1994 Fiscal Year Final Research Report Summary
Seepage-water Pollution and its Prevention in Shirasu Area
| Project/Area Number |
05660282
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | Kagoshima University |
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Principal Investigator |
MIWA Kojchi Kagoshima University, Agriculture, Professor, 農学部, 教授 (40032099)
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| Co-Investigator(Kenkyū-buntansha) |
WAKAMATSU Chiaki Kagoshima University, Agriculture, Lecture, 農学部, 講師 (70041647)
CHO Katushi Kagoshima University, Agriculture, Asso.Professor, 農学部, 助教授 (20038235)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Shirasu upland / Control of nitrate / Seepage-water pollution / Nitrate content / Rice straw |
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| Research Abstract |
For the prevention of seepage-water pollution by nitrate, the purpose of this project is to control its outflow from upland in Shirasu area, south of Kyushu.The results obtained from column tests are summerized as follows ;
1. By putting the rice straw of 10 g/84cm^2 under the plow layr, the outflow of nitrate was able to restrain during about 80days, If the soil was maintained under the condition of reduction. From column tests, the nitrate of 64kg/ha/y was removed.
2. The nitrate content of water in each 10 stages of column was high above the rice straw layr. On the other hand, its content was remarkably reduced under that layr. Therefore, the rice straw controlled temporarily the outflow of nitrate.
3. For the reduction of nitrate content, the rice straws putting under the plow layr was more effective than thoase mixing it.
However, during typhoon or heavy rain seasons in Shirasu area, the nitrate is easily flowed out. For this reason, it is important for the prevention of groundwater pollution to use some procedures, such as water management, soil condition and cultivation program.
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