|Iversen, William - Bill|
Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/31/2008
Publication Date: 1/1/2009
Publication URL: hdl.handle.net/10113/34348
Citation: Kim, Y., Evans, R.G., Iversen, W.M. 2009. Evaluation of closed-loop site-specific irrigation with wireless sensor network. Journal of Irrigation and Drainage Engineering. 135(1): 25-31. Interpretive Summary: Irrigation is critical in a cropping system and efficient water management is required to maximize productivity and minimize environmental impact. A sensor-based irrigation system was developed to automate site-specific irrigation. Variable-rate water application was wirelessly controlled at a remote to operate individual group of sprinkler nozzles. Decision making for variable-rate irrigation was determined by feedback of in-field sensors that were distributed across the field and measured soil water conditions at each soil zone. Irrigation was site-specifically applied and actual water distribution accurately followed the rate planned by computer. The benefit of the closed-loop control for a site-specific irrigation system with wireless sensor network will extend to automation of agrochemical applications.
Technical Abstract: 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 sensors were installed on each zone of the distributed wireless sensor network and remotely monitored by a base station for decision making. 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-sec 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 r2=0.96.