A Simplified, Sequential, Phosphorus Fractionation Method

Title
A Simplified, Sequential, Phosphorus Fractionation Method
Publication Date
2000
Author(s)
Guppy, Christopher
( author )
OrcID: https://orcid.org/0000-0001-7274-607X
Email: cguppy@une.edu.au
UNE Id une-id:cguppy
Menzies, N W
Moody, P W
Compton, B L
Blamey, F P C
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Taylor & Francis Inc
Place of publication
United States of America
DOI
10.1080/00103620009370556
UNE publication id
une:19893
Abstract
Hedley et al. (1982) developed what has become the most widely used (and modified), phosphorus (P) fractionation technique. It consists of sequential extraction of increasingly less phytoavailable P pools. Extracts are centrifuged at up to 25000 g (RCF) and filtered to 0.45 μm to ensure that soil is not lost between extractions. In attempting to transfer this method to laboratories with limited facilities, it was considered that access to high-speed centrifuges, and the cost of frequent filtration may prevent adoption of this P fractionation technique. The modified method presented here was developed to simplify methodology, reduce cost, and therefore increase accessibility of P fractionation technology. It provides quantitative recovery of soil between extractions, using low speed centrifugation without filtration. This is achieved by increasing the ionic strength of dilute extracts, through the addition of NaCl, to flocculate clay particles. Addition of NaCl does not change the amount of P extracted. Flocculation with low speed centrifugation produced extracts comparable with those having undergone filtration (0.025 μm). A malachite green colorimetric method was adopted for inorganic P determination, as this simple manual method provides high sensitivity with negligible interference from other anions. This approach can also be used for total P following digestion, alternatively non-discriminatory methods, such as inductively coupled plasma atomic emission spectroscopy, may be employed.
Link
Citation
Communications in Soil Science and Plant Analysis, 31(11-14), p. 1981-1991
ISSN
1532-2416
0010-3624
Start page
1981
End page
1991

Files:

NameSizeformatDescriptionLink