| Project/Area Number |
09480113
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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 |
Environmental dynamic analysis
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| Research Institution | University of Tsukuba |
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Principal Investigator |
TASE Norio Univ. Tsukuba Inst. Geoscience Professor, 地球科学系, 教授 (40133011)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMADA Jun Univ. Kumamoto Dept. Science Professor, 理学部, 教授 (80206169)
TAMURA Kenji Univ. Tsukuba Inst. Applied Biochem. Assoc. Professor, 応用生物化学系, 助教授 (70211373)
TABAYASHI Akira Univ. Tsukuba Inst. Geoscience Professor, 地球科学系, 教授 (70092525)
SUGITA Fumi Chiba Univ. Commerce Assoc. Professor, 商経学部, 助教授 (40275962)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | land use / Kanto loam / physical and chemical properties of soil / soil water / groundwater / nitrate ion / sulfate ion / tea plantation |
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| Research Abstract |
The purposes of this study are to clarity memory effects of soil layers by agricultural activities on the surface for a long time, interactions of soil layers and subsurface water and chemical evolution of groundwater. As a study area, the Kaneko terrace was selected where the soil layer was thick, the ground water level was deep, and the land use, especially the agricultural utilization was long. The nitrate concentration of the groundwater over the Kaneko terrace exceeds 200mg/L, and the effect of the agricultural activity in long time was recognized. Much nitrate and sulfate ions were accumulated in the loam later in tea plantation, and became 10 and two times of the non-fertilized land, respectively. Though the nitrate ion abundantly accumulated all through the layer, the sulfate ion was to surface layer of 4 m. The sulfate ion retained in the soil long after stop of the fertilization. Though the depth profiles of the stable isotope ratios of nitrogen and carbon showed some features which were attributed to the effect of agricultural activity, the relation with the stratigraphy of the loam layer was also considered. From the depth profile of tritium concentration, infiltration rate of soil water was estimated for 1.2m/year. In the depth profiles of the stable isotope ratios of hydrogen and oxygen, there was the periodic fluctuation to the 4m depth, which would retain the recharge patterns and shows the possibility of the estimation of infiltration rate and recharge amount. It was shown that the depth profile of observed nitrate ion was simulated well by the advection-diffusion model with nitrification by the zeroth-order reaction and denitrification by first-order reaction.
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