冀北承德地区土壤生源要素生态化学计量与空间分异特征

土壤生源要素生态化学计量和空间分异特征对指导土地利用优化具有重要意义。以京津冀生态屏障区组成部分的承德市为研究区，采集1597件土壤样品，运用地统计学、全局Moran′s I指数、克里金插值和冗余分析等方法对承德全域主要土壤生源要素的空间分异特征及其影响因素进行了系统分析。结果表明，承德市表层土壤生源要素全钾(STK)、有机碳(SOC)、全氮(STN)、全磷(STP)和全硫(STS)平均含量分别为21.962 g/kg、18.826 g/kg、1.168 g/kg、0.587 g/kg和0.193 g/kg。垂向分布上STN、SOC和STS含量总体随深度增加而降低，STK和STP垂向分异受成土母质控制，高地质背景区STK和STP含量随深度增加逐渐升高。SOC和STN含量显著相关，空间耦合程度高，C:S与SOC含量显著正相关，C:N和C:S空间分布稳定，土壤生源要素的化学计量比主要受SOC含量控制。SOC空间自相关极显著，空间分异受结构性因素控制；STK空间自相关程度较高，分布稳定；STP空间自相关较显著，分布异质性较大；STS空间自相关相对最弱，受人为活动影响较明显。SOC和STN空间...

Spatial variation of ecological stoichiometry characteristics of soil biogenic elements in Chengde City, northern Hebei Province, China

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.