Effect of glufosinate-ammonium on weeds, cotton yield and soil microbes

The present study evaluated the response of weeds and cotton to different weed management treatments. The weeds predominant in the experimental field were: Echinochloa crus-galli, Echinochloa colona, Digera arvensis, Amaranthus viridis and Cyperus rotundus. The monocot weeds increased from 48.50% at 25 days after seeding (DAS) to 55.42% at 50 DAS, while dicot weeds increased to 47.00% during that period, probably due to crop growth and canopy development. The weed-free treatment [hand weeding (HW) thrice + inter cultivation (IC) at 20, 40 and 60 DAS] recorded the highest weed control efficiency (WCE) (84.70%) and seed cotton yield. The weedy check recorded cotton yield reduction of 46.53%. Pendimethalin 0.9 kg/ha followed by (fb) quizalofop-ethyl + pyrithiobac-sodium 50 + 75 g/ha and glufosinate-ammonium 350–450 g/ha combined with hand weeding and inter-cultivation at 50 DAS, effectively managed weeds recording weed control efficiency of 71.15-78.90% and cotton yield of 2.158 t/ha. Glufosinate-ammonium applied alone exhibited lower weed control efficacy (41.41-45.49%) and lesser cotton yield. Soil microbial populations showed transient suppression following herbicide application but recovered by 60 days after application indicating short-term and reversible effects. Overall, integrated weed management proved most effective in managing diverse weed flora and recording higher cotton yield.