[Contribution of different processes in wetland soil N2O production in different restoration phases of the Yellow River estuary, China].

By using the method of time-space mutual substitution,the contribution of different processes in wetland soil N2 O production was studied in the un-restoration wetland(R0),restoration wetland since 2007(R2007) and restoration wetland since 2002(R2002) of the Yellow River estuary to evaluate the effectiveness of the restoration projects. Results showed wetland soil total N2 O production had a significant difference in different restoration phases,but the N2 O release was the main source. The N2 O production in restoration wetland was higher than that in un-restoration wetland. The N2 O production was mainly due to the nitrification and nitrifier denitrification processes,while the denitrification process had great weakening effects on N2 O production,which was closely related to the physical and chemical properties of wetland soils in different restoration phases. The non-biological processes made greater contributions to N2 O production and these were mainly due to that iron was reductive,while the Yellow River estuary was an area of highly active iron. Although N2 O production in wetland soils was the results of biological processes combined with non-biological processes in different restoration phases,non-biological processes had larger influences and should be paid a special attention. There were different influences on wetland soil processes generating N2 O between temperature and water content,indicating responses of soil microbial activities to temperature and water content were different. In addition,the N2 O production contents ranged from 0. 37 ± 0. 08nmol·(kg·h)- 1to 9. 75 ± 7. 64 nmol·(kg·h)- 1in marshes of the Yellow River estuary,which was slightly higher than those in the S.alterniflora wetland soils of the Min River estuary,but significantly lower than those in the C. malaccensis wetland soils of the Min River estuary,the grassland soils and the aerobic forest soils. We found that the long-term implements of ecological restoration projectin the Yellow River estuary obviously promoted N2 O production,so we should consider two factors of landscape restoration and weakening greenhouse gases in the next wetland restoration project.