胶体吸附污染物并辅助其在降雨-径流过程中快速由土壤迁移至水体是当前面源污染防治面临的新问题。贵州省西南部是珠江流域的重要生态屏障区之一，但一些区域在4月中下旬播种玉米，五月进入雨季。土壤结构的破坏、降水量显著增加和区域典型的喀斯特地貌导致坡耕地区域的水环境风险较高。研究通过采集原状土样，应用模拟降雨入渗实验探索喀斯特区域黄壤坡耕地在新翻耕后不同降雨强度下的胶体动态释放规律，包括胶体浓度、粒径分布及其动态特征。结果表明：胶体浓度呈现随降雨强度和累积雨量增加而增大外，并且所释放的土壤胶体浓度在3个雨强下的差异表现出3个不同阶段：0~100 mm阶段雨强为25 mm/h与40 mm/h时胶体浓度差异不显著，明显高于10 mm/h；100 ~ 250 mm阶段3个雨强下胶体浓度均有较大差异；累积雨量大于250 mm时三者差异小；胶体粒径的特征统计量在雨强为40 mm/h时呈明显的两阶段、突降特征，雨强为25 mm/h和10 mm/h时则呈现出渐变特征；不同粒径胶体含量变化分别呈现出稳定、增加和减小的趋势。研究揭示出不同流速下土壤胶体出流浓度差异的阶段性特征，并从细观尺度量化了不同粒径胶体随累积入渗量的含量变化趋势，将为进一步评价该时段的区域水环境风险和驱动机制提供参考依据。

It is a new problem for the prevention and control of non-point source pollution to adsorb pollutants by colloids and assist them to quickly migrate from soil to water during the rainfall-runoff process. Southwest Guizhou Province is one of the important ecological barrier areas in the Pearl River Basin, but some areas sow corn in the middle and late April and enter the rainy season in May. The destruction of soil structure, the significant increase of precipitation and the typical karst landforms in the region lead to high water environmental risks in sloping farmland areas. Undisturbed soil samples are collected from newly ploughed yellow soil slope farmland in karst area. These samples undergo simulated rainfall infiltration experiments. The purpose is to investigate the dynamic release rule of colloids under different rainfall intensities, including the change characteristics of colloid concentration, particle size distribution and its content level with the increase of accumulated rainfall. The results show as follows. The colloid concentration increased with the increase of rainfall intensity and cumulative infiltration, and the study further revealed that the difference of released soil colloid concentration under three rainfall intensities showed three different stages: the colloid concentration is not significantly different when the rainfall intensity is 25 mm/h and 40 mm/h in the 0 ~ 100 mm stage, but is significantly higher than 10 mm/h. The colloid concentration in the 100 ~ 250 mm stage is quite different under three rainfall intensities. When the accumulated rainfall is more than 250 mm, the difference between them is very small. When the rainfall intensity is 40 mm/h, the characteristic statistics of colloidal particle size show obvious two-stage and sudden drop characteristics. At first, the average particle size of effluent increases with the increase of rainfall intensity, and then decreases slightly with the further increase of rainfall. When the rainfall intensity is 25 mm/h and 10 mm/h, it presents a gradual change characteristic. The change of colloid content with different particle sizes shows a trend of stability, increase and decrease respectively. The research innovatively reveals the stage characteristics of the outflow concentration difference of soil colloids at different flow rates, and quantifies the change trend of colloids with different particle sizes with the cumulative infiltration from the meso-scale, which will provide a reference for further evaluating the regional water environmental risk and driving mechanism in this period.