Comparison of UAV and knapsack herbicide application methods on weed spectrum, crop growth and yield in dry direct-seeded rice

A field experiment was conducted to compare the Unmanned Aerial Vehicle (UAV) and knapsack herbicide application on the diverse weed flora, growth and yield attributes of dry-direct seeded rice in randomized block design replicated thrice during 2023 at Pandit Jawaharlal Nehru College of Agriculture & Research Institute, Karaikal, Puducherry UT, India. Grasses dominated the weed flora, with 80.5% relative density of Echinochloa colona. UAV spray volume at 50 L/ha with application of pendimethalin + penoxsulam on 3 DAS 625 g/ha fb bispyribac-sodium on 20 DAS 25 g/ha reduced total weed density (39.4/m²) and biomass (23.4 g/m²), resulted better rice growth (plant height and tillers/plant), yield parameters (panicle weight and 1000 grain weight) and yield (3.87 t/ha). Negative linear relationship was observed between rice grain yield and total weed biomass at harvest stage. Uncontrolled weeds caused 65.6% yield loss in dry-DSR of the coastal deltaic ecosystem.