Impact of Water Table Depth Fluctuation, Irrigation and Groundwater Quality on Occurrence of Salt Affected Soils in Amibara Districts of Afar Region, Ethiopia

Abstract

This assessment work was done to investigate the impact of depth of water table dapeth, irrigation and groundwater quality on the occurrence of salt affected soils in Amibara irrigation scheme. Depth of water table and water sample were taken for five consecutive months from 30 sampling piezometers. Totally 180 soil samples were collected at the months of August, October and December, at depths of 0-30 cm and 30-60 cm in 2017. The Correlation analysis result between irrigation water ECw and soil ECe revealed the presence of significant correlation (r = 0.99) in Vertisols at 30-60 cm depth at (P ≤ 0.05) level of significance. Correlation analysis result between depth of water table and soil salinity revealed significant correlation in Fluvisols, but not in Vertisols. The correlation result between ground water ECw and soil ECe showed a significant correlation (r = 0.73 and 0.71) and (r = 0.89 and 0.74) at 0-30 and 30-60 cm, respectively, in Fluvisols, while it showed a significant correlation (r = 0.86, 0.96 and 0.95) at 0-30 cm along the sampling months in Vertisols. The correlation result between ground water and soil SAR showed a significant positive correlation (r = 0.75, 0.55 and 0.66) and (r = 0.62, 0.58 and 0.69) at 0-30 and 30-60 cm soil depths, in Fluvisols area but it showed a significant correlation (r = 0.93) at 0-30 cm only at October in Vertisols area. Generally, in addition to quality reduction of Awash River water, poor management of irrigation, absence of adequate surface and subsurface drainage structures were aggravating soil salinity in the study area. Therefore, efficient irrigation practice and maintenance and construction of surface and subsurface drainage structures should be implemented as soon as possible to alleviate the expansions of soil salinity and sodicity problem in Amibara irrigation.