Planting a cover crop in late summer into a standing crop of soybeans, or planting a cover crop in a field in the fall immediately after harvesting soybeans or corn, is an idea more farmers have started putting into practice the past few years in the Midwest. "Seeding cover crops to protect your land from erosion over winter is not a new practice, but we've not done this a lot in Iowa," observes Tracy Blackmer, director of research for the On-Farm Network, a program offered by the Iowa Soybean Association.
Recently though, there's been more interest in using cover crops here in Iowa. There are several potential benefits from establishing cover crops, if they're managed in the right way and are planted in the right place. No one will argue that the establishment of a cover crop will help control soil erosion. But there are many other issues – both good and bad that may have effects in some places and not others.
"In general, most Iowa farmers have not made use of cover crops, so most of our farmers have a very limited understanding of how to capture the benefits and avoid the negatives," Blackmer observes.
After the drought of this past summer and a less-than-stellar corn yield, many farmers in Iowa have asked whether they should plant a cover crop this fall to "soak up" some of the nitrogen left in the soil. The idea is to capture that leftover N this fall, as the cover crops will take it up, instead of letting it escape. Then when the cover crop is killed next spring, the nitrogen will be available for the corn planted in that field in 2013.