Caron, Jean-François; Banton, Olivier; Angers, Denis A. et Villeneuve, Jean-Pierre (1996). Preferential bromide transport through a clay loam under alfalfa and corn. Geoderma , vol. 69 , nº 3-4. pp. 175-191. DOI: 10.1016/0016-7061(95)00056-9.
Ce document n'est pas hébergé sur EspaceINRS.Résumé
Cropping systems can affect subsurface water quality through modifications of soil hydraulic properties of the unsaturated, near-surface soil. The purpose of this study was to assess the potential impact of two contrasting cropping systems on groundwater contamination by following the distribution in the soil profile of an inert solute under natural rainfall conditions. The experiment consisted of successive applications of 45 kg ha− of KBr, on May 10 and July 25, 1991, to the surface of a St-Laurent clay loam (Typic Haplaquept) which had been cropped with either corn (Zea mays L.) or alfalfa (Medicago sativa L.) for 4 years. Sequential soil sampling was then carried out to determine the depth-wise bromide concentration at various time intervals. Soil samples were taken at three different locations within each plot at 0–8, 8–16, 20–28, 44–52, 68–76, 92–100 and 116–124 cm depths on May 17, May 28 and July 4 after the first application made on May 10. For the second application made on July 25, the samples were taken at the same depths on August 15. For August 15 data, the observed bimodal distribution of Br concentration with depth indicated the preferential flow of solutes. Preferential flow appeared to be more important under alfalfa than under corn. Estimates from all observed data suggested that 39% more bromide was leached out of the 0–30 cm zone in the alfalfa as compared to the corn plots.
It is also shown in this study that changes in cropping practices from corn to alfalfa significantly affect the hydraulic conductivities of the soil and that higher values of hydraulic conductivities were observed at the 50 cm depth in the alfalfa plots relative to the corn plots. These changes appeared to result in increased solute leaching in alfalfa relative to corn plots. Simulation of steady-state stochastic-convective bromide transport from the measured saturated hydraulic conductivity data were consistent with the observed bromide transport data, predicting that, on average, 34% more solute would leach out of the 0–30 cm zone in the alfalfa plots as compared to the corn plots.
| Type de document: | Article |
|---|---|
| Mots-clés libres: | cropping systems; groundwater contamination; soil profile; clay loam; bromide concentration |
| Centre: | Centre Eau Terre Environnement |
| Date de dépôt: | 06 nov. 2024 21:05 |
| Dernière modification: | 06 nov. 2024 21:05 |
| URI: | https://espace.inrs.ca/id/eprint/11186 |
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