Weed Dynamics and Production Potential of Direct-Seeded Rice Cultivars as Influenced by Weed Control

Abstract

The field study was undertaken during summer season of 2013 at Experimental
Farm, Annamalai University to evaluate the rice cultivars and weed management effects on
weeds growth and yield of direct-seeded rice (DSR) cultivars. The associated weed flora
include Echinochloa colonum, Echinochloa crusgalli, Cynodon dactylon as grasses; Cyperus
rotundus, Cyperus iria as sedges; Caesulia auxillaries and Eclipta alba as broadleaved
weeds. Bispyribac-sodium + azimsulfuron (25 + 35 g/ha) + 0.25% NIS as post-emergence
at 15-20 DAS was found to be most effective in minimizing weed density, biomass and in
enhancing the weed control efficiency 40.9% and 38.0% during 2013 at 60 DAS. The
maximum rice grain, straw and biological yield was found with application of bispyribac +
azimsulfuron (25 g + 35 g/ha) + 0.25% NIS as post-emergence at 15-20 DAS and was
significantly superior over rest of the treatments during cropping period.