Plant species of cropping systems may affect nitrous oxide (N2O) emissions.A field experiment was conducted to investigate dynamics of N2O emissions from rice-wheat fields from December 2006 to June 2007 and the relationships of soil and plant parameters with N2O emissions.The results indicated that N2O emissions from different wheat varieties ranged from 12 to 291 μg N2O-N m-2 h-1 and seasonal N2O emissions ranged from 312 to 385 mg N2O-N m-2.In the rice season,it was from 11 to 154 μg N2O-N m-2 h-1 with seasonal N2O emission of 190-216 mg N2O-N m-2.The seasonal integrated flux of N2O differed significantly among wheat and rice varieties.The wheat variety HUW 234 and rice variety Joymoti showed higher seasonal N2O emissions.In the wheat season,N2O emissions correlated with soil organic carbon (SOC),soil NO-3-N,soil temperature,shoot dry weight,and root dry weight.Among the variables assessed,soil temperature followed by SOC and soil NO-3-N were considered as the important variables influencing N2O emission.N2O emission in the rice season was significantly correlated with SOC,soil NO-3-N,soil temperature,leaf area,shoot dry weight,and root dry weight.The main driving forces influencing N2O emission in the rice season were soil NO-3-N,leaf area,and SOC.
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