The Effect of Biofumigation on the Microbiome Composition in Replanted Soil in a Fruit Tree Nursery

The imbalance of the soil microbiome is a primary indicator of ARD (apple replant disease). Biofumigation is a treatment that enables the restoration of microbiome balance. This study involved an analysis of the taxonomic and functional diversity of bacterial communities in replanted soil (ARD), in replanted soils with forecrops of French marigold (Tagetes patula L.), white mustard (Sinapis alba), and oilseed radish (Raphanus sativus var. oleifera), and in agricultural soil. The biofumigation treatment with phytosanitary plants changed the structure and abundance of the replanted soil microbiome in a fruit tree nursery. The count of operational taxonomic units (OTU) of the Proteobacteria, Bacteroidota, Patescibacteria, Chloroflexi, and Verrucomicrobiota phyla increased, whereas the count of the Firmicutes, Acidobacteriota, and Actinobacteriota phyla decreased. Biofumigation caused an increase in the content of some dominant bacterial genera, such as Flavobacterium, Massila, Sphingomonas, Arenimonas, and Devosia, in the replanted soil. Their presence in the soil may improve the growth of plants, induce their systemic resistance, and thus improve the production properties of soil with ARD. The research results led to the conclusion that the use of phytosanitary plants in nursery production can be an effective alternative to the chemical fumigation of soil.