The reserves of carbon in vegetative and microbial biomass of Siberianecosystems

摘要

Extensive factual data on the reserves of labile organic carbon in the vegetative matter and microbial biomass of nonforest ecosystems of Siberia have been analyzed. It is shown that the highest reserves of labile carbon are typical of virgin and mown meadow ecosystems in the flood plains of Western Siberia. The lowest reserves of labile carbon are found in cereal agrocenoses of central and Eastern Siberia. The reserves of microbial biomass vary by an order of magnitude (from 50 to 500 g/m(2)) and depend on the type of land use. They increase with an increase in the degree of soil moistening and heat supply. Maximum changes in the reserves of labile carbon take place upon the transformation of natural forest and steppe cenoses into agrocenoses. Within 200 years of soil cultivation in Western Siberia, the net primary production of lands occupied by agrocenoses has decreased by three times; the reserves of vegetative matter, by six times; and the reserves of soil organic matter (0-20 cm), by 30%.