Assessment of the suitability of water quality for irrigation in Ogbomoso, Oyo State

The perpetual decline of the quality of available surface water resources due to increasing global pollution menace necessitates the needfulness for suitability assessment of river water resources for irrigation purposes. Water samples were collected during the dry season (November, 2018) and wet season (July, 2019) into sterilized, labelled bottles and were transported in ice packed to laboratory for analyses. Results showed the pH 6.87-6.91, calcium 36-38 mg/l, magnesium 8-9 mg/l, potassium 2.40–2.50 mg/l, sodium 1.28-1.46 mg/l, bicarbonate constant at 180 mg/l, phosphate 0.08-0.11 mg/l, electrical conductivity constant at 0.06mg/l, Nitrate 0.04–0.41 mg/l, sulphate 26-28 mg/l, total dissolved 33.30-34.10 mg/l, chloride 7.5-9 mg/l for the dry season and the pH range of  7.15-7.33, calcium 30-32 mg/l, magnesium 17-18 mg/l, potassium 2.70–2.80 mg/l, sodium 1.86-1.88 mg/l,  bicarbonate 290-295 mg/l, phosphate 0.11-0.12 mg/l, electrical conductivity 0.13-0.14 mg/l, Nitrate constant at 0.07mg/l, sulphate 35-36 mg/l, total dissolved solid 64.30-67.50 mg/l, chloride 12-14 mg/l for the rainy season. Most of the samples analyzed were within the recommended limits set by [22], [13] for irrigation water standard. The water quality indicators SAR,0.05; SSP,2.28; KR,0.02; PI,78.03; RSC1.37 for dry season and SAR, 0.07; SSP, 2.62; KR, 0.03; PI, 73.28; RSC, 1.79 for rainy season were under safe limits.