ENHANCING SOIL AVAILABLE PHOSPHORUS VIA MICROBIAL INOCULATION IN AN ULTISOL

ABSTRACT

The research was carried out at the Faculty of Agriculture, University of Benin to investigate the availability of soil phosphorus resulting from microbial inoculation in an Ultisol with maize as the test crop. The experiment was laid out in a Randomized Complete Block Design (RCBD) in three replications comprising; T₁ (control), T₂ (NPK_15:15:15) and T₃ (NPK_15:15:15 + Bacillus sp)., to give a total of nine experimental plots measuring 2.5m x2.5m used for the investigation.Results from the work showed a significant effect (P=0.05) of NPK + Bacillus sp on the grain yield (8.7g/18.75m²) of maize than that of the uninoculated treatments (7.7g/18.75m²- 6.6g/18.72m²); while no significant differences were observed in the plant parameters measured until week8 where the leaf area (509.0 cm³) of the inoculated plants (T₃) was significantly better than the values observed for T₁ (350.7 cm)and T₂ (420.3cm) respectively. Available P in soil also increased on the inoculated (20.01 mgkg^-1) treatment than those not inoculated (8.65 – 19.42 mgkg^-1). Although the microbial population (9 x 10³ cfu) in the control (T₁) was relatively higher than the population in T₂ (4 x 10³) and T₃ (7 x 10³), bacillus sp as a promising P – solubilizer was dominant (50 percent) in the inoculated soils (T₃) than the uninoculated.