Authors

Abstract

This study investigates the effect of electrostatics in UAV spraying to enhance droplet deposition efficiency during the blooming stage of apple trees. Experiments were conducted under two operating conditions - electrostatic spraying and non-electrostatic (conventional) spraying - at UAV flight heights of 1.0 m, 2.0 m, and 3.0 m above the apple tree canopy. Spray deposition was measured by placing test paper on the upper, middle, and lower canopy layers, on both the front and the back sides of the leaves. The results show that, compared with conventional UAV spraying, electrostatic force increased droplet number density by 17.6% and reduced droplet size by 25.3%, thereby improving overall spray performance. This provides notable advantages for pollination and pest control during the early growth stage of apple trees. The electrostatic charge generates an attractive force between charged droplets and the target surface, enhancing droplet adhesion and deposition on the back side surfaces of lower leaves and flowers. However, this advantage is not significant on the back sides of upper and middle canopy leaves due to limited recirculating airflow reaching those locations. These findings support the application of electrostatic technology to improve pollination efficiency and precision pesticide spraying during the early developmental stage of apple trees.

Abstract in Chinese

本研究旨在探究苹果树花期无人机喷雾中静电效应对提升雾滴沉积效率的作用。试验设置静电喷雾与非静电（常规）喷雾两种工况，并在距离苹果树冠层上方 1.0 m、2.0 m 和 3.0 m 的不同无人机飞行高度下进行试验。通过在冠层上、中、下不同层次的叶片正反面布设喷雾采样纸，对雾滴沉积分布进行测定。结果表明，与常规无人机喷雾相比，静电力可使雾滴数密度提高 17.6%，雾滴粒径减小 25.3%，从而提高喷雾效果，在苹果树生长早期的授粉及病虫害防治方面具有明显优势。静电作用在带电雾滴与靶标之间产生吸引效应，可增强雾滴在下层叶片背面或花朵的黏附与沉积。然而，由于回流气流难以到达冠层上部和中部叶片背面，该静电优势在这些部位并不显著。上述研究结果为在苹果树生长早期利用静电技术提升授粉效率或开展精准农药喷施提供了支撑。