WEED AND CORN (ZEA-MAYS) RESPONSES TO A HAIRY VETCH (VICIA-VILLOSA) COVER CROP

Field studies were conducted in 1990 and 1991 to determine the effects of com planting date and hairy vetch control method on the efficacy o f fall-planted hairy vetch as a weed-suppressive cover crop for no-til l com. Glyphosate controlled hairy vetch when applied at the early bud growth stage (April), but hairy vetch residue provided no weed contro l compared to the weedy check. Mowing was not an effective means of su ppressing hairy vetch at the early bud stage. Untreated hairy vetch re duced weed biomass 96% in 1990 and 58% in 1991 but reduced yield over 76% in April-planted com. There was no competition of untreated hairy vetch with com when com planting was delayed until May or June (mid- o r late-bloom growth stages of hairy vetch). Com planted in May into un treated hairy vetch yielded similarly to com planted in a no-cover wee d-free check.