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Obtaining soil hydraulic properties for water balance and leaching models from survey data. 1. Water retention

Smettem, K.R.J., Oliver, Y.M., Heng, L.K., Bristow, K.L. and Ford, E.J. (1999) Obtaining soil hydraulic properties for water balance and leaching models from survey data. 1. Water retention. Australian Journal of Agricultural Research, 50 (2). pp. 283-289.

Link to Published Version: https://doi.org/10.1071/A97074
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Abstract

A physico-empirical 2-parameter power law model of the draining water retention curve (WRC) based solely on clay content is described and further developed using 6 datasets obtained from Australian and New Zealand soils. The slope of the WRC, or pore-size distribution index, is well described by the model but the bubbling pressure, or inflection point is poorly described. Without a good estimation of the bubbling pressure it is not possible to scale the physico-empirical model to the WRC. To achieve the scaling, a single measured point on the WRC in the unsaturated range is required. The resulting estimated water contents may be satisfactory for application within broad-scale leaching risk models and for generalised extrapolation of results from detailed experimental sites but caution is still required for quantitative applications of nitrate leaching models at a particular site.

It is concluded that soil surveys could usefully include a single WRC measurement in the field at each sampling location to improve their utility for water and chemical transport modelling.

Publication Type: Journal Article
Publisher: CSIRO
Copyright: © CSIRO 1999
URI: http://researchrepository.murdoch.edu.au/id/eprint/38135
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