Cation ratio of soil structural stability (CROSS)

Rengasamy, Pichu and Marchuk, Alla (2011) Cation ratio of soil structural stability (CROSS). Soil Research, 49 (3). pp. 280-285. ISSN 1838-675X

Abstract

Sodium salts tend to dominate salt-affected soils and groundwater in Australia; therefore, sodium adsorption ratio (SAR) is used to parameterise soil sodicity and the effects of sodium on soil structure. However, some natural soils in Australia, and others irrigated with recycled water, have elevated concentrations of potassium and/or magnesium. Therefore, there is a need to derive and define a new ratio including these cations in place of SAR, which will indicate the dispersive effects of Na and K on clay dispersion, and Ca and Mg on flocculation. Based on the differential dispersive effects Na and K and the differential flocculation powers of Ca and Mg, we propose the concept of 'cation ratio of soil structural stability' (CROSS), analogous to SAR. This paper also gives the results of a preliminary experiment conducted on three soils varying in soil texture on hydraulic conductivity using percolating waters containing different proportions of the cations Ca, Mg, K, and Na. The relative changes in hydraulic conductivity of these soils, compared with the control treatment using CaCl2 solution, was highly correlated with CROSS. Clay dispersion in 29 soils treated with irrigation waters of varying cationic composition was highly correlated with CROSS rather than SAR. It was also found that CROSS measured in 1:5 soil/water extracts was strongly related to the ratio of exchangeable cations. These results encourage further study to investigate the use of CROSS as an index of soil structural stability in soils with different electrolytes, organic matter, mineralogy, and pH.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2011 CSIRO. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 02 Sep 2014 01:21
Last Modified: 09 Feb 2017 05:17
Uncontrolled Keywords: exchangeable magnesium; exchangeable potassium; irrigation; sodicity; soil structure
Fields of Research : 05 Environmental Sciences > 0503 Soil Sciences > 050304 Soil Chemistry (excl. Carbon Sequestration Science)
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
09 Engineering > 0905 Civil Engineering > 090509 Water Resources Engineering
Socio-Economic Objective: D Environment > 96 Environment > 9614 Soils > 961499 Soils not elsewhere classified
Identification Number or DOI: 10.1071/SR10105
URI: http://eprints.usq.edu.au/id/eprint/25892

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