Interactions entre sol, matiere organique et eau. Illustration par l'etude de 4 sites forestiers de la vallee de la fecht, vosges (france)
Institution:
Université Louis Pasteur (Strasbourg) (1971-2008)Disciplines:
Directors:
Abstract EN:
In the highly straining superficial formations and soils of the fecht watershed, the variability of organic matter describes more than 80 percent of the variability of water retention. The approach of the relationships between soil, organic matter and water has been conducted trough the study of several selected stations. The law of jurin is used as leading thread throughout the study to determine the parameters to be analysed, namely surface tension of aqueous soil solution and liquid-solid contact angle. At microscopic scale, differences in water repellence have been identified between the stations. The ecological characteristics determine the surface tension of soil solution and the water repellence of the porous medium. Water repellence varies with the time factor. At macroscopic scale, the water repellence variations increase the nonlinearity of the water retention curve. It is proposed to integrate these variations into the description of the hydric working of the soil which is considered here as a tent canvas.
Abstract FR:
Dans les volumes sedimentaires tres filtrants du bassin de la fecht, la variabilite de la matiere organique decrit plus de 80% de la variabilite de la retention hydrique. L'etude des relations entre le sol, la matiere organique et l'eau est abordee a l'echelle stationnelle. La loi de jurin sert de fil conducteur a l7etude en indiquant les parametres a apprehender : tension superficielle de la solution du sol et angle de contact liquide-solide. A l7echelle microscopique, on met en evidence des differences de mouillabilite entre les sites. Les caracteristiques ecologiques controlent la tension superficielle de la solution du sol et l'hydrophobie de la matrice poreuse. La mouillabilite varie avec le temps. A l'echelle macroscopique, les variations de mouillabilite accentuent la non-linearite de la courbe bde drainage. On propose d'integrer ces variations dans la description du fonctionnement hydrique du sol qui est alors considere comme une toile de tente.