一、黔西北地区水土流失的新发展黔西北地区处于云贵高原向黔中山原过渡地带,地势西高东低,有高原、山地、丘陵、盆地、河谷等多种地貌类型,海拔在1000～2400米之间,年降水量为1000～1200毫米。该地区资源丰富,气候条件较为优越,蕴藏着巨大生产潜力。然而,由于山高坡陡,降水量大和森林资源的减少,垦殖程度的增高,水土流失日趋严重。在1964年全省水土流失普查中,黔西北的毕节和六盘水两地区的流失面积约占总土地面积的30％左右,到1983年仅毕节地区的八个县平均已达总面积的40.6％。水土流失严重的赫章、纳雍县流失面积达50％以上。1959年前全区平均每平方公里土壤流失量为 I. New Development of Soil and Water Loss in Northwest Guizhou In the transitional zone of Yunnan-Guizhou Plateau to Central Guizhou, the terrain is high in the west and low in the east. There are many types of landforms such as plateaus, mountains, hills, valleys and valleys, with elevations of 1,000 to 2,400 meters Between, the annual precipitation is 1000 ~ 1200 mm. The region is rich in resources and enjoys superior climatic conditions, which holds great potential for production. However, due to the steep mountain slopes, large amount of precipitation and the reduction of forest resources and the increase of reclamation, soil and water loss is becoming more and more serious. In the 1964 general survey of soil and water loss in the province, the loss of Bijie and Liupanshui areas in northwestern Guizhou accounted for about 30% of the total land area. By 1983, only eight counties in Bijie Prefecture had an average of 40.6% of the total area. Hezhang serious soil erosion, Nayong County, the loss of more than 50%. Before 1959, the average soil loss per square kilometer in the whole region was