Economic factors and opportunities as determinants of water use efficiency in agriculture

A consequence of water scarcity is that it has enhanced research and development aimed at increasing water use efficiency in irrigated agriculture. Although biological, genetic, and technological achievements may induce potential high levels of water use efficiency, actual observed values may be much smaller. This paper distinguishes between potential and actual water use efficiency measures, and discusses factors and opportunities that may affect actual water use efficiency in irrigated agriculture. These include economic forces, environmental effects, and institutional arrangements, each of which may affect water use decisions at field, farm, regional, and national levels. The paper develops a scheme to generally address differences between private and social considerations that determine water use efficiency decisions. Using this scheme, several examples from California and Israel are provided to support the arguments. The paper concludes that the concept of water use efficiency is much broader than its definition: yield per water applied or transpired. Moreover, determination of water use efficiency levels in irrigated agriculture is a complex issue that requires interdisciplinary considerations.