中文摘要：

为探索三江源区草地退化过程中植被与土壤养分之间的关联性,对果洛州玛多县花石峡地区不同退化梯度草甸的植被特征和土壤养分进行了相关性分析。结果表明：在山地草甸梯度退化过程中,优质牧草丰富度、盖度均降低,低产杂草类植被比例增加;随着退化梯度加剧和土壤剖面加深,土壤养分梯度变化明显,有机质含量明显下降,土壤呈碱化趋势,速效磷含量下降。植被盖度与土壤速效磷、p H值、有机质含量呈高度关联性。有机质和磷肥是植被恢复重建的关键。

英文摘要：

In order to study the relevance between vegetation and soil nutrient in the degradation of the mountain meadow at Three River Source region,Qinghai Province,China,analysis of correlation between vegetation characteristics and soil nutrients were carried out on different degraded meadow in Huashi area of Maduo County of Golog Prefecture. The results showed that： in the degradation process,high-quality grass richness and coverage decreased,such as Kobresia pgymaea,while the proportion of low class weed increased,such as Leontopodium alpinum and Artemisia stelleriana. With the aggravation of degraded mountain meadow and increment of soil depth,there were significantly gradient changes for soil organic matter,p H value and available phosphorus. Organic matter decreased significantly. Content of organic matter of non-,mild-,moderate- and severe-degraded meadow were 52.12 g·kg^-1,36.02 g·kg^-1,25.54 g·kg^-1,13.36 g·kg^-1in top 0^-10 cm layers,which had declined to 20.80 g·kg^-1,25.92 g·kg^-1,13.67 g·kg^-1,12.55 g·kg^-1in the 20-30 cm layers. The soil was alkalized,and soil p H value was 6.88 at non-degraded alpine meadow,while soil p H value was above 8 at moderate- and severe-degradation meadow. The soil p H value increased gradually with the increase of soil depth. Available phosphorus decreased significantly. Content of available phosphorus of non-,mild-,moderate- and severe-degraded meadow were 27.13 mg·kg^-1,14.12 mg·kg^-1,9.26 mg·kg^-1,5.46 mg·kg^-1at top 0^-10 cm layers,while those values had declined to 16.13 mg·kg^-1,10.88 mg·kg^-1,1.97 mg·kg^-1,4.46 mg·kg^-1at the 10-20 cm layers. There were high correlation between vegetation coverage and available phosphorus,p H and organic matter,and associated value were 0.944 8,-0.979 9,0.898 2. The two previous data reached significant level. Available P and organic matter are the key factors affecting the growth of vegetation. The innovation and high light of this paper is the discussion about the effect of available phosphorus,p H and organic matter