Enhancing Zea mays growth and drought resilience by synergistic application of Rhizobacteria-Loaded Biochar (RBC) and externally applied Gibberellic Acid (GA)

Drought stands out as a prominent abiotic stressor affecting plants, particularly impactful in arid and semiarid regions, posing a substantial threat to global food security. Biochar, characterized by an expansive surface and high porosity due to carbon-rich pyrolysis exhibits significant water retention capacity. Rhizosphere-dwelling microorganisms, referred to as "rhizobacteria," encompass the category of "Plant Growth-Promoting Rhizobacteria" (PGPR), known for fostering plant growth through various mechanisms. The concurrent application of Rhizobacteria-loaded biochar (RBC) and Gibberellic Acid (GA3) is a promising strategy to enhance maize physiology, growth, and yield under drought-stress conditions. In this study, biochar, derived from crushed corn cobs, was formed and applied to the soil at a 0.75 w/w ratio effectively maintaining three drought levels gravimetrically. Pseudomonas fluorescens combined with biochar and GA3 enhanced maize physiology and growth during drought stress. Applying biochar and GA3 significantly improved protein content, chlorophylls a and b, total chlorophyll, shoot and root length, dry weight, and fresh weight in drought-stressed maize. The combined application of RBC and GA3 markedly outperformed the control, leading to substantial improvements in growth and physiological indices.