Adjuvant Effects on Spray Characteristics and Drift Potential

This paper describes studies that were conducted to investigate the effects of different surfactant and emulsion adjuvant chemistries and formulations on spray characteristics and drift potential of a commercial herbicide. Previous research has shown that surfactant, emulsion, and polymer adjuvants can affect the formation of sprays and liquid distribution patterns when atomized through flat fan nozzles. The present research involved the application of various different tank mix-adjuvant combinations through flat fan, disc-core, and air induction nozzles. The sprays were characterized using spark photography, droplet size analysis, liquid patternation, and driftability measurements in a wind tunnel. Atomization was related to the physical properties of the tank mixes and sheet breakup mechanisms. The results will help in the development of ASTM test guidelines for spray characterization and drift research, and provide valuable information for applicators to consider when selecting tank mix-nozzle combinations for the application of agricultural chemicals.