Abstract

The rice-growing area of ​​Maga is located in the floodplain of Lower Logone. It covers an irrigable area of ​​more than 7000 ha of arable land. This area is indeed subjected to groundwater quality studies. Three campaigns of water sample studies were performed for one year in 15 points including nine boreholes and six domestic feed wells. Temperature, pH, EC, as well as Ca²⁺, Mg²⁺, Na⁺, K⁺, NH₄⁺, HCO₃^-, NO₃^-, Cl^-, SO₄^2- and PO₄^2- were analyzed for these water samples. The results showed that these waters have a medium degree of mineralization, resulting in facies of carbonated sodium and potassium type, then bicarbonate calcium and magnesium. The levels of calcium, magnesium, sodium, potassium, bicarbonates, chlorides and sulphates are much lower than those recommended by World Health Organization (WHO) for human feed water. The contents of ammonium, nitrates and phosphates are in most waters samples above WHO prescribed level (0.5, 50 and 0.5 mg/L). These ions in high proportions have an anthropogenic origin because of the practice of rice farming. The sodium adsorption ratio (SAR) allowed us to qualify groundwater intended for irrigation.

Key words: Physicochemical, groundwater, mineralization, Maga.