黄土高原区为中华民族的主要发祥地,一部分原地和原下的冲积平原,土质比较肥沃,古谚中有“厥土黄壤,厥田上上”之说;由于历史上战乱对林草的破坏与不断砍伐,以致水土流失严重,战国时就曾有“泾水一石,其泥数斗”的记载,可能有些夸大。但以后情况越来越严重。由于植被破坏,生态失去平衡而引起的气候变化,雨量稀少 The Loess Plateau is the main cradle of the Chinese nation, part of the place and the original alluvial plain with relatively fertile soil. In the ancient proverbs, there are “yellow soil in the soil and upper in the field”, and the destruction of the forest and grass by the war in history Felling, resulting in serious soil erosion, the Warring States period had “a water Jing, the number of mud bucket,” the record may be somewhat exaggerated. However, the situation is getting worse afterwards. Due to vegetation damage, ecological imbalance caused by climate change, scarce rainfall