It’s the first week of September, and Ryan Britt is seeding a cover crop of annual ryegrass, tillage radish and crimson clover into wheat stubble. Britt raises corn, soybeans, winter wheat and cattle in north-central Missouri. He is battling herbicide-resistant waterhemp and marestail in his continuous no-till operation. He plants cover crops “primarily for weed management.”

Annual ryegrass helps suppress waterhemp, Britt says. And the residue shades the ground, inhibiting waterhemp germination during the growing season, says his agronomist, Jason Young of AgriVision, Salisbury, Mo. University of Arkansas 2009 and 2010 research found that a fall cereal rye cover crop significantly reduced glyphosate-resistant Palmer amaranth emergence in soybeans the next season. Palmer amaranth is a close cousin to waterhemp.

The cover crop doesn’t eliminate the need for herbicides, Britt says, but it does cut weed pressure. He also plants soybeans in 15-inch rows to help manage weeds. Two other rotation crops, wheat and alfalfa, also aid weed management. 

herbicide diversification plan