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http://dx.doi.org/10.12791/KSBEC.2014.23.2.158

Measuring Water Content Characteristics by Using Frequency Domain Reflectometry Sensor in Coconut Coir Substrate  

Park, Sung Tae (Department of Environmental Horticulture, The university of Seoul Seoul)
Jung, Geum Hyang (Technology Service Division, National Institure of Horticultural & Herbal Science)
Yoo, Hyung Joo (Department of Environmental Horticulture, The university of Seoul Seoul)
Choi, Eun-Young (Department of Green Technology Convergence, KonKuk University)
Choi, Ki-Young (Department of Controlled Agriculture, Kangwon National University)
Lee, Yong-Beom (Department of Environmental Horticulture, The university of Seoul Seoul)
Publication Information
Journal of Bio-Environment Control / v.23, no.2, 2014 , pp. 158-166 More about this Journal
Abstract
This experiment has investigated suitable methods to improve precision water content monitoring of coconut coir substrates to control irrigation by frequency domain reflectometry(FDR) sensors. Specifically, water content changes and variations were observed at different sensing distances and positions from the irrigation dripper location, and different spaces between the FDR sensors with or without noise filters. Commercial coconut coir substrates containing different ratios of dust and chips(10:0, 7:3, 5:5, 3:7) were used. On the upper side and the side of the substrates, a FDR sensor was used at 5, 10, 20, 30cm distances respectively from the irrigation dripper point, and water content was measured by time after the irrigation. In the glass beads, sensors were installed with or without noise filtering. Closer sensing distance had a higher water content increasing rate, regardless of different coir substrate ratios. There were no differencies of water content increasing rates in 10:0 and 3:7 substrates between the upper side and the side. Whereas, 7:3 and 5:5 substrates showed higher increasing rates on the upper side measurements. Substrates with higher ratios of chip(3:7) had lower increasing rates than others. And, with noise filters, the exatitude of measurement was improved because the variation and deviation were reduced. Therefore, in coconut coir with FDR sensors, an efficient water content measurment to control irrigations can be achieved by installing sensors closer to an irrigation point and upper side of substrates with noise filters.
Keywords
growing medium; water sensor; sensor measurement position; sensor measurement distance;
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Times Cited By KSCI : 13  (Citation Analysis)
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