基于环境同位素的红壤坡地水分运移研究

应用土壤学、水文学研究手段,结合环境同位素示踪技术,从形态学、能量学两个角度,分析了红壤坡地油茶生态系统土壤水分的运移规律以及壤中流的发生机制。结果表明,降雨入渗过程初期0—40cm土层土壤水分受降雨入渗及蒸散发影响最大;40—90cm为过渡层次,水分呈上下交替运移。与浅根系荒草地相比,深根系的油茶林更利于壤中流的发生,同一土壤层次油茶林壤中流产流量较大,但峰值流量较低,产流过程开始早,结束晚;浅根系植被的荒草地降雨多以地表径流形式流失,难以入渗蓄水;同一植被状况,产流量、峰值流量、滞后和拖尾均为上层(0—40cm)小于下层(40—110cm)。稳定性氢氧同位素测定结果表明,壤中流的发生条件之一是存在相对的饱和层,且产流主要来自驱替而出的原有土壤水分。

A Study of Water Transportation on Red Soil Slope Based on Environmental Isotope Technologies

The dynamic processes of soil water movement and interflow occurrence mechanisms for Camellia oleifera ecosystem on red soil sloping land were analyzed based on environmental isotope technologies,soil science and hydrological experiments in terms of morphology and energetics.Results showed that in the initial stage of rainfall infiltration,soil water in the upper layer(0—40 cm) was affected obviously by rainfall infiltration and evapotranspiration.The 40—90 cm layer was a transitional layer and soil water moved alternately upwards and downwards in rainfall infiltration process.Compared with wild grass ground,Camellia oleifera ecosystem with deep roots was easier for the occurrence of interflow.In the same soil layer,the amount of interflow in Camellia oleifera ecosystem was higher,whereas the peak value of interflow was lower and the progress of interflow occurrence lasted longer.Rainfall on the surface of wild grass ground with shallow roots was mostly lost as surface runoff,so it was difficult for infiltration and storage to occur.With the same vegetation coverage,interflow production,peak,lag and trailing in the upper layer(0—40 cm) were less than those in the lower layer(40—110 cm).The dynamic change of stable hydrogen and isotope of soil water indicated that a relatively saturated layer was one of basic conditions for the occurrence of interflow and the interflow was mainly from the displaced initial soil water.