大孔隙分布对坡地产汇流及溶质运移的影响

以室内土槽为平台,采用人工模拟降雨试验,研究了粉砂壤土中两种不同大孔隙分布情况下,土槽中土壤含水量、坡面流速、地面径流、地下径流及溶质运移的变化。结果表明,相对于面大孔隙度为19%,容积大孔隙度为0.095%的未加密型的土槽,面大孔隙度为57%,容积大孔隙度为0.285%的大孔隙加密型土槽中各层土壤含水量增加幅度、平均坡面流速及地面径流量相对偏小,地下流出现时间较早且径流量较大,地面径流中溴离子、铵根离子浓度、硝酸根离子浓度偏小。在地下水出流前期,大孔隙加密型土槽中的铵根离子浓度和浓度变化幅度都偏小,但溴离子、硝酸根离子浓度则偏大。

Effects of Soil Macropores Distribution on Slope Runoff Yield and Solute Transport

In order to find the effect of soil macropore distribution on overland flow and solute transport, artificial rainfall experients were carried out. The results showed that compared to original macropore soil tank, in the increased density macropore soil tank with the surface porosity of 57% and the volume porosity of 0.285%, the increasing extents of the soil water content of every layer were less, the velocity of overland flow was smaller and the runoff amount of surface was less, the runoff amount of underflow appears earlier and was more in increasing-density macropore soil tank. The results also indicated that in increased density macropore soil tank, the concentration of Br^-, NH₄⁺ and NO₃^- in surface runoff were lower, the concentrations of Br^- and NO₃^- in the underflow runoff were higher in earlier stage of the groundwater outflow, but the concentration of NH₄⁺ was lower and the increasing extend was smaller.