宁夏平原不同土地利用类型土壤颗粒组成及分形特征

Soil Particle Size Distribution and Fractal Characteristics of Different Land Use Types in the Irrigation Area along the Yellow River in Ningxia

土壤粒径的组成与分布特征,可为区域土地利用和质量评价提供科学依据。利用颗粒体积分形理论,分析了宁夏平原土壤颗粒组成、不同土地利用类型土壤颗粒组成及分形特征。研究结果表明,宁夏平原不同土地利用类型土壤颗粒组成较为均匀,土壤颗粒组成主要以粉粒和砂粒为主,其中:黏粒和粉粒含量由高到低依次为农田、道路边坡、防护林、荒地,而砂粒含量由高到低依次为荒地、防护林、道路边坡、农田;研究区域分形维数在1.91~2.94之间,分形维数由大到小依次为农田、道路边坡、防护林、荒地;土壤颗粒组成与分形维数呈现显著线性相关,黏粒与粉粒含量对分形维数有重要影响。土壤不同粒径占比与分形维数相关性表明,分形维数更易受到土壤粒径中占比较高的颗粒的影响。

The composition and distribution characteristics of soil particle size can provide scientific basis for regional land use and quality evaluation.Based on the fractal theory of particle volume,we analyzed the soil particle composition and the soil particle size distribution and fractal characteristics of different land use types in the irrigated areas along the Yellow River in Ningxia.The results of the study showed that the soil particle size distribution of the four land use types in the irrigation area along the Yellow River in Ningxia was relatively uniform,and the soil particle size distribution was mainly silt and sand;the clay and silt content was as follows:farmland,road slope,protection forest,wasteland;the sand content was as follows:wasteland,protection forest,road slope,farmland;the fractal dimension ranges from 3.04 to 1.91,and the order of fractal dimension was as follows:farmland,road slope,protection forest,wasteland.Soil particle size distribution was linearly correlated with fractal dimension,which was mainly determined by clay and silt content.The correlation between the proportion of different soil particle size and fractal dimension indicates that the fractal dimension is more easily affected by the particles with higher proportion in PSD.The results can provide reference value for regional land management.