Water Resource Impacts of Irrigation: The Case of the Main Irrigation Canal from the M’Pourie Plain to Rosso in Mauritania

Abstract

An important factor in determining agricultural production is the availability of irrigation water in the main canal of the M’Pourie plain. This factor affects both the intensification of crops and the size of the irrigation areas. The main Senegal River canal in Rosso, Mauritania, runs across the Plaine of M’Pourie. This study aims to assess the physicochemical quality of the water used for irrigation and agriculture in the main irrigation canal on the M’Pourie plain. The measurements were made from 2021 to 2022, and the following physical and chemical parameters were monitored: pH, temperature, electrical conductivity, salt content, calcium, magnesium, sodium, and potassium; ammonium bicarbonate; chloride; nitrite; nitrate; nitrogen; sulfate; and sodium adsorption ratio (SAR). These measurements were analyzed using volumetric, spectroscopic, and spectrophotometric methods. After conducting statistical analysis and comparing the results with Moroccan quality standards for surface water utilized in irrigation, it has been discovered that the average pH value is 7.51, indicating a neutral state. However, the average nitrite and ammonium values exceed Moroccan standards at 5.16 mg.L-1 and 0.41 mg.L-1, respectively. The water’s low mineralization is attributed to its low electrical conductivity, with an average of 52.2 μS.cm-1. Based on the analysis of the Senegal River water used for irrigation in the M’Pourie plain, it has been determined that its sodium adsorption ratio and electrical conductivity classify it as belonging to class C1S1. This indicates that the water has low salinity and is excellent for irrigation, with a low risk of alkalinization.