Abstract: In order to explore responses of the alpine ecological system on Qinghai-Tibetan Plateau to changes in snow-cover in line with the projection of global climate change, during the period from November 2010 to April 2012, ata the east edge of the Qinghai-Tibetan Plateau, in situ soil incubation in PVC tubes was conducted under snow covers, different in thickness (30, 50 and 100cm) for a set time period (60, 90 and 150d), and effects of the snow cover on soil microbial dynamics were monitored. It was found that the snow cover, 50 or 100cm thick, lowered biomass of soil microbes and population of soil fungi, but did not affect much to population of soil bacteria. Meanwhile, duration of snow cover did not cause any significant change in population and biomass of soil microbes, though early snow cover rendered the soil with relatively high temperature  and relatively fewer freeze-thaw cycles. However, the interaction between thickness and duration of a snow cover would significantly affect population and biomass of soil microbes (P<0.05). The soil under a snow cover 30cm in thickness for 90 days was significantly higher in biomass and population of soil microbes than that under a snow cover 50 or 100cm in thickness.

Key words: snow cover thickness, snow cover duration, soil microbe, Qinghai-Tibetan Plateau