Soil hydraulic properties in relation to local rapid soil changes induced by field drainage: a case study
2009
Frison, A. | Cousin, I. | Montagne, D. | Cornu, S.
The impact of human activities on soil changes is poorly recognized and quantified. We performed an experiment to estimate the impact of 20 years, subsurface drainage on water retention in an Albeluvisol. The studied soil comprises heterogeneous horizons that exhibit a complex juxtaposition of two elementary pedological volumes (EPVs) with a silty white and a clayey ochre EPV. The water retention characteristics of each EPV were determined at four distances from the drain in the E&Bt heterogeneous horizon. The water retention property of the whole horizon was calculated by using an additive equation in order to obtain the available water content of the horizon, and thus to estimate the soil functioning. Whatever the distance to the drain, the silty white EPVs retained more water for water potentials between saturation and approximately -300 cm than the clayey ochre EPVs, and less for water potentials lower than approximately -300 cm. The available water content of the white EPVs and the whole horizon increased near the drain. These changes in water retention properties were interpreted in terms of effects on the horizon structure, which were enhanced by the horizontal fluxes enhanced by the installation of the drains. The present work demonstrates the great influence of agricultural drainage on rapid soil change and on soil spatial variability.
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