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| Titel |
Long-term nitrogen addition decreases carbon leaching in a nitrogen-rich forest ecosystem |
| VerfasserIn |
X. Lu, F. S. Gilliam, G. Yu, L. Li, Q. Mao, H. Chen, J. Mo |
| 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. 6 ; Nr. 10, no. 6 (2013-06-18), S.3931-3941 |
| Datensatznummer |
250018293
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| Publikation (Nr.) |
 copernicus.org/bg-10-3931-2013.pdf |
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| Zusammenfassung |
| Dissolved organic carbon (DOC) plays a critical role in the carbon (C) cycle
of forest soils, and has been recently connected with global increases in
nitrogen (N) deposition. Most studies on effects of elevated N deposition on
DOC have been carried out in N-limited temperate regions, with far fewer
data available from N-rich ecosystems, especially in the context of
chronically elevated N deposition. Furthermore, mechanisms for excess
N-induced changes of DOC dynamics have been suggested to be different
between the two kinds of ecosystems, because of the different ecosystem N
status. The purpose of this study was to experimentally examine how
long-term N addition affects DOC dynamics below the primary rooting zones
(the upper 20 cm soils) in typically N-rich lowland tropical forests. We
have a primary assumption that long-term continuous N addition minimally
affects DOC concentrations and effluxes in N-rich tropical forests.
Experimental N addition was administered at the following levels: 0, 50, 100
and 150 kg N ha−1 yr−1, respectively. Results showed that seven
years of N addition significantly decreased DOC concentrations in soil
solution, and chemo-physical controls (solution acidity change and soil
sorption) rather than biological controls may mainly account for the
decreases, in contrast to other forests. We further found that N addition
greatly decreased annual DOC effluxes from the primary rooting zone and
increased water-extractable DOC in soils. Our results suggest that long-term
N deposition could increase soil C sequestration in the upper soils by
decreasing DOC efflux from that layer in N-rich ecosystems, a novel
mechanism for continued accumulation of soil C in old-growth forests. |
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