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Ionic strength of soil solution and its effect on charge properties of some New Zealand soils
Author(s) -
BLACK A. S.,
CAMPBELL A. S.
Publication year - 1982
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.1365-2389.1982.tb01763.x
Subject(s) - ionic strength , allophane , soil water , chemistry , ionic potential , aluminosilicate , soil organic matter , soil science , mineralogy , ion , ionic bonding , geology , aqueous solution , biochemistry , catalysis , organic chemistry
Summary Selected horizons from six New Zealand soils under permanent natural vegetation, four of which form a development sequence, were chosen to provide variations in organic matter, phyllosilicate clay mineral and short‐range ordered aluminosilicate (allophane) contents. The ionic strength of the soil solution (μ) extracted from the soils of the development sequence was low, being always less than 0.005. For all horizons of the six soils, the negative charge changes linearly with μ 1/2 within the ionic strength range of 0.001 to 1. The change was negligible for the least weathered and leached soil, indicating that it contained mainly permanently charged colloids. As soil development increased and/or the components carrying variable charge increased in amount, the change in charge with ionic strength increased. A regression equation showed a strong relationship between change in negative charge with ionic strength and organic carbon and oxalate‐extractable A1 ( R 2 =0.976). This equation was tested by predicting observed changes in charge with ionic strength for a second selection of soils. The change in positive charge with ionic strength was correlated with oxalate‐extractable A1 ( r 2 =0.914). The results are discussed in relation to measurement of soil charge and iron movement in soils.