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我国黄土高原的水土流失,举世瞩目。据调查估计,黄河年输沙量16亿吨,约有8亿吨来自坡耕地。按耕层20厘米推算,相当于每年损失500多万亩耕地。榆林地区平均每年每平方公里土壤侵蚀11,700吨,年侵蚀总量可达5.1亿吨。强烈的水土流失,不仅严重地破坏了土地资源和生态环境,造成了当地的贫困与落后,而且大量泥沙输入黄河,造成淤积严重,河床升高,导致了历史上多次决口改道,使下游人民的生命财产遭受巨大损失。
The soil and water loss of the Loess Plateau in China has attracted worldwide attention. According to survey estimates, the Yellow River annual sediment discharge of 1.6 billion tons, about 800 million tons from sloping fields. Calculated according to 20 cm plow, equivalent to more than 500 million mu of arable land loss each year. In Yulin area, the soil erosion is 11,700 tons per square kilometer per year on average, and the total annual erosion can reach 510 million tons. The intense soil erosion has not only seriously damaged the land resources and the ecological environment, resulting in poverty and backwardness in the area. The massive sediment input into the Yellow River caused serious siltation and riverbed rise, resulting in the repeated diversions in history and the downstream People’s lives and property suffered huge losses.