9. Conclusions

The high humidity retention or high levels of saturation at the different tensions were confirmed as fundamental detonators of the mass removal of the studied soils, as a consequence of the instability of soil aggregates to water, high porosity, and high hydraulic conductivity and their relation with the mineralogy of these soils of volcanic origin, the high rainfall regimes of the region, the altitudinal position, slopes or inclination of the terrain that condition a high relative threat by mass movements.

Inter-variable correlations were found that facilitate explaining the phenomenon of mass removal in the area, among them some of significant order referring to the association between the variable "Humidity-Threat" and the organic matter for all the coverages analyzed. There is a negative effect of intervention on forests on the stability of soil aggregates.

There is a significant and positive relationship between the stability of the soil structure with the OM content and the degree of soil cover.

It is possible to explain the variations in the stability of aggregates, by the combined action of OM content and the degree of soil cover; however, this last variable is the most significant of the two.

The management of soils against mass removal should consult systems that involve minimal disturbance of the soil and the greatest possible protection through forest coverings, as ways to promote a stable structure and, consequently, promote the resistance of soils to water erosion.
