Efficacy of slow release N-fertilizers for rice and their residual effect on wheat

A field experiment was conducted during 1989-91 on sandy clay loam soil at Ranchi to study the efficiency of forms of urea viz, prilled (PU), lac coat ed (LCU), rock phosphate coated (RCU), karanj cake coated (KCU) and neem ca ke coated (NCU) at varying N rates (40, 80, 120 kg/ha) on the productivity of rice and their residual effect on succeeding wheat. LCU had markedly hig her grain yield of rice than other forms of urea. Each incremental N level recorded higher grain yield over its preceding level. However, nitrogen use efficiency decreased with increasing N levels. Application of LCU and NCU had higher soil available N after rice as compared with other forms of urea . This was reflected on the productivity of succeeding wheat. Rice fertiliz ed with 120 kg N/ha also recorded the maximum grain yield of succeeding whe at.