RESIDUAL EFFECT OF SOILS AMEMNDED WITH N: P: K 15,15,15 FERTILIZER

ABSTRACT

This study was carried out in the soil science experimental farm, University of Benin, to determine the residual effect of soils amended with NPK 15:15:15 fertilizer and microbial inoculum on the growth and yield of maize (Zea mays. L) in an Ultisol. The experiment was carried out in a randomized completely block design (RCBD) having three treatment T₁ (NPK 15:15:15 fertilizer), T₂ (NPK + bacillus spp.) and T₃ (NPK + Pseudomonas + Klebsilla spp.) on previously amended plots. The parameters measured that has already been established includes; number of leaves, plant height, stem girth, leaf width and leaf length. The result showed that phosphorus was found to be limiting and reduced as symptoms of its deficiency was observed during the experiment which reduced from T₁ (19,67mg/kg to 9.50mg/kg) T₂ (19.89mg/kg to 17.70mg/kg) and T₃ (19.90 to 12.30mg/kg). The soil pH remained very strongly acidic throughout the planting season. The application of T₃ (NPK + Pseudomonas + Klebsilla spp.) had the highest maize yield (0.58kg) while T₁ (NPK fertilizer) had the highest number of leaf as highest plant and stem girth.