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Developing a reliable strategy to infer the effective soil hydraulic properties from field evaporation experiments for agro-hydrological models

Zhang, K., Burns, I. G., Greenwood, D. J., Hammond, J. P. and White, P. J. (2010) Developing a reliable strategy to infer the effective soil hydraulic properties from field evaporation experiments for agro-hydrological models. Agricultural Water Management, 97 (3). pp. 399-409. ISSN 0378-3774

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To link to this item DOI: 10.1016/j.agwat.2009.10.011

Abstract/Summary

The Richards equation has been widely used for simulating soil water movement. However, the take-up of agro-hydrological models using the basic theory of soil water flow for optimizing irrigation, fertilizer and pesticide practices is still low. This is partly due to the difficulties in obtaining accurate values for soil hydraulic properties at a field scale. Here, we use an inverse technique to deduce the effective soil hydraulic properties, based on measuring the changes in the distribution of soil water with depth in a fallow field over a long period, subject to natural rainfall and evaporation using a robust micro Genetic Algorithm. A new optimized function was constructed from the soil water contents at different depths, and the soil water at field capacity. The deduced soil water retention curve was approximately parallel but higher than that derived from published pedo-tranfer functions for a given soil pressure head. The water contents calculated from the deduced soil hydraulic properties were in good agreement with the measured values. The reliability of the deduced soil hydraulic properties was tested in reproducing data measured from an independent experiment on the same soil cropped with leek. The calculation of root water uptake took account for both soil water potential and root density distribution. Results show that the predictions of soil water contents at various depths agree fairly well with the measurements, indicating that the inverse analysis is an effective and reliable approach to estimate soil hydraulic properties, and thus permits the simulation of soil water dynamics in both cropped and fallow soils in the field accurately. (C) 2009 Elsevier B.V. All rights reserved.

Item Type:Article
Refereed:Yes
Divisions:No Reading authors. Back catalogue items
Interdisciplinary centres and themes > Centre for Food Security
Faculty of Life Sciences > School of Agriculture, Policy and Development > Biodiversity, Crops and Agroecosystems Division > Crops Research Group
Interdisciplinary centres and themes > Soil Research Centre
ID Code:33886
Uncontrolled Keywords:Inverse analysis Soil hydraulic properties Genetic Algorithm (GA) Soil water dynamics Root water uptake
Publisher:Elsevier

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