HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Free via Open Access OA Abstract OA Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Javaux, M. Articles by Vereecken, H. Search for Related Content PubMed Articles by Javaux, M. Articles by Vereecken, H. GeoRef GeoRef Citation Agricola Articles by Javaux, M. Articles by Vereecken, H. Related Collections Water Stress Root Growth/Water Uptake Models Plant and Environment Interactions

Use of a Three-Dimensional Detailed Modeling Approach for Predicting Root Water Uptake

^a Institute for Chemistry and Dynamics of the Geosphere, Agrosphere Institute, ICG-IV, Forschungszentrum Juelich GmbH, D-52425 Juelich, Germany
^b Julich Supercomputing Center, Forschungszentrum Juelich GmbH, D-52425 Juelich, Germany. M. Javaux also Dep. of Environmental Sciences and Land Use Planning, Université Catholique de Louvain, Croix du Sud, 2, bte 2, B-1348 Louvain-la-Neuve, Belgium

View larger version (21K): [in this window] [in a new window]   FIG. 1. Water retention (), hydraulic conductivity (K), water capacity (C), and water diffusivity (D) for loam (continuous line), clay loam (dashed line), and clay soils (dotted line) as a function of pF = log10(|h|), where h is the water potential (cm). Root conductivity is given by the gray horizontal line. Open circles characterize the threshold at which the soils and the root have the same hydraulic conductivity.

View larger version (57K): [in this window] [in a new window]   FIG. 2. (a) Root architecture and initial water potential distribution; (b) xylem water potential after 5 d for Collar Boundary Condition 2; (c) soil water potential distribution after 5 d, white arrows show water streamlines; (d) soil water content distribution; and (e) sink term distribution.

View larger version (16K): [in this window] [in a new window]   FIG. 3. Time series of the water flow rate at the root collar (Jc) for Collar Boundary Conditions 1 (upper) and 2 (lower). Line colors refer to different root or soil parameterization: reference (black), xylem conductivity multiplied by 10 (blue), radial conductivity multiplied by 10 (green), and soil hydraulic conductivity multiplied by 10 (red).

View larger version (82K): [in this window] [in a new window]   FIG. 4. Cross-sections of the three-dimensional soil water content distribution after 1 d with constant water potential at the root collar h = –1000 cm (Collar Boundary Condition 1, Table 1). Comparison between the reference (extreme right) and 10-fold increase of xylem conductivity (Kx), radial conductance (Kr*), and saturated soil conductivity (Ks). Root architecture is shown in white.

View larger version (79K): [in this window] [in a new window]   FIG. 5. Cross-sections of the three-dimensional soil water content distribution after 7 d with constant water flux at the root collar Jc = –10 cm3 d–1 (Collar Boundary Condition 2, Table 1). Comparison between the reference (extreme right) and 10-fold increase of xylem conductivity(Kx), radial conductance (Kr*), and saturated soil conductivity (Ks). Root architecture is shown in white.

View larger version (22K): [in this window] [in a new window]   FIG. 6. Sink-term profile for Collar Boundary Condition 1 (left) and 2 (right). Line colors refer to different root or soil parameterization: reference (black), xylem conductivity multiplied by 10 (blue), radial conductivity multiplied by 10 (green), and soil hydraulic conductivity multiplied by 10 (red). For clarity, the dashed line represents the normalized root length density (RLD) profile multiplied by 10.

View larger version (33K): [in this window] [in a new window]   FIG. 7. Averaged water content () profile, averaged horizontal component of the velocity field (vh) profile, and averaged vertical component of the velocity field (vz) profile after 0.5 and 7 d for Collar Boundary Conditions 1 (continuous lines) and 2 (dashed lines). Line colors refer to different root or soil parameterization: reference (black), xylem conductivity multiplied by 10 (blue), radial conductivity multiplied by 10 (green), and soil hydraulic conductivity multiplied by 10 (red).

View larger version (35K): [in this window] [in a new window]   FIG. 8. Water content variability profile [CV()] and coefficients of variability of the horizontal component of the velocity field profile [CV(vz)] and the horizontal component of the velocity field profile [CV(vh)] after 0.5 and 7 d for Collar Boundary Conditions 1 (continuous lines) and 2 (dashed lines). Line colors refer to different root or soil parameterization: reference (black), xylem conductivity multiplied by 10 (blue), radial conductivity multiplied by 10 (green), and soil hydraulic conductivity multiplied by 10 (red).

View larger version (18K): [in this window] [in a new window]   FIG. 9. Time series of the water flux at the root collar (Jc) for Collar Boundary Conditions 1 (upper) and 2 (lower). Continuous lines refer to loam, dashed lines to clay loam, and dotted lines to clay soils.

View larger version (81K): [in this window] [in a new window]   FIG. 10. Cross-sections of the three-dimensional water potential distribution after 7 d with constant water flux at the root collar (Collar Boundary Condition 1, Table 1) for the three soil types. Root architecture is shown in white.

View larger version (85K): [in this window] [in a new window]   FIG. 11. Cross-sections of the three-dimensional distribution of the ratio between soil and root conductivity (log10[K(h)/Kr]) after 7 d with constant water flux at the root collar (Collar Boundary Condition 2, Table 1) for the three soil types. Root architecture is shown in white.

View larger version (19K): [in this window] [in a new window]   FIG. 12. Profile of the sink term for the standard Collar Boundary Condition 3.

View larger version (45K): [in this window] [in a new window]   FIG. 13. Prescribed (dashed line) and actual (continuous line) flux at the root collar under Collar Boundary Condition 3 with 10 times larger maximum transpiration.

View larger version (33K): [in this window] [in a new window]   FIG. 14. Normalized sink term (S*) vs. averaged water content (upper left) and averaged bulk water potential (upper right), and S* divided by the root surface density (RSD) vs. averaged water content (lower left) and averaged bulk water potential (lower right).