Hello,

concerning Ultisol and Oxisol (Acrisols and Ferralsols in WRB), as commonly they are "old" soil resulting from intense leaching of base cations and eluviation of clay  along long period of landscape stabibility, you cannot generalize their origin. They have common actual "features" (low CEC, argilic or ferralic horizon) but concerning their genesis they can have polylithologic origin resulting of weathering of different parent material. They seems to be linked to humid climate according to soil scientist, nevertheless you should also take into account more geodynamic factors allowing intense wetahering like lithospheric upwarping (see Works of Robert Wyns).

Este documento puede ayudar:

Atlas de suelos de América Latina y el Caribe (en castellano)

http://eusoils.jrc.ec.europa.eu/library/maps/LatinAmerica_Atlas/Documents/LAC.pdf

El atlas utiliza la taxonomía de la WRB, entonces busca Acrisols y Ferralsols.

No me gusta la US Soil Tax porque no le interesan los procesos. Tampoco es buena idea incluir el clima actual (que sólo es una fotografía instantánea) en un nivel alto en la taxonomía de suelos.

Hello,

concerning Ultisol and Oxisol (Acrisols and Ferralsols in WRB), as commonly they are "old" soil resulting from intense leaching of base cations and eluviation of clay  along long period of landscape stabibility, you cannot generalize their origin. They have common actual "features" (low CEC, argilic or ferralic horizon) but concerning their genesis they can have polylithologic origin resulting of weathering of different parent material. They seems to be linked to humid climate according to soil scientist, nevertheless you should also take into account more geodynamic factors allowing intense wetahering like lithospheric upwarping (see Works of Robert Wyns).

Hi Manuel:

Here a couple of books that they could help you:

- Soils: genesis and geomorphology (Schaetzl & Thompson, 2015).

- Soil genesis and Classification (Boul et al., 2011).

Kind regards,

Pablo

Hello there.

Thanks everyone for your answers!!!

I really appreciate that.

greetings from Costa Rica.

The important process in Ultisols would be desilication, accumulation of iron and aluminum oxides and low activity clay formation. Use the published literature from south America and Hawaii on similar soils and compare with your conditions.

The paper below may be useful for you

LEPSCH, I.F. & BUOL, S.W. Investigations in an oxisol-ultisol toposequence in São Paulo State, Brazil. Soil Sci. Soc. Am. Proc., 38:491-496, 1976.

Generally, Ultisols (from Latin ultimus, "last") are strongly leached, acid forest soils with relatively low native fertility. They are intensely weathered soils of warm and humid climates. Ultisols are normally formed on older geologic locations in parent material that is already extensively weathered. They are found primarily in humid temperate and tropical areas of the world, typically on older, stable landscapes. Intense weathering of primary minerals and leaching of cations including Ca, Mg, and K have occurred in these soils. There has been accumulation of clay minerals in the B horizon.

I think if you consult the book by Brady and Weil "The nature and properties of soils”, you may may get the required information.

I hope this paper help you!

Hello there

Thank so much for your time and answers!!!

Best regards!!!

I would request you to refer to the following two papers. One is  a research paper on Ultisols of Kerala, Southern India and other is a  review paper on this subject; which  is a state of the art information. I think you may find these two publication informative.