Performance of rice ( Oryza Sativa L.) cultivars to integrated application of fertilizer n and farmyard manure in acid laterite soil

Varietal adaptability in exploiting the natural resources is important. Field experiments were conducted during the wet seasons of 1998 and 1999 at the Regional Research Substation, Sekhampur. The aim was to evaluate the performance of locally popular IR-36 (high yielding, photo-insensitive) and Khejurthari (local land race, photosensitive) rice cultivars with variable proportions of N management through inorganic and organic supplements separately or combined. The cv. IR-36 produced the highest number of panicles/m 2 but the cv. Khejurthari had significantly higher number of grains/panicle and test weight. Fertilizer N and farmyard manure rates influenced the yield attributing characters. The cv. IR-36 produced 10% more grain yield than Khejurthari. Combined application of inorganic (urea) and organic (farmyard manure) sources increased the grain yield by 72% over no input (control). Nitrogen uptake by cv. IR-36 and Khejurthari was statistically similar. Application of 60 kg N/ha with 4 t farmyard manure/ha increased the N uptake by 1.88 times compared to control. Apparent N recovery was higher in cv. IR-36 at higher doses of N and in cv. Kejurthari at lower doses.