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Cation‐exchange Capacity of Clay‐rich Soils in Relation to Organic Matter, Mineral Composition, and Surface Area
Author(s) -
Martel Y. A.,
De Kimpe C. R.,
Laverdière M. R.
Publication year - 1978
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1978.03615995004200050023x
Subject(s) - cation exchange capacity , organic matter , clay minerals , soil water , illite , vermiculite , mineralogy , chemistry , composition (language) , chlorite , geology , environmental chemistry , soil science , quartz , paleontology , linguistics , philosophy , organic chemistry
Regression analyses were used to correlate organic matter, texture and surface area values to the cation‐exchange capacity (CEC) of clay‐rich soils in the lowlands of Quebec. The Ap, Bg and Cg horizons of 11 Gleysolic soils (Aqu‐Suborders) were analyzed for CEC, exchangeable bases and acidity, total and fine clay contents, organic matter, surface area and mineralogical composition. The soils contained illite, chlorite, smectite, and vermiculite in addition to quartz and feldspars. In the Ap horizon, total clay ( r = 0.815**) and fine clay ( r = 0.841**) contents were better related to CEC than organic matter ( r = 0.566**) and surface area ( r = 0.570**). In the Bg and Cg horizons, surface area ( r = 0.918** and 0.814**) gave the best correlation with CEC. As calculated by multiple regression equations, CEC values of organic matter increased with depth from 56.5 to 223 meq/100 g, while CEC values of total clay decreased from 37.7 to 22.5 meq/100 g and that of fine clay decreased from 57.5 to 50.7 meq/100 g. Variations in the mineralogical composition, although small, were sufficient to explain nearly 50% of the variations in the CEC. Clay mineralogy is important to predict the CEC of such soils where the contribution of clay is 3.5 to 5 times greater than that of organic matter.