Yield, Grain Protein Content and Input Use Efficiency in Wheat as Influenced by Irrigation and Nitrogen Levels in a Semi-arid Region

A field experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi during 201112 to 2012–13 to study the interactive effect of irrigation and nitrogen (N) fertilizer on yield, grain protein content, and water and N use efficiency of wheat. The design of the experiment was split-plot with irrigation (I₀: rainfed, I₂: two irrigations, I₃: three irrigations, I₅: five irrigations) as main plot and N (N₀: 0 kg N ha⁻¹, N30: 30 kg N ha⁻¹, N60: 60 kg N ha⁻¹ and N₁₂₀: 120 kg N ha⁻¹) as sub-plot treatment. Averaged across the years, I5 treatment registered 4, 33 and 192 per cent higher grain yield compared to I₃, I₂ and I₀ treatments, respectively. Similarly, N120 treatment registered 19, 42 and 93 per cent higher wheat grain yield compared to the N₆₀, N₃₀ and N₀ treatments, respectively. The I0 irrigation treatment registered 23, 25 and 16 per cent lower water use efficiency (WUE) compared to the I₂, I₃ and I₅ treatments, respectively. The I₅ irrigation treatment registered 3, 32 and 200 per cent higher partial factor productivity of N (PFP_N) compared to I₃, I₂ and I₀ treatments, respectively. Thus, wheat may be grown with three irrigations at crown root initiation, tillering and flowering stages with 120 kg N ha⁻¹ for higher yield, grain protein content and WUE in the semi-arid environment of Delhi.