Phosphate-solubilising bacteria enhance Oryza sativa growth and nutrient accumulation in an oxisol fertilized with rock phosphate

Abstract

This study aimed to evaluate the ability of phosphate-solubilizing bacteria (PSB) to enhance growth and nutrient accumulation of rice plants grown in an Oxisol fertilized with Bayóvar rock phosphate (BRP). The experiment was entirely randomised and consisted of the following 12 treatments: individual inoculation with five PSB strains in pots containing BRP; a control with BRP without inoculation; five different soluble phosphorus (P) concentrations (50, 100, 150, 200 and 250 mg P2O5 dm−3) applied as NH4H2PO4 and a control without P or inoculation. The PSB strains UFLA 04-21 (Burkholderia sp.), UFLA 03-10 (Paenibacillus kribbensis), UFPI B5-6 (Enterobacter sp.) and UFPI B5-8A (Pseudomonas sp.) increased the shoot dry matter, root dry matter and total dry matter, the number of tillers and the accumulation of phosphorus, nitrogen, calcium, magnesium, sulphur and boron compared with the treatment with BRP without inoculation. The increases in the dry matter of the shoots and roots were 52% and 120%, respectively, with the strain UFLA 03-10 (Paenibacillus kribbensis) inoculation treatment. The four strains promoted shoot dry matter that were equivalent to approximately 60% of the shoot dry matter produced in the treatment with 150 mg dm−3 of soluble P and increased the P accumulation in the shoots compared with the treatments with 50 and 100 mg P2O5 dm−3 of soluble P. These results indicate that inoculation with PSB combined with rock phosphate is an economical and sustainable strategy for improving the growth and nutrient accumulation of the rice plants.