Submitted to: National Agricultural Aviation Association Meeting
Publication Type: Proceedings
Publication Acceptance Date: December 4, 2006
Publication Date: December 4, 2006
Citation: Fritz, B.K. 2006. Atmospheric and stability effects on aerially applied agricultural sprays-Preliminary results. In: Proceedings of the National Agricultural Aviation Association Meeting, December 4, 2006, Orlando, Florida. Paper No. AA06-006. Interpretive Summary: Drift from aerial application of crop protection materials is influenced by many factors such as wind speed, temperature, relative humidity, and atmospheric stability. Applicators are responsible for making all possible efforts to reduce drift. Generally, greater drift has been associated with greater atmospheric stability. Field trials were conducted to assess the amount of downwind deposition and airborne concentration from aerial spray applications for various meteorological and atmospheric stability conditions. Preliminary results indicate that greater wind speed increased transport distance of sprays, especially the larger droplets, resulting in increased downwind deposits. These results help applicators make informed decisions that will result in more efficacious applications with minimum off-target drift.
Technical Abstract: Drift from aerial application of crop protection materials is influenced by many factors such as mean wind, temperature, relative humidity, and atmospheric stability. The applicator is responsible for making all possible efforts to reduce drift. Atmospheric conditions and stability must be considered and adjusted for on the basis of real-time observations and past experience. The objective of this research was to further document the effects of atmospheric conditions and stability on the deposition, drift, and deposited droplet size characteristics of aerial sprays. Twelve replications using a fine aerial spray treatment were conducted over the course of a day. Ground deposition and airborne concentrations at multiple heights were collected at multiple downwind locations using mylar cards and nylon screen cylinders, respectively. Preliminary results indicated that wind speed was more dominant than stability, and increased wind speed resulted in increased downwind ground deposition, suspended concentrations, and transport of larger droplets downwind.