Low-cost soil moisture profile probe [Student]

Paper Introduction


Soil moisture is an important property for agriculture, but currently commercialized soil moisture sensors are too expensive for many farmers.

The objective of this study is to develop a low-cost soil moisture sensor using capacitors on a film substrate and a capacitive touch integrated circuit. The performance of the sensor was evaluated in two field experiments: a grape field and a mizuna greenhouse field. The developed sensor captured dynamic changes in soil moisture at 10, 20, and 30 cm depth, with a period of 10–14 days required after sensor installation for the contact between capacitors and soil to settle down.

Figure 1: Soil Moisture Profile Probe.

The measured soil moisture showed the influence of individual sensor differences, and the influence masked minor differences of less than 0.05 m3·m−3 in the soil moisture at different locations. However, the developed sensor could detect large differences of more than 0.05 m3·m−3, as well as the different magnitude of changes, in soil moisture. The price of the developed sensor was reduced to 300 U.S. dollars and can be reduced even more by further improvements suggested in this study and by mass production.

Figure 2: Scheme of the network system with the developed soil moisture sensors.

Therefore, the developed sensor will be made more affordable to farmers as it requires low financial investment, and it can be utilized for decision-making in irrigation. [1]

Figure 3: Details for (a) master node and (b) slave node of the sensor network system.
Figure 4: Dimensions of the greenhouse and locations of master and slave nodes.

References


[1] Yuki Kojima,Ryo Shigeta, Naoya Miyamoto, Yasutomo Shirahama, Kazuhiro Nishioka, Masaru Mizoguchi and Yoshihiro Kawahara (2016) Low-Cost Soil Moisture Profile Probe Using Thin-Film Capacitors and a Capacitive Touch Sensor. Sensors 2016, 16(8), 1292; https://doi.org/10.3390/s16081292

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