Detecting cavitation signals based on Ultrasonic acoustic emissions technology

This paper presents the experimental analysis on the relationship between Ultrasoinc acoustic emissions (UAEs) and water consumption associated with transpiration. In order to avoid background noise interference, the UAEs detecting frequency is between 100 KHz and 1 MHz. From the experiments, the hypothesis can be drawn that irrigation conducts when the UAEs reach a certain threshold, which may be beneficial to plant growth. Suffering a serious water deficit, the excessive transpiration cannot well recover, so there are some UAEs occuring in the night and next morning to lead to the physiological activities ahead of time. An ultrasonic acoustic emission event indicates the fracture of water columns in conduits, the several UAEs hits indicate the several elastic deformations of conduits in the process of energy release. The signal strength can not only reflect the acoustic emission event, but also reflect the signal energy, which indicates the transpiration pull force and tomato plant water status. It is better to use UAEs technique to diagnose the plant water status and carry out automatic and precise irrigation for the plant and to improve the effect of water-saving irrigation.