Japan Geoscience Union Meeting 2016

Presentation information


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

[M-IS06] Biogeochemistry

Sun. May 22, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

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)

5:15 PM - 6:30 PM

[MIS06-P04] Mean residence time of leaf nitrogen and leaf longevity of hinoki cypress (Chamaecyparis obtusa) under nutrient-poor soil

*Asami Nakanishi1, Yoshiyuki Inagaki2 (1.Field Science Education and Research Center, Kyoto University, 2.Shikoku Research Center, Forestry and Forest Products Research Institute)

Keywords:mean residence time of leaf nitrogen, leaf longevity, leaf production, hinoki cypress, organic horizon

Mean nitrogen residence time of plants is decided by nitrogen resorption and leaf longevity. However, there is little knowledge about intra-specific variation in leaf longevity and mean nitrogen residence time along a soil nitrogen gradient. We evaluated the effects of nitrogen resorption and leaf longevity on mean residence time of leaf nitrogen (leaf-N MRT) of hinoki cypress under different soil nutrient status.
Mean residence time of nitrogen in organic horizon (A0N-MRT) was used as the index of soil nutrient status. A0N-MRTs ranged 5.4 to 38.3 years that were longer than those in other stands of hinoki cypress. Leaf longevity and leaf-N MRT increased as A0N-MRT increased. Leaf production and leaf-fall nitrogen mass decreased with increasing A0N-MRT. There were no significant relationships between A0N-MRT and nitrogen resorption, leaf biomass, leaf nitrogen mass, nitrogen concentrations of fresh-leaf and leaf-fall. Nitrogen resorption was higher than that in other stands of hinoki cypress. It was suggested that nitrogen resorption did not significantly correlated with A0N-MRT because of high resorption rate in all plots. These findings indicated that hinoki cypress under nutrient-poor soil to maximize mean residence time of leaf nitrogen increased nitrogen resorption before leaf-fall first, and additionally, altered leaf longevity by changing leaf production along a soil nitrogen gradient.