Abstract
In the field of pesticide spraying, droplet size is one of the most important factors affecting droplet deposition and drift. In order to study the effect of different droplet size parameters on droplet deposition distribution and drift of aerial spraying by using plant protection UAV, an aerial spraying test with the same spraying rate and different size droplets in rice canopy was carried out by using multi-rotor unmanned aerial vehicles (UAV) and four TEEJET nozzles with different orifice sizes (these droplets with a volume median diameter (VMD) of 95.21, 121.43, 147.28, and 185.09 μm, respectively), and the deposition distribution and penetration of droplets in the target area and the drift distribution of droplets in the non-target area were compared and analyzed. The results showed that the deposition distribution and penetration of droplets in the target area and the drift distribution of droplets in the non-target area were influenced by the droplet size. The droplet deposition rate in the upper and lower rice canopies were increased in the target area with the increase of droplet size. The penetration results of droplets also increased with the increase of droplet size, and that of droplets with a VMD of 185.09 μm was the best, reaching 38.13%. The average values of the cumulative drift rate of droplets in the rice canopy in the four tests were 73.87%, 50.26%, 35.91%, and 23.06%, respectively, and the cumulative drift rate and the drift distance of droplets decreased with the increase of droplet size, which indicated that the increase of droplet size can effectively reduce droplet drift. It demonstrated that the droplet size is one of the most important factors affecting droplet deposition and drift for pesticide spraying by plant protection UAV, and for the application of plant protection UAV with extra-low volume spraying, the use of droplets with VMD less than 160 μm should be avoided and a more than 10 m buffer zone should be considered downwind of the spraying field to avoid drug damage caused by pesticide drift. The results have fully revealed the effect of droplet size parameters on droplet deposition and drift of aerial spraying. Moreover, the influence of the wind field below the rotors on the distribution of droplet deposition was surmised and analyzed from the perspective of plant protection UAV. It is important for optimizing the droplet parameters of aerial spraying, increasing the spraying efficiency, and realizing precision agricultural aviation spray.
Highlights
Chemical control for diseases, insects, and weeds is an important agricultural production technology, and it is estimated that agrochemicals prevent up to 45% of loss from of the world’s food supply [1,2]
The average deposition rate of T4 in upper and lower rice canopy were the largest, and were significantly higher than that of T3, T2, and T1. It indicated that with increased droplet size, the droplet deposition rate in the upper and lower rice canopy were increased in the target area
The average deposition rate of droplets with a VMD of 185.09 μm in the upper and lower rice canopy were the largest, and the droplet deposition rate in the upper and lower rice canopy were increased in the target area with the increase of droplet size
Summary
Chemical control for diseases, insects, and weeds is an important agricultural production technology, and it is estimated that agrochemicals prevent up to 45% of loss from of the world’s food supply [1,2]. For this reason, that there is no report about the effects of droplet size on the distribution of droplet deposition in aerial to using that proposed by other authors in the orchard applicationsFor using machinery spraying by plant protection. This ground reason, to [36], an aerial spraying test with the same spraying rate and different sized droplets in rice canopy that proposed by other authors in orchard spray applications using ground machinery [36], an aerial was carried. Increasing the spraying efficiency, and realizing precision agricultural aviation spray
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