Аннотация:The paper presents research data on profiles of fatty acids in typical chernozems of various use. It is shown that organic matter degradation in typical chernozems is accompanied by depletion of fatty acids, while its accumulation results in an increase in their diversity. In this regard, the composition of fatty acids in soil profiles makes it possible to classify soils with respect to predominant organic matter transformation processes. It has been revealed that the distribution of fatty acids in soil aggregates of different sizes is inhomogeneous in uncultivated chernozems, but homogeneous in developed soils. Eicosapentaenoic acid, which is a moiety of microalgae, and dihomo-gamma-linolenic acid, which is synthesized by Mortierella fungi, can be considered biomarkers of the transformation of cultivated typical chernozem into abandoned land.