Weed dynamics and growth of soybean in response to different sowing dates and weed management treatments under rainfed conditions of Nagaland

AbstractAn experiment was conducted at the School of Agricultural Sciences, Medziphema Campus, Nagaland University, Nagaland, India, during the Kharif seasons of 2021 and 2022. The objective was to examine the weed dynamics and the growth of soybean (Glycine max (L.) Merill) in response to different sowing dates and weed management treatments. A split-plot design was employed, with three sowing dates in the main plots and seven integrated weed management treatments in the sub-plots. The pooled results over the two years indicated that soybean sown on June 15 exhibited significantly lower total weed density and biomass and higher weed control efficiency. The June 15 sowing date also resulted in maximum soybean plant height, branches per plant, dry matter production, leaf area index, number of nodules, dry weight of nodules, seed yield and stover yield. Among the herbicide treatments, the sequential treatment of pre-emergence application (PE) pendimethalin 1000 g/ha followed by (fb) post-emergence application (PoE) of imazethapyr 100 g/ha at 20 days after sowing (DAS) recorded lower weed density, weed biomass, higher weed control efficiency with enhanced growth attributes and yield of soybean. It was concluded that early sowing (on June 15) and application of pendimethalin 1000 g/ha PE fb imazethapyr 100 g/ha PoE at 20 DAS, resulted in significant control of weeds and increased growth and yield of soybean.