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Aluminium release in relation to the determination of cation exchange capacity of some podzolized New Zealand soils
Author(s) -
LEE R.,
BACHE B. W.,
WILSON M. J.,
SHARP G. S.
Publication year - 1985
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1985.tb00328.x
Subject(s) - cation exchange capacity , vermiculite , chemistry , chlorite , aluminium , leaching (pedology) , soil water , clay minerals , sorption , ion exchange , illite , inorganic chemistry , mineralogy , environmental chemistry , geology , soil science , materials science , metallurgy , ion , adsorption , organic chemistry , paleontology , quartz
SUMMARY In upper mineral horizons, CEC by compulsive and isotopic exchange methods, using Ba 2+ as the saturating cation, gave higher values than the effective CEC at natural soil pH, and much higher values than CEC determined with m NH 4 OAc at pH 7. Cumulative Al release during leaching was considerably higher using Mg 2+ and Ba 2+ chlorides than K + and NH 4 + chlorides, and gave a different shape extraction curve. Basal spacing of the dominant dioctahedral vermiculite in the soil clays contracted from 14.5Å to 10.0–10.9 Å when saturated with NH 4 + and K + , restricting release of interlayer Al. Lower horizons, containing a large proportion of Al‐chlorite in the clay fraction, which did not contract with any of the cations, showed more normal exchange behaviour. On leaching, Al release was slightly greater with K + and NH 4 + , than with Mg 2+ and Ba 2+ , chlorides. The implication of the results for CEC measurements is discussed.