The chemodiversity of paddy soil dissolved organic matter is shaped and homogenized by bacterial communities that are orchestrated by geographic distance and fertilizations

Understanding the soil dissolved organic matter (DOM) chemodiversity and its interaction with microbes is crucial to comprehend the biogeochemical processes in soil. In this study, ultrahigh-resolution fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was employed to in detail characterize the DOM chemodiversity at a molecular level. The variation of the DOM chemodiversity from four agro-ecological experimental sites (paddy fields) subjected to different long-term fertilizations across different distance-points was evaluated. Geographic distance had a greater impact on DOM chemodiversity than anthropogenic fertilization. Distance-decay analysis showed that the dissimilarity of the DOM chemodiversity significantly increased with the increase in geographic distance. Long-term organic fertilizations homogenized the DOM chemodiversity as it made lipid-like compounds more similar regardless of geography. A network analysis combining DOM chemodiversity and bacterial community composition showed the significant interactions between bacteria species and DOM molecules. Variable partitioning analysis (VPA) showed that the bacterial community diversity dictates the soil DOM chemodiversity and not vice versa. Geographic distance indirectly affects the soil DOM chemodiversity by shaping the bacterial community.