Fig. 4

Spatial and vertical distributions of the SOC stock on the Qinghai Plateau. Spatial distributions of the estimated SOC stock at 0–200 cm depth (a) and the relative proportion of estimated SOC stock at 0–30 cm depth (b), (c) the relative proportions (Mean + SD) at different soil layer depths in six vegetation types on the Qinghai Plateau. The relative proportion is represented by the proportional contribution of each layer to the total SOC stock at a depth of 200 cm. The SOC stock was estimated by the model considering the paleoclimatic factors (Model_PC). SOC represents soil organic carbon