Oxidized Acidic Biochar and Pseudomonas aeruginosa Enhanced Phosphorus Availability and Growth Performance of Transplanted Maize in Acid Soil

Maize plays a vital role in enhancing food security, particularly in regions facing agricultural challenges such as poor soil conditions, erratic rainfall, and limited access to resources. It can be advantageous for smallholder farmers in developing countries, where it can enhance productivity on limited land and under suboptimal soil conditions. One of the potential means for improving crop yield under suboptimal soil conditions, such as acidic soils, is the application of soil amendments. However, the combined effects of functionalized biochar (a pyrogenic carbon) and microbes on phosphorus (P) bioavailability and plant growth performance are still not well understood. This study investigates the optimization of transplanted maize growth in acidic soil through the application of rice husk biochar (RHB) that was oxidized with 10% hydrogen peroxide and inoculated with Pseudomonas aeruginosa, a phosphate-solubilizing bacterium. The oxidized biochar’s pH was adjusted to 6.2 to enhance its effectiveness in challenging soil conditions. Soil properties and maize performance were determined using a pot culture. Results showed that the combined use of 10% oxidized RHB and Pseudomonas aeruginosa significantly increased P availability and phosphatase enzyme activity by 435% and 418%, respectively. Additionally, 10% Oxidized RHB treatment, microbes treatment and combination of biochar and microbes treatment showed yield increment 52%, 51% and 313% respectively, demonstrating the effectiveness of the treatment in improving soil fertility and crop productivity. This improvement in yield might have occurred due to an increase in soil pH, P bioavailability, and a reduction in Al toxicity since there were significant positive relationships between yield and soil pH and available P and a negative relationship with available Al concentration. These findings underscore the potential of integrating oxidized biochar and beneficial microbes, Pseudomonas aeruginosa, to enhance crop performance in acidic soils.