Assessment, classification, and mapping of groundwater quality for agriculture in selected farm settlements of southwestern Nigeria

Good water quality is very vital to the productivity and sustainability of irrigated agriculture. The suitability for irrigation of groundwater samples collected and analyzed during dry and wet seasons from Ajegunle, Akufo, and Eruwa farm settlements of southwestern Nigeria were assessed using several irrigation water quality indices (IWQIs). The parameters were analyzed statistically and subjected to correlation. Seasonal spatial distribution maps were generated via GIS. All the water samples from the three farm settlements were found to be mostly soft, fresh, excellent, and suitable for irrigation in both seasons. Meanwhile, soluble sodium percentage (SSP) and Kelly's Ratio (KR) revealed them as unsuitable while other parameters showed different degrees of suitability for different samples from different farm settlements in different seasons. Significant correlations were seen between the selected parameters in both seasons. The distribution maps reveal the spatial distributions of selected parameters within Ajegunle and Akufo farm settlements. Utilizing these findings will enhance systematic groundwater exploitation for irrigation within the settlements. Furthermore, systematic irrigation management practices and crop choices, based on the concentrations and distribution of the parameters viz-a-viz crop requirements should be considered to limit potential dangers that may arise with the use of the water over a long period.