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Relationship between soil degradation and soil classes evaluated by a 27 years Landsat image (Vis-Nir-Swir-Tir), derived from climate and digital elevation model, as to assit on digital soil mapping

Grant number: 18/09656-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): July 01, 2018
Effective date (End): June 30, 2019
Field of knowledge:Agronomical Sciences - Agronomy
Principal Investigator:José Alexandre Melo Demattê
Grantee:Claudia Maria Nascimento
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
Associated research grant:14/22262-0 - Geotechnologies on a detailed digital soil mapping and the Brazilian soil spectral library: development and applications, AP.TEM


Increasingly, studies on the processes of soil degradation are becoming essential for preservation of environmental and social factors. It was estimated by the Food and Agriculture Organization of the United Nations (2015), that 30% of the global soils are degraded, demonstrating the huge importance of studies in this aspect. For this purpose, this work will determine the relationship of soil degradation with the factors that affects it, in order to analyze the features and the importance of environment in this process of degradation. This work will be developed in an area of 4,815 km2 at São Paulo State, and the steps are going to be as follows: a) it will be collected images of the area, obtained by a 27 year time-series of satellite images (Landsat) and based on a novel technique it will be determined the areas with exposed soil; b) it was collected 4,679 soil samples (0-20 cm) to construct models of soil attributes. It will be quantified the soil properties, such as clay and cation exchange capacity, based on pixel spectra signature; c) the technique also indicated how many times a single pixel was with bared soil during the period; d) it will be also determined the surface temperature based on thermal band; e) and the climate information (water balance); f) using elevation model it will be created the layers LS factor, drainage density, topographic wetness index and solar radiation. All factors are going to be balanced and overlapped (GIS) to generate an SDI (values from 1, low risk to 5, high risk). In this way, it will be possible to evaluate the areas of the region considered as degraded and what factors may influence the most this loss. (AU)