盐水入渗和有植物条件下室内层状土壤水盐运移的研究

Study on Saltwater Infiltration and Water and Salt Transport in Indoor Stratified Soil Under Vegetative Conditions

自然界中的土壤大多呈层状结构,对水盐运移以及植被生长具有重要影响。为研究其影响,同时为了解植物水分的有效利用情况,进行了植物生长条件下的室内强异质层状土柱(上层为壤土,下层为河砂)水盐运移试验以及区分植物蒸腾、棵间蒸发的试验。研究结果表明:在植物生长条件下的室内强异质层状土柱水盐运移试验的入渗中,当盐水入渗到两层变化边界时会出现短暂的停滞,下层河砂有一定的减渗作用,但由于指流的存在,体积含水率的变化波动较大。盐分随水分的运动而运移,下层河砂中盐分运移受水流影响,对流占主导作用。蒸发过程中,层状土柱粗砂层有阻止水分运动的作用。在区分植物蒸腾、棵间蒸发的试验中,当蒸散发总量达到一定值时,蒸发会被抑制。研究结果为土壤盐渍化防治及盐渍土改良提供了数据支持。

In nature, soil is mostly layered, which has an important influence on water and salt transport and vegetation growth. In order to study its effect and to understand the effective utilization of water by plants, the experiment of water and salt transport and the experiment of plant transpiration and evaporation were carried out under the condition of plant growth in laboratory with strong heterogeneous layered soil column(upper layer is loam and lower layer is river sand). The results show that in the water and salt transport experiment of strong heterogeneous layered soil column under plant growth condition in laboratory, when brine infiltration penetrates to the variation boundary of two layers, there will be a temporary stagnation, and the lower river sand has a certain permeability reduction effect, but because of the existence of finger flow, the change of volume water content fluctuates greatly. Salt migrates with the movement of water, and salt migration in the lower river sands is influenced by water flow and convection plays a dominant role. The coarse sand layer of layered soil column can prevent water movement in evaporation process. In the experiment of distinguishing plant transpiration and inter-plant evaporation,evapotranspiration will be inhibited when the total evapotranspiration reaches a certain value. This study provides data support for soil salinization prevention and salinization improvement.