Soil moisture monitors are automated observation instruments designed for long-term field deployment. Their core function is the simultaneous acquisition of data on soil volumetric water content, temperature, and electrical conductivity. Utilizing Frequency Domain Reflectometry (FDR) or Time Domain Reflectometry (TDR) principles, these devices measure changes in the soil's dielectric constant via stainless-steel probe pins, which are then converted into moisture content values. The tubular design integrates multiple measurement points within a single probe—spaced as closely as 10 centimeters apart—enabling the simultaneous collection of temperature, moisture, and electrical conductivity data across six soil layers. A single installation can cover the primary root zone of crops, significantly reducing the wiring requirements and soil disturbance associated with traditional multi-point sensor burial.
The power supply system features a solar panel integrated into the top cover, paired with an MPPT (Maximum Power Point Tracking) charge controller. This configuration enhances charging efficiency, ensuring continuous operation even in low-light field conditions. Data transmission options include wired, 4G, or Bluetooth connections, with the system capable of sending SMS alerts to designated mobile phones if monitored data exceeds preset thresholds. The soil moisture and temperature sensors are housed in an integrated unit; the stainless-steel pins are resistant to long-term electrolysis, and the protective enclosure—also made of stainless steel—boasts an IP66 waterproof rating, making it suitable for outdoor use in environments subject to rainfall or irrigation.
The installation process for these soil moisture monitors is straightforward, requiring no complex calibration and allowing a single person to complete the setup within 30 minutes. These devices are widely used in applications such as agricultural irrigation management, forestry ecological monitoring, and academic research on soil profiles. With optional expansions, they can also incorporate sensors for soil pH, air temperature and humidity, and rainfall, creating a multi-parameter observation node centered on soil moisture. The significance of six-layer simultaneous data acquisition lies in the ability to capture moisture and temperature profiles at various depths at the exact same moment. This provides a continuous record essential for determining the infiltration depth of irrigation water, identifying the soil layers from which roots extract water, and tracking changes in the soil's thermal state.
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