Regional Specifics of the Carbon Storage Formation in the Haplic Cambisols in the South of the Primorskii Krai

The stocks of total and organic carbon in the soils of two types of natural forest biogeocenoses (Korean pine and broadleaved stands) are determined based on the study of physical and chemical properties, including the content and distribution of carbon and nitrogen in the profiles of Haplic Cambisols in the south of the Primorskii krai (Russia). These are slightly acidic soils ( $${\text{p}}{{{\text{H}}}_{{{{{\text{H}}}_{{\text{2}}}}{\text{O}}}}}$$ 5.8–6.6) with a low content of carbonates (0.048–0.066%), contrasting increase in density (0.68–2.23 g/cm3), and a decrease in the content of fine earth (92.5–8.2%) downward the profile. The carbon and nitrogen contents in forest litter vary in the range of 32.4–48.3% (C) and 1.5–3.6% (N) in the OL subhorizon and 20.6–34.6% (C) and 1.1–2.0% (N) in the OFH subhorizon. Intensive mineralization of abundant plant litter contributes to an active input of carbon and nitrogen into the AY horizon (5.6–14.3 and 0.5–1.0%, respectively); the content of the elements sharply decreases with depth. The highest potential for carbon accumulation and stabilization in the soil profile is typical of Haplic Cambisols under Korean pine stands with maximum stocks of both Ctot (169.6 t/ha) and Corg (169.4 t/ha) in the profile. A comparison of the intensities of forest litter decomposition and the input of C-containing compounds to the underlying horizons of Haplic Cambisols under elementary biogeoareas (EBGAs) in Korean pine stands suggests more intensive processes in the Haplic Cambisols under linden mixed-shrub EBGA than under Korean pine EBGA without vegetation in the ground cover. The Ctot and Corg stocks in the Haplic Cambisol profile under broadleaved forest match the worldwide average carbon stocks in the soils under deciduous forests of temperate latitudes and amount to 138.8 and 138.6 t/ha, respectively.