Soil Mapping of a Small Watershed in a Brazilian Savanna Biome: A Semi-Automatic Approach

Abstract

The objective of this\rwork is to propose a semi-automatic methodology for the creation of a semidetailed\rto detailed watershed’s soil map. This methodological proposal is based on the\rtraditional method (field work and photo interpretation) and on morphometric\rvariables analysis, using data originated from the Digital Elevation Model\r(DEM) of the Shuttle Radar Topography Mission (SRTM) program. The steps taken\rthrough this methodological proposal were the identification of the\rhydromorphic areas boundaries through interpretation of aerial\rorthophotographs; the compartmentalization of the relief through color\rcomposition techniques using the morphometric variables—slope, altimetry and\rhorizontal curvature; the development of a pedological database based on data\rgathered in the field; the elaboration of a preliminary soil map based on the\rcompartmentalized relief and on the dataset of the soils sampled in the field;\rthe elaboration and adjustment of the final soil map according to the\rinterpretation of aerial photographs and also the physical and chemical\ranalyses of the soils. This semi-automatic methodology demonstrated improved\refficiency in defining the soil units, reducing operation time and subjectivity\rof the process, thereby contributing to the systematization of soil mapping at\rwatershed level in scale 1:50,000, as well as, promoting better knowledge\rbetween the relation of the geomorphic and soil variables in the Brazilian\rSavanna Cerrado.