Effect of different doses of prilled urea and urea supergranule on volatilisation loss of ammonia and nitrogen use efficiency in rice

摘要

The nitrogen use efficiency by rice and volatilisation loss of ammonia from rice field were studied following application of prilled urea (PU) and urea supergranule (USG) at two different doses i.e. 76 kg N ha~(-1) and 114 kg N ha~(-1) in a field experiment conducted on a Typic Haplaquept. Application of USG @ 76 kg N ha~(-1) was adjudged to be the best source of fertiliser N for rice. Deep placement of USG significantly improved grain yield, straw yield and nitrogen use efficiency by rice and reduced the volatilisation loss of ammonia from rice field than broadcasting of prilled urea. ~(15)N balance study revealed that fertiliser N recovery by the second rice crop (3.83-6.50%) was considerably lower than the first rice crop (24.22-36.96%) in a rice-rice cropping sequence. The contribution of fertiliser N towards the volatilisation loss of ammonia was found to be dwindling with the progress of time following the application of ~(15)N labelled urea.