Examination and parameterization of the root water uptake model from stem water potential and sap flow measurements
Article first published online: 15 JUN 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Volume 27, Issue 20, pages 2857–2863, 30 September 2013
How to Cite
Yang, Y., Guan, H., Hutson, J. L., Wang, H., Ewenz, C., Shang, S. and Simmons, C. T. (2013), Examination and parameterization of the root water uptake model from stem water potential and sap flow measurements. Hydrol. Process., 27: 2857–2863. doi: 10.1002/hyp.9406
- Issue published online: 2 SEP 2013
- Article first published online: 15 JUN 2012
- Accepted manuscript online: 16 MAY 2012 06:02AM EST
- Manuscript Accepted: 11 MAY 2012
- Manuscript Received: 18 JAN 2012
- root water uptake;
- stem water potential;
- sap flow;
- drooping sheoak
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. The method is applied to two drooping sheoak (Allocasuarina verticillata) trees for a period of 80 days, covering both a dry season and a wet season. The results indicate that the S-shape function is more 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 soil moisture but also dependent of the atmospheric demand. As a result, the water stress function is corrected for the effect of atmospheric conditions. Copyright © 2012 John Wiley & Sons, Ltd.