Cover Crop Decisions: Thorough Planning Increases The Odds For Success

DETERMINE YOUR OBJECTIVE

“Don’t plant a cover crop because you feel pressure from neighbors or speakers at meetings,” Ferrie advises. “Decide what you what to accomplish.”

Financial incentives, such as subsidies or the opportunity to sell carbon credits, are valid reasons. So is obtaining an extra grazing crop or suppressing weeds in hopes of eliminating a fall burndown application.

But your motive might be simple stewardship — reducing soil erosion or improving soil health. In that case, you might be less concerned with obtaining an actual dollar return on your cover crop investment.

Make sure everyone involved understands and supports your goal. Then, plan your strategy.

If an incentive program is involved, check the requirements. Can you plant a cover that winterkills, or will you have to kill it next spring? Must you let the cover crops grow until a specific date?

Start small. “The learning curve is steep,” Ferrie says. “Learn how your cover crop performs in your natural and physical environments. Use this knowledge next year.”

Choose a cover that will achieve your goal and fit your planting window. As you narrow your choices, consider the recommended planting date for each one.

Online resources such as the Midwest Cover Crop Council’s Cover Crop Decision Tool and Cornell University’s Winter Cover Crop Planting Scheduler can help you find covers that fit your planting window.

“Because many covers have to be planted by a certain time, a summer crop such as wheat opens up many options,” Ferrie says. “In a corn/soybean rotation, as you move north, it becomes harder to establish cover crops that need to be planted before the cash crop is harvested, such as clovers and vetch. Aerial or high-clearance seeding might help, but success will depend on how much rain falls after seeding.

“In our central Illinois plots, we have had less than 50% success when we used aerial or high-clearance application to plant species that required seeding between Aug. 1 and Sept. 1. However, aerial and high-clearance seeding works for covers that have a longer establishment window, such as oats, triticale, cereal rye and radishes.”

Seed for cover crop species that can be planted after a cash crop harvest, such as triticale, wheat and cereal rye, can be applied with fall fertilizer. “In our trials, drilling the cover crop seed or lightly incorporating with vertical tillage has been most successful,” Ferrie says. “This requires having your seeding team running alongside your harvest team.”

MANAGE CORN’S CHALLENGES

“Planting a cover crop ahead of soybeans is relatively easy,” Ferrie says. “You have more options, such as wheat, cereal rye and triticale.

“It’s tougher ahead of corn. In our studies, an oats/radish mixture has worked best. Neither species overwinters, so we don’t have to kill them. If you must grow an overwintering cover ahead of corn, include a grass such as wheat, cereal rye or triticale in a mixture with radishes, mustards or clovers. If the broadleaf species don’t survive, at least you’ll have the grass. If it doesn’t germinate in the fall, it will germinate next spring.”  

HERE ARE SOME WAYS TO HELP CORN COPE WITH COVER CROP RESIDUE:

With heavy residue cover, the carbon penalty can last for months. Applying starter and extra nitrogen with your planter can help plants deal with that, as well as the cool conditions created by surface cover and the allelopathic effect of some grasses.

Plan to manage insects, slugs and rodents, which thrive in heavy residue. A T-band of insecticide can help with insects such as cutworms.

Creating an ideal seedbed is tougher following a cover crop. Planter attachments that fit your soil and residue conditions can help. Fall strip-till might be the best option (see chart on page 38).

Killing the cover early (in light of program rules) reduces — but does not eliminate — the carbon penalty, rodent problems and allelopathy issues.