A Novel Approach to Address Lead Exceedance Issue in the Geographical Indication Product Laifeng Ginger (Zingiber officinale cv. Fengtoujiang): Co-Application of Organic Fertilizer and Compound Fertilizer

Laifeng ginger (Zingiber officinale cv. Fengtoujiang) is a famous Geographical Indication (GI) ginger variety, which grows specifically in Laifeng County, Hubei, China. In recent years, it faced a serious food safety issue of lead (Pb) exceedance in the rhizomes even though the Pb content in the soil remains at a safe level. This problem severely hinders the local ginger’s market growth. In the present study, a field study across 37 Laifeng ginger farms revealed a connection between the occurrence of Pb exceedance and the choices of fertilizers. Cultivation experiments demonstrated that with more organic fertilizer (OF) applied, the Pb of rhizome effectively declined, and the branching and longitudinal growth were enhanced. The OF application facilitated Pb translocation from rhizomes to stems and leaves. Furthermore, we showed that OF improved the soil properties by altering the pH and the composition of soil microbial communities at the genus level, which was likely to be associated with reduced the Pb content in the ginger rhizomes. This research tackles the critical industry issue of Pb exceedance in Laifeng ginger, providing a basis for the fertilization of root and tuber plants with excessive heavy metal levels, and establishes a foundation for sustainable GI product development.