1992 Fiscal Year Final Research Report Summary
Methane Emission in Paddy Fields and its Control
| Project/Area Number |
02453121
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
土壌・肥料
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| Research Institution | Tokyo University of Agriculture |
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Principal Investigator |
TAKAI Yasuo Tokyo Univ. of Agriculture, Faculty of Agriculture, Professor, 農学部, 教授 (40011796)
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| Co-Investigator(Kenkyū-buntansha) |
WADA Eitaro Kyoto University, Center for Ecological Research, Professor, 生態学研究センター, 教授 (40013578)
YOSHIBA Masaaki Tokyo Univ. of Agriculture, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (20078190)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Paddy Fields / Rice Cultivation / Methane Emission / Organic Materials / Carbon Isotopic Ratio |
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| Research Abstract |
This study aims to elucidate 1)how rice growth affects methane emission in paddy fields, 2)how the application of rice straw and cow dung manure affects paddy methane emission and 3)methane production mechanism in paddy fields using carbon isotopic analysis. The results are summarized as follows.
1) The volume of methane emission going through rice stem was one to four times as that of methane emission from paddy soil surface. Total volume of methane emission was twice at the rice straw applied plot and 1.0 to 1.4 times at the cow dung manure plot as that at the control plot. The intermittent drainage was no effective to suppress paddy methane emission, although the drainage rose soil Eh to some extent.
2)delta^<13>C of bubble methane was very useful parameter for assessing the production mechanism of methane in submerged soils. The end member of delta^<13>C(CH_4) from acetic acid fermentation was -37+3*, while -72* from CO_2/H_2 process. Using these facts, two source model can be used to evaluate relative source strength of each process for soil methane production. Significance difference in delta^<13>C value of soil methane was found between the rice straw plot and the cow dung manure plot. The delta^<13>C value of the latter was higher than -30%。, strongly suggesting the occurrence of methane oxidation within the flooded soil.
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