EFFECT OF SOYBEAN (GLYCINE-MAX) CULTIVAR, TILLAGE, AND RYE (SECALE-CEREALE) MULCH ON SICKLEPOD (SENNA-OBTUSIFOLIA)

Field studies were conducted to determine the effect of soybean cultiv ar, tillage, and rye mulch on sicklepod growth. Early-season sicklepod height was not affected by tillage or mulch. Sicklepod was tallest wh en grown with 'Centennial' or 'Biloxi,' the tallest cultivars, and sho rtest when grown with a dwarf isoline of 'Tracy M,' the shortest culti var. Soybean competition reduced early-season weed density by 30 to 50 %, depending on the cultivar. Centennial and dwarf Tracy M caused a 30 % reduction in early-season sicklepod biomass while 'Sharkey' and Bilo xi reduced sicklepod growth by 40%. By late-season, sicklepod biomass reduction ranged from 18% (Tracy M) to 55% (Biloxi) and was directly r elated to soybean cultivar height. Mulch or no-tillage independently r educed sicklepod biomass.