Growth and Yield of Okra Exposed to a Consortium of Rhizobacteria with Different Organic Carriers under Controlled and Natural Field Conditions

Crop yields, soil fertility, and soil quality decline due to the overuse of chemical fertilizers and other agrochemicals. The damaging effects of these agrochemicals on the environment can be minimized by integration with eco-friendly approaches, i.e., biofertilizers. These eco-friendly biofertilizers containing plant growth-promoting rhizobacteria, (PGPR) not only solubilize mineral nutrients for crop uptake but also release phytohormones for their growth improvements. The objective of this research is to use these PGPR’s capacity to promote growth in order to increase okra production. For this purpose, different organic carriers were used, i.e., Press mud, Charcoal, Biochar, Peat, and Compost for PGPR’s inoculation. Before being used as a consortium with various carrier materials, the pre-isolated and characterized PGPR strains (AN-35, ZM-27, and ZM-63) were tested for compatibility against one another. The PGPR consortium and carriers were applied in the following treatments, i.e., T0: (control), T1: PGPR, T2: Peat + PGPR, T3: Pressmud+ PGPR, T4: Compost + PGPR, T5: Charcoal + PGPR, and T6: Biochar + PGPR in the present pot and field studies. Under the pot experiment, the results depicted that all treatments showed a significant increase in okra growth, nutrient contents, and yield of okra along with increasing the microbial biomass in the soil but the treatment containing PGPR consortium with peat caused the maximum increase. Similarly, the results of the field experiment also showed a significant increase under all treatments but the maximum increase in nutrient contents, growth attributes, and yield of okra was found under the treatment containing PGPR consortium with peat (T2). Therefore, this study recommends the use of peat and studied the PGPR consortium as a suitable carrier to develop carrier-based biofertilizers for sustainable okra production.