SUSTAINABLE USE OF SOIL AND WATER RESOURCES FOR IRRIGATION: IRRIGATION EFFICIENCY AND WATER PRODUCTIVITY

Abstract

Agriculture plays a vital role in the economies of many countries and irrigation make it a crucial actor to increase crop production. In the world, 70% of available water resources are used for agricultural irrigation. However, it is almost 90% in some countries in the world. The main and common problems and challenges in agricultural irrigation are observed as excessive water use by farmers in some areas with surface irrigation, insufficient land leveling, no use of appropriate furrow and border length according to water flow and soil texture, irrigation water application without volumetric measurement of water, low irrigation water use efficiency and water productivity, drainage and salinity issues, alkalinization, impact of climate change (drought), the low effectiveness of the water user associations, improper crop pattern (monoculture), insufficient design and management of pressurized irrigation systems, inadequate irrigation pricing policies, weak cooperation among the instittutions and political instability in some countries. Irrigation efficiency (IE) (35-40%) and irrigation water productivity (WP) are very low and use of gross irrigation water is more than 10,000 m³ ha^-1 in some Middle East countries. IE (%) WP (kg m^-3 and $ m^-3) are the most important indicators for evaluation criteria of irrigation schemes and farms, irrigation authorities and decision makers. Thus, the importance of  IE and WP for sustainable use of soil and water resources, some actual and experimental data regarding those issues, problems and recommendations considering technical and institutional approaches are discussed.