Two routes in genesis of strongly differentiated acid soils under humid, cool-temperate conditions

When usual pedological data are combined with detailed biogeochemical and crystallochemical analyses, they indicate existence of two major evolutionary routes within the humid, cool-temperate zone.

1. (a) The first route is the direct result of acidolytic weathering of minerals under the influence of soluble organic compounds which are formed by decomposition of organic matter. This process is thus the result of induced acidification of an extrinsic character, i.e., a podzolization process.

2. (b) The second route is accomplished in a progressive manner according to a true evolutionary sequence. The geochemical mechanisms brought into play are, on the one hand, aluminization of the weathering complex as a result of the hydrolytic desaturation of clays (induced acidification) and, on the other hand, deferrification under hydromorphic conditions, i.e., a degradation process.

The fundamental distinction thus indicated between these two pedological routes serves to answer certain questions relative to genesis and classification of soils of temperate coolzones.