| Autor: |
K. C. Abbaspour, Thomas Kätterer, R. Schulin, B. Schmied |
| Rok vydání: |
2001 |
| Předmět: |
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| Zdroj: |
European Journal of Soil Science. 52:25-36 |
| ISSN: |
1351-0754 |
| Popis: |
Summary We investigated the effect of initial moisture contents and mode of application on the displacement of multiple conservative tracers through undisturbed columns of a Humic Gleysol. Bromide was applied at the soil surface and chloride was injected at 5 cm depth. The columns were irrigated with deuterium-enriched water. A dual-porosity model and two single-porosity models were calibrated separately to Br– and Cl– elution curves in the two columns. Elution curves were almost identical for Br– and Cl– under initially wet conditions, whereas the displacement of Br– was faster than that of Cl– in the initially dry column, indicating rapid transport with preferential flow. Only the dual-porosity model described the long-tailing breakthrough of Cl– in the initially dry column adequately. The parameter values giving acceptable fits for ‘Br dry’ were not compatible with the description of the three other elution curves, which could be adequately modelled with a single set of parameter values. The estimated set of common parameters was validated by comparing with the elution curves of deuterium water, nitrate and sulphate, as well as with resident tracer concentrations at four depths. The results showed that solutes can be displaced much faster when applied at the surface of initially dry soil than when applied to wet soil or when resident in the soil matrix. The simulation results suggest that solute transport under initially dry conditions was governed by preferential flow of infiltration water through macropores by-passing the matrix due to shrinkage cracks and water repellence of matrix surfaces. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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