Estimation of nitrogen loss from forested watersheds by coupling a plant-soil N cycling model and a hydrological model

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K15286
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Forest science
• Research Institution: Kyoto University
• Principal Investigator: Fukushima Keitaro 京都大学, 生態学研究センター, 研究員 (60549426)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 渓流水質 / 窒素流出 / 攪乱応答モデル / 下層植生 / 河床湧水 / 窒素沈着

Outline of Final Research Achievements

This study reveals that the nitrogen accumulation by understory vegetation and nitrogen contamination from outside the watershed can be important factors contributing stream nitrate export in forest ecosystems. I tried to apply water and nitrogen budget data over multiple years to the PnET-CN and TOPMODEL in order to simulate nitrogen export from forested watersheds. Gaps between observed and simulated values suggested that the process during rainfall event should be improved. Detailed analysis for these factors and process are necessary to construct sophisticated water-nitrogen budget model.

Free Research Field

森林生態系生態学

Academic Significance and Societal Importance of the Research Achievements

本研究では，これまで森林の物質循環研究で重視されてこなかった下層植生の重要性と，集水域外からの物質流入に関して，長期に渡る水質調査と，広域的な水質調査の両面から実証したことが最大の学術的意義である。また，攪乱応答型の水・窒素流出モデルの構築に向けて，実測データを既往の物質循環モデル（PnET-CN）や流出モデル（TOPMODEL)に適用を試み，精度向上のための課題を洗い出すことができ，今後の研究の展開に資する成果を供出できた。