Enhancing Sustainable Cultivation of Organic Bell Pepper through Fulvic Acid (FA) Application: Impact on Phytochemicals and Antioxidant Capacity under Open-Field Conditions

Fulvic acid (FA) is an eco-friendly solution for reducing the reliance on agrochemicals and enhancing crop quality. The study aimed to investigate the impact of soil and foliar application of FA on the phytochemical content and antioxidant properties of organically grown bell peppers at both the green and red stages. Bell pepper cv. Revolution was grown under open-field conditions at the certified organic farm at Tennessee State University, Nashville, with nine treatments and three replications. FA was applied as a soil drench and foliar spray at four different rates (0, 2.3, 5.5, 7.8, 10.9 mL L −1 ). The fruits were harvested 55 days (green stage) and 86 days after transplantation (red stage). The study showed significant differences ( p ≤ 0.05) between the treatment and maturation stage. The foliar treatment of 7.8 mL L −1 resulted in the highest phenolic content in green bell peppers. The highest total flavonoid content in red bell peppers was achieved with a soil treatment of 7.8 mL L −1 . Additionally, the highest level of vitamin C in red bell peppers occurred with a soil concentration of 5.5 mL L −1 . In conclusion, applying FA as a biostimulant can enhance the quality of organically grown bell peppers, offering promising opportunities for sustainable agricultural practices.