Assessment of Water Quality for Irrigation in Dutsin-Ma Dam, Katsina State, Nigeria

Water quality is a critical determinant of agricultural productivity, particularly in semi-arid regions where irrigation is essential. This study assesses the physicochemical characteristics of Dutsin-Ma Dam water to evaluate its suitability for irrigation. With growing reliance on the dam for year-round farming in Dutsin-Ma Local Government Area, Katsina State, understanding water quality is vital to safeguarding soil health and optimizing crop yield. The research employed field-based quantitative methods involving the collection of water samples from three strategic points: the inflow, mid-reservoir, and outflow zones. Standard laboratory analyses were conducted to determine parameters such as pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), nitrate, phosphate, sulfate, bicarbonate, sodium, potassium, calcium, magnesium, and boron. Furthermore, key irrigation suitability indices, including Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP), Magnesium Adsorption Ratio (MAR), Kelly's Ratio (KR), Potential Salinity (PS), and Total Hardness (TH), were calculated using established equations. Results indicated that the dam water exhibits neutral pH (mean = 7.00), low salinity (mean EC = 0.21 dS/m), and low sodium hazard (mean SAR = 0.003), making it suitable for irrigation. However, nitrate levels were significantly high (mean = 14.04 Mg/L), exceeding FAO's safe threshold for irrigation water. This suggests potential non-point source pollution, likely from agricultural runoff or sewage discharge. Other parameters, such as phosphate, sulfate, and boron, were within acceptable limits. The correlation analysis revealed strong relationships between sodium and SAR, magnesium and SSP, and chloride and PS, indicating the dominant influence of these ions on water suitability. Overall, Dutsin-Ma Dam water is safe for irrigation under current conditions, but long-term usage may pose risks without proper management. The study recommends regular water quality monitoring, improved fertilizer management to curb nitrate contamination, and awareness programs for farmers on sustainable irrigation practices.