Deposition and Air Speed Patterns of Air-carrier Apple Orchard Sprayers

Abstract

Semi-dwarf apple trees were treated with foliar micronutrients using two different forms of orchard air-carrier sprayers. The effects of fan speed, travel speed, and spray emission patterns on in-canopy air speed and spray deposition were evaluated. The FMC Economist fan outlet air speed did not significantly affect deposit patterns. Deposit levels and patterns were influenced by changes in the spray emission pattern and by the position of the fan and nozzle manifold assembly. An 8% difference in the output between the upper and lower half of a nozzle manifold on the FMC Economist sprayer did shift, although not significantly, the vertical spray deposition in the canopy. The raised fan and nozzle manifold assembly of the Friend Air Kadet II produced the best vertical distribution of spray deposits. Increasing travel speed from 0.9 to 1.3 m/s did not significantly decreased air speed within the trees. In-canopy air speed measurements followed patterns similar to the spray deposits but there was not a good correlation between air speed and one-pass spray deposit.