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Evidence of a strong coupling between root exudation, C and N availability, and stimulated SOM decomposition caused by rhizosphere priming effects

Author:
  • Per Bengtson
  • Jason Barker
  • Sue J. Grayston
Publishing year: 2012
Language: English
Pages: 1843-1852
Publication/Series: Ecology and Evolution
Volume: 2
Issue: 8
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

Increased temperatures and concomitant changes in vegetation patterns are expected to dramatically alter the functioning of northern ecosystems over the next few decades. Predicting the ecosystem response to such a shift in climate and vegetation is complicated by the lack of knowledge about the links between aboveground biota and belowground process rates. Current models suggest that increasing temperatures and rising concentrations of atmospheric CO2 will be partly mitigated by elevated C sequestration in plant biomass and soil. However, empirical evidence does not always support this assumption, as elevated temperature and CO2 concentrations also accelerate the belowground C flux, in many cases extending to increased decomposition of soil organic matter (SOM) and ultimately resulting in decreased soil C stocks. The mechanism behind the increase has remained largely unknown, but it has been suggested that priming might be the causative agent. Here, we provide quantitative evidence of a strong coupling between root exudation, SOM decomposition, and release of plant available N caused by rhizosphere priming effects. As plants tend to increase belowground C allocation with increased temperatures and CO2 concentrations, priming effects need to be considered in our long-term analysis of soil C budgets in a changing environment. The extent of priming seems to be intimately linked to resource availability, as shifts in the stoichiometric nutrient demands of plants and microorganisms will lead to either cooperation (resulting in priming) or competition (no priming will occur). The findings lead us on the way to resolve the varying response of primary production, SOM decomposition, and release of plant available N to elevated temperatures, CO2 concentrations, and N availability.

Keywords

  • Biological Sciences
  • Carbon sequestration
  • coupled biogeochemical cycles
  • elevated CO2
  • global warming
  • microbial C assimilation
  • nitrogen mineralization
  • plant-microbial feedbacks
  • soil respiration

Other

Published
  • ISSN: 2045-7758
Per Bengtson
E-mail: per [dot] bengtson [at] biol [dot] lu [dot] se

Researcher

MEMEG

+46 46 222 37 60

E-F212

Sölvegatan 37, Lund

50

Research group

Microbial Ecology

Projects

Doctoral students and postdocs

PhD students, main supervisor

 

PhD students, assistant supervisor

Jian Li

Experimental setup