Fluorescent Pseudomonas spp. and Bacillus spp. for phosphate solubilization and growth promotion of garlic

ABSTRACT Garlic is a nutrient demanding crop which requires a high investment for fertilization and especially for phosphate (P) fertilizers, due to its high retention by the soil. It is possible to use the P solubilizing microbiota, especially rhizobacteria, to make P available and reduce fertilization. Fluorescent Pseudomonas spp. (CBS02) and Bacillus spp. (EB17) isolates were tested at triple superphosphate doses (0 % - without triple superphosphate; 50 % - 472.82 kg ha-1; 100 % - 945.65 kg ha-1). The experimental design was randomized blocks, in a 4 x 3 x 4 factorial scheme, with four treatments (CBS02 isolate, EB17 isolate, isolates mixture and control) and four replications. The size, fresh and dry masses, P content of the fourth leaf and yield were evaluated. The mixture of Pseudomonas spp. (CBS02) and Bacillus spp. (EB17) used in the inoculation of the garlic bulbils increased the size, dry mass and P content of the fourth leaf, as well as the yield of the crop without triple superphosphate, indicating that the P solubilization capacity of the isolates was increased when these were combined. It was possible to observe an increment in all the evaluated variables, indicating that the isolates P solubilization capacity was enhanced when they were combined.