Growth and Yield Response of Spring Sunflower to Weed Competition Periods and Control Methods

Weed infestation severely reduces sunflower growth and yield. A field experiment was conducted using a split-plot RCBD with weed control methods (manual and chemical) as main plots and weeding times (weed-free, 10, 20, 30, 40, 50 days after emergence, and weedy check) as subplots. Significant differences were observed for weed density, biomass, growth, and yield traits. Maximum achene yield (2774.3 kg ha⁻¹) and net return (Rs 1.69 ha⁻¹) were recorded in weed-free treatment under manual control, followed by manual weeding at 30 days after emergence. Chemical control also produced higher returns compared with the weedy check. Overall, timely and effective weed management substantially improved sunflower productivity and profitability under spring planting conditions.