Assessement of physicochemical properties of soils from different land use types and soil depths in senaga harawe kebele, dega district, buno bedele zone,oromia regional state southwest Ethiopia

Abstract

The study was conducted to determine the status of selected physicochemical properties of soils under different land use types (cultivated, grazing and forest lands) and soil depths (0-20 cm and 20-40 cm) in Senaga Harawe Kebele, located in the Dega District of Buno Bedele Zone, Oromia National Regional State Southwest Ethiopia. The soil samples were collected from the selected land uses and soil depths with its replications and finally eighteen total composite soil samples were collected from the mentioned depths. Comparisons between cultivated, grazing and forest land use types revealed a high significant difference on selected soil physicochemical properties. Soil texture (sand, silt and clay) studied was significantly affected (P ≤ 0.05) by land use types and soil depths. Among land use types, the highest mean clay (45.04%) and bulk density 1.43 g/cm 3 values were obtained in the forest and cultivated land respectively. Considering the land use types, the highest soil pH (H2 O) (5.9) and the lowest (4.79) were recorded in the subsurface soil layer of forest and surface soil layer of cultivated land, respectively. Moreover, the range of soil pH in the surface and subsurface layers of both cultivated and grazing land use types were strongly acidic with pH (H 2 O) as well as pH (KCl). On the other hand the highest average mean values of available P (9.10 mg/Kg), and SOM (5.10%) were recorded in the surface soil layer of the cultivated and forest lands. In addition, the highest mean values of EA (3.8 cmol( + )/Kg), CEC (30.79) cmol( +)/kg) and TN (0.26%) were recorded in the surface soil layer of the cultivated land ,but TN in the forest land. The mean value of exchangeable bases (Na, K, Ca and Mg) were higher (0.20, 1.60, 5.42, and 7.56 cmol( + )/kg) on the subsurface of the forest land. Generally, it is possible to conclude that soil physicochemical properties of the study area were significantly varied among land use types. Therefore, reducing the intensity of cultivation and grazing, application of lime and organic fertilizers could maintain the affected soil physicochemical properties of the study area.