Physical mechanisms of carbon stabilization in soils (a review)

Stabilization of soil organic matter (SOM) is a key factor for maintaining fertility and reducing carbon dioxide emissions from the soil into the atmosphere during agricultural activities. A relevant scientific and practical area of research is the development of cultivation technologies that provide optimal physical properties of the soil for the plant growth and development, as well as for the vital activity of the soil microbiome. Understanding the physical mechanisms that regulate the carbon (C) balance of soils and the transformation of organic matter is therefore essential. This paper is aimed to provide an overview of existing concepts concerning the physical factors and mechanisms of C stabilization in soils, and to describe the physical processes regulating the C cycle in soils. The relationship between the SOM transformation processes and the physical factors of soil formation is shown through the modern understanding of the concept of the structural organization of soils, since SOM plays a key role in the formation of the soil structure and determines its quality. The development of methods and methodology of soil physics is analyzed and the most promising research areas for understanding the C cycle are considered. The review pays special attention to the influence of physical properties of soils on the growth and development of plants, as the main source of incoming organic matter and a necessary condition for sequestration of C by soils. The existing limitations in using of soil physical parameters in mathematical modeling of C stabilization processes are also considered.