For Marshall County Farm Bureau member Wade Dooley, cover crops are a management tool and a source of feed for his 80 cow/calf pairs.

"I’m not going after yield boost on grain crops. I’m going after feed for my cows. That’s a big difference than guys going after increased yield," he said.

Dooley and his dad grow corn, hay, popcorn, pumpkins, small grains, soybeans, squash, watermelon and cattle on about 1,200 acres, most of it on Iowa River bottom ground. The farm’s location near the river makes growing crops and grazing difficult because of flooding, he said.

"In the last...