层状土壤中砂层层位对潜水蒸发的影响  

Effect of the sand layer position on the phreatic evaporation in the layered soil profile

作　　者：史文娟[1] 沈冰[1] 汪志荣[1] 王文焰[1] 

机构地区：[1]西安理工大学水资源与环境陕西省重点实验室,陕西西安710048

出　　处：《干旱区地理》2006年第2期282-286,共5页Arid Land Geography

基　　金：国家自然科学基金(59879022;40271022);陕西省教育厅专项科研基金(04JK229-1);西安理工大学高学历人员科研启动基金资助

摘　　要：通过室内一维土柱实验,研究了夹砂层土体构型中砂层层位对潜水蒸发的影响,分析了其影响机理,进一步讨论了砂层位置和水分蒸发的定量关系。结果表明,砂层对于水分的蒸发既有促进也有抑制作用,在地下水埋深为50cm时,5cm厚的底砂层可使水分的蒸发强度增加10％-20％；砂层距水位的距离大于5cm时,砂层可抑制水分的蒸发,且当距离增加到35cm左右,其抑制率可达70％-80％；当砂层距水位的距离继续增大时,水分的蒸发强度基本保持不变。这主要是由砂层自身的导水率变化以及砂层与同剖面中其它土质导水率的相对大小发生变化而引起。累积蒸发量与砂层层位以及蒸发历时之间定量关系的建立为预测砂层对潜水蒸发的影响以及估算特定历时蒸发损失量最小的砂层层位提供了依据。The effect of the sand layer position in layered soil profile on the phreatic evaporation rate was researched through the laboratory simulating soil columns indoor. The mechanism was analyzed and the quantitative relationship between the evaporation rate and the sand layer position was discussed. The results showed that the sandy soil in layered soil profile can stimulate or obstacle the water movement as compared to the uniform loam column with 50cm depth of water table, this was mainly determined by the position of the sand layer. When the distance between the low boundary of and layer with 5cm thickness and the water table is zero, the evaporation rate increased with 10- 20% ratio. When the distance is more than 5cm the rate started to decrease, and the rate decreased with 70-80 % ratio for the sand layer soil column with 35cm distance. The rate keep relative steady when the distance was more than 35cm. This changes outlined above were determined by the hydraulic conductivity of the sand layer and the relative size of hydraulic conductivity of these soils in layered soil profile. Finally, the functional relationship between the accumulative evaporation and sand layer position and evaporation duration was developed. The equations are important for forecasting the effect of sand layer on evaporation rate and calculating the proper sand layer position, which made the evaporation loss is least.

关 键 词：夹砂层土壤 砂层层位 潜水蒸发 

分 类 号：S152.7[农业科学—土壤学] TU473.13[农业科学—农业基础科学]