Spray Drift Reduction Technology Adjuvant Evaluation

Abstract

Twelve commercial drift reduction agents were evaluated for their characteristics in the three most commonly accepted parameters for spray droplet size formation—extensional viscosity, dynamic surface tension, and kinematic viscosity. Samples were sprayed in both water and in the presence of a commercial herbicide formulation. The spray droplet spectra for these agents were then determined under rigorous control, in still-air conditions, using a Sympatec HELOS/KF laser diffraction particle size analyzer. Spraying an actual pesticide formulation that contains a wetting agent is important because the surfactant present reduces dynamic surface tension and can significantly reduce spray droplet diameter. The aerosol particle size distributions were measured using an electronic actuator that moved the nozzle spray pattern through the laser in a reproducible manner. There are multiple mechanisms that can influence both volume mean diameter and percent fines below 105 microns. There are natural and synthetic water-soluble polymers that function by increasing extensional viscosity. There are oil products that produce emulsions that keep small spray drops from forming. The droplet spectra for the different commercial products were grouped according to their specific drift reduction mechanism in order to see if a better correlation could be made on how they individually affected the resulting droplet particle size distribution.

A Review of the Current Unmanned Aerial Vehicle Sprayer Applications in Precision Agriculture

“…Adding an adjuvant also improves the control efficacy period of UAV spraying, even with reduced pesticide dosage (Meng et al, 2018). Adjuvants can also minimize droplet drift by controlling the spray liquid's physical and chemical properties, including wetting, spreading, adhesion to the target, reducing evaporation, volatilization, and spray drift (Elsik et al, 2010).…”

Effect of Application Height and Ground Speed on Spray Pattern and Droplet Spectra from Remotely Piloted Aerial Application Systems

“…The spray droplet spectra were relatively small for both the MG-1 and V6A aircraft and would have a relatively high drift potential compared to other nozzles. Although we did not investigate the drift potential of spray droplets, research data obtained from computer modeling and field experiments under varied environmental conditions indicated that spray droplets in this range that are less than 200 µm have a higher drift potential than larger droplets, with the smaller droplets having the greatest potential to drift [34][35][36][37][38][39]. While the nozzles tested in this study were original equipment manufacturer (OEM) nozzles, other nozzles, with a lower drift potential, could be installed by users to obtain a larger, less-driftable spray droplet spectrum.…”

Drift potential of UAV with adjuvants in aerial applications

“…Adjuvants can minimize or eliminate many spray application problems by controlling physical and chemical properties with specific functions, including wetting, spreading, sticking, reducing evaporation, volatilization and also spray drift [10] . Deviation in absolute values of spray droplet size and drift reduction are possible for different products of the same formulation type.…”