Dilute Acid Extraction is a useful Indicator of the Supply of Slowly Available Phosphorus in Vertisols

Title
Dilute Acid Extraction is a useful Indicator of the Supply of Slowly Available Phosphorus in Vertisols
Publication Date
2014
Author(s)
McLaren, Timothy
Guppy, Christopher
( author )
OrcID: https://orcid.org/0000-0001-7274-607X
Email: cguppy@une.edu.au
UNE Id une-id:cguppy
Tighe, Matthew
Moody, Phil
Bell, Mike
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/sssaj2013.05.0188
UNE publication id
une:17108
Abstract
Long-term studies suggest readily available P, measured using a bicarbonate extractant, can be replenished by slowly available inorganic P pools. The aim of this study was to estimate the supply of slowly available P to the soil solution. Readily and slowly available P pools were measured using two agronomic soil P tests (the bicarbonate (Colwell) and dilute acid (Bureau of Sugar Experiment Stations; BSES) extractants, respectively) in vertisol soils of the northern grains region (NGR) of eastern Australia. The amount of P supplied to the soil solution was estimated by the iron oxide sink method accumulated over 96 h (FeOt-P). The readily available P pool (i.e., Colwell-P) was strongly correlated with FeOt-P, and this pool was likely to be replenished by the slowly available P pool (i.e., BSES-P) when BSES-P concentrations were >61 mg P kg⁻¹. The slowly available P pool did not supply the readily available P pool when the Ca (mg kg⁻¹)/P (mg kg⁻¹) ratio in the BSES extract was >74:1, suggesting the presence of Ca phosphates of low solubility affected potential buffering. Using a multiple linear regression, approximately 75% of the variability in the ability of the slowly available P pool to supply soil solution P could be explained by the quantity of BSES-P and the ratio of Ca/P in the BSES extract.
Link
Citation
Soil Science Society of America Journal, 78(1), p. 139-146
ISSN
1435-0661
0361-5995
Start page
139
End page
146

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