A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach

By V. Couvreur, J. Vanderborght, Mathieu Javaux. 2012

201 citations recorded by the source corpus.

Many hydrological models including root water uptake (RWU) do not consider the dimension of root system hydraulic architecture (HA) because explicitly solving water flow in such a complex system is too time consuming. However, they might lack process understanding when basing RWU and plant water stress predictions on functions of variables such as the root length density distribution. On the basis of analytical solutions of water flow in a simple HA, we developed an “implicit” model of the root system HA for simulation of RWU distribution (sink term of Richards’ equation) and plant water stress in three-dimensional soil water flow models. The new model has three macroscopic parameters defined at the soil element scale, or at the plant scale, rather than for each segment of the root system architecture: the standard sink fraction distribution SSF, the root system equivalent conductanceKrs and the compensatory RWUconductance Kcomp. It clearly decouples the process of water stress from compensatory RWU, and its structure is appropriate for hydraulic lift simulation. As compared to a model explicitly solving water flow in a realistic maize root system HA, the implicit model showed to be accurate for predicting RWU distribution and plant collar water potential, with one single set of parameters, in dissimilar water dynamics scenarios. For these scenarios, the computing time of the implicit model was a factor 28 to 214 shorter than that of the explicit one.We also provide a new expression for the effective soil water potential sensed by plants in soils with a heterogeneous water potential distribution, which emerged from the implicit model equations. With the proposed implicit model of the root system HA, new concepts are brought which open avenues towards simple and mechanistic RWU models and water stress functions operational for field scale water dynamics simulation.

Subfields: Civil and Structural Engineering, Plant Science, Soil Science

View Paper: https://www.semanticscholar.org/paper/ac6bba2ca44bd7f91c3aab7a1768cfa85b179ee8

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Citations in the corpus

Implementation and Application of a Root Growth Module in HYDRUS (2018, methodology): “…complex, three-dimensional root architecture models (Clausnitzer and Hopmans, 1994; Somma et al., 1998; Leitner et al., 2010; Bingham and Wu, 2011; Couvreur et al., 2012) or simpler root growth models that are implemented within more complex models such as EPIC (Williams et al., 1989) or CERES…”
Root Water Uptake: From Three‐Dimensional Biophysical Processes to Macroscopic Modeling Approaches (2013, unknown): “Recently, Couvreur et al. (2012) reformulated this approach to extract a simple macroscopic stress function and a sink term distribution function, which predict the distribution of the water uptake and the reduction of the transpiration under water stress. heir model is thus a solution of the Ohm…”
Modeling Soil Processes: Review, Key Challenges, and New Perspectives (2016, background): “Couvreur et al. (2012) developed a simple one-dimensional solution, considering complex three-dimensional representations of root architecture.”
Compensatory uptake functions in empirical macroscopic root water uptake models: experimental and numerical analysis (2015, methodology): “…721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 58 59 interesting approach to RWU simulation would be to extrapolate the propositions of Couvreur et al. (2012) and Javaux et al. (2013) for the modeling of empirical macroscopic RWU models.”