Pools and fractions of organic carbon in soil: structure, functions and methods of determination

Abstract

The separation of soil organic matter (SOM) into pools and fractions allows to understand the nature and functions of SOM as well as to characterize its quality, composition and properties. The study presents an analysis of approaches, methods and results of determining various pools and fractions of SOM using the gray forest soil (Haplic Luvisol) under contrasting types of land use (Moscow region, Russia). Conservative properties and storage functions of SOM matter were proposed to be estimated by its granulometric and densimetric pools, and dynamic properties and emission functions - by its microbial and potentially mineralizable pools. It was shown that the ratio of different pools in the SOM composition depends on the type of land use and it is controlled by the composition and amount of plant materials entering into soil. The separation of structural and process pools, the determination of their sizes and ratios should be considered an essential stage in the programs for monitoring the quality and functions of SOM matter and carbon sequestration processes.