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| Titel |
Soil respiration on an aging managed heathland: identifying an appropriate empirical model for predictive purposes |
| VerfasserIn |
G. R. Kopittke, E. E. Loon, A. Tietema, D. Asscheman |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 5 ; Nr. 10, no. 5 (2013-05-06), S.3007-3038 |
| Datensatznummer |
250018235
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| Publikation (Nr.) |
 copernicus.org/bg-10-3007-2013.pdf |
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| Zusammenfassung |
| Heathlands are cultural landscapes which are managed through cyclical
cutting, burning or grazing practices. Understanding the carbon (C) fluxes
from these ecosystems provides information on the optimal management
cycle time to maximise C uptake and minimise C output. The interpretation of
field data into annual C loss values requires the use of soil respiration
models. These generally include model variables related to the underlying
drivers of soil respiration, such as soil temperature, soil moisture and
plant activity. Very few studies have used selection procedures in which
structurally different models are calibrated, then validated on separate
observation datasets and the outcomes critically compared. We present
thorough model selection procedures to determine soil heterotrophic
(microbial) and autotrophic (root) respiration for a heathland chronosequence
and show that soil respiration models are required to correct the effect of
experimental design on soil temperature. Measures of photosynthesis, plant
biomass, photosynthetically active radiation, root biomass, and microbial
biomass did not significantly improve model fit when included with soil
temperature. This contradicts many current studies in which these plant
variables are used (but not often tested for parameter significance). We
critically discuss a number of alternative ecosystem variables associated
with soil respiration processes in order to inform future experimental
planning and model variable selection at other heathland field sites. The
best predictive model used a generalized linear multi-level model with soil
temperature as the only variable. Total annual soil C loss from the young,
middle and old communities was calculated to be 650, 462 and
435 g C m−2 yr−1, respectively. |
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