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ARS Home » Research » Publications at this Location » Publication #96634
Title: VARIABLES AFFECTING SPRAY DROPLET SIZE

Author
item Hanks, James
item WILLS, GENE - DELTA RES. AND EXT. CTR.
item MACK, ROBERT - HELENA CHEMICAL CO.
item UNDERWOOD, ALLEN - HELENA CHEMICAL CO.

Submitted to: International Symposium on Adjuvants for Agrochemicals
Publication Type: Proceedings
Publication Acceptance Date: 7/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Spray droplet size is a major factor influencing the potential for drift with agrochemical applications. Many variables affect droplet size associated with a specific application, some can be controlled by the operator while others cannot. The operator has control over the type of equipment used and material that goes into the tank, but no control over environmental conditions. Each has an effect on spray droplet size and potential for drift. Spray droplet analyses indicated nozzle type, herbicide, spray adjuvant, and drift reducing agents had varying affects on spray droplet size, therefore on drift potential during application. Herbicides and spray adjuvants produced only minor changes in spray droplet size, whereas nozzle type and drift reducing agents had significant effects on spray droplet size. Care must be exercised in selection of drift reducing agents since there was a broad array of results and the potential of adversely affecting spray pattern with the addition of these products. These results indicate proper nozzle selection could be a major factor in reducing drift potential when applying herbicides.

Technical Abstract: Spray droplet size and the potential drift associated with spray application was effected by nozzle type, adjuvant, and herbicide. Spray droplet analyses were conducted with a Malvern 2600Lc laser droplet analyzer. At a spray pressure of 276 kPa, TeeJet XR110015VS and TT110015 nozzles produced 38 and 16 percent spray volume in droplets less than 105 microns, respectively. The spray adjuvant X-77 added to water had no effect on the percent spray volume in droplets less than 105 microns, whereas Induce produced 8 percent less spray volume in droplets less than 105 microns. Cyanazine slightly increased the percentage of spray volume in droplets less than 105 microns, whereas MSMA, glyphosate, and clethodim decreased the spray volume in droplets less than 105 microns. The percent spray volume in droplets less than 105 microns ranged from 7 to 37 percent when applied with a TeeJet XR110015VS nozzle at a pressure of 276 kPa. Drift reducing adjuvants were subjected to repeated passes through a centrifugal pump with droplet analyses conducted after each pass. Two of the adjuvants were not effected by the pump, whereas effectiveness of the other six was decreased with each pass through the pump.