Evaluation of proximal sensing techniques and testing of variable-rate kit for sprayers to improve environmental and economic sustainability of crop protection stages

In crop protection science, variable rate application refers to the application of plant protection products at variable rates according to the size of the canopy to be sprayed. This system, therefore, adapts the spray mixture (pesticide + water) to the canopy in real time. As a result, this system enables significant improvements in spray deposition while reducing the environmental footprint simultaneously. In order to perform variable-rate application, a sensing system capable of characterising the canopy in real time is required. In recent years, many sensors have been developed that can detect the canopy, such as laser scanner, ultrasonic sensor, depth cameras and multispectral cameras. In addition, many technologies and techniques have been proposed for the acquisition and management of canopy data. Under these circumstances, the aim of this thesis is to evaluate the most promising sensors for the acquisition of canopy data (height, thickness, volume, density, foliar layers) in order to support the development and testing of a variable-rate implementation kit, based on an innovative ultrasonic sensor, with the aim of reducing the environmental footprint of crop protection operations.