Análise comparativa da umidade da vegetação de áreas de caatinga preservada, agricultura irrigada e sequeiro

Abstract

A B S T R A C TThe unplanned use of the resources of the caatinga biome has been provoking several environmental degradation processes, which interferes negatively in the physical and biological systems of the semi-arid region. Thus, the present study aimed to analyze the biophysical differences in areas of preserved and degraded caatinga, as well as irrigated and dry farming areas. Two images of the satellite Landsat 8 -Sensor OLI, corresponding to 05/22/2016 and 17/01/2017 were made. In which the reflectance, NDVI and NDWI calculations were applied. The results showed a difference in the values of NDVI and NDWI between the images of 2016 and 2017 according to the different types of vegetation. The areas of caatinga presented predominance of NDVI values from 0.4 to 0.6. Higher NDVI and NDWI characterized irrigated perimeters than in caatinga and dryland areas. Such differences between the analyzed days were the result of the absence and/or low amount of precipitation in the months before the imaging days. As for irrigated agriculture, which has a greater availability of water, than the influence on the nature of plants and in the moisture content present in the soil. Keywords: Semi-arid, biophysical parameters, vegetation. R E S U M OO uso não planejado dos recursos do bioma caatinga vem provocando diversos processos de degradação ambiental, os quais interferem negativamente sobre sistemas físico-naturais e biológicos da região semiárida. Sendo assim, o presente estudo teve como objetivo analisar as diferenças de parâmetros biofísicos em áreas de caatinga preservada e degradada, bem como das áreas de agricultura irrigada e sequeiro. Foram utilizadas duas imagens do satélite Landsat 8 -Sensor OLI, correspondentes aos dias 22/05/2016 e 17/01/2017. Nas quais foram aplicados os cálculos de reflectância, NDVI e NDWI. Os resultados mostraram uma diferença nos valores de NDVI e NDWI entre as imagens de 2016 e 2017 de acordo com os diferentes tipos de vegetação. As áreas de caatinga apresentaram predominância de valores de NDVI de 0,4 a 0,6. Os perímetros irrigados destacaram-se por apresentar NDVI e NDWI maiores do que nas áreas de caatinga e de sequeiro. Tais diferenças entre os dias analisados resultaram da ausência e/ou baixa quantidade de precipitação

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