Relationship of Wind Speed and Canopy Leaf Temperature Rise for Air Stirring Frost Protection in Tea Field

Abstract

Wind speed and leaf temperature under wind machine running were measured in frost nights. Hot-wire anemometers and thermometers were placed side by side on bush canopies in terms of distance 5.4 m, 10.8 m, 16.2 m, 21.6 m, 27.0 m points ahead of the wind machine. Wind speed showed a maximum at 10.8 m point closest to the wind machine, but changed smaller as distance. Leaf temperature rise showed a maximum at 5.4 m - 10.8 m points, but changed smaller as distance. Between 10.8 - 27.0 m points, leaf temperature rise seemed to increase as wind speed was large. Leaf temperature rise was greater amount despite wind speed is small at 5.4 m point. From these results, frost-protective effect of the air stirring method is dependent on the leaf temperature rise caused by the wind hits the tea bush canopy, but on another factor in the range close to the wind machine.