Bio-fertilizer as a pathway to minimize nitrate leaching from chemical fertilizer in high yield peppermint production

Abstract

The contamination of Iran's underground water sources with nitrate from chemical fertilizers poses a significant health risk to communities reliant on this essential water source. This study investigates the benefits of organic alternatives, such as vermicompost and bio-fertilizers, in sustainable peppermint production. The aim is to foster environmentally friendly agricultural practices and enhance soil health. Multiple fertilizer treatments were examined for their impact on peppermint growth, essential oil (EO) content, and bioactive properties. Results show that incorporating vermicompost with chemical or bio-fertilizers significantly improves plant height, dry leaf weight, leaf number, and drug fraction by 18.6%, 82%, 27.5%, and 25%, respectively. Vermicompost application leads to a remarkable 100% increase in EO content and a substantial 31.5% rise in menthol percentage compared to other treatments. Furthermore, the study reveals that enhanced menthol production coincides with improved antibacterial and antifungal properties of the plant extract and EO. Treatments with bio-fertilizers demonstrate a significant 23.4% increase in menthol percentage compared to the control group. Vermicompost usage also boosts the total phenolic, flavonoid, and anthocyanin content, along with the antioxidant capacity by 5%–17%. Replacing chemical fertilizers with vermicompost and bio-fertilizers shows notable improvements in peppermint production. These findings underscore the significance of employing organic fertilizers as a means to advance sustainable agricultural practices, mitigate health hazards linked to water contamination, and optimize the cultivation of peppermint as a globally valuable medicinal plant.