Cation‐exchange Capacity of Clay‐rich Soils in Relation to Organic Matter, Mineral Composition, and Surface Area

Abstract

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.

Using support vector machines to predict cation exchange capacity of different soil horizons in Qingdao City, China

“…This suggests that silt and SOM particles contribute to CEC to a lesser extent than clay in this study area. This result is consistent with the findings of Martel et al (1978). Furthermore, the correlations between CEC and soil physicochemical properties are quite different among A and B horizons.…”

Estimation of exchangeable bases and base saturation from soil physical and chemical data

“…These results were consistent with data published by Martel et al(10) who also found SUMBAS to be significantly related to total clay content. The large regression coefficients for CLAY in…”

Clay mineralogy, cation exchange capacity and specific surface area of loess soils with different volcanic ash contents

“…The association between CEC and SSA was rather poor (R 2 = 0.175, p b 0.05, n = 24). Topsoil clay was associated with larger amounts of organic matter and this might be the reason for this poor correlation since SSA was measured on peroxidized samples (Martel et al, 1978).…”

“…Goldberg et al (1988) found that in soils of arid regions of California both SSA and the CEC were directly related to the stability of soil aggregates and clay dispersion. It is also known that the cation adsorption increases with increasing contents of fine particles, with the amount of 2 : 1 minerals (Martel et al, 1978), and the contents of soil organic matter (Thompson et al, 1989). Curtin and Smillie (1976) found that both organic matter and fine clay was significantly correlated with CEC in Irish soils from a wide range of parent materials.…”