Multi-temporal High Resolution Unmanned Aerial Vehicle (UAV) Multispectral Imaging for Menthol Mint Crop Monitoring

Unmanned Aerial Vehicle (UAV) technologies have nowadays become an emerging tool for the agricultural field monitoring. In this study we demonstrated the UAV remote sensing technology for menthol mint crop monitoring. UAV fitted with multispectral and thermal camera was flown over the study area during the crop growing period (May & June 2019). The high resolution multispectral images were orthomosaicked and thematic maps of popular vegetation indices (VIs) viz., NDVI (Normalized Difference Vegetation Index), GNDVI (Green Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge) were generated to assess the health status of menthol mint crop. These indices (NDVI, GNDVI and NDRE) are sensitive towards crop biophysical properties like nitrogen, chlorophyll, vigor and biomass etc. Results show that the highest value for NDVI, GNDVI, and NDRE were obtained during crop maturity period and GNDVI index was found to be the most suitable indicator for menthol mint crop health assessment. Furthermore, all the indices values were increasing with crop growth stages, clearly indicating the presence of high biomass and chlorophyll in the maturity stage as compared to the early growth stages.