The cation exchange capacity, sum of exchangeable bases, and saturation base degree of Ferralitic soils from the Republic
of Angola, determined by the Mehlich and ammonium acetate methods, were compared to update their taxonomy;
also, the exchangeable acidity was determined for deeper insight in their classification. Fourty eight representative
pedons of subordens of those soils (Tipoferralic, Weakly Ferralic and Psamoferralic) were analysed. Values of sum
bases and exchangeable Ca2+ and Mg2+ by the two methods were strongly correlated; cation exchange capacity, base
saturation degree and exchangeable K+ showed weaker and variable correlations, according to soil type. Exchangeable
acidity largely corresponded to Al3+, but its content was mostly less than one cmolc kg-1; its percentage regarding the
effective cation exchange capacity was mostly higher than 60%. Study soils show in overall subsurface horizons with
the characteristics of a ferralic horizon; therefore, they are mostly Ferralsols, which can be separated at first level in geric,
vetic e haplic Ferralsols, according to the effective cation exchange capacity value; also, at second level they are largely
dystric and, in great proportion, alumic. The weakness of study soils regarding the low nutrient retention capacity can
be alleviated by organic matter additions and limin
