Evaluation of Low Dose Herbicides in Transplanted Rice (Oryza Sativa L.).

ABSTRACT

A field experiment was conducted during kharif 2011 at College of Agriculture, Rajendranagar. The experiment consisted of 12 treatments laid out in randomized block design with three replications consisting of two pre-emergence herbicides integrated with post emergence herbicides and one hand weeding at 40DAT and two post emergence herbicide, hand weeding twice at 20 and 40 days after transplanting, compared with weed free and unweeded check. The predominant weed flora observed in the experimental field were Echinochloa crusgalli, Panicum repens, Cynodon dactylon, Cyperus rotundus, Cyperus difformis, Eclipta alba and Ammania baccifera. The results revealed that pre-emergence application of Bensulfuron methyl 0.6% + Pretilachlor 6% @ 10 kg granules ha- 1+ Hand weeding at 40 DAT (5455 kg ha-1 and 6345 kg ha-1) and Bensulfuron-methyl 0.6% + Pretilachlor 6% @ 10 kg granules ha-1 + Bispyribac sodium @ 25 g a.i ha-1 recorded significantly higher grain and straw yield (5365 and 6265kg ha-1, respectively) which remained at par with two hand weedings at 20 and 40 DAT (5580 and 6464 kg ha- 1). In terms of economics, highest net returns (Rs. 33,189 ha-1) and BC ratio (1.40) were also high with the preemergence application of Bensulfuron-methyl 0.6%+ Pretilachlor 6% @ 10 kg granules ha-1+ Bispyribac sodium @ 25 g a.i. ha-1 at 20DAT (1.40) compared to that of two hand weedingds (Rs. 31,952 ha-1) and benefit cost ratio (1.17) .