I’ve seen several articles that quote a 2022 study by researchers from Illinois and North Carolina stating cover crops can reduce yields by 5.5% in corn and 3.5% in soybeans. This study used satellite data from 2019 and 2020 across Illinois, Indiana, Iowa, Michigan, Missouri and Ohio.

The researchers acknowledge limitations to their study, including not being able to identify cover crop species, termination methods and management decisions. Still, many take this study as evidence that cover crops hurt a farmer’s bottom line. However, we have farmers in Indiana proving this system can be profitable.

The two years in the study experienced significant weather events — record wetness in 2019 and widespread severe weather in late-summer 2020. Yields in many areas were below potential with or without cover crops.

Many benefits of a cover crop being integrated into a crop rotation are long term and multi-year. The longer the system is in place, the more resilient the soil and the more benefits are realized.

Transition Years

Ken Rulon farms with his family in Hamilton County, Ind., using a long-term no-till and cover crop system. “You can’t put the transition years in the data,” Rulon says. “Everyone out here is looking at one year of data when this isn’t a one-year system.”

The previously mentioned study used fields with at least three prior years of cover crop. However, there is no information on quality of the cover crop, species or management.

Overall, these systems should be focused on return on investment instead of one-year yields. Many benefits take years to build and can be hard to quantify with dollars. Better soil structure, decreased erosion, increased infiltration and water-holding capacity, and increased organic matter are all important. With each 1% increase in organic matter, soils can hold up to 1 inch more water.

“Technology can help overcome low organic matter but doesn’t build it,” Rulon says. “Do you have enough water stored to last 41-plus days?”

With his increased organic matter, he does.

Cover Crops & Yields

“The single-biggest contributor to yield loss [with cover crops] is operator error,” Rulon says. Set yourself up for success by focusing on prescriptive cover crops to meet your goals and field conditions. Plan, find a mentor, seek advice from experts, work toward a goal, and remember that adding a cover crop may require you to adjust the cash crop varieties you plant.

You must be as committed to making cover crops successful as you are with cash crops. You can’t manage a system with cover crops the same way you manage a system without cover crops and expect success. They have very different management needs, and your nutrient management and pest management must adjust.

You wouldn’t throw corn or soybeans in the ground without researching seed options. Don’t do this with cover crops either. Sometimes mistakes or Mother Nature happens, even with the best of plans. Don’t let one bad year color your perceptions.

If you are patient through transition years, a system including cover crops can pay off. Rulon has economic data on their established system showing a $196-per-acre cost advantage over a conventional system in 2023. Yields with cover crops were similar or higher.

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