Examination and parameterization of the root water uptake model from stem water potential and sap flow measurements

Yuting Yang, Huade Guan, John L Hutson, Hailong Wang, Caecilia Ewenz, Songhao Shang, Craig T Simmons

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24 Citations (Scopus)

Abstract

A simple field-based method for directly parameterizing root water uptake models is proposed. Stem psychrometers and sap flow meters are used to measure stem water potential and plant transpiration rate continuously and simultaneously. Predawn stem water potential is selected as a surrogate for root zone soil water potential to examine and parameterize the root water uptake–water stress response functions. Themethod is applied to two drooping sheoak (Allocasuarina verticillata) trees for a period of 80 days, covering both a dry season and awet season. The results indicate that the S-shape function ismore appropriate than the Feddes piecewise linear function for drooping sheoak to represent the effect of soil moisture stress on its root water uptake performance. Besides, the water stress function is found to be not only a function of soilmoisture but also dependent of the atmospheric demand.As a result, thewater stress function is corrected for the effect of atmospheric conditions
Original languageEnglish
Pages (from-to)2857-2863
Number of pages7
JournalHydrological Processes
Volume27
Issue number20
Early online date15 Jun 2012
DOIs
Publication statusPublished - 30 Sep 2013

Keywords

  • root water uptake
  • stem water potential
  • sap flow
  • parameterization
  • drooping sheoak

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    Yang, Y., Guan, H., Hutson, J. L., Wang, H., Ewenz, C., Shang, S., & Simmons, C. T. (2013). Examination and parameterization of the root water uptake model from stem water potential and sap flow measurements. Hydrological Processes, 27(20), 2857-2863. https://doi.org/10.1002/hyp.9406