Effects of Vermicompost and Vermicompost Tea on Ginseng Production and Soil Microbial Populations in Northcentral Wisconsin.

“Wisconsin-Grown” ginseng (Panax quinquefolius) is increasing in demand across the globe, but commercial ginseng production currently involves the heavy application of pesticides, which can have adverse impacts on human and environmental health. The purpose of this study is to evaluate the benefits of using vermicompost and vermicompost tea in commercial ginseng production. We hypothesized that compost -derived amendments would promote plant growth by enhancing beneficial microorganism populations, while inhibiting soil-borne phytopathogens.

Our experiment included replicated plots with three locations, four rates of vermicompost amendment, and presence/absence of vermicompost tea application using a randomized complete block and split plot design. We measured plant growth and fitness using individual root mass, root mass yield per area, and mass of berries over three growing seasons in Marathon County, WI. Rhizosphere soil samples were collected during the final two growing seasons and subjected to DNA extraction for characterization of plant-associated soil microbial communities.

A significant increase in total root mass yield was found when vermicompost tea was applied, but no significant difference in root mass of individual plants was observed. Additionally, it was found that the average mass of berries produced decreased when vermicompost tea was applied.

The composition of bacteria and fungi in ginseng rhizosphere samples is being determined by sequencing genetic fragments from the 16S rRNA and ITS, respectively. We will assess the ability of microbial community composition to explain the relationship between ginseng fitness and use of vermicompost-derived amendments.