
TY  - JOUR
A1  - Smettem, K. R. J. 
A1  - Bristow, K. L. 
A1  - Heng, L. K. 
A1  - Oliver, Y. M. 
A1  - Ford, E. J. 
T1  - Obtaining soil hydraulic properties for water balance and leaching models from survey data. 1. Water retention
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 1999
VL  - 50
IS  - 2
SP  - 283
EP  - 289
KW  - 
UR  - https://doi.org/10.1071/A97074 
N2  - 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. 
ER  -

