Efficacy of Different Herbicides for Weed Control in Transplanted Rice (Oryza sativa. L) Under Vertisols of Rajasthan

The study was carried out during kharif season of 2007 and 2008 at the Agricultural Research Station, Ummedganj, Kota (Rajasthan). The experiment was laid out in randomized block design with tweleve treatments replicated fourtimes. The major weeds observed in the experimental plots included grasses Echinochloa colonum and Echinochloa crusgalli sedges like Cyperusrotundus, Cyperusdifformis and Cyperus iria and broad leaf weeds Eclipta alba, Euphorbia hirta L, Commelina diffusa and Ammania baccifera. Among the herbicides tested, Pretilachlor 50 EC @ 0.750 kg a.i.ha⁻¹ at 3–5 days after transplanting registered significantly lowest weed density (16 & 15), weed dry weight (29.34 & 22.10 g m⁻²) at 60 DAT over other herbicidal treatments, leading to highest weed control efficiency of 79.73 and 90.23% and lowest weed index value of (3.95 and 14.52) and highest herbicidal efficiency index (1.82 and 2.21), higher number of panicles m⁻² (381 and 278), panicle weight (3.70 and 3.80 g), grain (4.96 and 4.23 tha⁻¹) and straw yield (6.61 and 5.81 t ha⁻¹) in 2007 and 2008, respectively. The per cent increase in grain yield was 34.78 and 42.42 with the application of pretilachlor 50 EC @ 0.750 kg a.i. ha⁻¹ at 3–5 days after transplanting over non weeded control in 2007 and 2008, respectively