Zhang, Kefeng, Burns, Ian G., Greenwood, Duncan J. , Hammond, John P. and White, Philip J. (2010) Developing a reliable strategy to infer the effective soil hydraulic properties from field evaporation experiments for agro-hydrological models. Agricultural Water Management, Vol.97 (No.3). pp. 399-409. doi:10.1016/j.agwat.2009.10.011 ISSN 0378-3774.

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Abstract

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.

Item Type:	Journal Article
Subjects:	S Agriculture > SB Plant culture
Divisions:	Faculty of Science, Engineering and Medicine > Science > Life Sciences (2010- ) > Warwick HRI (2004-2010)
Library of Congress Subject Headings (LCSH):	Soils, Irrigated -- Research, Plant-water relationships -- Research, Inversion (Geophysics), Genetic algorithms -- Research, Roots (Botany) -- Ecology
Journal or Publication Title:	Agricultural Water Management
Publisher:	Elsevier BV
ISSN:	0378-3774
Official Date:	March 2010
Dates:	Date Event March 2010 Published
Volume:	Vol.97
Number:	No.3
Page Range:	pp. 399-409
DOI:	10.1016/j.agwat.2009.10.011
Status:	Peer Reviewed
Access rights to Published version:	Open Access (Creative Commons)
Funder:	Great Britain. Dept. for Environment, Food & Rural Affairs (DEFRA)
Grant number:	HH3507SFV (DEFRA), HH3509SFV (DEFRA)

Data sourced from Thomson Reuters' Web of Knowledge

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