Evaluation of the utility of the Bikerman method for determining leaf wetting angles

Abstract

The physico-chemical properties of the spray liquid affect the efficiency and effectiveness of crop protection treatments. A measure of leaf wettability is the wetting angle, the testing of which is neglected in routinely performed spraying. In the search for a method useful for determining leaf wetting angle for crop protection treatments, the method that Bikerman (1941) applied to the surface of the object observed from above was evaluated. The assumptions of the method and the resulting opportunities and constraints in its application are presented in this paper. The influence of leaf, liquid and droplet properties on the wetting angle was discussed. It was concluded that Bikerman’s method is suitable for determining leaf wetting angles over a wide range of physical properties of liquids used in crop protection treatments.