摘要
设计了自由排水、土壤水分饱和和壤中流3种水文条件,采用人工模拟5组不同地表径流流速,分别对土壤溶质迁移到地表径流过程中土壤侵蚀、伯努利效应、扩散和对流4种途径的作用机理进行了分析。结果表明,在土壤水分饱和条件下,伯努利效应引起的土壤溶质流失量占总流失量的比例很大。结合混合层理论和试验得到了3种水文条件下混合层的深度,其中自由排水(-10 cm)时混合层深度小于1.5 mm;在土壤水分饱和条件下,混合层深度介于0.9~4.5 mm;但是在壤中流条件下,混合层表现为整个土层都为混合层深度。
Although there is a conceptual understanding on processes governing chemical transport from soil to surface runoff, there are little literature and research results actually quantifying these individual processes. We developed a laboratory flow cell and experimental procedures to quantify chemical transport from soil to runoff water by each of the individual processes, i. e. , (1) erosion; (2) convention; (3) Bernoulli effect; and 4) diffusion. We imposed 3 different vertical hydraulic gradients by setting 5--flow cell to free drainage condition (-10 cm), saturation condition and artesian seepage condition (10 cm). Our data confirmed the general form of the convection-diffusion equation; nevertheless, we now have additional quantitative data describing the contribution from each individual chemical loading process under different surface runoff and soil hydrologic conditions. The results idehtified that Bernoulli Effect made a great contribution to transport ehemical from soil into surface runoff under saturation condition. According to our data, the mixing zone depth is gotten by mixing theories under different hydraulic gradients.
出处
《水土保持学报》
CSCD
北大核心
2009年第3期1-5,共5页
Journal of Soil and Water Conservation
基金
美国农业部项目“土壤水动力及其在土壤侵蚀和水质的有效管理”(3602-12220-009-00)
关键词
自由排水
壤中流
土壤水分饱和
土壤溶质
地表径流
伯努利效应
soil
free drainage condition
artesian seepage condition
saturation condition
chemical transport
runoff
Bernoulli effect