Tej PratapKailkhura, Siddhant2018-09-062018-09-062015-07http://krishikosh.egranth.ac.in/handle/1/5810072070A field experiment was conducted durig kharif season of 2014 in D2 block of N.E. Borlaug Crop Research Center of G. B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand) to evaluate “Herbicides combination for control of complex weed flora in transplanted rice (Oryza sativa L.)”. The experiment was aimed to find out the efficacy of different herbicides alone and in combination for weed control in transplanted rice. The soil of the experimental site was silty loam having high organic carbon (0.89%), low available nitrogen (244.6 kg/ha), medium available phosphorus (22.4 kg/ha) and available potassium (215.6 kg/ha). Rice variety “Narendra 359” was transplanted in the main field on June 27th 2014 and harvested on October 17th 2014. The experiment was laid out in a randomized block design with three replications to evaluate twelve treatments viz. bispyribac-sodium 25g/ha, penoxsulam 24% SC 22.5 g/ha, bispyribac-sodium 25 g/ha + ethoxysulfuron18.75 g/ha, bispyribac-sodium 25 g/ha + ready mix of chlorimuron ethyl and metsulfuron methyl 4 g/ha, pretilachlor 750 g/ha fb ethoxysulfuron 18.75 g/ha, pretilachlor 750 g/ha fb ready mix of chlorimuron ethyl and metsulfuron methyl 4 g/ha, pyrazosulfuron 20 g/ha fb readymix of chlorimuron ethyl and metsulfuron methyl 4 g/ha, ready mix mixture of penoxsulam + cyahalofop butyl 6% OD 135 g/ha, ready mix mixture of triafamone + ethoxysulfuron 60 g/ha, pendimethalin 750 g/ha fb bispyribac-sodium 25 g/ha, hand weeding at 25 and 45 DAT and weedy check. The major weed species in the experimental plot were Echinochloa colona, Echinochloa crus-galli, Leptochloa chinensis, Ischaemum rugosum, Panicum maximum, Caesulia axillaris, Ammania baccifera, Alternanthra sessilis, Cyperus iria and Cyperus difformis. Pretilachlor 750 g/ha fb ethoxysulfuron 18.75 g/ha was most effective in reducing the weed density and pendimethalin 750g/ha fb bispyribac-sodium 25 g/ha was most effective in minimizing the weed dry matter accumulation as compared to other treatments. The yield and yield attributing characters were influenced according to the effectiveness of the treatments. Pendimethalin 750g/ha fb bispyribac-sodium 25 g/ha recorded the highest grain yield followed by ready mix of penoxsulam + cyhalofop-butyl 135g/ha. Lowest grain yield was recorded under weedy check. The highest benefit cost ratio was recorded with penoxsulam + cyhalofop-butyl 135 g/ha which was closely followed by pendimethalin 750 g/ha fb bispyribac-sodium 25 g/ha. The results suggest that herbicidal combinations can be used as an alternative when labour is a limiting and costly factor in the cultivation of transplanted rice.ennullThesis