Assessment of Carbon Stock and СO₂ Production Potential for Soils of Coniferous-Broad-Leaved Forests

Within the territory of MSU Agrobiostation “Chashnikovo”, assessment of carbon stock for soil, typical for coniferous-broad-leaved forests subzone – coniferous forests, small-leaved forests, agrocenoses, fallow lands and floodplain meadows – was given. The next indexes were studied for litters: typology, stock, detritus content and ratio of sub-horizons thickness (deposit) – these indexes are indicators of organic matter decomposition intensity. For mineral soil profile, the assessment of general organic carbon stock in 0–30 and 0–100 cm layers, as well as stock of biologically active carbon in 0–20 cm layer (by calculation according to the content of total carbon), are given. Maximum organic matter accumulation in litters and moderate accumulation – in mineral profile, was obtained for coniferous forests soddy-podzolic soils. The litter carbon stock value in spruce forests differ by almost 10 times, depending on location in tessera. Minimal carbon accumulation by litters is obtained for meadow ecosystem soils – upland meadows as well as flood-plain meadows. Alluvial soils of flood-plain meadows are characterized by highest stock of general carbon, as well as carbon of biologically active soil organic matter. Potential of CO₂ production by soil, determined by data, including structural and functional litter indexes and organic matter biologically active carbon stock (0–20 cm layer), depends on combination of row of factors: vegetation type, hydromorphism degree, and agricultural use character in present or past. Coniferous forest soils comparing with small-leaved forest soils are characterized by less rate of litter decomposing due to plant remains biochemical features, thereby these soils are assumed to less CO₂ production potential. Soils of natural grass ecosystems, especially flood-plain meadows, are characterized by maximal potential production of carbon dioxide, resulting from intensive plant residues decomposition and high stock of biologically active organic matter carbon.