Modelagem da profundidade de Neossolos derivados de rochas graníticas do Sul do Rio Grande do Sul

Abstract

Regosols and Leptosols are characterized by low pedogenetic development, where most often they are identified by the absence of subsurface horizon B. In general, they are shallow soils and that can present great susceptibility to degradation, if used inadequately, and aiming at their conservation, it is of great importance the type and depth of contact of these soils. However, to obtain these data, it is necessary to use techniques that allow a faithful and viable representation. The alternative is the use of environmental and soil data modeling, widely known as Digital Soil Mapping (DSM). The present work aims to generate morphology and distribution data of Regosols and Leptosols derived from granite rocks in southern Brazil, using the DSM technique, where modal profiles of the area were described, and the spatial variability of the classes and the variation of the depth of lithic contact were determined. The study was conducted in an area of 54.2 ha in the municipality of Pelotas, had the description of eleven soil profiles and thirty-nine sampling points using them for the "Random Forest" modeling, together with forty-four environmental covariates extracted from the Digital Elevation Model (DEM) in a first modeling, and a second modeling with only the 10 most important covariates. The model obtained an R2 of 0.93 and an RMSE of 0.08 m, while the predicted map had an R2 of 0.72 and an RMSE of 0.17 m. Covariates that best describe the variation of Regosols and Leptosols derived from granites were related to drainage, such as normalized height, standardized height and convergence index, and the depth of the valley and elevation. standardized height and convergence index, and the depth of the valley and elevation.