|| 要旨トップ | 目次 |||日本生態学会第63回全国大会 (2016年3月、仙台) 講演要旨
一般講演（口頭発表） E1-07 (Oral presentation)
Previous studies reported that N addition on P-limited ecosystems emitted more N2O than on N-limited ecosystems or NP-limited ecosystems, because P-limited ecosystems can hold a lower amount of the added N into microbial N pool. To test if this phenomenon occurs in other areas, we examined the effects of N and P additions on N2O emissions in two lowland dipterocarp forests with different strength of P-limitations on Mt. Kinabalu, Borneo. Root excluded areas were also prepared in each sub-plot to estimate root N uptakes. In contrast with previous reports, the same amount of N addition caused higher N2O emissions in less P-limited forest. Microbial N pools were not affected by N addition in both forests. These results were probably because N requirement by trees was higher in more severely P-limited forest. Root N uptakes were higher in more severely P-limited forest, and higher amount of N remained in soil in less P-limited forest. In the ecosystems on Mt. Kinabalu, P-limitation would drive N-limitation through constrained free-living N2 fixation, lower N turnover, and higher N consumption for producing phosphatase, resulting in more N-starved condition.