野外非饱和土壤中溶质运移的试验研究

Field Experiment on Solute Transport in an Unsatnrated Soil

通过在野外3×6m^2面积上均匀入渗条件下非饱和土壤溶质运移试验,同时对8个点定时取样,得到170cm深度内土壤溶液浓度和含水量剖面分布。据此研究了小区域范围内土壤水分和溶质的运移特征,讨论了土壤水分和盐分分布的空间变异性和统计特征.研究结果表明,在本试验条件下,土壤溶液浓度剖面的空间变异性远大于土壤水分剖面。单一测点的取样结果不能代表区域的溶质运移特征.区域上溶质浓度的平均结果能反映溶质运移的基本规律。由于土壤结构等因素的影响,不动水体含量占土壤含水量的24％～39％。

Solute concentration and water content profile at the depth to 170cm in an area of 3×6 cm2 during constant leaching to an unsaturated soil were measured at eight points for the determined times. Soil water movement and solute transport in the local scale were studied and the spacial variability of soil water content and concentration were discussed. As compared with the water content profile, the concentration profile shows a very great variation. The concentration profile measured at one point can not be used to represent the local scale concentration behavior. The immobile water content is about 24 to 39 percent of total water content in the experiment.