今回は地球研客員教授の Jiftah Ben-Asher先生に水利用に関して話題提供をして頂き、意見交換を行おうと思います。どうぞご参加下さい。
Technological development of irrigation has improved the water use efficiency (WUE) dramatically during the last 5 decades. One may identify two decades of sharp reduction in annual water application.
First from 1950 to 1960, when pressurized irrigation (sprinkler irrigation) replaced surface (gravitational) irrigation, and the second decade from 1970 to 1980, when trickle irrigation replaced sprinkler irrigation. These technological changes along with the introduction of the National Water Carrier have enabled Israel to increase the irrigated areas by about five folds during this period. Moreover, during these years the relative agricultural productivity has been also notably improved and raised 2.5 times from the reference year in 1955. In spite of the impressive development in our ability to save water and improve water use efficiency at the same time, several consecutive years of drought and overuse of water have lowered the Israeli water reservoirs level below the “red line” which marks a point of water catastrophe. With the current water crisis, should we stop irrigated agriculture and return to the rain-fed agriculture? In this lecture I tried to address the questions.