Effects of N Fertilizer Application Rates on N2O Emissions from a Vegetable Field in Wuhan, China - A Lysimeter Study

摘要

Nitrous oxide (N2O) emissions from a typical vegetable cropping system in Wuhan, central China were measured from April 2007 to September 2008 on undisturbed soil monolith lysimeters using the closed chamber method. N2O emissions showed an immediate and pronounced increase to additions of N fertilizer. Peak N2O emissions were 42.5, 68.8, 548, 386 and 868 μg N m-2 h-1 in the N0, N1, N2, N3 and N4 treatments, respectively. 65.2-77.0% of the total N2O emissions were produced between April and September. Total N2O emissions ranged from 1.4 to 25.6 kg N ha-1 in the five treatments and the emission factor of the N1, N3 and N4 treatment varied from 0.30% to 2.05%, and that for N2 was 1.84-3.59%. There was a significant exponential relationship between the N application rate and total N2O emissions, and the soil temperature was highly correlated to the N2O emissions. The results also indicate that emissions from vegetable fields are a potential source of national N2O flux in China.