AGRICULTURALFARMLAND

Soil health plays a crucial role in agricultural productivity, influencing microbial diversity, nutrient availability, and overall plant growth. The presence of plant growth-promotingbacteria(PGPB) in soil enhances crop yield by facilitating nitrogen fixation, phosphate solubilization, and the production of essential phytohormones This study focused on the isolation of PGPBfromselected farmlands in Oluku and an assessment of the physicochemical properties of thesoils. Bacterial counts varied across the farms, with the highest recorded in Farm8 (40.60±5.94×10⁴ CFU/ml) and the lowest in Farm 6 (11.20±0.57 × 10⁴ CFU/ml). Nine bacterial species wereidentified, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichiacoli, Enterobacter aerogenes, and Bacillus pumilus. Among these, E. coli exhibited all four keyplant growth-promoting traits: nitrogen fixation, phosphate solubilization, ammonia production, andindole-3-acetic acid (IAA) production, making it the most versatile isolate. The physicochemical analysis of soil samples revealed pH values ranging from slightly acidic to nearly neutral (5.64–6.42). Electrical conductivity, organic matter, and organic carbon contents varied significantly, with Farm 2 exhibiting the highest values (EC: 873.00 ± 43.65 μS/cm, OM: 4.78 ± 0.24%, OC: 8.24 ± 0.41%). Essential nutrients such as phosphorus, nitrogen, potassium, calcium, andmagnesium were also found in varying concentrations across the farmlands. Heavymetal analysis indicated the presence of iron (453.72–637.84 mg/kg), zinc (65.79–87.52 mg/kg), lead(2.87–4.69 mg/kg), and copper (21.45–28.75 mg/kg), with potential implications for soil qualityand crop safety. These findings highlight the significance of beneficial soil bacteria in improvingplant growth and emphasize the need for sustainable soil management practices. Regularmonitoring of soil nutrients and heavy metal levels is essential for maintaining soil fertilityandensuring safe agricultural production.