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Marc W. Van Iersel, Sue Dove, Jong-Goo Kang, and Stephanie E. Burnett

to 2 d before visible symptoms occur ( Blom-Zandstra and Metselaar, 2006 ; Kacira et al., 2002 ). Drawbacks of using sensors to detect plant stress for irrigation control are that such methods do not indicate how much water should be applied and that

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Noah J. Langenfeld and Bruce Bugbee

cathode, and produces a voltage difference with the anode that is proportional to oxygen concentration ( Parra et al., 2018 ). There are two types of electrochemical technology. Polarographic sensors have a gold cathode and silver anode that are

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Azlan Zahid, Md Sultan Mahmud, Long He, James Schupp, Daeun Choi, and Paul Heinemann

performed with objectives: 1) to integrate force measurement and inertial measurement unit (IMU) sensors with a manual shear pruner to perform pruning dynamic tests; 2) to investigate pruning torque requirements for different apple cultivars; and 3) to

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Amanda Bayer, John Ruter, and Marc W. van Iersel

currently limited ( Warsaw et al., 2009 ). Understanding how plant growth is affected by maintenance of different θ thresholds will allow for species-specific guidelines. Automated irrigation using capacitance sensors to maintain θ thresholds can be used to

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Shuyang Zhen and Stephanie E. Burnett

irrigation efficiency is that it reduces water and fertilizer waste. In the previously mentioned research, plants that were irrigated when substrates were dry according to measurements from sensors received 83% less irrigation water than those that were

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William L. Bauerle and Joseph D. Bowden

This report describes a system for integrating photosynthetically active radiation (PAR) using fiberoptics. Many photoelectric sensors or 1-m-long line sensors that integrate individual interception points for spatial averaging were replaced with fiberoptics, which integrate interception points. Depending on the positioning of optical fibers and the amount of fibers terminated at a PAR sensor, whole-plant, canopy layer, and individual leaf light interception can be determined. The use of fiberoptics has the added advantage of being very small in comparison to the bulk of a typical quantum sensor. The fiberoptic-based system potentially is a more accurate, less expensive method to integrate PAR throughout plant canopies than PAR sensors.

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Michael D. Dukes, Lincoln Zotarelli, and Kelly T. Morgan

, 2008b , 2009 ). Because applying frequent small-volume irrigation with conventional systems tends to be labor-intensive and/or technically difficult to use, sensor-based irrigation systems may facilitate the successful use of low-volume, high

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Qamar Uz Zaman, Arnold Walter Schumann, and David Charles Percival

accurate than survey maps and DEM. However, these techniques are expensive and data processing is also intensive and complicated. Therefore, there is a need to develop a cost-effective system using reliable and inexpensive sensors for real-time measurement

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Sai Xu, Huazhong Lu, and Xiuxiu Sun

detection method ( Alves et al., 2011 ) and the physicochemical detection method ( Huang et al., 2016 ). The sensor detection method evaluates the qualities of litchi fruit such as the pericarp color, flavor, and fragrance based on multiple human perceptive

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Thomas A. Obreza and Arnold Schumann

receive any fertilizer. With VRT, fertilizer is applied on a tree-by-tree basis using automatic sensors to determine the rate according to tree height or canopy density ( Schumann et al., 2006 ). Fertilizer use in highly variable citrus groves has been