Positive Microbial‐Enzyme Feedbacks on Soil Organic Carbon Enhance Understory Cultivation of <i>Paris polyphylla</i> Across Forest Types

ABSTRACT Understory imitation wild cultivation is widely used in production practice to improve the yield of Chinese medicinal plants. However, the impacts and mechanisms of cultivating medicinal plants under different forest types on soil organic carbon (SOC) pools, enzyme activities, and the diversity of cbh I‐functional microorganisms remain unclear. This study examined variations in soil SOC fractions, enzyme activities, and cbh I‐functional microbial communities, along with the interrelationships among these factors, in Paris polyphylla cultivation under the Moso bamboo forest, Chinese fir forest, and bamboo–Chinese fir mixed forest. The results indicated that the Chinese fir forest soil exhibited significantly higher contents of SOC (33.7 g kg −1 ), microbial biomass carbon (MBC) (361.2 mg kg −1 ), and water‐soluble organic carbon (WSOC) (176.6 mg kg −1 ), which were 27.2%, 73.7%, and 79.1% greater than those in the Moso bamboo forest (SOC: 26.5 g kg −1 , MBC: 207.9 mg kg −1 , WSOC: 98.6 mg kg −1 ), respectively. Furthermore, the mixed forest soil also showed significantly higher MBC (446.9 mg kg −1 ) and WSOC (118.5 mg kg −1 ) than the Moso bamboo soil, which were 115.0% and 20.2% higher, respectively. In addition, the activities of cellobiohydrolase, β‐glucosidase, and invertase in the soil of the Chinese fir forest were significantly higher than those of the bamboo forest, and the activities of cellobiohydrolase and invertase in the soil of the mixed forest were also significantly higher than that of the Moso bamboo. Correlation analysis revealed significant positive correlations between SOC, WSOC, and the activities of cellobiohydrolase, β‐glucosidase, and invertase, while MBC was significantly positively correlated with invertase activity. Mantel tests and Canonical correspondence analysis further highlighted soil pH, MBC, WSOC, and the activities of cellobiohydrolase and invertase as key environmental drivers of the cbh I microbial community structure. Interestingly, Moso bamboo forest soil supported a higher abundance of pathogenic fungi (e.g., Gaeumannomyces and Colletotrichum ), while Chinese fir forest soil was enriched with cellulose‐degrading bacteria (e.g., Irpex and Pyrenophora ), and mixed forest soil exhibited a relatively higher abundance of broad‐spectrum degraders (e.g., Clitopilus and Apiotrichum ). We conclude that Chinese fir and mixed forests have higher SOC storage, which can create a more favorable soil microenvironment for the cultivation of P. polyphylla . Due to the low SOC storage, the Moso bamboo forest is unfavorable for the growth and development of P. polyphylla .