WEED MANAGEMENT IN BLACKGRAM [Vigna mungo (L,) HEPPER] AFTER WET SEASON RICE IN GANGETIC ALLUVIAL SOIL OF WEST BENGAL

摘要

A field experiment was conducted at the Agricultural Experimental Farm of Calcutta University, Baruipur during the summer season of 2011 on Gangetic alluvial soil to study the weed management in blackgram by different pre-emergence and post-emergence herbicides. The cultivar used for the experiment was "B67". The treatment consisted of untreated control, hand weeding twice, pretilachlor 0.75, pretilachlor 1 kg/ha, kg/ha, pendimithalin 0.75 kg/ha, metribuzin 0.5 kg/ha, quizalofop-p-ethyl 0.05 kg/ha, quizalofop-p-ethyl 0.05 kg/ ha+ 1% A/S, fenoxaprop-p-ethyl 0.08kg/ha, fenoxaprop-p-ethyl 0.08+ 1% A/S. The experiment was laid out in a randomized block design replicated thrice. Blackgram was sown on 30.03.2011 and harvested on 22.06.2011. Pre-emergence herbicides namely pretilachlor, pendimethalin and metribuzin were applied one day after sowing the crop and post emergence herbicides viz. quizalofop and fenoxaprop were applied 20 days after sowing when weeds were very tender stage. All the weed control treatments significantly reduced the weed population as compared to weedy check. Among the pre-emergence herbicides, pendimethalin found to be better than metribuzin and pretilachlor. Post-emergence herbicides quizalofop and fenoxaprop could not control broad leaf weeds, even few grassy weed could escape from their herbicidal action. Post-emergence herbicides when tank mixed with ammonium sulphate 1% exhibited better performance than their sole application. All the herbicides proved to be superior in enhancing the yield of blackgram over untreated control (50-92%). Quizalofop and fenoxaprop increased seed yield significantly (60% & 50% respectively) over untreated control but when compared with other herbicides, they were found statistically inferior treatments due to their inability to kill the broadleaved weeds. All the herbicides were found to be safe to the crop with respected to phototoxicity observed visually during summer season of 2011. From this one year investigation, it may be concluded that pre-emergence application pendimethalin or metribuzin or pretilachlor enhanced the seed yield significantly over untreated control and were as good as hand weeding twice and can be advised to the farmers from same agro-climatic condition.