Abstract: The mass fractions of soil nutrients for alpine meadows in Qinghai were measured to analyze their differentiation and relationships between soil nutrients and aboveground biomass at different altitudes (4056, 4221, 4263, 4293, 4332, 4427 m). Results indicated that the mass fractions of soil organic matter, total nitrogen, available nitrogen, available phosphorus and available potassium were higher at the first and sixth gradient, whereas were lower at the middle gradients. Total phosphorus content showed a stable pattern with the increase of altitude gradient. The plant aboveground biomass varied similarly with the total nitrogen, total potassium, available nitrogen and available potassium contents. There were significant positive correlations between biomass and total nitrogen, available potassium. Total nitrogen, soil organic matter, available nitrogen, available phosphorus and available potassium constituted the first principal component of affecting plant aboveground biomass. Total phosphorus and total potassium constituted the second principal component. These two principal components contributed 78.77% to the variance of aboveground biomass.

Key words: Aboveground biomass, Soil nutrient, Alpine meadow, Altitude gradient

摘要： 以青海省称多地区高寒草甸6个海拔梯度(4056,4221,4263,4293,4332,4427 m)样地为对象,通过测定土壤养分质量分数,研究了土壤养分随海拔梯度的变化规律及其与地上植物量的相关关系。结果表明:土壤有机质、全氮(N)、速效N、速效磷(P)、速效钾(K)的质量分数随海拔均呈"U"型分异趋势;土壤全P质量分数随海拔梯度的变化相对稳定;土壤全K、全N、速效N、速效K、速效P、土壤有机质的质量分数与地上植物量呈相似的变化趋势,其中,土壤全N、速效K与地上植物量成显著正相关(P<0.05)。土壤全N、土壤有机质、速效N、速效P和速效K是影响地上植物量的第1主成分,土壤全P和全K是第2主成分,累计贡献率为78.77%。

关键词: 地上植物量, 土壤养分, 高寒草甸, 海拔梯度