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Sodium and potassium in soils of the Murray–Darling Basin: a note

D. E. Smiles
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CSIRO Land and Water, PO Box 1666, Canberra, ACT 2601, Australia. Email:

Australian Journal of Soil Research 44(7) 727-730
Submitted: 2 May 2006  Accepted: 4 September 2006   Published: 20 October 2006


There is, on average, more water-soluble and exchangeable potassium than sodium across a range of soils in the Murray–Darling Basin. Because water-soluble sodium and potassium are roughly equivalent in terms of their effects on soil structural stability, this implies that, for these soils, potassium is probably as important as is sodium. Neglect of potassium and simple appeal to the sodium adsorption ratio and solution concentration to infer structural stability will thus be misleading.

Additional keywords: potassium, sodium, soil structure, stability.


Emeritus Professor N Collis-George, and Drs H. P. Cresswell, J. M. Kirby, and N. J. McKenzie of this Division offered helpful comments.


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