岷江上游山高、谷深、坡陡 ,降水集中 ,土壤侵蚀严重。土壤侵蚀面积为 12 0 81.0 6 km2 ,占幅员面积的4 8.17% ;年土壤侵蚀量 3874 .86万 t。土壤侵蚀是由脆弱生态环境及人类社会经济活动 (砍伐森林、陡坡开垦、过度放牧及工程建设 )共同作用的结果 ,使土壤层变薄、肥力下降、水利工程淤积及寿命缩短、洪水灾害加剧。针对区域土壤侵蚀特点 ,提出了防治对策——制定科学的水土保持规划 ;搞好退耕还林还草工程 ;加强天然林保护工程及植树造林 ;控制牲畜数量 ,改良天然草地 ,治理退化草地 ;加强小流域综合治理 ;巩固和加强农田水利基本建设。

The upper reaches of Minjiang river has the characteristics of high mountains, deep valleys, steep slopes and concentrated rainfall. Soil erosion is severe. The erosion area is 12081.06 km2 and makes up 48.17% of the total area. The soil erosion amount is 3874. 86×104 töa. Here, the soil erosion is caused by fragile environment and human social-economic activities (forest cutting, steep slope land cultivat ing and over grazing engineering constructing). Soil erosion lead soil layer became thinner and its fertility reduced, irrigating works filled up and i s using time shortened, and the flood disaster increased. Based on the characteristics of soil erosion, proposed countermeasures to control soil erosion (working out scient if icplan of soil and water conservation; changing steep slope cultivated land to plant t rees and grow grasses; enhancing the project of preserving natural forest and tree planting; controlling livestock quantity, improving natural grassland and recovering degraded grassland; carrying out the comprehensive management of small valleys; so lidifying and strengthening the construction of farm land and irrigated works).