A question about cover crop termination and chisel plows came up in the Organic Grain Resource and Information Network (OGRAIN) email group and was quickly answered by other farmers who have some experience on the subject. Read the full question and answers below. To post to the OGRAIN listserv email discussion group, send an email to ograin@g-groups.wisc.edu. To subscribe, send an email to ograin+subscribe@g-groups.wisc.edu.

I'm sure someone out there has tried to terminate a cover crop with chisel plow with wide sweeps. Is there anyone who has had any success with this method? Cover would be oats going into soybeans or corn. I can't find any studies trying this method, but I am pretty sure someone has tried it. I have 2 fields going into soybeans this year, both of them harvested very late with no time for cover crop establishment.

— Joe Clark

On some of our diverse spring mixes that had oats as a main component, we had good success disking and then coming back a week or 2 later with a soil finisher. In our part of northern Illinois, I can sneak in a spring mix on lightly frozen ground anywhere from early March to early April, depending on temps and snow. By mid May, the oats really aren't more than about 8-12 inches, which isn't too bad to get through. If you plant the oats extra thick, if you wait until June when they get taller, or if the ground is wet and doesn't want to flow, you might have some issues. Without seeing your specific setup and knowing how much cover crop you will be working with, I think you should be fine with the chisel and wide sweeps. You may need to pull it deep enough to get good soil flow to avoid plugging.

Also, for what it's worth, after a few years of trying some oats/pea/brassica mixes, I would advise sticking with just oats. The mix is fun, but expensive, and unless you plan on letting the legumes grow until mid-June, they don't contribute any more nitrogen than if you would spend that money on more oat seed and get all that great digestible protein.

— Jacob Landis, Northern Illinois

I've used 18" sweeps on 12" centered shanks about 4 + inches deep.  Works relatively well in uprooting established clover.  Need to roll the dirt off the clover otherwise the clover regrows, it's tenacious at surviving.  If there is rain event after chiseling clover regrows, but still much better than tandem discing.  Tractor packs clover under wheels when discing requiring many passes.  Wide sweep chisel potentially should reduce passes.  Tried high speed disc; it works well but still requires a few more passes, but I only tried it one year. Moldboard plow is more certain in terminating clover but it too requires multiple passes, soil disruption, and likely more fuel.  There are trade offs for each approach.

-Bruce Kress, Laura, Ohio

If the oats are dead in the spring that won’t be a problem. We do the same in the spring. The thing to keep in mind is;  will be if the oats got tall and the shanks cause bunching?  We have had to disk prior to a soil finisher or field cultivator to prevent bunching.  So a chisel will be similar. It all depends on if the residue clumps around the shanks. We do a cover crop of oats seeded in September/ October after our main crops. We are in central Wisconsin so the oats die over winter 

-Michael Kaltenberg, Central Wisconsin

I tried wide sweeps on my chisel plow to terminate alfalfa. They are the heel sweeps that go behind the point. I should have mowed it before working it and it plugged up a lot with full length alfalfa. When that happened they tended to ride out of the ground. Worked decent when in the ground but not at all when riding up.

-Will Glazik, Paxton, Illinois