Abstract:

By investigating the distributional pattern of soil carbon with various properties in two types of soil profile in a subtropical forest ecosystem, the primary soil and warp soil were analyzed and explored for their important roles in the process of soil carbon cycle. We conducted the study in a subtropical mountainous moist evergreen broad-leaved forest in the Ailao Mountains of Yunnan Province, took the primary soil in the forest area with high altitude and the warp soil in the shrubby-meadow area with low altitude as sampling sites, collected soil samples in different soil layers along the two types of soil profile, and focused on the vertical distribution pattern of soil carbon with various properties including soil total organic carbon, labile organic carbon, microbial biomass carbon, dissolved carbon and water dissolved carbon in the soil layers with most plant roots (0-45 cm). The results show that the concentrations of all determined soil carbon with different properties decrease exponentially along the two types of soil profile. The concentrations of soil total organic carbon, labile organic carbon and water dissolved carbon in the warp soil are statistically higher than those in the primary soil; the concentration of soil microbial biomass carbon is not statistically different between the two types of soil; and the concentration of dissolved carbon in the warp soil is significantly lower than that in the primary soil, indicating that the primary and warp soil play different roles in storing and circulating soil carbon with different properties in the subtropical mountainous moist evergreen broad-leaved forest ecosystem in the Ailao Mountains. The results adequately demonstrate that although the vertical distribution pattern of soil carbon with various properties in different soil profiles of the same subtropical forest ecosystem is consistent, the average storage has obvious spatial heterogeneity. The paper could provide a new theoretical basis and research direction for the estimation of soil carbon with different properties in the global tropical and subtropical forest ecosystems and the study on soil carbon cycle in different types of soil profile.

Key words: soil total organic carbon, soil labile organic carbon, soil microbial biomass carbon, soil dissolved carbon, soil water dissolved carbon, subtropical evergreen broad-leaved forest in the Ailao Mountains, primary soil, warp soil