Assessment of Carbon Stock and CO2 Production Potential for Soils of Coniferous-Broadleaved Forests

Abstract

—The assessment of carbon stocks in soils of coniferous and broadleaved forests, agrocenoses, fallow lands, and floodplains has been performed for the territory of the Chashnikovo Agrobiological Station of Moscow State University. The typology of litter horizons, the contents of plant detritus in the them, and the ratio of the thicknesses of litter subhorizons have been determined as indicators of the organic matter decomposition intensity. For mineral soil profile, total organic carbon stocks in the layers of 0–30 and 0–100 cm layers and the stock of biologically active carbon in the layer of 0–20 cm layer have been determined. Maximum organic matter accumulation in litters and moderate accumulation in mineral profile is typical of soddy-podzolic soils (Retisols) under coniferous forests. The litter carbon stocks in spruce forests differ by almost an order of magnitude depending on the position in the tessera. Minimum carbon accumulation in litters is characteristic of the soils of upland and floodplain meadows. Alluvial soils of floodplain meadows are characterized by the highest stock of total carbon, as well as carbon of biologically active soil organic matter. The potential of CO2 production by soil determined the structural and functional litter characteristics and the stock of biologically active organic matter in the upper (0–20 cm) soil layer depend on several factors: vegetation type, hydromorphism degree, and agricultural use at present and in the past. Soils of coniferous forests in comparison with soils of broadleaved forests are characterized by lower rates of litter decomposition due to the biochemical features of plant remains and are assumed to have a lower potential for CO2 production. Soils of natural herbaceous ecosystems, especially floodplain meadows, are characterized by the maximum potential production of carbon dioxide due to intense decomposition of plant residues and high stock of biologically active organic matter carbon.