10.46243/jst.2022.v7.i09.pp102-116 registered

This study was conducted to evaluate seasonal variations in major soil nutrients and selected physicochemical parameters in small-scale tea farms along the Sulal River in Bureti Sub County, Kericho County, Kenya. Soil samples were collected from ten selected tea farms before and after the application of nitrogen, phosphorus, and potassium (NPK) fertilizer to assess the influence of agricultural practices on nutrient movement into the river. The collected soil samples were analyzed for pH, moisture content, electrical conductivity, nitrate-nitrogen (NO₃-N), phosphorus (PO₃-P), and potassium (K) using standard analytical methods. Data analysis was performed using IBM SPSS 20. The results showed seasonal variations in the measured soil parameters, with significant differences observed between the dry and rainy seasons for most parameters. During the dry season, pH ranged from 4.07 ± 0.03 to 4.98 ± 0.03, moisture content from 12.58 ± 0.52% to 21.76 ± 0.52%, electrical conductivity from 85 ± 7.85 to 245 ± 6.50 μS/cm, nitrate-nitrogen from 0.14 ± 0.03 to 0.87 ± 0.01 mg/L, phosphorus from 0.06 ± 0.03 to 0.32 ± 0.04 mg/L, and potassium from 0.98 ± 0.36 to 2.05 ± 0.28 mg/L. During the rainy season, pH ranged from 4.18 ± 0.03 to 4.80 ± 0.04, moisture content from 12.68 ± 0.52% to 37.36 ± 0.45%, electrical conductivity from 216 ± 3.72 to 289 ± 7.25 μS/cm, nitrate-nitrogen from 0.33 ± 0.04 to 0.90 ± 0.07 mg/L, phosphorus from 0.08 ± 0.07 to 0.68 ± 0.04 mg/L, and potassium from 1.65 ± 0.35 to 3.48 ± 0.15 mg/L. Correlation analysis indicated significant relationships among moisture content, electrical conductivity, phosphorus, and potassium. Overall, the soils exhibited low levels of major nutrients in both seasons, highlighting the need for appropriate soil and fertilizer management practices. Strict legislation and improved management of agricultural soils along river systems are recommended to minimize nutrient movement and protect river water quality.