Soil Fusarium graminearum is inhibited by combined application of crop residues and an organic stimulant

Application of crop residues combined with an organic stimulant has been previously proven to promote residue decomposition through stimulating microbial decomposers, while little is known about whether the residue-borne Fusarium graminearum (Fg) from the soil concurrently changed. A one-year wheat field experiment was conducted to investigate how the stimulant-induced changes in soil properties, bacterial and fungal community compositions affected the soil Fg abundance. Four treatments were designed including (1) combined application of crop residues (R) and an organic stimulant (S) (RS), (2) only R was applied (R), (3) only S was applied (S), and (4) an unamended control (R0S0). No Fg was determined from the R0S0 soil. Among the other three treatments, the R and S had similarly highest levels of the soil Fg abundance, with the average values being 136.71 % higher than that from the RS treatment, which was mainly regulated by declining soil pH and the enrichment of the fungal taxa associated with crop residue decomposition and biocontrol induced by increasing DOC in the RS treatment. Likewise, the FHB disease incidence from the RS treatment was 9.77 % lower than that from the R and S. We demonstrated that combination application of crop residues and an organic stimulant showed effectiveness in reducing the Fg abundance in soil and FHB disease incidence in wheat due to the stimulant-induced changes in soil properties and shifts in composition of the fungal community rather than the bacterial community. Our results provide novel insights on FHB prevention and control in practical agricultural production.