Wireless Sensor Network for Monitoring Soil Moisture and Weather Conditions

Abstract

Abstract. A wireless sensor network (WSN) was built and deployed in three fields to monitor soil moisture status and collect weather data for irrigation scheduling. The WSN consists of soil moisture sensors, weather sensors, wireless data loggers, and a wireless modem. Soil moisture sensors were installed at three depths below the ground surface in various locations across the fields. Weather sensors were mounted on a 3-m instrument tower. An antenna mount was designed and fabricated for use in the WSN. When field equipment such as a fertilizer or chemical applicator impacted the mount, the mount was capable of protecting the antenna from damage by the equipment. In the WSN, received radio signal strength of Em50R data logger decreased as the distance from the data logger to the receiver increased. It also decreased as the distance between the top of the plant canopy and the logger’s antenna above the plant canopy decreased. The antenna of the Em50R logger required replacement above the plant canopy for effective data communication. The Em50G data logger was capable of transferring data as its antenna was inside the plant canopy. Using the WSN system, soil moisture and weather conditions including precipitation, solar radiation, wind speed, and humidity were measured every minute and the hourly averages were reported and stored at 1-h interval. The soil moisture data and weather data were automatically and wirelessly transmitted to the internet making the data available online. Data collected by the WSN have been used in irrigation scheduling research in cotton, corn and soybean crops.