WEED MANAGEMENT IN AEROBIC RICE: ROLE OF ESTABLISHMENT METHODS AND HERBICIDES

Weed management in rice depends on establishment method and proper selection of herbicide. A field experiment was conducted during dry seasons of 2013 and 2014 to develop a robust strategy for effective weed management in aerobic rice system for tropical rice belts. The efficacy of post-emergent herbicides bispyribac-sodium, azimsulfuron and flucetosulfuron were evaluated under different rice establishment methods (row sowing, spot seeding and broadcasting). Grass weed species constituted 58-68% of the total weed density across the establishment methods in the weedy check treatment. The total weed density and weed biomass were lowest in spot seeding with azimsulfuron (35 g active ingredient (a.i.) ha(-1)) 30 and 60 days after sowing. Among herbicides, use of azimsulfuron caused the highest grain yield (5.2 Mg ha(-1)), realizing 72% increase in grain yield over the weedy check. Yields in row sowing and spot seeding were similar and the same was verified when comparing yields in plots treated with bispyribac-sodium and azimsulfuron. Based on our findings and considering both weed presence and grain yield, azimsulfuron in spot seeding can be recommended in aerobic rice.