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| Effects of reclamation on the N2O reduction potential of paddy soils in coastal wetlands |
| Received:May 13, 2020 |
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| KeyWord:reclamation;coastal paddy field;nosZ gene;N2O reduction potential |
| Author Name | Affiliation | E-mail | | WANG Fang-yuan | Collaborative Innovation Center for Forecast and Evaluation of Meteorological Disasters/Jiangsu Provincial Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | ZHANG Yao-hong | Collaborative Innovation Center for Forecast and Evaluation of Meteorological Disasters/Jiangsu Provincial Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | yhzhang@nuist.edu.cn | | RAO Xu-dong | Collaborative Innovation Center for Forecast and Evaluation of Meteorological Disasters/Jiangsu Provincial Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | XIE Qing | Collaborative Innovation Center for Forecast and Evaluation of Meteorological Disasters/Jiangsu Provincial Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | JIA Zhong-jun | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | |
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| Abstract: |
| The nitrous oxide (N2O)reduction potential of paddy fields is of great significance for mitigating atmospheric greenhouse gas emissions. However, N2O reduction rates of tillage layer soil and the underlying microbial mechanisms remain unclear after the reclamation of coastal natural wetland as paddy fields. In this study, the Chongming Dongtan Natural Wetland in the Yangtze River estuary was selected as the control (WK0), and N2O reduction potential and related microbial quantity characteristics were investigated in paddy field soils with different reclamation years (19, 27, 51 a, and 86 a). The results showed that total organic carbon (TOC)soil content increased significantly as the reclamation period increased, whereas pH, EC value, and SO 2 4-concentration gradually decreased. The N2O reduction rates increased significantly as the reclamation period increased, and the N2O reduction rate in the paddy field with an 86 a reclamation period was 25.5 μg N2O·g-1·d-1, which was 58.4% higher than that of natural wetlands (WK0). The copy numbers of nosZ Ⅰ and nosZ Ⅱ genes increased as the reclamation period increased, and the copy numbers of the paddy field with an 86 a reclamation period were 1.72×108 copies·g-1 and 4.36×108 copies·g-1, which were one order of magnitude higher than those of natural wetlands. The correlation analysis showed that the N2O reduction rate was positively correlated with the abundance of nosZ Ⅰ gene, whereas the increase in the copy number of the nosZ Ⅱ gene was much higher than that of the nosZ Ⅰ gene as the reclamation period increased. The N2O reduction rate and the copy number of nosZ Ⅰ and nosZ Ⅱ genes was negatively correlated with pH, EC, and SO42- concentration in the soil. Therefore, the reclamation of coastal wetlands into paddy fields promote the N2O reduction potential of topsoil; the significant increase in the number of nosZ Ⅰ genes is one of the primary factors controlling the N2O reduction rate increase. |
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