Role of Plant Growth-Promoting Rhizobacteria (PGPR), Biochar, and Chemical Fertilizer under Salinity Stress

Pot experiment was conducted under axenic conditions in a growth chamber with 14h photoperiod at 22/26 degrees C to evaluate the role of biochar, phosphate-solubilizing rhizobacteria (Pseudomonas sp.), and chemical fertilizer under induced salt stress (150mM sodium chloride (NaCl)). Factorial randomized complete plot designs with three replications were used. Biochar and fertilizer were mixed in soil (5:1) while Pseudomonas sp. was applied as seed soaking. Salt stress applied at 3 leaf stage significantly reduced (27%) soil moisture and increased electrolyte leakage, Na and potassium (K) uptake, proline, and antioxidant enzymes. Biochar and Pseudomonas sp. decreased the sodium by 24% and 50%, respectively, and increased proline, soil moisture content, and peroxidase (POD) activity. Fertilizer treatment increased the electrolyte leakage by 73%. The effect of fertilizer was 3-4x higher for proline and POD activity in combined treatment with biochar and Pseudomonas. The fertilizer effect can be augmented by the application of Pseudomonas sp. and biochar to alleviate salt stress.