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| Titel |
Dynamics of Phosphorus export from small forested catchments in low mountain
ranges in Germany |
| VerfasserIn |
Stefan Julich, Dorit Julich, Raphael Benning, Karl-Heinz Feger |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250148122
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| Publikation (Nr.) |
 EGU/EGU2017-12352.pdf |
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| Zusammenfassung |
| Phosphorus (P) plays an important role in the nutrition of forest ecosystem. The transport of P
in forest soils predominantly occurs along preferential water flow pathways bypassing large
parts of the soil matrix. Therefore, rapid flow processes by preferential flow and/or during
storm events may lead to significant P losses from forest soils. However only little knowledge
about the dynamics, magnitude and driving processes of P exports into surface water
exist.
In this contribution, we present the results of two studies where two small forested
catchments have been monitored for a period around 3 years. Both catchments are situated in
low mountain ranges in Saxony (catchment size 21 ha) and Thuringia (catchment size 5 ha)
representing medium P contents in the topsoil of 1142 mg kg−1 and 834 mg kg−1
respectively. During the regular sampling (monthly to weekly sampling frequency), the mean
Total-P concentrations of 23 μg L−1(Thuringian Site) and 8 μg L−1(Saxonian Site) have
been measured. However, during single storm events Total-P concentrations increased
considerably with maximum concentrations of 134 μg L−1(Thuringian Site) and 203 μg
L−1(Saxonian Site). Our findings indicate that during storm events, especially after longer
dry periods, significant amounts of phosphorus can be exported from forest ecosystems.
Comparison of discharge-concentration patterns of Total-P, Nitrogen and DOC, as well as dye
tracer experiments, suggest that preferential flow along biopores and stone surfaces, and the
interface between mineral soil and litter layer are main pathways of export from
forests.
For the site in Saxony we calculated mean annual export rates of 32.8 to 33.5 g ha−1 a−1
based on the weekly sampling with different load calculation methods (flow weighted
methods up to linear regression models). If the events are included into the annual load
calculation the mean annual export fluxes increase from 47.8 to 58.6 g ha−1 a−1 based on the
different load calculation methods. This implies that the estimation of P-exports from
forested catchments need to be based on appropriate monitoring schemes and load estimation
methods. |
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