The Fraction of Carbon in Soil Organic Matter

A collation of datasets and derived carbon metrics is provided for soil samples with data on total soil carbon, soil organic carbon (SOC) and soil organic matter (SOM) for soil samples from Europe and globally, permafrost regions and global seagrass sediments. Soils were sampled to different depths.SOC and SOM were used to calculate derived parameters such as foc (the fraction of SOC in SOM) and SOM content was used to define mineral (<20% SOM) and organic (>20% SOM) soils. The provided dataset was used to explore foc as a national-scale soil process indicator. Understanding the relationship between SOC and SOM fractions provides insight into SOM decomposition and SOC storage potential. Here we show an intriguingly tight relationship between the fraction of SOC in SOM (denoted as Foc). By compiling 14 datasets and 9503 measurements from across Europe and globally we analysed (Foc) across mineral and organic soils, which fell between 0.38 and 0.58.