Published Apr 20, 2011

Tips for Killing Cover Crops
By Sarah Carlson
Farmers in Iowa are preparing corn and soybean fields for planting this spring; in some cases a cover crop was planted on this ground last fall. How do you manage a cover crop in spring, such as rye, to kill it prior to planting corn or beans?
Rod Swoboda
Cover crops are a management practice that’s catching on with more farmers each year. Last fall a number of Iowa farmers planted a cover crop, usually rye, in fields to help protect against soil erosion over the winter and in early spring.

How do you handle such fields this spring, to kill the cover crop, so you can plant corn or soybeans in that field? Sarah Carlson, research and policy director for Practical Farmers of Iowa in Ames, provides the following answers and guidelines for managing cover crops in the spring.

“If you are a farmer and have a winter cover crop in the field, we at PFI recommend you check it now if you haven’t already,” she says. “We remind farmers to make sure they stay on top of cover crop management in the spring.” Carlson has worked with a number of farmers cooperating in PFI sponsored on-farm trials using cover crops the past several years. For the best success, Carlson says PFI recommends the following steps this spring.

Recommendations for spring killing of cover crops

1)     If spring conditions are dry, plan to kill the cover crop sooner than later.

2)     If planting corn, kill the cover crop 8 to 10 days prior to corn planting.

3)     If planting soybeans, cover crop can be killed closer to planting. Some farmers are no-till drilling soybeans into a living cover crop and then using a “burndown” 1 to 2 weeks following planting to kill the cover crop. Caution: try this new method on a few acres as you get started.

4)     Herbicides are not the only method for killing a cover crop. Using cattle to graze off the cover in the spring or mowing it then followed by tillage can kill the cover crops.

5)     If using tillage only, don’t let the cover crop get taller than 6 inches high.

6)     If using herbicides use the legal, labeled rate and pay attention to the weather conditions prior to spraying.

Also, check out PFI’s Cover Crop Business Directory to find area businesses that can custom kill cover crop in your field. “The directory includes a list of aerial applicators and seedhouses that can help you add the practice of growing a cover crop to your farming operation,” notes Carlson.

Click here for the Cover Crop Business Directory.