Integrated weed management in direct-seeded rainfed rice (Oryza sativa)

A field experiment was conducted for three years during rainy ( kharif) season of 2006-2008 at Almora, Uttarakhand to study the effect of different weed control methods on weed infestation, energy use efficiency, pro- ductivity and profitability of direct seeded rice ( Oryza sativa L.) under rainfed conditions. On an average, a weed population of 627/m2 was recorded in the weedy check plots. The grain yield decreased by 78.5-94.8% due to sea- son-long weed-crop competition as compared with hand weeding (20 and 40 DAS). The highest weed-control effi- ciency and loweet nutrient uptake by weeds was recorded with butachlor + hand weeding (40 DAS) closely fol- lowed by hand weeding twice (20 and 40 DAS). Both these treatments recorded higher grain yield (2.21-2.36 t/ha) compared to other treatments. Butachlor + weeding with wheel-hoe (40 DAS) was the next best treatment. This treatment required less energy input compared with all other weed control treatments. Butachlor + hand weeding and butachlor + wheel- hoe registered the highest energy use efficiency (10.23 and 9.75, respectively) and net re- turns ( 11,868 and 11,299/ha, respectively) compared with other treatments. The benefit: cost ratio was the high- est (1.90) with butachlor + weeding with wheel-hoe closely followed by butachlor + hand weeding and butachlor + long-handled khurpi.