Assessing rooting depths of an austrian pine stand by inverse modeling soil water content maps

• Published in: Water resources research 1999-10, Vol.35 (10), p.3041-3048
• Main Authors: Musters, P. A. D., Bouten, W.
• Format: Article
• Language: English
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1029/1999WR900173

Rooting depths in a forested stand (0.11 ha) were estimated indirectly by inverse modeling maps of soil water contents from time domain reflectometry (TDR) measurements at 150 points. These maps were described with a calibrated one‐dimensional soil water flow model, with specific values for the rooting depth, van Genuchten's [1980] α parameter, and throughfall fraction at each point. At about one third of the 150 points, modeled rooting depths did not fall within the a priori likely range of rooting depths; these values were discarded when kriging the point estimates to a map of rooting depths. The resulting rooting depths range from 0.8 m to 3.5 m within the stand in good agreement with root observations (R2 = 0.85). Several factors contributed positively to this good match, such as the fairly uniform soil hydraulic properties and the high sensitivity of soil water dynamics to root water uptake. Overall, the results demonstrate the suitability of soil water content maps based on TDR measurements to quantify spatial variability in soil water dynamics.