Changes in Soil Organic Carbon Stock Under Different Land Use Types in Semiarid Borana Rangelands: Implications for CO2 Emission Mitigation in the Rangelands

摘要

Understanding the impact of land use change on soil organic carbon stock following the conversion of a semiarid rangeland into different land use types is essential to devise an appropriate and sustainable rangeland management strategy. However, there is a knowledge gap as to the impact of currently ongoing land use changes on soil organic carbon stock, which is an important rangeland ecosystem service, particularly in the face of climate change. Thus, this study was conducted to assess the effect of land use change on soil organic carbon stock in three land use types, namely, enclosures, communal grazing and cultivated lands in Borana rangeland. The result indicated that there were significant interactions between land use types and depths for soil organic carbon stock (p<0.0001) and bulk density (p=0.0055) with mean losses of 60% and 69% in soil organic carbon stock from the surface layer (0-10 cm) of communal and cultivated lands, respectively, as compared to enclosure land use type. The results indicated that communal grazing and crop cultivation in the Borana rangeland resulted in significantly decreased soil organic carbon stock. Hence, the current trend must be curbed to put back the system on its right track of resilience and sustainability for its long-term benefit and to mitigate the unprecedented increase in CO2. Therefore, the results of this study would be useful for the improvement of land use management in the future.