N2O emissions from agricultural soils in the North China Plain:the effect of chemical nitrogen ferti

An enclosed chamber technique was used to measure N2O emissions from intensively agricultural soils of the North China Plain during the periods of 1995-1996 and 1997-1998, to reflect distinct components of winter wheat and summer maize growing seasons. The results showed that the continuous application of fertilizer in agricultural soils increased N2O emissions by a factor of 24. 1-28.1, the calculated annual chemical N fertilizer-transformed N2O-N emissions was 0.67%. Our results indicated that the application of organic manure also had a significant influence on soil N2O emissions, which combined with the use of chemical N increased about 20% in a year. It was calculated that there were about 0.11% N of organic manure transformed as N2O-N. Annual mean N2O emission from our study area of fertilized soils was estimated to be 57.1 μgN2O/(m2 ＠ h). A weak correlation was also found between. N2O emissions and soil available nitrogen content NH+4 .