Spatiotemporal dynamics and associations of soil organic carbon and total nitrogen in the Qilian Mountain Grasslands

Understanding the coordinated changes in soil carbon and nitrogen is essential for evaluating ecosystem responses to environmental change, particularly in ecologically fragile alpine regions such as the Qilian Mountains. In this study, the denitrification-decomposition (DNDC) model was used to assess the spatiotemporal dynamics of soil organic carbon density (SOCD) and total nitrogen density (STND) in the 0-30 cm soil layer from 1975 to 2024. The results revealed that SOCD and STND were higher i