Organic\nCarbon Amendments Affect the Chemodiversity\nof Soil Dissolved Organic Matter and Its Associations with Soil Microbial\nCommunities

Abstract

The\n“4 per mil” initiative recognizes the pivotal\nrole of soil in carbon resequestration. The need for evidence to substantiate\nthe influence of agricultural practices on chemical nature of soil\ncarbon and microbial biodiversity has become a priority. However,\nowing to the molecular complexity of soil dissolved organic matter\n(DOM), specific linkages to microbial biodiversity have eluded researchers.\nHere, we characterized the chemodiversity of soil DOM, assessed the\nvariation of soil bacterial community composition (BCC), and identified\nspecific linkages between DOM traits and BCC. Sustained organic carbon\namendment significantly (<i>P</i> < 0.05) increased total\norganic matter reservoirs, resulted in higher chemodiversity of DOM\nand emergence of recalcitrant moieties (H/C < 1.5). In the meantime,\nsustained organic carbon amendment shaped the BCC to a more eutrophic\nstate while long-term chemical fertilization directed the BCC toward\nan oligotrophic state. Meanwhile, higher connectivity and complexity\nwere observed in organic carbon amendment by DOM–BCC network\nanalysis, indicating that soil microbes tended to have more interaction\nwith DOM molecules after organic matter inputs. These results highlight\nthe potential for organic carbon amendments to not only build soil\ncarbon stocks and increase their resilience but also mediate the functional\nstate of soil bacterial communities.