Nitrous Oxide Emissions from Fields with Different Wheat and Rice Varieties

摘要

Plant species of cropping systems may affect nitrous oxide(N 2 O) emissions.A field experiment was conducted to investigate dynamics of N 2 O emissions from rice-wheat fields from December 2006 to June 2007 and the relationships of soil and plant parameters with N 2 O emissions.The results indicated that N 2 O emissions from different wheat varieties ranged from 12 to 291 μg N 2 O-N m 2 h 1 and seasonal N 2 O emissions ranged from 312 to 385 mg N 2 O-N m 2.In the rice season,it was from 11 to 154 μg N 2 O-N m 2 h 1 with seasonal N 2 O emission of 190-216 mg N 2 O-N m 2.The seasonal integrated flux of N 2 O differed significantly among wheat and rice varieties.The wheat variety HUW 234 and rice variety Joymoti showed higher seasonal N 2 O emissions.In the wheat season,N 2 O 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 N 2 O emission.N 2 O 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 N 2 O emission in the rice season were soil NO 3-N,leaf area,and SOC.