Integrated weed management in rainfed upland rice (Oryza sativa)

Field experiments were conducted at Naira, Andhra Pradesh for two consecutive rainy (kharif) seasons of 2005 and 2006 to study the efficacy of different herbicides applied alone and their integration with star weeding in rainfed upland rice (Oryza sativa L.). The reduction in grain yield due to uncontrolled weed growth was 62.6% compared with weed-free check. Pre-emergence application of metsulfuron methyl 10% + chlorimuron ethyl 10% @ 6.0 g/ha resulted in better weed control but the improved efficacy could not be translated to better yield due to its phytotoxicity on rice. Among the herbicide treatments, pre-emergence application of oxadiargyl @ 80 g/ha + working with star weeder at 40 days after sowing, followed by pre-emergence application of oxadiargyl @ 80 g/ha alone resulted in improved weed-control efficiency, better yield attributes, and higher grain and straw yields, besides fetching higher net returns and benefit: cost ratio compared with weed-free check.