Cover Crops, a Farming Revolution With Deep Roots in the Past
Categories: On The Farm
Last fall, the Berns brothers were recognized as White House Champions of Change for Sustainable and Climate-Smart Agriculture. “We have been kind of surprised at how fast our business has grown,” Keith said. “The reason is that because it’s working agronomically and doing what it’s advertised to do.”
Modern farming practices like applying fertilizer and herbicides have helped farmers increase yields and reduced labor, but they have also unintentionally interfered with root systems and disrupted underground microbial activity and insect life that are vital to plant and soil health. (Many farmers deploying cover crops continue to use herbicides, although often less than they did in the past, but they often can do without fertilizers.)
“We’ve concentrated on the physical and chemical aspects of farming but not the biological,” said Dan DeSutter, who farms 5,000 acres near Attica, Ind.
Mr. DeSutter began fooling around with cover crops about 17 years ago, after Purdue University used one of his fields for research trials. One spring he was repairing a drainage tile in the test field and came across the deep, webbed root system that some Oregon ryegrass had put into the soil.
Mark Anson, center, has planted cover crops between harvests on 13,000 of the 20,000 acres his family farms in Indiana and Illinois. Credit Andrew Spear for The New York Times
“I thought to myself, I have been pulling the guts out of my tractor to remove compaction 14 inches deep with a ripper,” Mr. DeSutter said, “and this plant has just bored a system of micropores four feet deep between cash crops all on its own.”
The roots he stumbled across had created a natural aeration system that helped conserve water and trap nutrients in the soil, which would otherwise be prone to leaching. “That was the aha! moment,” he said.
Today, all 5,000 acres he farms are sown after the harvest of corn and soy with a mixture of as many as 12 different crops, including sunflower, sorghum, buckwheat, turnips and hairy vetch, each of which delivers a different benefit. Most die off in the winter and decompose, leaving behind a rich layer of organic matter that gradually sinks into the earth. Farmers use a planter or seed drill to punch the seeds for their cash crops into the decaying cover crop.
Before cultivation, Indiana was blanketed in prairie grasses and forest, and the carbon content of the soil was as high as 10 percent in places. Today, after decades of tillage, which moves carbon from the soil into the atmosphere, and monocropping, the level on many farms is below 2 percent, Mr. Fisher said. Cover crops restore organic matter back into the soil, at a rate of about 1 percent every five years.
“As we put carbon back into the soil, it gives us a bigger tank to store water naturally,” Mr. DeSutter said. “This is one way we build resilience into the system.”
The adoption of cover cropping has been especially rapid in Indiana — about one million of the 12.5 million acres of farmland there are planted with cover crops between harvests. A strong collaboration between Purdue University and state and federal farm services gave birth to the Indiana Conservation Cropping Systems Initiative, a program that offers education and research to farmers in the state.
Rob Myers, director of extension programs for the north central region of SARE, and a professor at the University of Missouri, said Maryland also ranked high in the use of cover crops. The state reimburses farmers for the cost of cover crop seed and has been informing them about the impact that fertilizer runoff has on Chesapeake Bay.
Despite the support for cover cropping in Indiana, there is still resistance to change. Farmers are notoriously reluctant to offer their neighbors advice about farming, and cover cropping carries with it an implicit criticism of practices — reliance on fertilizers and pesticides, and so forth — that farmers for the last generation have used to increase productivity and reduce work.
Forage turnips are one of the cover crops Dan DeSutter uses on his farm. Credit David Kasnic for The New York Times
“All those old guys sitting around shooting the breeze at the feed store get real quiet when I pull up,” Mr. DeSutter said, only half in jest.
Neighbors have made pointed comments about his “messy” fields. The fields sown with a cover crop cocktail are often blanketed in dying, decaying and thriving plants at the same time. In December, spindly black stalks, the remnants of sunflowers, shot up here and there from one of Mr. DeSutter’s fields, which were covered in a yellowing broadleaf and bright green hairy vetch.
But the biggest obstacle to more farmers adopting cover crops is the lack of data and research on their benefits. “Fewer of our neighbors think we’re crazy than when we started planting cover crops, but there’s still a lot of skepticism out there,” said Rodney Rulon, whose family farms 6,200 acres in northeastern Indiana and plants about four-fifths of them with cover crops.
Rulon Enterprises, the family business, has begun collecting data on some of its fields. He has found, for instance, an increase in organic matter and higher corn yields — an average of 12.8 bushels an acre more in one of his cover-cropped fields, said Mr. Rulon, who shared some of this data in December at the 70th Corn & Sorghum Seed Research Conference.
“You really start seeing a difference in your soil within two or three years,” Mr. Rulon said.
The Rulons spend about $100,000 a year on cover crop seed, or about $26 an acre. But they also saved about $57,000 on fertilizer they no longer needed, and bigger yields mean about $107,000 in extra income.
Including the value of improved soil quality, less erosion and other improvements, Mr. Rulon estimates that Rulon Enterprises gets about $244,000 of net economic benefit from cover crops annually, or a little more than $69 an acre.
The federal government is mulling ways to persuade farmers to adopt cover cropping. There is a small subsidy system; Rulon Enterprises, for instance, gets $40,000 to help offset the cost of cover crops and support other conservation practices.
But Mr. Rulon and Mr. DeSutter believe that landowners are the real key to taking cover crops mainstream. Most farmers work some fields leased from absentee owners, and thus have less incentive to maintain and invest in improving soil quality on that land.
“Why should landowners see the value of their land diminished because the soil on it has become unhealthy?” said Mr. DeSutter. “I’d like to see landowners give preferential treatment to farmers who are working to improve the value of the land they lease by using cover crops.”