Record ID No. |
170 |
Author(s) |
Giardina C. P., Binkley D., Ryan M. G., Fownes J. H., Senock R. S. , 2004 |
Affiliation |
US Forest Service, USDA, N Cent Research Station, 410 MacInnes Dr, Houghton, MI 49931 |
Title |
Belowground carbon cycling in a humid tropical forest decreases with fertilization |
Source. Vol.(no):Page |
Oecologia. 139(4): 545-550 p. |
Categories |
Ectomycorrhiza |
Subjects |
Soil plant relations |
Sub-subjects |
Nutrition |
Host |
n.a. |
Organism |
n.a. |
Country |
U.S.A., North America |
Abstracts |
Only a small fraction of the carbon (C) allocated
belowground by trees is retained by soils in long-lived,
decay-resistant forms, yet because of the large magnitude of
terrestrial primary productivity, even small changes in C
allocation or retention can alter terrestrial C storage. The
humid tropics exert a disproportionately large influence over
terrestrial C storage, but C allocation and belowground
retention in these ecosystems remain poorly quantified. Using
mass balance and C-13 isotope methods, we examined the effects
of afforestation and fertilization, two land-use changes of
large-scale importance, on belowground C cycling at a humid
tropical site in Hawaii. Here we report that in unfertilized
plots, 80% of the C allocated belowground by trees to roots and
mycorrhizae was returned to the atmosphere within 1 year; 9% of
the belowground C flux was retained in coarse roots and 11% was
retained as new soil C. The gains in new soil C were offset
entirely by losses of old soil C. Further, while fertilization
early in stand development increased C storage in the litter
layer and in coarse roots, it reduced by 22% the flux of C
moving through roots and mycorrhizae into mineral soils. Because
soil C formation rates related strongly to rhizosphere C flux,
fertilization may reduce an already limited capacity of these
forests to sequester decay-resistant soil C.
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