Deficit irrigation of wheat under sprinkler irrigation in the newly reclaimed soils of Egypt [electronic resource].

Includes references.

Two seasons field experiments were conducted at Sugar Beet region, West Nubaria on wheat (Triticum aestivum L.) cv. Sakha 8 under sprinkler irrigation system. The aim of this study was to investigate the effect of deficit irrigation and N fertilization rate on yield and yield components of wheat grown in the newly reclaimed soils that facing conditions of limited irrigation water in order to accomplish optimum production. Five regimes of irrigation were randomly assigned as main plots, and two N fertilization rates 143 and 214 kg ha-1 (60 and 90 kg/feddan) as sub-plots in a split plot design. The irrigation regimes were selected to impose water stress throughout the growing season, and stress at one of the growth stages of wheat (vegetative, flowering, and yield formation), in addition to full irrigation. Imposing the stress at a certain stage imply that only 50 % of the crop evapotranspiration (ETc) was applied in irrigation. Data showed that the five irrigation regimes resulted in grain yield of 2801, 4571, 4345, 3994, and 5390 kg ha-1, respectively. These values were corresponding to actual evapotranspiration (ETa) of 207.9, 312.6, 381.4, 336.6, and 449.5 mm, crop factor (kc) of 0.449, 0.676, 0.825, 0.728, and 0.973, yield response factor (ky) of 0.735, 0.378, 0.538, 0.595, and 0.176, and water use efficiency (WUE) of 13.60, 14.60, 11.44, 11.89, and 11.98 kg ha-1per mm ETa, respectively. The saving of irrigation water due to deficits at the vegetative, flowering, and yield formation stages were 26.8, 13.2, and 23.4% resulted in reduction of grain yield 15.2, 19.4, and 25.9%, respectively. Several water regimes of low water application gave grain yields, which were insignificantly different from the full irrigation treatment. Reducing the applied N fertilizer from 214 to 143 kg ha-1 (33.3 %) resulted in reduction of grain yield from 4504 to 3936 kg ha-1 (12.6 %), and had little effects on the other yield characteristics. This study showed that the efficient use of limited amount of irrigation water available for wheat production was reached if applied to relieve stress during flowering (mid- late-February to mid- late-March) followed by yield formation (late-March to mid-April), and least during vegetative stage (mid-December to late-February). This can be coupled with the application of N fertilizer rate of 143 kg ha-1 which leads to optimum yield and environment sustainability

Summary in Arabic.

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