三峡库区紫色砂岩不同发育程度土壤入渗特征及其影响因素

Soil Infiltration Characteristics and Influencing Factors of Purple Sandstone with Different Degrees of Development in the Three Gorges Reservoir Area

为探究典型母岩不同发育程度土壤入渗特征,在三峡库区王家桥小流域采用圆盘入渗仪测定新成土(S1)、雏形土(S2)、淋溶土(S3)3种紫色砂岩不同发育程度土壤入渗过程,探究入渗过程的影响因素,并用3种常用模型进行入渗过程模拟,分析比较这些模型的适宜性。结果表明:(1)不同发育程度间土壤理化性质差异显著。雏形土和淋溶土土壤容重较新成土分别增加10.71%,19.50%,土壤总孔隙度分别降低8.79%,18.69%,通气孔隙度分别降低67.40%,8.16%,土壤黏粒含量分别增加10.01%,38.36%,砂粒含量分别减小8.09%,48.29%,土壤有机质分别增加2.88%,8.68%。(2)不同发育程度土壤间初始入渗率、平均入渗率、饱和导水率均表现为新成土>雏形土>淋溶土,雏形土、淋溶土平均入渗率及饱和导水率分别是新成土的0.99,0.58和0.89,0.83倍。(3)不同发育程度土壤理化性质差异对土壤入渗具有显著影响,土壤入渗速率与总孔隙度、毛管孔隙度、通气孔隙度、砂粒含量呈正相关关系,与容重、黏粒含量、有机质含量呈负相关关系。(4)Horton模型对紫色砂岩不同发育程度土壤入渗过程拟合效果最优(R^(2)=0.942),Kostiakov模型次之(R^(2)=0.858),Philip模型拟合效果较差(R^(2)=0.832)。通过观测与模拟不同发育程度土壤入渗过程,研究结果可为流域土壤水分运移规律探究提供有益借鉴。

In order to explore the soil water infiltration characteristics of typical parent rocks with different developmental degrees,a disc infiltration meter was used to determine the infiltration process of three kinds of purple sandstone with different development degrees,which were Entisol(S1),Cambisols(S2)and Alfisol(S3),to explore the influencing factors of the infiltration process,and three common models were used to simulate the infiltration process to analyze and compare the suitability of these models.The results showed that:(1)There were significant differences in soil physicochemical properties among different development degrees.Compared with the Entisol,the soil bulk density of the Cambisols and Alfisol increased by 10.71%and 19.50%,the total soil porosity decreased by 8.79%and 18.69%,the aeration porosity decreased by 67.40%and 8.16%,and the soil clay content increased by 10.01%and 38.36%,the sand content decreased by 8.09%and 48.29%,and the soil organic matter increased by 2.88%and 8.68%,respectively.(2)The initial infiltration rate,average infiltration rate and saturated hydraulic conductivity of soils followed the order of Entisol>Cambisols>Alfisol,and the average infiltration rate and saturated hydraulic conductivity of Cambisols and Alfisol were 0.99,0.58 and 0.89,0.83 times higher than those of the Entisol,respectively.(3)Differences in soil physical and chemical properties of different soil development levels had a significant impact on soil water infiltration.Soil infiltration rate was positively correlated with total porosity,capillary porosity,aeration porosity and sand content,while negatively correlated with bulk density,clay content and organic matter.(4)The Horton model had a better fitting effect on the purple sandstone soil water infiltration process with different development degrees(R^(2)=0.942),followed by the Kostiakov model(R^(2)=0.858),and the Philip model had a poor fitting effect(R^(2)=0.832).By observing and simulating the process of soil water infiltration of different development levels,the research results could provide a useful reference for the study of the soil water migration law in the watershed.