Evidence of a strong coupling between root exudation, C and N availability, and stimulated SOM decomposition caused by rhizosphere priming effects
| Autor: | Per Bengtson, Susan J. Grayston, Jason S. Barker |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
0106 biological sciences
Carbon sequestration elevated CO 2 microbial C assimilation Priming (agriculture) global warming 010603 evolutionary biology 01 natural sciences soil respiration Soil respiration Nutrient coupled biogeochemical cycles Ecosystem Nitrogen cycle Ecology Evolution Behavior and Systematics nitrogen mineralization Nature and Landscape Conservation Original Research 2. Zero hunger Rhizosphere Ecology Chemistry Soil organic matter plant–microbial feedbacks Biota 04 agricultural and veterinary sciences 15. Life on land 13. Climate action 040103 agronomy & agriculture 0401 agriculture forestry and fisheries |
| Zdroj: | Ecology and Evolution |
| ISSN: | 2045-7758 |
| Popis: | 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 CO(2) 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 CO(2) 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 CO(2) 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, CO(2) concentrations, and N availability. |
| Databáze: | OpenAIRE |
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