Incremental acidification reveals phosphorus release dynamics in alkaline vertic soils

Title
Incremental acidification reveals phosphorus release dynamics in alkaline vertic soils
Publication Date
2015
Author(s)
Andersson, Karl
Tighe, Matthew
Guppy, Christopher
( author )
OrcID: https://orcid.org/0000-0001-7274-607X
Email: cguppy@une.edu.au
UNE Id une-id:cguppy
Milham, Paul
McLaren, Timothy
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier BV
Place of publication
Netherlands
DOI
10.1016/j.geoderma.2015.05.001
UNE publication id
une:18308
Abstract
Phosphorus (P) available to plants in alkaline, vertic soils is thought to be buffered by the dissolution of various calcium phosphate minerals (CaP), driven by pH and the concentration of Ca and/or P in solution. To investigate this hypothesis we incrementally acidified 6 alkaline vertic soils of CaP 300-6000 mg kg⁻¹ in the presence or absence of an anion exchange P sink. Following the early removal of solution and sorbed P sources, P recovery remained low until soil pH passed key thresholds. These thresholds varied little between soils and with the sink (pH 6.0-6.3), and soil pH buffer capacity affected the amount of acid required to approach the thresholds. Dissolution of CaP species occurred 0.7-1.0 pH units higher where the solution P concentration was kept below 1 μM using the anion exchange membrane sink compared to acidification without the sink. The data support the hypothesis that rhizosphere acidification may increase the availability of CaP minerals to plants; however, the dependence of P release dynamics on pH buffering capacity may put P release beyond the reach of some plant species. Consequently, research is necessary to quantify both plant acidification potential in these soils and the effect of concomitant removal of Ca on release of CaP species into plant available forms.
Link
Citation
Geoderma, v.259-260, p. 35-44
ISSN
1872-6259
0016-7061
Start page
35
End page
44

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