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

Using the pot experiment and closed static chamber-gas chromatography (GC) technique, this paper studied the effects of nitrogen application (150 and 300 mg/kg 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 the seedling stage, and there was no significant correlation between N₂O emission rate and air temperature. Contrarily, in exposed soil, the peak of N₂O emission rate occurred at the later stages of the experiment, and there was a significant exponential correlation between soil N₂O emission rate and air temperature, in which Q ₁₀ (the value of soil N₂O emission rate responding to temperature) was 4.4 and 3.2 in high and low N applications. The total amount of N₂O emission increased remarkably with increased N application rate in both planted and un-planted soils. N₂O emission inventory from exposed and maize-planted soils in high N application was 2.5 and 1.6 times as high as that in low N application, respectively. In the same N application rate, N₂O emission inventory in high and low N application from exposed soil was 12 and 7.5 times as high as that from maize-planted soil, respectively. As compared with exposed soil, maize growth reduced N₂O emission by 92% and 87%, respectively, at high and low N application rates. In summary, maize growth and nitrogen application 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. __________ Translated from Chinese Journal of Applied Ecology, 2005, 16(1): 100–104 译自: 应用生态学报]