A dual-porous, inverse model of water retention to study biological and hydrological interactions in soil

A - Papers appearing in refereed journals

Laudone, G. M., Matthews, G. P., Gregory, A. S., Bird, N. R. A. and Whalley, W. R. 2013. A dual-porous, inverse model of water retention to study biological and hydrological interactions in soil. European Journal of Soil Science. 64 (3), pp. 345-356.

AuthorsLaudone, G. M., Matthews, G. P., Gregory, A. S., Bird, N. R. A. and Whalley, W. R.
Abstract

The deterministic modelling of bio-hydrological processes in soil requires a void structure model that is explicitly dual-porous containing fully and separately characterized macroporosity and microporosity. It should also contain information that relates the positioning of microporosity relative to macroporosity. An example of such a process is the production of nitrous oxide, in which bacteria in microporous hot-spots' are supplied with nutrients and gases through a macroporous pathway. We present a precision void-structure model that satisfies these two criteria, namely explicit macroporosity and microporosity, and their positional relationship. To demonstrate the construction of the model, we describe the modelling of a single soil, namely Warren soil from Rothamsted Research's Woburn Experimental Farm in Bedfordshire, UK, although the modelling approach is applicable to a wide range of soils and other dual porous solids. The model is capable of fitting several fundamental properties of soil, namely water retention, aggregate size distribution, and porosity of the microporous and macroporous zones. It comprises a dendritic critical percolation path, around which are clustered the microporous regions. The saturated hydraulic conductivity of the dual-porous network is of the correct order of magnitude for a soil of the same density and texture as the Warren sample. Finally, we demonstrate how the preferential flow pathway in the resulting structure differs from the critical percolation pathway, and that only 4.6% by volume of the unclogged macroporosity contributes to the fluid flow through the structure.

KeywordsSoil Science
Year of Publication2013
JournalEuropean Journal of Soil Science
Journal citation64 (3), pp. 345-356
Digital Object Identifier (DOI)doi:10.1111/ejss.12055
Open accessPublished as non-open access
Funder project or codeSEF
The Rothamsted Long-Term Experiments including Sample Archive and e-RA database [2012-2017]
Understanding soil quality and resilience: effects of perturbations and natural variations on nitrous oxide emission, water retention and structure (RRES)
FunderBiotechnology and Biological Sciences Research Council
Output statusPublished
Copyright licenseCC BY
ISSN13510754
PublisherWiley
Grant IDBB/E001793
BB/E001580

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