What we learned about cover crops
During a visit to Eric Miller’s farm in Piatt County, Illinois last summer, a visitor from Argentina mentioned that he referred to cover crops as “service crops.” Now that’s Miller’s new favorite phrase.
“They provide all kinds of services. We have documented significant and consistent reductions in nitrates in pipe water. That’s our main goal,” says Miller, an active cover crop user since 2011 and a cooperating farmer who has been involved in field-scale nutrient loss research projects since 2015. Additional observed include weed control, erosion control, increased organic matter and improved water infiltration.
He believes that cover crops are an asset that all farmers should consider. To help growers develop a cover crop strategy, the Nutrient Research and Education Council of Illinois funds nutrient loss reduction projects. The NREC published the 2021 Cover Crop Guide in December, echoing a main message to manage cover crops with a systems approach, or as part of your complete production system.
Farmers should consider cover crops as more than just an additional input, says Dan Schaefer, director of nutrient management for the Illinois Fertilizer and Chemical Association. “Planting a cover crop in the fall can help reduce nutrient loss, but focus on the specifics of how to manage it and achieve your row crop goals.”
He adds that the cover crop guide focuses on planting dates, rates, seeding methods and termination options. Often overlooked items, such as previously applied herbicides and their interaction with cover crops, also receive special attention. However, limits exist.
“When you think about all the specific questions farmers are going to have about using cover crops, you can’t answer all of the questions in a 14-page cover crop guide,” says Schaefer.
Build a service strategy
Where to start? If it all seems overwhelming, just start. That’s what Miller did in 2011.
“We just did an aerial application of oats to standing corn. It’s kind of a good first step for people,” says Miller. “There is no extra time needed to seed the crop. It kills winter, so you don’t have to worry about management. It gets you used to seeing green stuff in the fall and the whole process.
From there, your confidence and comfort level can dictate your next steps.
Data collected from multi-year NREC-funded research projects has shown that farmers can obtain many of the services provided by cover crops and maintain their cash crop yields when cover crops precede soybeans, explains Miller. The cover crop guide focuses on cereal rye after corn and before soybeans.
But why cereal rye and why sow before soy?
“Cereal rye is the king of cover crops,” he says. “And soybeans are a survivor that can withstand many environments and conditions.”
Plus, Schaefer says it’s easier not to till soybeans in a combination of cereal rye and corn residue from the previous year.
Miller gives the example of when you harvest corn and the cobs go into the combine.
“It’s the end of the harvest season. Now think about the residue chopped up by the corn head and distributed to the back of the combine,” he says. “It’s the start of the next agricultural season. When sized and evenly distributed, you create an ideal environment not only for cereal rye establishment, but also for later equipment passes like spring planting.
“This interaction between all field operations is what we mean by a ‘systems approach’,” concludes Schaefer.
But what about planting cover crops before corn? Schaefer says current research focuses on planting winter barley after no-till soybeans and before corn.
Ultimately, every farm, field and farmer is different. Miller and Schaefer encourage you to review the key elements outlined in the updated cover crop guide. Take a look at the Midwest Cover Crop Decision Tool to choose the best cover crop species for your operation.
And learn from the experiences of other farmers. Talk to farmers who are successfully using cover crops, Miller says. Finally, give an honest self-assessment of your desire for cover crops to provide services for your operation.