Efeitos da geada sobre a resposta espectral do milho safrinha em Dourados

Abstract

The occurrence of frost is quite frequent in the Dourados region, especially during the autumn-winter season, and this is one of the main factors of decreased productivity in the region. One way to estimate the losses is through analysis using satellite images. This work aimed to evaluate the changes in the spectral response caused by frost in the corn second crop in the 2020/21 harvest, in Dourados-MS. A Geographic Database was prepared for the study area. The history of frost occurrence in the Dourados region was evaluated and the days on which the event occurred were identified. Images were obtained according to the physiological development of corn (Zea mays L.); the acquisition dates were determined based on the vegetative development of the crop until the frost incidence where the vegetative vigor began to decline. Sentinel 2 satellite images were used, in the visible to near infrared spectral bands, determining NDRE (Normalized Difference Vegetation Index in the Red Edge Band) and NDVI (Normalized Difference Vegetation Index) indices. The data were processed in QGIS 3.16.4 software in order to analyze the behavior of plants before and after frost. The occurrence of frost caused changes in the spectral response of the corn second crop in Dourados, MS, with a significant decrease in the values of NDVI and NDRE vegetation indices.