摘要
我国南方土地退化的形成是由其生态环境的脆弱性决定的。土地退化不仅表现为土壤退化,还表现为植被退化和土地状况恶化,具有明显的坡面分带性。从50 年代到80 年代,不同人类活动地区土地退化变化的特点不同。土地退化的动态变化主要是由于土地的开垦及人类活动对植被的破坏。土地退化严重的地区既不是人口较少和经济落后的基岩山区,也不是人口较密、经济发达的低丘岗地区,而是人口增长较快、经济较落后的低山丘陵区。
Three experimental plots were chosen for study on genesis, symptoms and spatial and temporal change of land degradation in subtropical hill and mountain regions of South China. Land degradation, caused by water erosion, closely related to the inherent vulnerabilities of its ecological environment.Spatial variation of land degradation from top to foot along the slope was mainly induced by differentiation of surface material and their properties of erodibility, nutrient and moisture due to downslope variation of soil erosion. Land degradation manifests itself not only soil degradation but also vegetation degradation and deterioration of land surface. Comparison between land degradation maps of 1950s and 1980s showed that temporal changes of land degradation were different from one area to another because of differences of human activities. Changes of land degradation were mainly attributed to reclamation of land and depletion of vegetation led by adverse human activities. Most severe land degradation took place neither in the less populated and less developed mountain area nor in the densely populated and more developed undulating hill area, but in the low mountain and hill area, where increase of population is more quick but economy less developed.
基金
国家自然科学基金!资助项目(49671078)
