The Ability of Phosphorhizobacteria Isolates to Produce Organic Acid and Promote Phosphatase Activity to Increase The Growth of Maize (Zea mays L.) in Selected Medium

Abstract Utilization of phosphorhizobacteria has the potential to increase the growth of maize by producing organic acid and promoting its phosphatase activity. The research to investigate the capability of phosphorhizobacteria isolates to produce organic acids to convert organic P into inorganic P so that P is available and can increase the nutrient uptake by plants. The experiment was conducted at the Soil Biology Laboratory in Department of Soil Science, Faculty of Agriculture, Universitas Padjadjaran. It was arranged as complete randomized factorial design, consisted of 16 treatments (combination of singular and consortia of phosphorhizobacteria isolates: J1M, J3T and J5H and two concentrations) with 3 replications. The suspension of phosphorhizobacteria isolates were inoculated into media Murphy then planted the maize seedlings into it. The produced organic acid, phosphatase enzyme and seedling growth were measured at 14 days after planting. Results showed that phosphorhizobacteria isolates has the ability to produce oxalic acid, tartaric acid, acetic acid, lactic acid and maleic acid along with maize seedlings. The interaction of consortia phosphorhizobacteria isolates (J1M+J3T) capable to increase maize biomass 21.87% higher than control and P uptake by 3.13 mg/100 g. The J5H isolate can significantly promote the highest phosphate solubilizing index and phosphatase activity