Can composition and physical protection of soil organic matter explain soil respiration temperature sensitivity?

Zimmermann, Michael, Leifeld, Jens, Conen, Franz, Bird, Michael I., and Meir, Patrick (2012) Can composition and physical protection of soil organic matter explain soil respiration temperature sensitivity? Biogeochemistry, 107 (1-3). 423- 436.

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Abstract

The importance of soil organic matter (SOM) in the global carbon (C) cycle has been highlighted by many studies, but the way in which SOM stabilization processes and chemical composition affect decomposition rates under natural climatic conditions is not yet well understood. To relate the temperature sensitivity of heterotrophic soil respiration to the decomposition potential of SOM, we compared temperature sensitivities of respiration rates from a 2-year long soil translocation experiment from four elevations along a ~3000 m tropical forest gradient. We determined SOM stabilization mechanisms and the molecular structure of soil C from different horizons collected before and after the translocation. Soil samples were analysed by physical fractionation procedures, 13C nuclear magnetic resonance (NMR) spectroscopy, and differential scanning calorimetry (DSC). The temperature sensitivity (Q 10) of heterotrophic soil respiration at the four sites along the elevation transect did not correlate with either the available amount of SOM or its chemical structure. Only the relative distribution of C into physical soil fractions correlated with Q 10 values. We therefore conclude that physical fractionation of soil samples is the most appropriate way to assess the temperature sensitivity of SOM.

Item ID: 17758
Item Type: Article (Research - C1)
ISSN: 1573-515X
Keywords: soil organic matter; Q10; fractionation; 13C nuclear magnetic resonance; differential scanning calorimetry
Date Deposited: 11 Aug 2011 05:24
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050301 Carbon Sequestration Science @ 50%
05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050304 Soil Chemistry (excl Carbon Sequestration Science) @ 50%
SEO Codes: 96 ENVIRONMENT > 9614 Soils > 961403 Forest and Woodlands Soils @ 100%
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