Mei Han

Soil, as the foundation for the survival of understory ginseng, directly impacts its growth and development. However, studies focusing on the role of soil in determining the quality of understory ginseng are limited. This study examines the relationship between quality and yield of 5-, 9-, and 17-year-old understory ginseng and their soil microbiota. The results indicate that with the increase in growth years, the overall biomass of understory ginseng generally shows an upward trend, while its quality slightly decreases at 9 years. Compared to the other two growth years, the soil from 9-year-old ginseng shows lower enzyme activity and pH and a higher abundance of pathogens. The 17 years soil has higher OM and AHN content, along with increased abundance of denitrifying and nitrogen-reducing bacteria. Correlation networks reveal that AK significantly influences ginsenoside content, while AP and AHN are more closely related to soil microorganisms. Compared with other types of ginsenosides, ginsenosides Rh2 and Rd are affected by a greater variety of soil microorganisms and chemical factors. As growth years increase, the changes in ginseng quality, soil nutrients, and soil microbiota do not follow a single linear trend; instead, there appears to be a bottleneck phase at certain intermediate stages.