Effect of first irrigation scheduling and herbicides on productivity of direct-seeded rice (Oryza sativa)

An experiment was conducted during the rainy (kharif) season of 2019 at Students’ Research Farm, Khalsa College, Guru Nanak Dev University, Amritsar, Punjab. First irrigation timings, viz. I₁, 7 days after sowing (DAS); I₂, 14 DAS and I₃, 21 DAS, as main plot and herbicidal combinations, viz. W₁, pendimethalin 750 g/ha + bispyribac 25 g/ha at 25 DAS; W₂, pendimethalin 750 g/ha + pyrazosulfuron 20 g/ha; W₃, pendimethalin 750 g/ha + pyrazosulfuron 20 g/ha + bispyribac 25 g/ha at 25 DAS; W₄, weedy check and W₅, weed-free as subplot treatments were conducted in a split-plot design with 3 replications. The results showed that, among the first irrigation scheduling, crop-growth parameters (plant height, dry-matter accumulation, leaf-area index); yield attributes (effective tillers, grains/panicle, 1,000-grain weight); grain yield (53.9 q/ha); net returns (₹71,326/ha) and benefit: cost (B: C) ratio (2.69) were maximum in I₁ treatment. Among the herbicidal combinations, crop-growth parameters, yield-attributing characters, grain yield (57.2 q/ha), net returns (₹ 79,800/ha), B: C ratio (3.18) and weed-control efficiency were recorded highest in pendimethalin 750 g/ha + pyrazosulfuron 20 g/ha + bispyribac 25 g/ha at 25 DAS. Inclusion of bispyribac with other herbicides performed better in direct-seeded rice.