An experimental study on behaviors of water and chemicals in a non-uniform soil layer and its mechanism under evaporation

在arid和半arid地区，蒸发和salinization成为一种非常重要的现象，必须被明确。在本研究中，Akamai-土壤层与双杆结构（宏观杆和微型杆）聚焦于非均匀土壤，并利用层进行蒸发实验，利用土壤在温度和湿度控制的房间中利用分散的水和丰富的氯化钠溶液进行了利用。对太阳辐射、水桌和湍流表面风的测试影响，在某些情况下，这样的条件已应用于层。通过蒸发实验，接下来的是明确的。1.微柱发挥了一个基于土壤水的传输路径的作用，并导致了更高的蒸发率。2.应用的表面风的涡轮到暴露的表面渗透通过宏观柱更容易地进入土壤，并在土壤层有意义的蒸发转移中影响蒸汽。因此，在土壤层中的蒸汽转移，不仅仅是分子扩散，但也有一个扭曲的表面风必须被接受帐户3.上层表面的加热导致了一个特征性的蒸汽密度剖面在土壤的峰值所在的蒸发区。蒸发产生的蒸汽是在上游和下游方向传输的。在一个较深的位置向下移动的蒸汽条件，因此土壤水通过蒸发、蒸汽转移和冷凝过程被带入一个较深的区域。4.在土壤层的上层区域中增加土壤水的出现，在那里，钠+的浓度和氯开始以明显的减少深度。这个位置有更多或更少的一致性与干燥前端的上端。在深度以下的集中，作为一个结果，成为比初始的碎片更低的东西·这可能会导致吸收和离子交换在土壤颗粒上。

In arid and semi-arid areas, evaporation and salinization becomes quite important phenomena which must be to clarified. In this study, Akadama-soil layers with a dual pore structure (macro-pores and micro-pores) were focused on as a non-uniform soil, and evaporation experiments using the layers moistened by distilled water and enriched NaCl solution were undertaken in a temperature and humidity controlled room at 25℃ and 20%. To examine effects of a solar radiation, water-table and turbulent surface wind to evaporation, in some cases, such conditions were applied to the layer. Through the evaporation experiments, the following are clarified.1.Micro-pores play a role of transmission route of underlying soil-water to an evaporation zone, and it causes evaporation rate higher.2.Turbulence of applied surface wind to the exposed surface penetrates easily into soil through macro-pores, and it affects vapor transfer in the soil layer significantly. Therefore, in the vapor transfer in the soil layer, not only molecular diffusion but also turbulent one caused by the surface wind must be taken account3.The heating on the upper surface leads a characteristic vapor density profile in the soil with a peak at which the evaporation zone is located. Water vapor created by evaporation is transported in the upper and lower directions. The downward moving vapor condenses in a deep location, therefore soil-water is carried to a deep zone via evaporation, vapor transfer and condensation process.4.Enrichment of soil-water appears in an upper zone of the soil layer, where the concentrations of Na+ and Cl start to increase abruptly with decreasing depth. This location is more or less consistent with the upper end of drying front. The concentrations below that depth, as a result, become lower than initial ones・this may be due to absorption and ion exchange on the soil-particles.