2022 Fiscal Year Final Research Report
Carbon and nitrogen dynamics inside of soil aggregates
| Project/Area Number |
20K21295
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 38:Agricultural chemistry and related fields
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| Research Institution | National Agriculture and Food Research Organization |
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Principal Investigator |
Wagai Rota 国立研究開発法人農業・食品産業技術総合研究機構, 農業環境研究部門, 上級研究員 (80456748)
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| Co-Investigator(Kenkyū-buntansha) |
長尾 眞希 (浅野眞希) 筑波大学, 生命環境系, 助教 (80453538)
井上 弦 長崎総合科学大学, 総合情報学部, 准教授 (30401566)
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| Project Period (FY) |
2020-07-30 – 2023-03-31
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| Keywords | 土壌団粒 / 炭素循環 / 窒素循環 / 土壌有機物 / 同位体生態学 / 生物地球化学 / 土壌炭素隔離 / 物質循環 |
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| Outline of Final Research Achievements |
Surface soils where plants grow typically have aggregate structure. While soil is the biggest terrestrial reservoir of C & N and their cycles are largely driven by microbes, how soil aggregate structure is functionally linked to microbial C & N transformation remain virtually unknown. By combining soil incubation with isotope tracers, soil physical fractionation, and chemical characterization of each fraction (e.g., EA, SEM, and NanoSIMS), we showed that the fate of microbially-metabolized C & N was strongly regulated by aggregate hierarchy. We also examined the long-term fate of C & N in organo-mineral aggregates using the two buried Andisol horizons (burial age: ca 500 & 4600 yrs). We found significant linear relationship between C and pyrophosphate-extractable Al and Fe across all horizons, layers, and the size fractions we obtained after maximum dispersion of aggregates. We also assessed the effect of soil redox regimes on the interaction of organic matter with Al and Fe.
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| Free Research Field |
土壌科学
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| Academic Significance and Societal Importance of the Research Achievements |
陸上最大の炭素（C）や窒素（N）プールである土壌において、微生物によるCN代謝は物質循環の要であるが、これまでの研究では、微生物の住み家であり土壌諸反応の場である団粒構造はほとんど無視されてきた。また、団粒や土壌粒子の最表面（反応面）で生じる有機物と無機物の相互作用について知見に乏しい。同位体標識CNのトレーサー実験、同位体顕微鏡分析、これまで我々が培ってきた団粒階層構造の評価手法を組み合わることで得られた本成果は、CN代謝を団粒構造という物理環境に則して定量評価する新手法であり、土壌CN動態予測モデルの高度化、更に土壌における物理学・化学・生物学の融合に向けた重要な成果と言える。
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