{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T08:36:17Z","timestamp":1772699777257,"version":"3.50.1"},"reference-count":21,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,2,1]],"date-time":"2021-02-01T00:00:00Z","timestamp":1612137600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003151","name":"Fonds de recherche du Qu\u00e9bec \u2013 Nature et technologies","doi-asserted-by":"publisher","award":["2015-NC-180817"],"award-info":[{"award-number":["2015-NC-180817"]}],"id":[{"id":"10.13039\/501100003151","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada","doi-asserted-by":"publisher","award":["RGPIN-2014-04100"],"award-info":[{"award-number":["RGPIN-2014-04100"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The actively heated fiber optics (AHFO) technique has the potential to measure soil water at high spatial and temporal resolutions, and thus it can bridge the measurement gap from point to large scales. However, the availability of power might restrict its use, since high power is required to heat long fiber optic cables under field conditions; this can be a challenge for long-term soil water monitoring under field conditions. This study investigated the performance of different heating strategies (power intensity and heating duration) on soil water measurement by the AHFO technique on three different textured soils. Different heating strategies: high power\u2013short pulses (20 Wm\u22121\u20133 min), low power\u2013short pulses (10 Wm\u22121\u20133 min, 5 Wm\u22121\u20133 min, 2.5 Wm\u22121\u20133 min) and low power\u2013long pulses (10 Wm\u22121\u20135 min, 5 Wm\u22121\u201310 min, 2.5 Wm\u22121\u201315 min) were tested using laboratory soil columns. The study compared the sensitivity of the thermal response, NTcum to volumetric water content (VWC) and the predictive error of different heating strategies and soils. Results of this study showed that the sensitivity of NTcum increased and the predictive error decreased with increasing power intensity, irrespective of the soil type. Low power\u2013short heat pulses such as 5 Wm\u22121\u20133 min and 2.5 Wm\u22121\u20133 min produced high predictive errors, RMSE of 5\u20136% and 6\u20137%, respectively. However, extending the heating duration was effective in reducing the error for both 10 and 5 Wm\u22121 power intensities, but not for the 2.5 Wm\u22121. The improvement was particularly noticeable in 5 Wm\u22121 \u201310 min; it reduced the RMSE by 1.5% (sand and clay loam) and 2.73% (sandy loam). Overall, the results of this study suggested that extending the heating duration of 10 and 5 Wm\u22121 power intensities can improve the sensitivity of the thermal response and predictive accuracy of the estimated soil water content (SWC). The results are particularly important for field applications of the AHFO technique, which can be limited by the availability of high power, which restricts the use of 20 Wm\u22121. For example, 5 Wm\u22121\u201310 min improved the predictive accuracy to 3\u20134%, which has the potential to be used for validating soil water estimations at satellite footprint scales. However, the effects of diurnal temperature variations should also be considered, particularly when using low power intensity such as 5 Wm\u22121 in surface soils under field conditions.<\/jats:p>","DOI":"10.3390\/s21030962","type":"journal-article","created":{"date-parts":[[2021,2,1]],"date-time":"2021-02-01T05:16:28Z","timestamp":1612156588000},"page":"962","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Comparison of Heating Strategies on Soil Water Measurement Using Actively Heated Fiber Optics on Contrasting Textured Soils"],"prefix":"10.3390","volume":"21","author":[{"given":"Duminda N.","family":"Vidana Gamage","sequence":"first","affiliation":[{"name":"Department of Natural Resources Sciences, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada"},{"name":"Department of Soil Science, University of Peradeniya, Peradeniya 20400, Sri Lanka"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiteshkumar B.","family":"Vasava","sequence":"additional","affiliation":[{"name":"School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ian B.","family":"Strachan","sequence":"additional","affiliation":[{"name":"Department of Natural Resources Sciences, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7279-3597","authenticated-orcid":false,"given":"Viacheslav I.","family":"Adamchuk","sequence":"additional","affiliation":[{"name":"Department of Bioresource Engineering, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0801-3546","authenticated-orcid":false,"given":"Asim","family":"Biswas","sequence":"additional","affiliation":[{"name":"School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"797","DOI":"10.1029\/1998WR900065","article-title":"Observed spatial organization of soil moisture and its relation to terrain indices","volume":"35","author":"Western","year":"1999","journal-title":"Water Resour. 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