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| Titel |
Quantification of nitrate leaching from forest soils on a national scale in The Netherlands |
| VerfasserIn |
J. Kros, A. Tietema, J. P. Mol-Dijkstra, W. Vries |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 8, no. 4 ; Nr. 8, no. 4, S.813-822 |
| Datensatznummer |
250005736
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| Publikation (Nr.) |
 copernicus.org/hess-8-813-2004.pdf |
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| Zusammenfassung |
| To evaluate the effects of nitrogen (N) emission policies,
reliable information on nitrate concentrations and leaching fluxes from forest
ecosystems is necessary. Insight into the regional variability of nitrate concentrations,
to support local policy on emission abatement strategies is especially desirable.
In this paper, three methods for the calculation of a spatial distribution of
soil nitrate concentrations in Dutch forest ecosystems are compared. These are
(i) a regression model based on observed nitrate concentrations and additional
data on explanatory variables such as soil type, tree species and nitrogen deposition
(ii) a semi-empirical dynamic model WANDA, and (iii) a process-oriented dynamic
model SMART2. These two dynamic models are frequently used to evaluate the effects
of reductions in nitrogen deposition at scales ranging from regional to countrywide.
The results of the regression model evaluated the performance of the two dynamic
models. Furthermore, the results of the three methods are compared with the
steady-state approach currently used for the derivation of nitrogen critical
loads. Both dynamic models, in the form of cumulative distribution functions,
give similar results on a national scale. Regional variability is predicted
differently by both models. Discrepancies are caused mainly by a difference
in handling forest filtering and denitrification. All three methods show that,
despite the high nitrogen inputs, Dutch forests still accumulate more N than
they release. This implies that, in respect of groundwater quality, presently
acceptable nitrogen deposition is higher than the (long-term) critical loads.
However, in areas with high atmospheric nitrogen input, all three methods indicate
that the EU standard for nitrate in groundwater (50 mg NO3 l–1)
is exceeded. Steady-state with nitrogen deposition seems to have been reached
in about 10% of the forested area, with a nitrate concentration greater than
50 mg NO3–1.
Keywords: soil modelling, up-scaling, model validation, critical load |
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