ABSTRACT.
VARIATIONS OF SOME PROPERTIES OF A VOLCANIC ASH SOIL (VITRANDEPT) SUBJECTED TO INTENSIFIED LEACHING, UNDER LABORATORY CONDITIONS. I. EXCHANGEABLE COMPLEX

Walter Luzio L,1, Wilfredo Vera E.2, René Elissegaray C.3, y Mónica Menis M.4.
 

The variations of physical-chemical properties of a soil derived from volcanic ash and subjected to intensified leaching, under laboratory conditions, was studied. The leaching method proposed by Pedro (1964), with modifications, was used.
In order to get a very intensive hydrolysis, soil samples were placed in twelve soxhlets column systems. Every 45 days three soxhlets were analyzed. In addition, a check sample was analyzed at the begining of the experiment.
The tendencies of the processes were as follows: significant decreases of soluble and exchangeable cations, with a higher rate of loss for monovalent than bivalent cations. Decreases in CEC, base saturation, and organic matter, was also detected.
The electrical conductivity of the soils in the soxhlets also diminished, but increased in the leached solutions.
The tendency of the variations of soil properties was expressed by exponential equations, and quantified through definite integration.
According to the variations measured, it was possible to conclude, as a first approximation, that the soil underwent an evolution.

Keywords:
1Ing. Agr., M. S., Depto. Ingenieria y Suelos, Facultad de Agronomía, Universidad de Chile, Casilla 1004, Santiago.
2 y 3lngs. Agrs., Depto. Ingenieria y Suelos, Facultad de Agronomía, Universidad de Chile, Casilla 1004, Santiago.
4Ingeniero Agrónomo.