 |
| Titel |
A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach |
| VerfasserIn |
V. Couvreur, J. Vanderborght, M. Javaux |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 8 ; Nr. 16, no. 8 (2012-08-23), S.2957-2971 |
| Datensatznummer |
250013439
|
| Publikation (Nr.) |
 copernicus.org/hess-16-2957-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|