Artemisia argyi leaf powder improves soil properties and recruits Sphingobium bacteria to promote the growth and yield of Pinellia ternata.

Abstract

Recent research has reported the strong herbicidal activity of Artemisia argyi leaf powder (AALP), indicating its high potential for use as an environmentally friendly weed management solution for ecological agriculture. However, AALP's impacts on soil physicochemical properties and microbial communities have remained uninvestigated. This study explores these effects through pot experiments assessing the AALP's efficacy in weed suppression and its ability to promote the growth of Pinellia ternata, a plant utilized in traditional Chinese medicine. The results demonstrate that a 10% concentration of AALP suppressed nearly 100% of all weeds. Additionally, AALP treatments at 2.5%, 5%, 7.5%, and 10% concentrations increased P. ternata yields by 29.79%, 24.76%, 35.67%, and 31.00%, respectively. A soil analysis revealed that AALP enhanced soil fertility by increasing the contents of nutrients such as SOM, AN, AP, AK, Ca, Fe, Mn, and Zn, as well as the enzyme activity of CAT, ACP, UE, and SC, creating an optimal growth environment for P. ternata. In addition, AALP significantly increased the PA (phenolic acid) content in soil, which is a key factor in inhibiting weed germination and growth. Furthermore, a microbial community structure analysis indicated an enrichment of Actinobacteriota and Bacteroidota after AALP treatment, with notable increases in the growth-promoting bacteria Sphingobium and Flavobacterium. A permutational multivariate analysis of variance (PERMANOVA) based on the Bray-Curtis distance reaveled that all of the tested soil properties were significantly correlated with changes in bacterial community composition except for pH. Further two-factor correlation network analysis identified AN, Zn, SC, and PA as key environmental factors. Finally, the Sphingobium sp. strain AFR15, isolated from AALP-treated soil, exhibited significant growth-promoting effects on P. ternata. After inoculation with Sphingobium sp. strain AFR15 for one month, the heights of P. ternata were increased significantly. The leaf length and leaf width of P. ternata were also positively correlated with the treatment concentration of AFR15, and the chlorophyll contents of the leaves also increased. This results highlighted Sphingobium sp. strain AFR15's potential as a specialized microbial fertilizer in crop yield increased. In conclusion, AALP applications not only control weeds but also promote P. ternata growth by improving soil physiochemical properties and fostering beneficial bacterial allies. These findings lay the groundwork for future research and promote the use of AALP in ecological agriculture.