Spectral vegetation indices in the monitoring of corn ( Zea mays L.) submitted to biostimulants

Corn is a crop of great national interest, being one of the main grains in Brazil. In recent decades, research has deepened in using biostimulants, which promise to bring both quality and productivity agronomic yields. Advances in the monitoring and characterization of vast areas of corn planting are in constant development, with the use of Vant's cameras that allow the remote assessment of the state of the crop in the field. This work aimed to analyze the interaction of vegetation indices with the corn crop subjected to biostimulants. The experiment was carried out in the municipality of Areia, Paraiba, Brazil. The corn hybrid used was AG1051. The biostimulants were the pyroligneous extract, algae extract (A. nodosum), and the product based on three phytohormones, applied in three different doses, in three stages of the culture: seed, V3, V8, resulting in a 3x4x3+1 factorial (witness). The images obtained were taken using a DJI drone with an attached RGB camera 12.4 megapixels, attached, which were later processed, the plant indices calculated (NGDRI, SAVI, TGI, EXG), and extracted. The results obtained showed that there was a significant difference between the indices and the days after planting; the best productivity was related to the treatment with kinetin; Gibberellic Acid and Indole-butyric acid at a dose of 6 g/L applied in the V8 phase of the plant, and there was a correlation between the NGRDI and SAVI index and the total chlorophyll content