黄土坡面结皮对土壤水稳性团聚体的稳定性和可蚀性的影响

为了探析微地形下土壤受雨滴打击后产生的结皮类型及团聚体组成差异。通过人工模拟降雨,研究坡面不同位置的结皮土壤水稳性团聚体分布特征、稳定性以及土壤可蚀性的变化情况。结果表明：（1）土壤水稳性团聚体以大团聚体（粒径>0.25 mm）含量为指标,原状土、结构结皮、沉积结皮、过渡带结皮>0.25 mm粒级的水稳性团聚体分别占37.28%、43.58%、36.69%、40.34%;（2）以降雨历时5 min为例,原状土、结构结皮、沉积结皮、过渡带结皮的水稳性团聚体的破坏率分别为：51.49%、46.00%、62.76%、51.02%;（3）原状土、结构结皮、沉积结皮、过渡带结皮的水稳性团聚体的平均重量直径分别为：0.15、0.20、0.14、0.17 mm;（4）原状土、结构结皮、沉积结皮、过渡带结皮土壤可蚀性K值的大小分别为：0.223、0.200、0.229、0.205。微地形下产生结皮差异使得水稳性团聚体分布有所区别,因此土壤水稳性团聚体稳定性和可蚀性存在差异。

Loess Slope Crust: Effects on the Stability and Erodibility of Soil Water-stable Aggregates

The paper aims to explore the crust types and the aggregates composition differences in micro-topographic soil attacked by raindrops. We studied the distribution characteristics, stability and soil erodibility of crust soil water-stable aggregates at different locations on slopes by simulated rainfall. The results showed that: (1) the water-stable aggregates of undisturbed soil, structural crust, sedimentary crust, transitional zone crust>0.25 mm were 37.28%, 43.58%, 36.69% and 40.34%, respectively; (2) taking the rainfall for 5 min as an example, the PAD of water-stable aggregates of undisturbed soil, structural crust, sedimentary crust and transitional zone crust were 51.49%, 46.00%, 62.76%, 51.02%, respectively; (3) the MWD of water-stable aggregates of undisturbed soil, structural crust, sedimentary crust and transitional zone crust were 0.15, 0.20, 0.14, 0.17 mm, respectively; (4) the erodibility K values of undisturbed soil, structural crust, sedimentary crust and transitional zone crust were 0.223, 0.200, 0.229, 0.205, respectively. The crust differences under micro-topography make the distribution of water-stable aggregates different, so the stability and erodibility of soil water-stable aggregates are different.