关键词: 全球变化, 土壤呼吸, 典型草原, 模拟增温与增雨

Abstract: In this study，authors conducted experiments for two growing seasons（2011 and 2012）in Stipa krylovii Steppe，Inner Mongolia，China Using open top chambers（OTCs）to simulate warming and precipitation enhancement.To study the effects of climate warming and increasing precipitation and the interaction on soil respiration of S krylovii Steppe.The results showed that：（1）both the diurnal change and daily variation pattern of soil respiration rate had a single peak，the highest respiration rate appeared in the 15：00pm in diurnal（2.26μmol·m-2·s-1）and late August in the growing season（5.51μmol·m-2·s-1）.Soil respiration rate of 9：00-11：00 can better represent the mean of all day.⑵Compared with the control，soil respiration rate reduced 19.0% when the air temperature increasing 1.91℃，but increased 18.6% under precipitation enhancement treatment（increase precipitation 20%）.Warming and precipitation enhancement treatment（increase air temperature 1.64℃，and increase precipitation 20%）increased 13.0% soil respiration rate compared with the control.（3）There were significant relationship among soil moisture，soil temperature and soil respiration rate.About 79% of soil respiration change was determined by the soil temperature and soil moisture，but the mainly influencing factor was soil moisture content（R2=0.797，P＜0.001）.Warming resulted in reduced soil moisture，indirectly led to the soil respiration rate decline.The results can provide the basis for the sustainable development of the science of climate change and the typical steppe grassland animal husbandry.

Key words: Global change, Soil respiration, Typical steppe, Warming and precipitation enhancement