A LITTLE COMMENT to the Commentary about Soils, Paleosols and Geosols by Vance Holliday

Posted by A.Bronger 15 Jun 1999 13:49:02

Geographisches Institut der Universität Kiel, D-24098 Kiel, Germany

All discussion remarks are most welcome in our PP - NLs, the more critical the better. However I propose to reflect a bit more the literature,
especially when summarized in our Newsletter : otherwise we have only statements. The term buried paleosol versus buried soil is not the
major problem. However, non - buried paleosols (relict soils) -- showing two or more sets of properties which are related to different
combinations of soil - forming factors (esp. different climates and with it vegetation) -- play e.g. an important role for a full and correct
understanding of landscape history, which is essential for a proper appreciation of many modern environmental problems (cf. NL-12, p. 7). An
example are the “Red Soils’’ (Aridic Rhodustalfs or Chromic Lixisols) in South India which were formed in an earlier period of much more moist
climate than the present. In the present distinct seasonal semi - arid conditions ( < 1000mm rainfall and very high evapotranspiration) earlier soil
- forming processes such as deep weathering and strong kaolinite formation have almost ceased; instead secondary carbonate is accumulating
in the saprolite (Cr) and lower parts of the Lixisol Bt horizons, and under arable agriculture soil erosion is becoming a severe problem. It is
widely accepted that soil erosion can be tolerated from a crop production viewpoint provided soil formation keeps pace with it to compensate
for the losses. However, in today semiarid India the soil development processes have changed and the rate of compensatory regeneration of
soil is in effect (almost) zero. The erosion there is consequently a permanent loss of the country’s most important natural resources, but it has
not been recognized as such because the soils were not identified as paleosols.

Our definition (abbreviated here) is e.g. included in the "Glossary of Soil Science Terms" edited by the Soil Science Society of America (1997,
137 pp.).

The geosol concept as a pedostratigraphic unit which I think is a challenge for us will hopefully be discussed during the PP - poster session
(Convenor : J. A. Catt) during the INQUA - Congress in Durban.