Assessment of Different Parameters Influencing the Quality of Spray Distribution on Orchard Sprayers

In practice, optimum adjustment of sprayers requires knowledge about the interaction between a whole series of different parameters influencing application success. In this study, the following technical parameters were tested for their influence on the vertical distribution of an orchard sprayer setup: application pressure, distance from nozzle to target surface, nozzle-to-nozzle distance, nozzle type, nozzle calibre and blower-boosted application versus application without an air blower. For this purpose, an extensive measurement program with a vertical distribution test stand was conducted. The setup used allowed all mentioned parameters to be varied. The distributions achieved were subsequently assessed using the coefficient of variation (CV). With statistical analyses of variance, the extent to which variations of a single parameter influenced the CV of the distribution was determined. Because of the large differences in the CV of the vertical distribution, both nozzle types used (flat fan nozzle and hollow cone nozzle) were analysed separately. The flat fan nozzle generally showed lower CVs compared to the hollow cone nozzle. Exceptions were found at settings with the smallest distance to target surface combined with the largest nozzle-to-nozzle distances. It could be shown that the parameters nozzle-to-nozzle distance and distance from nozzle to target surface have a significant influence on CV and interact with each other. All other parameters have no or only a very small impact.