Influence of nitrogen and weed-management practices on crop-growth indices and productivity of dry direct-seeded rice (Oryza sativa)

A field study was carried out during the rainy (kharif) season of 2019–20 at ICAR-Indian Agricultural Research Institute, New Delhi, to effect nitrogen and weed management practices in dry direct-seeded rice (Oryza sativa L.) for obtaining higher productivity crop growth. The experiment laid a split-plot design, taking 3 treatments, i.e. No N (P K only), recommended dose fertilizer (RDF–N : P = 80 17 33 kg/ha) (3 splits application–50% basal + 25% tillering panicle-initiation stage), 50% from FYM as real-time (top-dressing) per leaf colour chart (LCC) up stage main plots. Four weed-management viz. unweeded control, weed-free Pendimethalin @ 1.5 kg a.i./ha pre-emergence followed by (fb) brown manuring with Sesbania bispinosa (Jacq.) W. Wight; Syn. S. aculeata [(Willd.) Pers.] (knocking down Bispyribac- Na 25 g days after sowing (DAS), fb Bispyribac -Na DAS subplots replications. Result revealed that, significantly increased grain yield (2.78 t/ha) well growth indices like leaf-area index (1.8 4.4 40 70 DAS, respectively), crop-growth rate (1.9 g/m2 /day, 8.8 /day relative (145.3 mg/g/day 54.5 net assimilation (0.40 3.49 g/m2/day respectively) dry-matter accumulation (185.6 , 591.6 1,144 harvesting, other treatments. In case N-management practices, combined use LCC-based gave highest (3.25 t/ha), (1.69 4.0 g/m2/day, 8.2 (145.1 55.1 (168.5 523.2 958 comparable RDF application than plot without N.