Impact of sprayer drone flight height on droplet spectrum in mountainous coffee plantation¹

Impacto da altura de voo de drone pulverizador no espectro de gotas em café de montanha

HIGHLIGHTS:

The parameters influenced by the flight height were Dv_0.1, numerical median di-ameter, and coverage percentage.

Lower coverage percentage values were observed at the working height of 4 m.

Since there is an increase in flight height, the droplet diameter decreases to the parameters Dv_0.1 and NMD.

ABSTRACT

Weather conditions and sprayer operating parameters influence spray quality. Unmanned aerial vehicles are considered a modern, useful, and very efficient technological tool in the application of pesticides, as they carry out punctual spraying, and reduce environmental and public health problems. The objective of this study was to characterize the spraying quality carried out with an unmanned aerial vehicle as a function of flight height and target position in a coffee plantation in a mountainous region. Three flight heights (2.5, 3.0, and 4.0 m) were used, and the targets were placed at the top and bottom of the plant. For each plant, six water sensitive papers were placed on top of the plant and six were placed at the bottom. CIR 1.5 software was applied to determine the coverage percentage, drop density, volume median diameter, volumetric diameter corresponding to 10 and 90%, numerical median diameter, and relative amplitude. The results showed that the flight height only influenced the parameters of the volumetric diameter corresponding to 10% of the volume, numerical median diameter, and coverage percentage. The target position on the canopy influenced all the evaluated spraying parameters. In mountainous coffee plantations, the spraying system using unmanned aerial vehicle spraying is more efficient for the lower part of the plant.

Key words:
coverage percentage; drop density; droplet size