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| Titel |
Fine root dynamics for forests on contrasting soils in the Colombian Amazon |
| VerfasserIn |
E. M. Jimenez, F. H. Moreno, M. C. Peñuela, S. Patiño, J. Lloyd |
| 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 ; 6, no. 12 ; Nr. 6, no. 12 (2009-12-03), S.2809-2827 |
| Datensatznummer |
250004215
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| Publikation (Nr.) |
 copernicus.org/bg-6-2809-2009.pdf |
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| Zusammenfassung |
| It has been hypothesized that as soil fertility increases, the amount of
carbon allocated to below-ground production (fine roots) should decrease. To
evaluate this hypothesis, we measured the standing crop fine root mass and
the production of fine roots (<2 mm) by two methods: (1) ingrowth cores
and, (2) sequential soil coring, during 2.2 years in two lowland forests
growing on different soils types in the Colombian Amazon. Differences of
soil resources were defined by the type and physical and chemical properties
of soil: a forest on clay loam soil (Endostagnic Plinthosol) at the
Amacayacu National Natural Park and, the other on white sand (Ortseinc
Podzol) at the Zafire Biological Station, located in the Forest Reservation
of the Calderón River. We found that the standing crop fine root mass
and the production was significantly different between soil depths (0–10 and
10–20 cm) and also between forests. The loamy sand forest allocated more
carbon to fine roots than the clay loam forest with the production in loamy
sand forest twice (mean±standard error=2.98±0.36 and 3.33±0.69 Mg C ha−1 yr−1, method 1 and 2,
respectively) as much as for the more fertile loamy soil forest (1.51±0.14,
method 1, and from 1.03±0.31 to 1.36±0.23 Mg C ha−1 yr−1,
method 2). Similarly, the average of standing crop fine root mass was higher in the white-sands forest
(10.94±0.33 Mg C ha−1) as compared to the forest on the
more fertile soil (from 3.04±0.15 to 3.64±0.18 Mg C ha−1).
The standing crop fine root mass also showed a temporal
pattern related to rainfall, with the production of fine roots decreasing
substantially in the dry period of the year 2005. These results suggest that
soil resources may play an important role in patterns of carbon allocation
to the production of fine roots in these forests as the proportion of carbon
allocated to above- and below-ground organs is different between forest
types. Thus, a trade-off between above- and below-ground growth seems to
exist with our results also suggesting that there are no differences in
total net primary productivity between these two forests, but with higher
below-ground production and lower above-ground production for the forest on
the nutrient poor soil. |
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