Often cited as a way to reduce erosion or improve soil quality, cover crops are also useful in controlling weeds that have developed an herbicide tolerance, said a survey of farmers by the Conservation Technology Information Center on Wednesday. Nine out of 10 farmers reported an improvement in control of resistant weeds by allowing cereal rye to grow two feet tall before termination.
“Cover crops can be a big addition to the farmer’s toolbox to control these herbicide-resistant weeds,” said Rob Myers of the North Central Sustainable Agriculture Research and Extension, which helped pay for the survey. Funding also came from seed companies and the American Seed Trade Association. Some 1,172 farmers took part in the survey.
More than 60 percent of survey respondents said they had herbicide-resistant weeds on their farms. Almost all reported some improvement in weed control — gauged by the number of weeds and their biomass — from cover crops. Forty-five percent reported an improvement of at least 50 percent “following a solid stand of cereal rye cover crop at least 2 feet tall at the time of termination.” Nine percent said there was no change.
The CTIC report also said cover crops allowed growers to plant cash crops earlier or at the same time as in fields without them. Slightly more than half of the growers who “planted green” — seeding their cash crop while the cover crop was still growing — said the practice allowed them to plant sooner than in other fields.
Cover crops were planted on 15 million acres and 153,400 farms, according to the 2017 Census of Agriculture — a small part of U.S. cropland. Nearly 312 million acres were planted this spring to the two dozen “principal” U.S. crops, from corn, rice, and wheat to tobacco, potatoes, and peanuts.
The cover crops report is available here.