紫色土坡耕地裂隙潜流的产流机理与胶体颗粒迁移

发布时间：2018-04-18 20:39

本文选题：裂隙潜流 + 产流　；参考：《环境科学研究》2017年12期

【摘要】：土壤胶体是坡耕地农化物质迁移的主要载体.借助18O(氧同位素)示踪技术,探索了2014年8月29日和9月10日两场降雨下大型紫色土坡耕地(1 500 m~2)裂隙潜流产流的水源来源及过程特征,并耦合了胶体颗粒释放与迁移机理的研究.结果表明,裂隙潜流及胶体迁移的水文过程线均总体呈快速上升和长拖尾的特征.随裂隙潜流产流开始,雨水对潜流的贡献逐渐增大,并在流量快速上升段支配裂隙潜流产流,而潜流流量峰值前及退水阶段,土壤前期可动水是潜流的主要产流来源.两场降雨下裂隙潜流中胶体颗粒浓度介于0.60~6.85 mg/L之间,平均值分别为1.58和2.31 mg/L,水浴超声后胶体颗粒浓度平均值分别为原样的2.15和1.81倍.胶体颗粒迁移速率比产流速率快(30 min),表明胶体辅助坡地农化物质迁移的潜力较大.对于长历时小降雨事件,潜流中胶体的迁移动态受潜流水化学因素[如ρ(DOC)、ρ(Mg2+)和EC(电导率)]支配,而强降雨事件下,潜流中胶体颗粒浓度还与潜流流量呈极显著负相关(R~20.5).此外,坡地内部产流方式(横向及垂向)对裂隙潜流中胶体颗粒的迁移通量有重要影响.研究显示,裂隙潜流产流过程线结合土水势、18O及水化学指标的动态变化,能够全面揭示裂隙潜流产流的阶段特征以及胶体颗粒释放与迁移的机理,对于进一步研究胶体对磷、有机农药等憎水性农化物的辅助运移特征有重要意义.
[Abstract]:Soil colloid is the main carrier of agrochemical material migration in sloping farmland.With the help of the 18O (oxygen isotope) tracer technique, the source and process characteristics of water source and process of subsurface flow in sloping land of large purple soil with rainfall of August 29 and September 10, 2014 (1 500 m / 2) have been explored.The mechanism of release and migration of colloidal particles was also studied.The results show that the hydrological process lines of fracture subsurface flow and colloid migration generally show the characteristics of fast rising and long trailing.Rain Water's contribution to the subsurface flow increases gradually with the initiation of the fissure subsurface flow, and dominates the fissure subsurface flow in the rapid rising section of the flow rate. Before the peak of the subsurface flow flow and in the receding stage, the main source of the subsurface flow is the moveable water in the early stage of the subsurface flow.The concentration of colloid particles in the fracture undercurrent is between 0.60 and 6.85 mg/L with the mean values of 1.58 and 2.31 mg / L, respectively, and the average concentration of colloidal particles after water bath ultrasound is 2.15 and 1.81 times of that of the original sample, respectively.The migration rate of colloidal particles was 30 minutes faster than that of runoff production, which indicated that colloid assisted agrochemical material migration on sloping land had great potential.For long duration and small rainfall events, the transport dynamics of colloids in the subsurface flow are controlled by the chemical factors of submersible flow (such as 蟻 -DOC, 蟻 -Mg2) and EC (electrical conductivity). However, under heavy rainfall events, the concentration of colloid particles in the subsurface flow is also negatively correlated with the flow rate of the subsurface flow.In addition, the flux of colloidal particles in the subsurface flow of fractures is greatly affected by the runoff generation mode (transverse and vertical) in sloping land.The results show that the process line of fissure subsurface flow, combined with the dynamic change of soil water potential (18O) and hydrochemical index, can fully reveal the stage characteristics of fissure subsurface flow and the mechanism of colloidal particle release and migration. For further study of colloidal phosphorus,The auxiliary transport characteristics of hydrophobic agrochemicals such as organic pesticides are of great significance.
【作者单位】：重庆工商大学旅游与国土资源学院;中国科学院水利部成都山地灾害与环境研究所山地表生过程与生态调控重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(41601539,41471268)
【分类号】：S152;S153.3

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