元谋干热河谷冲沟集水区土壤入渗性能及其影响因素

Soil Infiltration and Its Influencing Factors in Gully Drainage Areas in Yuanmou Dry-hot Valley Region

试验研究元谋干热河谷冲沟沟头集水区5种土地覆被类型的土壤入渗特征及其影响因素。结果表明:(1)冲沟沟头集水区不同覆被类型下土壤入渗性能存在较大差异。裸地A(地表无铁锰胶膜)和裸地B(地表有铁锰胶膜)的入渗性能远远低于印楝林地、耕地和草地的入渗性能,这可能是导致裸地A、裸地B所在沟头发育仍然活跃的原因之一;(2)3种公式拟合效果以通用经验公式为最佳,拟合结果表明,初始入渗速率和稳定入渗速率均按照印楝林地>耕地>草地>裸地A>裸地B的顺序递减;(3)相关分析表明,土壤砂粘比、总孔隙度、毛管孔隙度、容重均与各土壤入渗性能指标呈显著的相关关系,但非毛管孔隙度、有机质含量、初始水分含量与入渗性能指标相关性不显著。主成分分析也表明,土壤容重、毛管孔隙度和砂粘比是影响该区土壤入渗性能最重要的3个因子。

Soil infiltration characteristic and its influencing factors were studied under ttve land-cover types m gully drainage areas in Yuanmou dry-hot valley region in this paper. Results indicated that. （1）Differences on soil infiltration capacity among the five land-cover types were significant, especially for the bare land A and bare land B, whose infiltration capacities were much more lower than those of the other three types, which probably is one of the reasons that the corresponding gully heads were still active. （2）The fitting effect of u- niversal empirical equation was the best among the three equations used in the paper. And the fitting result also showed that the ranking sequences of the initial infiltration rate and the stable infiltration rate were the same as woodland〉cultivated land〉grassland〉bare land A〉 bare land B. （3） Correlation analysis showed that, the ratio between sand and clay, the total porosity, the capillary porosity and the bulk density were all found to have a significantly positive relationship with all of the three infiltration indexes. However, there existed no significant correlation for the non-capillary porosity, the content of organic matter and the initial soil water content with the three infiltration indexes. The principal component analysis also indicated that the soil bulk density, the capillary porosity and the ratio between sand and clay were the three major factors which greatly influenced soil infiltration characteristics in the study region.