Effect of planting time and nitrogen on production potential of basmati rice (Oryza sativa) cultivars in Bihar plateau

A field experiment was conducted during rainy season of 1996-97 on clay-loa m Soil: at Ranchi to study the effect of transplanting time (7 and 22 July) and nitrogen levels (60, 80 and 100 kg/ha) on production potential and pro fitability of scented rice (Oryza sativa L.) cultivars ('Sugandha', 'Basmat i 370', 'Pusa Basmati 1' and 'BR 10'), A split-plot design was followed: ke eping transplanting time in main plot and combinations of varieties and nit rogen levers in subplot; with 3 replications. Timely transplanted (7 July) crop gave 17.2, 18.7, 18.8 and 14.4% higher grain yield, net return, net be nefit : cost ratio and monetary productivity than late-planted crop (2,225 kg/ha, Rs 18,319/ha net return, 3.41 net benefit : cost ratio and Rs 136.7/ ha/day monetary productivity). Rice variety 'Pusa Basmati 1' gave significa ntly higher grain yield (2,930 kg/ha) with physical productivity (21.7 kg/h a/day), net return (Rs 24,372/ha), net benefit: cost ratio (4.54) and monet ary productivity (Rs 180.53/ha/day) than the remaining. Each incremental le vel of nitrogen gave significantly higher grain yield over its preceding le vel; and maximum grain yield (2,647 kg/ha), physical productivity (19.94 kg /ha/day), net return (Rs 24,372/ha), net benefit : cost ratio (4.54) and mo netary productivity (Rs 180.53/ha/day), net return (Rs 22,536/ha) net benef it : cost ratio (4.07) and monetary productivity (Rs 162.13/ha/day) were ob tained at 100 kg N/ha. Rice 'Pusa Basmati 1' and 'Sugandha' responded up to 100 kg N/ha, whereas 'Basmati 370' and 'BR 10' responded only up to 80 and SO kg/ha respectively.