1. Interaction entre érosions hydrique et éolienne sur sols sableux pâturés au Sahel : cas du bassin-versant de Katchari au nord du Burkina Faso
- Author
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Harouna Karambiri, Jean-Pierre Thiébaux, Jean-Louis Rajot, Olivier Planchon, Olivier Ribolzi, Biogéochimie et écologie des milieux continentaux (Bioemco), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Ecole Inter-Etats d'Ingénieurs de l'Equipement Rural (EIER), Groupe des Ecoles inter-Etats EIER-ETSHER, Solutions (UR 176), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Servat, Eric (ed.), Mahé, Gil (ed.), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Laboratoire d'étude des interactions entre sols, agrosystèmes et hydrosystèmes (LISAH), and Institut National de la Recherche Agronomique (INRA)
- Subjects
Wet season ,010504 meteorology & atmospheric sciences ,Management, Monitoring, Policy and Law ,[SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study ,01 natural sciences ,Deposition (geology) ,EROSION EOLIENNE ,RELATION ,BURKINA FASO ,0105 earth and related environmental sciences ,Hydrology ,Global and Planetary Change ,Ecology ,ZONE SAHELIENNE ,PATURAGE ,Sediment ,KATCHARI BASSIN VERSANT ,04 agricultural and veterinary sciences ,Vegetation ,15. Life on land ,BASSIN VERSANT ,Geography ,VARAITION SPATIALE ,040103 agronomy & agriculture ,Erosion ,Land degradation ,0401 agriculture, forestry, and fisheries ,Aeolian processes ,EROSION HYDRIQUE ,Surface runoff - Abstract
In the Sahel, sandy soils are widespread and support not only most of the pearl millet production, the major staple crop in the region, but also grass production for livestock. Parent sediments of these soils have an aeolian origin and are hence prone to wind erosion. Still, their clay content, even though very low, allows physical crust formation during rainfall leading to runoff and water erosion. Squall lines, major rainfall events of the rainy season, are usually preceded by intense wind. Wind and water erosions are therefore closely associated in both time and space, but they are rarely studied simultaneously. Erosion measurements were performed for two years (2001, 2002) on a small catchment of grazing land (1,4 ha) at Katchari, Burkina Faso, a location typical of the Sahel area with under 500 mm annual rainfall. Wind erosion occurs at the onset of the rainy season, from May to 15th of July, when soil cover is the lowest and before the growth of vegetation. On this non-cultivated area, the same dynamic unfolds as that recorded in millet fields in other sahelian studies. Water erosion occurs throughout the rainy season, but certain intense events produce most of the total annual erosion. Wind causes the largest sediment fluxes leading to both erosion (up to 20 Mg/ha per year) and deposition (up to 30 Mg/ha per year) depending on the area in the catchment. Water erosion is one order of magnitude lower than wind erosion and is more intense where wind erosion is highest. Hence, the same area is eroded by both wind and water. Conversely, areas where aeolian deposition occurs are less affected by water erosion and correspond to fertile islands where vegetation grows. From this study, it comes out that there is on the whole no land degradation at the catchment scale, but an intense aeolian and water dynamic leading to substantial spatial variability typical of sahelian landscapes.
- Published
- 2009
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