This study attempts to find a fuzzy logic system for assessing the quality of water in water treatment plants (WTPs) providing water for irrigation purposes in the Basrah Governorate (South of Iraq). Each month, samples are taken in each of six major WTPs to measure electrical conductivity ( EC), and the content of sodium, magnesium and calcium. The calculated value which is the sodium adsorption ratio ( SAR) is plotted with EC on the Richard diagram. SAR and EC values are combined together in a fuzzy inference system (FIS) to find out a quality number called the fuzzy irrigation water quality index number ( FIWQI) which ranges from zero to one. The higher the value of the index, the better water quality. The Richard diagram, which helps to classify irrigation water, is used to adjust FIS components. Results show that the FIWQI for all WTPs changes depending on location and season. It ranges between 0.114–0.170, 0.120–0.190, 0.114–0.170, 0.114–0.202, 0.118–0.500 and 0.46–0.500 for Al-Bradhaia 1, Al-Jubaila 1, Shatt Al-Arab, Garmmah 1, Al-Rebat, and Old Shauaibah WTPs, respectively. The results indicate that WTPs effluent drawn from the Shatt Al-Arab River has poor water quality for irrigation purposes, except for an Old Shauaibah which receives water from another source called a sweet water canal. FIS results are compared with values obtained from the Richard diagram and 96% degree of compatibility between the two methods is attained. This indicates that FIS is an acceptable method for water quality classification.

Groundwater hydrochemistry of Algerian Sahara (Southwest, Algeria) was used to assess groundwater quality to de-termine its suitability for drinking and agricultural purposes. A total of 26 groundwater samples were analysed for 14 para-meters. Standards laboratory methods were used to determine physicochemical groundwater properties. This study shows that these pH, electric conductivity, total hardness, bicarbonate, and phosphate were within WHO limits. The concentration of magnesium ranging from 30.49 to 120 mg∙dm–3 with an average value of 67.21 mg∙dm–3. 38.56% of the water points analysed have a concentration lower than the value set by the WHO at 75.00 mg∙dm–3. It also showed that 70% of the points studied have potassium concentrations that exceed World Health Organization standards. Groundwater of Algerian Sahara is low in nitrogen (NO3–) and the higher concentration may result in various health risks. The result for this study showed that the water was to be found suitable for drinking purposes except for few samples. Piper diagram indicates that groundwater in Adrar belongs to chlorinated-sulphated, sodium and magnesium facies. The groundwater samples of Adrar present high salinity and low alkalinity fall into the field of C3S1 and C3S2. Based on the RSC values, all samples had values less than 1.25 and were good for irrigation.

The aim of the research was to study the temporal and spatial dynamics of a set of agronomic criteria for irrigation water in the process of transporting it from the Southern Buh River intake site to the lands of the Southern Buh and Kamianska irrigation systems situated in southern Ukraine. Six stationary research sites for monitoring the quality of irrigation water were established along the route of irrigation water transportation. Determination of agronomic criteria for irrigation water quality was carried out in two terms: at the beginning of the irrigation season, in May, and at the end, in September. The content of cations of sodium, magnesium, calcium, and anions of chlorine, sulphates, carbonates, and bicarbonates was determined. In the field, the pH and electrical conductivity of water, the total salt content, and the total amount of dissolved solids were determined. It is determined that waters have an average level of danger from the point of view of salinisation of soils. This fact leads to a decrease in yield of sensitive to salinity crops (corn, alfalfa and most vegetables). The high content of sodium cations along with the low content of calcium and magnesium cations indicates the danger of degradation of the physical properties of the southern chernozems and the need to use the meliorants containing calcium. There is a high probability of toxic effects on crops caused by sodium cations. At the same time, it is stated that there is no negative effect of chlorine anions on plants.