土壤入渗特性的空间变异性及土壤转换函数

Spatial variability of soil infiltration characteristics and its pedo-transfer functions

以在杨陵一级阶地上进行的入渗试验为基础,利用多重分形和联合多重分形方法,研究分析了土壤入渗特性在多尺度上的空间变异性及与土壤物理特性的相关性,并在此基础上建立了土壤入渗特性的土壤转换函数。研究表明:土壤入渗特性具有多重分形特征,观测尺度上,稳定入渗率、前30 min累积入渗量的空间变异都主要由粗粉粒和粘粒含量的空间变异造成。在多尺度上,稳定入渗率的空间变异受土壤容重、粗粉粒和粘粒含量的空间分布影响显著,前30 min累积入渗量的空间变异受粗粉粒和粘粒含量的空间分布影响显著,与观测尺度上的影响因素相同。基于联合多重分形分析建立的稳定入渗率的土壤转换函数的计算误差较小,前30 min累积入渗量的土壤转换函数的计算误差较大。

Based on the experimental data collected from the first terrace in Yangling station,we perform both multifractal analysis and joint multifractal analysis to investigate the spatial variability and relationship between the stable infiltration rate and soil infiltration characteristics,and establish the pedo-transfer functions（PTFs） of soil infiltration characteristics.The results show that the infiltration characteristics are multifractal.The observed spatial variability of stable infiltration rate and the beginning 30-min cumulative infiltration are mainly caused by the different sand and clay contents in the soil samples.The multi-scale analysis results show that the spatial variations of soil sand content and organic matter content have significant influences on the spatial variability of steady infiltration rates.The beginning 30-min cumulative infiltration is mainly affected by the distributions of slit and clay content which are the same factors in multi-scale as the observation scale.Two pedo-transfer functions of infiltration characteristics are established with the joint multifractal analysis and the beginning 30-min cumulative infiltration,respectively.The computational error of the former is less,the later is relatively larger.