Reducing weed competition

Cover crops like cereal rye reduce weed competition in soybeans but many vegetable legume growers have yet to adopt the practice due to the potential for reduced germination and yield in thick residue.

A new study out from the University of Illinois and USDA-ARS indicates early-terminated rye could be a promising part of an integrated weed management program for some vegetable legumes, including edamame.

Ecologist Marty Williams, an affiliate professor in the Department of Crop Sciences at Illinois, said the more cover crop biomass you have, the better the weed suppression. They found a sweet spot in an earlier experiment with edamame when rye was terminated at tillering and then planted into the stubble.

In edamame and snap bean, early-terminated rye reduced weed biomass by 53 percent and 73 percent, respectively, compared to bare soil. Williams found no reductions in edamame establishment or yield.