Abstract
The influence of the clay and the organic matter upon the value of cationic exchange capacity in the northern soils of Algeria was investigated. Data of 848 out of 279 representative profiles of northern soils of Algeria have been extracted from pedological data bank, Results have shown that the organic matter has no significant effect on the cationic exchange capacity which depends mainly on the clay fraction. The clayish behavior of studied soils in regard to their cationic exchange capacity is situated between the illite and smectite pools with a general tendency toward a bebavior of an interstratified illite/smectite type.