川江流域的土壤退化与防治

川江流域地区土壤退化按肥力因素分类，并以专家系统确定的指标分类统计表明：土壤物理性退化中以水分不调、过砂和板结化较严重；土壤结构性退化中，以土层浅薄化较显著；土壤营养性退化中，以缺硼、钼、磷较突出，成因主要是生态脆弱、土壤侵蚀作用和过渡开发利用，据此提出了防治退化的基本措施。并从持续发展角度提出了适应该区土壤退化特点的持续农业系统。

SOLL DEGRADATION AND ITS CONTROL IN THE CHUANJIANG RIVER VALLEY

Based on the factors of soil fertility. soil degradation has been calssified in the valley of the Chuanjing River and has quantitatively been studied according to the indexes determined by Expert System. The results show that in constrast with the middle and lower reaches of the Yangtze River and the whole country, in this region the incongruity of soil water, sandification and compactness of soil occur seriously in the respect of physical degradation, and soil layers are obviously thinned in the respect of contitutional degradation, and the deficiency of boron. molybdenum, as well as phosphorus take place generally in the respect of nutritional degradation. The causes of soil degradation are mainly due to frail ecological environment, soil erosion and undue utilization of land. The basic measures against soil degradation are put forward. A sustainable agriculture system is proposed to prevent soil degradation.