Abstract: The study takes a meadow’s secondary productivity to assess if it is degrading,and takes the amount of the meadow’s aboveground biomass or rate of high-quality grass yield as the major factors that influence the secondary productivity.The benchmark that denotes the transitional period of a meadow’s degradation is that its biomass of high-quality grass falls with an annual speed of 1%～5%.The result shows that normally it takes 51 years,the longest,for a plot of meadow to degrade severely and the shortest 10.2 years to deteriorate seroiusly.At present,the annual average degradation rate of the total Qinghai meadow acreage is 2.42%.

Key words: Grassland science, Grassland degradation, Forecast model, Kobresia meadow

摘要： 以次级生产力作为衡量草地退化的标准,以生物量或优良牧草比例作为影响次级生产力的主要因子,建立嵩草草地退化预测模型;以优良牧草生物量下降1%～5%的速度预测不同程度退化草地之间的过渡时间,结果表明:未退化草地演替至重度退化草地所需时间,最长为51年,最短仅10.2年。目前,青海省草地的平均退化速度为2.42%。

关键词: 草原学, 草地退化, 预测模型, 嵩草草甸