Soil sensor and soil measurement method

A soil measurement method, comprising:

• a step of arranging an electrode unit, which is connected to a current supply unit that outputs a DC current, in soil as a measurement target and then supplying the DC current to the measurement target through the electrode unit;
• and
• a step of obtaining a water content and a total ion concentration in the measurement target using a temporal change of a measured voltage, which is generated in the electrode unit, while the DC current is being supplied to the measurement target,
• wherein the step of obtaining the water content and the total ion concentration includes:
• a step of converting time information from when the current supply unit starts supplying the DC current to when an absolute value of the measured voltage reaches an absolute value of a threshold voltage into frequency information by determining whether or not the absolute value of the measured voltage has reached the absolute value of the threshold voltage using the temporal change of the measured voltage;
• a step of obtaining an impedance of the measurement target using the frequency information, the threshold voltage, and the DC current;
• a step of obtaining the water content using the impedance;
• and
• a step of obtaining the total ion concentration using the impedance.

A soil sensor, comprising:

• a first sensor unit that is disposed in soil as a measurement target and outputs a first measured voltage corresponding to a water content and a total ion concentration in the soil;
• a second sensor unit that is disposed in soil as the measurement target and outputs a second measured voltage corresponding to a temperature of the soil;
• an information conversion unit that is selectively connected to the first sensor unit and the second sensor unit and that converts the first measured voltage into first frequency information and converts the second measured voltage into second frequency information;
• and
• a measurement value calculation unit that is connected to the information conversion unit and that obtains the water content and the total ion concentration using the first frequency information and obtains the temperature using the second frequency information.