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| Titel |
A two-layer application of the MAGIC model to predict the effects of land use scenarios and reductions in deposition on acid sensitive soils in the UK |
| VerfasserIn |
R. C. Helliwell, R. C. Ferrier, A. Jenkins |
| 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 ; 2, no. 4 ; Nr. 2, no. 4, S.497-507 |
| Datensatznummer |
250000647
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| Publikation (Nr.) |
 copernicus.org/hess-2-497-1998.pdf |
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| Zusammenfassung |
| A two-layer application of the catchment-based soil and
surface water acidification model, MAGIC, was applied to 21 sites in the UK Acid Waters
Monitoring Network (AWAMN), and the results were compared with those from a one-layer
application of the model. The two-layer model represented typical soil properties more
accurately by segregating the organic and mineral horizons into two separate soil
compartments. Reductions in sulphur (S) emissions associated with the Second S Protocol
and different forestry (land use) scenarios were modelled, and their effects on soil
acidification evaluated. Soil acidification was assessed in terms of base saturation and
critical loads for the molar ratio of base cations
(CA2+ + MG 2+ + K+)
to aluminium (Al) in soil solution. The results of the two-layer application indicate that
base saturation of the organic compartment was very responsive to changes in land use and
deposition compared with the mineral soil. With the two- layer model, the organic soil
compartment was particularly sensitive to acid deposition, which resulted in the critical
load being predicted to be exceeded at eight sites in 1997 and two sites in 2010. These
results indicate that further reductions in S deposition are necessary to raise the base
cation (BC):Al ratio above the threshold which is harmful to tree roots. At forested sites
BC:Al ratios were generally well below the threshold designated for soil critical loads in
Europe and forecasts indicate that forest replanting can adversely affect the acid status
of sensitive term objectives of protecting and sustaining soil and water quality. Policy
formulation must seek to protect the most sensitive environmental receptor, in this case
organic soils. It is clear, therefore, that simply securing protection of surface waters,
via the critical loads approach, may not ensure adequate protection of low base status
organic soils from the effects of acidification. |
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