不少学者指出,黄河下游淤积物中,粒径大于0.05mm的粗颗粒泥沙占69%,这部分泥沙在中游黄土中含量甚少,它们主要来自多沙粗沙区的基岩,因此加强易侵蚀基岩区的治理是关键.据最近的分析,发现黄河下游淤积物已明显细化,粒径≥0.05mm的粗泥沙占总淤积量的40%,0.05～0.025mm之间的泥沙约占30%,这部分泥沙来自黄土中的比例不小,因此在中游严重水土流失区应强调沟坡兼治. Many scholars pointed out that sediments in the lower reaches of the Yellow River accounted for 69% of the coarse-grained sediment with a diameter of more than 0.05mm. This part of sediment is very low in the middle loess and mainly comes from bedrock of the coarse-grained sand zone According to the recent analysis, the sediment in the lower Yellow River has been obviously refined, coarse sediment with the diameter of more than 0.05mm accounts for 40% of the total sediment, and the difference between 0.05 ~ 0.025mm Sediment about 30%, this part of the sediment from the proportion of loess is not small, so in the middle reaches of the serious soil erosion area should emphasize both governance and slope.