Analyses of Equipment, Meteorology and Other Factors Affecting Drift from Applications of Sprays by Ground Rig Sprayers

Studies were conducted in the field to measure off-target spray deposition rates from applications of sprays under different application (nozzle/droplet size and boom height) and meteorological conditions. The results were analyzed to investigate the effects of spray quality, boom height and wind speed on spray deposition rates. Curves are presented showing that deposition rates were greater for fine sprays than medium to extra coarse sprays, and for greater boom heights. There was not a strong correlation between deposition rates and wind speed. This was probably due mainly to the relatively far distance of the first sampling location at 25 ft (7.5 m) from the edge of the application area, and to the fact that most of the wind speeds in the studies were greater than the <10 mph (<16 km/hr) where wind speed effects would be most likely to be most evident.