Efficiency of pre and post-emergence herbicides to control weeds and enhancing yield of wheat (Triticum aestivum) in North-East India

A field experiment was conducted in rabi season during 2021 – 22 and 2022 – 23 at Tokowbari research farm of Assam Agricultural University-Zonal Research Station, Shillongani, Nagaon, Assam to find out a suitable and economically viable herbicide alone or in combination to control weeds as well as to increase productivity of wheat (Triticum aestivum L.). The effect of herbicides on weeds were analyzed by different indices such as Weed Control Efficiency (67.10), Treatment Efficiency Index (2.02), Crop Resistant Index (4.00) were highest and Weed Persistant Index (0.84) were lowest with pre-emergence tank mix application of Pyroxasulfone + metribuzin@ 127.5 + 280 g a.i./ha (T₁₀) and Weed Index was highest in T₁₁(Weedy check). Likewise significantly highest grain yield (32.99 q/ha) were recorded in case of weed free treatment (T₁₂) followed by 31.12 q/ha with pre-emergence tank mix application of Pyroxasulfone + metribuzin@ 127.5 + 280 g a.i./ha (T₁₀) which was at par (30.83 q/ha) with Pre-emergence tank mix application of Pendimethalin + metribuzin@1250 + 280 g a.i./ha (T₉). But the highest B:C (2.39) ratio was achieved in T₄ (pre-emergence tank mix application of Pendimethallin + Pyroxasulfone @ 1250 + 127.5 g a.i./ha) followed by T₇ (EPOST tank mix application of Pyroxasulfone + metsulfuron@ 127.5 + 4 g a.i./ha).