山西省森林土壤因子空间变异特征

为了揭示山西省森林土壤因子的空间分布特征,为评价森林土壤肥力提供参考,为森林可持续经营提供技术支撑,并为区域林业发展规划的制定提供依据。基于山西省297块样地的土壤采样检测数据,包括森林土壤碱解氮、全氮、有机质、速效磷、全钾、pH、含水量7个因子,利用GIS进行趋势分析、半变异函数模型选取,利用克里金插值法揭示森林土壤因子的空间变异特征。结果表明：全氮、碱解氮、pH的最优模型为高斯函数模型;速效磷、全钾的最优模型为指数函数模型;有机质、含水量的最优模型分别为三角函数模型和球面函数模型。利用克里金插值法绘制了各森林土壤因子的空间分布图,揭示了山西省森林土壤因子的分布特征。山西省森林土壤因子均有明显的空间分异特征：碱解氮、全氮、有机质含量相对较高的多集中在省境主体山脉沿线的中高山地区;全钾含量整体表现较为丰富;含水量表现出明显的东南多西北少的差异;速效磷作为一种瞬时变量,在空间分布上比较杂乱;pH的空间变异显示,山西省整体森林土壤呈弱碱性,朔州市部分地区森林土壤表现为强碱性,可作为盐碱地研究典型区域。

Spatial Variability Characteristics of Forest Soil Factors in Shanxi Province

To reveal the spatial distribution characteristics of forest soil factors in Shanxi Province, provide reference for the evaluation of forest soil fertility, technical support for sustainable forest management, and a basis for the establishment of forestry sustainable development policy, based on the soil sampling and testing data of 297 sample spots in Shanxi, the study used GIS techniques to do trend analysis and select the optimal semi-variogram model of 7 factors of forest soil, including alkali-hydrolyzed nitrogen, total nitrogen, organic substance, available phosphorus, total potassium, pH and water content. Then, Kriging interpolation was adopted to analyze the spatial variability characteristics of the forest soil factors. The results show that: the optimal semi-variogram model of total nitrogen, alkali-hydrolyzed nitrogen and pH is Gaussian function model; that of total potassium is exponential function; that of the organic matter and water content is trigonometric and spherical function, respectively. Finally, we used Kriging interpolation method to map the spatial distribution of the forest soil factors, to display the distribution characteristics of them in Shanxi directly. The spatial differentiation characteristics of the forest soil factors in Shanxi are obvious. For alkali-hydrolyzed nitrogen, total nitrogen and organic substance, the relatively high contents are mainly concentrated in the mid-high mountainous area along the main mountain range in the province. The content of total potassium is relatively rich. The water content shows obvious difference of more in southeast and less in northwest. As an instantaneous variable, the spatial distribution of available phosphorus is rather disordered. The spatial variability of pH indicates that the whole forest soil in Shanxi is weakly alkaline, particularly in some areas of Shuozhou, the forest soil is strong alkalinity, which could be used as the typical area of saline-alkali land in research.