Plant Performance and Soil Fungal Community Impacts of Enhancing Dioscorea opposita with Spraying Foliar Fertilizer with Different Nutrient Element Combinations

Foliar fertilization, an effective method to regulate plant nutrition has attracted much attention. In this study, the effects of different foliar fertilizers (F1: NPK formulation, F2: NPK+Fe-Mn-Zn formulation, F3: Fe-Mn-Zn formulation, and CK: deionized water) on plant growth, chemical composition, rhizosphere soil properties, and fungal community of Dioscorea opposita Thunb. were assessed by a field plot experiment. Rhizosphere fungal community was examined via Illumina MiSeq sequencing of ITS2 rRNA genes. Spraying foliar fertilizer directly affected the growth and chemical content of the plant, which depends on different foliar fertilizers. Ascomycota and Moraxella were the dominant fungal phyla. Nutrient elements were the main factors affecting fungal composition, and soil microelements positively influenced soil fungi, while soil macroelements negatively influenced soil fungi. Macroelement foliar fertilizer affected soil fungi by directly affecting the growth parameters and macroelement content of the plant or by directly affecting soil properties, while microelement foliar fertilizer affected soil fungi by directly affecting the microelement content of the plant or by directly affecting the soil pH and organic matter content. These factors were involved in the formation of a "leaf-root-soil microbe" conduction system similar to the "brain-gut-microbe" axis. Our results provide a basis for the application of foliar fertilizer in the cultivation of medicinal plants.