Japan Geoscience Union Meeting 2016

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS06] Biogeochemistry

Sun. May 22, 2016 10:45 AM - 12:15 PM A03 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Muneoki Yoh(Tokyo University of Agriculture and Technology), Hideaki Shibata(Field Science Center fot Northern Biosphere, Hokkaido University), Naohiko Ohkouchi(Japan Agency for Marine-Earth Science and Technology), Youhei Yamashita(Faculty of Environmental Earth Science, Hokkaido University), Chair:Tomoya Iwata(Faculty of Life and Environmental Sciences, University of Yamanashi), Urumu Tsunogai(Graduate School of Environmental Studies, Nagoya University), Yoshiyuki Inagaki(Forestry and Forest Products Research Institute), Kazumichi Fujii(Forestry and Forest Products Research Institute)

11:15 AM - 11:30 AM

[MIS06-09] Nitrogen isotope patterns of trees and soils in two different nitrogen deposition forests

*Ayumi Oda Tanaka1, Yoshiyuki Inagaki2, Xue-Yan Liu3, Midori Yano4, Keisuke Koba4, Keizo Hirai1 (1.Forestry and Forest Products Research Institute, 2.Shikoku Research Center, Forestry and Forest Products Research Institute, 3.Chinese academy of sciences, 4.Center of ecological research, Kyoto University)

Keywords:Nitrogen isotope ratio, Nitrogen deposition , Inorganic nitrogen

Anthropogenic nitrogen (N) deposition on forest site is concerning to modify plant species diversity and soil-to-plant N uptake. The N isotope ratio (δ15N) of soil and foliage reflects nitrogen cycle in the ecosystem and distinct plant N source. To better understand the effects of N deposition to soil N status and plant N uptake, we analyzed N content and δ15N of soils and foliage in two different N deposition forests (Mt. Tsukuba: 11.5 kg N ha-1 year-1, Katsura: 7.5 kg N ha-1 year-1) in Kanto region. We sampled soil from upper and lower position of the two forest site respectively, and measured extracted inorganic N content and isotope ratio. We also analyzed leaf N content (N%) and δ15N values of 30 woody species with different life forms (canopy and understory species). The soil nitrate concentration in Mt. Tsukuba was 25 fold higher than Katsura, and the δ15N value was constant through the site (-2.6 ± 0.1‰). While in Katsura, ammonium concentration in soil was high especially in upper slope, but in lower slope dominated nitrate. The foliage N% was high in Mt. Tsukuba than Katsura. The foliage δ15N value differed significantly among species in Katsura but in Mt. Tsukuba foliage δ15N value showed steady through species and the value corresponded with soil nitrate δ15N. From these results, N deposition may lead changing soil N status and alter plant N source and uptake.