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A number of methods have been employed for measuring quantitatively and qualitatively the deposition of spray materials on crops. Most methods involve the placement of targets prior to spraying. Techniques de scribed by MacCarthy (4), Blodgett and Mader (1), were used to obtain precipitates of copper and zinc salts along with potato leaflet impressions on sensitized filter paper. Large numbers of these impressions used to assess sprayer performance (6) made an objective method of colour distribution assessment desirable. Initial trials with a Photovolt Reflectometer showed promise of distinguishable differences between areas of precipitates. The most applicable method described herein utilized the Hunter Colour and Colour Difference Meter (2). This study was concerned with establishing a suitable calibration curve for converting meter readings into percent coverage of spray material on potato leaflets.
assessment of spray coverages on leaves by light reflectance methods
Staley, L.M. 1965. ASSESSMENT OF SPRAY COVERAGES ON LEAVES BY LIGHT REFLECTANCE METHODS. Canadian Agricultural Engineering 7(1):20-21.