Relationships between Rhizosphere Environments and Growth of 10-Year-Old Wild-Simulated Ginseng

Wild-simulated ginseng (WSG, Panax ginseng C.A. Meyer) must be cultivated in mountainous forests without installation of artificial facilities or treatment of chemicals. Because cultivation of these medicinal plants requires a long-term period, soil properties and rhizobacteria are known as major factors affecting their growth. This study was aimed to investigate correlations of soil bacterial community with soil chemical properties and growth of 10-year-old WSG. Most of the growth characteristics of WSG were higher in southern region than in northern regions, while leaflet length and leaflet width of WSG were higher in northern regions. In all WSG cultivation sites, the most dominant phyla were Proteobacteria and Acidobacteria in the bacterial community. In Principal component analysis (PCA), soil bacterial community was affected by exchangeable cations (calcium, magnesium), soil pH, total nitrogen, cation exchange capacity, and organic matter. Soil pH was the most effective factor in this study because all studied sites were acidic soils. In spearman's coefficient analysis, 9 of 13 growth characteristics of WSG showed significantly positive correlation with the relative abundance of Actinobacteria, while rhizome length and number of rootlets showed significant negative correlations with population of Acidobacteria. Therefore, growth characteristics of WSG in different cultivation sites can be affected by various soil environmental factors. These results can help foresters find suitable cultivation sites for WSG.