Two Distinct Soil Disinfestations Differently Modify the Bacterial Communities in a Tomato Field

Reductive soil disinfestation (RSD) and soil solarization (SS) were evaluated based on environ-mental factors, microbiome, and suppression of Fusarium oxysporum in a tomato field soil. Soil environmental factors (moisture content, electric conductivity, pH, and redox potential (RP)) were measured during soil disinfestations. All factors were more strongly influenced by RSD than SS. 16S rRNA amplicon sequencing of RSD- and SS-treated soils was performed. The bacterial com-munities were taxonomically and functionally distinct depending on treatment methods and pe-riods and significantly correlated with pH and RP. Fifty-four pathways predicted by PICRUSt2 (third level in MetaCyc hierarchy) were significantly different between RSD and SS. Quantitative polymerase chain reaction demonstrated that both treatments equally suppressed F. oxysporum. The growth and yield of tomato cultivated after treatments were similar between RSD and SS. RSD and SS shaped different soil bacterial communities, although the effects on pathogen sup-pression and tomato plant growth were comparable between treatments. The existence of patho-gen-suppressive microbes, other than Clostridia previously reported to have an effect, was sug-gested. Comparison between RSD and SS provides new aspects of unknown disinfestation pat-terns and the usefulness of SS as an alternative to RSD.