PLA平铺沙障对沙丘土壤颗粒分形特征的影响

Effects of PLA Sand Barriers on Soil Fractal Dimension

采用室外调查与室内分析相结合的方法,统计分析了毛乌素沙地PLA沙障铺设5年后的土壤颗粒粒径组成、分形维数及其与土壤砂粒(】0.05 mm)、粉粒(0.05~0.002 mm)和黏粒(【0.002 mm)含量的之间的关系。结果表明:研究区沙物质颗粒主要以粒径大于0.05 mm的细沙、极细沙为主。设置PLA沙障后,导致沙丘中粗沙含量减少,黏粒物质增加。沙障规格对土壤分形维数的影响表现为规格越小,土壤分形维数越大。沙丘表层分形维数与砂粒含量(】0.05 mm)呈极显著的负相关关系,而与黏粒含量呈极显著的正相关关系。该地区颗粒分形维数的临界粒径为0.05 mm粒径物质,低于0.05 mm的颗粒含量越多,分形维数越高,反之则越低。设置PLA沙障后,黏粒物质聚集和沙粒物质的降低共同导致分形维数的增加。

In this paper, using the combining of field investigation and laboratory analysis of the method, the soil particle size distribution, the fractal dimension and the relationships were analyzed between the fractal dimension of soil particle size, sand content( >0.05 mm), silt content(0.05 ~ 0.002 mm) and clay content(<0.002 mm) for PLA sand barrier. Results showed that: Sand particles of study area were mainly fine sand whose diameter size were greater than 0.05 mm. Due to PLA sand barrier, coarse sand content reduced and clay content increased. The smaller size sand barrier, the greater soil fractal dimension. There was a significant negative correlation between fractal dimension and sand content(>0.05 mm) and a significant positive correlation between fractal dimension and sand content. 0.05 mm diameter is the critical particle size for reflecting fractal dimension of mobile dune, the more content of particle with diameter lower than 0.05 mm size, the higher fractal dimension. Both the increase of particle content with diameter <0. 05 mm and decrease of particle content with diameter >0.05 mm caused the increase of fractal dimension of soil particle size after setting up PLA sand barriers.