Droplet spectrum of a spray nozzle under different weather conditions

The pesticides spraying are always susceptible to losses by evaporation and drift of sprayed droplets. With these losses, low amount of the pesticide will reach the target and consequently the pest control may not be efficient. Due to these concerns, this study aimed to study the interference of meteorological conditions on droplets spectrum produced by hydraulic spraying. To carry out this work, an experimental system was built, which was consisted of: particle size analyzer, nozzle (Jacto JSF 11002), stationary sprayer, gas heater, wind tunnel, climate chamber, with the purpose of maintain an internal psychometric condition similar to the air that was coming out of the wind tunnel, bowl and temperature and RH sensors. The meteorological conditions for this work were comprised by vapor pressure deficits (VPD) of 5, 9.4, 20, 30.6 and 35 hPa and air velocities of 2, 3.6, 7.4, 11.2 and 12.8 km h -1 . The work statistic was carried out by using the Central Composite Rotational Design and data were related through the Response Surface Methodology. The wind causes so pronounced drift of the finest droplets that affects the behavior of the entire droplets spectrum, in addition to disguise the effect of VPD. However, it can be concluded that drift and evaporation act on the coarsest droplets.