FUTURE CHALLENGES OF IRRIGATED AGRICULTURE USING POOR QUALITY WATER

Since the development of new water supplies in the future are unlikely to keep pace with the increasing water needs of industries and munici palities, irrigated agriculture faces the need to increase production with less water, in many instances of poorer quality. At the same time , there is a need to reduce and control negative environmental impacts on surface and ground waters - an inevitable consequence of irrigatio n. Four aspects of water management are important when dealing with th e use of poor quality water for irrigation: (1) selection of appropria tely salt tolerant crops and control of soil salinity through leaching ; (2) maintenance of soil physical properties to assure soil tilth and adequate soil permeability to meet crop water and leaching requiremen ts; (3) improvements in water management, and in some cases, the adopt ion of advanced irrigation technology; and (4) acceptable disposal met hods for either the drainage water, or the salt it contains. This revi ew covers research, the application of available computer models to wa ter, salt, and soil management, and farmer experiences in these areas. The focus of the paper is on technologies, developed by researchers a nd farmers, that facilitate the use of poor quality irrigation waters while at the same time minimizing adverse impacts on crop yields and s oil physical properties of irrigated lands, and on-site environmental impact. These technologies pose the need to be more aware than ever of the off-site environmental problems posed by the need to dispose of t he saline drainage waters with acceptable impacts on the environment.