Abstract:The ecological stoichiometry and spatial variation characteristics of soil biogenic elements are important to the optimization of land use and water conservation. A total of 1597 soil samples were collected from the Chengde City, a part of Beijing-Tianjin-Hebei ecological barrier area and analyzed for soil total nitrogen (STN), soil total phosphorus (STP), soil total potassium (STK), soil total sulfur (STS), soil organic carbon (SOC), and pH. The spatial distribution, stoichiometric characteristics of soil biogenic elements and influence factors were systematically analyzed by multivariate methods including geostatistics, redundancy analysis and global Moran's I index, Kriging interpolation based on GIS. The results showed that the average content of topsoil biogenic elements followed an order of STK>SOC>STN>STP>STS, with the value of 21.962 g/kg, 18.826 g/kg, 1.168 g/kg, 0.587 g/kg and 0.193 g/kg, respectively. The contents of STN, SOC and STS decreased with depth in typical soil profiles. The vertical distribution of STP and STK was dominated by the type of parent rock, while the STK and STP content increased with depth in soil profiles of those parent material with high background of potassium and phosphorus. The SOC, STN and C:N ratio showed a significantly positive correlation. The spatial distribution of SOC and STN was highly coupled. The stoichiometry of soil biogenic elements was dominated by the SOC. Compared with other elements, the SOC had the highest spatial autocorrelation and its spatial variability was dominated by structural factors. The STK and STP showed significantly spatial autocorrelation, but the spatial variability of STP was significantly higher than that of other elements. The STS showed the weakest spatial autocorrelation and its spatial variability was obviously affected by human activities. The spatial variation of SOC and STN was mainly dominated by land use type and Normalized Difference Vegetation Index (NDVI) value, and the SOC and STN content in forest land with high vegetation coverage was the highest. The spatial variation of STK, STP and STS was affected by both structural and random factors. The dominant structural factors were soil parent material type and rock weathering process. The STK content was higher in the parent material area of intrusive and volcanic rocks, the STP content was higher in hornblende diorite and gneiss area, and STS content was higher in hornblende diorite, gneiss and carbonate area. The industrial and agricultural activities were important driving factors of the spatial variation of soil phosphorus and sulfur. The ecological stoichiometry of soil biogenic elements was of great significance to guide the conservation of water and soil, protection of water environment, and application of fertilizer reasonably.