Nozzle classification for drift reduction in orchard spraying

In fruit growing high values of spray drift are found compared to arable field applications. In arable spraying drift reducing nozzles are certified for use as drift reducing measures. The nozzles which may potentially reduce drift in fruit growing are not jet classified as drift reducing nozzles, although they are available on the market. The development of a nozzle classification system to identify the drift reduction potential of spray nozzles used in fruit crop spraying would open this market. The results of the initial setup of a nozzle classification system for spray drift reduction in orchard spraying based on drop size measurements is described. An evaluation was made of measured drop size characteristics of a series of nozzles in reference to performed field measurements of two characteristic nozzles; Albuz lilac and Lechler ID9001. Based on these anchor points the ranking of the volume fraction of drops smaller than 100 μm (V100) of the nozzle to be classified could be scaled to yield a potential drift reduction, assuming a linear relationship between V100 and spray drift deposition. Within this system, the determination of threshold nozzles for the drift reduction classes 50%, 75%, 90% and 95% drift reduction are described. Identified threshold nozzles for these classes are TeeJet DG8002, Albuz AVI 80015, Lechler ID9001 and Albuz TVI80025 all at 7 bar spray pressure, except for the Lechler ID 9001 which is used at 5 bar pressure. These nozzles will be used in field drift measurements to validate the model