SOIL DEVELOPMENT INDICES OF SOILS DEVELOPED ON FLUVIAL TERRACES (PEÑARANDA DE BRACAMONTE, SALAMANCA, SPAIN).

ALONSO,P.1; SIERRA, C.2; ORTEGA, E.2; DORRONSORO, C.1
1. Departamento de Edafología y Química Agrícola, Facultad de Farmacia, Universidad de Salamanca.
2. Departamento de Edafología y Química Agrícola, Facultad de Farmacia, Universidad de Granada.

ABSTRACT

The relationship between age of fluvial terrace soils with morphological and chemical indices and the depth of the horizons indicates two main trends: i) as soil age increases index values tend to increase throughout the chronosequence; ii) degree of differentiation between the horizons of each soil becomes progressively more evident.
In the first phase (Holocene soils) the rate of soil formation is rapid. Afterwards, in soils of the Late Pleistocene age, the pace decreases. At the end of this phase (some 100,000 years) soil reaches a state of maturity. Finally in Middle Pleistocene soils (300,000 to 600,000 years old) evolution of these Palexeralfs is even slower. Morphological and analytical indices in all these soil undergo continuous changes throughout the chronosequence without seeming to reach a steady state.