ABSTRACT
The experiment was carried out to determine the interactive impact of NPK fertilizer and soil depth on the physical and chemical properties of the soil in a cassava farm at Green Hills Cassava Farmstead, Ologbo, Edo State. Soil samples were collected at 0-15 cm, 15-30 cm, and 30-45 cm, from three treatments (control, treatment 1 and treatment 2) using the soil auger and core sampler and laboratory analysis was carried out. Statistical analysis was done using Genstat statistical package. The result showed that there were no significant variations in the organic carbon, organic matter, total nitrogen, calcium, CEC, exchangeable acidity and base saturation at (p<0.05) level of probability across all treatments at the three depths (0-15 cm, 15-30 cm, and 30-45 cm). Significant differences were observed in the pH, phosphorus, magnesium, potassium, and sodium at (p<0.05) level of probability. The soil was very acidic across all treatments having a pH range of 4.35-4.76. The soils were low in organic carbon (2.93-9.58 gkg-1), organic matter (5.06-16.56 gkg-1), total nitrogen (0.15-0.48 gkg-1), calcium (0.20-0.28 cmolkg-1), magnesium (0.03-0.20 cmolkg-1), potassium (0.08-0.28 cmolkg-1), sodium (0.18-0.26 cmolkg-³), Cation exchange capacity (0.63- 0.94 cmolkg1), Exchangeable acidity (0.16-0.28 cmolkg-³) and high in phosphorus (67.69-126.02 mgkg-1). The texture varied between sandy loam, loamy sand and sandy clay loam for all the treatments, at the various depths. The physical parameters studied were Bulk density (1.42-1.56 kgm-³), saturated hydraulic conductivity (21.50-35.5 cmhr-1), water-holding capacity (0.19-0.28 m³/m³), total porosity (41.57-46.42%) and Aggregate stability (0.52-0.77 mm). There were significant differences among the physical parameters at (p<0.05) level of probability at the three depths.
