Évolution des terres salées dans le nord de l’estuaire du Saloum (Sénégal)

Faye, Bineta; Tine, Dome; Dethié, Ndiaye; Cheikh, Diop; Faye, Guilgane; Ndiaye, Aminata

doi:10.4000/geomorphologie.13125

Cited by 11 publications

(7 citation statements)

References 4 publications

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“…The difference in salinity noted on the soil profile has already been observed by [12] [13]. It would be due to the dynamics of the groundwater table and the high evaporation of the environment [32]. Indeed, in environments where the water table is shallow, notably in the Niayes area [33], soluble salts are rapidly put back into movement in the whole soil profile by the rise of the water table or by capillary action, due to direct evaporation or through vegetation [21].…”

Section: Soil Salinitysupporting

confidence: 56%

Evaluation of the Effect of Different Leaching Fractions on Soil Salinity

Ndiaye¹,

Diop²,

Sarr³

et al. 2022

CWEEE

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Soil salinisation is one of the main problems in agriculture. To overcome this problem, different methods of managing saline soils are used, including the practice of leaching under irrigation. The objective of this study is to evaluate the effect of different leaching fractions on saline soils in the Nguetiouro lowland in Gandiolais, in Senegal. For this purpose, a completely randomized block set-up has been implemented with three treatments, repeated three times: 1) T0 equivalent to a water volume input equal to the daily reference evapotranspiration (ETo), 2) T1 equivalent to a water volume input equal to the daily reference evapotranspiration plus 10% ETo of leaching and 3) T2 equivalent to a water volume input equal to the daily reference evapotranspiration of the medium plus 20% ETo of leaching. The results showed that leaching has an effect on soil salinity. The initial soil salt storage was reduced by 22.5%, 33.5%, and 50.6% in the first soil horizon, from 0 to 10 cm and by 14%, 35.3%, and 45% at depth from 10 to 30 cm for T0, T1, and T2, respectively. The fitting of simple linear regression models between electrical conductivity and soil moisture showed a negative linear relationship as a function of leaching fractions. The coefficients of determination of model are 0.74 for T0, 0.84 for T1 and 0.86 for T2 in the first soil horizon and 0.63 for T0, 0.83 for T1 and 0.88 for T2 in the depth form 10 to 30 cm. These results can be of great importance in the fight against soil salinity.

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Section: Soil Salinitysupporting

confidence: 56%

Evaluation of the Effect of Different Leaching Fractions on Soil Salinity

Ndiaye¹,

Diop²,

Sarr³

et al. 2022

CWEEE

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“…[20] highlights the same trend in the Senghor Valley with an increase of 79 ha of tans between 1990 and 2005. Furthermore, the findings of [4] show a regression of salt-covered areas in the northern Saloum estuary between 1973 and 1994 and an increase since 1994.…”

Section: Discussionmentioning

confidence: 91%

“…This chemical degradation of the soils has made it impossible to develop land that was previously used for rice production. At the same time, salt extraction activities are developing in the northern Saloum estuary [4]. Thus, the phenomenon of land salinization has taken on the appearance of a real ecological disaster with a strong extension of bare, over-salted spaces, and unfit for agriculture [5].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Land Salinization in the Commune of Fimela (Fatick, Senegal) from 1973 to 2020

Ba¹,

Sambou²,

Ndiaye³

et al. 2023

JGIS

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In Senegal, the agricultural sector remains a major component of the economy and national growth. As the main subsistence activity for 60% of the population, agricultural activity is essential to reduce poverty and ensure food security for the population. In this context, land degradation is a major constraint. In the Fatick region, in the commune of Fimela, land salinization is a worrying environmental problem. The purpose of this study is to understand the dynamics of soil salinization in Fimela in the context of climate change that tends to modify the evolution of landscapes. It required direct observations in the field, socio-economic surveys based on a questionnaire administered in six (6) villages. The processing of the data from these surveys was carried out with Sphinx software for the extraction of data in numerical form and SPSS to carry out the correlations between the collected variables. Excel was also used to perform calculations and make tables and graphs. In addition, the acquisition and processing of Landsat multi-spectral satellite images from 1973, 1988 and 2020 allowed us to observe the evolution of landscape units according to determining climatic events such as drought. The areas of tans have experienced a positive evolution during the period 1973-2020 with an increase of 163.11 hectares or an evolution rate of 7.47%. The localities most affected are Ndangane, Fimela, Djilor, Simal and the villages of the Mar Islands. The overall dynamics of cultivable land are marked by a decline with a rate of change of −18%. Despite the multiple reforestation campaigns, the mangrove has recorded a continuous decrease of 54.58% or a loss estimated at 5335.59 ha during the period 1973-2020. Finally, the analysis of the results of our study shows that land salinization is a determining element of the dynamics of land use and deteriorates the already precarious living conditions of rural populations and compromises the future of the agropastoral production system.

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“…The ∼29,700 km 2 large drainage basin has a Soudano-Sahelian climate, and freshwater input to the estuary is limited to local rainfall (∼700 mm/year), most of which occurs during the wet season from July to October (Doumouya et al 2016). In the course of the Sahelian droughts , a lack of rainfall, coinciding intense evaporation rates, deforestation and tidal seawater intrusions resulted in the inversion of the salinity gradient that generally persists throughout all seasons (Faye et al 2019). As a consequence, salinities increase from the river mouth (∼36) to over 100 in Kaolack, ~110 km upstream, while lower salinities are only rarely observed after the rainy season in the seaward part of the estuary.…”

Section: The Sine-saloum Senegalmentioning

confidence: 99%

“…Following the prolonged droughts in the 1970s in the Sahel zone, intense evaporation and tidal seawater intrusion resulted in the reversal of the formerly 'normal' estuary. At present, the inverse state is essentially modulated by the persistent high evaporation, deforestation (Faye et al 2019), and low discharge and runoff (Descroix et al 2020), despite a potential recovery of rainfall amount in the recent decade (Descroix et al 2020;Faye et al 2020). Regardless of 87 Sr/ 86 Sr measurements, the anomalous Sr and salinity regimes observed in the Sine-Saloum prohibit the establishment of a two-component mixing model due to non-conservative behaviour of Sr and salinity in the mixing zone, as similarly observed in the Coroong Lagoon of South Australia (Shao et al 2021).…”

Section: The Sine-saloummentioning

confidence: 99%

Sr Isotope Ratios (87Sr/86Sr) in Water and Fish Otoliths as Estuarine Salinity Tracers: Case Studies from Three NW African Rivers

Höpker

Lucassen

et al. 2022

Estuaries and Coasts

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Variations of strontium isotope ratios (87Sr/86Sr) in river systems are increasingly utilised to geochemically trace origin and movement patterns of migratory fish species. Accretionary calcified structures, such as otoliths, preserve 87Sr/86Sr signatures of the surrounding water during a fish’s lifetime. In this study, we present 87Sr/86Sr measurements of water samples and catfish otoliths collected in the estuaries of the Sine-Saloum (Senegal), the Gambia River (The Gambia), and the Volta River (Ghana) to assess their systematics and relationships with salinity. The three rivers possess distinct hydrological properties resulting in variable degrees of correlations between 87Sr/86Sr and salinity. The Gambia River (87Sr/86Sr of ~ 0.71209) proved exceptionally preconditioned for the approach due to well-defined geochemical end-members, allowing for quantitative estimates of salinity based on otolith 87Sr/86Sr measurements. The Volta River (~ 0.71392) presents a more complex case due the possible influence of multiple water sources to the main channel, while the inverse salinity gradient and excessive evaporation in the Sine-Saloum estuary (~0.70915) impede any significant correlations between 87Sr/86Sr and salinity. Bulk otolith 87Sr/86Sr values in the Gambia River and Volta River clearly depicted a mixed influence of seawater and riverine compositions, strongly encouraging the application of this approach for geochemical fingerprinting of critical NW African species.

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Évolution des terres salées dans le nord de l’estuaire du Saloum (Sénégal)

Cited by 11 publications

References 4 publications

Evaluation of the Effect of Different Leaching Fractions on Soil Salinity

Evaluation of the Effect of Different Leaching Fractions on Soil Salinity

Dynamics of Land Salinization in the Commune of Fimela (Fatick, Senegal) from 1973 to 2020

Sr Isotope Ratios (87Sr/86Sr) in Water and Fish Otoliths as Estuarine Salinity Tracers: Case Studies from Three NW African Rivers

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