Effects of cultivation duration of the crop and growth stages on rhizosphere soil physicochemical properties, enzyme activities, and microbial communities of ginseng under forest

In this study, Illumina MiSeq sequencing of 16S and ITS2 rRNA genes were used to determine the dynamic changes in bacterial and fungal communities and soil properties and enzyme activities in rhizosphere soil of ginseng under forest after 5, 10 and 15 years of cultivation and different growth stages. Results showed that the changes were particularly prominent in 10-year-old ginseng under forest, and the trends of organic carbon, alkaline hydrolysed nitrogen, and available potassium were extremely similar in different duration of the crop, especially in the middle stage of rapid root growth, when soil nutrient consumption was severe, and soil enzyme activities of rhizosphere were significantly reduced. The observed changes in soil properties and enzyme activities caused by the cultivation duration of the crop and growth stage could be explained by the variations in the microbiome. The microbial composition of 10-year-old ginseng under forest has undergone significant changes, at the genus level, both Acinetobacter bacteria and Kazachstania fungi exhibited a higher abundance; the abundance of Bacillota (Firmicutes), and Candidatus udaeobacter with significantly lower abundance. This study initially revealed the changes in nutrient utilisation of ginseng under forest at different cultivation duration of the crop and different growth stages, as well as the regulatory role played by microbes in this process preliminarily. We consider 10 years to be a critical stage for the long-term cultivation of ginseng in the forest, during which it is more sensitive to environmental factors and may exhibit special dynamic changes affecting its growth and quality. This provides a reference for further precision planting and harvesting of ginseng under the forest.