Analysis of the effects of climate change on pH and salinity of soil in Bakoum valley watershed (Sedhiou Region/Senegal)

Abstract

. In Senegal, the effects of climate change have led to increased salinization, acidification and silting of arable land. Agricultural land management using geomatics tools has become essential for sustainable agriculture. The aim of this study is to determine the impact of salinization, acidification and siltation in the valley of the Bakoum watershed. For this purpose, Aster images (MNT) with a resolution of 30 m were used. This operation was followed by the taking of GPS points in the study area in order to geolocate the infrastructures and delimit the areas lost by the degradation phenomena. A total of 36 soil samples were taken, including 24 samples at depths of 0-20 cm and 20-40 cm in 2015; and 12 samples at depths of 0-20 cm and 20-40 cm in 2017. They were analysed in the laboratory to assess electrical conductivity and pH in 2015 and 2017. In two years, the salinity of the valley soils varied from 83 to 9540 µohm in 2015 and from 20 to 7440 µohm in 2017. Acidity (pH) ranged from 3.6 to 4.2 in 2015 and 3.16 to 4.8 in 2017. The area lost due to salinity, acidity and silting is estimated at 31 ha, i.e. 0.74% of the valley area. These results show that urgent measures must be taken to better exploit the valley's rice-growing potential and thus contribute to the revival of rice-growing activities in the region.