{
  "abstract": "Introduction: Long-term organic fertilization is known to improve soil fertility, but the mechanisms by which it enhances soil nitrogen (N) availability, particularly the relative importance of direct nutrient stimulation versus diazotroph-mediated pathways, remain unclear.\n\nMethods: We examined the effects of four fertilization regimes (without fertilizer, CK; 100% chemical fertilizer, NPK; rice straw plus chemical fertilizer, RS; and 30% organic manure plus 70% chemical fertilizer, OM) on soil properties, diazotrophic community composition ( nif H gene amplicon sequencing), N ₂ fixation activity (potential BNF and nitrogenase concentration), and soil N pools (NH ₄ ⁺ –N, NO ₃ ⁻ –N, and MBN) in a 37 year double-cropping paddy rice field experiment.\n\nResults and discussion: Long‑term organic fertilization, particularly OM, significantly increased soil organic carbon, total nitrogen and microelements (Mo, Fe, V and AMo). Relative to CK, OM treatment increased soil potential BNF rates by 342% and nitrogenase concentration by 178%, and maintained the highest soil inorganic nitrogen and MBN pools. Soil diazotrophic community composition (PCoA Axis1), rather than alpha diversity or nif H gene abundance, was the strongest correlate of potential BNF rates ( r = 0.70, p < 0.001) and nitrogenase concentration ( r = 0.85, p < 0.001). Partial least squares path modeling revealed that soil nutrients influenced soil N availability through dual pathways: a dominant direct effect on soil N fixation potential (0.734, p = 0.002), and a significant indirect effect mediated by soil diazotrophic community composition and N fixation activity (0.330). The model explained 98.8% of the variance in soil N availability with a goodness of fit of 0.842. In contrast, soil microelements showed negligible direct or indirect effects. These findings demonstrate that long-term organic fertilization enhances paddy soil N availability through coupled mechanisms: a dominant direct stimulation of N fixation by increased carbon and nutrient availability, complemented by a secondary pathway involving shifts in diazotrophic community composition and their concomitant N fixation activity. This study provides mechanistic evidence that sustaining soil N fertility in intensive rice agriculture depends on both adequate organic nutrient inputs and the maintenance of functional diazotrophic communities.",
  "abstract_shown": true,
  "affiliations": [
    "Hunan Cultivated Land and Agricultural Eco-Environment Institute",
    "Yuelushan Laboratory"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Li Wen"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Chao Li"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Kaikai Cheng"
    },
    {
      "affs": [
        0
      ],
      "name": "Lihong Shi"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Lingling Liu"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Shijie Qin"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Ke Wang"
    },
    {
      "affs": [
        0
      ],
      "name": "Peng Jiang"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Haiming Tang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ee8bhfzscxtv8.bib",
  "cited_by": 0,
  "doi": "10.3389/fmicb.2026.1923757",
  "fulltext_url": "https://europepmc.org/articles/PMC13687272",
  "id": "ee8bhfzscxtv8",
  "issns": [
    "1664-302X"
  ],
  "landing_url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1923757/full",
  "language": "eng",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1111|Soil Carbon and Nitrogen Dynamics"
    ]
  ],
  "openalex": "W7220910801",
  "pdf_url": "https://europepmc.org/articles/PMC13687272?pdf=render",
  "pmcid": "PMC13687272",
  "pmid": "42922982",
  "published": "2026-10-08",
  "publisher": "Frontiers Media SA",
  "ris": "https://research.draconitic.com/paper/ee8bhfzscxtv8.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:12Z",
      "native_id": "10.3389/fmicb.2026.1923757",
      "source": "crossref",
      "url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1923757/full"
    },
    {
      "first_seen": "2026-10-30T12:20:33Z",
      "native_id": "MED:42922982",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42922982"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:1111|Soil Carbon and Nitrogen Dynamics",
      "subfield": "hydrology-soils"
    }
  ],
  "title": "Long-term organic fertilization enhances paddy soil nitrogen availability through direct nutrient stimulation and complementary diazotroph-mediated pathway",
  "title_text": "Long-term organic fertilization enhances paddy soil nitrogen availability through direct nutrient stimulation and complementary diazotroph-mediated pathway",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:20:33Z",
  "url": "https://research.draconitic.com/paper/ee8bhfzscxtv8",
  "venue": "Frontiers in Microbiology",
  "versions": []
}