Herbicidal weed-management options for dry direct-seeded rice (Oryza sativa) in North-Eastern Plains of India

A field experiment was conducted during the rainy (kharif) seasons of 2017 and 2018 at Regional Station of the ICAR-Indian Agricultural Research Institute, Pusa, Samastipur, Bihar, to study the effect of herbicides in controlling mixed weed flora in direct-seeded rice (Oryza sativa L.). The experimental results revealed that, the alone and sequential application of herbicides significantly reduced the weed density and biomass of complex weed flora. The growth and yield attributes, viz. plant height at maturity, effective tillers/m², 1,000grain weight, grains/panicle and panicle length, were significantly influenced by application of herbicides. Weed-free condition resulted in significantly highest grain yield (4.49 t/ha). Among different herbicidal treatments, application of pendimethalin @ 1,000 ml/ha followed by (fb) tank-mix application of bispyribac sodium (25 g/ha) + pyrazosulfuron (15 g/ha) resulted in higher plant height (110.7 cm), higher number of effective tillers (320.0/m²), grains/panicle (132.2), ear length (29.8 cm), grain yield (4.49 t/ha), net returns (₹ 70,600/ha) and benefit: cost ratio (1.67), which was superior to rest of the treatments. Application of pendimethalin (1,000 ml/ha) fb tank-mix application of bispyribac sodium (25 g/ha) + pyrazosulfuron (15 g/ha) significantly reduced the weed density (56.8/m²) and weed biomass (26.6 g/m²).