Title

Soil Tests for Aluminum Toxicity in the Presence of Organic Matter: Laboratory Development and Assessment

Author Info

M. G. Whitten, University of Western Australia
G. S.P. Ritchie, University of Western AustraliaFollow

Recommended Citation

Postprint version. Published in Communications in Soil Science and Plant Analysis, Volume 22, Issue 3 & 4, February 1, 1991, pages 343-368.

NOTE: At the time of publication, the author G.S.P. Ritchie was not yet affiliated with Cal Poly.

The definitive version is available at https://doi.org/10.1080/00103629109368421.

Abstract

Al toxicity in plants is related to the activity of Al³⁺ and Al-hydroxy monomers in the soil solution, whereas Al complexed with ligands such as fluoride (F), sulphate (SO₄^2-), and oxalate is not toxic. Estimation of toxic Al relies on measurement of “labile”; Al after short contact times with colorimetric reagents or cation-exchange resins. However, shifts in equilibrium may result in non-toxic forms of Al reacting with the complexing agent or resin.

A series of laboratory experiments tested the degree to which labile Al is related to Al³⁺ in simplified media and compared methods of estimating labile Al in the presence of organic ligands and in soils. Cation-exchange resins extracted more than the theoretical concentration of Al³⁺ from solutions containing a range of concentrations of OH^- and SO₄^2-. More Al was extracted in 15 s by 8-hydroxy-quinoline than by Chelex-100 from solutions of Al-humate at pH 4. In sands which had been spiked with Al and organic matter, the estimation of labile Al varied with both the method of measurement and type of extract. The cations present in commonly used soil-extracting chloride solutions can decrease the proportion of organically complexed Al.

Disciplines

Food Science | Nutrition

Copyright

1991 Taylor & Francis.

Publisher statement

This is an electronic version of an article published in Communications in Soil Science and Plant Analysis.