Performance of weed management practices for different establishment methods of rice (Oryza sativa L.) in dry season

Effect of rice establishment methods and weed management practices on associated weeds and grain yield of rice was studied at BRRI farm Gazipur and BRRI farm Bhanga, Faridpur District during dry seasons of 2006 and 2007. Seven weed control treatments were imposed inside three planting methods in Split Plot under RCBD. Herbicide MCPA 500 @ 500g a.i. per ha showed some phytotoxicity in broadcasting and drum seeded system where other treatment combinations did not show any significant phytitoxicity on crops. Grass type weed were dominant in direct wet seeded rice whereas sedges and broad leafs were dominant in transplanting method of rice. Weed control efficiency varied from 80 to 85% during 2006 and 88-91% in 2007 against different weed control treatments. Weed number and weight was significantly higher in broadcast and drum seeded method resulting lower weed control efficiency than transplanting method. Different groups of herbicide + one hand weeding gave statistically similar yield compared with weed free treatments except MCPA500 @ 500g a.i. per ha + one hand weeded treatments. Higher panicles m-2 in broadcasting and drum seeded method led to higher grain yield than transplanting method. Interaction effect of ethoxysulfuron 150WG @ 15g a.i. per ha + one hand weeding in broadcasted method and pretilachlor 500EC @ 500g a.i. per ha + one hand weeding under drum seeding produced higher grain yield, whereas other combinations of treatments produced intermediate grain yield. Broadcasting and drum seeding method produced lower grain yield in unweeded condition as compared with transplanting method under the with same condition. It is thus, concluded that for realizing higher yields of rice drum and broadcast methods should be integrated with ethoxysulfuron and pretilachlor @150 and 500 g a.i. per ha, respectively in combination with one hand weeding.