Investigation of soil wetting pattern in drip irrigation using LoraWAN technology

Soil moisture based irrigation was used widely due to its low cost, effectiveness in saving water, and increasing of crop yield. However, soil moisture under drip irrigation varies spatially due to the influences of environmental factors. That means the location of soil moisture sensors can affect the soil moisture levels in a field. Thus, investigation of soil water movement to guide the placement of soil moisture sensors could be an important factor for well-designed soil moisture based irrigation system. To investigate the water movement under drip irrigation, an Internet of Things (IoT) system including soil water potential (SWP) sensors, LoRa (Long Range) communication system, local gateway, and cloud server was developed. 16 SWP sensors were placed in crop root zone at one side of an emitter along with the dripline. With the designed configuration, the data of SWP sensors could be monitored and accessed by end users through internet. The developed IoT system was tested and evaluated functionally, even there was no irrigation event during the period. The results indicated that The SWP sensors could detect the change of SWP and were sensitive enough to respond these changes during a precipitation event. The outcome from this study showed the effectiveness of the LoRaWAN based IoT system in the investigation of water movement in the soil. More experiment will be conducted to measure the soil water movement under drip irrigation in the future.