Post-Emergence Chemical Weed Control in Direct Seeded Rice (Oryza sativa L.) in New Alluvial Zone of West Bengal

Direct seeded rice (DSR) seems to be a viable option under erratic rainfall and water scarcity. Despite several advantages of DSR, weeds are the major biological constraint. Afield experiment was conducted at Central Research Farm, Gayeshpur of Bidhan Chandra Krishi Vishwavidyalaya Mohanpur, Nadia, West Bengal during the kharif season ((July- November) of 2020 and 2021, comprisingnine weed control methods viz. T1- Imazethapyr 10% SL @ 1000 ml ha-1at 15 DAS, T2 - Imazethapyr 10% SL @ 1250 ml ha-1at 15 DAS ,T3- Imazethapyr 10% SL @ 2000 ml ha-1at 15 DAS, T4- Imazethapyr 10% SL @ 750 fb 750 ml ha-1at 15 DAS and 30 DAS, T5- Imazethapyr 10% SL @ 1000 fb 1000 ml ha-1at 15 DAS and 30 DAS, T6- Imazethapyr 10% SL @ 1250 fb 1250 ml ha-1at 15 DAS and 30 DAS, and T7- Imazethapyr 10% SL @ 2000 fb 2000 ml ha-1at 15 DAS and 30 DAS, T8- weed free check (2 times hand weeding at 20 DAS and 40 DAS) and T9- un-treated control (weedy check) along with 3 replicationslaid out in RBD design in herbicide tolerant rice variety Sava 134 was conducted during two consecutive kharif season of 2020 and 2021 at Central Research Farm, Gayeshpur, B.C.K.V., Nadia under new alluvial zone of West Bengal. The experimental results revealed that maximum grain and straw (4.20 and 4.36 t per ha), as well as net return (Rs. 44546per ha) were recorded in double hand weeding (T8), which was at par with Imazethapyr treated plots like T5, T6 and T7. Thus the tedious, time-consuming, and costly hand-weeding can be profitably replaced by the application of Imazethapyr 10% SL @ 1000 fb 1000 ml per ha at 15 and 30 DAS. This weed control methodhas satisfactory performance in DSR exhibiting higher weed control efficiency and no phytotoxicity symptoms to the herbicide tolerant rice crop and increased both grain and straw yields vis-à-vis benefit : cost ratio.