Evaluation of wheat with different coated controlled release urea and application time in semi-arid conditions

Optimal nitrogen (N) application rate, source and timing are important to achieve high wheat yield. Overdose of N as basal dose promotes excessive vegetative growth and delays maturity, resulting in low N use efficiency (NUE) and crop yield. The current study was conducted for two years (2018-2019 and 2019-2020) to examine the influence of various N sources viz., common-urea, Zn-coated urea, neem-coated urea, and polymer-coated urea and their application methods (basal-and split-application) on the growth, physiology, yield, and related traits in wheat under semi-arid conditions. Results showed that N sources and application methods significantly affected the growth, physiological and yield-related traits; neem-coated urea applied in splits remained the most effective source for the observed traits, followed by Zn-coated, polymer-coated, and common urea. Compared with common urea, neem-coated urea significantly increased chlorophyll (Chl) and carotenoid contents under basal and split application. Neem-coated urea also recorded higher biological and grain yields than other treatments which were associated with higher values of yield-related traits including the number of productive tillers, number of spikelets, and number of grains per spike. For N application methods, split application significantly improved the plant height, Chl pigments, yield-and yield-related traits compared with the basal application. In conclusion, neem-coated urea application as a split application performed well followed by Zncoated and polymer-coated urea in improving the growth and overall yield.