ÍNDICES DE VEGETAÇÃO E SUA CORRELAÇÃO COM A PRODUTIVIDADE DA CULTURA DA SOJA EM ÁREA IRRIGADA E DE SEQUEIRO

This study aimed to map the spectral response of soybeans during its development cycle, based on the calculation of the vegetation indices NDVI, NDMI, and NDRE in irrigated crops and rainfed crops in an agricultural year with water deficit; map the spatial variability of soybean yield in irrigated and rainfed crops; and evaluate the spatial correlation between vegetation indices and soybean yield. The study was conducted in a commercial cultivation area in Cachoeira do Sul, which had a water deficit for a year. Vegetation indices were obtained from the Crop Monitoring platform, which is available online and free of charge. Soybean productivity was mapped using a grain harvester with a mapping system. Statistical and geostatistical analyses were carried out using the computer programs Statistic (version 7) and QGIS 3.28 (Firenze). All vegetation indices showed a significant spatial correlation with soybean productivity. In rainfed cultivation, the NDVI, NDMI, and NDRE indices showed a positive and significant correlation with soybean productivity at 43 and 48 days after sowing. The NDVI, NDMI, and NDRE indices in irrigated cultivation showed a positive and significant correlation with soybean productivity 128 days after sowing.