施氮和玉米生长对土壤氧化亚氮排放的影响

运用土壤盆栽试验、静态箱法采样和气相色谱分析技术研究了种植玉米土壤和裸土在两种土壤施氮水平 (低氮:150 mg·kg^-1土,和高氮:300 mg·kg^-1土) 下对土壤排放N₂O的影响.结果表明，在种植玉米的土壤中,N2O排放率的峰值出现在苗期,且氮肥施用量的影响显著,土壤N₂O排放率与温度没有显著的相关性.在裸土中,土壤N₂O排放率的峰值出现在试验后期,土壤N₂O排放率与温度呈极显著指数相关.土壤施氮量增加,土壤N₂O排放总量增加,裸土N₂O增加尤其显著,种植玉米比裸土减少87%～92%的N₂O排放量.这一结果表明种植作物与否,不仅改变了土壤N₂O排放的季节变化和排放量,而且改变了温度与土壤N₂O排放之间的关系.

Effects of N application and maize growth on N2O emission from soil

With pot experiment and using static chamber-GC technique, this paper studied the effects of N application (150 and 300 mg x kg(-1) soil) and maize growth on N2O emission from soil. In maize-planted soil, the N2O emission rate increased with increasing N application rate, its peak appeared at seedling stage, and there was no significant correlation between N2O emission and air temperature. Contrarily, in bare soil, the peak of N2O emission rate occurred at the anaphase of the experiment, and there was a significant exponential correlation between N2O emission and air temperature. The total amount of N2O emission increased remarkably with increasing N application rate in both planted and bare soils. In comparing with bare soil, maize-planting reduced N2O emission by 92% and 87%, respectively at high and low N application rates, which suggested that maize-planting not only affected the seasonal variation and magnitude of N2O emission from soil, but also altered the relationship between air temperature and soil N2O emission.