Reduction of hydraulic conductivity and loss of organic carbon in non-dispersive soils of different clay mineralogy is related to magnesium induced disaggregation
Article
Article Title | Reduction of hydraulic conductivity and loss of organic carbon in non-dispersive soils of different clay mineralogy is related to magnesium induced |
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ERA Journal ID | 5257 |
Article Category | Article |
Authors | Zhu, Yingcan (Author), Bennett, John McLean (Author) and Marchuk, Alla (Author) |
Journal Title | Geoderma |
Journal Citation | 349, pp. 1-10 |
Number of Pages | 10 |
Year | 2019 |
Publisher | Elsevier |
Place of Publication | Netherlands |
ISSN | 0016-7061 |
1872-6259 | |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.geoderma.2019.04.019 |
Web Address (URL) | https://www.sciencedirect.com/science/article/pii/S0016706118321013 |
Abstract | Irrigation water containing appreciable amount of magnesium (Mg) is increasingly used in farming. However, studies on the effect of Mg on soil permeability and structural stability are limited and the results are contradicting. In this study, four soils of different dominant clay mineralogy, specifically kaolinite, illite and montmorillonite, were used to investigate the effect of Mg on saturated hydraulic conductivity (Ksat), interaction with organic carbon and soil clay dispersion and to compare to the effect of Ca. The soils were packed in columns and leached with four groups of either Ca-Ca, Ca-Mg, Mg-Mg or Mg-Ca solutions at the successive concentrations of 0.5, 0.25, 0.1, 0.05, 0.025, 0.01, 0.005, 0.001 and 0.0001 M, and finally with deionised water. Ksat was measured and leachates were assessed for dissolved organic carbon (DOC) and dispersion as turbidity. The leached soils were tested for aggregate stability, mechanical dispersion and zeta potential. This study showed that Mg had a disaggregation effect on soil structural stability. As compared to Ca, Ksat on Mg treated cores were lower over a wide range of concentrations, desorption of DOC and turbidity from Mg clay surface was higher, although the dispersion in leachates was insignificant under both Mg and Ca treatments. The effect of Mg treatment was more pronounced on smectic and illitic soils. The decrease in Ksat was related to Mg induced disaggregation, due to intra-crystalline swelling and/or the inter-crystalline swelling in Mg treated soil clays. |
Keywords | Magnesium; Calcium; Saturated hydraulic conductivity; Dissolved organic carbon; Turbidity |
ANZSRC Field of Research 2020 | 410604. Soil chemistry and soil carbon sequestration (excl. carbon sequestration science) |
410699. Soil sciences not elsewhere classified | |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Byline Affiliations | Centre for Sustainable Agricultural Systems |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q5qx1/reduction-of-hydraulic-conductivity-and-loss-of-organic-carbon-in-non-dispersive-soils-of-different-clay-mineralogy-is-related-to-magnesium-induced-disaggregation
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