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Title: The influence of nozzle type, operating pressure, and tank-mixture components on droplet characteristics and the EPA's drift reduction rating

Author
item HENRY, RYAN - University Of Nebraska
item Fritz, Bradley - Brad
item Hoffmann, Wesley
item KRUGER, GREG - University Of Nebraska

Submitted to: Journal of ASTM International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2016
Publication Date: 12/10/2016
Citation: Henry, R., Fritz, B.K., Hoffmann, W.C., Kruger, G. 2016. The influence of nozzle type, operating pressure, and tank-mixture components on droplet characteristics and the EPA's drift reduction rating. Journal of ASTM International. doi:10.1520/STP159520150098.

Interpretive Summary: Understanding how the spray systems interacts to form the resulting droplet size in a spray application is crucial to optimizing its setup to mitigate spray drift. EPA's recent drift reduction technology program looks to encourage applicators to use technologies shown to reduce drift, however testing and evaluation of these technologies is a significant undertaking requiring standardized methods and metrics to fully understand to role each component of a spray system plays in controlling droplet size. To further understand how these components interact, multiple combinations of nozzle type, spray pressure and spray solution were measured for droplet size and the results used to determine which factors had the greatest influence and how each interacted with each other. The results showed that nozzle had the greatest influence on droplet size but the combination of nozzle, spray pressure and spray solution must be considered to fully understand the spray resulting from an application.

Technical Abstract: The introduction of drift reduction technology (DRT) guidelines by the U. S. Environmental Protection Agency (EPA) has established testing protocols for nozzles, agrochemicals, application parameters, and combinations thereof for applying agrochemicals by certified individuals in the United States. The Pesticide Application and Technology Laboratory in North Platte, Nebraska, sought to develop a large database of droplet spectrum data in regards to agrochemical applications by ground systems. The results of this study indicated that nozzle type had the greatest impact on the droplet spectrums measured. DRT star ratings ranged from zero to four, depending upon nozzle selection and adjuvant inclusion. The results of this study indicated that factors that affect a droplet spectrum, including nozzle type, tank-mixture components,and operating pressure, should be tested together when submitting data to the EPA.