| 汪方圆,张耀鸿,饶旭东,谢晴,贾仲君.围垦对滨海稻田土壤N2O还原潜力的影响[J].农业环境科学学报,2020,39(11):2668-2674. |
| 围垦对滨海稻田土壤N2O还原潜力的影响 |
| Effects of reclamation on the N2O reduction potential of paddy soils in coastal wetlands |
| 投稿时间：2020-05-13 |
| DOI：10.11654/jaes.2020-0533 |
| 中文关键词: 围垦 滨海稻田 nosZ基因 N2O还原 |
| 英文关键词: reclamation coastal paddy field nosZ gene N2O reduction potential |
| 基金项目:国家自然科学基金项目（41671247，41103039）；江苏省自然科学基金项目（BK20171455）；国家留学基金项目（201908320185） |
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| 中文摘要: |
| 稻田湿地生态系统的N2O还原消耗潜力对缓解大气温室气体效应具有重要意义，而滨海自然湿地围垦改造成稻田后耕层土壤的N2O还原速率及其微生物机制却鲜有报道。选取崇明岛光滩湿地为对照（WK0），比较研究不同围垦年限（19、27、51、86 a）的围垦区稻田耕作层土壤N2O还原速率演替规律及其微生物数量变异特征。结果表明，土壤总有机碳含量（TOC）随围垦年限增长而显著增加，而土壤pH值、SO42-浓度和EC值则均随围垦年限增长而呈逐渐下降趋势。土壤N2O还原速率随围垦年限增长而显著增加，其中围垦86 a稻田土壤达到25.5 μg N2O·g-1·d-1，与光滩湿地相比增加了58.4%。定量PCR结果发现，功能基因nosZ Ⅰ和nosZ Ⅱ拷贝数也随着围垦年限增长而显著增加，其中围垦86 a的稻田土壤功能基因分别为1.72×108 copies·g-1和4.36×108 copies· g-1，比光滩湿地稻田高出一个数量级。相关性分析发现土壤N2O还原速率与功能基因nosZ Ⅰ拷贝数呈显著正相关，而功能基因nosZ Ⅱ拷贝数随围垦年限的增加率远高于功能基因nosZ Ⅰ；N2O还原速率、功能基因nosZ Ⅰ、nosZ Ⅱ拷贝数与3个土壤理化指标（pH、EC、SO42-）均呈负相关。因此，围垦造田促进了滨海湿地土壤N2O还原过程，而功能基因nosZ Ⅰ数量的大幅增加是N2O还原速率增加的重要原因。 |
| 英文摘要: |
| 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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