Influence of antecedent soil moisture on hydraulic conductivity in a series of texture‐contrast soils |
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Authors: | Marcus A Hardie Richard B Doyle William E Cotching Kathrin Mattern Shaun Lisson |
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Institution: | 1. Tasmanian Institute of Agricultural Research, University of Tasmania, , Hobart, Tasmania, 7001 Australia;2. School of Agricultural Science, University of Tasmania, , Hobart, Tasmania, 7001 Australia;3. Secondment from Department of Primary Industries, Parks Water and Environment (DPIPWE), , Hobart, Australia;4. CSIRO Sustainable Ecosystems University of Tasmania, , Hobart, Tasmania, 7001 Australia;5. Tasmanian Institute of Agricultural Research, University of Tasmania, , Burnie, Tasmania, 7320 Australia |
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Abstract: | Antecedent soil moisture significantly influenced the hydraulic conductivity of the A1, A2e and B21 horizons in a series of strong texture‐contrast soils. Tension infiltration at six supply potentials demonstrated that in the A1 horizon, hydraulic conductivity was significantly lower in the ‘wet’ treatment than in the ‘dry’ treatment. However in the A2e horizon, micropore and mesopore hydraulic conductivity was lower in the ‘dry’ treatment than the ‘wet’ treatment, which was attributed to the precipitation of soluble amorphous silica. In the B21 horizon, desiccation of vertic clays resulted in the formation of shrinkage cracks which significantly increased near‐saturated hydraulic conductivity and prevented the development of subsurface lateral flow in the ‘dry’ treatment. In the ‘wet’ treatment, the difference between the hydraulic conductivity of the A1 and B21 horizons was reduced; however, lateral flow still occurred in the A1 horizon due to difficulty displacing existing soil water further down the soil profile. Results demonstrate the need to account for temporal variation in soil porosity and hydraulic conductivity in soil‐water model conceptualisation and parameterisation. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | duplex soil subsurface lateral flow soil‐water model water repellent vertic preferential flow |
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