2021 Fiscal Year Final Research Report
Fate of frozen soil layer under environmental changes, and the dynamics of water and solute in soil under the frozen soil
| Project/Area Number |
17H03888
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Rural environmental engineering/Planning
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| Research Institution | Mie University |
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Principal Investigator |
Watanabe Kunio 三重大学, 生物資源学研究科, 教授 (10335151)
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| Co-Investigator(Kenkyū-buntansha) |
武藤 由子 岩手大学, 農学部, 准教授 (30422512)
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| Project Period (FY) |
2017-04-01 – 2022-03-31
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| Keywords | 凍土 / 気候変動 / 溶質移動 / 浸潤 / 地表面過程 / 有機物分解 / 硝化 / 凍上 |
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| Outline of Final Research Achievements |
To understand soil freezing and thawing under various moisture and temperature environments, laboratory experiments and numerical analysis were performed. Solute transport from unfrozen to frozen soil was verified, and change in the soil freezing point and freezing rate depending on the solute transport were clarified as well as condensation of solute into unfrozen water in the frozen soil. When water infiltrate into dry frozen soil, five temperature regions were appeared. And, organic decomposition and nitrification in soil under the frozen soil was investigated. It was suggested that soil water flow enhance the mineralization and nitrification in the soil. For frost heaving, effects of anisotropy of groundwater supply route to freezing front, and solute and foreign substances in the soil were elucidated. We also proposed ideas to improve soil freezing model, such as non-equilibrium freezing and thawing of soil water and feasible surface boundary conditions.
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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 |
凍結融解によって生じる土中の水分移動は、栄養塩・化学汚染物質の移動や、凍土層下の微生物活性を律則し、農地の水分・施肥管理や地耐力に影響を及ぼすだけでなく、硝酸態窒素の地下水帯への流出や温室効果ガスの地表への放出を誘起する。温暖化に伴う土壌凍結深分布や降水パターンの変化が顕在化しつつある現在、農業の持続的展開、気候変動への適応、生態環境との調和、省エネルギーの観点から、環境変化に伴う土壌凍結層の盛衰と付随する物質移動の理解が求められている。本研究で明らかになった知見や蓄積された実験データ、改良されたモデルはこうした理解を大いに進めるものである。
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