Skip to Main content Skip to Navigation
Theses

Processus de dissipation des produits phytosanitaires dans les zones tampons enherbées. Etude expérimentale et modélisation en vue de limiter la contamination des eaux de surface

Abstract : The contamination of surface waters by pesticides has become problematic, for aquatic ecosystems but also for fresh water production. Grassed buffer zones can reduce pesticides transport by surface run-off from cultivated plots to streams. The aims of this work are a better knowledge of various processes governing pesticides dissipation in grassed strips, to asses the efficiency of such management practices including the fate of infiltrated pesticides and to validate a predicting tool, useful for future technical guidelines. Following a state of the art concerning potential dissipation processes, a long-term field experimentation has been initiated, in the Beaujolais area (France). The experimental device is used to characterize the coupled propagation of water and herbicide fluxes (diuron), at the soil surface and in the vadoze zone of a grassed strip. Natural and artificial run-off events were recorded at the outlet of a chemically treated vineyard. Both hydrodynamic and adsorption properties of the soil profile were determined. Results show a structural porosity, associated with the vegetal cover, inducing a high infiltration capacity but also a rapid propagation of fluxes. Nevertheless, infiltrated pesticides are retained in the root zone. Simulations were performed with the Hydrus 2D model at the scale of the soil profile, and a coupled version with a kinematic wave surface model was used at the slope scale. Soil water fluxes were accurately simulated with the Richards equation. A mobile-immobile water hypothesis reproduces subsurfacic solute transport as well. The dual and explicit representation of surface and subsurface flows appears to be necessary.
Keywords : thesis
Document type :
Theses
Complete list of metadata

Cited literature [166 references]  Display  Hide  Download

https://hal.inrae.fr/tel-02587117
Contributor : Migration Irstea Publications Connect in order to contact the contributor
Submitted on : Friday, May 15, 2020 - 11:49:40 AM
Last modification on : Wednesday, November 18, 2020 - 11:18:03 AM

File

pub00018490.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-02587117, version 1
  • IRSTEA : PUB00018490

Collections

Citation

Jean-Guillaume Lacas. Processus de dissipation des produits phytosanitaires dans les zones tampons enherbées. Etude expérimentale et modélisation en vue de limiter la contamination des eaux de surface. Sciences de l'environnement. Doctorat en sciences de l'eau dans l'environnement continental, Université de Montpellier II, 2005. Français. ⟨tel-02587117⟩

Share

Metrics

Record views

91

Files downloads

165