Because the global shortage of water is expected, saving water of the agriculture water is necessary. Because the global shortage of water is expected, saving water of the agriculture water is necessary. However, effective saving water is not able to be performed, because the water distribution in soil is difficult to grasp. Therefore, we propose a method of monitoring and imaging of the water content in the rooting zone using a sound vibration.
This time, we study about stable calculation method of propagation velocity in the soil and the soil water measurement during plant cultivation using the sound wave vibration. By a combination of two techniques, the cross-correlation function and the integrated squared amplitude method, improvement of the estimated precision of the propagation speed was examined. As the experimental results, we confirmed that the estimated precision of the propagation velocity became less than 1m/s in the purified soil. As a result of the measurement in the soil which a plant cultivated, it was really confirmed that a propagation velocity of sound in the soil is changing in response to a change of the volume water content and the matric potential. It became clear from this result for the water distribution in the rooting zone to be estimated with the propagation velocity of sound in soil.