Dados do Trabalho

Título

SOIL EXPOSURE DYNAMICS ASSESSMENT IN CROPLANDS FROM BRAZILIAN BIOMES BY LANDSAT IMAGERY

Resumo

  The continued capacity of soil to maintain its ecosystem functions for living organisms is the concept of soil health and is directly related to crop management when considering agricultural and forestry land. Mapping the frequency of soil exposure during a certain period can indicate soil conditions. As bare soil is more affected by solar radiation than a covered soil, factors such as temperature, water, organic matter and structure tend to reduce soil health and productivity potential. Therefore, the objective of this study was to evaluate the dynamics of soil exposure in soybean and forest croplands in the Brazilian biomes of Amazônia, Cerrado, Caatinga, Pampa, Mata Atlântica and Pantanal in 2018 from the perspective of soil health. This research used the GEOS3 algorithm, which analyses a time series of Landsat imagery and builds a mask based on the reflectance of the frequency with which the soil was exposed in a period (1984-2018), generating a Bare Soil Frequency (BSF) for the Brazilian territory. To do this, we defined exposure categories according to the quartiles of the BSF, which represented the level of degradation of the biomes, taking into account soybean cultivation and forest areas. Thus, the BSF levels were: few, slightly, moderately and very exposed. In general, the frequency of soil exposure reached 64% in the Cerrado, 56% in the Atlantic Forest and 70% in the Caatinga biome. We observed that soybean areas in the Cerrado and Mata Atlântica biomes had the highest exposure frequencies in recent years, which is a warning for these areas. The highly exposed soil areas in the Cerrado were around 120,603 km², while this class covered 68,499 km² in the Atlantic Forest, indicating the lower soybean area in this biome. We observed that where the forestry is present, there is less soybean production and, therefore, less exposed soil area in certain biomes, indicating which crop impacts soil health most, as BSF levels are directly related to soil.

Palavras-chave

BSF; GEOS3; soil reflectance; Landsat.

Instituição financiadora

Programa Institucional de Bolsas de Iniciação Científica (PIBIC)/ FAPESP 2021/05129-8

Agradecimentos

Grupo de Geotecnologias em Ciência do Solo- GeoCiS