A comprehensive review is presented of irrigation water management principles, factors to be considered in improving irrigation water management, leaching requirements, climatological approaches to irrigation scheduling, scope of irrigation scheduling services in 1974, basic concepts of scheduling services and probable effects of scientific irrigation scheduling on salinity of return flows. A definition of irrigation water management efficiency is presented to evaluate the annual volume of irrigation water used relative to the optimum amount needed for maximum annual crop production or income. The term considers the minimum, but essential water needed for both consumptive and nonconsumptive uses. The lack of significant changes in irrigation efficiency during the past several decades is discussed and attributed to problems associated with the management of a complex soil-crop-environment system, a lack of economic incentives to make improvements, and ineffective traditional approaches to improve irrigation scheduling. New proposed minimal leaching practices are discussed.

"Interagency Project no. EPA-IAG-D4-F399." Report prepared by U.S. Department of Agriculture, Agricultural Research Service, Western Region, Snake River Conservation Research Center, Kimberly, Idaho. Includes bibliographical references (pages 80-88).