ASSESSMENT OF OPTIMAL SUBSURFACE CONDITIONS FOR PALM OIL PLANTATION IN ABRAKA USING GEOPHYSICAL DATA AND SOIL ANALYSIS

The study utilized Vertical Electrical Sounding (VES) with a dipole-dipole configuration to investigate subsurface conditions in oil palm plantations in Abraka, Delta State, Nigeria. Complementary soil analysis assessed critical subsurface characteristics for oil palm cultivation. The ABEM SAS 1000 Terrameter was used for data acquisition. Results revealed significant variations in subsurface resistivity and soil properties. At Otorho Road plantation, low resistivity values (116–199 Ωm) indicated high moisture content and fine soil textures, favourable for palm growth. Areas with resistivity exceeding 200 Ωm suggested dry, coarse soils, potentially restricting root penetration and water retention. At Oria, resistivity ranged from low (0.99–45.5 Ωm), indicating high moisture, to moderate (50–300 Ωm), representing well-drained soils. High resistivity zones suggested soil compaction, which may hinder root development. In Erho, low-resistivity zones indicated optimal conditions, while high-resistivity regions suggested compacted soils or geological constraints. Soil analysis revealed differences in nutrient content and pH across locations. Otorho exhibited moderately acidic soil (pH 5.30–6.10), potentially leading to nutrient leaching, with sufficient but lower boron (61.10 mg/kg), nitrogen (0.24%), and phosphorus (24.80 mg/kg). Oria had a near-neutral pH (6.30–6.70), higher boron (84.29 mg/kg), and nitrogen (0.29%), supporting better vegetative growth. Erho showed optimal conditions (pH 6.80) with the highest boron (91.82 mg/kg), nitrogen (0.34%), and phosphorus (61.43 mg/kg), enhancing plant development.