Evaluation of Closed-Loop Site-Specific Irrigation with Wireless Sensor Network

Automated site-specific sprinkler irrigation system can save water and maximize productivity, but implementing automated irrigation is challenging in system integration and decision making. A controllable irrigation system was integrated into a closed-loop control with a distributed wireless in-field sensor network for automated variable-rate irrigation. An experimental field was configured into five soil zones based on soil electrical conductivity. In-field soil water sensors were installed on each zone of the distributed wireless sensor network and remotely monitored by a base station for decision making. The soil water sensors were calibrated with a neutron probe and individually identified for their response ranges at each zone. Irrigation decisions were site-specifically made based on feedback of soil water conditions from distributed in-field sensor stations. Variable-rate water application was remotely controlled by the base station to actuate solenoids to regulate the amount of time an individual group of sprinkler nozzles was irrigating in a 60-s time period. The performance of the system was evaluated with the measurement of water usage and soil water status throughout the growing season. Variable water distribution collected in catch cans highly matched to the rate assigned by computer with r(2)=0.96. User-friendly software provided real-time wireless irrigation control and monitoring during the irrigation operation without interruptions in wireless radio communication.