Сarbon Stock in Sandy and Loamy Soil of Coniferous-Deciduous Forestsat the Different Stages of Successions
A comparative assessment of carbon stock in the loamy soils (Albic Retisols) of coniferous-deciduous forests of the Moskvoretsko-Okskaya region and sandy soils (Albic Podzols) of the Bryansk region was estimated. The carbon stock in soil was related to the particle size distribution in mineral soil horizons and biotic factors, such as quality of litter and activity of earthworms. The forests on sandy soils were characterized by high carbon stocks in the litter, which was explained by low biomass of earthworms. The carbon content was significantly higher in the mineral horizons of loamy soils, characterized by a high proportion of fine particles. The carbon stocks in the litter and mineral horizons of loamy and sandy soils turned were comparable, except for sandy soils of mixed forests due to higher proportion of fine particles. In the course of succession of coniferous-deciduous forests on loamy soil, carbon accumulation in litter was high only at the late stage, due to the high input of spruce needles. The carbon stock in the humus horizons of loamy soils varied due to changes in their density, which was regulated by earthworms. When comparing different succession stages/types of forests on sandy soils, it was found that the carbon stock in the litter of pine forests at the early stage of succession was significantly higher than those of mixed and broadleaved forests. Trends in carbon accumulation in the mineral soil horizons of sandy soils were mainly explained by their thickness, which was related to the amount of precipitation regulated by woody plants.