2018 年 28 巻 S 号 p. 155-158
In Central Asia which belong to the arid land, secondary salinization caused by incorrect irrigation has become a serious problem. Water-saving techniques, drainage improvements, and leaching have been adopted as general measures to mitigate salinization. However, the construction of water-saving and drainage facilities requires plenty of funds. A relatively easy and inexpensive water-saving method is skip furrow irrigation (SFI), by which every alternate furrow is irrigated. In regular SFI, furrows are irrigated alternately (ASFI) during each irrigation event. However, if the irrigation furrows are fixed (FSFI), the salts in the soil might be pushed towards the other side of the ridge. To analyze this salt distribution, a field study comparing every furrow irrigation (EFI), ASFI and FSFI was conducted at a farmland in Uzbekistan. In EFI, the salt content in the center of the ridge increased. Also in ASFI, the salt content decreased at the wet side of the ridge but after second irrigation, increasing at the center of the ridge. Whereas in FSFI, the salt content on the left (dry) side of the ridge increased, indicating a salt pushing effect. The findings of this study suggest a possibility of more efficient removal of the salt in the surface soil by combining FSFI and the dehydration method.
