Advances in quantifying soil organic carbon under different land uses in Ethiopia: a review and synthesis.

Background: In the face of climate change and global warming, scientists globally are striving for effective techniques on how best to sequester carbon in order to reduce global warming and achieve environmental sustainability. This paper reviews the available literature on the influence of various land use changes on gains and/or losses of soil carbon (C) stocks in Ethiopia. Results: Our review indicated that 33.3% of the studies reported soil organic carbon (SOC) concentration, 13.9% reported only SOC stock while 52.8% reported both SOC concentration and stock. Studies focusing on 0–30 cm only were 44%, other studies extending up to 40 to 100 cm were 50%, and studies extending to more than 100 cm accounted for 2.8% while studies without any depth specification accounted for 2.8%. Irrespective of soil type, C stocks in the top soil (0–30 cm) were found to be higher than at subsoil depths. Even though there is significant improvement in C sequestration in exclosures and community forests, the level of C sequestered is still below that of church forests. Conclusion: Conversion of native forest to other land uses resulted in a significant decrease in the SOC stocks across Ethiopia. Absence of long-term field trials and non-existence of SOC database are among the major drawbacks of SOC studies in Ethiopia identified in this review. With better management practices, it is possible to restore depleted C concentrations and stocks even in degraded lands and to conserve C in more pristine lands across the rugged landscapes of Ethiopia. [ABSTRACT FROM AUTHOR]