Herbicides combinations for control of complex weed flora in transplantedrice in Lateritic belt of West Bengal

摘要

Rice (Oryza sativa L.) is one of the world's most important food crops (Singh and Khush 2000). Currently more than half of the world's population depends on rice for food, calories and protein, especially in developing countries. Rice is the world's most important food among all staple food crops and more than half of the world's population depends on rice for food, calories and protein, especially in developing countries. It is grown by manual transplanting of seedlings into puddled soil. Like othercereal crops, rice also suffers severely from weed competitions (Rao et al. 2007). Uncontrolled weeds compete with rice and cause yield losses to the tune of 50-65% under wet-seeded rice (Subbaiah and Sreedevi 2000) and up to 76% in transplanted rice (Singh et al. 2004). The farmers generally do hand weedings in transplanted rice. Post-emergence application of metsulfuron-methyl + chlorimuron-ethyl and early post-emergence application of ehoxysulfuron showed promising results in achieving more grain yield of transplanted rice (Pal et al. 2008). Pre-emergence application of pyrazosulfuron, penoxsulam (Chauhan and Seth 2013) and post-emergence bispyribac (Khaliq et al. 2012) herbicides were considered to be an alternative/supplement to hand weeding. Therefore, the present experiment was conducted to find out the effective herbicides or herbicide mixtures for weed control in transplanted rice.The field trial was laid out in RBD with 12 treatments and replicated thrice in Agricultural Farm of Visva-Bharati during Kharif, 2014. The herbicide treatments were bispyribac-Na 25 g/ha and penoxsulam 22.5 g/ha alone, tank-mix of bispyribac-Na 25 g/hawith ethoxysulfuron 18.75 g/ha and (chlorimuron + metsulfuron ) 4 g/ha, pretilachlor 750 g/ha followed by (fb) ethoxysulfuron 18.75 g/ha and (chlorimuron + metsulfuron ) 4 g/ha, pyrazosulfuron 20 g/ha fb (chlorimuron + metsulfuron ) 4 g/ha, ready mix ofpenoxsulam + cyhalofop 135 g/ha, ready mix of triafamone + ethoxysulfuron 60 g/ha andpendimethalin 750 g/ha fb bispyribac 25 g/ha. Two hand weeding and weedy check were also included. Herbicides were applied with knapsack sprayer fitted with flat fan nozzle using 500 L/ha of water. The rice (var. TR-36') was transplanted on 26th August,2014 and harvested on lllh November 2014. . The weed population, biomass of weed, yield attributes and yield were recorded. The weed population and biomass of weeds were subjected to square-root transformation (v.v + o.s). The data were analyzed according to randomized block design by standard ANOVA at p=0.05 level of significance.