Improving irrigation efficiency in the lower reaches of the Amu Darya River

Abstract

The problem of water scarcity in Khorezm region of Uzbekistan, situated in the lower reaches of the Amu Darya river basin, has been exacerbated by regional political decisions and mismanagement of irrigation systems. Previous studies revealed that despite there being temporal and spatial water scarcity in the region, there remains excessive water use for strategic cotton production. Excessive irrigation to cotton crop has led to overall inefficiency of the irrigation system. Moreover, there remains negligible information regarding the level at which the irrigation losses occur. Therefore, the objective of this study was to track the losses of irrigation at field level due to excessive irrigation. For this purpose, results of extensive experimentation during the 2010 cropping season were used to determine field application efficiency. For this purpose, soil moisture deficit was determined at 30, 60, 90, 120 and 150 cm depths before and after each irrigation event. The ground water level fluctuation was measured twice a week at 3 different locations per field (cotton and maize). Results show that the field application efficiency (FAE) during the three irrigation events for cotton at field 1 were 43 %, 21 % and 15 % respectively. Similarly the FAE calculated during the 3 irrigation events at another cotton field 2 were 48 %, 37 % and 22 % respectively. The FAE calculated at the maize field 3 was 42 %, 57 % and 23 % in the 1 st , 2 nd and 3 rd irrigation event respectively. The standing reason behind the higher water losses at the farm lever were the poor irrigation management practices and poor canal infrastructure.