​Volcanic ash soils formed from the weathering of materials ejected during volcanic eruptions. They are found in regions with intense volcanic activity such as the Pacific Ring of Fire. Approximately 60% of the soils in tropical countries are volcanic ash soils (Quantin, 1986; Shoji et al., 1993).  Volcanic eruptions have occurred during the last 20,000 years in the Andes Range in Colombia (Pleistocene and Holocene – Quaternary period). The location of major volcanoes and the correlated distribution of volcanic ash soils are shown in Figure 1. In the central region, they coincide with the Coffee Zone and the departments of Antioquia, Caldas, Risaralda and Quindio. In the southwestern region, they are found in the departments of Tolima, Huila, Cauca, Valle del Cauca and Nariño. And in the eastern areas, volcanic ash soils are distributed in a random pattern (Bogota and Llanos Orientales). These deposits play an important role in agriculture, especially for upland crop production.