Assessment and Characterization of Agricultural Salt-Affected Soils around Abaya and Chamo Lakes, South Ethiopia Rift Valley

Abstract

Soil salinity/sodicity is becoming a challenge for crop production in Ethiopia’s semi-arid and arid regions. However, more information on soil salinity/sodicity needs to be available around Abaya and Chamo Lakes, South Ethiopia Rift Valley. This study aimed to assess and characterize soil salinity/sodicity and determine salt-affected soils’ morphological, physical, and chemical properties. The representative soil pits that were 60 $\ast$ 60 $\ast$ 60 cm in size were examined, and samples were taken from 0–20, 20–40, and 40–60 cm depths based on the criteria set for agricultural salt-affected soil studies. The soil properties determined include soil color, structure, consistency, bulk density, particle density, porosity, texture, pH, EC, SAR, ESP, CEC, BS, OC, TN, available P, CaCO3−, exchangeable bases, and soluble ions (Na+, Ca2+, Mg2+, K+, Cl−, SO4−2, NO3−, CO3−2, and HCO3−. The soil-analyzed results were rated and interpreted following a guide to standardized analysis methods for soil data. The results of this study reveal that the soils had considerable heterogeneity in soil morphological, physical, and chemical properties. The soils of the study site were highly alkaline and had very high sodium content, very high CEC value, and low levels of organic carbon and exchangeable calcium. The dominant soluble cation was sodium, followed by magnesium, calcium, and potassium in all soil depths of the pits. Similarly, Cl− was dominant among the anions throughout the soil depth, followed by HCO3−, SO42−, and NO3−. The findings of this study imply that removing sodium and salts from the soil depth may improve the salt-affected soils’ productivity in the study area. Application of organic amendments, including manures and crop residues, may also be beneficial in increasing fertility and organic matter content.