Heavy anthropic pressures and rainfall crises have led to land degradation and increased the intensity of wind erosion in the Sahel. This erosion transports soil particles and associated nutrients and contributes to the degradation of cultivated and grazed land. The aim of this study is to assess the intensity of wind flux in relation to land use on the Namaro dune ridge, with sandy soils representative of south-western Niger. Its surface is essentially dominated by millet fields and rangelands. The methodological approach consisted in monitoring soil cover by vegetation on a rangeland and a millet field, meteorological parameters (rainfall, wind speed and direction) and associated erosion flux over two annual cycles. Precise, concomitant measurements of saltation and wind speed were used to determine wind erosion threshold velocity for both land uses. Wind erosion flux were measured using sand traps (BSNE) and saltation detectors: sensit and saltiphone. The potential wind erosion flux was also determined. It appeared that the millet field is at all times more covered by vegetation than the rangeland. The two land uses show the lowest land cover at the end of the dry and beginning of the rainy season when the winds are strongest. This difference can be explained by the high grazing pressure on the dune complex, which is maintained throughout the year. As a result, the threshold velocity, which is always lower on the rangeland, was 6.1 m.s -1 compared with 7.3 m.s -1 on the millet field. From July to December, as vegetation developed, threshold velocities increased, reaching 9.6 and 11.1 m.s -1 respectively on the grazing land and the field. In agreement with the vegetation cover, DUP and threshold velocities, horizontal erosion flux and saltation were at least 2 times greater on the rangeland than on the millet field. This is the first time in the Sahel that measurements have shown that rangelands can be more erodible than cultivated fields for the same weather conditions. This underlines the role of grazing pressure on Sahelian rangelands, particularly during the rainy season

In the Sahel, exacerbated soils degradation is an ecological indicator of ecosystem vulnerability. This study examines the effects of restoration of degraded lands on soils physicochemical properties and adaptability of planted woody species over a period of 4-6 years. It is based on: 1) Physicochemical analyses of soils (granulometry, calcimetry, and organic matter) carried out on 102 samples taken in the upper 10 centimeters of the soil profile of the rehabilitated and control sites, 2) measures carried out for the dimensioning of anti-erosion structures, 3) dendrometric measurements on woody species planting in 20 plots each with a rectangular shape 60 m × 30 m as well as characterization of the structure of their root systems. Physicochemical analyses show an improvement in soil quality and structure thanks to the erosion control measures. The degradation of anti-erosion structures, inferred from the rate of siltation of micro-basins, the subsidence of the bulges, the formation, and extension of the breaches, is strongly influenced by the topography, precipitation, and sandy texture of the soils. The restoration activities have led to the reconstitution of vegetation cover on degraded soils. Based on dendrometric characteristics, height class structure, and root systems architecture, significant differences were observed between woody species planted in anti-erosive structures. Eucalyptus camaldulensis groups of with a tracer root system and high density, have the highest structural parameters resulting from the adaptation of this species on Sahelian degraded lands.