A detailed understanding of temporal and spatial dynamics of soil organic carbon is becoming of increasing global importance, as soil organic carbon is directly linked to greenhouse gas emissions and soil carbon sequestration. Additionally, soil organic carbon is a vital element in soil health, affecting many essential soil functions. Therefore, the importance of soil inventories at various scales, from national to pan-European, for quantifying soil organic carbon dynamics has increased. Consequently, numerous spatial and spatio-temporal predictions of soil organic carbon have been produced in recent years. However, it is currently unknown to what extent these inventories and their derived predictions align in terms of the magnitude and direction of soil organic carbon change.
Using data from repeated soil inventories at national and regional scales and data from LUCAS, we compare trends in soil organic carbon across Europe, focusing on mineral soils of agricultural land. For selected regions, the trends of soil organic carbon change are also compared to estimates from the recent maps of soil organic carbon density trends produced by the AI4SoilHealth project. These comparisons are somewhat limited due to differences in sampling and calculation methodology between countries, varying definitions of land uses, and differences in the time periods covered by the various data sources. Overall, the comparison of soil organic carbon dynamics across Europe is complex, and increased collaboration between countries can improve comparability of results and improve alignment of the estimates of soil organic carbon dynamics at both national and European scales.

Authors: Laura Sofie Harbo, Ali Sakhaee, Florian Schneider