Abstract

A soil profile representative of typical soils of Abelo area Masha District, South-west Ethiopia, was dug to study its morphology, physico-chemical characteristics and to classify it using two internationally known soil classification systems. Disturbed and undisturbed soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. Soil morphological observations revealed that the pedon was well drained and very deep with dark brown to dark yellowish-brown topsoil overlying brown to strong brown sandy clay loam to sandy clay subsoil. Clay eluviation - illuviation was a dominant process influencing soil formation in the study area as indicated by the clay gradient between the eluvial and illuvial horizons in the subsoil. The soil was characterized by weak fine sub angular blocky structure throughout its Pedon depth. Laboratory analysis indicates that the soil was very strongly acid (pH 4.49-5.2) throughout the profile, the pedon has low N (0.1-0.13), low to medium OC (1.3-1.87%). Low Av. P (3.4-8.5 mgKg^-1), low C:N (13-14.38), Available. K (25–54 mgKg^-1), Low to medium Ca (5-7.12 cmol (+) kg^-1soil), medium Mg (1.5-2.16 cmol (+) kg^-1 soil), medium K(0.32-0.41 cmol (+) kg^-1soil), TEB (6.82-9.69), Ac(2.4-3.58), Al(1.8-2.52), moderate CEC(18.8-21.44 cmol (+) kg^-1), ECEC (9.22-13.28) CECclay (37.6-46.41 cmol (+) kg^-1), high Pals (9.81-13.59%), high PAcs (11.11-16.66%), low (PBS<50%), low Ca/Mg (3.06-3.33), medium Mg/K (4.41-6.68), high K/TEB (0.035-0.05), low Calcium saturation (26.88-34.67%), low Magnesium saturation (8.06-10.80%), Textural class (sandy clay loam-sandy clay), Bd (1.32-1.36 gcm^-3), high Pd (2.708-2.766 gcm^-3), and porosity (50.83-51.25%). Using field and laboratory analytical data, the representative pedon was classified to the series level of the USDA Soil Taxonomy as Abelo, fine-loamy, siliceous, thermic, Rhodic Paleudults and to Tier-2 of WRB as Rhodic Nitosols Ortho dystric. The general fertility of the soils of the area is discussed highlighting their potentials and constraints.

Keywords: Soil characterization; Soil chemical properties; Soil classification; Soil fertility evaluation; Soil morphological properties; Soil fertility evaluation; Soil physical properties