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Influence des prélèvements racinaires sur le fonctionnement hydraulique du drainage. Application à une culture de canne à sucre

Abstract : Subsurface drainage systems are installed to control water-tables and salinity in many irrigated areas. This work concerns a better understanding of the hydraulic functioning of drainage in this context. The particular case of irrigated sugarcane, cultivated in the Gharb plain in Morroco, was studied, in laboratory at the plant scale and in field at the drained system scale. A laboratory experiment with one plant grown in a lysimeter firstly showed that root water uptake of this sugarcane variety was not affected by prolonged waterlogging. Two different water transfer models based on different root water uptake (RWU) functions used as sink terms in the Richards equation were used to predict the pattern of RWU of the sugarcane developed in the laboratory experiment. The first model, Hydrus-2D (Simunek et al., 1996), is based on the a-model RWU where RWU depends on a reduction function varying according to the soil water pressure head and to the root density. The second model, SIC (Système Interactif de Conception) (Breitkopf and Touzot, 1992) is based on the Yr-model where RWU is proportional to the difference between soil and root pressure heads, to unsaturated hydraulic conductivity and to root density. The predictions compared well with the measured values and showed that sugarcane roots mainly absorbed water in the water-table. However, while good predictions were obtained using the actual root density profile with the Yr-model, it was necessary to modify this profile to obtain proper results using the a-model. At the drained system scale, simulations showed that transpiration affects drainage functioning. Transpiration has to be taken into account for subsurface drainage design.
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https://hal.inrae.fr/tel-02580146
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Submitted on : Thursday, May 14, 2020 - 8:14:45 PM
Last modification on : Thursday, December 30, 2021 - 3:18:56 PM

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  • HAL Id : tel-02580146, version 1
  • IRSTEA : PUB00009797

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R. Chabot. Influence des prélèvements racinaires sur le fonctionnement hydraulique du drainage. Application à une culture de canne à sucre. Sciences de l'environnement. Doctorat spécialité Terre Océan Espace, INAPG, 2001. Français. ⟨tel-02580146⟩

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