Impacts of 21-year field warming on soil erodibility in the Qinghai-Tibetan Plateau, China

•A field warming experiment took place over 21 years on the Qinghai-Tibetan Plateau.•Warming increased the erodibility of topsoil but this effect weakened with depth.•Microbial activity and aboveground plant biomass decreased.•There were differences in the erodibility of shrubland and grassland soils. Terrestrial ecosystems are significantly impacted by global warming. To determine the effects of long-term warming on soil structure and erodibility in the Qinghai-Tibetan Plateau (China), a 21-year field warming experiment was conducted, where the soil response to temperature changes was investigated for two vegetation types (shrubland and grassland). The measured parameters included the fractal dimension (Dv) of aggregates, mean weight diameter (MWD), geometric mean diameter (GMD), multifractal dimensions of particle size distribution [capacity dimension (D0), information dimension (D1), information dimension/capacity dimension ratio (D1/D0), and correlation dimension (D2)], and soil erodibility value (K). The results show that warming significantly increases the erodibility of the topsoil (0–2 cm). Among them, the larger particles (0.2–2 mm aggregates, sand) decreased, the K factor, Dv, and multifractal dimension (D0) increased, and the MWD and GMD of the soil aggregates decreased. Long-term warming affected the amounts of soil organic carbon, total nitrogen, and total phosphorus. Furthermore, warming weakened microbial activity and led to a reduction in the aboveground biomass of plants. With increasing soil depth, the effect of warming on the erodibility of underlying soil (2–12 cm) gradually weakened. Warming exhibited different effects on the erodibility of the shrubland and grassland because of their different soil aggregates and particle size distributions. These results confirm that long-term warming has obvious soil layering effects on different soil depths. Soil properties, plants, and microorganisms respond to warming and have direct or indirect effects on soil erodibility. The results of this study provide important insights into changes in soil structure and erodibility at high altitudes, especially under global warming.