What is in this article?:
A recent survey of farmers by the Conservation Technology Information Center found that cover crops boosted corn yields by 9.6% during the drought year of 2012, and soybean yields by 11.6%. That’s compared to side-by-side fields with no cover crops.
However, cover crops can also lower cash crop yields if not managed correctly, warns Hans Kok, Conservation Cropping Systems Initiative, Indiana. In a dry spring, the cover crop may use up valuable soil moisture that the cash crop needs, says Joe Lauer, University of Wisconsin corn agronomist.
That’s why beginners should start small, Kok says. Instead of planting an entire field of cover crops, he suggests that first-timers put in a few strips at least as wide as the combine. “The combine yield monitor will show you if there is a yield difference.”
Cover crops' roots anchor the soil and nutrients when other crops aren't there to do the job. This is cereal rye.
How do I kill the cover crop?
Many common cover crops, such as oats and oilseed radishes, die over the winter. Others, such as annual ryegrass and cereal rye, usually survive the winter and are killed in early spring with glyphosate or other herbicides.
But managing the spring burndown can be difficult, especially for beginners, warns cover-crop agronomist Hans Kok, coordinator of the Conservation Cropping Systems Initiative in Indianapolis, Ind. In a wet spring, for example, cereal rye can grow very fast and produce heavy residue, which may interfere with planting and tie up. Annual ryegrass can be hard to kill with glyphosate when it’s cool, because the herbicide doesn’t translocate well, Kok says.
Wait to spray until the cover crop greens up and is actively growing, Bowers says. Spray full rates of glyphosate on a sunny day when the temperature is high enough for good activity, Kok adds. And pay careful attention to spray water quality, pH, hardness and spray coverage. Stop spraying by mid-afternoon, Robinson advises.