Soil Organic Carbon Pools: Isolation Methods, Sizes, and Ratios

A scheme for the subdivision of soil organic matter (SOM) into structural, process-related, and functional pools has been developed. Particulate organic matter (CPOM) and mineral-associated organic matter (CMAOM) referred to the SOM structural pool group contain, on average, 28 and 70% of total soil organic carbon (Corg), respectively. The carbon content is 4.6, 1.4, and 81% in the process-related pools of potentially mineralizable organic matter (CPM), microbial biomass (CMB), and chemically oxidizable organic matter (COX), respectively. The structural and process-related carbon pools correlate with each other and with Corg in terms of size. Three functional SOM pools (active, slow, and passive) contain approximately 5, 76, and 19% Corg, respectively.