Application of selective dissolution techniques to the study of non-crystalline components in a sequence of soils developed from granite in Sierra de Ancares (Galicia)
1986
Garcia-Rodeja, E. | Macias Vazquez, F. (Santiago Univ. (Spain). Facultad de Biologia)
The results obtained with several selective dissolution methods in the soils of a sequence on granite show the usefulness of these techniques to estimate the content and nature of poorly ordered components. In the studied soils, the nature of these components depends on the characteristics of parent material (fresh or weathered rock), the position of the soil in the slope and the type of horizon. Alumino-silicates with short range of oxiles (allophane and/or imogolite) and poorly crystalline aluminium hydroxides are abundant in horizons with low organic matter content of soils developed from weathered granite in steep slopes, that present good drainage and rapid and intense lateral movement of water. Al-humus complexes are important in A horizons of these soils and, especially, in superficial horizons of soils developed from alluvio-colluvial materials in the valley floor. In weakly evolved soils, formed on fresh rock, crystalline minerals are dominant in colloidal fractions
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