Nitrous Oxide Emissions from Fields with Different Wheat and Rice Varieties

Abstract

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