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Ciclo cultural do milho: análise da cobertura vegetal utilizando índices de vegetação derivados do Sentinel-2
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Advisor(s)
Abstract(s)
Os índices de vegetação são hoje amplamente utilizados para avaliar e caracterizar a cobertura vegetal. Na agricultura estes índices permitem obter informações ao longo do ciclo cultural e atuar oportunamente, caso se justifique.
Neste estudo foram calculados diferentes índices de vegetação (NDVI - Normalized Difference Vegetation Index, NDRE - Normalized Difference Red Edge Index, EVI - Enhanced Vegetation Index) para avaliação do vigor vegetativo. Estes índices foram obtidos a partir de imagens do satélite Sentinel-2, da Agência Espacial Europeia, de maio a setembro de 2021. Esta análise incidiu sobre a cultura do milho, numa parcela situada no Ribatejo (38.994975°; -8.369681°). No processamento dos dados foram utilizados os softwares ArcGis TM e Microsoft Excel.
Este trabalho tem como objetivos: a) desenvolver mapas temáticos de índice de vegetação para avaliar a produtividade da cultura do milho; b) analisar o comportamento dos índices de vegetação ao longo do ciclo cultural; c) perceber qual ou quais os índices que são mais confiáveis nas fases mais avançadas do ciclo cultural.
A correlação entre o NDVI e o EVI foi forte (r=0,95) mas o EVI evidenciou diferenças na refletância do milho em fases do ciclo cultural em que o NDVI mostrou saturação. O NDRE apresentou uma forte correlação com o NDVI (r=0,99). Nas fases do ciclo cultural em que a cobertura do solo fica mais densa, principalmente na fase vegetativa da floração, o NDRE superou o EVI e o NDVI, mostrando ser eficiente na deteção espacial das diferenças do vigor vegetativo.
Vegetation indices are now widely used to assess and characterize vegetation cover. In agriculture, these indices make it possible to obtain information throughout the crop cycle and to act in a timely manner, if necessary. In this study, different vegetation indices (NDVI - Normalized Difference Vegetation Index, NDRE - Normalized Difference Red Edge Index, EVI - Enhanced Vegetation Index) were calculated to assess vegetative vigor. These indices were obtained from images from the European Space Agency's Sentinel-2 satellite, from May to September 2021. This analysis focused on the maize crop, in a plot located in Ribatejo (38.994975°; -8.369681°). ArcGis TM and Microsoft Excel software were used for data processing. This work aims to: a) develop thematic vegetation index maps to evaluate maize productivity; b) analyze the behavior of vegetation indices throughout the cultural crop cycle; c) understand which index or indices are more reliable in the more advanced stages of the crop cycle. The correlation between NDVI and EVI was strong (r=0.95) but EVI showed differences in maize reflectance at stages of the crop cycle where NDVI showed saturation. The NDRE showed a strong correlation with the NDVI (r=0.99). In the stages of the crop cycle in which the soil cover becomes denser, mainly in the vegetative phase of flowering, the NDRE outperformed the EVI and the NDVI, proving to be efficient in the spatial detection of differences in vegetative vigor.
Vegetation indices are now widely used to assess and characterize vegetation cover. In agriculture, these indices make it possible to obtain information throughout the crop cycle and to act in a timely manner, if necessary. In this study, different vegetation indices (NDVI - Normalized Difference Vegetation Index, NDRE - Normalized Difference Red Edge Index, EVI - Enhanced Vegetation Index) were calculated to assess vegetative vigor. These indices were obtained from images from the European Space Agency's Sentinel-2 satellite, from May to September 2021. This analysis focused on the maize crop, in a plot located in Ribatejo (38.994975°; -8.369681°). ArcGis TM and Microsoft Excel software were used for data processing. This work aims to: a) develop thematic vegetation index maps to evaluate maize productivity; b) analyze the behavior of vegetation indices throughout the cultural crop cycle; c) understand which index or indices are more reliable in the more advanced stages of the crop cycle. The correlation between NDVI and EVI was strong (r=0.95) but EVI showed differences in maize reflectance at stages of the crop cycle where NDVI showed saturation. The NDRE showed a strong correlation with the NDVI (r=0.99). In the stages of the crop cycle in which the soil cover becomes denser, mainly in the vegetative phase of flowering, the NDRE outperformed the EVI and the NDVI, proving to be efficient in the spatial detection of differences in vegetative vigor.
Description
Comunicação em painel
Keywords
EVI imagens multiespectrais NDRE NDVI vigor vegetativo multispectral images crop vigor
Citation
Grifo, A.; Palminha, A. & Ferreira, A. (2023). Ciclo cultural do milho: análise da cobertura vegetal utilizando índices de vegetação derivados do Sentinel-2. Ata de resumos da Conferência Impact Science’23, Revista da UI_IPSantarém. 11(3), 31-32. https://doi.org/10.25746/ruiips.v11.i3.32349
Publisher
Unidade de Investigação do Instituto Politécnico de Santarém