Organic carbon mineralization of biological soil crusts and subsoils in the revegetated areas of the southeast fringe of the Tengger Desert

As an effective measure to curb land degradation in desert regions, revegetation plays a key role controlling the colonization and settlement of biological soil crusts(BSCs), which would modify the processes of soil formation and carbon cycle. Recently, mineralization of BSCs and their subsoils along with the succession of sand-fixing vegetation were still poorly understood, which may to a certain extent limits the accurate estimation of the ecological effects of sand-fixing vegetation. In this study, the carbon mineralization of BSCs and the 0-5 cm soil under BSCs in the vegetated areas at different revegetation ages in the southeastern edge of the Tengger Desert were investigated by using the indoor-incubation-alkali-absorption method, and the relationships between the carbon mineralization rates and water treatments and soil physicochemical properties were analyzed. The results showed that: the instantaneous(IR), maximum(MR) and average mineralization(AR) rates and the amount of cumulative C release(CCR) of BSCs and subsoils all increased with the increasing stand age, and they were significantly greater in BSCs than those in the subsoils(P