Impact of Chemical Weed Management Practices on Yield, Nutrient Uptake and Balance in Soil of High Density Planting Cotton in Deep Vertisols

In order to assess Clomazone 50 EC's effectiveness on seed cotton yield, nutrient uptake, and balance in HDPS cotton in deep Vertisols of the Northern Karnataka region, a field experiment was carried out in 2017–18 and 2018–19. The recommended course of treatment includes pre-emergence applications of Clomazone 50 EC at 250, 500, and 750 g a.i./ha compared to pendimethalin 37.5 CS@680 g a.i./ha, post-emergence applications of pyrithiobac sodium 10 EC and quizalofop ethyl hand weeding at 25 DAS and intercultivation at 50 and 75 days after sowing, as well as weed free. The experiment was set up using a randomised block design with triple replication. The application of Clomazone 50 EC @ 250 g a.i./ha was found to be effective in weed control and enhanced seed cotton yield (38.5%), according to the results. It led to excellent weed control, decreased nitrogen uptake by weeds, and increased nutrient uptake by the crop. Additionally, it leads to the least amount of nutrient losses in terms of uptake and losses. In order to effectively manage weeds in cotton, it was observed that Clomazone 50 EC @ 250 g a.i/ha, followed by pyrithiobac sodium 10 EC @ 75 g a.i./ha + Quizalofop ethyl 5 EC @ 75 g a.i./ha at 25 DAS, were the best applications.