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| Titel |
Spatialized N budgets in a large agricultural Mediterranean watershed: high loading and low transfer |
| VerfasserIn |
L. Lassaletta, E. Romero, G. Billen, J. Garnier, H. García-Gómez, J. V. Rovira |
| 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 ; 9, no. 1 ; Nr. 9, no. 1 (2012-01-04), S.57-70 |
| Datensatznummer |
250006651
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| Publikation (Nr.) |
 copernicus.org/bg-9-57-2012.pdf |
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| Zusammenfassung |
| Despite the particular management practices and climate characteristics of
the Mediterranean regions, the literature dealing with N budgets in large
catchments subjected to Mediterranean conditions is scarce. The present
study aims to deepen our knowledge on the N cycle within the Ebro River
Basin (NE Spain) by means of two different approaches: (1) calculating a
global N budget in the Ebro River Basin and (2) calculating a series of
detailed regional budgets at higher geographical resolution. N inputs and
outputs were spatialized by creating a map based on the most detailed
information available. Fluvial and atmospheric N export was estimated
together with N retention. The Ebro River Basin annually receives a
relatively high amount of new N (5118 kg N km−2 yr−1), mostly in the form of synthetic fertilizers (50%). Although
it is a highly productive catchment, the net N input as food and feed import
is also high (33%). Only 8% of this N is finally exported to the delta
zone. Several territorial units characterized by different predominant uses
(rainfed agriculture, irrigated agriculture and pastures) have
differentiated N dynamics. However, due to the high density of irrigation
channels and reservoirs that characterize Mediterranean catchments, N
retention is very high in all of them (median value, 91%). These results
indicate that problems of eutrophication due to N delivery in the coastal
area may not be too severe but that high N retention values may instead lead
to problems within the catchment, such as pollution of aquifers and rivers,
as well as high atmospheric emissions. The most promising management
measures are those devoted to reducing agricultural surpluses through a
better balanced N fertilization. |
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