Influence of Nitrogen Fertilization Pattern on Productivity, Nitrogen Use Efficiencies, and Profitability in Different Rice Production Systems

The major challenge in sustainable rice production is to achieve the goals of increasing crop productivity, profitability, and resource use efficiency. Production systems (PS) and nitrogen (N) management patterns are two key agronomic practices influencing crop performance, profitability, water use efficiency (WUE), and N use efficiency (NUE). So, this study was conducted to check the influence of split application of N on rice productivity, NUE and profitability under dry direct-seeded rice (DDSR) and transplanted rice (TPR) systems. A field study was conducted in the summer season of 2017 and 2018 to investigate the influence of two PS (dry direct-seeded rice = DDSR and transplanted rice = TPR) and six N management treatments (N₁ = control, N₂ = 50 kg N ha⁻¹ as basal, N₃ = 100 kg N ha⁻¹ as basal, N₄ = 150 kg N ha⁻¹ as basal, N₅ = 100 kg N ha⁻¹ in three splits and N₆ = 150 kg N ha⁻¹ in three splits) on crop productivity, profitability, and resource use efficiency. Yield-related traits, spikelet sterility, WUE, and profitability aspects were significantly influenced by PS. All aspects of crop performance, kernel quality, N uptake, and NUE (except NUE on biomass basis = NUEB) were affected by N management pattern, while no significant interaction between PS and N management was observed for any aspect. On average, DDSR improved the productive tiller density (26%), biological yield (16%), WUE (14%), and NUEB (27%) as compared with TPR. Similarly, DDSR reduced the cost of production (31–43%), while maintaining statistically similar paddy yields and reducing total water inputs (5–17%) in comparison with TPR. Among N management pattern, 100 kg N ha⁻¹ in three splits increased paddy yields (44%), and WUE (42%) as compared with the basal application of 100 kg N ha⁻¹. Similarly, application of N at 100 kg ha⁻¹ in three splits improved the total N uptake (42%), agronomic NUE (146%), apparent recovery efficiency (226%) while reducing the spikelet sterility (28%) as compared with the basal application of 100 kg N ha⁻¹. The DDSR has the potential to maintain or increase yield, WUE, NUE, and economic returns. While, split application of N at 100 kg ha⁻¹ either in DDSR or TPR not only increased the SPAD-chlorophyll value, WUE, NUE, and economic returns but also reduced the spikelet sterility.