Journal of Resources and Ecology ›› 2015, Vol. 6 ›› Issue (3): 129-138.DOI: 10.5814/j.issn.1674-764x.2015.03.001

• Articles •     Next Articles

Effects of Simulated NH4+ Deposition on CO2 Fluxes in the Hulun Buir Meadow Steppe of Inner Mongolia, China

LIU Xingren1,2, ZHANG Leiming2, ZHANG Caihong3, REN Jianqiang4, LI Shenggong2   

  1. 1 Key Laboratory of Agricultural Environment, Ministry of Agriculture of P. R. China, Agricultural Clear Watershed Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
    2 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    3 School of Forestry, Shandong Agricultural University, Taian 271018, China;
    4 Key Laboratory of Agri-informatics, Ministry of Agriculture P. R. China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
  • Received:2014-07-03 Revised:2014-12-01 Online:2015-05-25 Published:2015-05-22
  • Contact: LI Shenggong. Email: lisg@igsnrr.ac.cn.
  • Supported by:

    the National Natural Science Foundation of China (Grant No. 31130009, 31300375) and the National Key Project of Scientific and Technical Supporting Program (Grant No. 2013BAC03B03).

Abstract:

Atmospheric nitrogen (N) deposition may affect carbon (C) sequestration in terrestrial ecosystem. The main objective of this paper was to test the hypothesis that N addition would increase CO2 emission in the N limited meadow steppe in Inner Mongolia, China. Response of CO2 fluxes to simulated N deposition was studied in the growing season of 2008 and 2009 by static chamber and gas chromatograph techniques. Parallel to the flux measurements, soil temperature, soil moisture, TOC, DOC, soil NH4+ and NO3- were measured at the same time. The results indicated that two-year N additions had no significant effect on NH4+, but slightly increased NO3- in the later period. The HN treatment tended to increase CO2 fluxes in the two years, and LN treatment tended to decrease CO2 fluxes in 2008, and shifted to increase CO2 fluxes in later growing season of 2009. N addition significantly increased the aboveground biomass and root biomass. The correlation between CO2 fluxes and moisture or temperature factors did not significantly change due to N addition, but N addition enhanced the moisture sensitivity of CO2 fluxes as well as the temperature sensitivity of CO2 fluxes. These results suggest that the increasing ammonium N deposition would be likely to stimulate CO2 fluxes in the meadow steppe of Inner Mongolia, China.