Performance of Bt cotton evaluated in relation to mulching and weed control measures in north-west India

Abstract

Abstract Weed infestation in cotton has been reported to offer severe competition and causing yield reduction to a large extent. Weeding via cultural practices is time consuming, tedious and expensive due to long duration of cotton crop and regular monsoon rains. Chemical weed control in cotton has been successfully utilized in the recent past. However, continuous use of similar herbicides leads to resistance in weeds against herbicides and when sprayed to the field herbicides not only suppress the weeds that are targeted but they can leave undesirable residues in the soil that are hazardous to environment. Therefore, a study was performed at cotton research area, Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana during two consecutive kharif season (2020 and 2021). The experiment was laid out in factorial randomized block design with two mulching levels (No mulch and Mulching with rice straw @ 7.5 t/ha) and seven weed management levels [Weedy check, Weed free, pendimethalin (PRE) 1.5 kg/ha fb two hoeing at 45 and 90 DAS, Two hoeing at 30 and 60 DAS fb quizalofop-p-ethyl 62.5 g/ha at 90 DAS, Two hoeing at 30 and 60 DAS fb propquizafop-p-ethyl 50 g/ha at 90 DAS, pendimethalin (PRE) 1.5 kg/ha fb one hoeing 45 DAS fb paraquat 0.5% (protected spray) at 90 DAS and pendimethalin (PRE) 1.5 kg/ha fb one hoeing 45 DAS fb glyphosate 1% (protected spray) at 90 DAS] with three replications. Mulching with rice straw @7.5 t/ha resulted in significantly higher seed cotton yield (3189 and 3084 kg/ha) and better weed control in comparison to no mulch (2990 and 3189 kg/ha) in 2020 and 2021 respectively. Among weed management levels apart from weed free, significantly lowest seed cotton yield (1841 and 1757 kg/ha) recorded in weedy check in comparison to other treatments while all other treatments were statistically at par with each other during both years of crop experimentation respectively. Herbicide efficiency index (7.13 and 7.31) achieved with application of pendimethalin (PRE) @1.5 kg/ha fb one hoeing at 45 DAS fb glyphosate 1% (protected spray) at 90 DAS during kharif 2020 and 2021 respectively