2005 Fiscal Year Final Research Report Summary
Effect of nitrogen deposition on fluxes of green house gases in a forest ecosystem
| Project/Area Number |
15380045
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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 Hokkaido University, Field Science Center for Northern Biosphere, Professor, 北方生物圏フィールド科学センター, 教授 (40156344)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAHARA Osamu Hokkaido University, Graduate School of Agriculture, Associate professor, 大学院・農学研究科, 助教授 (10253519)
HATA Hiroshi Hokkaido University, Field Science Center for Northern Biosphere, Associate Professor, 北方生物圏フィールド科学センター, 助教授 (30250492)
SHIBUYA Masato Hokkaido University, Graduate School of Agriculture, Associate Professor, 大学院・農学研究科, 助教授 (10226194)
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| Project Period (FY) |
2003 – 2005
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| Keywords | nitrogen deposition / global warming gas / methane / ammonium / nitrate / forest soil / global warming / nitrogen saturation |
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| Research Abstract |
Nitrogen deposition has been known to affect emission and absorption of green house gases in forest ecosystems. Nitrogen deposition enhances nitrous oxide emission from forest soils and inhibits methane emission into forest soils. Nitrogen deposition might enhance or diminish forest growth and CO_2 sequestration. Most researches, however, focus on nitrogen-saturated forests receiving high deposition of nitrogen (DIN > 10 kgN ha^<-1> y^<-1>), and we need more information on the effect of nitrogen deposition on green house gases fluxes in forests receiving low nitrogen deposition (DIN < 10 kgN ha^<-1> y^<-1>). IPCC proposed the concept of 'Global Warming Potential' (GWP) as a comprehensive measure of effect of ecosystem biogeochemical processes on global warming. Previous studies mainly focused on one of these green house gases, e.g., carbon dioxide, nitrous oxide and methane. Very few studies reported total effect of these gases or GWP of forest ecosystems. The purpose of this study is
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to reveal the effect of very low nitrogen deposition on GWP in a larch forest. We studied at five sites in larch forest in Mt. Shirahata, Sapporo city, northern Japan. N_2O emission and CH_4 absorption at the surface of soil/snowpack were measured with closed chamber method. CO_2 sequestration was estimated with measurement of tree heights and diameters at breath height, allometric equation, and microbial respiration measured by incubation of moist soils in laboratory.
Nitrogen deposition during no-snow season ranged 0.8 〜 1.8 kgN ha^<-1> y^<-1>. Annual CH_4 absorption ranged 5 〜 7 kgC ha^<-1> y^<-1> and showed no correlation with nitrogen deposition. But comparison of our result with literature data suggested that high CH_4 absorption in this study site was caused by very low nitrogen deposition that is known to inhibit CH_4 absorption. Nitrous oxide emission in this study was classified as background type emission because N_2O emission showed no correlation with soil temperature and soil moisture. Background type N_2O emission has been believed not to affected by nitrogen deposition. Annual N_2O emission ranged 0.02 〜 0.09 kgN ha^<-1> y^<-1>. Accumulated N_2O emission during no-snow season showed positive correlation to nitrogen deposition during now-snow season. Comparison of our results with literature data on background type N_2O emission suggested that even background type N_2O emission is affected by nitrogen deposition. Net ecosystem productivity (NEP) ranged 0.2 〜 2.1 tC ha^<-1> y^<-1>. NEP showed positive correlation to nitrogen deposition during no-snow season. Calculation of GWP revealed that CO_2 sequestration by forest vegetation was largest component in GWP in this study site ; contribution of N_2O emission and CH_4 absorption to GWP was negligible. In summary, nitrogen deposition has a negative effect on global warming and tree growth enhancement by nitrogen deposition has much larger role than enhanced N_2O emission and reduced CH_4 absorption by nitrogen deposition. Less
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[Journal Article] Effect of nitrogen deposition on stream water nitrate and nitrous oxide emission in larch forest in the northern Japan2005
Author(s)
Nakahara, O., Yamagami, T., Koide, T., Sakai, T., Morishita K., Hatano, R.
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Journal Title
3rd International Nitrogen Conference-Contributed Papers
Pages: 912
Description
「研究成果報告書概要(欧文)」より
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[Book] 3rd International Nitrogen Conference - Contributed Papers2005
Author(s)
Nakahara, O., Yamagami, T., Koide, T., Sakai, T., MorishitaK., Hatano, R.
Total Pages
912
Publisher
Science Press, USA
Description
「研究成果報告書概要(和文)」より
