Assessment of herbicide-induced changes in beneficial microflora of Bajra (Pennisetum glaucum L.) rhizosphere

The present study investigates the impact of various herbicides on beneficial microbial populations in the rhizosphere of Pennisetum glaucum (Bajra), focusing on Azotobacter, Azospirillum, and phosphate-solubilizing bacteria (PSB). Herbicidal treatments significantly influenced microbial populations at different crop growth stages, with a peak observed at 60 days after sowing (DAS). Among pre-emergence herbicides, Pendimethalin consistently supported the highest populations of all three microbial groups, while Oxyfluorfen exhibited suppressive effects. Phenaxoprop-ethyl emerged as the most favorable post-emergence herbicide, enhancing microbial proliferation, whereas Imazethapyr consistently reduced microbial abundance. Sequential application of Pendimethalin + Propaquizafop-ethyl maintained the highest microbial populations, while the combination with Imazethapyr was the least favorable. Microbial populations declined slightly by harvest, though treatment trends remained consistent. The findings highlight Pendimethalin and Phenaxoprop-ethyl as microbiologically compatible options, while Imazethapyr poses potential risks to rhizospheric health. These results emphasize the importance of selecting herbicides not only for weed management efficacy but also for their compatibility with beneficial soil microflora crucial for nutrient cycling and plant productivity. The study underscores the ecological benefits of integrating herbicide strategies with microbial sustainability, recommending Pendimethalin + Propaquizafop-ethyl for promoting rhizospheric microbial health in sustainable bajra cultivation.