Panax notoginseng Planted Under Coniferous Forest: Effects on Soil Health and the Soil Microbiome

The agroforestry system provides a new option for P. notoginseng cultivation. However, the effects on soil health and microbial communities are still incomplete when monoculture coniferous forests are converted to P. notoginseng–pine plantations. To assess soil health, samples from five P. notoginseng–pine plantations were collected, including healthy plants and root-diseased plants, as well as plantation control soil. The samples were analyzed for physical, chemical, and biological aspects and soil microbial communities. Our results suggested that P. notoginseng planted under pine forest was more conducive to increased microbial biomass carbon, soil dissolved organic nitrogen, particulate organic nitrogen, and soil enzyme activities compared with uncultivated control soil. A quantitative assessment of soil health demonstrated that the comprehensive soil quality index (SQI) of P. notoginseng-cultivated soil exhibited marked increases of 79.41% and 119.85% in comparison with the control soil. The observed alterations in soil characteristics could be attributed to variations in the soil microbiome. This implies that changes in SQI positively regulate bacterial and fungal abundance in P. notoginseng–pine agroforestry ecosystems mainly through biological properties. This comprehensive SQI assessment helps to guide the cultivation of P. notoginseng under forest and improve soil quality for P. notoginseng–pine agroforestry ecosystems.