| Project/Area Number |
16380155
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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 | Yamagata University |
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Principal Investigator |
IIDA Toshiaki Yamagata University, Faculty of Agriculture, Associate professor, 農学部, 助教授 (30193139)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | nitrous oxide / paddy field / intermittent irrigation / mid-summer drainage / water management / greenhouse gas / methane / 間断灌漑 / 地球温暖化ガス / ガス放出 / 農業土木 |
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| Research Abstract |
To characterize methane emission from paddy soil with intermittent irrigation at different intervals, a laboratory experiment was conducted. After approximately 1 month continual flooding on non-disturbed soil samples, intermittent irrigation with the cycle of 4 day flooding and 4 day drying and the cycle of 2 day flooding and 2 day drying were conducted in parallel. The methane emission decreased during the flooding and increased during the drying. It was thought that accumulated methane during the flooding tends to emit during the drying through soil pores opened to the atmosphere. The total methane emission was higher in the 4 day flooding 4 day drying system because of the enhanced anaerobic state.
Methane and nitrous oxide emission were measured at 2 practical paddy fields for 6 months from the transplanting until snow covers the fields at the frequency about 1-2 times a week. During intermittent irrigation, peaks of gas emissions occurred after irrigation and drainage actions with several days delays. After harvest, the nitrous oxide emission was low, while a sudden high methane emission was observed.
Rice plants were grown in pots with three treatment plots, i.e. the early intermittent irrigation plot (EII) in which intermittent irrigation began just after transplantation, the early mid-summer drainage plot (EMD) in which mid-summer drainage began about 1 week earlier than the conventional method, and the conventional plot (CON). The methane emission was half at EII and EMD compared to that at CON, probably owing to repetition of anaerobic and aerobic conditions and earlier mitigation of anaerobic condition. The nitrous oxide emission fluctuated at EII and it enhanced after the mid-summer drainage at EMD. Another laboratory experiment with intermittent irrigation showed the tendency that both methane and nitrous oxide emission increased during flooding and decreased during drying.
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