Detection of Cavitation in Stem of Miniature Tomato using Acceleration Sensor

抄録

Cavitation (expansion of air bubbles) often occurs in xylem elements and blocks water transportation. Such a cavitation can be detected by an AE sensor attached to a stem because it generates acoustic emissions. Reducing the cost of the sensor, however, is a significant problem for the practical use of AE techniques in agriculture. In this study, we tried to detect AE owing to cavitation in the stems of plants using a low-cost acceleration sensor (ACC sensor) instead of a conventional AE sensor. Artificial AEs traveling a bar of balsa wood were measured using a conventional AE sensor and a wideband ACC sensor to compare the sensitivity. Then, the AE measurement of a miniature tomato was conducted using both sensors. The peak frequency of the signals detected by the ACC sensor while measuring an artificial AE was much lower than that of the AE sensor, although the signals detected by the AE sensor were reflected by the vibration of the actuator. The AE waveforms detected by the ACC sensor were also deeply related to the resonance frequency of the sensor. The AE occurrence rate of the ACC sensor, however, was similar to that of the AE sensor when the ACC sensor was attached to the stem of the plant by a hose clamp.