Innovation Grant Spotlight: Finding the optimal cover crop planting window

Written by Jonathan Eisenthal

Looking from the drone’s eye view, the difference cover crops have made in the fertility at Matt Alford’s farm is evident.

“You can see there is a green, defined square where we inter-seeded,” Alford said, “The area where we inter-seeded that first year, the soybeans the following year were five bushels better than anywhere else.”

Farming in Blue Earth, Alford is in the second year of his project studying the impact of cover crops on corn and soybean production. The project is funded through the Minnesota Corn Innovation Grant Program, which promotes farmer-led research like Alford’s aimed at preventing nitrogen and phosphorus loss on the farm.  

When he first started researching cover crops, Alford became focused on finding the optimal planting window to get the cover crop seed into the ground early enough for some growth before it is shaded out by the corn canopy. When the corn matures in September and the canopy thins, the early-planted cover crop puts on a growth spurt, then really takes off when it receives direct sunlight after harvest.  

Preliminary results show optimal planting timing is when he would normally be topping off the nitrogen with a side-dressing pass. With the corn is around a foot to 18 inches tall, he planted his blend of annual rye grass and buckwheat, along with smaller amounts of turnip and rapeseed. In corn-on-corn rotations, he plants a light rate of annual rye grass, with hairy vetch, red clover and turnip.

With funds through the Innovation Grant Program, Alford was able to retrofit his side-dress nitrogen machine with a seed delivery box, with outlets and fans to blow the seed down into the delivery units. The action of the applicator mixes fertilizer and cover crop seed together and lightly incorporates it in the soil.

Once he was able to nail down the right rate of pre-emergent, Alford has seen savings in his herbicide cost because the cover crop has essentially eliminated the need for a post-emergence herbicide application. Alford has saved $15 dollars an acre through the combination of increased yield and reduction in his herbicide application.

The results were eye-opening to Alford, as well as to his peers. Alford presented his findings through the Innovation Grant Program at this year’s National Strip-Tillage Conference in Illinois, where he was applauded.

Interested in taking part in the 2020 Innovation Grant Program? In addition to innovative solutions to prevent nitrogen and phosphorous loss, the program now also seeks innovative ideas in nutrient use efficiency, tillage, economics and management, and production practices that enhance water quality. Proposals are being accepted until Dec. 31. Click here to apply.

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