Development and Evaluation of Functional Soil Mapping Unit Using Pedostructure Hierarchy Concept

Abstract

Accurate soil characterization is crucial for understanding soil-water interactions and allowing for better on-farm agricultural and environmental management. Current soil characterization methods lack quantitative attributes that integrate the soil mapping units with environmental and agronomical models. In this research we proposed a methodology to physically characterize the soil water medium using quantitative parameters. We incorporated the continuously measured soil water potential curve and the soil shrinkage curve to extract the physically based pedostructural (PS) parameters needed for characterizing the soil water medium. We present a methodology to generate and define functional soil mapping units that possess physical and quantitative parameters. We followed a four step general system hierarchical approach overlaying study area map, landform map, and SSURGO map. The fourth step was to validate the generated functional soil units using discriminate analysis performed on the PS parameters extracted for every soil mapping unit. Results of this study show that surface horizon (Ap) have higher PS parameter values than subsurface horizon Bt. The PS concept showed high capabilities in defining the soil mapping units, as concluded from the discriminate analysis that was performed.