中文摘要：

土壤含水量和容重是土壤物理属性的2个重要指标,对土壤养分有效性及生产能力有重要影响。采用野外调查和室内分析法研究西藏当雄不同退化程度高寒草甸土壤水分和容重分布特征,为草地的科学管理和可持续利用提供理论依据。结果表明：不同区域环境及土壤条件对土壤水分含量分布及变异影响显著;随着草地退化程度加重,土壤含水量极显著降低（P〈0.01）,土壤容重显著增加（P〈0.05）;土壤含水量在土壤剖面上的变化表现为正常草地和轻度退化草地土壤0～10cm〉10～20cm,而严重退化草地为0～10cm〈10～20cm;土壤容重在土壤剖面上的变化表现为正常草地和轻度退化草地土壤容重0～10cm〈10～20cm,而严重退化区容重变化表现为0～10cm〉10～20cm。草地退化首先表现在表层土壤上,且草地退化导致土壤水分含量的显著降低也不利于草地的自然恢复,将加速草地的进一步退化。

英文摘要：

Soil water content and bulk density,which are two important soil physical properties,have a major effect on both soil nutrient validity and productivity.To provide a theoretic basis for lawn management and sustainable use,the distribution of soil water content and bulk density of degraded grassland at Dangxiong were studied using field survey and lab analyses.Results showed that environment and soil conditions significantly influenced soil water content.With the aggravation of grass degradation,soil water content decreased significantly while soil bulk density increased.Soil water content in 0~10 cm layer was higher than that in the 10~20 cm layer of both normal grassland and light degraded grassland,while soil water content in 0~10 cm layer was lower than that in the 10~20 cm layer of severely degraded grassland.Soil bulk density content in 0~10 cm layer was lower than that in the 10~20 cm layer of normal grassland and lightly degraded grassland,while soil bulk density content in 0~10 cm layer was higher than that in the 10~20 cm layer of severely degraded grassland.The grassland degraded on soil surface layer and the decrease of soil water content accelerated the degradation of grassland.