Comparison between drift test bench results and other drift assessment techniques

The effects of application speed, boom height and spray characteristics on drift reduction potentials were measured using a drift test bench ISO/FDIS 22369-3 under controlled indoor conditions using a fully automated spray track. The results were compared with those from other drift assessment means. Tests confirmed the already known effects of nozzle type, spray pressure and boom height on drift potential with drift reduction potential values ranging from -127.7% up to 93.7%. A good correlation between drift reduction potentials from the test bench (DRP_B) and the wind tunnel measurements (DRP_W) was found which was less the case for the field experiments (DRP_F). In addition, a good correlation between V₇₅ and DRP_B was found with an R² of 0.93. By presenting spray deposition curves on the test bench as a function of time between passing of the spray and uncovering the collectors, the effect of speed on drift potential was assessed which was in contrast with the field drift measurements probably because of the limited wake effects. This approach should be further investigated with real sprayers and with an adapted methodology (actuator position, test bench length).