Relative performance of neem coated urea on the basis of need based nitrogen management using customized leaf colour chart in low land rice (Oryza sativa) of eastern India

An experiment was conducted during the Kharif season, of 2018 to study the effect of NCU in conventional and customized leaf colour chart (CLCC) based approach on rice (Oryza sativa). The eight treatments were evaluated in randomized block design with three replications. It has been found that application of NCU based on CLCC recorded higher yield i.e. by 7.74% in comparison with conventionally applied NCU and 12.5% in comparison with conventionally applied OU. The N2O emission ranged from 14.1–91.6 μg N2O-N m−2 hr−1 and the total N2O-N emission during the season ranged from 0.38 to 0.61 kg ha−1. The loss of N through N2O emission was recorded in the range of 19-23% under NCU applied based on CLCC than those applied under conventionally. 75% RDN in form of NCU based on CLCC recorded the highest N recovery efficiency (REN) (49.62%). CLCC based NCU application recorded notable performance in most of the yield attributing characters such as number of panicles m-2, panicle length, number of grains panicle-1, number of filled grains panicle-1 and harvest index. It also recorded the highest yield (4.59 t ha-1) amongst all the treatments and increases the yield by 7.74% in comparison with conventionally. The results acknowledged that N can be saved by following CLCC approach.