Abstract

A field experiment was conducted during dry seasons of 2011 and 2012 at the ICAR-National Rice Research Institute, Cuttack to study the weed spectrum and efficacy of different weed management practices under system of rice intensification (SRI). Cyperus difformis (23.1%) was the predominant weed flora followed by Echinochloa colona (14.7%) at 45 days after transplanting (DAT) in weedy plots. Management of weeds by operating cono weeder at 15 and 30 DAT was found most effective practice (weed control efficiency 90.8% at 45 DAT) for controlling broad spectrum of weeds and realizing higher grain yield (5.79 t/ha). However, chemical weed control by applying azimsulfuron at 35 g a. i./ha applied 15 DAT was the most economic weed management option for getting higher net returns (Rs. 34, 400/ha) and benefit: cost ratio (2.82). Application of azimsulfuron also showed least energy input (8.6 x 103 MJ/ha) compared with all other weed management treatments.