Role of carrier-based biofertilizer in reclamation of saline soil and wheat growth

Two plant growth promoting rhizobacteria (PGPR), Pseudomonas moraviensis and Bacillus cereus, were used as bioinoculants on wheat, applied alone and in combination. Ground maize straw and sugarcane husk were used as carriers. Experiment was conducted for two consecutive years (2010 and 2011) under axenic conditions in the greenhouse of Quaid-e-Azam University, Islamabad. Sodium chloride (NaCl) (150 mM) was applied with irrigated water after 7 and 14 days of seed germination. Measurements made 40 days after sowing (DAS) revealed that P. moraviensis and B. cereus have better survival efficiency (as evidenced by higher colony forming units (CFUs)) in the carriers. The substantial increase in CFU of both PGPR was also observed in the soil at 57 DAS. Coinoculation of PGPR with both the carrier materials significantly decreased electrical conductivity (EC) and Na⁺ content of soil over control. The N, P, K⁺, Ca⁺, and Mg⁺ contents were 30–40% higher in soil, and 30–45% higher in leaves. Coinoculation of PGPR with carriers significantly increased chlorophyll, protein, sugar, phytohormone contents, and antioxidant activities of leaves. The application of biofertilizers improved the yield of wheat by 15–25% over control. It is inferred that the carriers assisted PGPR for long-time survival, and the formulation was applicable in promoting crop production under salt stress.