
%0 Journal Article
%A Rasiah, V. 
%A Aylmore, L. A. G. 
%T Sensitivity of selected water retention functions to compaction and inherent soil properties
%J Soil Research
%D 1998/03/17
%V 36
%N 2
%P 317-326
%K soil water, bulk density, texture.
%R https://doi.org/10.1071/S97056
%U https://www.publish.csiro.au/paper/S97056 
%X It is known that field-scale variations in subsurface hydraulic characteristics are influenced, to a large extent, by soil properties. Limited information, however, exists on the sensitivity of hydraulic functions to field-scale variations in soil properties. The sensitivity of 4 soil water retention functions, &thgr;(h), to variations in soil properties and changes in bulk density (&rho;) across and within soils along a 500-m transect has been assessed in this study. The &thgr;(h) functions compared are those of van Genuchten, Brooks and Corey, Campbell, and Gardner. Water retention characteristics for 7 soils, each packed to 2 relative &rho;, were established for each function. The coefficient of determination, R 2 , for the best fit of water retention ranged from 0&#183;79 to 0&#183; 98 for the Gardner and Campbell functions, from 0&#183; 92 to 0&#183;99 for the Brooks and Corey function, and from 0&#183;83 to 0&#183;99 for the van Genuchten function. Simple linear regression analysis indicated the nonlinear slope parameters of the 4 functions were more strongly correlated with soil properties. However, only the van Genuchten slope parameters were sensitive to changes in &rho;. No consistency existed between the sensitivity of the linear parameters of the 4 functions and soil properties, and none were sensitive to changes in &rho;. Except for the a parameter in the van Genuchten function, all the parameters in this function can be predicted with satisfactory confidence from soil properties and &rho;. The results indicate that, of the 4 functions assessed, the van Genuchten &thgr;(h) function is the most sensitive to field-scale variations in soil properties along a transect in a landscape unit and to changes in &rho;. 
