Standard Test Method for Spreading of Liquid Agricultural Spray Mixtures

Abstract

5.1 This test method is intended to provide a rapid means of determining the relative ability of a liquid agricultural spray mixture to spread on a test substrate. 5.2 This test method was validated using Parafilm M3 as a test substrate. It is the user's responsibility for determining the validity of this test method for alternative test surfaces. While it may be generally agreed upon that there is no perfect model for the variety of surfaces for which spreading information would be useful, this test method does not limit users to any one surface. Further consideration must also be given to the potential effect that the liquid droplet may have on the chemical composition and morphology of the test surface. While this does not restrict the test method, an understanding of this potential can help in the interpretation of test data. 5.3 This test method will determine the relative spread of radii of water, fertilizers, oils, and mixtures of these carriers with surfactants. It is the user's responsibility to determine the validity of the test method with alternative liquids. 5.4 This test method will determine the relative spread radii of droplets over 30 s, 60 s, and 5 min. It is the user's responsibility to determine the validity of the test method at alternative spreading times. 5.5 This test method is appropriate for relative humidities within the range of 40 % to 70 %. It is the user's responsibility to determine the validity of the test method at alternate relative humidities. 5.6 This test method is appropriate for temperatures within the range of 18 °C to 22 °C. It is the user's responsibility to determine the validity of the test method at alternate temperatures. 5.7 This test method will determine the relative spread radii for droplets of 10 μL and 20 μL. It is the user's responsibility to determine the validity of the test method at alternate droplet sizes.