The Strutherses supplied 600 acres of residue to DuPont in 2013. After the stover was baled, they applied hog manure, followed by one pass with a chisel plow.

Removing some residue from continuous cornfields offers an opportunity to reduce tillage, “the biggest culprit in soil carbon loss,” Penland says. The Strutherses, for example, have switched from a disk ripper to a straight-shank ripper, which “leaves more residue on the surface to protect against erosion,” Dave Struthers says.

“We’re encouraging growers to reduce tillage intensity to save costs and work towards more conservation,” Wirt says, “which will be beneficial to both growers and the land.”

Critics of residue removal — “and there are plenty of them,” says Karlen — complain that “stover harvest increases soil erosion, sediment loss and runoff.” But he’d “trade some residue removal for less tillage. Residue removal is actually preferable to tillage for soil health,” he says. “Tillage destroys soil structure and releases soil carbon.”