Northern Niayes is an area where agriculture is the main activity. Water used for irrigation in this area comes exclusively from groundwater. Farmers do not have access to electricity, thus fuel is the main source of energy used, which is very expensive. The objective of this study was to assess the techno-economic feasibility of solar irrigation pumps. Regarding technical feasibility, pump sizing was carried out on the basis of irrigation management, irrigation techniques, and water distribution. Also, the economic feasibility was studied on the basis of the Net Present Value, Benefit-Cost Ratio, Internal Rate of Return and Payback Period. Results showed for cultivated area ranging from 0.05 ha to 1.91 ha, pumps' flow rate does not vary greatly from one irrigation technique to another. It varies between 2.5 m 3 /h and 31 m 3 /h. However, pressure and power are higher when using drip and sprinkler irrigation techniques, ranging from 27.8 m to 39.9 m for drip and 40.1 m to 58.5 m for sprinkler irrigation. The power varies between 0.05 kW and 1.6 kW for manual, between 0.05 kW and 2.5 kW for drip and between 0.1 kW and 4.75 kW for sprinkler irrigation. The investment cost is variable (669 euros to 21,400 euros), depending on the cultivated area, pump brands and characteristics, and irrigation techniques. Results show that the investment cost ranges from 669 euros (438,500 CFA) to 4090 euros (2,683,000 CFA) when using the manual irrigation technique, from 1281 euros to 20,600 euros when using the drip irrigation technique and from 819 euros to 21,403 euros when using sprinkler irrigation technique for individual pumps. The investment cost is higher when using reservoirs.

Solar irrigation pumps are considered as an alternative to the use of diesel and electric pumps due to the high cost of energy. These pumps are now increasingly used in the Niayes area. Thus, a more in-depth knowledge about the components of a solar pumping system and their characteristics available on the market as well as prices can be beneficial. This study was conducted to have an idea on the baseline of the use of solar irrigation pumps in this area. To perform this study, surveys were conducted among 12 suppliers and 10 service providers located in Dakar, Thies, Louga and Saint-Louis region and among 53 users located in Potou area which is in Louga region. Results show a wide range of pump brands and characteristics. Brands found were Lorentz, LIKOU, SHIMGE, Grundfos, Solar pump, Feili, Difful, JUQIANG, Solar tech, and Asaman. The pumps' flow rate varies between 2.5 m 3 /h and 45 m 3 /h, the pressure ranges from 15 m to 160 m and the power is between 0.072 kW and 10 kW. The price of these pumps varies depending on the brand used and their characteristics. In addition, other materials are available, such as panels with power ranging from 80 W to 330 W and electric cables. The price of these components varies according on the type used. Thus, the investment cost for implementation varies between 640 euros (420,000 CFA) and 25,087 euros (16,455,919 CFA). The cost of installation varies between 76.3 euros (50,000 CFA) and 1219.6 euros (800,000 CFA). Concerning maintenance, it is generally free during the warranty period when the equipment is supplied and installed by the same company. However, the cost of maintenance varies between 152.5 euros and 457.4 euros/year or is estimated at 45.

Wetlands are very important because of the wide range of ecosystem services they provide. Despite their ecological, social and environmental importance, these ecosystems are threatened and fragmented under the combined effects of climate change (CC) and man-made activities (MMA). Such a state of things could be exacerbated by the advent of the coronavirus disease 2019 (COVID-19) pandemic with its many implications. In order to help decision-makers take good decisions, the combined effect of CC, MMA and COVID-19 on the livelihoods of communities around wetland ecosystems have been reviewed based on available scientific knowledge. First, we analyzed the different concepts and theories underlying the wetlands-related studies and then summarized the merits and demerits of the different methodologies underlying wetland studies. The empirical evidences that exist in previous literatures have been highlighted. Similarly, common livelihood strategies for wetland communities in Sub-Saharan Africa (SSA) have been highlighted. The diversity of wetlands’ functions and services makes them a source of livelihood, food security and poverty alleviation for riverside communities. However, these communities lack the knowledge and awareness to understand the impact of their activities and CC on their livelihoods. The review also helped to identify that, out of the three factors investigated, the livelihoods of rural wetland dwellers in SSA are mostly influenced by CC and MMA. However, climate change and COVID-19 remain life-altering transboundary threats that extend in space and time, with large uncertainties on wetlands communities livelihoods.

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.