2022 Fiscal Year Final Research Report
Reactive transport modeling with carbon and nitrogen cycling for micro-aggregate up to root-zone scales in paddy and upland fields
Project/Area Number |
20H03098
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 41030:Rural environmental engineering and planning-related
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Research Institution | Mie University |
Principal Investigator |
Toride Nobuo 三重大学, 生物資源学研究科, 教授 (70212074)
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Co-Investigator(Kenkyū-buntansha) |
渡辺 晋生 三重大学, 生物資源学研究科, 教授 (10335151)
坂井 勝 三重大学, 生物資源学研究科, 准教授 (70608934)
橋本 洋平 東京農工大学, (連合)農学研究科(研究院), 准教授 (80436899)
徳本 家康 佐賀大学, 農学部, 准教授 (80445858)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 水田 / 畑 / 有機物分解 / 窒素循環 / 炭素循環 / 反応移動モデル |
Outline of Final Research Achievements |
In order to predict the fate and transport of carbon and nitrogen in a reduced paddy field, we modified the carbon and nitrogen cycling model based on the LEACHM code. SOM decay processes from organic carbon to biomass carbon, humus carbon, and carbon dioxide were described using first-order kinetics. When oxygen was available in an aerobic condition, O2 was used to produce CO2 as an electron accepter. When O2 availability is low, other electron acceptors such as NO3-, Mn4+, Fe3+, SO42-, were used depending on the redox potential. Decomposition of Org-N was related to the carbon cycle using the C/N ratio. Furthermore, cation and anion exchange reactions were included with the permanent negative charges and the pH dependent variable charges. The carbon and nitrogen cycling model described with PHREEQC was linked with HYDRUS-1D using the HP1 code. Various nitrogen and carbon transport scenarios were demonstrated for the application of organic matter to a saturated paddy soil.
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Free Research Field |
土壌物理学
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Academic Significance and Societal Importance of the Research Achievements |
本研究により,水分不飽和の畑から湛水状態の水田までの好気・嫌気有機物分解と窒素炭素の形態変化と土中の移動を表すシミュレーションプログラムを構築した.特に,水田土中の嫌気分解と還元物質の形態変化を定量的に表現し,陽イオン交換,陰イオン交換,土の緩衝作用を含めた溶質移動モデルは他に例がなく,開発の意義は大きい.今後は,さらにモデルの実証実験を行うために,下端圧力が制御可能な重量ライシメータの開発と検討を行った.
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