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A dual‐porous, inverse model of water retention to study biological and hydrological interactions in soil
Author(s) -
Laudone G. M.,
Matthews G. P.,
Gregory A. S.,
Bird N. R. A.,
Whalley W. R.
Publication year - 2013
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12055
Subject(s) - microporous material , porosity , hydraulic conductivity , soil structure , soil science , soil water , macropore , percolation (cognitive psychology) , water retention , porous medium , materials science , environmental science , chemistry , composite material , mesoporous material , biochemistry , neuroscience , biology , catalysis
Summary 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 W arren soil from R othamsted R esearch's W oburn E xperimental F arm in B edfordshire, 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 W arren 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.