Modification of the McNeal clay swelling model improves prediction of saturated hydraulic conductivity as a function of applied water quality

Ezlit, Y. D. and Bennett, J. McL. and Raine, S. R. and Smith, R. J. (2013) Modification of the McNeal clay swelling model improves prediction of saturated hydraulic conductivity as a function of applied water quality. Soil Science Society of America Journal, 77 (6). pp. 2149-2156. ISSN 0361-5995

Abstract

A review of the McNeal clay swelling model, including its underpinning assumptions and the method for determining its parameters, was undertaken. Limitations of the model include model parameter identification, the fixed threshold exchangeable sodium percentage level at which hydraulic conductivity begins to decline, and the assumption that the expanding clay will always be 10% of the soil. To overcome these problems, an improved form of the model that accommodates a range of clay content is proposed. The modified model was used to estimate the reduction in saturated hydraulic conductivity in the three McNeal groups of soils containing different percentages of expanding clay. The model produced good agreement between the observed and estimated saturated hydraulic conductivities over the entire range of irrigation salinity (3–200 mmolc/L) and sodicity used for the original swelling model. The modified model was also successfully validated
against three new sets of relative hydraulic conductivity data. The generalization of interlayer clay swelling in the modified model is more appropriately described as determining the dispersive potential of a given solution, rather than physical interlayer swelling. Consequently, this modified model more accurately predicts the reduction in saturated hydraulic conductivity as a function of the sodicity and salinity of the applied water.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © Soil Science Society of America. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Publisher does not formally support archiving.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 19 Nov 2013 02:28
Last Modified: 03 Dec 2014 06:26
Uncontrolled Keywords: salinity; irrigation; clay soils; McNeal model
Fields of Research : 05 Environmental Sciences > 0502 Environmental Science and Management > 050209 Natural Resource Management
05 Environmental Sciences > 0503 Soil Sciences > 050305 Soil Physics
05 Environmental Sciences > 0503 Soil Sciences > 050302 Land Capability and Soil Degradation
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960905 Farmland, Arable Cropland and Permanent Cropland Water Management
D Environment > 96 Environment > 9614 Soils > 961402 Farmland, Arable Cropland and Permanent Cropland Soils
D Environment > 96 Environment > 9609 Land and Water Management > 960904 Farmland, Arable Cropland and Permanent Cropland Land Management
Identification Number or DOI: 10.2136/sssaj2013.03.0097
URI: http://eprints.usq.edu.au/id/eprint/24270

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