Yield and economics as influenced by nitrogen scheduling, weed management and rice establishment methods in transplanted rice (Oryza sativa)

A field experiment was conducted during the rainy (kharif) seasons of 2010 and 2011 at Varanasi, Uttar Pradesh, to evaluate the effect of nitrogen scheduling, riceestablishment methods and weed management on BPT 5204 rice (Oryza sativa L.) cultivar. The major group of weed species observed in the experimental field were grasses followed by broad-leaf weeds and sedges. Significant reduction in weed biomass was recorded in puddled transplanting as compared to unpuddled transplanting and in butachlor 1.50 kg/ha followed by cono- weeding at 20 days after transplanting (DAT) amongst the weed-management treatments. However, in the nitro- gen scheduling treatments, significantly lesser weed biomass was recorded in initial reduced dose and delayed ni- trogen application (one-fourth at 10 days, half at tillering stage and one-fourth at panicle-initiation stage) than con- ventional scheduling of nitrogen application (half at basal, one-fourth at tillering stage and one-fourth at panicle- initiation stage). Puddled transplanting resulted in significantly more grains/panicle, panicle length, panicles/hill, grain yield (t/ha), nitrogen uptake and nitrogen-use efficiency, net returns and benefit: cost ratio than unpuddled transplanting and in butachlor 1.5 kg/ha followed by cono-weeding at 20 DAT as compared to the other weed- management treatments. An initial reduced dose and delayed nitrogen application (one-fourth at 10 DAT, half at tillering stage and one-fourth at panicle-initiation stage) recorded significantly higher values of yield attributes, yields, net return and benefit: cost ratio than conventional scheduling of nitrogen application.