An executed laboratory study gauged the effect of slow-release fertilizers on nitrate leaching and its distribution in the soil profile and yield of wheat (Triticum aestivum L.). A comparison between numbers of coating layers (1, 2, and 3 layers) of neem oil on urea granules caused an investigation, with different parameters monitored. Results revealed a higher nitrogen (N) release arose from a single coating than the double and triple coatings at the early stage of fertilizer application, indicating a poor performance and less efficiency. Triple coating effectively suppressed the release, which could unmatched plant needs. Afterward, a second study continued in pots to compare the efficiency of different levels (25%, 50%, and 75%) of neem oil-coated fertilizer with untreated fertilizer and the control on wheat’s physiological parameters and yield. It was noteworthy that a reduced dose (75%) of fertilizer gave a better response for improving growth parameters and nutritional status of wheat. Overall, urea fertilizer coated with neem oil improved crop management and reduced nitrogen loss in environmental consequences, which usually resulted from adding traditional fertilizers. Thus, using naturally occurring neem oil as coating material could improve wheat yield and reduce nitrogen losses.

Keywords: Wheat (T. aestivum L.), nitrogen, neem oil-coated urea, slow-release fertilizer, grain yield

Key findings: Utilization of suitable coating material can slow down the release of N from urea. This study proved the use of neem oil as a coating material significantly reduced the N release and N losses from urea fertilizer used in the wheat crop.