Common ragweed is an annual weed problem after winter wheat harvest in southwest Michigan. Although an interseeded cover crop of red clover is known to reduce weed populations in winter wheat stubble, the most effective rates and cultivars for weed suppression under Michigan conditions have not been identified. Three red clover cultivars were planted in March at three seeding rates in established winter wheat; after wheat harvest, a section of each plot was mowed to mimic forage harvest of clover. The experiment was repeated in 2 yr. Mowing significantly reduced common ragweed biomass each year. All cultivars and seeding rates were equally effective at significantly reducing common ragweed biomass in each year, despite the variation among years, cultivars, seeding rates, and mowing treatments in production of clover biomass.

Nomenclature: Common ragweed, Ambrosia artemisiifolia L. ;ns³ AMBEL; red clover, Trifolium pratense L.; winter wheat, Triticum aestivum L.

Additional index words: Cover crops, weed management.