|| 要旨トップ | 目次 |||日本生態学会第65回全国大会 (2018年3月、札幌) 講演要旨
一般講演（ポスター発表） P2-313 （Poster presentation）
The increasing global atmospheric nitrogen (N) deposition has an important impact on soil respiration. Due to different sources of different components of soil respiration, there are different mechanisms for the responses to N additions. To investigate the effect of N addition on total soil respiration (RST), rhizospheric respiration (RSR) and heterotrophic respiration (RSH), one N addition experiment was conducted in a subtropical evergreen broad-leaved forest. Three N treatments (+0, +50, +150 kg N ha−1 yr−1) were added monthly to soil surface since April 2013. Soil respiration was measured monthly from May 2015 to April 2016. The results showed that the annual mean rate of RST was 1.92 ± 0.18 μmol CO2 m−2 s−1 (7.3 ± 0.7 t C ha−1 yr−1), RSH and RSR contributed (75 ± 1) % and (25 ± 1) % to RST, respectively. Nitrogen addition significantly reduced RST by reducing RSH and RSR. Nitrogen addition decreased the RSR by reducing belowground carbon (C) allocation. RSH decreased mainly due to the reduced microbes and soil organic matter (SOM) decomposition in root-free soil after N addition.