Characteristics and classification of Japanese nozzles based on relative spray drift potential

European spray nozzle drift classifications have enabled the objective evaluation of the drift reduction performance of different nozzles with various operating parameters available in certain areas. The drift potential index reduction percentage (DIXRP) for one series of drift reduction nozzles used in Japan was investigated by wind tunnel tests. Based on the reference spray (Hypro ISO F110 03), most of the YAMAHO KIRINASHI ES nozzles had DIXRP values above 50% at nozzle heights from 0.3 m to 0.5 m, which means these nozzles can be considered as drift reduction nozzles. The best nozzle height range was found to be between 0.3 m and 0.4 m above the crop canopy. In addition, the DIXRP values were above 80% for a nozzle height of 0.3 m, except for one nozzle (the ES 05) which had the smallest droplet size and low flow rate which contributed to the large decrease in the DIXRP values when nozzle pressure increased. Large droplet diameter, high droplet velocity and low recommended nozzle height are considered to be important factors that can provide good drift reduction performance although droplet velocity was not measured in this study. The DIXRP value was inversely proportional to nozzle height. In addition, the influence of nozzle size on the DIXRP values was found to be statistically significant (P < 0.01), although the influence was not as obvious as that of nozzle height. Finally, a nozzle classification system for use in Japan based on the relative drift potential has been established.

► Relative drift potential of the drift reduction nozzles used in Japan was measured. ► Nozzle height was the most obvious factor that influenced the relative drift potential. ► The influence of nozzle size on the index value was statistically significant (**P < 0.01). ► The nozzle classification system in Japan based on relative drift potential was initially established.