土地生产力退化是喀斯特生态系统产生石漠化的本质，但石灰土退化机理并不十分清楚。本项目以桂西北喀斯特地区为研究对象，采用点面结合的方法，基于210个网络样点、45个不同退化程度样方的调查与室内分析，揭示桂西北喀斯特地区石灰土不同退化程度的空间分布，探明石灰土不同退化程度植被与土壤属性的变异特征，建立桂西北喀斯特石灰土退化的危险度评价体系，找出影响石灰土不同退化程度的主要因子，阐明土壤侵蚀、土壤理化性状、土壤矿质养分、土壤微生物、植被、地形和人为干扰各集团因子之间的相互耦合关系，量化各集团因子对石灰土退化的贡献率，描绘土壤、植物属性沿石灰土退化梯度的分布规律，揭示植被和人为干扰对石灰土退化的作用机制，从而制定喀斯特退化生态系统恢复与重建的优化调控措施与途径，为桂西北喀斯特退化生态系统植被的迅速恢复和生态重建提供科学依据。

The degradation of land productivity was essential of rocky desertification forming process in karst region. However, the degradation mechanism of calcareous soil was poorly understood. The project takes the karst region in northwest of Guangxi as object and employs a method in combination with point and plane to build 210 meshed sample plots and 45 samples characterized with degeration levels. Based on the investigation and analysis, the project intends to analyze spatial distribution of calcareous soil with different degeneration degrees in the region, and to ascertain variation rules of vegetation and soil attibutes along calcareous soil degeration degrees. Then, risk evaluation system of calcareous soil degeration in karst region in northwest of Guangxi will be constructed. Multivariate statistical analysis is used to find out the main factors of influencing spatial pattern of calcareous soil with degeranation degrees, and to illuminate coupling relationships between soil erosion, soil physicochemical properties, soil mineral nutrients, soil microbes, vegetation, topography,and human disturbances, and then to quantify the contribution ratio of each group factors to degeranation of calcareous soil. Meanwhile, the distribution law of soil and vegetation along the degeration gradient of calcareous soil will be dipcted and the mechnism of vegetation and human disturbance to the degeranation of calcareous soil will be revealed. At last, it will set out optimizing regulation measures for restoration and reconstruction in karst regerated ecosystems. This would guide vegetation restoration and ecological rebuilding in the degenerated ecosystems in the karst region.