Synergistic effect of coated urea formulations and their application timing on plant growth, nutrient acquisition, grain quality and productivity under transplanted rice in semi-arid regions

Controlled release urea has become the best management strategy to reduce nitrogen (N), losses, and improve rice productivity and nitrogen use efficiency (NUE). Therefore, this study was planned to investigate the impact of different sources of coated urea fertilizers including Neem-Coated Urea (NCU), Zinc-Coated Urea (ZCU) Sulfur-Coated Urea (SCU), and Conventional/Uncoated Urea along with different times of their application; Basal (B), Basal + Tillering (B + T), Basal + Panicle initiation (B + P) and Basal + Tillering + Panicle initiation (B + T + P) on growth, productivity, quality, NUE, and nutrients uptake under semi-arid conditions. The results showed that SCU applied as B + T remained the top performer and resulted in growth promoter, productive tillers, thousand-grain weight, and paddy yield. The same treatment combination also attained maximum NUE (28.85%, 29.05%) followed by ZCU (17.64%, 17.93%) and NCU (12.2%, 12.51%) during both years. The application of coated urea, especially, SCU also considerably increased grain amylose and protein contents, and uptake of nitrogen (N), phosphorous (P), and potassium (K). Maximum Benefit Cost Ratio (BCR) was 2.57 and 2.96 was denoted with SCU at (B + T). These findings demonstrate that SCU applied at basal and tillering stages could effectively improve rice productivity, quality, NUE, and N uptake as well as most cost-effective in semi-arid environments.