Effect of live mulches, cover crops and herbicides on weed flora, growth and yield of direct-seeded rice (Oryza sativa)

Abstract

A field investigation was conducted during the rainy season of 2014 and 2015 at Varanasi, Uttar Pradesh, to study the effect of live mulches, cover crops and herbicides on weed flora, growth and yield in direct-seeded rice (Oryza sativa L.). At 60 days after sowing (DAS), amongst the weed management treatments, Sesbania cover crop followed by (fb) bispyribac Na 25 g/ha + azimsulfuron 30 g/ha at 15 DAS reduced weed density of various weeds and dry weight than sunnhemp (Crotalaria juncea L.) cover crop fb bispyribac Na 25 g/ha + azimsulfuron 30 g/ha at 15 DAS thus resulting in the lowest weed index except hand weeding at 15 and 35 DAS. Sesbania cover crop fb bispyribac Na 25 g/ha + azimsulfuron 30 g/ha at 15 DAS markedly improved plant height, tillers/m2 , dry-matter accumulation, leaf-area index, chlorophyll content and yield attributes, viz. panicle length, panicle weight, panicles/m2, grains/panicle and 1,000-grain weight. Sesbania cover crop fb bispyribac Na 25 g/ha + azimsulfuron 30 g/ha at 15 DAS improved the grain and straw yields with higher gross returns, net returns and benefit: cost ratio than sunnhemp cover crop fb bispyribac Na 25 g/ha + azimsulfuron 30 g/ha at 15 DAS. Sesbania cover crop fb bispyribac Na 25 g/ha + azimsulfuron 30 g/ha at 15 DAS exhibited lower nutrients (NPK and Zn) uptake by weeds and higher nutrients (NPK and Zn) uptake by crop than hand-weedings at 15 and 35 DAS.