2015 crop year they planted 100 percent of their acres with cover crops.
One key benefit to using cover crops, according to Ackermann, is improving the water-holding capacity of the land. Jerry noted that during the recent post-harvest rains, when the Lakefield area received more than 5 inches of moisture, standing water was seen in many low spots, especially along field edges where grain carts and other equipment had left tracks. In contrast, the edge of a field where Ackermanns planted cover crops, they had just taken off 194 bushels of corn per acre, and they had no standing water at all.
“The covers in that field—they get pushed down a little bit when you come through and pick the corn—but now after the rains they are up and looking greener than ever,” Jerry said.
Covers also contribute to high yields by helping with weed control, according to Ackermann. As they have increased their use of cover crops over the past six years, they have left ‘check strips,’ which have consistently demonstrated how the cover crops work to limit weeds.
Some of the cover crops will die during the coldest months, but the cereal rye among other plants most often survives through the whole winter.
“The more days of the year you can have the roots of living plants in the soil, the better it is for the health of the soil,” Ackermann believes. He has also noticed a solar radiation effect, “where I have covers that have made it through the winter, that soil warms up faster. The plants collect the solar energy.”
Between the warmer soil and its ability to sponge up excess moisture, he has found that they can get rolling with planting a few days earlier than in the past.
As row crop farmers, Ackermanns terminate their cover crops with herbicide right before planting their main crop in the spring. Farmers who raise livestock use cover crops as forage for their animals.
“There’s one farmer I talked with who says he knocked a month off of his feed bill by grazing his animals on the cover crops,” Ackermann said.
They have experimented with different mixtures that have included oats and peas, as well as tillage radish, rapeseed, forage turnips, clovers and ryes.
“I often gain, and I have never lost yield by using a cover crop,” said Jerry Ackermann, describing how he has seen gains as high as 22 bushels per acre, as well as other agronomic benefits.
Water infiltration tests show a higher water-holding capacity of ground that has been cover-cropped, according to Jan Voit, district administrator for the Heron Lake Watershed District.
Ackermanns, along with three other area farmers (Dave Christoffer, Jerry and Terry Perkins and Tim Hansberger) have joined in a three-year “Third Crop Phosphorous Reduction Effort” being conducted the Heron Lake Watershed District. The project will compile information for the 2014, 2015 and 2016 crop years to show the impact of cover-crops on nutrient loading, says Voit.
Between pathways carved by the cover crop root systems, along with the build-up of organic matter and increased biological activity, the Ackermanns saw an infiltration rate of up to 8 inches and hour. Comparable soils with conventionally raised crops were much slower to absorb water—showing a tendency for water to stand on the surface and run off.
The Ackermanns use no-till cultivation for their soybeans, and strip-till for their corn, which also contributes to a high level of surface residue. Spring tillage transects showed the four farms had surface residue coverage ranging from 64 percent to 83 percent. This high percentage of residue protects the soil from both rain- and wind-erosion, according to Voit.
Jerry Ackerman talks more about his use of cover crops in this video:
To learn about research by the Minnesota Corn Growers Association into cover crops, click here.