**1.1. General background**

Replace environmental land degradation has recently become a global, urgent issue, and is now being considered with high priority, especially in the developing countries in order to meet the food and fiber demands of accelerated population pressure with limited available resources. One of the goals of irrigation is to boost food production in a sustainable technique so that a fast growing global population could be fed. Sustainable irrigation scheme can only be achieved effectively by taking into consideration the environmental effectiveness and availability of funds to maintain the implemented project. The function of irrigation is to apply water to maintain crop evapotranspiration, the total amount of available water essential for economy, health, and welfare of a very large part of the world [5]. Analyses of information from Asia have also shown that yields per area, for most crops have increased between 100 and 400% because of irrigation [6]. Based on the management system of irrigation scheme, it can provide both positive as well as negative effects on vegetation cover. Well-planned irrigation scheme have good natural vegetation conservation and management plans. Several factors could influence the salinity levels of irrigated land. One of the factors is the irrigation method [7].
