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How to get the most out of cover crops

In-field assessments allow farmers to evaluate whether their practices paid off.

Ben Potter, Senior editor

May 17, 2023

4 Min Read
Jim Isermann in a field of cereal rye
EVALUATING SUCCESS: Jim Isermann inspects a field of cereal rye for biomass, potential beneficials such as earthworms, potential pests such as slugs and more at a recent field day in Champaign Co., Ill.Ben Potter

Cover crops have long been seen as a conservation multitool that can reduce erosion, break up soil compaction, suppress weeds, increase organic matter and more. But curiously, it’s a largely agreed-upon best practice that is nonetheless rarely practiced. Recent research from the University of Illinois suggested that adoption was only at 7.2% through 2021, based on remote sensing using satellite imagery.

“At the moment, cover cropping remains something for innovators and early adopters; it hasn’t taken hold as a common practice,” according to Jonathan Coppess, associate professor with the U of I Department of Agricultural and Consumer Economics. “A big part of the problem is that adding cover crops to the rotation is a systems change for the farmer and the fields. It adds cost, risk, and management challenges.”

Joe Rothermel, a fifth-generation Illinois farmer, is in the minority of operations that have tackled those challenges in hopes to improve his soil health. Rothermel admits it hasn’t always been a picture-perfect experience.

“My experiences have varied from complete failure to getting what we wanted – it has been all over the board,” he says.

The No. 1 thing Rothermel has learned over the years? “Never go out without doing your homework first,” he offers.

To that end, Rothermel joined the inaugural Advanced Soil Health Training cohort several years ago. This 18-month training course, now led by the Illinois Sustainable Ag Partnership, which is comprised of 15 organizations that are promoting ways to maximize the efficacy and profitability of cover crops and other conservation-minded farming practices.

The current 2022/23 cohort is around halfway through its cycle and met up in late April to walk through various cover crop issues including conducting a proper stand count, scouting for pests, talking through proper termination practices and more.

“Know what you’re actually trying to change,” offers ISAP soil health specialist Jim Isermann. “Know your goals before you get started. For example, how much biomass do you want? And what are you planting the following season?”

As one example, cereal rye is a popular cover crop that can offer many potential benefits. But it can become quite problematic when it precedes corn because it creates so much residue that won’t break down and release nitrogen until later in the season. Barley and triticale could prove to be viable alternatives, Isermann says, although they sometimes struggle to overwinter.

Also keep in mind that some cover crops like hairy vetch and crimson clover can fix their own nitrogen, just like soybeans do. And tillage radishes are often selected specifically for their ability to break through compaction layers with their long taproots. Ultimately, cover crops should be seen as part of the overall crop rotation.

“Ideally, we are planting legumes in front of corn and grasses in front of soybeans,” Rothermel says, and offers some additional advice based on his experiences:

  • Do some research and talk with a farmer who already has cover crops before you start

  • Start small – pick a field where you think cover crops would benefit as your “testing ground”

  • Don’t spend a lot of extra money on equipment

  • View mistakes as learning experiences

  • Bounce ideas off like-minded farmers when possible

Joe Rothermel standing in a field

Cool, wet spring weather should prompt some additional scouting in cover crop fields, Isermann adds. In particular, look for slugs, which like to feed on corn and soybean seedlings. They thin stand counts and leave damaged plants susceptible for disease in the process.

“The problem is, there’s not much great data on slug thresholds,” Isermann says. “And just because they’re out there doesn’t guarantee it’ll be a problem. But if you’ve had issues in the past, you may want to wait until conditions get nice and warm before you plant to limit damages.”

According to a soil health assessment worksheet from the National Resources Conservation Service, answering these additional questions will help you further dial into each field’s specific needs and identify what cover crop mix will deliver the best results.

  1. What is the crop rotation?

  2. What are the types and frequency of ground disturbing operations?

  3. How many months of the year is the soil surface at least 75% covered with plants or residue?

  4. Are cover crops currently used? If so, for how many years, and how are they terminated?

  5. Is the field irrigated?

  6. Does water pond or run off after typical rainfall or irrigation events? Where in the field does that occur?

  7. Are there problems with crop emergence or early crop growth?

As a final piece of advice, Isermann reminds farmers to be kind to themselves when they dive into the world of cover crops. There’s no one “right” answer, and Mother Nature sometimes pushes the best-laid plans into murkier waters.

“Don’t let perfect get in the way of good,” he says.

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About the Author(s)

Ben Potter

Senior editor, Farm Futures

Senior Editor Ben Potter brings two decades of professional agricultural communications and journalism experience to Farm Futures. He began working in the industry in the highly specific world of southern row crop production. Since that time, he has expanded his knowledge to cover a broad range of topics relevant to agriculture, including agronomy, machinery, technology, business, marketing, politics and weather. He has won several writing awards from the American Agricultural Editors Association, most recently on two features about drones and farmers who operate distilleries as a side business. Ben is a graduate of the University of Missouri School of Journalism.

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