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运用土壤粒径质量分布原理与分形学理论,以黄河三角洲贝壳堤岛的3种植被类型为研究对象,以裸地为对照,测定分析土壤颗粒分形维数、粒径组成和水分物理参数,探讨不同植被类型的土壤颗粒分形特征及其影响因素。结果表明:贝壳砂土壤中粗砂粒含量最高;其次是细砂粒,而石砾和粉粘粒含量较低。灌木林地和草地具有降低石砾、粗砂粒,增加细砂粒和粉粘粒含量的作用。不同植被类型土壤颗粒分形维数均值在1.5845—1.9157之间,大小依次为酸枣林、杠柳林和草地,表层高于20—40cm土层。酸枣林、杠柳林及草地0—40cm土壤容重均值分别比裸地低23.87%,14.51%和10.47%;总孔隙度均值分别比裸地增加16.96%,16.71%和1.31%。植被恢复措施对贝壳砂表层的孔隙结构、疏松程度改善较好,草地及灌木林地的蓄水性能均表现为0—20cm高于20—40cm。土壤颗粒分形维数与粉粘粒含量、毛管孔隙度、总孔隙度、饱和蓄水量、吸持蓄水量等呈极显著正相关,与细砂粒含量呈显著正相关,与粗砂粒含量和容重呈极显著负相关,与石砾含量、非毛管孔隙度、滞留蓄水量的相关性不大。从土壤分形维数及其水分生态特征来看,贝壳堤岛3种植被类型的改良土壤物理性质及蓄水保土功能表现为灌木林好于草地,其中酸枣林好于杠柳林,0—20cm好于20—40cm土层。
Based on the principle of mass distribution of soil particle size and fractal theory, taking the three vegetation types of shell island in the Yellow River delta as the research object, the fractal dimension, the particle size and the physical parameters of water were measured and analyzed with bare land as reference Fractal Characteristics of Soil Particles and Its Influencing Factors in Different Vegetation Types. The results showed that the content of coarse grit in the shell sand was the highest, followed by the fine grit, while the content of gravel and silt was low. Shrubbery and grassland have the function of reducing the gravel, grit and increasing the content of fine sand and silt. The average fractal dimension of soil particles in different vegetation types ranged from 1.5845 to 1.9157, followed by the jujube forest, barbarian forest and grassland, and the surface layer was higher than the 20-40 cm soil layer. The mean values of soil bulk density of 0-40cm in jujube forest, barbarian forest and grassland were 23.87%, 14.51% and 10.47% lower than those in bare soil, respectively. The average total porosity increased by 16.96%, 16.71% and 1.31% respectively. The measures of vegetation restoration improved the pore structure and looseness of shell sand better, and the water storage performance of grassland and shrub forest showed 0-20cm higher than 20-40cm. The fractal dimension of soil particles is significantly and positively correlated with the content of silt, capillary porosity, total porosity, saturated water storage, holding water storage and so on, and has a significant positive correlation with fine sand content, The bulk density was extremely significantly negatively correlated with the gravel content, non-capillary porosity and retention water content. According to the fractal dimension of soil and its water ecological characteristics, the improved soil physical properties and water storage and soil conservation function of the three vegetation types of shell embankment Island are better than grassland in the shrub forest, 20cm better than 20-40cm soil layer.