高寒草甸土壤碳和氮及微生物生物量碳和氮对温度与降水量变化的响应

The Responses of Soil C and N,Microbial Biomass C or N under Alpine Meadow of Qinghai-Tibet Plateau to the Change of Temperature and Precipitation

为了分析气候变化对高寒草甸土壤碳氮循环的短期影响趋势,以野外控制试验方法分析高寒草甸土壤碳和氮及微生物生物量碳和氮对温度与降水量变化的响应趋势。结果显示:降水量变化对高寒草甸土壤有机碳含量影响不大,降水量不变,增温将使高寒草甸表层土壤有机碳含量减少,增温而降水量减少将使土壤底层全氮含量增加,增温而降水量不变将使土壤全氮含量减少。另外,增温对高寒草甸土壤微生物生物量碳和氮含量影响不大,增温而降水量减少将使底层土壤微生物生物量碳比例增加,降水减少或增加将使表层土壤微生物生物量所占氮比例增加。结果说明,高寒草甸土壤碳、氮及微生物生物量碳、氮对温度和降水量变化响应与温度和降水量变化交互作用及土层有关,短期内水热要素变化对土壤碳和氮含量及微生物生物量影响不大。

To know the effects of climate change on the soil organic carbon and total nitrogen content,the field controlling experiments of temperature and precipitation manipulation were constructed to analyze the responses of soil C or N,and microbial biomass C or N under alpine meadow to change of temperature and precipitation.The results showed that the change of precipitation would not cause a reducing in soil organic carbon（SOC）content under alpine meadows significantly（P 0.05）,while increasing temperature and no changing precipitation would cause decreasing in SOC content at surface soil layer,while increasing temperature and reducing precipitation would cause an increasing in total soil nitrogen content at deep soil layer,while increasing temperature and precipitation would cause a decreasing in total soil nitrogen content.Additionally,the change of precipitation or temperature would not cause a reducing of soil microbial biomass C or N content under alpine meadows significantly,while increasing temperature and reducing precipitation would cause total soil microbial biomass C ratio increasing,and increasing or decreasing precipitation would cause soil microbial biomass N ratio at soil layer increasing.The results indicated that the responses of soil C and N,microbial biomass C or N under alpine meadow to the change of temperature and precipitation were influenced by interaction between temperature and precipitation change or soil depth,and the effects of changing in temperature and soil water was not significantly.