Modeling soil development in a post-incisive chronosequence

The complex pedogenetic evolution with age is described effectively by a si ngle multivariate model. Factor analysis of selected chemical and physical properties of four pedons representing three developmental stages of a post incisive soil chronosequence in NW Italy shows that a factorial model descr ibes the variables adequately. Two factors, accounting for 76.9% of the ove rall variance, describe the evolution from the more recent Inceptisol to th e older Alfisol. Factor I, linked to particle size distribution, cation exc hange capacity, and the crystallinity ratio of iron oxides, was sensitive t o the development of either Bt or Bx horizons and can be considered an inde x of soil evolution for this chronosequence. Even if age is not a direct fa ctor in pedogenesis, the stage of evolution reached by the soils in this ch ronosequence is related strictly to the intensity of the pedogenetic proces ses over time.