Effect of weed-control measures on yield, weed control, economics and energetics of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system

An experiment was conducted during 201011 and 201112 at Bilaspur, Chhattisgarh, to assess the effect of weed-control measures on grain yield, weed control efficiency (WCE) and economics of rice ( Oryza sativa L.)- wheat [ Triticum aestivum (L.) emend. Fiori & Paol.] cropping system. Application of pyrazosalfuron @ 0.02 kg/ha as pre-emergence + fenoxoprop-p-ethyl @ 0.06 kg/ha (25 days after sowing) as post-emergence resulted in sig- nificantly higher grain yield (5.7 t/ha), weed-control efficiency (76.3%) and net returns ( 41,800/ha) over other weed-management practices adopted in rice. In case of wheat, the highest grain yield (5.5 t/ha), net returns ( 36,200/ha) and weed-control efficiency (89.6%) was obtained with the application of sulfosulfuron @ 0.025 kg/ ha (25 days after sowing) as post-emergence. The highest energy productivity (0.426 kg/MJ) was observed due to application of pyrazosulfuron as pre-emergence and fenoxoprop as post emergence in rice, while in case of wheat the highest energy productivity (0.490 kg/MJ) was recorded with application of sulfosulfuron applied as post emer- gence over the other weed-management treatments.