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

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.

[1]  J. Vanderborght,et al.  Towards quantitative root hydraulic phenotyping: novel mathematical functions to calculate plant-scale hydraulic parameters from root system functional and structural traits , 2017, Journal of Mathematical Biology.

[2]  Mathieu Javaux,et al.  Model-assisted integration of physiological and environmental constraints affecting the dynamic and spatial patterns of root water uptake from soils. , 2010, Journal of experimental botany.

[3]  Mathieu Javaux,et al.  Going with the Flow: Multiscale Insights into the Composite Nature of Water Transport in Roots1[OPEN] , 2018, Plant Physiology.

[4]  W. Riley,et al.  Incorporating root hydraulic redistribution in CLM4.5: Effects on predicted site and global evapotranspiration, soil moisture, and water storage , 2015 .

[5]  E. Steudle,et al.  Water Transport across Maize Roots : Simultaneous Measurement of Flows at the Cell and Root Level by Double Pressure Probe Technique. , 1991, Plant physiology.

[6]  J. Durand,et al.  Disentangling temporal and population variability in plant root water uptake from stable isotopic analysis: when rooting depth matters in labeling studies , 2020, Hydrology and Earth System Sciences.

[7]  K. Metselaar,et al.  Macroscopic Root Water Uptake Distribution Using a Matric Flux Potential Approach , 2008 .

[8]  Mathieu Javaux,et al.  Estimation of the hydraulic conductivities of lupine roots by inverse modelling of high-resolution measurements of root water uptake. , 2016, Annals of botany.

[9]  K. Metselaar,et al.  Modeling Water Potentials and Flows in the Soil–Plant System Comparing Hydraulic Resistances and Transpiration Reduction Functions , 2013 .

[10]  Valentin Couvreur,et al.  GRANAR, a Computational Tool to Better Understand the Functional Importance of Monocotyledon Root Anatomy1[OPEN] , 2019, Plant Physiology.

[11]  G. Katul,et al.  Tree root systems competing for soil moisture in a 3D soil–plant model , 2014 .

[12]  H. Talpaz,et al.  A MACROSCOPIC‐SCALE MODEL OF WATER UPTAKE BY A NONUNIFORM ROOT SYSTEM AND OF WATER AND SALT MOVEMENT IN THE SOIL PROFILE , 1976 .

[13]  Keith L. Bristow,et al.  Current Capabilities and Future Needs of Root Water and Nutrient Uptake Modeling , 2002 .

[14]  X. Draye,et al.  Water movement through plant roots – exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties , 2017 .

[15]  W. R. Gardner,et al.  Some Observations on the Movement of Water to Plant Roots1 , 1962 .

[16]  Loïc Pagès,et al.  Estimating the parameters of a 3-D root distribution function from root observations with the trench profile method: case study with simulated and field-observed root data , 2013, Plant and Soil.

[17]  G. Katul,et al.  Biotic and abiotic factors act in coordination to amplify hydraulic redistribution and lift. , 2010, The New phytologist.

[18]  V. Wulfmeyer,et al.  Assessing the relevance of subsurface processes for the simulation of evapotranspiration and soil moisture dynamics with CLM3.5: comparison with field data and crop model simulations , 2013, Environmental Earth Sciences.

[19]  G. Katul,et al.  Plant hydraulics accentuates the effect of atmospheric moisture stress on transpiration , 2020, Nature Climate Change.

[20]  R. Dickinson,et al.  Modeling hydraulic redistribution and ecosystem response to droughts over the Amazon basin using Community Land Model 4.0 (CLM4) , 2014 .

[21]  Jan Vanderborght,et al.  Root Water Uptake: From Three‐Dimensional Biophysical Processes to Macroscopic Modeling Approaches , 2013 .

[22]  H. Vereecken,et al.  Parameterization of Root Water Uptake Models Considering Dynamic Root Distributions and Water Uptake Compensation , 2018 .

[23]  Loïc Pagès,et al.  Links Between Root Length Density Profiles and Models of the Root System Architecture , 2012 .

[24]  M. N. Nimah,et al.  Model for Estimating Soil Water, Plant, and Atmospheric Interrelations: I. Description and Sensitivity , 1973 .

[25]  A. Schnepf,et al.  A functional-structural model of upland rice root systems reveals the importance of laterals and growing root tips for phosphate uptake from wet and dry soils. , 2020, Annals of botany.

[26]  Y. Rothfuss,et al.  Reviews and syntheses: Isotopic approaches to quantify root water uptake: a review and comparison of methods , 2017 .

[27]  X. Draye,et al.  Dynamic aspects of soil water availability for isohydric plants: Focus on root hydraulic resistances , 2014 .

[28]  S. Kanae,et al.  Global Hydrological Cycles and World Water Resources , 2006, Science.

[29]  Loïc Pagès,et al.  Water Uptake by Plant Roots: II – Modelling of Water Transfer in the Soil Root-system with Explicit Account of Flow within the Root System – Comparison with Experiments , 2006, Plant and Soil.

[30]  Jan Vanderborght,et al.  A hybrid analytical-numerical method for solving water flow equations in root hydraulic architectures , 2017 .

[31]  M. Zarebanadkouki,et al.  Stomatal closure prevents the drop in soil water potential around roots. , 2020, The New phytologist.

[32]  N. Jarvis.  Simple physics-based models of compensatory plant water uptake: concepts and eco-hydrological consequences , 2011 .

[33]  Stefan Mairhofer,et al.  Quantification of root water uptake in soil using X-ray computed tomography and image-based modelling. , 2018, Plant, cell & environment.

[34]  Jan Vanderborght,et al.  Horizontal soil water potential heterogeneity simplifying approaches for crop water dynamics models , 2014 .

[35]  Jan Vanderborght,et al.  Connecting the dots between computational tools to analyse soil-root water relations , 2018, bioRxiv.

[36]  Reed M. Maxwell,et al.  Effects of root water uptake formulation on simulated water and energy budgets at local and basin scales , 2016, Environmental Earth Sciences.

[37]  Praveen Kumar,et al.  Competitive and mutualistic dependencies in multispecies vegetation dynamics enabled by hydraulic redistribution , 2012 .

[38]  O. Wilderotter.  An adaptive numerical method for the Richards equation with root growth , 2003, Plant and Soil.

[39]  G. Miller,et al.  A groundwater–soil–plant–atmosphere continuum approach for modelling water stress, uptake, and hydraulic redistribution in phreatophytic vegetation , 2014 .

[40]  Praveen Kumar,et al.  Passive regulation of soil biogeochemical cycling by root water transport , 2013 .

[41]  R. Scott,et al.  Combined measurement and modeling of the hydrological impact of hydraulic redistribution using CLM4.5 at eight AmeriFlux sites , 2016 .

[42]  G. Katul,et al.  Competition for light and water in a coupled soil-plant system , 2017 .

[43]  A. Porporato,et al.  Onset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water dynamics from millimeters to meters , 2008 .

[44]  J. Durand,et al.  Measuring and Modeling Hydraulic Lift of Lolium multiflorum Using Stable Water Isotopes , 2018 .

[45]  Yongjiu Dai,et al.  Incorporating root hydraulic redistribution and compensatory water uptake in the Common Land Model: Effects on site level and global land modeling , 2017 .

[46]  H. Vereecken,et al.  Parameter sensitivity analysis of a root system architecture model based on virtual field sampling , 2019, Plant and Soil.

[47]  S. Rachmilevitch,et al.  A root is a root is a root? Water uptake rates of Citrus root orders. , 2011, Plant, cell & environment.

[48]  Hans-Jörg Vogel,et al.  Modeling Soil Processes: Review, Key Challenges, and New Perspectives , 2016 .

[49]  Jan Vanderborght,et al.  Incorporating a root water uptake model based on the hydraulic architecture approach in terrestrial systems simulations , 2019, Agricultural and Forest Meteorology.

[50]  J. Hopmans,et al.  Transient three-dimensional modeling of soil water and solute transport with simultaneous root growth, root water and nutrient uptake , 1998, Plant and Soil.

[51]  Praveen Kumar,et al.  Numerical simulations of hydraulic redistribution across climates: The role of the root hydraulic conductivities , 2015 .

[52]  K. Trenberth,et al.  Estimates of the Global Water Budget and Its Annual Cycle Using Observational and Model Data , 2007 .

[53]  Jan Vanderborght,et al.  A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach , 2012 .

[54]  Sabine Attinger,et al.  Multiresponse, multiobjective calibration as a diagnostic tool to compare accuracy and structural limitations of five coupled soil‐plant models and CLM3.5 , 2013 .

[55]  H. Franssen,et al.  Soil hydrology: Recent methodological advances, challenges, and perspectives , 2015 .

[56]  Benjamin Smith,et al.  Challenges and opportunities in land surface modelling of savanna ecosystems , 2017 .

[58]  J. Saiers,et al.  Whole root system water conductance responds to both axial and radial traits and network topology over natural range of trait variation. , 2018, Journal of theoretical biology.

[59]  M. Zarebanadkouki,et al.  Hydraulic conductivity of soil-grown lupine and maize unbranched roots and maize root-shoot junctions. , 2018, Journal of plant physiology.

[60]  Jan Vanderborght,et al.  Use of a Three‐Dimensional Detailed Modeling Approach for Predicting Root Water Uptake , 2008 .

[61]  Jan Vanderborght,et al.  Parameterizing a Dynamic Architectural Model of the Root System of Spring Barley from Minirhizotron Data , 2012 .

[62]  Jan W. Hopmans,et al.  Modeling compensated root water and nutrient uptake. , 2009 .

[63]  D. Or,et al.  Hydraulic redistribution in a stand of Artemisia tridentata: evaluation of benefits to transpiration assessed with a simulation model , 2017, Oecologia.

[64]  A C Fowler,et al.  A model for water uptake by plant roots. , 2004, Journal of theoretical biology.

[65]  M. Bouda.  A Big Root Approximation of Site‐Scale Vegetation Water Uptake , 2019, Journal of Advances in Modeling Earth Systems.

[66]  Praveen Kumar,et al.  A model for hydraulic redistribution incorporating coupled soil-root moisture transport , 2007 .

[67]  Jan Vanderborght,et al.  CRootBox: A structural-functional modelling framework for root systems , 2017, bioRxiv.

[68]  Martin Bouda,et al.  Dynamic effects of root system architecture improve root water uptake in 1-D process-based soil-root hydrodynamics , 2017 .

[69]  R. B. Jackson,et al.  Modeling Root Water Uptake in Hydrological and Climate Models. , 2001 .

[70]  Stephen P. Good,et al.  Hydrologic connectivity constrains partitioning of global terrestrial water fluxes , 2015, Science.

[71]  D. Lawrence,et al.  Implementing Plant Hydraulics in the Community Land Model, Version 5 , 2019, Journal of Advances in Modeling Earth Systems.

[72]  Tobias Wojciechowski,et al.  Root cortical senescence decreases root respiration, nutrient content and radial water and nutrient transport in barley. , 2017, Plant, cell & environment.

[73]  Joe Landsberg,et al.  Water Movement Through Plant Roots , 1978 .

[74]  Loïc Pagès,et al.  MODELLING OF THE HYDRAULIC ARCHITECTURE OF ROOT SYSTEMS : AN INTEGRATED APPROACH TO WATER ABSORPTION : MODEL DESCRIPTION , 1998 .