水蚀风蚀交错带小流域淤地坝泥沙沉积特征

淤地坝泥沙沉积特征是小流域土壤侵蚀及坝地内泥沙运移沉积过程的信息载体。通过对水蚀风蚀交错带典型坝地内不同剖面中泥沙沉积旋回厚度及粒径组成变化的分析，初步探讨了坝地内泥沙沉积空间分布特征及对小流域土壤侵蚀和泥沙运移沉积过程的响应。结果表明:坝地泥沙沉积旋回厚度从坝尾到坝前呈现不均匀变化，但沉积旋回厚度总体呈逐渐变薄的趋势，沉积旋回中沙层厚度普遍大于粘层厚度；坝地内不同剖面沉积旋回泥沙主要由细砂粒组成，其平均含量为59.8%，其次为粉砂粒（23.4%），黏粒（11.2%）和粗砂粒（5.6%）含量较少；从坝前到坝尾各个剖面中沉积泥沙颗粒组成粗化度逐渐增大，且沉积旋回中沙层的粗化度变化大于粘层的变化。初步揭示了淤地坝沉积泥沙从坝尾到坝前的沉积规律，可以为以后相关工作的开展提供参考。

Characteristics of Sediment in Check Dam of Small Watershed in Wind-Water Erosion Cross Region

Check dam and sediment deposition characteristics play the important role in studying the progress of eroded sediment migration and characteristics. In this paper, we analyzed the thickness and grain composition of sediment in different soil profiles in check dam in wind-water erosion cross region, we discussed the spatial distribution characteristics of sediment, and its response to soil erosion and sediment transport process. The results show that the sediment presents a non-uniform change from the tail to the front of the dam, but the layers of sedimentary cycle gradually becomes thin as a whole, the thickness of the sandy layer is generally greater than that of the clayey layer; the sediment in different location of dam is mainly composed of the fine sand, the average content of fine sand is 59.77%, followed by silt (23.41%), clay (11.21%), coarse sand (5.62%); deposition of sediment particles gradually become coarse from the tail to the front of the dam, and coarsening degree becomes greater, the coarsening degree of sand horizon is bigger than that of the clayey layer.