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Acta Prataculturae Sinica ›› 2015, Vol. 24 ›› Issue (4): 21-29.DOI: 10.11686/cyxb20150403

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The influence of hydrothermal factors on soil respiration and soil temperature sensitivity of Stipa krylovii steppe, Inner Mongolia, China

GU Rui1,2, CHAO Luo-Meng1*, ZHANG Li-Xin1,2, SU Li-De1,2, WAN Zhi-Qiang1,2, YAN Yu-Long1,2, CHEN Ya-Li1,2, GAO Qing-Zhu2*   

  1. 1.School of Life Sciences, Inner Mongolia University, Hohhot 010021, China;
    2. Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory for Agro-Environment & Climate Change of Ministry of Agriculture, Beijing 100081, China
  • Received:2014-10-13 Revised:2014-12-10 Online:2015-04-20 Published:2015-04-20

Abstract: The grasslands of the Inner Mongolian Stipa krylovii steppe make an important contribution to animal production in China. Soil respiration is an important component of the carbon cycle on the steppe and the main source of soil carbon losses. In this study, typical grassland dominated by S. krylovii, located in Maodeng Ranch, Xilinhaote, Inner Mongolia was selected as the study area. An open top type growth chamber was used to simulate the response of soil respiration to temperature and precipitation from 2011 to 2013. The Automated Soil CO2 Flux System (LI-8100, LI-COR, NE) was used to observe the soil respiration in the study area during the growing season (May to September). Air temperature, soil temperature and soil moisture were measured using the EM50 Data Collection System (Decagon Devices, Inc., NE, USA). Soil samples were collected, soil nutrients and microbial numbers were determined and correlation analysis used to explore associations between soil respiration rate and environmental factors. Soil respiration was significantly affected by air temperature and soil water content (P<0.01). Under warm and warm-moist conditions respectively soil respiration rates were 2.60 μmol/(m2·s) and 1.96 μmol/(m2·s) (2012) and 3.38 μmol/(m2·s) and 2.09 μmol/(m2·s) (2013); differences between years were significant (P<0.05). Increased air temperature and decreased soil water content both inhibited soil respiration. During the 2013 growing season additional environmental factors including soil organic carbon, total nitrogen and soil microbial mass may also have affected soil respiration. The Q10 temperature coefficient was significantly increased by warm-moist conditions. It was concluded that soil respiration is mainly influenced by hydrothermal conditions; increased air temperature and reduced soil moisture content inhibit soil respiration. The relationship between environment factors and soil respiration on the Inner Mongolian steppe is complex and requires further research.