田间尺度下土壤水流非均匀运动特征的染色示踪研究

Study on heterogeneous characteristics of soil water flow in field by dye tracing method

根据碘和淀粉的显色反应原理对土壤优先流进行了示踪研究,开展了入渗水量深度分别为20mm、40mm、60mm和80mm的4组染色示踪试验。通过对垂直剖面流动模式的分析和对整个试验区域入渗深度分布的统计分析,研究了土壤水流运动的非均匀特征与入渗初始条件和边界条件之间的关系。研究结果表明:(1)土壤水流运动在剖面内和剖面之间均表现出明显的变异特征;(2)土壤初始含水率升高对土壤优先流的发展有明显的抑制作用、降低了入渗在剖面内和剖面间的变异程度;(3)随着入渗水量的增大,土壤水入渗的非均匀程度非线性减小,但过多的增大入渗水量对提高入渗均匀度的作用有限;(4)互相关函数分析可成功地用来研究土壤水流入渗变异特征的方向性、比较入渗在剖面内和剖面间变异程度的大小以及确定入渗区域中土壤优先流的可能最大宽度。

The iodine-starch staining method was used to visualize the preferential heterogeneous flow in soils.Four sets of tracing experiment with hydraulic head of 20mm,40mm,60mm and 80mm were carried out.The heterogeneous infiltration characteristics related to the initial soil water content and boundary conditions were analyzed using statistical method based on the experimental data.The results show that: 1.infiltration distributions within and among the soil profiles exhibit distinct heterogeneities;2.the higher...