Pedometric tools to characterize soil granulometric composition from hydromorphical soil profiles

Abstract

The objective of this work was to evaluate pedometric tools to characterize the particle size distribution (sand, silt, and clay) and to compare the profiles of hydromorphic soils. The study was carried out in the Guapi-Macacu watershed, in the state of Rio de Janeiro, Brazil. The slice-wise algorithm was applied to slice the profile data at 1-cm intervals, and the equal-area spline function for database harmonization, according to six predefined depth intervals. The analysis of the soil profile collection, using the soil-depth functions (slice‑wise and spline) and the similarity analysis, revealed that Alfisols and Entisols are relatively shallow and have coarse texture in the topsoil layer and a more irregular distribution of clay and silt along the soil profile.
These two orders usually occur in the watershed area related to floodplains, valleys, and footslopes. Fluvisols had higher amounts of clay and silt in the topsoil layer, which decrease with soil depth, and they are deeper and occur in alluvial terraces. The approach allowed to characterize the variability of texture along hydromorphical soil profiles and to perform a similarity analysis between soil orders, which can support the differentiation of soil mapping units and the identification of quantitative criteria for soil classification.