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Pedo‐transfer functions for estimating unsaturated hydraulic properties of Portuguese soils
Author(s) -
GONÇALVES M. C.,
PEREIRA L. S.,
LEIJ F. J.
Publication year - 1997
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.1997.tb00205.x
Subject(s) - hydraulic conductivity , soil water , pedotransfer function , water retention , soil science , water retention curve , bulk density , soil gradation , particle size distribution , environmental science , water content , particle size , geotechnical engineering , geology , paleontology
Summary The measurement of unsaturated soil hydraulic properties is expensive and time consuming. These properties are hence frequently predicted with so‐called pedo‐transfer functions (PTFs) using basic soil properties (e.g. particle‐size distribution, organic matter content and bulk density). In this study PTFs are developed by regression between hydraulic data and basic soil properties. Parameters are quantified for: (i) the retention model of van Genuchten using 80 soil profiles with a total of 230 retention curves, and (ii) the conductivity model of Gardner using 20 soil profiles and 129 hydraulic conductivity curves. The profiles represent the main soil families in Portugal, ranging from coarse sands to heavy clays. The PTFs derived from data for all soils provide a fairly poor description of the hydraulic parameters because of the heterogeneity of the profiles. The description of several parameters is improved by using PTFs that are developed for more homogeneous soils grouped according to their particle‐size distribution. A further improvement is achieved by including the water contents at 2·5 cm, 100 cm, and 15 000 cm water suctions in the retention PTFs, or the saturated hydraulic conductivities in the conductivity PTFs.