ARS | Publication request: DRIFT CONTROL MODELS HELP AERIAL APPLICATORS PERFECT SPRAY PATTERNS

Submitted to: American Society of Agricultural Engineers Resource Magazine
Publication Type: Review Article
Publication Acceptance Date: September 28, 2001
Publication Date: N/A

Technical Abstract: Crop protection product labels are now being written with spray droplet spectra classification terms that have specific definitions relative to range of spray droplet size in which the product must be applied. The directions for use on product labels have the force of law. Consequently it is imperative that pesticide applicators understand the terminology and have means for establishing spray system performance for producing sprays with droplet spectra classifications as specified on product labels. Ground applicators can use charts supplied by nozzle manufacturers for droplet spectra classification, but aerial applicators need additional information to attain label specifications because of the tremendous influence of airspeed on spray droplet size and droplet spectra classification. Spray nozzle atomization models were developed for spray nozzles in predominant use in the agricultural aviation industry in the USA. The models were demonstrated to provide reliable estimates of spray droplet spectra parameters that are useful in controlling spray drift and complying with product label specifications. The models provide information on droplet size, relative span, percentage of spray volume in the highly driftable portion of the spray spectrum, and droplet spectra classification. This information will be useful to aerial applicators in responsible application of crop production and protection products.