运用染色示踪方法研究土壤质地对土壤水非均匀流动特征的影响

为研究土壤质地对土壤水流运动非均匀特征的影响,在砂土、壤土和粉质粘土中采用亮蓝(砂土)和碘离子(壤土和粉质粘土)作为示踪剂分别开展了2个、5个和4个不同入渗条件(土壤初始含水率和入渗水量)的染色示踪试验,通过计算活动流场模型(Active Region Model,ARM)分形特征参数(γ)来定量描述和比较不同入渗条件下土壤水流运动的非均匀特征。研究结果表明,(1)活动流场模型较好的捕捉到了土壤水流运动整体的非均匀信息;(2)当其它入渗条件(土壤初始含水率和入渗水量)相同时,土壤水在细质地土壤中运动的非均匀程度要高于其在粗质地土壤中运动的非均匀程度。

The Impacts of Soil Texture on Water Flow Heterogeneity with Dye Staining Methods

To study the impacts of soil texture on heterogeneous soil water flow,a total of 11 dye staining experiments using Brilliant Blue and Iodine ion as the dye tracer were conducted in Sand(Brilliant Blue,2 plots in total),Loam(Iodine ion,5 plots in total) and Silty Clay(Iodine ion,4 plots in total).Dye coverage and soil water content within the dye stained region were measured to determine the Active Region Model(ARM) parameter(γ) which was used to characterize and compare the flow heterogeneity resulted from different flow conditions.This research indicated that:(1) the ARM captured the major behavior of preferential flow very well,and(2) the soil water flow occurred more heterogeneously in the fine-textured soil than that in coarse-textured soil if under the same initial soil water content and infiltration amount conditions.