退化演替对高山草地植被和土壤理化特性影响

目的]分析3种不同草地退化阶段(轻度退化,中度退化和重度退化)草地植被和土壤理化特性的变化规律,为类似区域退化草地植被恢复提供有效途径。方法]野外植被调查、土壤取样和室内分析。结果]草地退化不同阶段草地植物群落组成和物种多样性均有差异,退化对草地土壤理化特性有明显影响。重度退化草地土壤容重显著高于轻度退化草地(p0.05)。轻度和中度退化样地0—10cm土壤空隙度显著高于重度退化草地。重度退化草地的土壤有机质、全碳、全钾、全磷和有效钾均明显小于轻度退化草地(p0.05),但土壤pH值和有效氮含量没有显著变化。结论]高山草地退化演替对该区土壤物理特性具有显著影响。

Effect of Degradation Succession on Vegetation and Soil Physical and Chemical Characteristics in Alpine Grassland

Objective] The changes of soil physical and chemical properties in three levels of degraded grasslands(light degradation grasslands, middle degradation grasslands and heavy degradation grasslands) in alpine grassland in the Qilian Mountain were studied to provide references for the restoration of grasslands in analogous area. Methods] Vegetation investigation and soil sampling were conducted and the samples were assayed. Results] Obvious differences were observed in community composition and species diversity. The soil physical and chemical properties under different degraded grasslands were affected by degradation level. The soil bulk density in the heavy degraded grassland was significantly higher(p<0.05) than that of light degraded grassland. The content of soil total porosity of 0-10 cm layer in light degradation grassland was significantly higher than that of heavy degraded grassland. The contents of organic matter, total K, total P and available K in heavy degraded grassland were obviously lower(p<0.05) than those of lighter degraded grassland, but there were no significant differences in the content of pH value and available N. Conclusion] Soil physical and chemical characteristics were significantly affected by vegetation degraded succession in alpine grassland.