Influence of Nozzle Type and Wind Speed on Deposition and Interception of Pesticide Spray Drift: A Case Study with Atrazine

Abstract

A wind tunnel study was conducted to compare spray drift deposition and interception profiles across ASABE (American Society of Agricultural and Biological Engineers) coarse, very coarse, and extremely coarse drop size distribution (DSD) categories as a function of wind speed. AAtrex 4L (atrazine) was used as the spray solution; disk (deposition) and rod (interception) sampling devices were deployed at multiple distances and subject to spray drift at multiple wind speeds. Drift deposition was equivalent for the coarse spray delivered at 10 mph [16.1 km/h] and the extremely coarse spray delivered at 15 mph [24.1 km/h]. Intercepted (airborne) drift was indistinguishable between the coarse spray delivered at 10 mph [6.2 km/h] and very coarse spray delivered at 15 mph [6.2 km/h], and very coarse spray delivered at 10 mph [6.2 km/h] and extremely coarse spray delivered at 15 mph [24.1 km/h]. Regulatory decisions regarding potential buffer/setback mitigations would benefit from leveraging results regarding nozzle and wind speed relationships reported in this study and others to better utilize available experimental drift data (e.g., field studies/bioassays) generated with a single nozzle but at wind speeds exceeding the label specification.