The discussion about cover crops nearly always comes around to the best method of killing it. Crimping is getting some attention, for more than just termination.
The practice of using rollers to flatten plants in the spring is not new, especially in organic operations, but more conventional farmers are seeing some benefits.
Joseph Curless is one of them. Curless, who farms in the Illinois River watershed near Havana, Illinois, has been experimenting with the practice for two years. While it is too early to proclaim success, he is encouraged.
He placed Yetter Devastator roller attachments on his tractor and 16-row planter in a field of chest-high cereal rye that was aerially sown in the fall. His main emphasis is weed suppression.
“The weed thing is getting out of control,” Curless said. “Glyphosate is losing ability to take care of some of the weeds.”
His personal research project came about by accident about seven or eight years ago, when aerial application of cereal rye in a field along the Illinois River bluffs malfunctioned in one spot, creating 3-feet skips.
“The next spring there was all kinds of marestail there in the skipped area,” Curless said. “We were getting some weed suppression where the broadcast application took hold. The weeds are there, but they’re suppressed. They’re very short and stubby, and are controlled with some of our normal tools.”
Crimping is more commonly a practice used by organic farmers, who have limited options in weed control and nutrient application. But with the increase of herbicide-resistant weeds, it is getting a look by conventional farmers interested in weed control along with other benefits of covers.
Lowell Gentry, a University of Illinois research specialist in natural resources and environmental sciences, has done limited work. But he believes crimping has the potential to reduce weed pressure.
“I think it is, but we don’t have the data,” he said. “We tried it one time, but we still used herbicide. We need a controlled plot where we crimp half and not crimp the other half.”
Crimping cover crops — often cereal rye — snaps the stems of the plants, which fall over, die and create a thatch on the field. That can prevent some growth of weeds by acting as a canopy. The breakdown of the cover crop also provides other benefits, such as soil conservation, moisture retention and improving organic matter.
Camille Lambert, an agronomist with Beck’s Hybrids, has also done some research into crimping. Workers at the seed company’s Effingham, Illinois, location attached a roller bar to a tractor and drove it backward over mature cereal rye in a test plot there.
“It weighs only about 700 pounds, so it’s not super heavy,” she said. “The rye was only about a foot-and-a-half tall and had less efficacy because it hadn’t jointed yet. If you crimp it over, it’s going to stay down.”
Ironically, crimping followed by herbicide application resulted in more weeds.
“When I add Roundup PowerMax I have more waterhemp,” she said. “Why? Because of breakdown of the biomass. It started to break down faster. Crimping by itself snapped that stem but took longer to decompose.”
Curless is a believer, though the results aren’t in yet. His land is yellow and gray clay with less than 0.5% organic matter.
“It’s just difficult ground,” he said. “If I make this mat of thatch, that helps me suppress the weeds and build organic matter over time. I can’t prove that, but it shows promise. I think it’s possible that it can reduce herbicide use. But I don’t think you can eliminate it.”