الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Climate change is major keywords in the present-day global change discussion. Climate change and agricultural development processes have interaction dynamic effects. Concerning the water crises that Egypt face, maximizing water crop production is a must, so better estimations of irrigation water requirements are necessary. Although citrus is the first product in export and has a high return on hard currency. Citrus fruit production and quality are influenced by many factors, including climatic conditions and production practices.
The objectives of this study: Using geographic information system for maximizing water use efficiency, improving the efficient and sustainable use of irrigation water and the optimum estimation of crop water requirements to maximize crop productivity.
The main results of this study could be summarized as follows:
• Estimating evapotranspiration (ETo) by Blaney-Criddle (BC) was more than Penman-Monteith (PM) equation under all months and the rate of increase was small under the summer season while a higher increase was observed under cold months.
• The study compared between BC and PMs ETo at 2.6 and 8.5 scenarios and indicated that the minimum ETo values estimated by both equations were found in February and July.
• A relatively uniform soil salinity profile was found either before or after irrigation after PM equation, where the water was the same salinity but the soil salinity differs, the new soil salinity varied considerably with distance from emitter.
• If the temperature rises by one degree above the average, the consumption of citrus fruits will increase by 143 and 126 m3/year according to equations PM and BC , respectively experimental conditions.
• The application of the Penman-Monteith equation led to a decrease in the amount of applied irrigation water to citrus trees by about 20% (900m3/year that can lead to a water saving of about 450m3 used in the cultivation of new areas.