Das Projekt "Auswirkungen der Bewässerungssteuerung auf Wasserbedarf, Wasserhaushalt und Pflanzenproduktivität" wird vom Umweltbundesamt gefördert und von Leibniz Universität Hannover, Institut für Wasserwirtschaft, Hydrologie und landwirtschaftlichen Wasserbau (IWW) durchgeführt. Syria is one of the Mediterranean Arab Countries with quite limited water resources but large areas good for crops. In Syria, the irrigated area does not exceed forty per cent of the total area good for crops. This is due to scarcity of water and following the old-fashioned irrigation methods like irrigation by flooding. In such methods, the percentage of wasted water reaches up to fifty percent of the water provided for irrigation. Be-sides, there are many mud canals in governmental and private irrigation projects. These methods of irrigation do not take into consideration the economical water demands for the different crops and do not organize well the proper relationship between soil and water. Consequently, studying irrigation efficiency, developing irrigation techniques and economizing in the use of water have become urgent necessities for the develop-ment of irrigated crops and improving agricultural productivity. Water is considered the major constraint to any policy for increasing agricultural productivity at the time water demand is augmenting to face the incessant increase in population. Hence it is necessary to control and manage the available water supply through changing the present cropping pattern. Indeed, water is the limiting factor of agricultural production in arid and semi-arid regions where irrigation is required either contrastively or extensively. The aim of irrigation scheduling is to guarantee high water use efficiency. The purpose of the different methods of irrigation scheduling is either to eliminate a climatic water deficit to maintain the efficiency of irrigation methods or to control the plant water status. Efficient use of irrigation water and fertilizer is important due to increased competition for water resources. Therefore, proper scheduling of irrigation is essential to increase the efficiency of water and fertilizer use.The aim ofthe research is to study the following topics:1. Evaluating the climatic, soil and water resources data of the study area.2.Estimating the water requirements for the different crops.3. Determining irrigation efficiency according to the different irrigation methods by field studies. 4. The impact of irrigation methods on productivity developing water-yield-relationships.5.Hydraulic accounting for the different water nets.6.Irrigation system management for the farm level and developing an irrigation scheduling and optimization program for crops and trees.