Abstract: A 13-year-old apple orchard on the Longdong Loess Plateau was selected as the site for this study. High-throughput sequencing was used to analyze the soil fungi community structure and the genera present in the 0-10 cm soil layer when planted with three different forage species (orchard grass, white clover, and lucerne). The results showed that the alpha diversity of soil fungi was increased by 17.4%, 18.6%, and 27.0% in the orchard grass, white clover, and lucerne plantings, respectively, compared with that in the control (clean tillage). At the phylum level, the soil fungi community mainly comprised Ascomycota, Zygomycota, Basidiomycota, and Glomeromycota. The relative abundance of Zygomycota under the three forage species was increased by 196.2%, 169.8%, and 126.9%, respectively, compared with that in the control. At the genus level, the relative abundance of Fusarium in soil was higher in the three forages than in the control, and the relative abundance of Phoma in soil was higher in the white clover and lucerne plots than that in the control. The soil planted in orchard grass had abundant Thermomyces, which are associated with protein and carbohydrate degradation. Stachybotrys and Actinomucor, which secrete catabolic enzymes that decompose plant fibers and hemi-fibers, were present in the soil of the white clover treatment. The soil in the lucerne treatment contained Cladosporium and Botryosphaeria.

Key words: apple orchard, grass-planting patterns, soil fungi, community characteristics