Evaluation of the Heat Pulse Ratio Method for Measuring Soil Water Flux

dc.contributor.author Ochsner, Tyson
dc.contributor.author Horton, Robert
dc.contributor.author Horton, Robert
dc.contributor.author Kluitenberg, Gerald
dc.contributor.author Wang, Quanjiu
dc.contributor.department Agronomy
dc.date 2018-01-25T07:45:39.000
dc.date.accessioned 2020-06-29T23:04:39Z
dc.date.available 2020-06-29T23:04:39Z
dc.date.issued 2005-01-01
dc.description.abstract <p>Soil water flux is an important hydrologic parameter, yet few techniques for measuring it in situ are available. Here we evaluate the heat pulse ratio method for measuring water flux. We conducted heat pulse measurements of flux in packed columns of sand, sandy loam, and silt loam soil. Water fluxes were calculated from the data following both a traditional temperature increase difference method and a new temperature increase ratio method. Both methods yielded similar estimates of flux, agreeing to within 0.84 cm h<sup>−1</sup> on average. The low flow detection limits for both methods were also similar and ranged from 0.1 to 0.4 cm h<sup>−1</sup>However, the ratio method was superior in that it permitted simpler calculations, reduced the number of required parameters by four, and exhibited two to three times greater precision. We found strong linear relationships (<em>r</em> <sup>2</sup> ≥ 0.98, standard error < 0.4 cm h<sup>−1</sup>) between estimated and imposed water fluxes up to 40 cm h<sup>−1</sup> However, the slopes of these relationships were less than one, ranging from 0.739 for the sand to 0.224 for the sandy loam. These slopes indicate that the sensitivity was less than predicted by the standard conduction–convection model. We have not discovered the cause of these errors, but we did find that the errors could not be explained by increasing the magnitude of the conduction term in the model as has been previously suggested. Instead, the errors could be explained by reducing the magnitude of the convection term. This finding can help direct future research efforts to improve the accuracy of the ratio method.</p>
dc.description.comments <p>This article is published as Ochsner, Tyson E., Robert Horton, Gerard J. Kluitenberg, and Quanjiu Wang. "Evaluation of the heat pulse ratio method for measuring soil water flux." Soil Science Society of America Journal 69, no. 3 (2005): 757-765. doi: <a href="http://dx.doi.org/10.2136" target="_blank">10.2136/sssaj2004.0278</a>. Posted with permission.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/agron_pubs/369/
dc.identifier.articleid 1370
dc.identifier.contextkey 11389597
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath agron_pubs/369
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/4719
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/agron_pubs/369/2005_Horton_EvaluationHeat.pdf|||Fri Jan 14 23:48:41 UTC 2022
dc.source.uri 10.2136/sssaj2004.0278
dc.subject.disciplines Agriculture
dc.subject.disciplines Hydrology
dc.subject.disciplines Soil Science
dc.subject.disciplines Statistical Models
dc.title Evaluation of the Heat Pulse Ratio Method for Measuring Soil Water Flux
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication d3fb0917-6868-417e-9695-a010896cfafa
relation.isOrgUnitOfPublication fdd5c06c-bdbe-469c-a38e-51e664fece7a
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