2014 Fiscal Year Final Research Report
Application of nitrogen fixation and its effect on vegetation at highly disturbed low nutrient soil
| Project/Area Number |
24360198
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Partial Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Hydraulic engineering
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| Research Institution | Saitama University |
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Principal Investigator |
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Keywords | 窒素固定 / 河岸植生 / クズ / 洪水攪乱 / 根粒菌 / 河岸植生モデル / 河川樹林化 / 河川植生管理 |
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| Outline of Final Research Achievements |
Riparian zone is low in nutrients subjected to flood disturbances. Total nitrogen (N) contents and the fraction of 15N in soil were estimated using N stable isotope analyses and the amount of N-fixation was calculated. It was found that N-fixation rate decreases with increasing soil N concentration. An empirical formula was derived for a practical use. Initially, N accumulation in shoreline is very low due to the frequent inundation and disturbances. In the course of plant colonization, N enrichment occurs in the shoreline mostly by N-fixation. It was also found that biomass of shoreline herbs increases with soil N concentration; the relationship follows a simple empirical formula. Together with other influential factors for herb biomass and the recruitment and growth of trees, a prediction model for the riparian vegetation and soil nutrients were developed for the river management. The model was applied to several rivers and extremely good agreement was obtained with field surveys.
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| Free Research Field |
応用生態工学
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