Effects of biogas residue addition, as cultivation substrate, on ginseng growth

The effects of biogas residue as a substrate on ginseng growth and its feasibility for ginseng cultivation are unclear. The present study used biogas residue at different concentrations and maturity levels to cultivate ginseng. The biological characteristics of ginseng, soil physiochemical indices, and ginseng and soil microbial communities were investigated. The results showed that with increasing ginseng content and maturity, the total fresh weight, total length and saponin content significantly increased. The enzyme activities of soil, NO3--N, and available phosphorus also increased. The microbiome analysis revealed that with the addition of biogas residue, microorganisms related to plant growth promotion, such as Chloroflexi, Gemmatimonadota and Mortierellomycota, were more common in the plant or rhizosphere soil. The results based on the co-occurrence network showed that the structure of the bacterial community was more stable than that of the fungal community with increasing biogas residue content. Our results indicated that biogas residue could be used as a ginseng cultivation substrate and promote growth.