[M-IS21_28PM1] 生物地球化学

[MIS21-18] 窒素肥料および窒素降下物による全球陸域窒素循環の改変

*仁科 一哉¹、伊藤 昭彦¹、花崎 直太¹、眞崎 良光¹ (1.国立環境研究所)

キーワード：窒素肥料, 窒素降下物, 亜酸化窒素, 土地利用変化, N溶脱

Human activities have considerably disturbed terrestrial nitrogen cycling especially after the industrial revolution. Because Harbor-Bosch techniques and fossil fuel combustions have been large sources of reactive nitrogen to the terrestrial ecosystems. The recent N loading derived from these sources on terrestrial ecosystems was estimated 2 times higher than biogenic N fixation in terrestrial ecosystems (Gruber et al., 2009). In this study, we evaluated N fertilizer and N deposition on global terrestrial N cycling using ecosystem model 'VISIT' and global datasets. For the cropland, we made spatial temporal explicit N fertilizer input data (as NH4+ and NO3- respectively) made by FAO statistics, historical land-use dataset and global crop calendar in SAGE dataset. For N deposition, we used global grid data from Galloway et al. (2004) with simple interpolation in time-series. From the simulation results, we evaluated historical N cycling changes by land-use changes and N depositions in N cycling (e.g., N leaching, N2O, NO) at global scale.