Understanding the effects of land use change and land
management on soil organic carbon (SOC) dynamics is pivotal for global change research. 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 spatial scales of field site, catchments, landscapes and regions 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 makes it challenging to disentangle anthropogenic effects of land use and land management from natural driver’s impacts. 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 cycle, whereas others are inherited under different conditions and reflect past land-use.

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

Keynote speaker will be David Powlson, Rothamsted Research, UK: "Carbon sequestration in soils – has the potential for climate change mitigation been over-stated?"

This session will be co-sponsored by the FP7 project GHG-Europe.