Programme  OS1s Hydrological diagnosis and forecasting: Advanced computational approaches  abstract 246

Spatially Distributed Water Fluxes in an Andisol Under Banana Plants: Experiments and 3D Modeling

Author(s): Julie Sansoulet, Yves-Marie Cabidoche, Philippe Cattan, Stéphane Ruy, Jirka Simunek

Keyword(s): Water fluxes, spatial distribution, stemflow, lysimeters, tensiometers, modelling,

Article: abs246_article.pdf
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Session: OS1s Hydrological diagnosis and forecasting: Advanced computational approaches

fluxes in the subsurface of forested and agricultural ecosystems are spatially widely variable because of several

interconnected phenomena. On the one hand, subsurface environments are often highly heterogeneous. On the other

hand, infiltration water is often distributed unevenly due to above-ground interception and redistribution of rainfall by

the plant canopy. These phenomena have important hydro-ecological consequences because they significantly affect

groundwater recharge and nutrient leaching. Field experiments involving subsurface lysimeters and tensiometers were

carried out to quantify the spatial distribution of fluxes in an andisol under a banana plant. Wick lysimeters were

installed at a depth of 70 cm at several locations with respect to the banana stem to measure spatial distribution of

subsurface water fluxes. Collected experimental data were simulated using the HYDRUS software package that

numerically solves the Richards equation describing three-dimensional variably-saturated water flow in the

subsurface. Spatially distributed drainage fluxes were well reproduced with the numerical model. Due to the impact

of stemflow, drainage volumes under the banana stem were up to six times higher than in the row downstream from

the stem, as well as between rows, as these areas were sheltered from direct rainfall by the banana leaves and

received only throughfall.

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