Wheat Response to Nitrogen and Irrigation under Semi-Arid Conditions

Drought is the most important limiting factor of the agricultural plants production in Egypt and the world. Nitrogen application management under water limited condition needs to be refined for low yielding environments. Therefore, to see how restricted irrigation and different nitrogen fertilizer affect yield, its components, water use efficiency and nutrients uptake of wheat, an experiment was conducted in a semi-arid area in Assiut, Upper Egypt in 2013/2014 and 2014/2015. Split-plot experimental design was used, based on a complete randomized block design with three replications. The variables were two water treatments and three levels nitrogen fertilization. The main plots were used to express irrigation regimes (100% of water requirements (I₁₀₀= 5370 m³ ha⁻¹) and 75% water requirements (I₇₅= 4027 m³ ha⁻¹)). The split units were assigned for nitrogen fertilizer levels (N₁₂₀=120, N₁₈₀ =180, and N₂₄₀ =240 kg ha⁻¹). The results showed that fertilization of drip irrigated wheat grown under I₇₅ with N₃₆₀ increased the uptake of N, P, and K by 17, 32, and 2%, respectively, compared with N₂₂₀. Fertilization of drip irrigated wheat grown under I₇₅ with N₂₄₀ increased the grain, straw, and biological yield by 51, 14, and 22% respectively, compared with N₁₂₀. Fertilization of drip irrigated wheat grown under I₇₅ with N₂₄₀ increased the WUE by 22 and 23% in the first and second seasons respectively, compared with N₁₂₀.

Keywords: Drip irrigation; Water stress; N fertilization; Nutrients uptake; Water use efficiency