Use landsat image to evaluate vegetation stage in sunflower crops

Remote sensing is of great interest for the study and characterization of the vegetation and of the agricultural crops, in order to monitor them and to develop predictable patterns regarding the evolution of the crops and also for the purpose of the decision making process in real time. The main purpose of this research was the study of the sunflower crops dynamics based on spectral information obtained from satellite images. Vegetation dynamics was differently expressed by the indexes NDVI, NDBR and NDMI determined based on spectral information. NDVI has registered an ascending slope since the beginning of the vegetation period until the flowering (65 BBCH code) when the maximum value was recorded (NDVI GS6 = 0.4074). Later the distribution of this indicator recorded a descending slope until the physiological maturity. NDVI in correlation with the NIR band had lower values in the stages 12-14 BBCH code (p<0.01; R 2 = 0.642) and 80-81 BBCH code (p<0.01; R 2 = 0.605) and higher values at flowering stage, 65 BBCH code (p<0.01; R 2 = 0.966), and physiological maturity, 92-97 BBCH code (p<0.01; R 2 = 0.993; F = 3148.2). NDVI index has most closely correlated with vegetation phenophases and it highlighted, by the different level of correlation with the spectral information, the dynamics and variability in the sunflower crop.