Spatial Variation in Soil Chemical Properties Associated with Agrochemical Use in Farming Communities of Oju Local Government Area, Benue State, Nigeria (Published)
This study examined the spatial variation in selected soil chemical properties associated with agrochemical use in farming communities of Oju Local Government Area (LGA), Benue State, Nigeria. A comparative field-based design was adopted across seven farming communities—Ibilla, Ukpa, Iyeche, Owo, Oboru, Uwokwu and Oju. Twenty-eight soil samples comprising 14 agrochemical-treated and 14 control samples were collected at depths of 0–15 cm and 15–30 cm and analysed for selected chemical properties using standard laboratory procedures. The results revealed considerable spatial and depth-related variation. Soil pH ranged from 6.08 to 6.52, indicating slightly acidic to near-neutral conditions. Soil organic carbon (SOC) was consistently higher in control soils, with values of 14.0% and 12.6% at 0–15 cm and 15–30 cm, respectively, in Owo, compared with 10.3% and 10.1% in treated soils. In Uwokwu, control SOC values of 14.3% and 13.88% exceeded treated values of 10.6% and 10.4%. Organic matter ranged from approximately 1.7% to 4.5%, while total nitrogen ranged from 0.01% to 0.12%. Available phosphorus reached 2.49 mg/kg in treated surface soil at Owo. Exchangeable potassium and calcium reached maximum surface values of 0.38 and 4.30 cmol(+)/kg, respectively, at Uwokwu. The study concludes that, active agrochemical use was most consistently associated with lower SOC, whereas other properties exhibited variable spatial and depth-related patterns. The study therefore recommends integrated soil fertility management, appropriate agrochemical application, soil testing and regular monitoring.
Keywords: Oju LGA, Soil fertility, Spatial variation, agrochemicals, soil chemical properties