Salinization risk assessment of irrigated soils in the Souf Valley (South-East Algeria) using chemical analysis, multivariate statistics, and GIS

In arid regions, such as the Souf Valley in southeastern Algeria, agriculture is the main contributor to economic development. Groundwater irrigation is essential for agriculture, and if excessive or poorly planned, is a major cause of soil salinization. Despite the importance of this, soil salinization risk and groundwater quality here are little known. Therefore, in this study, we evaluated 41 wells in the Souf Valley region to investigate the quality and suitability of the groundwater for irrigation and associated soil salinization risks. Specifically, we performed water sample analysis across these wells, measuring the levels of physicochemical parameters (pH and electrical conductivity) and the concentrations of Ca2+, Mg2+, Na+, K+, SO42−, Cl−, HCO3−, and NO3−. In addition, geographic Information System (GIS) was used to assess and map both water quality and arable land loss due to salinization. The results of this study revealed the predominance of chloride, magnesium sulfate, and chloride-calcium facies. The groundwater nitrate concentrations reached 97.47 mg. L−1 and 92.5 mg. L−1 on the agricultural perimeters of Hassani Abdelkrim and Ourmes, respectively. This water is non-potable as it is too saline, making it unsuitable for irrigation purposes. Our study shows that groundwater pollution and soil salinization in the Souf Valley greatly threaten the future sustainability of agriculture here.