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Park, Ji-Hyung ; Matzner, Egbert:
Carbon control on nitrogen dynamics in the forest floor of an N-enriched deciduous forest ecosystem.
In: Water, Air, & Soil Pollution.
Bd. 130
(2001)
Heft 1-4
.
- S. 643-648.
ISSN 1573-2932
DOI: https://doi.org/10.1023/A:1013800611498
Abstract
Recent evidence from nitrogen (N) saturation studies indicates that forest floors in moderately impacted forests are the primary sink for atmospheric N inputs. Some researchers have suggested that the sink capacity of organic horizons is dependent on the amount of available carbon (C), which can be used for microbial N assimilation. To test the hypothesis that C limitation in forest floors exposed to chronic N deposition leads to an enhanced N leaching, a field C input manipulation experiment is under way in a deciduous forest. Since September 1999 aboveground C input has been doubled (by doubling litter input or by amending glucose) or excluded in replicated plots. Here we report the short-term response of concentrations of dissolved inorganic N (DIN: NO3--N and NH4+-N) in forest floor percolate to the C input manipulation. In autumn following the C input manipulation, DIN concentrations in forest floor percolate decreased in all plots except the No Litter plots compared to the pre-treatment summer concentrations. In contrast, the concentrations of DIN in the No Litter plots remained high. A different seasonal pattern of DIN leaching among treatments, along with measurements of microbial biomass C and potential nitrification rates of forest floor samples, indicates that seasonal N dynamics in the forest floor are largely regulated by C availability changes associated with litterfall C input.