Influence of Spray Parameters of a UAV Sprayer on Droplet Size in Paddy Spraying

Unmanned aerial vehicles (UAVs) have emerged as promising technologies for agricultural applications, including pesticide spraying in paddy fields. Droplet size is a critical factor influencing the effectiveness and efficiency of pesticide application. This study investigated the impact of various spray parameters of UAV sprayers on droplet size during paddy spraying. The experimental setup involved a UAV equipped with different nozzle types (flat fan nozzle, hollow cone nozzle and spinning disc nozzle), operating at varying forward speeds (2, 3, 4, 5 and 6 m s-l) and spray heights (l, 1.5, 2, 2.5 and 3 m above the crop canopy). The results demonstrated that among the three operational parameters, the type of nozzle had a significant effect on the droplet size, whereas the forward speed and height of the spray were not significantly different. A larger droplet size was obtained for the flat fan nozzle, followed by the hollow cone and spinning disc nozzles. These findings provide valuable insights for optimizing UAV sprayer settings to achieve the desired droplet size distributions and improve pesticide application efficiency in paddy fields.