Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2010
Publication Date: 8/14/2011
Publication URL: http://handle.nal.usda.gov/10113/54421
Citation: Kim, Y., Jabro, J.D., Evans, R.G. 2011. Wireless lysimeters for real-time online soil water monitoring. Irrigation Science. 29(5):423-430.
Interpretive Summary: Identification of agrochemicals in leachate allows accessing the effectiveness of water quality management. Wireless lysimeters were designed and evaluated for real-time online monitoring using in-field wireless sensor network. Twelve lysimeters were installed across the field and equipped with two rain gauges to measure amount of drainage water and two soil moisture sensors installed above the lysimeter to continually monitor soil water contents. This design incorporated Bluetooth sensing technology to enable an automated datalogger to transmit drainage water and flux data continuously to a remote host. The host computer was bridged to a web server, and real-time online monitoring and seamless measuring of drainage water and fluxes was thus possible without the need for costly time-consuming supportive operations. This novel lysimeter design provided an accurate and convenient way to measure water drainage and flux in the vadose zone.
Technical Abstract: Identification of nitrate-nitrogen (NO3-N) in drainage water allows accessing the effectiveness of water quality management. A passive capillary wick-type lysimeter (PCAPs) was used to monitor water flux and NO3-N leached below the root zone under an irrigated cropping system. Wireless lysimeters were developed for web-based real-time online monitoring of drainage water by using a distributed wireless sensor network (WSN). Twelve PCAPs type sensing stations were installed across the field, and each station measured the amount of drainage water using two tipping buckets mounted in the lysimeter and continually monitored soil water contents using two soil moisture sensors installed above each lysimeter. The sensors were connected to a datalogger that was a stand alone and self-powered by a solar power. A weather station was included in the WSN to measure micrometeorological field conditions (i.e. air temperature, relative humidity, soil temperature, precipitation, wind speed, wind direction, and solar radiation). All in-field sensory data were periodically sampled and wirelessly transmitted to a base station that was bridged to a web server for broadcasting the data on the internet. Communication signals from the in-field sensing stations to the base station were successfully interfaced using low-cost Bluetooth wireless radio communication. Web-link offered stable remote access to field conditions and real-time monitoring of the lysimeters.