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| Titel |
Long-term monitoring of nitrate transport to drainage from three agricultural clayey till fields |
| VerfasserIn |
V. Ernstsen, P. Olsen, A. E. Rosenbom |
| 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 ; 19, no. 8 ; Nr. 19, no. 8 (2015-08-07), S.3475-3488 |
| Datensatznummer |
250120784
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| Publikation (Nr.) |
 copernicus.org/hess-19-3475-2015.pdf |
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| Zusammenfassung |
| The application of nitrogen (N) fertilisers to crops grown on tile-drained
fields is required to sustain most modern crop production, but it poses a
risk to the aquatic environment since tile drains facilitate rapid transport
pathways with no significant reduction in nitrate. To maintain the water
quality of the aquatic environment and the provision of food from highly
efficient agriculture in line with the EU's Water Framework Directive and
Nitrates Directive, field-scale knowledge is essential for introducing water
management actions on-field or off-field and producing an optimal
differentiated N-regulation in future. This study strives to provide such
knowledge by evaluating on 11 years of nitrate-N concentration measurements
in drainage from three subsurface-drained clayey till fields (1.3–2.3 ha)
representing approximately 71 % of the surface sediments in Denmark
dominated by clay. The fields differ in their inherent hydrogeological field
settings (e.g. soil-type, geology, climate, drainage and groundwater table) and
the agricultural management of the fields (e.g. crop type, type of N fertilisers
and agricultural practices). The evaluation revealed three types of clayey
till fields characterised by: (i) low net precipitation, high concentration
of nitrate-N, and short-term low intensity drainage at air temperatures
often below 5 °C; (ii) medium net precipitation, medium concentration
of nitrate-N, and short-term medium-intensity drainage at air temperatures
often above 5 °C; and (iii) high net precipitation, low concentration
of nitrate-N and long-term high intensity drainage at air temperatures above
5 °C. For each type, on-field water management actions, such as the
selection of crop types and introduction of catch crops, appeared relevant,
whereas off-field actions only seemed relevant for the latter two field
types given the temperature-dependent reduction potential of nitrate
off-field. This initial well-documented field-scale knowledge from fields
that are representative of large areas in Denmark is a first step towards
establishing a differentiated N-regulation for clayey till areas.
Additionally, it provides a unique starting point by identifying important
parameters for future mapping of catchment-scale variations in nitrate
concentrations and fluxes. |
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