scholarly journals Call for participation: Collaborative benchmarking of functional-structural root architecture models. The case of root water uptake

2019 ◽  
Author(s):  
Andrea Schnepf ◽  
Christopher K. Black ◽  
Valentin Couvreur ◽  
Benjamin M. Delory ◽  
Claude Doussan ◽  
...  
Keyword(s):  
Root Growth ◽  
Water Flow ◽  
Root Architecture ◽  
Numerical Models ◽  
Model Development ◽  
Three Dimensional ◽  
Root Traits ◽  
Root Water Uptake ◽  
Sink Term ◽  
Engineering Sciences

AbstractThree-dimensional models of root growth, architecture and function are becoming important tools that aid the design of agricultural management schemes and the selection of beneficial root traits. However, while benchmarking is common in many disciplines that use numerical models such as natural and engineering sciences, functional-structural root architecture models have never been systematically compared. The following reasons might induce disagreement between the simulation results of different models: different representation of root growth, sink term of root water and solute uptake and representation of the rhizosphere. Presently, the extent of discrepancies is unknown, and a framework for quantitatively comparing functional-structural root architecture models is required. We propose, in a first step, to define benchmarking scenarios that test individual components of complex models: root architecture, water flow in soil and water flow in roots. While the latter two will focus mainly on comparing numerical aspects, the root architectural models have to be compared at a conceptual level as they generally differ in process representation. Therefore defining common inputs that allow recreating reference root systems in all models will be a key challenge. In a second step, benchmarking scenarios for the coupled problems are defined. We expect that the results of step 1 will enable us to better interpret differences found in step 2. This benchmarking will result in a better understanding of the different models and contribute towards improving them. Improved models will allow us to simulate various scenarios with greater confidence and avoid bugs, numerical errors or conceptual misunderstandings. This work will set a standard for future model development.

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

2012 ◽  
Vol 16 (8) ◽  
pp. 2957-2971 ◽  
Author(s):  
V. Couvreur ◽  
J. Vanderborght ◽  
M. Javaux
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Root System ◽  
Water Flow ◽  
Three Dimensional ◽  
Root Water Uptake ◽  
Water Dynamics ◽  
Hydraulic Architecture ◽  
Plant Water Stress ◽  
Implicit Model

Abstract. 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 conductance Krs and the compensatory RWU conductance 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.

scholarly journals An Integrated Graphic Modeling System for Three-Dimensional Hydrodynamic and Water Quality Simulation in Lakes

2019 ◽  
Vol 8 (1) ◽  
pp. 18 ◽  
Author(s):  
Mutao Huang ◽  
Yong Tian
Keyword(s):  
Water Quality ◽  
Numerical Models ◽  
Model Development ◽  
Three Dimensional ◽  
Water Quality Modeling ◽  
Transport Processes ◽  
Water Diversion ◽  
Water Quality Simulation ◽  
Graphic Modeling ◽  
Output Information

Understanding the complex hydrodynamics and transport processes are of primary importance to alleviate and control the eutrophication problem in lakes. Numerical models are used to simulate these processes. However, it is often difficult to perform such a numerical modeling simulation for common users. This study presented an integrated graphic modeling system designed for three-dimensional hydrodynamic and water quality simulation in lakes. The system, called the Lake Modeling System (LMS), provides necessary functionalities streamlined for hydrodynamic modeling. The LMS provides a geographic information system (GIS)-based data processing framework to establish a model and provides capabilities for displaying model input and output information. The LMS also provides mapping and visualization tools to support the model development process. All of these features in a GIS-based framework makes the task of complex hydrodynamic and water quality modeling easier. The applicability of the LMS is demonstrated by a case study in Lake Donghu, which is a large urban lake in the middle reaches of the Yangtze River in China. The LMS was utilized to setup and calibrate a model for Lake Donghu. Then the model was used to study the effects of a water diversion project on the change in hydrodynamics and the water quality.

scholarly journals Numerical and physical modeling of water flow over the ogee weir of the new Niedów barrage

2016 ◽  
Vol 64 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Oscar Herrera-Granados ◽  
Stanisław W. Kostecki
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Steady Flow ◽  
Water Flow ◽  
Physical Modeling ◽  
Numerical Models ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Flow Conditions ◽  
Low Head

Abstract In this paper, two- and three-dimensional numerical modeling is applied in order to simulate water flow behavior over the new Niedów barrage in South Poland. The draining capacity of one of the flood alleviation structures (ogee weir) for exploitation and catastrophic conditions was estimated. In addition, the output of the numerical models is compared with experimental data. The experiments demonstrated that the draining capacity of the barrage alleviation scheme is sufficiently designed for catastrophic scenarios if water is flowing under steady flow conditions. Nevertheless, the new cofferdam, which is part of the temporal reconstruction works, is affecting the draining capacity of the whole low-head barrage project.

scholarly journals From hydraulic root architecture models to macroscopic representations of root hydraulics in soil water flow and land surface models

2021 ◽  
Author(s):  
Jan Vanderborght ◽  
Valentin Couvreur ◽  
Felicien Meunier ◽  
Andrea Schnepf ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Flow ◽  
Water Uptake ◽  
Land Surface ◽  
Root Architecture ◽  
Root Water Uptake ◽  
Land Surface Models ◽  
Surface Models ◽  
Root Model ◽  
Soil Water Flow

Abstract. Root water uptake is an important process in the terrestrial water cycle. How this process depends on soil water content, root distributions, and root properties is a soil-root hydraulic problem. We compare different approaches to implement root hydraulics in macroscopic soil water flow and land surface models. By upscaling a three dimensional hydraulic root architecture model, we derived an exact macroscopic root hydraulic model. The macroscopic model uses three characteristics: the root system conductance, Krs, the standard uptake fraction, SUF, that represents the uptake from a soil profile with a uniform hydraulic head, and a compensatory matrix that describes the redistribution of water uptake in a non-uniform hydraulic head profile. Two characteristics, Krs and SUF, are sufficient to describe the total uptake as a function of the collar and soil water potential; and water uptake redistribution does not depend on the total uptake or collar water potential. We compared the exact model with two hydraulic root models that make a-priori simplifications of the hydraulic root architecture: the parallel and big root model. The parallel root model uses only two characteristics, Krs and SUF, that can be calculated directly following a bottom up approach from the 3D hydraulic root architecture. The big root model uses more parameters than the parallel root model but these parameters cannot be obtained straightforwardly with a bottom up approach. The big root model was parameterized using a top down approach, i.e. directly from root segment hydraulic properties assuming a-priori a single big root architecture. This simplification of the hydraulic root architecture led to less accurate descriptions of root water uptake than by the parallel root model. To compute root water uptake in macroscopic soil water flow and land surface models, we recommend the use of the parallel root model with Krs and SUF computed in a bottom up approach from a known 3D root hydraulic architecture.

scholarly journals From hydraulic root architecture models to macroscopic representations of root hydraulics in soil water flow and land surface models

2021 ◽  
Vol 25 (9) ◽  
pp. 4835-4860
Author(s):  
Jan Vanderborght ◽  
Valentin Couvreur ◽  
Felicien Meunier ◽  
Andrea Schnepf ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Flow ◽  
Water Uptake ◽  
Land Surface ◽  
Root Architecture ◽  
Root Water Uptake ◽  
Land Surface Models ◽  
Surface Models ◽  
Root Model ◽  
Soil Water Flow

Abstract. Root water uptake is an important process in the terrestrial water cycle. How this process depends on soil water content, root distributions, and root properties is a soil–root hydraulic problem. We compare different approaches to implement root hydraulics in macroscopic soil water flow and land surface models. By upscaling a three-dimensional hydraulic root architecture model, we derived an exact macroscopic root hydraulic model. The macroscopic model uses the following three characteristics: the root system conductance, Krs, the standard uptake fraction, SUF, which represents the uptake from a soil profile with a uniform hydraulic head, and a compensatory matrix that describes the redistribution of water uptake in a non-uniform hydraulic head profile. The two characteristics, Krs and SUF, are sufficient to describe the total uptake as a function of the collar and soil water potential, and water uptake redistribution does not depend on the total uptake or collar water potential. We compared the exact model with two hydraulic root models that make a priori simplifications of the hydraulic root architecture, i.e., the parallel and big root model. The parallel root model uses only two characteristics, Krs and SUF, which can be calculated directly following a bottom-up approach from the 3D hydraulic root architecture. The big root model uses more parameters than the parallel root model, but these parameters cannot be obtained straightforwardly with a bottom-up approach. The big root model was parameterized using a top-down approach, i.e., directly from root segment hydraulic properties, assuming a priori a single big root architecture. This simplification of the hydraulic root architecture led to less accurate descriptions of root water uptake than by the parallel root model. To compute root water uptake in macroscopic soil water flow and land surface models, we recommend the use of the parallel root model with Krs and SUF computed in a bottom-up approach from a known 3D root hydraulic architecture.

scholarly journals Implementing small scale processes at the soil-plant interface – the role of root architectures for calculating root water uptake profiles

2010 ◽  
Vol 14 (2) ◽  
pp. 279-289 ◽  
Author(s):  
C. L. Schneider ◽  
S. Attinger ◽  
J.-O. Delfs ◽  
A. Hildebrandt
Keyword(s):  
Soil Water ◽  
Water Flow ◽  
Water Uptake ◽  
Soil Water Potential ◽  
Root Systems ◽  
Root Water Uptake ◽  
Bulk Soil ◽  
Small Scale ◽  
Sink Term

Abstract. In this paper, we present a stand alone root water uptake model called aRoot, which calculates the sink term for any bulk soil water flow model taking into account water flow within and around a root network. The boundary conditions for the model are the atmospheric water demand and the bulk soil water content. The variable determining the plant regulation for water uptake is the soil water potential at the soil-root interface. In the current version, we present an implementation of aRoot coupled to a 3-D Richards model. The coupled model is applied to investigate the role of root architecture on the spatial distribution of root water uptake. For this, we modeled root water uptake for an ensemble (50 realizations) of root systems generated for the same species (one month old Sorghum). The investigation was divided into two Scenarios for aRoot, one with comparatively high (A) and one with low (B) root radial resistance. We compared the results of both aRoot Scenarios with root water uptake calculated using the traditional Feddes model. The vertical rooting density profiles of the generated root systems were similar. In contrast the vertical water uptake profiles differed considerably between individuals, and more so for Scenario B than A. Also, limitation of water uptake occurred at different bulk soil moisture for different modeled individuals, in particular for Scenario A. Moreover, the aRoot model simulations show a redistribution of water uptake from more densely to less densely rooted layers with time. This behavior is in agreement with observation, but was not reproduced by the Feddes model.

scholarly journals CRootBox: A structural-functional modelling framework for root systems

2017 ◽  
Author(s):  
Andrea Schnepf ◽  
Daniel Leitner ◽  
Magdalena Landl ◽  
Guillaume Lobet ◽  
Trung Hieu Mai ◽  
...  
Keyword(s):  
Water Flow ◽  
Web Application ◽  
Root Architecture ◽  
Root Systems ◽  
Root Water Uptake ◽  
Soil Conditions ◽  
Soil Physics ◽  
Architecture Model ◽  
Single Root ◽  
The Impact

ABSTRACTBackground and AimsRoot architecture development determines the sites in soil where roots provide input of carbon and take up water and solutes. However, root architecture is difficult to determine experimentally when grown in opaque soil. Thus, root architectural models have been widely used and been further developed into functional-structural models that simulate the fate of water and solutes in the soil-root system. We present a root architectural model, CRootBox, as a flexible framework to model architecture and its interactions with static and dynamic soil environments.MethodsCRootBox is a C++ -based root architecture model with Python binding, so that CRootBox can be included via a shared library into any Python code. Output formats include VTP, DGF, RSML and CSV. We further created a database of published root architectural parameters. The capabilities of CRootBox for the unconfined growth of single root systems, as well as the different parameter sets, are highlighted into a freely available web application.Key resultsWe demonstrate the use of CRootBox for 5 different cases (1) free growth of individual root systems (2) growth of root systems in containers as a way to mimic experimental setups, (3), field scale simulation, (4) root growth as affected by heterogeneous, static soil conditions, and (5) coupling CRootBox with Soil Physics with Python code to dynamically compute water flow in soil, root water uptake, and water flow inside roots.ConclusionsIn conclusion, we present a fast and flexible functional-structural root model which is based on state-of-the-art computational science methods. Its aim is to facilitate modelling of root responses to environmental conditions as well as the impact of root on soil. In the future, we plan to extend this approach to the aboveground part of the plant.

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

2012 ◽  
Vol 9 (4) ◽  
pp. 4943-4987 ◽  
Author(s):  
V. Couvreur ◽  
J. Vanderborght ◽  
M. Javaux
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Root System ◽  
Water Flow ◽  
Three Dimensional ◽  
Root Water Uptake ◽  
Water Dynamics ◽  
Hydraulic Architecture ◽  
Process Understanding ◽  
Implicit Model

Abstract. 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 much 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 architecture: the standard sink distribution SSD, the root system equivalent conductance Krs and the compensatory conductance 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 contrasted 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 process understanding RWU models and water stress functions operational for field scale water dynamics simulation.

scholarly journals EFFECT OF MACRO-ROUGHNESS ELEMENTS ON TSUNAMI INUNDATION: SINK TERM FORMULAE FOR DEPTH-AVERAGED NUMERICAL MODELS

2018 ◽  
pp. 27
Author(s):  
Stefan Leschka ◽  
Clemens Krautwald ◽  
Hocine Oumeraci
Keyword(s):  
Hydraulic Resistance ◽  
Large Scale ◽  
Numerical Models ◽  
Three Dimensional ◽  
Bottom Surface ◽  
Tsunami Propagation ◽  
Tsunami Inundation ◽  
Sink Term ◽  
Roughness Elements ◽  
Computational Element

Tsunami propagation and inundation are commonly simulated using large-scale depth-averaged models. In such models, the quadratic friction law with a selected Manning’s coefficient is generally applied to account for the effect of bottom surface roughness in each computational element. Buildings and tree vegetation in coastal areas are usually smaller than the computational element size. Using empirical Manning’s coefficients to account for such large objects is not physically sound and, particularly in tsunami inundation modelling, this may result in large uncertainties. Therefore, an improved understanding of the processes associated with the hydraulic resistance of the so-called macro-roughness elements (MRE) is required. Relevant parameters such as shape, height and arrangement of the MRE should be investigated through laboratory experiments or numerical tests using a well-validated three-dimensional CFD model. Given the correlation of such parameters to the MRE-induced hydraulic resistance, empirical formulae were developed and directly implemented as sink terms in depth-averaged numerical solvers such as non-linear shallow-water (NLSW) models.

Sign in / Sign up

Export Citation Format

Share Document