Abstract

A field experiment was carried out at Norman E. Borlaug Crop Research Centre of G. B. P. U. A. & T., Pantnagar, U. S. Nagar, Uttarakhand during kharif seasons of 2014 and 2015 to evaluate the efficacy of different herbicides and their combinations to control the different weed flora in transplanted rice. The experimental site was silty clay loam in texture, medium in organic carbon (0.66%), available phosphorus (27.5 kg/ha) and potassium (243.5 kg/ha) with pH of 7.3. The experiment was laid out in randomized block design with 12 treatments replicated thrice. In the present study, Echinochloa colona, Echinochloa crus galli, Leptochloa chinensis, Ammania baccifera, Caesulia axillaris, Cyperus iria and Cyperus difformis were found as major weeds in experimental field during both the years. The results revealed that among the herbicidal treatments penoxsulam+cyahalofop-butyl @ 135 g/ha recorded lowest total weed density which was statistically similiar to pretilachlor @ 750 g/ha fb ethoxysulfuron @ 18.75 g/ha, bispyribac-sodium+ethoxysulfuron @ 25+18.75 g/ha, pretilachlor @ 750 g/ha fb readymix of chlorimuron-ethyl +metsulfuron-methyl @ 4 g/ha and pendimethalin @ 1000 g/ha fb bispyribac-sodium @ 25 g/ha. The total weed dry weight was significantly reduced with penoxsulam+cyahalofop-butyl @ 135 g/ha, pendimethalin @ 1000 g/ha fb bispyribac-sodium @ 25 g/ha and pretilachlor @ 750 g/ha fb ethoxysulfuron @ 18.75 g/ha over rest of the herbicidal treatments. The highest weed control efficiency (98.2%) was also recorded with readymix of penoxsulam+cyahalofop-butyl @ 135 g/ha followed by pendimethalin @1000 g/ha fb bispyribac-sodium 25 g/ha, pretilachlor 750 g/ha fb ethoxysulfuron 18.75 g/ha, bispyribac-sodium+ethoxysulfuron @ 25+18.75 g/ha. The maximum grain yield (6.8 t/ha) was recorded with penoxsulam+cyahalofop-butyl @ 135 g/ha which was statistically at par with pendimethalin @ 1000 g/ha fb bispyribacsodium @ 25 g/ha, twice hand weeding at 25 and 45 DAT, bispyribac-sodium+ethoxysulfuron @ 25+18.75 g/ha, pretilachlor @ 750 g/ha fb ethoxysulfuron @ 18.75 g/ha and readymix of triafamone+ethoxysulfuron @ 60 g/ha.