MODELING SOIL DEVELOPMENT IN A POST-INCISIVE CHRONOSEQUENCE

Abstract

The complex pedogenetic evolution with age is described effectively by a single multivariate model. Factor analysis of selected chemical and physical properties of four pedons representing three developmental stages of a postincisive soil chronosequence in NW Italy shows that a factorial model describes the variables adequately. Two factors, accounting for 76.9% of the overall variance, describe the evolution from the more recent Inceptisol to the older Alfisol. Factor I, linked to particle size distribution, cation exchange capacity, and the crystallinity ratio of iron oxides, was sensitive to the development of either Bt or Bx horizons and can be considered an index of soil evolution for this chronosequence. Even if age is not a direct factor in pedogenesis, the stage of evolution reached by the soils in this chronosequence is related strictly to the intensity of the pedogenetic processes over time.