The organic P composition of Vertisols as determined by 31P NMR spectroscopy

Title
The organic P composition of Vertisols as determined by 31P NMR spectroscopy
Publication Date
2014
Author(s)
McLaren, Timothy
Smernik, Ronald J
Guppy, Christopher
( author )
OrcID: https://orcid.org/0000-0001-7274-607X
Email: cguppy@une.edu.au
UNE Id une-id:cguppy
Bell, Mike J
Tighe, Matthew
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Soil Science Society of America
Place of publication
United States of America
DOI
10.2136/sssaj2014.04.0139
UNE publication id
une:17992
Abstract
Solution 31P nuclear magnetic resonance (NMR) spectroscopy on sodium hydroxide-ethylenediaminetetraacetic acid (NaOH-EDTA) extracts can provide detailed characterization of soil organic P, but has not been previously applied widely to Vertisols. Vertisol soils were collected at two depths (0-10 cm and 10-30 cm) for chemical and spectroscopic analysis. Sodium hydroxide-EDTA extracted a relatively consistent proportion (17 to 37%; average 25%) of the total organic P content determined by the ignition-H2SO4 extraction technique. Orthophosphate monoesters were the dominant form of organic P detected by solution 31P NMR spectroscopy of the NaOH-EDTA extracts, the majority of which appeared to be present in large 'humic' molecules, based on the predominance of a broad peak in the NMR spectra; some smaller signals due to glycerophosphate, inositol phosphates, and RNA-derived mononucleotides were also evident. The composition of organic P in the topsoil layer was very similar to that in the subsoil layer. Strong correlations were found between soil organic carbon (C) and nitrogen (N) and extractable organic P, which suggests that processes regulating the cycling of organic C and N are closely related to that for organic P in these Vertisols.
Link
Citation
Soil Science Society of America Journal, 78(6), p. 1893-1902
ISSN
1435-0661
0361-5995
Start page
1893
End page
1902

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