Efficiency of coated-urea materials in rice (Oryza sativa) - wheat (Triticum aestivum) system under partially reclaimed sodic soil

In a field experiment in partially reclaimed sodic soil different coated-ur ea materials, viz gypsum-coated urea, coaltar-coated urea, sulphur-coated u rea at 3 levels of N, viz 40, 80 and 120 kg/ha were compared with the prill ed urea under rice (Oryza sativa L.) - wheat (Triticum aestivum L. emend. F iori & Paol.) cropping system. Among coated-urea materials neem cake-coated urea and sulphur-coated urea were at par and significantly superior to the prilled urea with respect to the yield, yield attributes and N uptake and its recovery in rice-wheat system. However, maximum values of all these par ameters were recorded with neem cake-coated urea. Grain yield of both the c rops at 80 kg N/ha as neem cake-coated urea and sulphur-coated urea were at par with those obtained with prilled urea at 120 kg N/ha. Average recovery of applied N with neem cake-coated urea was 32.1 and 37.5% in rice and whe at crops as against 20.5 ana 27.1% with prilled urea respectively. Neem cak e-coated urea followed by sulphur-coated urea also maintained higher concen trations of NH4+-N in soil under rice and NH4+-N and NO3--N under wheat tha n prilled urea throughout the crop growth.