Applied Sciences (Sep 2018)

Comparison between Capacitive and Microstructured Optical Fiber Soil Moisture Sensors

  • Aitor Lopez Aldaba,
  • Diego Lopez-Torres,
  • Miguel A. Campo-Bescós,
  • José Javier López,
  • David Yerro,
  • César Elosua,
  • Francisco J. Arregui,
  • Jean-Louis Auguste,
  • Raphael Jamier,
  • Philippe Roy,
  • Manuel López-Amo

DOI
https://doi.org/10.3390/app8091499
Journal volume & issue
Vol. 8, no. 9
p. 1499

Abstract

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Soil moisture content has always been an important parameter to control because it is a deterministic factor for site-specific irrigation, seeding, transplanting, and compaction detection. In this work, a discrete sensor that is based on a SnO2–FP (Fabry-Pérot) cavity is presented and characterized in real soil conditions. As far as authors know, it is the first time that a microstructured optical fiber is used for real soil moisture measurements. Its performance is compared with a commercial capacitive soil moisture sensor in two different soil scenarios for two weeks. The optical sensor shows a great agreement with capacitive sensor’s response and gravimetric measurements, as well as a fast and reversible response; moreover, the interrogation technique allows for several sensors to be potentially multiplexed, which offers the possibility of local measurements instead of volumetric: it constitutes a great tool for real soil moisture monitoring.

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