文档介绍：文章编号:1008-181X(2000)04-0263-03
中国土壤颗粒组成的分形特征研究
李德成,张桃林
(中国科学院南京土壤研究所,江苏南京 210008)
摘要:以土壤颗粒组成数据为基础,分析了我国土壤颗粒组成的分形维数。结果表明,不同质地的分形维数存在一定的差异,分形维数随土壤质地的变细而增大;由北至南、由西向东和由西南至东北,我国主要地带性土壤的分形维数逐渐递增;成土母质对土壤质地分形维数有很大影响,易风化母质上发育的土壤质地分形维数高于难风化母质上发育的土壤。
关键词:分形维数;土壤质地;颗粒组成;地带性土壤;成土母质
中图分类号: 文献标识码:A
Fractal Features of Particle Size Distribution of Soils in China
LI De-cheng, ZHANG Tao-lin
(Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China)
Abstract: This paper analyzed the fractal features of particle size distribution (PSD) of soils in China. The results showed that: various soil textures had different fractal dimensions, the fractal dimensions of PSD of soils increased with soil texture fining; from west to east, from north to south and from southwest to northeast,there were decreasing tendencies in the fractal dimensions of PSD of soils; and the parental materials had evident influences on the fractal dimensions of PSD of soils.
Key words:fractal dimension; particle size distribution of soil; soil texture
Mandelbrot创立的分形论已成为描述自然界中复杂和不规则几何形体一个有效工具。分形论在地学和土壤制图学研究领域也得到了一定应用[1,2]。研究表明土壤是具有分形特征的系统[3~5]。有研究利用粒径的重量分布来描述土壤颗粒组成(Particle Size Distribution,简记为PSD)或团粒组成(Aggregate Size Distribution,简记为ASD) 的分形维数[5~7]。利用这一方法,依据中国土壤颗粒组成的基础资料[8~9],本文分析了我国土壤质地的分形维数特征。
1 土壤颗粒组成的分形维数D的计算原理[5~7]
土壤中由大于某一粒径di(dI >di+1,i = 1,2,…)颗粒构成的体积可由类似Katz的公式表示:
(1)
(1)式中,