1998 Fiscal Year Final Research Report Summary
Regulatory functions of soil-plant ecosystems to geochemical element cycling
| Project/Area Number |
08456038
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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 |
Plant nutrition/Soil science
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| Research Institution | Hokkaido University |
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Principal Investigator |
HATANO Ryusuke Fac.of Agr., Hokkaido Univ., Pro., 農学部, 教授 (40156344)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Yumiko Fac.of Agr., Experiment Forest, Hokkaido Univ., Inst., 農学部・附属苫小牧演習林, 教務職員 (60221397)
KURAMOCHI Kanta Fac.of Agr., Hokkaido Univ., Inst., 農学部, 助手 (00225252)
HARAGUCHI Akira Fac.of Sci., Niigata Univ., Asso.Pro., 理学部, 助教授 (50271630)
SATOH Fuyuki Fac.of Agr., Experiment Forest, Hokkaido Univ., Asso.Pro., 農学部・附属天塩演習林, 助教授 (20187230)
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| Project Period (FY) |
1996 – 1998
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| Keywords | element cycling / soil-plant ecosystem / acid-precipitation / carbon dioxide / nitrous oxide / methane / nitrate leaching / soil structure |
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| Research Abstract |
Soil-plant system develops element cycling in the system. Element cycling determines the quality of aquasphere and atmosphere by inter-diffusion of elements between pedosphere and atmosphere and outflow from pedosphere to aquasphere. This study was conducted to investigate the element cycling and to evaluate the effect of human activity on element discharge from the soil-plant system.
Results obtained from the investigation for base-cation cycling in forest-ecosystems showed those base cations in forest soils decreased, while base cations in plants increased. This suggests that atmospheric input is indispensable to sustain the soil-plant system. However, atmospheric supply of ammonium induces soil acidification due to nitrification. Generally, nitrogen supply improves plant growth, but bigger growth also requires other nutrients. Therefore. the induced soil acidification effect is due to the acceleration of base cation uptake by plant Consequently, soil acidification will reduce plant g
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rowth. Thus, plant-nutritional balance in atmospheric inputs is important from the viewpoint of the law of the minimum, In the same manner, excess fertilization induces nitrate leaching and emission of nitrous oxide, resulting in the degradation of the quality of aquasphere and atmosphere.
Land use change and waste control in urban area also influenced element cycling in regional scale. For example, dam-lake constructed to maintain water resources became a source of methane emission, indicating that a greater impact occurs more than just decreasing the area of forest soil, which absorbs methane from the atmosphere. Investigation of regional nitrogen cycling in Hokkaido indicated that amble land soil became eutrophic due to intensive agricultural management. Many human and animal wastes were not recycled and a substantial amount of nitrogen from the wastes was discharged to the river. Concerning this problem, a forest soil limited by the law of the minimum and an eutrophic arable land do not have any capacities to regulate such kind of skewed regional nutrient cycling.
Soil-plant system regulates geochemical element cycling by means of biogeochemical element cycling including plant uptake and organic matter decomposition. However, soil-plant system is also influenced by atmospheric inputs and is easily changed by human activity. Consequently, the regulatory function of soil-plant system and the system itself may be fragile to maintain environmental quality. We should conserve the function and the system. Therefore, it is required to study the interrelationship between nutrients in biogeochemical cycling. Less
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Research Products
(12 results)
