This study investigates an underground biomass variation of Poa pratensis var.anceps Gaud.cv.Qinghai over a six-year period.Further,it reveals intraspecies competition characteristics of rhizome plants and provides basic data for both species adaptation and an ecological balance system maintaining.Results showed the highest underground biomass in 0~5 cm,but concentrated in 0~20 cm.Vertical distribution of underground biomass appeared as T shape.Seasonal variation of underground biomass in two years showed a...