ABSTRACT
The rate of organic carbon accumulation in soils and of the stability of humus substances remains a disputable problem. Evaluation of the humus accumulation rate has been made using the chronosequence approach; i.e., soils of different ages in similar topographic and lithological conditions have been studied. Soil chronosequences were investigated in the forest-meadow subalpine zone of the Elbrus region, in Caspian semideserts, and in Stavropol' Uplandsteppe. Soils study objects were chosen in such a way that the age of their parent material was known for natural substrates or for man-made ones Investigations of soils' ingredients of microcatenas of different ages in the Caspian semidesert revealed high rates of topogenic differentiation of soil humus status and development of humus profile. Humus of soils buried under funeral mounds is much poorer in humates in comparison with humus of the most mature soils on the mound. The quality of buried soils' humus changes with the depth of anthropogenic deposits above the soil.
