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| Titel |
Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy covariance, biometric and continuous soil chamber measurements |
| VerfasserIn |
D. Zanotelli, L. Montagnani, G. Manca, M. Tagliavini |
| 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 (2013-05-07), S.3089-3108 |
| Datensatznummer |
250018240
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| Publikation (Nr.) |
 copernicus.org/bg-10-3089-2013.pdf |
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| Zusammenfassung |
Carbon use efficiency (CUE), the ratio of net primary production (NPP) over
gross primary production (GPP), is a functional parameter that could
possibly link the current increasingly accurate global GPP estimates with
those of net ecosystem exchange, for which global predictors are still
unavailable. Nevertheless, CUE estimates are actually available for only a
few ecosystem types, while information regarding agro-ecosystems is scarce,
in spite of the simplified spatial structure of these ecosystems that
facilitates studies on allocation patterns and temporal growth dynamics.
We combined three largely deployed methods, eddy covariance, soil
respiration and biometric measurements, to assess monthly values of CUE, NPP
and allocation patterns in different plant organs in an apple orchard during
a complete year (2010). We applied a measurement protocol optimized for
quantifying monthly values of carbon fluxes in this ecosystem type, which
allows for a cross check between estimates obtained from different methods.
We also attributed NPP components to standing biomass increments, detritus
cycle feeding and lateral exports.
We found that in the apple orchard, both net ecosystem production and gross
primary production on a yearly basis, 380 ± 30 g C m−2 and
1263 ± 189 g C m−2 respectively, were of a magnitude comparable to
those of natural forests growing in similar climate conditions. The largest
differences with respect to forests are in the allocation pattern and in the
fate of produced biomass. The carbon sequestered from the atmosphere was
largely allocated to production of fruit: 49% of annual NPP was taken
away from the ecosystem through apple production. Organic material (leaves,
fine root litter, pruned wood and early fruit falls) contributing to the
detritus cycle was 46% of the NPP. Only 5% was attributable to
standing biomass increment, while this NPP component is generally the
largest in forests.
The CUE, with an annual average of 0.71 ± 0.12, was higher than the
previously suggested constant values of 0.47–0.50. Low nitrogen investment
in fruit, the limited root apparatus, and the optimal growth temperature
and nutritional condition observed at the site are suggested to be
explanatory variables for the high CUE observed. |
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