Forgey arrived at his cover-crop formula through trial and error. Recently, he cut the proportion of brassica crops in the mix because he found that they depleted the residue too quickly, hurting yields in dry years. “Now I use a lot more grasses,” which create a more desirable carbon-to-nitrogen ratio.

Central South Dakota usually gets about 18 in. of rain a year. In dry years, Forgey cuts back a bit on the seeding rates. “But I’m not concerned about the amount of moisture lost to the cover crop,” he says. “Our fields with cover crops have just as much moisture as fields without cover crops.”

In fact, Beck says, “Water used by a cover crop during the non-crop period can often be regained before and during the growing season because of better infiltration and reduced runoff.”

Hard frost kills Forgey’s cover-crop mixes, so overwintering hasn’t been an issue. “In a mild winter, some plants may survive, but it doesn’t really matter. We plant corn into the cover crop and take out any survivors with our regular herbicide application,” he says.

Cover crops are an added expense, Jasa points out, and the benefits take a few years to accrue, especially if you don’t graze livestock. “That’s one reason most people aren’t doing this,” he says.

A three-year grant from USDA Sustainable Agriculture Research and Education (SARE) helped Forgey get started. To lower his costs, he raises some of his own cover-crop seeds, including radishes and field peas. He trades lentils for his neighbors’ oats and flax seed. That holds down his cash outlay to about $8/acre – a third of what he would have to spend to buy the cover-crop seed mixes. Cronin Farms also grazes about half the cover-crop acreage in the fall, earning an immediate economic return.

Yield responses to cover crops have been mixed so far, Forgey says. In 2008, corn yields were higher on cover-cropped ground than on non-cover-cropped ground. In the following crop, sunflowers, there was no yield difference. And in 2010 – a dry year – spring-wheat yields were lower on the cover-cropped ground.

But Cronin Farms’ overall yield trend is increasing, says Forgey, a frequent speaker at no-till and cover-crop events. He considers both strategies a long-term investment in soil quality. “It’s farming for the future.”

Forgey has been a part of Cronin Farms for more than four decades, and he harbors “a deep love and respect for this land. I’m a firm believer that if you take care of the land, the land will take care of you. That’s the philosophy on this farm.”