Monitoring spatial variability of soil moisture in an orchard using an LoRa-enabled IoT sensor technology

IoT (Internet of Things)-based sensor monitoring systems have been utilized in agriculture in many ways to help farmers make better-informed decisions in crop production. IoT sensors in agriculture have and will play a significant role in mitigating the effect of the recent extreme weather conditions, including increased temperature and heavy and erratic precipitation. This paper focuses on the evaluation of the variability of soil moisture in a farm using an IoT-based sensor monitoring system. Microcontrollers and LoRa were used to connect with Soil Watch 10 soil moisture sensors. LoRa gateway at this farm was able to reach a node that was 762 meters away. A total of 9 IoT-based sensor systems were installed on a farm. Soil moisture sensors were installed at 15, 30, and 60 cm soil depth. The collected soil moisture sensor data were used to calculate the median and mean relative deviation. At 15, 30, and 60-cm soil depths, there were 3, 5, and 3 locations within +/- 10 mean relative differences. Of those, one location was designated as the most representative site for soil depths of 15, 30, and 60 cm.