Growth and Yield of Onion (Allium cepa L.) by the Application of Plant Growth-Promoting Rhizobacteria

Aim: This study assessed the effects of vermicompost, the plant growth-promoting rhizobacteria (PGPR) Azospirillum, and the entomopathogenic fungus Beauveria bassiana on the growth and development of onion (Allium cepa L.). Methodology:The field experiment was conducted in a farmer's field located in Guayabal, Cauayan City, Isabela.This site has a flat surface and is suitable for planting upland crops.The soil texture is loamy with good drainage and is irrigated.The study evaluated combinations of vermicompost (ranging from 1.5 to 3 tons/ha), with or without Azospirillum and Beauveria bassiana, and compared these treatments to a control using the recommended rate of inorganic fertilizer.Treatments were arranged in a randomized complete block design (RCBD) with three replications.Results: Findings indicated that the combination of 3 tons/ha vermicompost, Azospirillum, and 3 liters of Beauveria bassiana significantly enhanced plant height, leaf length, and bulb diameter, outperforming the recommended rate of inorganic fertilizer.No significant differences were observed in leaf number and neck diameter across all treatments.The improved bulb yields were attributed to increased nutrient availability and biological activity resulting from the organic amendments, suggesting that this integrated approach could serve as a superior alternative to conventional fertilization practices. Conclusion:Based on the results, an integrated approach utilizing 3 tons/ha vermicompost, Azospirillum, and 3 liters of Beauveria bassiana offers a promising and potentially superior alternative to the recommended rate of inorganic fertilizer for enhancing key growth parameters and bulb yield in onion.