| Project/Area Number | 02454068 |
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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 |
林学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
IWATSUBO Goro Fac. of Agriculture, Professor, 農学部, 教授 (00026395)
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| Co-Investigator(Kenkyū-buntansha) |
TOKUCHI Naoko Fac. of Agric., Instructor., 農学部, 助手 (60237071)
KAWAGUCHI Hideyuki Fac. of Agric., Instructor, 農学部, 助手 (40202030)
TAKEDA Hiroshi Fac. of Agriculture, Associate Prof., 農学部, 助教授 (60109048)
FUKUSHIMA Yoshihiro Fac. of Agric., Associate Prof., 農学部, 助教授 (00026402)
OOHATA Seiichi Fac. of Agric., Associate Prof., 農学部, 助教授 (50026639)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed(Fiscal Year 1992)
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| Budget Amount *help |
¥5,800,000 (Direct Cost : ¥5,800,000)
Fiscal Year 1992 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1991 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 1990 : ¥2,600,000 (Direct Cost : ¥2,600,000)
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| Keywords | Forest run-off water / Purification ability / Soil water / Upper and lower slope / Ion exchange resin / Nitrification / Denitrification / 不連続的分布 / 相乗的相互作用 / 浄化機能 / 斜面上部 / 斜面下部 / 硝酸態窒素 / アンモニア態窒素 / 森林 / 集水域 / 降水 / 流出水 / 水質 / 洪水 / 崩壊地 / 浄化作用 |
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| Research Abstract |
1990: Runoff water-chemicals were studied in seven man-made Sugi forest stands of variable ages and four natural and deciduous broad-leaved forest stands at the Kyoto University Forests. Studies were conducted every 2 weeks and compared with that precipitation. NO_3-N concentration in runoff water decreased considerably compared to precipitation. About the same concentration of NH_4-N, org-N, and total-P were detected in runoff water and precipitation. As the amount of runoff water decreased to 2/3 of the precipitation, we can say that the forest purifies eutrophication substances such as nitrogen and phosphorus.
1991: As no apparent difference was detected among the runoff water-chemicals of the variable forest stands in this University Forest, our investigation efforts were concentrated into the details of forest mechanisms in regulating runoff water chemicals. Ion exchange resins were buried along the forest slope and the amount of water-chemicals which infiltrate through the soil was measured. At lower slope, the amount of chemicals detected was several times that of upper slope. Through the experiment of soil water-chemicals measurement using lysimeter, an increase of nitrate along the slope was detected from upper to lower slope. The increase of nitrate also brought about an increase of calcium and magnesium.
1992: At soil depth of 50cm in lower slope, a high concentration of nitrate was detected. To follow the fate of this nitrate nitrogen, the natural isotope abundance ratio of nitrogen was measured and denitrification in the water saturated layer was confirmed. Along a continuous slope, nitrification and base saturation in the soil changed punctually with the positive feedback interaction between biological and environmental factors.
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