Pollution Reduction from a Spray Recovery Sprayer

Abstract

A spray recovery sprayer designed for apple orchards has been adapted to vineyards andcrops of similar geometry (e.g. raspberries). Design resulted from a compromise between goodcanopy penetration and leaf coverage, and high recovery. The study reported in this paper was onthe evaluation of the potential of this sprayer for reduced ground contamination and airborne drift. Acomparative study was performed where trials were conducted at the same time over the same areawith 2 sprayers: a conventional airblast radial sprayer equipped with proper baffles to target the airstream to the canopy and the spray recovery sprayer. Ten meters downwind from the test plot, three10 m towers equipped with 10 active drift samplers deployed from 0.5 to 10 m above ground wereinstalled. On the ground, Petri dishes were laid down from the spray swath to the drift towers. Twofood dyes were used in a dual-tracer technique to assess ground deposition and airborne drift.Meteorological conditions were recorded using two sonic anemometers. Results showed a 3 folddecrease in airborne drift over the wind speed range from 0.5 to 5 m/s. At a wind speed of 3 m/s, 4.4fold decrease in ground deposit was measured and ground deposition reduction decreased withincreasing wind speed. At a wind speed of 5 m/s, decrease in ground deposit associated with thespray recovery sprayer was by a factor of 2. These results clearly showed that the spray recoverysprayer could be used as an efficient tool for reducing ground losses, airborne drift and buffer zonewidths.