The N2O concentration and the relationships with ammonia-oxidizing bacteria and denitrifiers abundance in root zone and row of summer maize

The N2O concentration in the root dense zone and the row of summer maize and the relationships with bacteria abundance (ammonia-oxidizing bacteria (AOB) and denitrifiers) were measured using silicon tube method and microbial molecular technology in a typical dry land agricultural soil in the North China Plain. The results showed that the great amount of N2O was produced after fertilization and irrigation measures and above 15 mm precipitation. N2O concentration in the row is higher than in root dense zone of summer maize slightly, but not reached significant difference. The correlation analysis showed that the significant positive relationship were observed between N2O concentration and water-filled porespace (WFPS) and the content of NO3--N, the determination coefficient reached 0.79 and 0.51, respectively; and the significant positive relationship were observed between N2O concentration and the copy numbers of amoA and nirS also, the determination coefficient reached 0.55 and 0.62, respectively, it indicated that environment factors (WFPS and the content of NO3--N ) and the changes of AOB and denitrifiers abundance influenced N2O production significantly. In conclusion, in our experiment conditions, the consume of N and water due to maize root growth and the changes of AOB and denitrifiers in the root dense zone not caused N2O production significant difference between the root dense zone and row of summer maize. Thus, when we install the closed chamber in the field, whether included plant root or not have no significant influence to the results of N2O emission.