Soil moisture sensor has FDR type and TDR type

At present, the commonly used soil moisture sensors are FDR type (frequency domain type) and TDR type (time domain type).

    The TDR method is a soil moisture measurement method developed in the 1980s. TDR is a system similar to a radar system, with strong independence, and its results are basically independent of soil type, density and temperature. And, importantly, TDR can measure soil moisture under freezing, which is unmatched by other methods. In addition, TDR can monitor soil water and salt content at the same time, and there is almost no difference between the results of the two measurements before and after.

    A simpler method than TDR to measure the dielectric constant of soil - FDR type (frequency domain type), which uses the principle of electromagnetic pulse to measure the apparent dielectric constant (ε) of soil according to the propagation frequency of electromagnetic waves in the medium , so as to obtain the soil volumetric water content (θv).

    FDR is not only cheaper than TDR, but also has a shorter measurement time. After a specific soil calibration, the measurement accuracy is high, and the shape of the probe is not limited. It can measure at multiple depths at the same time, and data acquisition is easier to achieve.

    FDR has the advantages of simple and safe, fast and accurate, continuous fixed point, automation, wide range, less calibration, etc. It is a recommended soil moisture measurement instrument.

    Most soil moisture sensors on the market use the FDR method to measure soil moisture. By measuring the dielectric constant of the soil, the volume percentage of soil moisture can be measured. The soil moisture measurement method conforms to the current international standards and can directly and stably reflect the true nature of various soils. moisture content.

    The soil moisture sensor is suitable for soil moisture monitoring, scientific experiments, water-saving irrigation, greenhouses, grasslands, pastures, soil rapid testing, plant cultivation, greenhouse control, precision agriculture, etc., as well as the measurement of water conservancy, meteorology and various particulate matter water content.