Authors / CoAuthors
Mann, A. | de Caritat, P. | Prince, P.
Abstract
The National Geochemical Survey of Australia (NGSA) was initiated in late 2006, and details of progress were published, among others, in Caritat et al. (2009). The ultra-low density geochemical survey was facilitated by, and based on, overbank sediment sampling at strategic locations in 1186 catchments. Included in the analysis methods was a partial extraction method by the Mobile Metal Ion (MMI) technique (Mann, 2010) of sediment sampled at the depth of 0-10 cm, air-dried and sieved to <2 mm. The MMI method is based on solubilisation of adsorbed ions and potentially can provide a measure of bio-availability, as ions in natural soil pore waters are subject to solubility by solutions stronger in complexing ability than pure water, but not subject to soil phase dissolution as achieved by strong acid or total digestion methods. Of the ten elements considered essential for plant growth (Ca, Cu, Fe, K, Mg, Mn, N, P, S and Zn), only two (N and S) were not included in the 53 elements analysed after MMI extraction of the overbank samples. Comparison of a number of MMI concentrations for each element with the corresponding total analysis for the same soil samples provides an estimate of the recovery % by MMI in a similar manner to that used by Albanese (2008) to evaluate ammonium acetate-EDTA as a measure of bio-availability. Individual maps for the eight nutrients based on MMI analysis provide some very interesting and potentially useful information. For example, highest 'bio-available' Fe concentrations are not related to the Fe-rich soils and rocks of the Pilbara, but to high rainfall areas close to the coast, where processes akin to lateritisation are still taking place. The movement of Fe as Fe2+ and its subsequent oxidation to Fe3+ is not only important to agriculture, but on the east coast of Australia it has a number of environmental consequences in river systems. The distribution pattern for Mn .../...
Product Type
nonGeographicDataset
eCat Id
71638
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
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2601
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Keywords
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- External Publication
- ( Theme )
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- regolith
- ( Theme )
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- geochemistry
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- AU
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2011-01-01T00:00:00
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geoscientificInformation
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[-44.0, -10.0, 112.0, 154.0]
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