Cost-effective tools are needed to follow plant health status and optimize the use of water, fertilizers, pesticides and management operations. Optical methods present an attractive option to follow plant health status as they can be measured from a distance. Sensors to monitor the greenness of vegetation are readily existing and commercialized. Greenness is however a very slow indicator of plant health. Here we investigate the potential of two advanced optical indices that should respond to plant health status instantaneously: the photochemical reflectance index (PRI), and the emission of solar-induced chlorophyll fluorescence (SIF).
Together with stakeholders we identify and co-design a number of case-studies to test our methods. We tested the potential of these optical indices using leaf-level measurements. The results revealed that both PRI and SIF responded to the stress treatments much better than greenness indices. Next, we will test the methods on board a drone platform.