Nitrogen fertility and humic matter of chilean andosols

The principal volcanic ash soils of Chile is evidently the “trumao” soil that covers the Central Valley from an area north of Chillan (36°30′S) to Puerto Montt (4l03l′S), and which is very similar to Japanese Andosols in its morphological, chemical and physical properties (19, 20). The different conides of Antuco, Chillan, Villarrica, Llaima, Osorno, and others in this part of the Cordillera indicate that the parent materials of the soils could have various origins, not only horizontally but also vertically. Moreover, glaciations have further complicated the composition of the parent materials of the soils (Langohr, R., personal communication). Even earthquakes have influences on the soils in some districts (21). Irrespective of the origin of soil parent materials, certain trends appear to exist in some chemical and physical properties of the soils from north to south (18), suggesting a difference in fertility and organic matter.