Weed Control and Yield Performance of Direct-Seeded Rice with Varying Rates of Post-Emergence Herbicides.

Weeds are serious pests in rice sown under direct-seeded rice (DSR) technology. Herbicide-based weed management is becoming increasingly popular, but there is a dire need to choose appropriate herbicides and their effective dose for controlling weeds in DSR fields. A field trial was conducted to appraise the comparative efficacy of three post-emergent herbicides applied at different doses [Clover 20% EC (bispyribac sodium) at 39.54, 59.30, and 79.07 g a.i. ha-1, Pyranex Gold 30% WDG (bispyribac sodium + bensulfuron methyl) at 74.13, 111.20, and 148.26 g a.i. ha-1, and Puma Super 7.5% EW (fenoxaprop-p-ethyl) at 46.33 and 92.66 g a.i. ha-1] at 20 days after sowing (DAS) for weed control and paddy yield performance under DSR system. A weedy check was retained as control. Results revealed that Clover and Pyranex Gold applied at either dose significantly (p≤0.05) reduced the population and growth of Cyperus iria (90-97% weed density and 93-97% weed dry biomass) and Echinochloa colona (94-97% weed density and weed dry biomass) weeds over control, while Puma Super proved efficient in suppressing Leptochloa chinensis and Echinochloa colona weeds. Among all the tested treatments, application of Puma Super at 92.66 g a.i. ha-1 furnished the highest number of tillers (137.3 in 2014 and 141.3 in 2015), grains panicle-1 (77 in 2014 and 79 in 2015), final paddy yield (1983.8 and 1570 kg ha-1 in 2014 and 2015, respectively), and net economic returns (Rs. 95915 ha-1), followed by the use of Puma Super at 46.33 g a.i. ha-1 which offered the next best economic benefits (Rs. 81906 ha-1). Thus, applying Puma Super at 92.66 g a.i. ha-1 is appeared viable approach to control grassy weed flora and ensure higher paddy yield with higher economic returns when rice is sown under DSR technology. [ABSTRACT FROM AUTHOR]