土地退化不仅是目前全还需性的重大环境问题之一，而且也是重大的社会和经济问题之一，西南地区的土地退化是以水力侵蚀为主要动力形成的，文中简述了西南地区的土地退化状况，选择了4个（楚雄市、遂宁市，毕节地区及元谋县）山地不同土地退化类型进行分析，讨论了土 退化过程，提出了土地退化调控途径。

Land degradation is not only a great environmental problem at present，but a great economic and social problem．Land degradation in southwest China is mainly formed by water erosionThis paper，briefly descibed the land degradation status (slight，moderate and severe degraded land area is respectively 188852．5，48128．81 and 16．393．62 km．and respectively makes uD l4．30％ ，3．50％ and 1．1O％ of the Iota1 area of southwest China)in southwest China．analyzed different land degradation types of 4 choeaed areas(Chuxiong City in Yunnan Plateau(degraded area is 1 1 59．44 km2 and makes up 26．17％ of the Iota1 area)．Suining City in hilly area in middle Sichuan Basin(degraded area is 3 188．51 km2+makes up 59．93％ of the total area)，Bijie Prefecture in lime stone areainGuizhou Province(degraded areaiS 9055．30 k ，makes up 33．70％ ofthetotal area)and Yuanmou County in dry—hot valley in Yunnan Province(degraded area below 1350m of altitude is 1006．02 km ，makes up 70．15％ of the total area))，discussed land degradation process(The land degradation process is under fragile t(great height difference，steep slope，frequent heavy rain and rain storm)，human unreasonable socia1．economic activity(reclaim slope land，Cut forest，over grazing，etc．)∞ ed the proce~of land degradation)，pI℃ ways(prevention and control of land degradation by the law；strictly mnlrol popu·
lation withtheN rall~ ofthe equation：0．2113K