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黄土高原广泛分布的坝地沉积泥沙中赋存了大量小流域侵蚀特征及侵蚀环境变化的信息,泥沙特性的变化则是这些信息的直接体现。该文通过对比分析淤地坝沉积旋回泥沙中和坝控小流域内不同泥沙源地土壤中有机质、全氮、全磷和全钾的含量,发现小流域内土壤养分含量变异性明显大于沉积旋回泥沙中的变异性,沉积旋回泥沙养分含量与沟壁土壤中的相接近,其中与沟壁中的全氮、全磷和全钾无显著差异(p>0.05),但显著小于荒草地和坡耕地中的有机质、全氮和全磷含量(p<0.05),表明淤地坝运行期间小流域泥沙主要来源于沟壁坍塌和沟道扩展,重力侵蚀和沟蚀是主要侵蚀类型;有机质和全氮在坝地沉积旋回中呈明显阶段性变化,分析认为其反映了农村土地联产承包责任制对小流域土地利用和土壤侵蚀的影响。
There are a large number of information about the erosion characteristics and erosion environment changes in sediment and sediment of dam land distributed widely in the Loess Plateau. Changes in sediment characteristics are the direct manifestation of these information. By comparing the contents of organic matter, total nitrogen, total phosphorus and total potassium in the sediment swirling sediments and the sediment control basins in the dam basin, it was found that the variability of soil nutrient contents in the small watershed was greater than that In the sedimentary cycle sediment, the nutrient content of the sedimentary cycle sediment is close to that of the soil in the ditch wall, and there is no significant difference (p> 0.05) with the total nitrogen, total phosphorus and total potassium in the ditch wall, but it is significantly less than The contents of organic matter, total nitrogen and total phosphorus (P <0.05) in the grassland and sloping farmland show that the sediment in the small watershed during the operation of the silt dam mainly comes from the ditch collapse and ditch expansion. Gravity erosion and gully erosion are the main erosions Type. The organic matter and total nitrogen changed obviously in the sedimentary cycle of the dam. The analysis shows that it reflects the impact of the contract responsibility system of rural land on the land use and soil erosion in the small watershed.