Abstract
Weeds pose a major threat to the yield ofmungbean crop. Allelopathy has emerged as a recent tool for manipulating the growth of different plant species. In this study. selective allelopathic character of sorghum was explored for controlling weeds in mungbean. For this purpose. one. two and three sprays of sorgaab were compared with one and two hand-weedings alone and one sorgaab spray + one hand-weeding. Three foliar sprays of sorgaab at 15. 30 and 45 days after sowing reduced the dry weight of Cvperus rotundus, Convolvulus arvensis and Portulaca oleracea by 50. 60 and 75%, respectively. while Trianthema portulacastrum remained unaffected. Sorghum mulching ((tdO and 15 t ha' reduced weed density by 25 and 27"1". Maximum .~ reduction in weed dry weight (84%) was achieved by two hand-weedings. Increase in mungbcan grain yield due to three sorgaab sprays. sorghum mulching (li110 and 15 t ha' and two hand-weedings was 19,7. 13 and 22%, respectively over control. Economic and marginal analysis showed the dominance of employing three sorgaab sprays over sorghum mulching and hand-weeding due to higher costs involved in latter cases: G Key words: allelopathy, sorgaab. sorghum mulch, weed control
