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| Titel |
Calibration of a one-dimensional water flow model for the evaluation of the reclamation success of saline soil substrates |
| VerfasserIn |
Mandana Shaygan, Thomas Baumgartl, Sven Arnold, Lucy Reading, Andrew Fletcher |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102171
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| Publikation (Nr.) |
 EGU/EGU2015-1451.pdf |
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| Zusammenfassung |
| Highly saline-sodic soils restrict plant establishment. Salt affected soils may be reclaimed by
leaching salts from a potential root zone. Soil amendments can be used as a reclamation
technique to improve the soil pore system and hydraulic functions, which allows the
downward transport of water under certain precipitation conditions. The objective of this
study was to investigate salt movement within saline-sodic soil at a small scale in soil
columns and assess the success of amendment strategies for reclamation of the soil. For the
purpose of predicting the effect of typical rainfall scenarios on the reclamation of
saline-sodic soils, a one-dimensional numerical water flow model (HYDRUS-1D) was
tested and calibrated. The model was calibrated using data from laboratory column
experiments. A saline-sodic soil was packed into 30 cm long columns (diameter
7cm) from a depth of 10 to 30 cm and then covered with the same soil, however
amended with 40% (wt/wt) fine sand and 20% (wt/wt) wood chips, respectively. A
column filled with the saline-sodic soil only to a depth of 30 cm was used as a
control. The experiments were carried out by establishing an initial pressure head of
-60 cm at the soil surface. Based on climate data from a location in south-west
Queensland, rainfall scenarios with 50% and 1% probability of annual exceedance for this
location were calculated and applied to the soil columns. The hydrological response in
the columns was monitored by measuring the water potential using tensiometers
installed in three depths (3, 11 and 25 cm) and knowledge of inflow and outflow of the
columns. The simulation captured the observed trends in the results for the investigated
columns and measured depths under heavy rainfall events as well as surface substrates
exposed to small rainfall events, where the simulated and measured results were in
very good agreement, with R2 values generally ranging between 0.92 and 0.98.
The simulated results also provided a good description of the observed results for
the subsoils (25 cm) of the columns subjected to the land reclamation strategies
under small rainfall events (R2 ranged between 0.82 and 0.86). This study identified
that the model can be applied to simulate water flow in the soil profile subjected
to rehabilitation techniques as influenced by intensive water application/rainfall
patterns.
Key words: HYDRUS-1D, Model calibration, Rainfall event, Water flow |
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