Incessant utilization of chemical fertilizers leads to the accumulation of minerals in the soil, rendering them unavailable to plants. Unaware of the mineral reserves present in the soil, farming communities employ chemical fertilizers once during each cultivation, a practice that causes elevated levels of insoluble minerals within the soil. The use of biofertilizers on the other hand, reduces the impact of chemical fertilizers through the action of microorganisms in the product, which dissolves minerals and makes them readily available for plant uptake, helping to create a sustainable environment for continuous agricultural production. In the current investigation, a field trial employing Arachis hypogaea L was conducted to evaluate the ability of Pseudomonas aeruginosa to enhance plant growth and development by solubilizing minerals present in the soil (such as zinc and phosphorus). A Randomized Complete Block Design (RCBD) included five different treatments as T1: Un inoculated Control; T2: Seeds treated with a liquid formulation of P. aeruginosa; T3: Seeds treated with a liquid formulation of P. aeruginosa and the soil amended with organic manure (farmyard); T4: Soil amended with organic manure (farmyard) alone; T5: Seeds treated with lignite (solid) based formulation of P. aeruginosa were used for the study. Efficacy was determined based on the plant's morphological characters and mineral contents (Zn and P) of plants and soil. Survival of P. aeruginosa in the field was validated using Antibiotic Intrinsic patterns (AIP). The results indicated that the combination treatment of P. aeruginosa liquid formulation and organic fertilizer (farmyard) (T3) produced the highest biometric parameters and mineral (Zn and P) content of the groundnut plants and the soil. This outcome is likely attributed to the mineral solubilizing capability of P. aeruginosa. Furthermore, the presence of farmyard manure increased the metabolic activity of P. aeruginosa by inducing its heterotrophic activity, leading to higher mineral content in T3 soil compared to other soil treatments. The AIP data confirmed the presence of the applied liquid inoculant by exhibiting a similar intrinsic pattern between the in vitro isolate and the isolate obtained from the fields. In summary, the Zn and P solubilization ability of P. aeruginosa facilitates the conversion of soil-unavailable mineral form into a form accessible to plants. It further proposes the utilization of the liquid formulation of P. aeruginosa as a viable solution to mitigate the challenges linked to solid-based biofertilizers and the reliance on mineral-based chemical fertilizers.

The excessive use of phosphorus (P) fertilizers increases crop production but can lead to P-induced zinc (Zn) deficiencies, making both nutrients unavailable to plants. Plant–microbe interactions, such as with Pseudomonas aeruginosa , can alleviate these constraints by solubilizing Zn and P in soil. A soil incubation study revealed that applying P. aeruginosa with farmyard manure (FYM) significantly increased Zn and P solubilization (6.86 mg/l; 14.83 mg/l) compared to control (3.15 mg/l; 13.67 mg/l). A field experiment evaluated the effects of P. aeruginosa on the biochemical composition of groundnut plants under five treatments. The T2, T3, and T4 treatments had the highest protein, carbohydrate, and chlorophyll levels, likely due to the heterogeneous activity of FYM and the mineral solubilizing ability of P. aeruginosa . Groundnut seeds from T3 (combined liquid inoculant and FYM) had the highest iodine (88.47 mg KOH/g), saponification value (195.56 mg KOH/g), and free fatty acid content (2.23 g oleic acid). The pH of the T3 soil decreased from 8.3 to 7.5, and significant increases were observed in electrical conductivity (from 2.88 to 0.30 dS/m), calcium carbonate (2.53–1.7%), organic carbon (0.39–1.91%), nitrogen (273.75–788.25 kg/ha), P (20.1–59.65 kg/ha), potassium (182.25–346.5 kg/ha), and Zn (1.53–7.24 mg/kg). The study suggests that the combined application of liquid formulants of P. aeruginosa with FYM is advantageous, as FYM supports microbial growth by providing essential nutrients for mineralization. Moreover, liquid inoculants formulated with polyvinylpyrrolidone as an osmo protectant demonstrated enhanced shelf-life and mineral solubilization, contributing to improved biochemical properties in groundnut plants.