TY  - JOUR
AU  - Khare, Deepanshu
AU  - Selzner, Tobias
AU  - Leitner, Daniel
AU  - Vanderborght, Jan
AU  - Vereecken, Harry
AU  - Schnepf, Andrea
TI  - Root System Scale Models Significantly Overestimate Root Water Uptake at Drying Soil Conditions
JO  - Frontiers in Functional Plant Ecology
VL  - 13
SN  - 1664-462X
CY  - Lausanne
PB  - Frontiers Media
M1  - FZJ-2022-02590
SP  - 798741
PY  - 2022
AB  - Soil hydraulic conductivity (ksoil) drops significantly in dry soils, resulting in steep soil water potential gradients (ψs) near plant roots during water uptake. Coarse soil grid resolutions in root system scale (RSS) models of root water uptake (RWU) generally do not spatially resolve this gradient in drying soils which can lead to a large overestimation of RWU. To quantify this, we consider a benchmark scenario of RWU from drying soil for which a numerical reference solution is available. We analyze this problem using a finite volume scheme and investigate the impact of grid size on the RSS model results. At dry conditions, the cumulative RWU was overestimated by up to 300% for the coarsest soil grid of 4.0 cm and by 30% for the finest soil grid of 0.2 cm, while the computational demand increased from 19 s to 21 h. As an accurate and computationally efficient alternative to the RSS model, we implemented a continuum multi-scale model where we keep a coarse grid resolution for the bulk soil, but in addition, we solve a 1-dimensional radially symmetric soil model at rhizosphere scale around individual root segments. The models at the two scales are coupled in a mass-conservative way. The multi-scale model compares best to the reference solution (−20%) at much lower computational costs of 4min. Our results demonstrate the need to shift to improved RWU models when simulating dry soil conditions and highlight that results for dry conditions obtained with RSS models of RWU should be interpreted with caution.
LB  - PUB:(DE-HGF)16
C6  - pmid:35237283
UR  - <Go to ISI:>//WOS:000761659600001
DO  - DOI:10.3389/fpls.2022.798741
UR  - https://juser.fz-juelich.de/record/908400
ER  -