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sur le développement des zones arides et semi-arides

Titre : Computer based expert system to optimize the water supply for modern irrigation systems in selected regions in Egypt

Auteur : Hokam, Essam Mohamed

Université de soutenance : Justus-Liebig Universität Giessen

Grade : Doctor Degree in Agriculture (Dr. agr.) 2002

Résumé
The investigation attempts to find further ways for overcoming the water scarcity problem in Egypt, where the existing water resources are less than the water demand. This study aims to increase the water use efficiency through optimizing the irrigation water supply of a certain area in Egypt (Suez-Canal region), where additional areas for agricultural production will be irrigated with saline water (Salam-Canal water). As results three ways were developed to achieve a greater water use efficiency and an irrigation water saving : Improved ETo oriented geographic distribution of crops (IGDC), a daily data based model for irrigation scheduling (DDBM) and reduction of leaching requirements. The Penman-Monteith equation has been selected for calculation of the main factor influencing the plant water requirement i. e. reference evapotranspiration, ETo. The first way (IGDC) means that crops with high water requirements are to be cultivated in regions with low reference evapotranspiration and vice versa. For example, it was suggested that maize should be cultivated in El-Arish while sunflower should be cultivated in El-Ismailia that has the highest reference evapotranspiration. In such case a quantity of approximate 60.000 m³ of water can be saved per season of only 100 ha. These 60.000 m³ resulting from a reorganisation could be used for soil amelioration (desalinisation) or could be used to irrigate other areas. By the second way (DDBM) the soil-plant-climate parameters were applied as daily values (in comparison with the use of average values). The results showed that the DDBM can lead to irrigation water saving and that a balance between the actual plant water requirement and applied irrigation water can be achieved. The third way introduced an economic irrigation water quantity concept, and an equation to secure the last 10 % of yield (that can be lost due to an inexact scheduling). This equation enables the expert to calculate a safety reserve to be added to the quantity of irrigation water calculated after Richard´s equation

Mots clés : Ägypten ; Bewässerungsfeldbau ; Ertragssteigerung ; Bewässerungsplanung ; Mathematische Methode

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