Seasonal Variation of Major Inorganic Nutrients and Selected Physicochemical Parameters Levels in Soil from the Athi – Thwake River Catchment Area, Makueni County, Kenya

This study evaluated selected physicochemical parameters and major inorganic nutrients of soil samples from ten specific sites in the Athi-Thwake River catchment area in November 2021 and January 2022 in Makueni County representing wet and dry seasons respectively. The average levels of the physicochemical parameters in the dry and wet seasons, for pH were 4.63 ± 0.25 and 4.43±0.18, electrical conductivities were 122±8.09 µS/cm and 216±2.70 µS/cm, percentage moisture contents were 14.19 ± 0.40 % and 27.92±0.56 % while the major inorganic nutrients levels were, nitrate-nitrogen at 0.24±0.04 mg/kg and 0.37±0.02 mg/kg, phosphate-phosphorous were 0.08±0.05 mg/kg and 0.07±0.03 mg/kg and potassium 1.02±0.15 mg/kg and 1.05±0.35 mg/kg respectively. In the two seasons; pH, electrical conductivities and moisture contents levels had no statistical difference with nitrate-nitrogen, phosphate-phosphorous and potassium (p>.05). The soil samples in both seasons had low major nutrients contents, indicating that the area is already experiencing significant erosion. To prevent further nutrient loss due to water runoff and leaching, soil conservation practices such as contour farming, terracing and cover cropping should be implemented to reduce erosion and retain nutrients in the soil.