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Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 14, issue 17
Biogeosciences, 14, 3899-3908, 2017
https://doi.org/10.5194/bg-14-3899-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Ecosystem processes and functioning across current and future...

Biogeosciences, 14, 3899-3908, 2017
https://doi.org/10.5194/bg-14-3899-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 07 Sep 2017

Research article | 07 Sep 2017

Soil water regulates the control of photosynthesis on diel hysteresis between soil respiration and temperature in a desert shrubland

Ben Wang1,2,3, Tian Shan Zha1,2, Xin Jia1,2,3, Jin Nan Gong3, Charles Bourque4, Wei Feng1,2, Yun Tian1,2, Bin Wu1,2, Yu Qing Zhang1,2, and Heli Peltola3 Ben Wang et al.
  • 1Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, PR China
  • 2Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
  • 3School of Forest Sciences, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland
  • 4Faculty of Forestry and Environmental Management, University of New Brunswick, P.O. Box 4400, 28 Dineen Drive, Fredericton, New Brunswick, E3B 5A3, Canada

Abstract. Explanations for the occurrence of hysteresis (asynchronicity) between diel soil respiration (Rs) and soil temperature (Ts) have evoked both biological and physical mechanisms. The specifics of these explanations, however, tend to vary with the particular ecosystem or biome being investigated. So far, the relative degree of control of biological and physical processes on hysteresis is not clear for drylands. This study examined the seasonal variation in diel hysteresis and its biological control in a desert-shrub ecosystem in northwest (NW) China. The study was based on continuous measurements of Rs, air temperature (Ta), temperature at the soil surface and below (Tsurf and Ts), volumetric soil water content (SWC), and photosynthesis in a dominant desert shrub (i.e., Artemisia ordosica) over an entire year in 2013. Trends in diel Rs were observed to vary with SWC over the growing season (April to October). Diel variations in Rs were more closely associated with variations in Tsurf than with photosynthesis as SWC increased, leading to Rs being in phase with Tsurf, particularly when SWC>0.08m3m−3 (ratio of SWC to soil porosity = 0.26). However, as SWC decreased below 0.08m3m−3, diel variations in Rs were more closely related to variations in photosynthesis, leading to pronounced hysteresis between Rs and Tsurf. Incorporating photosynthesis into a Q10-function eliminated 84.2% of the observed hysteresis, increasing the overall descriptive capability of the function. Our findings highlight a high degree of control by photosynthesis and SWC in regulating seasonal variation in diel hysteresis between Rs and temperature.

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We examined the seasonal variation in diel hysteresis between soil respiration and temperature, and its controlling factors in a desert-shrub ecosystem. Our results indicated that soil water regulated the control of photosynthesis on diel soil respiration, causing seasonal variation in diel hysteresis. The results highlight the importance of biologically based mechanisms and the role of soil water in regulating diel hysteresis.
We examined the seasonal variation in diel hysteresis between soil respiration and temperature,...
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