Effect of land-use types and slope gradients on soil organic carbon stocks in the Shabo Kalo micro-watershed, Lalo Kile district, Western Ethiopia
摘要
The purpose of this study was to examine how different land-use types and slope gradients influence soil organic carbon stock (SOCS) in the study area. The relationship between land-use categories and environmental change is of particular importance, as soils play a critical role in sequestering and storing atmospheric CO2, thereby contributing to climate change mitigation. To achieve this objective, soil samples were collected from four slope classes that were purposively stratified within each land-use type to assess the combined effects of land use and slope on SOCS. Soil samples were collected from 12 plots (10 m × 10 m) using a diagonal sampling approach with three replications. Undisturbed soil samples were obtained using a core sampler to determine bulk density across land-use types and slope gradients. In addition, 36 disturbed soil samples were collected from a depth of 0–30 cm using an auger to analyze SOCS at the watershed scale. The results indicated that both slope gradient and land-use type had a significant effect on SOCS. The highest SOCS value (71.3 Mg ha−1) was recorded on gentle slopes under forest land, whereas the lowest value (29.8 Mg ha−1) was observed on steep slopes under grazing land. In terms of carbon dioxide equivalents, one hectare of forest land soil sequestered 250.29 Mg CO2 ha−1, which was substantially higher than that of grazing land (195.98 Mg CO2 ha−1) and cultivated land (127.35 Mg CO2 ha−1) within the 0–30 cm soil depth. The findings of this study contribute to raising awareness among local farmers, relevant government institutions, and non-governmental organizations about the importance of sustainable land use and soil management practices for climate change mitigation.