Use of different vegetation indices for the evaluation of the kinetics of the cherry tomato (Solanum lycopersicum var. cerasiforme) growth based on multispectral images by UAV

Abstract

Abstract This study evaluated seven vegetation indices for the monitoring of a cherry tomato crop using an Unmanned Aerial Vehicle with a multispectral camera that measures in the Green, Red, and Near Infrared spectral bands. A photogrammetric flight plan was designed to capture the spectral images every 2 weeks in two agricultural parcels identified as Treatment 1 (\({T}_{1}\)) and Treatment 2 (\({T}_{2}\)). A total of 7 photogrammetric flights were carried out for the crop monitoring and the corresponding orthophotographs were obtained using digital photogrammetry techniques. Subsequently, vegetation indices were calculated for these orthophotographs. The mean and standard deviation of these indices were extracted, and a statistical analysis was performed to compare the vegetation indices and to analyze their behavior over time. Analysis of variance (ANOVA) showed that Ratio Vegetation Index (RVI), Green Vegetation Index (GVI), Normalized Difference Vegetation Index (NDVI), Infrared Percentage Vegetation Index (IPVI), Green Normalized Difference Vegetation Index (GNDVI), and Optimized Soil-Adjusted Vegetation Index (OSAVI) indices showed significant variation (P-value < 0.05) over time. No statistically significant difference between the two treatments was found. IPVI, NDVI, and OSAVI showed less variation in pixel values. The RVI, GVI, NDVI, IPVI, GNDVI, and OSAVI indices proved to be valuable tools for monitoring field crops since these indices responded to the crop growth kinetics.