DES MOINES, Iowa– Called cover crops, they top the list of tasks that American farmers are told will build healthy soils, help the environment and combat climate change.
However, after years of incentives and encouragement, Midwest farmers planted cover crops on only about 7% of their land in 2021.
That percentage has increased over the years, but remains small in part because, although farmers receive additional payments and can see numerous benefits from cover crops, they remain cautious. Many worry that the practice will hurt their results, and a study from last year indicates they might be right.
Researchers using satellite data to examine more than 90,000 fields in six Corn Belt states found that cover crops can reduce cash crop yields – bushels per acre. The lower the yield, the less money farmers make.
“I don’t want to give up on it, but as far as planting cover crops, it’s kind of hard for me,” said Illinois farmer Doug Downs, who plants cover crops on only a portion of his land in a relatively flat central region. -eastern Illinois.
Cover crops are plants grown on otherwise bare cropland. While crops like corn and soybeans are growing or shortly after harvest, farmers can plant species like rye or red clover that will grow through the winter and spring. They stabilize soil, reduce fertilizer runoff, store carbon in plant roots, and potentially add nutrients to the soil.
The practice is key to government efforts to sequester carbon on farmland to help reduce climate change, as there is general agreement that planting the right crops out of season can pull carbon from the air and keep it underground in the roots of crops. the plants.
The U.S. Department of Agriculture promotes cover crops through several programs, starting with $44 million in payments during fiscal 2023 from the agency’s Natural Resources Conservation Service for more than 4,700 contracts to plant them in more than 850,000 acres (344,000 hectares). Additional funds were available for conservation practices, including cover crops, through the Inflation Reduction Act. Another program provided $100 million in additional benefits through federal crop insurance coverage to farmers who plant cover crops.
There is increased interest in cover crops for carbon storage, although effectiveness depends on soil, plant variety, temperature and other factors.
The Natural Resources Defense Council has placed such a premium on cover crops that it recently launched a social media campaign with Nick Offerman, featuring the Parks and Recreation actor buried in the ground while promoting cover crops. practice. The environmental group has encouraged Congress to give farmers more lucrative financial incentives to plant crops.
The NRDC points to studies that have found that cover crops do not necessarily reduce the yield of cash crops and can boost growth. And Lara Bryant, the group’s deputy director of water and agriculture, notes that while the overall percentage of farmers planting cover crops is small, the acreage has increased to between 50% and about 5% of U.S. cropland. .between 2012 and 2017, based on USDA data from the most recent year. is available.
“We have a long way to go, but we’ve come a long way in a short period of time,” Bryant said.
However, the 2022 satellite study found that yields decreased by an average of 5.5% in corn fields where cover crops were used for three or more years. In the case of soybean fields, the drop was 3.5%. Declines varied depending on factors such as cover crop type, soil moisture and soil quality.
“I was surprised that it was so negative,” said David Lobell, an agricultural ecologist at Stanford University who worked on the study published in the journal Global Change Biology with researchers from Illinois and North Carolina. “We rechecked everything and were a little surprised.”
The study found that rye, the most widely used cover crop, is especially prone to reducing yields, Lobell said. Rye is less expensive than many cover crops and grows well in many soil types.
The study examined agricultural fields in Illinois, Iowa, Indiana, Michigan, Missouri and Ohio, using satellite images. Lobell said the details of an individual field are less precise than field studies, but by examining thousands of fields, researchers can reach precise conclusions.
The researchers said farmers need more technical help in choosing and maintaining cover crops, as well as more payments from the government or the food industry to offset potential yield losses. The federal government and at least 22 states offer financial incentives to farmers, and food companies like General Mills and PepsiCo pay more to farmers who plant cover crops.
Terry Cosby, head of the USDA’s Natural Resources Conservation Service, acknowledged that establishing effective cover crops can take time and some experimentation, but said farmers who follow them should see significant benefits. He noted the Biden administration’s allocation of $19.5 billion for climate-smart programs over five years and that federal, state and university extension services can provide technical advice.
“It’s going to take some trial and error,” Cosby said. “It could fail, but in the long run… it’s been shown that you can have a lot of success with some type of cover crop.”
Downs, the Illinois farmer, has tried incorporating cover crops into some of his operations, especially to control weeds. But he says it hasn’t been easy.
In 2019, Downs planted rye in one field, but did not plant it in an identical field across the road. The spring was wet and the rye field was so soggy that he couldn’t get in for weeks to kill the cover crop and plant soybeans, resulting in a smaller crop.
“It cost me $250 an acre to grow a cover crop and I spent $50 an acre to do it,” Downs said.
Farmers do not typically harvest or sell cover crops; They often use herbicides to kill them before planting their main crop.
Less than 20 miles (32 kilometers) away, fourth-generation farmer Curt Elmore has been “dabbling” in cover crops for a decade, planting varieties like oats and rye on parts of the 2,000 acres (809 hectares) he farms. .
Elmore seeds cover crops by plane before harvesting their cash crop, but cover crop growth has been spotty and is not worth the $40 per acre cost.
Elmore said he will keep trying, but it appears that in his area of Illinois, more payments from governments or companies will be needed to convince many additional farmers to adopt the practice.
“If this is an imperative, then someone is going to have to pay for it,” he said.
Joe McClure, research director for the Iowa Soybean Association, said the Stanford study largely confirms his organization’s research, although he thought university researchers should conduct a field study to verify their satellite analysis.
McClure said more financial support would help farmers avoid having to choose between planting cover crops and losing money.
J. Arbuckle, a professor in Iowa State University’s sustainable agriculture program, said it’s important to be open with farmers about potential yield reductions and how they can be mitigated over longer periods, such as six or seven years.
Even then, Arbuckle said, it can be difficult to convince farmers to try cover crops because, despite significant environmental benefits, a small drop in cash crop yields can mean a big cost.
“Even a hit of a bushel, whether we’re talking about a bushel per acre or over a thousand acres, that’s a lot of money,” he said.
This story has been updated to correct the name of the Natural Resources Defense Council.
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