ABSTRACT
Irrigation involves complex interactions among ecological, social, and economic processes at a variety of scales, with important implications for agricultural production, income generation, poverty reduction, and environmental quality. No simple measure can fully capture the global economic importance of irrigation. Nevertheless, a review of historic trends in agricultural demand and resource use indicates that irrigation has contributed to dramatic increases in global crop yields and production over the past four decades. Given projected trends in demand for agricultural commodities and in the availability and condition of land and other natural resources, irrigation will continue to play a critical role in the future. Improved management will be necessary, however, to balance public and private economic and environmental objectives.
