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Keywords: Air assist spraying, Applicators, Atmosphere stability, Mass balance, Reference sprayers, Spray deposition, Spray drift, Spray sampling

1 Purpose and Scope

1.1 This Standard establishes a test procedure for use in measuring and reporting in-swath and out-of-swath ground deposits from sprayers. It does not prescribe a procedure for calibration of sprayers. This Standard recommends the minimum necessary measurements and does not preclude other measurements that might be of value.

1.2 This Standard pertains to three types of sprayers (ground, orchard and aerial) applying agricultural chemicals in a swath. It does not pertain to foggers or other sprayers where the spray is not intended to be deposited in a swath on the land surface or crop canopy. For purposes of this Standard, a ‘test‘ will consist of the application of spray and the measurement and recording of all required or needed deposit, operational, equipment, and weather data. A ‘test‘ may consist of either one or more than one pass of the sprayer(s) over a specified land area.

1.3 This Standard allows for two procedures: 1) a limited number of tests to be run when a reference spray application is used in conjunction with another sprayer/formulation of interest (both tests run temporally close to each other for co-variant statistical analysis) or 2) no reference spray application is required when a substantial number of tests (25 minimum is suggested for a statistical analysis purposes) are to be run at the same test site. Procedure (1) will permit the direct comparison of the drift from a given sprayer/formulation combination with that caused by the reference spray application. The reference spray application and the test application shall be made temporally close to each other in order to ensure equality of meteorological conditions. The chemicals or tracers used with the test and reference sprayers must not interfere with one another since spray from both will be deposited on each target. Procedure (2) permits the development of a reasonably large database for the purpose of developing and/or testing a drift model. Procedure (2) may also be used in conjunction with a reference spray application. Either procedure can be used for single pass-single swath or multiple pass-multiple adjacent swath tests.