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我国现有25度以上的陡坡耕地约1亿亩,主要分布在西南、西北黄土高原和华南亚热带地区。陡坡地水土流失严重,以晋西黄土陡坡地带为例,25度以上的坡地每年流失表土厚度约1～1.5厘米,最高的达5～6厘米,年每亩流失的表土量达7～10吨。流失的每吨表土中约含全氮0.8～1.5公斤,全磷1.5公斤,全钾15～20公斤。严重的水土流失,一方面破坏了土地资源,使土壤肥力日趋下降,农业生产条件日益恶化;另一
There are about 100 million mu of steep slopes above 25 degrees in our country, mainly distributed in southwest, northwest Loess Plateau and South China subtropics. For example, in the steep slopes of the Loess Plateau, steep slopes of steep slopes have an annual loss of about 1 to 1.5 centimeters of topsoil and a maximum of 5 to 6 centimeters. The annual loss of topsoil per mu is 7 to 10 tons . The topsoil lost about 0.8 to 1.5 kg of total nitrogen, 1.5 kg of total phosphorus and 15 to 20 kg of total potassium. Serious soil erosion, on the one hand undermines the land resources, soil fertility is declining, aggravating agricultural production conditions; the other