Understanding soil organic carbon (SOC) dynamics is pivotal for global change research, as soils are one of the largest carbon pools and a small change in SOC content could therefore substantially intensify, or mitigate, current atmospheric CO2 increase. However, the release or increase in SOC is a slow process originating from a SOC pool with a large spatial variability. At the various larger spatial scales of regions, landscapes, and catchments, different processes jointly determine the balance between accumulation and decomposition of SOC. The corresponding carbon inventories as measured by CO2 fluxes or soil C budgets at different spatial scales are still surrounded with large uncertainty. This is largely because SOC consists of fractions with different ages resulting in different turnover times from years to millennia. Some of these fractions react to the present carbon balance, whereas others are inherited under different conditions and reflect past land-use.
Mountain soils have been found hot spots for land use and land management changesand they play a critical role in the global carbon cycle. They can be used as examples to enlarge our understanding on SOC characteristics and rates of SOC changes due to global change and direct anthropogenic perturbations.

In this session, we welcome studies on SOC dynamics using measured CO2 fluxes, SOC inventories or applications of SOC dynamics models highlighting the challenges tracking SOC stock changes due to land use and land management.