高山地区土壤微生物动态对雪况变化的响应

Response of Soil Microbial Dynamics to Changes in Snow Regime in Alpine Area

为探索全球变化驱动的雪被变化对青藏高原高山生态系统的影响,于2010年11月—2012年4月在青藏高原东缘地区采用PVC管原位培养土壤,研究不同最大积雪厚度(30、50和100 cm)和积雪周期(60、90和150 d)对土壤微生物动态的影响。结果表明,50和100 cm积雪覆盖降低了土壤微生物生物量和真菌数量(P<0.05),但未引起细菌数量的显著变化。同时,尽管较早的积雪使土壤有较高的温度和相对少的冻融循环,而不同积雪周期并没有引起土壤微生物数量和生物量的显著改变。但积雪厚度和积雪周期的交互作用可显著影响土壤微生物生物量和微生物数量(P<0.05)。当积雪周期为90 d时,最大积雪厚度30 cm时的土壤微生物数量和生物量均明显高于50和100 cm。

In order to explore responses of the alpine ecological system on Qinghai-Tibetan Plateau to changes in snowcover in line with the projection of global climate change,during the period from November 2010 to April 2012,at 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 100 cm） for a set time period （60,90 and 150 d）,and effects of the snow cover on soil microbial dynamics were monitored.It was found that the snow cover,50 or 100 cm 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 of 30 cm in thickness for 90 days was significantly higher in biomass and population of soil microbes than that under a snow cover of 50 or 100 cm in thickness.