University of Tasmania
Browse

File(s) under permanent embargo

Evaluation of rapid approaches for determining the soil water retention function and saturated hydraulic conductivity in a hydrologically complex soil

journal contribution
posted on 2023-05-17, 14:08 authored by Marcus HardieMarcus Hardie, Lisson, S, Richard DoyleRichard Doyle, Cotching, W
Knowledge of the soil water characteristic (SWC) and saturated hydraulic conductivity (Ksat) are required for simulation of soil water movement in most Richards’ equation based soil-water models. This study compared van Genuchten (VG) parameter values and Ksat determined by desorption with two rapid approaches, evaporative flux from intact cores, and inverse solution of tension infiltration data. Estimated and measured Ksat varied up to four orders of magnitude depending on parameterisation approach and antecedent soil moisture content. The SWC differed markedly between the laboratory drying and in situ wetting approaches due to the effects of hysteresis, air entrapment, clay swelling and water repellence. The evaporative flux approach was subjected to errors associated with prior saturation of the soil core, lack of K(ψ) data near saturation, and extrapolation of values beyond the measurement range of the upper tensiometer. Inverse solution of cumulative infiltration data from tension infiltrometers was able to discern the effects of antecedent soil moisture on soil structure and water repellence, however the approach had difficulty in obtaining unique local minima when the residual soil water content (θr) was included in the objective function. Both the evaporative flux and inverse solution of tension infiltration data approaches were improved by independent determination of the θr. Researchers should be aware that initial moisture content and methodology may influence VG parameter values, and that laboratory analysis of intact cores may result in Ksat and VG values which do not represent the hydraulic behaviour of field soils.

History

Publication title

Soil and Tillage Research

Volume

130

Pagination

99-108

ISSN

0167-1987

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Elsevier Science Bv

Place of publication

Po Box 211, Amsterdam, Netherlands, 1000 Ae

Rights statement

Copyright 2013 Elsevier B.V.

Repository Status

  • Restricted

Socio-economic Objectives

Soils

Usage metrics

    University Of Tasmania

    Categories

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC