氮肥施用量是影响农业生产过程中温室气体排放的重要因素。为探究合适的施氮量以保障水稻产量、提高氮肥利用率、减少温室气体排放,本研究在试验田设置6个施氮水平(0、75、150、225、300、375 kg N·hm~(-2)),收集种植过程中主要农业温室气体甲烷(CH_4)和氧化亚氮(N_2O),计算排放总量、全球变暖潜能(GWP)及其与施氮水平和环境条件之间的相关性。结果表明,225 kg N·hm~(-2)的施氮水平下,水稻在保持较高产量的同时,相较于其他处理单位粮食产量下排放更少的GWP,每千克水稻产量排放 GWP值为0. 31 kg CO_2-eq(二氧化碳当量); N_2O排放总量随氮肥施用量增加而增加,CH_4排放总量随施氮量增加而减少,CH_4和N_2O排放高峰期分别集中在种植前期和中后期。本研究结果为杭州地区水稻种植合理施肥量提供了理论依据。
英文摘要:
Nitrogen fertilization rate was believed to produce great influence on greenhouse gas (GHG) emission in paddy field. Thus,it is important and necessary for paddy field management to provide a suitable nitrogen fertilization rate to ensure rice yield and reduce GHG emission. In this study,six levels (0,75,150,225,300 and 375 kg N·hm~(-2)) of fertilizer application rates were designed to test the GHG emission flux by measuring methane (CH_4),nitrous oxide (N_2O) emission flux and accumulation of global warming potential (GWP),meanwhile the correlation between GHG emission and environmental element was also analyzed. Results showed that 225 kg N·hm~(-2) fertilizer rate presented a relatively high rice yield and a low GWP emission with 0. 31 kg CO_2-equivalent per kilogram rice yield. More nitrogen fertilization application resulted in more N_2O emission and less CH_4 emission. CH_4 and N_2O emission peaks appeared at vegetative and ripening phase of rice growth period. This study provides a scientific basis for suitable nitrogen fertilization rate management at paddy field in Hangzhou.