2022 Fiscal Year Final Research Report
A new mechanism by which nitrogen deposition suppresses soil organic matter decomposition
Project/Area Number |
20K12147
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 63010:Environmental dynamic analysis-related
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Research Institution | Shinshu University |
Principal Investigator |
Kunito Takashi 信州大学, 学術研究院理学系, 教授 (90304659)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 土壌 / リン / 有機物分解 / 土壌酵素 |
Outline of Final Research Achievements |
This study tested the hypothesis that a decrease in relative P availability due to N deposition in forest ecosystems would cause P limitation of less-competitive lignin-degrading microorganisms, which would reduce ligninase activity and suppress soil organic matter decomposition. The concentration of available P was higher in the N-added samples than in the control samples. Addition of N decreased ligninase activity in some samples, while in others, N addition increased ligninase activity. This suggests that N addition does not decrease P availability, but decreases ligninase activity in some soils through other mechanisms. The results also indicate that N addition does not necesarily decrease ligninase activity in soils.
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Free Research Field |
土壌学
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Academic Significance and Societal Importance of the Research Achievements |
人為起源の過剰な窒素の流入により土壌有機物分解が抑制され、森林生態系の炭素貯留量が増加し、地球システムにおける炭素循環にも影響が及ぶ可能性が指摘されている。窒素流入によって微生物分解が抑制されるメカニズムとして、リグニン分解酵素活性の低下と微生物バイオマスの減少とが提唱されている。本研究では、リン利用性の低下と土壌酸性化以外の機序により、窒素流入によりリグニン分解酵素活性が低下する土壌が存在することが示唆された。また今後予想される窒素流入量では、対象とした全ての土壌において窒素流入が有機物分解に与える影響は小さい可能性が示唆された。
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