Fig. 3

Acid phosphatase activity (a) and alkaline phosphate activity (b) as a function of P doses (biochar enriched with Bayóvar rock phosphate) and phosphate-solubilizing bacterial inoculation. Two asterisks indicate significant at p < 0.05. ns, no significant; ρNP, ρara-nitrophenyl phosphate. Uppercase letters compare strains within each P dose and lowercase letters compare P doses within each strain by the Scott–Knott test (p < 0.05). Means and standard deviations of four replications. TSP = 200 mg P of triple superphosphate kg^-1 soil