Three questions to help you see both the risks and rewards of planting cover crops
Are cover crops all peaches and cream?
Not exactly, say the experts. Cover crops can improve soil health, including increased infiltration, organic matter and biological activity, as well as reduce soil erosion and compaction. Add in a greater ability to reduce nutrient loss, and it is easy to see why cover crops are popular.
1. True or false? Farmers can expect success after a year of planting cover crops.
FALSE. Successfully using cover crops involves a learning curve.
“If you converted to long-term no-till, think back to how long it took to achieve measurable results,” says Dick Lyons, Illinois Council on Best Management Practices (CBMP) cover crop specialist. “A cover crop is usually growing on the land for as long as your soybean crop, just at a different time of the year. You need to give it the planning and management it is due.”
Jenny Mennenga, soybean farmer from LeRoy, Illinois, agrees. “We started planting cover crops in the fall of 2008 with 30 acres of cereal rye that would be planted in soybeans in 2009.”
Mennenga was able to get the cover crop established in cool, wet weather, but she later had trouble killing the cereal rye when it was time to plant beans. They were able to stunt it and plant soybeans, but with lots of biomass remaining. Things looked good, she says, until the second or third trifoliate, when slugs girdled the beans and required a replant on July 30.
“Everything that could go wrong, did,” says Mennenga, who has learned to adapt since that first fateful season. “Starting with 30 acres was the way to go. You need to start small and learn what works on your farm. Getting the cash crop planted is key.”
2. True or false? Cover crop stands should be thick and lush.
FALSE. The best cover crop for your fields may not be as pretty as a picture.
“The photos you often see are of the best stands, which has contributed to the impression that cover crop stands should be thick,” says Joel Gruver, Western Illinois University soil science associate professor. “A thick stand increases cost, increases risk of interference with the subsequent crop and is not necessary to achieve significant conservation benefits.”
The optimum stand depends on what you want to accomplish. Lyons explains that cereal rye for weed control may require a bushel or more per acre, but simply working to improve soil health may require one-half to two-thirds of that. And if cover crop forage will be grazed or is in an erosion-prone area, consider planting a higher rate than in a less-intensive management situation.
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