Cover Crops: Farming's Strategic Cover

Cover crop choices can benefit soil, wildlife and weed control

Farmers aim to get the most out of their land — but yield is not the only goal. U.S. farmers are increasingly using cover crops as a tool for sustainable management of their fields.

Cover crops also offer farmers additional options in weed control, which mean they might have a growing role in herbicide resistance management.

Researchers agree that cover crops are one of farming's best tools. "This is because they provide many different environmental benefits," explains Dr. Robert Myers, Associate Professor in the Division of Plant Sciences at the University of Missouri. "First, they help to keep the soil in place, so you don't have the erosion. Secondly, they help keep nitrogen and phosphorus in the field, where the crop can use it instead of getting into our water supply."

"Research at the University of Illinois demonstrated that a uniform cover crop of cereal rye (seeded at 40 pounds per acre) before soybeans can provide 98% control of marestail, also known as horseweed," says Chad Watts, Executive Director for the Conservation Technology Information Center (CTIC), located in West Lafayette, Indiana.

The CTIC provides reliable information to support environmentally responsible and economically viable decision making in agriculture. "Cover crops take up space and sunlight and therefore suppress the germination of weeds," Watts continues. "Some of the cover crops also sequester chemicals to the soil, which inhibits the germination or even the growth of these grasses."

Start Small and Simple

West Central, Illinois, farmer Andrew Reuschel uses a variety of cover crops on his farm. He uses cereal rye-based cover crops in front of soybeans and favors annual ryegrass and clover-based cover crops in front of corn. He plants more than 30 species in total and says the exact mix is ever-changing.

"We choose cover crops based on what will work with our timing, our application and our goals," he says. "Cover crops function well for any producer who's willing to think outside the box and make them work, whether they are organic or conventional and no matter what herbicide program they use."

Reuschel offers this advice for farmers considering cover crops: "Start small and simple. Insights gleaned from web research or social media are fine, but be sure to speak with other farmers in your area who use them — that local expertise is key."

If you've planted a cover crop

to protect your fields this winter, chances are it's from one of three categories:

  • Legumes — Clover, peas, vetch

    Legumes live in symbiosis with bacteria, which capture nitrogen and make it available to neighboring crops.

  • Grasses — Cereal rye, wheats, barley, triticale

    Grasses are the most popular cover crops planted in the U.S. Instead of being harvested for grain,they are produced for vegetative cover and removed before they produce seeds.

  • Brassica — Mustards, radishes

    Radishes, in particular, are an increasingly common choice for U.S. farm fields, second only to cereal rye. Other popular choices include turnips, canola and rapeseed.

Are Cover Crops Right for You?

Cover crops help in controlling erosion, help keep fertilizer where you apply it and promote nutrient cycling in your soil. But did you know that they can also help keep weeds in check?

"Like any plants, weed seeds need sunlight and water to grow, and 12-month ground cover and plant residue keep soil shaded so weed seeds don't germinate," says Randy McElroy, Technology Development Representative, Bayer. "Ecosystems respond to management practices. Waterhemp and Palmer amaranth, in particular, do not tolerate competition well; therefore, cover crops can be very effective in controlling them. They also function well when used in tandem with the Roundup Ready® Xtend Crop System."

McElroy says that winter is the perfect time to evaluate cover crops for your operation as part of an 18-month planning cycle. He advises farmers to study cover crops within their latitude (50-75 miles north — south) to see which grow well. And, he shares several helpful resources for additional information:

  • 28th annual National No-Tillage Conference — Jan. 7-10, 2020, St. Louis, Missouri
  • Midwest Cover Crops Council

"Take a field and start practicing with cover crops. You don't have to cover the whole farm overnight," McElroy advises.

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