Validation of a remote sensor-based spraying strategy in hedge and goblet vineyards

• PWM-controlled smart sprayer prototype tested in hedge and goblet vineyards. • Prototype sprayer maintained effective foliar spray deposits with less spray volume applied. • Performance validated in hedge and goblet-trained vines at two growth stages during one campaign. • Product savings of 23% compared to conventional practices In line with current European efforts, several technologies are being developed to optimize the application of agrochemical products in vineyards. This work presents a first assessment of the implementation and potential of a Variable-Rate Application (VRA) prototype sprayer, equipped with Pulse-Width Modulation (PWM) valves and an onboard control system, mounted on a commercially available multi-row sprayer. It was developed to modulate the spray output based on canopy vigor maps derived from drone-acquired multispectral imagery. The processing unit interpreted these prescription maps in real time using a geolocation sensor and adjusted the application rate accordingly across the vineyard. Field trials were conducted in two common Mediterranean training systems (hedge and goblet) during two phenological stages. Foliar deposition was analyzed in canopy zones with different vigor levels. The experiment was focused on the prototype’s ability to correctly execute maps and to deliver comparable spray deposition to that a traditional constant-rate application. Prescription maps classified the vineyard into three vigor zones (‘High’, ‘Medium’, and ‘Low’), each related with a specific application rate obtained with the regulation of PWM valves by the control module, which followed the map. Results demonstrated that the prototype was able to correctly reproduce the prescription maps, adapt to the required working conditions, and successfully modulate spray flow rates according to the defined vigor zones. Spray volume was reduced by up to 40% compared to standard practices, while maintaining equivalent levels of deposition efficiency, with no significant differences observed across the two growth stages of the vegetation.