【摘要】 非饱和土壤的水力性质是进行土壤中水分与污染物运移模拟的物理参数,其中土壤水分扩散率是定量模拟土壤水分流动和溶质运移的最重要的参数之一。通过对甘肃省南小河沟流域不同地貌、不同土地利用方式的土壤分层取样,采用水平土柱吸渗法测定各地类的非饱和土壤水分扩散率;运用土壤水分扩散率的单对数模型和双对数模型对试验结果进行分析。结果表明:单对数模型参数具有明显的线性相关,可以建立表征描述南小河沟各地类的土壤水分扩散率的单一参数的单对数模型;进一步从全流域及划分地类后得到的模型参数B与A的关系分析表明它们具有较好的线性关系,可对模型进一步简化为单一参数模型。分析单一参数模型B的统计特征表明:参数B随着地貌类型的变化具有一定的变化特征,可作为土壤水分扩散率空间变异的变异系数。因此,可以用参数B作为反映地貌类型的指标,应用于区域土壤水分扩散率的估计中。更多还原

【Abstract】 Selection and identification of soil hydraulic properties parameters are the base of soil water movement and prediction of pollutants transport.Unsaturated soil hydraulic properties are important physical parameters for modeling waterflow and solutes transport,in which soil water diffusivity is one of the most important parameters. However,because these parameters have a strong spatial variability,making a direct determination of them in a larger region is often not feasible,and by the spatial structure of soil variability in the determination of the existence of large errors.To overcome these shortcomings,soil structure and hydraulic parameters of the function must be established in order to find a determination of soil moisture characteristics of the more simple and effective method.In this paper,the infiltrating method by horizontal soil column was applied to characterize soil water diffusivity with the different landform condition and different land - use types in the loess hilly areas in the Nanxiaohegou basin of Gansu province.And the experimental results sampled from 18 land use types were analyzed by single -logarithm model and double - logarithm model of soil water diffusivity.The result showed that parameters of single - logarithm model have significant linear correlativity,so single - logarithm model with a parameter could be established to describe soil water diffusivity of the different landform condition and different land - use types in the Nanxiaohegou basin. On the basis of further analyzing relationship between parameter A and B of single - logarithm model,it showed that all of them in the different landform types and whole basin were the linear relationship.So,it can be established the single logarithmic model to characterize the soil water diffusivity of the Nanxiaohegou basin.With the help of analyzing the statistical characteristic of parameter B,it was found that parameter B had certain change characteristic along with the landform type change,which may be taken as thevariation coefficient of soil moisture diffusivity spatial variation.Therefore,B can be used as the indicator to apply in valuation of regional soil water diffusion更多还原