基于含水量高频监测的花岗岩崩岗侵蚀红壤优先流研究

发布时间：2019-04-07 15:55

【摘要】：为了研究崩岗侵蚀土壤的水分运动特征,采集湖北通城县花岗岩崩岗区的红壤,研究优先流及影响因子。把采集的1种红土和3种砂土按照野外"上红下砂"层次顺序,分别装填到长60cm,宽11cm,高110cm的透明PVC土箱。3个土箱在不同初始含水量(12.2%~23.6%)和雨强(0.7,1.2mm/min)下进行模拟降雨入渗,用时域反射仪(TDR)高频监测土体20个部位含水量瞬时动态,根据含水量的时空变化识别土体优先流发生特征。结果表明,降水入渗多表现为非均匀入渗,土壤饱和导水率较大、大孔隙路径状况较好的土体更容易发生优先流,其影响范围更广。雨强越大,优先流与周围基质作用越明显,优先流反应量越大,雨强1.2mm/min的优先流速率是0.7mm/min的1.8~4.0倍。且小雨强的优先流程度受土箱初始含水量影响大于大雨强处理,在雨强1.2mm/min时,优先流程度随初始含水量的增加而减小;当雨强减小为0.7mm/min时,优先流程度随初始含水量的增加先增大后减小。优先流发生受降水特性和初始含水量影响,但土壤性质对优先流的影响更大。
[Abstract]:In order to study the water movement characteristics of the eroded soil in Tongcheng County, Hubei Province, the red soil was collected and the priority flow and its influencing factors were studied. One kind of red soil and three kinds of sand collected were packed to 60 cm in length and 11 cm in width according to the order of "upper red and lower sand" in the field. A transparent PVC soil box with high 110cm was used to simulate rainfall infiltration under different initial water content (12.2% ~ 23.6%) and rainfall intensity (0.7, 1.2 mm / min). The time domain reflectometer (TDR) was used to monitor the instantaneous dynamics of soil moisture content in 20 parts of the soil at high frequency. The results show that the precipitation infiltration is mostly non-uniform infiltration, the saturated hydraulic conductivity of soil is larger, and the soil with better macro-pore path is more prone to preferential flow, and its influence range is wider. The greater the rain intensity, the more obvious the interaction between the preferential flow and the surrounding matrix, and the greater the reaction amount of the preferential flow is. The preferential flow rate of the rain intensity 1.2mm/min is 1.8 times as much as that of the 0.7mm/min. The preferential flow degree of light rain intensity is more affected by the initial water content of the soil box than that of the heavy rain treatment. When the rain intensity 1.2mm/min, the priority flow degree decreases with the increase of the initial water content. When the rain intensity decreases to 0.7mm/min, the priority flow degree increases first and then decreases with the increase of initial water content. The preferential flow is affected by the precipitation characteristics and initial water content, but the soil properties have more influence on the priority flow.
【作者单位】：华中农业大学资源与环境学院;
【基金】：国家自然科学基金“花岗岩红壤优先流及其与崩岗侵蚀发育的关系”(41571258)
【分类号】：S157

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