Chin J Plan Ecolo ›› 2018, Vol. 42 ›› Issue (1): 105-115.DOI: 10.17521/cjpe.2017.0164

• Research Articles • Previous Articles     Next Articles

Responses of soil N2O emissions to experimental warming regulated by soil moisture in an alpine steppe

WANG Guan-Qin1,2,LI Fei1,2,PENG Yun-Feng1,CHEN Yong-Liang1,HAN Tian-Feng1,YANG Gui-Biao1,2,LIU Li1,2,ZHOU Guo-Ying3,YANG Yuan-He1,2,*()   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China

    2University of Chinese Academy of Sciences, Beijing 100049, China; and 3Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
  • Online:2018-01-20 Published:2018-01-18
  • Contact: Yuan-He YANG
  • Supported by:
    Supported by the National Natural Science Foundation of China(41371213);Supported by the National Natural Science Foundation of China(41501265)

Abstract:

Aims Nitrous oxide (N2O) is one of the most important greenhouse gases, which contributes a lot to global warming. However, considerable variations are observed in the responses of soil N2O emissions to experimental warming, and the underlying microbial processes remain unknown.

Methods A warming experiment based on open-top chambers (OTCs) was set up in a typical alpine steppe on the Qinghai-Xizang Plateau. The static chamber combined gas chromatography method was applied to investigate soil N2O flux under control and warming treatments during the growing seasons in 2014 and 2015. Gene abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were quantified using quantitative real-time PCR.

Important findings Our results showed that the warming treatments increased soil temperature by 1.7 and 1.6 °C and decreased volumetric water content by 2.5% and 3.3% respectively during the growing season (May to October) in 2014 and 2015. However, there were no significant differences in other soil properties. Our results also revealed that, the magnitude of soil N2O emissions exhibited substantial variations between the two experimental years, which were 3.23 and 1.47 μg·m -2·h -1in 2014 and 2015, respectively, but no significant difference in N2O fluxes was observed between control and warming treatments. AOA and AOB abundances are 15.2 × 10 7and 10.0 × 10 5copies·g -1 in 2014, and 5.0 × 10 7and 4.7 × 10 5copies·g -1in 2015, with no significant differences between control and warming treatments during the experimental period. Furthermore, warming-induced changes in N2O emissions had no significant relationship with the changes in soil temperature, but showed a significant positive correlation with the changes in soil moisture at seasonal scale. Overall, these results demonstrate that soil moisture regulates the responses of N2O emissions to experimental warming, highlighting the necessity to consider the warming-induced drying effect when estimating the magnitude of N2O emissions under future climate warming.

Key words: climate warming, nitrous oxide, ammonia-oxidizing archaea, ammonia-oxidizing bacteria, Qinghai-?Xizang Plateau