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| Titel |
Analysing flow patterns in degraded peat soils using TiO2 dye |
| VerfasserIn |
Haojie Liu, Bernd Lennartz |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086536
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| Publikation (Nr.) |
 EGU/EGU2014-421.pdf |
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| Zusammenfassung |
| Dye tracing is a valuable method for studying the flow patterns in soils. However, limited
information is available on water flow and solute transport pathways in dark colored peat
soils because the frequently used Brilliant Blue FCF dye does not visibly stain the soil. In this
study, we were aiming at testing the suitability of Titanium dioxide (TiO2) as a dye tracer for
dark peat soils. The objectives were to quantify the physical properties of different
degraded peat soils and visualize the flow patterns. Soil samples were collected
from two low-lying fen sites, where the top soil was highly degraded, while lower
horizons were less decomposed. Dye tracer experiments were conducted at both
sites by applying a TiO2 suspension (10 g/l) with a pulse of 40 mm. Soil profiles
were prepared for photo documentation the following day. It was found that the
physical and hydraulic properties of peat were significantly influenced by the degree
of peat decomposition and degradation. Higher decomposed and degraded peat
soils had a higher bulk density, lower organic matter content and lower porosity.
Moreover, higher decomposition and degradation resulted in a lower saturated hydraulic
conductivity as long as investigated samples originated from the same site. In addition,
degraded peat soils showed less anisotropy than un-degraded peat. It turned out that
TiO2 is a suitable dye tracer to visualize the flow paths in peat soils. Although
dye patterns differed within the same plot and between different plots, most of the
flow patterns indicated a preferential flow situation. The distribution of TiO2 in the
soil profile, as analyzed from 5 by 5 cm grid cells, compared to the distribution of
bromide, which was applied along with the dye confirming the suitability of the dye
tracer. Un-decomposed plant structures, such as wood branches and leaves, were
identified as the major preferential flow path in un-degraded peat. For degraded peat,
bio-pores, such as root and earthworm channels operated as the major transport domain. |
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