Effect of herbicides on mixed weed flora and economics of direct seeded rice (Oryza sativa L.)

The present experiment was conducted at Instructional cum Research Farm, Department of Agronomy, IGKV, Raipur (C.G.) during Kharif season 2013 to find out the most effective weed management in direct seeded Rice. The eleven different weed management practices were laid out in Randomized Block Design (RBD) with three replications. Rice variety “MTU-1010” was grown as a test crop. Rice was sown on 20th June, 2013 with a spacing of 20 cm (row to row). The crop was fertilized with 100, 60 and 40 kg N, P2O5 and K2O ha-1, respectively. The results of experiment indicated that lower weed density and dry matter accumulation at initial period of crop growth responded significantly better to oxadiargyl @ 100 g ha -1 at 2 DAS followed by bispyribac sodium @ 25 g ha -1 at 25 DAS (T3) and this was followed by pyrazosulfuron @ 20 g ha -1 at 2 DAS followed by bispyribac sodium @ 25 g ha -1 at 25 DAS (T4). At later period of growth, lower weed density and dry matter accumulation under pendimethalin @ 1000 g ha -1 at 2 DAS followed by bispyribac sodium @ 25 g ha -1 at 21 DAS followed by hand weeding at 45 DAS (T5) favoured significant enhancement in number of effective tillers, weed index, straw and grain yield. The experimental field dominated by mainly Echinochloa colona, Alternanthera triandra, Cyperus iria, Spilanthes acmella, Cyanotis axillaris throughout the crop season. It was also observed that all the herbicide treatments were effective and significantly enhanced the grain yield over control.