Spatial Variability and Temporal Fluctuation of Soil Salinity and Sodicity in Irrigated Areas of Amibara Districts, Middle Awash, Ethiopia

Abstract

This study was conducted to investigate Spatial Variability and Temporal Fluctuation of Soil Salinity and Sodicity in Fluvisols and Vertisols Areas of Amibara, Middle Awash, Ethiopia. A Total of 182 soil samples with two sampling depths (0-30 cm and 30-60 cm) were collected from irrigated and non-irrigated fields at the months of August, October and December. Based on the mean values of laboratory analysis result, the textural class in Fluvisols ranged from silt clay, clay loam to clay whereas it was clay in Vertisols areas. The mean pHe values ranged from moderately alkaline to strongly alkaline in both soil types. The ECe values varied from 0.48 to 21.8 dS/m and 0.70 to 5.4 dS/m, respectively for soil samples collected from Fluvisols and Vertisols areas of the AIS. The mean SAR values ranged from 1.7 to 18.2, in Fluvisols, while it ranged from 2.8 to 14.6 at 0-30 cm depth in Vertisols areas. Generally by combining all salinity and sodicity parameters, about 71.43, 19.05 and 9.52% in Fluvisols and 77.78, 11.11 and 11.11% of the soil samples in Vertisols area grouped under normal, saline and saline sodic class, respectively. The temporal trends of soil ECe varies with irrigation water application interval and type of field covers. Generally increasing trends has been occurred in fields covered by cotton crops and tree plants, while irregular trends has been observed in fields covered by sugarcane crops. Higher increment of each soil chemical properties were observed in irrigated farm compared to non-irrigated farm, at surface than subsurface soil depth and in Fluvisols than in Vertisols. Generally, in addition to quality reduction of Awash River water, poor management of irrigation, absence of adequate surface and subsurface drainage structures are aggravating soil salinity in the study area.