Effect of Land Use Change on Soil Carbon Stock and Selected Soil Properties in Gobu Sayyo, Western Ethiopia

Abstract Background: Land-use change is one of the major factors affecting soil degradation. The pressures of the human population on land resources have increased land-use change with more negative effects on soil carbon storage and soil properties. The objective of this study was to assess the effect of land-use changes on soil organic carbon (SOC) stock and selected soil physicochemical properties in Gobu Sayyo, Western Ethiopia. Soil samples were collected from three adjacent land uses i.e., forest land, grazing land, and cultivated lands at 0-20cm and 20cm-40cm soil depths. A total of 36 composite soil samples were collected and the major soil properties and SOC storage of the area were analyzed and computed based on their standard procedures.Results: Soil organic carbon stock was significantly (p<0.05) higher (43.09-81.86 tone ha-1) in forest land and was significantly lower (38.08-43.09 tone ha-1) in cultivated land at the of depth of 0-20cm. SOC stock decreased with dept in all land uses. Changes in land use and soil depth affected the physical and chemical properties of soil. The physical soil property such as bulk density (BD) was higher (1.62 gcm-3) in the cultivated land whereas, the lowest (1.08 gcm-3) was recorded in the forest at 0-20cm depth. Comparatively the moisture content was higher (25.89%) under forest land at the depth of 20-40cm and was lower (11.22%) under cultivated lands. The chemical soil properties like exchangeable Ca2+, Mg2+, and K+ were higher in forest lands. Organic carbon, avP, TN, ex.Ca2+, ex.Mg2+, ex.K+, and CEC were lower under cultivated lands. pH increased with depth and was higher under forest land and lower under cultivated land. Soils of the study area are in general acidic to slightly acid with pH value ranging from 4-6-6.02. The pH, SOC, TN, av. Phosphorus and CEC were higher under forest land as compared to cultivated and grazing lands. Conclusion: It can be concluded that soil organic carbon stocks, the physical and chemical properties were affected by land-use change and depth. Therefore, reducing the intensity of cultivation, adopting integrated soil fertility management, and maintaining forest land must be practiced to save the soil of the area from degradation.