Characterization, Classification and Mapping of Soil Resources in Adami Tulu Jido Kombolcha District of East Shewa Zone, Oromia

A study was undertaken in Adami Tulu Jido Kombolcha District of Oromia region, Ethiopia, to investigate the site, morphological and physico-chemical characteristics, classification and mapping of soils. Fourteen soil pedons at representative sites were described and 66 disturbed and undisturbed soil samples from identified horizons were taken for laboratory analysis. The data obtained showed that the soils varied from moderate to very deep, well drained, the surface soil color at (dry) varied from light gray (10YR 7/2) to very dark brown (7.5YR 2.5/2); at moist varied from brown (10YR4/3) to black (10YR2/1), while the subsurface color varied from white (10YR 8/1) to black (7.5YR 3/1,) at dry conditions and at moist condition the color varied from light gray (7.5YR 7/2) to black (7.5YR 2.5/1), the structure in the surface layers of the pedons 1, 2, 3, 6, 14 had weak fine granular and gradually in subsurface changed to Moderate fine sub angular blocky in the same pedons; Strong fine granular at surface changed to strong fine sub angular blocky in pedon 4; Strong fine angular blocky in pedon 5 and moderate medium granular in pedon 7 and 8 at surface and subsurface without gradual change. The values of the determined soil physical characteristics revealed that sand, silt, clay, bulk density and total porosity ranged from 34 to 81.78%, 9.22 to 48%, 5 to 28%, 0.95 to 1.31 g cm⁻³, 50.56 to 64.15% respectively. Moreover, the soils were neutral (pH 6.7 to 7.3) to strongly alkaline (pH >8.0), salt free (< 1dsm⁻¹) except pedon 9 and 10 near to lake Abjeta. Soil organic matter content ranged from very low to moderate in and total N ranged very low to moderate, available phosphorus ranged from very low to low respectively. Soil exchangeable Ca²⁺ ranged from moderate to high (5.13 to 21.8 cmol(+) kg⁻¹), high to very high in exchangeable K (0.65 to 3.46 cmol(+) kg⁻¹), moderate to high in Mg (1.28 to 6.7 cmol(+) kg⁻¹), low to very high in exchangeable Na (0.13 to 10.1 cmol(+) kg⁻¹) and, moderate to high CEC (13.13 to 38.88% cmol(+) kg⁻¹) and moderate to very high PBS (50.92 to 97.69%), respectively. Soil of the district was classified as chromic vertisols, Luvic phaeozems, vitric andosols, Solonetz and mollic andosols.