Simulation of Wheat Yield Using the RZWQM as Affected by Supplemental Irrigation in the North Western Coast of Egypt

N ARID and semi-arid regions, the amount of rainfall and its …distribution greatly affect the productivity of crops in these regions. Rainfall deficits during the critical growth stages can cause a sever crop yield losses. The study was carried out at the agricultural Experimental station, Sustainable Development Center of Matrouh Resources, Egypt, during 2014/2015 and 2015/2016 rainfall seasons to evaluate the effect of different supplemental irrigation treatments on wheat yield . The irrigation treatments included rainfall only (control), one irrigation of 50 mm at tillering or booting or grain filling, two irrigations of 100 mm at tillering and booting or tillering and grain filling or booting and grain filling, and three irrigations of 150 mm at the three stages of tillering, booting and grain filling. The obtained results showed that the application of supplemental irrigation of 150 mm at the three stages of tillering, booting and filling secured the highest significantly values of plant height (61.47 cm), spike length (9.07 cm) and number of grains/spike (46.67) in the first season only, 1000 grain weight (39.72 and 48.53 g), biological yield (5.10 and 8.72 t/ha), grain yield (1.55 and 3.40 t/ha) , straw yield (3.54 and 5.35 t/ha) and WUE (0.672 and 1.08 kg/m3) in both seasons, respectively. Wheat yield in the second season under the different supplemental irrigation treatments was simulated using the Root Zone Water Quality Model. Results showed a very good agreement between simulated and observed yields with a Nash- Sutcliff Efficiency (NSE) of 0.93. It could be concluded that supplemental irrigation is highly important for achieving a good economic yield of wheat under the rainfed condition of Matrouh Governorate, moreover the RZWQM successfully simulated the wheat yield under water stress conditions.