Suelos fersialíticos sobre cenizas volcánicas. I. Características morfológicas y físico-químicas

Abstract

The authors study the morphological and physico-chemical characteristics of fersialitic soils, developed on volcanic-phonolitic ash of Canary Islands. There are two groups of profiles. The first formed by young soils, rich in primary minerals. They show brown or red-brown hues, clayed textures and slightly developed structures. The other profiles are old soils, with red-brown or red hues, clayed textures with argillic horizon and very developed prismatics structures. The physico-chemical characteristics are relatively homogenous in all profiles. In each profile, these properties can show great differences between the horizons due tothe frequency of volcanic and colluvial materials with different chemical and mineralogical composition received by the soil at different stages. Barranco Hondo Alto and Las Mejoranas profiles show some characteristics that differ from the other soils, as pH, base saturation, total SiO2, etc. We can explain these differencias by the ecological conditions in the first case and the high degree of geochemical evolution in the second.