中文摘要：

坡面薄层水流侵蚀不仅造成土壤养分流失,土壤质量恶化,同时对水体污染等环境问题造成一定影响。为了分析上方来水流量对红壤坡面径流侵蚀过程中泥沙的迁移规律及土壤溶质运移特征的影响,本试验利用室内放水冲刷试验,采用3个不同上方来水流量（10 L min-1、15 L min-1、20 L min-1）对第四纪黏土发育红壤坡面径流侵蚀过程中坡面径流泥沙和径流中非吸附性离子（Br-）迁移过程进行了研究。结果表明：不同上方来水条件下,放水初期产流量迅速增大,后期趋于稳定,累积径流量与产流时间成显著的线性关系,10 L min-1、15 L min-1、20 L min-1三种上方来水流量下累积径流量分别为263.2 L、295.1 L、291.04 L;上方来水流量越大,薄层径流冲刷作用越强烈,径流含沙量随时间变化波动越剧烈,累积泥沙量随产流时间呈幂函数变化,15 L min-1、20 L min-1流量下累积泥沙量分别为10 L min-1流量下累积泥沙量的1.42倍、4.25倍;径流Br-浓度随产流时间呈幂函数衰减,反映了土壤溶质随径流迁移量变化主要受水流与土壤接触时间和作用程度的影响。研究表明放水冲刷对土壤侵蚀及溶质运移有重要作用,试验结果对有效预测与控制红壤坡面侵蚀及养分流失具有重要实际意义。

英文摘要：

The subtropical red soil hilly region in South China,rich in hydrothermal and soil resource,is one of the most important grain production regions,playing a key role in development of the agricultural economy of the country. With the economy developing so fast,human activities in the region are getting too intensified,leading to destruction of large tracts of natural vegetation and consequently,declining soil and water conservation capacity. Abundant rainfall in the region causes large volumes of surface runoff eroding the thin soil layers on the slopes,which not only results in soil nutrient loss and soil quality degradation,but also brings about serious environmental problems in the lower reaches of the river valleys. Therefore,it is imperative to develop researches of mechanisms of the soil erosion and nutrient translocation for conservation of the red soil resources.In order to understand influences of shallow clear-water flow scouring on soil erosion and solute transport,a laboratory scouring experiment,designed to have three scouring inflow rates（10 L min-1,15 L min-1 and 20 L min-1）,was conducted on artificial slopes of red soil derived from quaternary red clay and effects on the transport processes of non-sorbed chemicals（bromine）in runoff and sediment during the processes of soil erosion caused by surface runoff were evaluated. Results show that flow velocity of the runoff on the slope surface increased with increasing volume of the incoming flow from the upper slope;no matter how the flow conditions were in the upper slope,runoff yielding rate increased rapidly at the initial water releasing stage and then tended to level off;an apparent linear relationship was observed between cumulative runoff volume and duration of runoff yielding;when water flew down at a rate of 10 L min-1,15 L min-1 and 20 L min-1 from the upper slope,the cumulative runoff volume reached 263.2 L,295.1 L and 291.04 L,respectively;the higher the volume of the flow from the upper part,the stronger the scouring effect of the sh