Innovation Grant Spotlight: On-farm research looks for perfect timing of cover crop planting

Written by Jonathan Eisenthal

The 2018 Innovation Grant Program is underway, with 12 farmers receiving grants from Minnesota corn to lead projects focused on nitrogen management. Throughout the summer we will be highlighting ongoing projects focused on how to better manage nitrogen and protect water quality. To learn more about each completed and ongoing project, click here. For more details and to submit a proposal for a 2019 Innovation Grant, click here.

Soil is an irreplaceable resource—it can take millennia of climatic action, weathering of rock and countless generations of vegetation to create a few feet of rich, Upper Midwest topsoil. One of the best ways to hold onto that soil is keeping the ground covered, so wind and rain don’t carry it away.

2018 Minnesota Corn Innovation Grant Program participant Matt Alford is using cover crops to prevent erosion. For his research project, he is setting out to find the best timing for adapting cover crop cultivation to the Northland.

Alford, who farms in Blue Earth, is testing the “interseeding” method—planting cover crops between the rows of the main cash crop during its spring growth. On 20 acres of replicated strips, Alford is planting a diverse cover crop mix at three different timings—V3, V5 and V7. After multiple seasons, Alford will measure which species along with what timing has led to the strongest cover crop growth.

“The goal is to get the cover crops up and get their roots deep enough that they can survive the shade once the corn gets to full canopy,” said Alford. “At that point the covers become dormant until the late season.”

When the corn is fully mature, the canopy opens up and lets in more light, so the covers begin a second stage of growth.

“Once we pick the corn, the cover crops should really take off. They’ll have a few weeks to a month of growth,” Alford said. At that point the covers will have enough biomass to effectively hold on to soil over the cold season.

For the project, Alford is planting ten pounds of annual rye, five pounds of iron clay cow peas, six pounds of buckwheat, a pound of radish, a half-pound of rape seed and a half-pound of turnip. Most of the mixes are cool season species, though cow peas are a warm season legume. Research at South Dakota State University shows that cow peas do very well with corn.

With funding from the Innovation Grant Program, Alford purchased a seed box that mounted on a side-dress bar. Alford farms with his father-in-law, Jim Erdahl, who has for decades side-dressed nitrogen to make sure the crop gets the nutrients when it needs them. When Alford proposed adding a cover crop seeder, so that the two practices could be implemented in a single pass, Erdahl was all for it.

Alford intends to run the experiment for three seasons in a row to ensure reliable results.

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