Soil Properties

Ethiopian soils greatly vary in their morphological, physico-chemical and mineralogical properties due to the wide variations in soil forming factorsSoil forming factors and the associated processes. The different soil typesSoil types of the country show great variation in their morphological propertiesMorphological soil properties such as depth, color, structure and consistence. Across the country, the sand content varies from 1 to 75%; silt from 9 to 60%, and clay from 10 to 86%. The clay content of Ethiopian soils ranges between 10 and 86%. About 48.65% of the country’s total area is covered by soils whose clay content is greater or equal to 35%, indicating that most. About 0.38% of the country’s total area is covered by soils whose bulk densityBulk density in the upper 0–20 cm is less than 1.0 g/cm3. And about 5.36% of the country’s total area is covered by soils with total porosityPorosity values that vary from 60 to 71.06%. When it comes to soil chemical properties, soil reactions in Ethiopian soils can be broadly grouped into three categories. The soils in the highlands of north-western, western and central parts of Ethiopia are predominantly acidic. The Rift Valley, the lowlands of eastern and southern regions and arid dry highlands of Tigray are dominated by alkaline soils. Ethiopia’s highlands, covering approximately 40% of the nation, historically have extremely low soil carbon content. About 36.39%, 26.17%, 33.42%, and 2.37% of the Ethiopian landmass has soil organic carbonSoil organic carbon content of very low, low, medium, high and very high respectively. About 48.92% of the soils of the country have high, 25.45% have very high and 19.07% have medium CEC levels. Only 3.36% of the soils have low CEC levels. Soil salinity is one of the major land degradation problems in Ethiopia. The country stands first in Africa in the extent of salt affected soils. About 44 million ha (36% of the total land area) is potentially susceptible to salinity problems of which 11 million ha have already been affected by different levels of salinity. Soil sodicity is the problem of dry areas in Ethiopia mainly Afar and northern parts of the Somali Regions. About 4,250 km2 of sodic soils exist in Ethiopia. Relative abundances of the different minerals identified in the different soil typesSoil types of the country based on the intensity of X-ray diffraction peaks for the different minerals are quite variable among the different soil reference groups. Among others, Ethiopian NitisolsNitisols contain a large quantity of 1:1 minerals like kaoliniteKaolinite and a small quantity of 2:1 clay minerals such as smectite Illite and mixed-layer minerals. Many Ethiopian VertisolsVertisols contain illite as the dominant mineral while smectite dominates in some Vetisols. The LuvisolsLuvisols have a large amount of 1:1 clay minerals mainly kaolinite with high-intensity diffraction peaks.