四种粒径分级制度对土壤体积分形维数测定的影响

Effects of Soil Particle Size Classification System on Calculating Volume-based Fractal Dimension

为揭示粒径分级对土壤体积分形维数测定的影响,采用激光衍射技术测定毛乌素沙地风沙土粒径组成,基于中国制、前苏联制、美国制和国际制4种不同粒径分级方法计算土壤体积分形维数.研究结果显示,(1)研究区土壤质地较粗,土壤颗粒组成以砂粒为主,占总体积的90%以上,而黏粒、粉粒含量相对较少;土壤体积分形维数大小排序为前苏联制(DSU)>中国制(DCHN)>国际制(DINT)>美国制(DUS);(2)DCHN、DUS和DINT与土壤粘粒、粉粒和砂粒含量线性回归拟合效果良好,且相关性极显著(P<0.01);DSU与土壤粉粒和砂粒含量相关性显著(P<0.05),但线性回归拟合效果较差;(3)DCHN、DUS和DINT之间呈极显著正相关关系(P<0.01),DSU与DCHN、DUS和DINT相关性较差,线性回归方程可实现DCHN、DUS和DINT之间的转化.综合考虑土壤颗粒组成信息、数值差异和相关性,美国制土壤粒径分级方法是计算土壤体积分形维数的较优选择.

We constructed an aeolian soil database in the Mu Us Desert. Soil particle size distribution（ PSD） was measured with a laser diffraction technique,and the volume-based fractal dimensions were calculated following the standards of Chinese（ DCHN）,Soviet（ DSU）,American（ DUS）,and International（ DINT） soil PSC systems. The results indicated that（ 1） The predominant soil particle size was distributed within the sand classification,which accounted for more than 90%of the total volume; Clay and silt particle contents were much less prevalent. The order of volume-based fractal dimensions was as follow： DSU,DCHN,DINT,and DUS.（ 2） Significant linear correlations occurred among DCHN,DUS,DINT,and clay,silt and sand particle contents（ P〈0. 01）,respectively,with the exception of any significant correlations between DSUand silt and sand particle contents（ P〈0. 05）,which showed a poor linear relationship.（ 3） There were significant positive correlation among DCHN,DINTand DUS（ P〈0. 01）,where there were poor correlations between DSUand other fractal dimensions. The linear regression analysis realized mutual transformation among DCHN,DUSand DINT. Taking into consideration soil PSD data,D values,and the observed correlations,we highly recommend that the American soil PSC system should be the optional system for calculating volume-based fractal dimensions of soil PSD.