2007 Fiscal Year Final Research Report Summary
Environmental Preservation Strategy through the Optimization of Homeostatic Functions of Soils
| Project/Area Number |
17380139
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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 |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MIYAZAKI Tsuyoshi The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor (00209892)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Taku Tokyo University of Agriculture and Technology, Dept of International Environmental & Agricultural Sciences (TEAS), Associate Professor (40237730)
MIZOGUCHI Masaru The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor (00181917)
SEKI Katsutoshi Toyo University, Faculty of Business Administration, Associate Professor (40313069)
FUJIKAWA Tomonori The University of Tokyo, Department of Biological and Environmental Engineering, Assistant Professor (60361573)
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| Project Period (FY) |
2005 – 2007
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| Keywords | homeostasis / water cycle / carbon cycle / thermal cycle / salt accumulation / priming effect / environmental preservation / 環境保全戦略 |
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| Research Abstract |
The homeostatic function of soils is defined as the tendency of stable equilibrium in physical, chemical and biological conditions of soils. If the homeostatic function of soils is reduced, the natural environment may be damaged more by the global climate change and by the anthropogenic disturbance of environment On the other hand, if the homeostatic function of soils is induced, the natural environment may be more stable and sustainable. The purpose of this study was to find the environmental preservation strategy by optimizing the homeostatic functions of soils. The results of this study are summarized into three categories.
1. Homeostatic function of soils on water cycles Through the elaborate investigation of the relation between the salt accumulation on the land surface and the fluctuation of shallow ground water level in north-east part of China, we discovered that some few mm supply of water into the clayey soils lifted up the shallow ground water level up to 30cm or 100cm, which
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resulted in inducing the evaporation rate from the soil surface and in the salt accumulation. We concluded that the acceleration of evapo-transpiration rate by planting the salt patient grasses may induce the homeostatic function of soils.
2. Homeostatic function of soils on carbon cycles It is well known that the CO_2 gas emission from soils increases quickly when rain water infiltrate into soils. We found that this sudden increase of CO_2 emission is attributed to the sudden increase of microbiological activities with the increase of soil moisture. The priming effect of soils, which describes the excess emission of CO_2 compared with supplied organic matter into the soils, was observed experimentally and was discussed in detail.
3. Homeostatic function of soils on thermal cycles High temperatures of soils under forest fires, especially in tropical forest, damage the biological environment We investigated the homeostatic functions of soils under the forest fire where the soil moisture reduced the increase of soil temperature by absorbing the latent heat of water vaporization. Less
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