地理科学 ›› 2005, Vol. 25 ›› Issue (5): 606-613.doi: 10.13249/j.cnki.sgs.2005.05.606

• 论文 • 上一篇    下一篇

岩溶山区不同植被群落土壤生态系统特性研究

李阳兵1,2, 高明1, 邵景安1, 谢德体1, 魏朝富1   

  1. 1. 西南农业大学资源环境学院, 四川 重庆 400716;
    2. 贵州师范大学地理与生物科学学院, 贵州 贵阳 550001
  • 收稿日期:2004-06-07 修回日期:2004-12-24 出版日期:2005-09-20 发布日期:2005-09-20
  • 基金资助:
    重庆市科委项目(编号6759,7355)。

Changes of Soil Ecosystem in Karst Mountain Areas Under the Impact of Different Vegetations

LI Yang-Bing1,2, GAO Ming1, Shao Jing-An1, XIE De-Ti1, Wei Chao-Fu1   

  1. 1. Resources and Environment College, Southwest Agricultural University, Chongqing 400716;
    2. College of Geography and Biology Science, Guizhou Normal University, Guiyang, Guizhou 550001
  • Received:2004-06-07 Revised:2004-12-24 Online:2005-09-20 Published:2005-09-20

摘要: 自然植被演替成为次生植被、人工林或人工开垦利用后,岩溶山地土壤物理性能退化;沙化现象明显;坡耕地土壤长时间持水供水性能、抗旱性能降低;土壤种子库中草本种子比例大,木本植物种子少,土壤种子库退化更严重。研究区土壤有机质和全N受植被类型和土地利用强度影响明显,坡耕地土壤有机质较林草地系统低,退耕还林还草后,土壤有机质含量稳定增加。与自然植被相比,人工林、次生林系统土壤有机质含量仍较低。从弃耕地→灌草坡→次生林地的演替过程中,土壤种子库生态优势度呈降低趋势,物种丰富度和多样性增加。研究结果认为,岩溶生态系统土地退化的实质是土壤作为水库、养分库和土壤种子库功能的差异退化。

Abstract: In this study some typical karst mountainous regions in Chongqing were selected to discuss the essential characteristics of soil degradation during vegetation change processes. The results showed that: (1) After the vegetation turned into secondary vegetation or man-made vegetation, or reclamation, soils would be degraded in physical properties in the karst mountainous environment. Compared with the abandoned field, shrub-grassland, secondary forest and natural forest, in the surface soil layer of sloping cropland, the contents of >2 mm-sized water-stable aggregates dropped obviously to 52.1%, 24.7%, 29.9%, 22.8%, and those of 1mm-to 0.05 mm-sized particles increased, but those of 0.05mm-to 0.001mm-sized particles decreased, demonstrating apparent sandification; in slopping cropland soils, the capillary and aeration porosities, long-term soil water-retention and water-supplying capacities and soil resistance against drought were reduced as well, and their field water-holding capacity accounts for 79.3% of that of the forest land soils. (2) The contents of soil organic matter and total nitrogen are controlled completely by vegetation type and land-use intensity. The contents of SOM (soil organic matter) in sloping cropland are lower than in woodland and grassland. After the land was converted for forest and pasture, the contents of SOM would increase steadily, though this trend of increasing is rather slow in the early days when over-reclamation is stopped and the land is converted for forest and pasture. The contents of SOM in man-made woodland and secondary forestland are still lower than in natural forestland. (3) Herbaceous species increase and woody plants species decrease with increasing land use intensity, therefore, the soil seed banks degrade more seriously. With the process of evolution from abandoned field, shrub-grassland to secondary forestland, the ecological dominance will be reduced and the Richness index and diversity index will increase in soil seed banks. Based on the above research results, it is suggested that land degradation in the karst ecosystem is essentially characterized by the degradation of soil functions that are served as water banks, nutrient banks and soil seed banks, and the degradation rates of these three banks are different.

中图分类号: 

  • S154.1