Optimization of the factors affecting droplet deposition in rice fields by rotary unmanned aerial vehicles (UAVs)

Unmanned aerial vehicles (UAVs) are widely used in modern agricultural management for aviation spraying. Many factors affect the droplet deposition during quadrotor UAV application. To explore the importance of these influencing factors on the droplet deposition effect, this article classified all the factors and determined the core influencing factors. An orthogonal experiment was then designed to explore the importance of each core influencing factor on the droplet deposition effect. The importance of three factors on the droplet deposition volume decreased in the following order: flight parameter (F = 518.688), droplet size (F = 123.813) and crop phenotype (F = 83.688); likewise, the importance of these factors on the droplet deposition uniformity decreased in the following order: flight parameter (F = 31.868), crop phenotype (F = 15.442) and droplet size (F = 9.105). The droplet deposition volume and droplet uniformity should both be considered to determine the optimal application scheme. The results also showed that the overall droplet deposition distribution trend was similar at each sample point on each collection line. Plant deformation with a larger area or deeper depth helped the droplets deposit onto the crop canopy.