Author
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Kirk, Ivan |
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Submitted to: American Society of Agricultural Engineers
Publication Type: Proceedings Publication Acceptance Date: 6/24/2003 Publication Date: 7/27/2003 Citation: Kirk, I.W. 2003. Spray mix adjuvants for spray drift mitigation - progress report. In: Proceedings of the American Society of Agricultural Engineers Annual International Meeting, July 27-30, 2003, Las Vegas, Nevada. 2003 CDROM. Interpretive Summary: Off-target drift of sprays applied for crop production and protection is a significant issue related to damages caused outside of sprayed areas. Spray droplet size is a major factor influencing off-target drift of sprayed materials. Spray mix adjuvants are marketed for reducing spray drift. The primary effect of these adjuvants is increasing spray droplet size. Simulated agricultural sprays were atomized in a wind tunnel with drift reduction adjuvants in the spray mix at rates and conditions typical of aerial spray application. The effectiveness of the adjuvants in increasing spray droplet size is different for different adjuvants. The adjuvants, except for one, increase spray droplet size and would reduce spray drift. Thus, with the single exception noted in this study, applicators can balance adjuvant rate, performance, and cost for mitigating spray drift with drift reduction adjuvants. Technical Abstract: Numerous drift reduction adjuvants and spray deposition aids are available to applicators of crop production and protection chemicals. Performance of many of the newly introduced drift control adjuvants has not been well documented for aerial application. Since there are no product labeling or efficacy regulations for these adjuvants, applicators must rely on experience or information in the technical literature for evaluating their performance. Several new drift control adjuvants were selected for atomization studies in a wind tunnel to document their performance as applicable to aerial application. Spray droplet size is the primary factor influencing spray drift that applicators can control. Atomization performance of spray adjuvants in a wind tunnel is closely related to their performance under field conditions. The adjuvants were mixed at the highest recommended label rate in a blank emulsifiable concentrate tank mix. Atomization data were collected with a laser spectrometer on the first and eighth passes through a gear pump. The eighth pass simulates any effect of shear breakdown and loss of effectiveness of the adjuvant from circulation in the spray tank during application. Most of the adjuvants move the droplet spectra classification from fine to medium. The most effective adjuvant moved the droplet spectra classification from fine to coarse. This performance information will aid aerial applicators in selecting drift reduction agents to meet the drift mitigation criterion for a given application. |
