Geographic and genetic features of the humus status of gray forest soils

Statistically substantiated parameters of the humus status of virgin and cu ltivated gray forest soils have been obtained from the analysis of publishe d data. The peculiar features of bioclimatic subtypes of gray forest soils and the family of gray forest soils developing from Permian red-earth depos its are revealed. The zonal-provincial and regional lithological peculiarit ies of the humus status of gray forest soils are specified. Their importanc e for the diagnostics and classification of soils and pedoclimatic zoning i s shown. The reserves of organic carbon in the gray forest soils of the for mer Soviet Union and Russia are evaluated, as well as the rate of organic c arbon sequestration in deep soil horizons.