This dataset (map) (2016) shows the Soil Organic Carbon (SOC) saturation capacity, expressed as the ratio between the actual and the potential SOC stock in each pixel. Values close to 0 indicate a great potential of soil to store more carbon.
How to cite
European Commission, Joint Research Centre (JRC) (2016): Soil Organic Carbon - Saturation Capacity in Europe. European Commission, Joint Research Centre (JRC) [Dataset] PID: http://data.europa.eu/89h/jrc-esdac-38