Microorganisms in the processes of transformation of soil organic matter

Abstract

Goal. To substantiate the role of microorganisms in the processes of transformation of soil organic matter, and the dependence of the functional orientation of the microbiota on the factors of influence on destructive and synthetic processes in soils of agrocenoses. Methods. Theoretical and analytical approach: analysis — to evaluate and compare the results of domestic and foreign studies; synthesis and generalization — to systematize existing points of view on the participation of microbiota in the processes of soil fertility formation. Results. The leading role of microorganisms in the processes of mineralization — synthesis of organic matter and sequestration of carbon in soils was substantiated. New views on the essence of organic matter of soil (OMS), features of its storage, and transformation were considered. Among the factors of influence on destructive and synthetic processes, the aggregate condition of soils, observance of crop rotation, receipt of exogenous organic matter as the basis of constructive and energy metabolism of soil microbiota, formation of microbial biomass, sequestration of carbon, use of mineral fertilizers, first of all nitrogen, were allocated. The systemic use of mineral nitrogen in crop cultivation technologies can lead to the mineralization of OMS, since plants use mineral nitrogen from fertilizers at the level of 35–50%. When the carbon available for microorganisms in the soil is represented only by root and post-harvest residues, a stoichiometric imbalance occurs between nitrogen not assimilated by plants and readily available carbon. However, providing the soil with fresh organic matter with a wide C:N ratio in the appropriate amount can neutralize the negative effect of mineral nitrogen and reorient the direction of the processes of transformation of organic matter. Theoretically, any rate of mineral nitrogen can be transformed into organic compounds and converted to a safe, non-superfluous form if there is readily available carbon in the soil. To increase carbon sequestration, it is necessary to provide the soil not only with fresh organic matter, but also with other biogenic elements, primarily mineral nitrogen. Conclusions. Transformation of OMS is a multi-organized process in which microorganisms play a key role.