Soil: acidification cation exchange capacities

The acidity of the soil may conveniently be characterized by the content of metal ions, relative to the total cation exchange capacity of the soil. In the acid types of soil considered here, this base saturation degree is usually below 10%. The degree of base saturation will be reduced when (1) the roots take up exchangeable cations from the soil, and (2) when accumulation of dead plant material increases the amount of humus, and thereby the cation exchange capacity. To a certain degree, both of these processes are reversible, but if plant products are removed from the area without application of fertilizers, manure or lime, this represents an acidification by reducing the available supply of cations. 

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