Water distribution measurement in soil using sound vibration

et al. 2015

Acoust. Sci. & Tech.

Self Cite

In order to estimate the water stress of a plant, the natural frequency of the leaf-stalk system was investigated. As a means of vibrating the leaf, acoustic radiation force was utilized, and the successive measurement of the natural frequency of ''komatsuna'', which was cultivated in a pot of soil, was performed for a week until wilting after stopping irrigation. As a result, it was found that the natural frequency is decreased drastically by the wilting of the leaf before the drooping occurs. In addition, daily variation was also observed in the early days, but it was gradually suppressed as the day went on. These behaviors were discussed referring to a simple cantilever beam model. In conclusion, it was ascertained that the acoustic radiation force is efficient for vibrating a leaf-stalk system. Furthermore, it was confirmed that measuring the natural frequency of the leaf-stalk system is effective for the early detection of water stress of a plant.

Section: Introductionmentioning

confidence: 99%

Estimation of water stress of plant by vibration measurement of leaf using acoustic radiation force

Sano

Nakagawa

et al. 2015

Acoust. Sci. & Tech.

Self Cite

“…Therefore, we propose a method for the monitoring and imaging of the water content in the rooting zone of plants using sound vibration. 1) Shallow underground imaging using the sound wave vibration has been already performed, and there are techniques using a shear horizontal wave, [2][3][4][5][6][7][8][9][10] an electromagnetic sound source, [11][12][13][14] a giant magnetostriction vibrator, [15][16][17] and an air-borne wave [18][19][20][21][22] have been developed. However, no research in which irrigation is controlled by measuring the water distribution in the rooting zone of plants using sound vibration has been performed yet.…”

Section: Introductionmentioning

confidence: 99%

Study on Water Distribution Imaging in the Sand Using Propagation Velocity of Sound with Scanning Laser Doppler Vibrometer

Nakagawa

Sügimura

et al. 2013

Jpn. J. Appl. Phys.

Self Cite

We propose a method for the monitoring and imaging of the water distribution in the rooting zone of plants using sound vibration. In this study, the water distribution measurement in the horizontal and vertical directions in the soil layer was examined to confirm whether a temporal change in the volume water content of the soil could be estimated from a temporal changes in propagation velocity. A scanning laser Doppler vibrometer (SLDV) is used for measurement of the vibration velocity of the soil surface, because the highly precise vibration velocity measurement of several many points can be carried out automatically. Sand with a uniform particle size distribution is used for the soil, as it has high plasticity; that is, the sand can return to a dry state easily even if it is soaked with water. A giant magnetostriction vibrator or a flat speaker is used as a sound source. Also, a soil moisture sensor, which measures the water content of the soil using the electric permittivity, is installed in the sand. From the experimental results of the vibration measurement and soil moisture sensors, we can confirm that the temporal changes of the water distribution in sand using the negative pressure irrigation system in both the horizontal and vertical directions can be estimated using the propagation velocity of sound. Therefore, in the future, we plan to develop an insertion-type sound source and receiver using the acceleration sensors, and we intend to examine whether our method can be applied even in commercial soil with growing plants.

“…Meanwhile, we have also been trying to visualize the water distribution in the soil by measuring the sound velocity through soil. 15,16) The sound velocity was measured for every point of a two-dimensional lattice on the soil surface by scanning with a scanning laser Doppler vibrometer (SLDV). [17][18][19] By using these two acoustic techniques of estimating the water stress of the plant and the water distribution in the soil, we will realize the precise control of irrigation for water-saving.…”

Section: Introductionmentioning

confidence: 99%

Basic Study on Estimating Water Stress of a Plant Using Vibration Measurement of Leaf

Sano

Hosoya

et al. 2013

Jpn. J. Appl. Phys.

Self Cite

A new noninvasive method for estimating the water stress of a plant was proposed. In order to investigate this method, we first examined the characteristic frequency of an individual leaf picked from the plant, and obtained the result that its characteristic frequency decreased in proportion to the reduction in the water content of the leaf. Next, we applied this method to a leaf on a branch and confirmed the same tendency when the water stress was increased by stopping the water supply of a plant cultured in water. From these results, it was suggested that the water stress of the plant could be estimated from the vibration measurement of the leaf. Lastly, the relationship between the water potential of the leaf and its elastic constant was discussed with the soil-plant-atmosphere-continuum model (SPAC model), and Young's modulus of a tomato leaf was roughly estimated.