2. Localization and distribution

The soils that currently cover the regions surrounding the volcanoes of the Andes Mountains in Colombia have their origin in pyroclastic materials that emanated during the volcanic eruptions of the last 25,000 years [9]. These deposits correspond to residual soils formed from the physical and chemical alteration of volcanic ash. Worldwide, volcanic ash soils represent approximately 0.84% of soils and are located predominantly in tropical regions [10, 13, 17, 21].

The soils derived from volcanic ash in Colombia occupy about 11.6% of the national territory and are located in regions of significant demographic and economic growth. In the Colombian coffee zone, it is estimated that about 350,000 ha of soils grown with coffee correspond to Andisols. These soils extend from the Eje Cafetero (Departments of Antioquia, Caldas, Risaralda, and Quindío) in the center of the country, to the departments of Tolima, Cauca, and Nariño to its south west.
