Evaluation of tropical fast wood plantation as a new emission source of nitrous oxide and development of mitigation options

本文研究了印尼苏门答腊岛相思人工林土壤表面氧化亚氮（N_2O）通量，并探讨了减少N_2O的缓解方案。所得结果如下：(1) mangium人工林土壤N2O排放量显著高于同地区次生林；(2)马尾松人工林N_2O排放具有明显的季节波动特征，丰水季高，旱季低。(3) N2O通量最高可达正常年份的4 ~ 5倍，特别是在树木采伐后立即增加。(4)同一林分N2O通量在干湿季节均表现出明显的空间异质性，其成因也各不相同。(5)土壤炭施用具有降低土壤N2O排放的潜力，施磷也通过促进根系对氮的吸收抑制了土壤N2O的排放。

We investigated the soil surface nitrous oxide (N_2O) flux in the Acacia mangium plantations, and some mitigation options to reduce it on Sumatra, Indonesia. The results obtained were as follows. (1) The soil of A. mangium plantation was emitting significantly larger amounts of N2O in comparison with the secondary forests in the same area. (2) N_2O emission from A. mangium plantation showed clear seasonal fluctuation, high in wet season and low in dry season. (3) N2O flux reached up to 4 to 5 times higher particularly immediately after tree harvest than in usual year. (4) N2O flux showed a pronounced spatial heterogeneity even in the same stand both in a wet and dry seasons, and their causes were different from each other. (5) Application of charcoal to soils have potentials to reduce N2O emission from the soil, and phosphorous application is also suppressed the emission through promoted nitrogen absorption by tree roots.