Effects of Organo-Mineral Enriched Biochar Fertilizers on Physicochemical Characteristics and Bioactive Potential of Ginger ( Zingiber officinale )

Abstract Ginger (Zingiber officinale) is a globally consumed spice valued for its distinctive flavor and therapeutic properties, delivered by different bioactive constituents, including 6-gingerol. With increasing demand for functional foods and stringent international quality standards, producing ginger with consistent physicochemical quality and enhanced bioactive composition is a key challenge. Cultivation practices, especially growth media, play a decisive role in determining rhizome quality; however, integrated evaluations linking growth media to both compositional and functional attributes are limited. This study investigated the influence of different growth media on ginger quality and export suitability. Ginger was cultivated in compost and in two organo-mineral-enriched biochar fertilizer-based growth media (fish-based and green-based) at application rates of 1, 2.5, and 5 t ha–1. Growth media significantly influenced the compositional and functional attributes of ginger. Green-based enriched media at 5 t ha–1 produced the highest total phenolic (41.48 mg GAE g–1) and flavonoid contents (9.69 mg RE g–1), while fish-based enriched media at the same rate yielded the greatest antioxidant capacity (47.92 mmol Fe2+ g–1). The highest oleoresin content was reported in fish- and green-based-enriched media at 5 t ha–1, and fish-based media produced the best 6-gingerol yield. Fish 5 t ha–1 exhibited a significantly higher protein content, approximately 3-fold higher than in the control and compost treatments. Growth media strongly influence the physicochemical and bioactive properties of ginger. Fish and green-based biochar media, particularly at higher application rates, enhance functional quality and bioactive accumulation, providing a practical strategy for producing premium-grade ginger suitable for export markets.