SENSING DURATION OF LEAF MOISTURE RETENTION USING ELECTRICAL IMPEDANCE GRIDS

Abstract

The duration of moisture retention on mock leaf sensors made from electrical impedance grids was purposely manipulated by changing the color and angle of deployment of these sensors. The duration of moisture retention varied up to 2 h 50 min, depending on the type of moisture deposited (rain or dew) and the conditions during drying. Comparisons were made with onion (Allium cepa L.) foliage where a very light gray mock leaf indicated complete drying of the crop with a maximum error of 27 min while a DeWit Leafwet Recorder had a maximum error of 90 min. A simple AC-powered circuit for recording leaf wetness is described. Also, for use in remote locations, a battery-powered system was constructed that utilized integrated circuits for low power consumption.