The development of agriculture in the Mina plain is hampered by the drought that has occurred in recent years. As a result, water scarcity has favoured an intensive use of groundwater of poor quality. This behaviour is one of the forerunners of soil degradation. Knowing the quality of the irrigation water used becomes imperative. In this context, water samples from 178 wells in the Mina plain were subjected to a physico-chemical analysis, mainly electrical conductivity (EC), sodium adsorption ratio (SAR), and irrigation water quality index (IWQI), were used to identify water quality classes as well as residual alkalinity (RSC) to determine salinization pathways. The thematic maps established by the two methods (EC and SAR, IWQI) showed that 73.44% of the total area could be used for irrigation and that 87.55% of the total area may be used for irrigation in soils with high permeability where additional water should be applied to prevent salt accumulation. The residual alkalinity revealed two types of salinization: one neutral and one alkaline, representing respectively 149 and 29 wells. The electrical conductivity varied between 2.24 and 16.50 dS∙m-1, divided into two classes of salinity (C4, 44.03% and C5, 55.97%). SAR values fluctuated between a low of 4.28 and a high of 94.73, with S2 dominance accounting for 49.57% of the total area. IWQI’s assessment of groundwater quality revealed that 87.55% of the Mina study area is severely restricted, which is dominant in the southeastern and southwestern parts of the area. The remaining area, 12.44% or less, is in the high restriction category. This simple index uses the most important parameters that evaluate the quality of irrigation water for management.

The objective of this study is to contribute in assessing and mapping of the salinity risks level of soil and groundwater for irrigation in the Mina plain. The experimentation was carried out on a surface area of 4000 ha. Electromagnetic conductivity (EM) measurements and soil and well water samples were taken and analysed. The results showed an important spatial variability of the electrical conductivity (EC) of saturated paste extracts (ECe), which varied between 1.35 and 28.8 dS/m. The isovalues map of ECe was estimated by the regression equation and interpolated by the ordinary kriging (OK) method which showed that the area of saline soils (ECe > 4 dS/m) represented 90% of the study area. The results also showed poor to unsuitable well water quality. To find the risk of salinity and sodium, the water points were classified as C3S3 (2.5%), C4S2 (5%), C4S3 (30%) and C4S4 (62.5%). Spatial distribution maps of total dissolved solids (TDS), electrical conductivity of water (ECw) and sodium adsorption ratio (SAR) interpolated by inverse distance weighting (IDW) showed too high risk levels of ECw (>5000 μS/cm) and TDS (>3000 mg/l) occupying a large wellfield (70%); with regard to SAR (>18), 36% of the groundwater had a high risk of sodium. These results showed that the choice of tolerant crops, redevelopment of drainage systems and irrigation with less saline water should be designed for the sustainability of soil productivity and agro-ecosystems.