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ARS Home » Research » Publications at this Location » Publication #123431


item Kirk, Ivan

Submitted to: Agriculture Handbook
Publication Type: Government Publication
Publication Acceptance Date: 6/25/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: Aerial applicators of crop production and protection products need tools to assess spray droplet size and spray drift potential from their spray applications. Performance models were developed for spray nozzles in predominant use in the fixed and rotary-wing agricultural aviation industry in the USA. The models were demonstrated to provide reliable estimates of spray droplet characteristics that are useful in controlling spray drift and complying with product label specifications. The models provide information on droplet size, relative span, and percentage of spray volume in the highly driftable portion of the spray. Surveys of aerial applicators revealed that about 40 percent of the applicators wanted a printed handbook for use when computer access for the models was not possible. Data from the nozzle models were developed into a series of graphs for a printed handbook. The graphs provide essentially the same information as the computerized models. The handbook will include both the computer models on Compact Disc and the graphical presentation of spray nozzle model results. The models and graphs will be useful to aerial applicators in responsible application of crop production and protection products.

Technical Abstract: Pesticide applicators should be knowledgeable about droplet spectra classification and compliance with crop protection product labels. Some pesticide product labels already specify application with a certain droplet spectra classification, and labels for many new and reregistered products are expected to require application within a specified range of the spray droplet spectrum (e.g., Medium or Coarse). Applicators of pesticides will need to know how to achieve the specified droplet spectra classification with their application. Spray nozzle parameters, pressure, and airspeed are primary factors that influence droplet spectra classification from aerial spray nozzles. Computer spreadsheet models for spray nozzles commonly used on fixed and rotary-wing aircraft were developed that will permit applicators to select their spray nozzle, input operational conditions for an application, and the model will predict the expected droplet spectra classification. Atomization models are presented for eight of the most commonly used spray nozzles on fixed-wing aircraft and eight of the most commonly used spray nozzles on rotary-wing aircraft as determined from aerial applicator surveys. The models are included in the handbook on CD and are available on Internet pages for applicator use. These models provide a tool that applicators can use to mitigate spray drift and ensure compliance with crop protection product label requirements for applying sprays with a specific droplet spectra classification. This publication with graphical displays of model outputs from all of the nozzle models was assembled to provide aerial applicators with a reference manual for use when computer access is inconvenient or impossible.