Herbicide combinations and nitrogen scheduling for weed management andyield improvement in transplanted rice

摘要

Field experiment was conducted during rainy seasons of 2018 and 2019 to evaluate the efficacy of herbicide mixtures and nitrogen application scheduling to control grasses, sedges and broad-leaved weeds in transplanted rice. Posl-emergence applicationof triafamone 20 + ethoxysulfuron 10 (ready-mix) 67.5 g/ha at 20 days after transplanting (DAT) was found comparable with two rounds of hand weeding at 20 and 40 DAT in controlling all categories of weeds. Among different nitrogen application schedules, application of 25 N at 10 DAT + 50 N at active tillering (AT) + 25 N at panicle initiation (PI) recorded higher weed control efficiency (73.4) and grain yield (6.3 t/ha) of rice as compared to the recommended schedule of 25 N as basal + 50 N at AT + 25 N at PI (WCE of 66.9 and grain yield of 5.7 t/ha). Triafamone 20 + ethoxysulfuron 10 (ready-mix) 67.5 g/ha at 20 DAT recorded 81.7 WCE, improved crop growth and yield attributes and consequently increased grain yield (6.0 t/ha) as well as netreturn (69360 t/ha) as compared to fenoxaprop-p-ethyl 9 EC 56.2 g/ha + ethoxysulfuron 15 WDG 18.7 g/ha (tank-mix) at 20 DAT. Tank-mix application of fenoxaprop-p-ethyl + ethoxysulfuron caused yellowing of rice leaves although it disappeared within 20 days after application, whereas no such phytotoxicity was recorded under ready-mix application of triafamone + ethoxysulfuron.