中国稻田CH4排放对施氮的响应及影响因素Meta分析
时间:2019-04-27 11:06 来源:毕业论文 作者:毕业论文 点击:次
| 中国稻田CH4排放对施氮的响应及影响因素: Meta分析摘要 稻田CH4排放是全球气候变暖的重要贡献因子，然而，氮素投入如何影响稻田CH4排放目前并不清楚。本文搜集整理了我国各主要稻区近20年的历史资料数据 (1995-2016)，使用Meta分析方法，定量分析了施氮对稻田CH4排放的影响。结果表明，铵态氮肥能够显著降低稻田CH4排放，但降幅仅为1.68%，而复合肥、铵态氮肥与有机肥混施及复合肥与有机肥混施均显著增加稻田CH4排放，增幅分别为78.78%、111.70%和72.29%。随着氮肥用量的增加，稻田CH4排放呈现先降低后增加的趋势。干湿交替灌溉条件下施氮促进稻田CH4排放量是淹水灌溉条件下CH4排放量的8.57倍。不同耕作方式下，稻田CH4排放对施氮的响应表现为旋耕>免耕>翻耕，增幅分别为143.76%、24.60% 和16.42%。秸秆还田条件下施氮促进稻田CH4排放量是秸秆移除条件下CH4排放量的11.86倍。施氮条件下，直播稻田CH4排放量是移栽稻田的1.74倍；籼稻稻田CH4排放量是粳稻稻田的8.40倍。在单季稻田，施氮显著降低稻田CH4排放，降幅为12.80%；而在水旱轮作稻田 (稻-麦/油) 和双季稻田 (稻-稻-绿肥/休闲)，施氮显著增加稻田CH4排放，增幅分别为13.43%、33.78%、50.68%和93.29%。在东北、华北和西南地区，施氮分别降低稻田CH4排放约13.93%、5.45% 和 23.35%；在长江中下游和华南地区，施氮分别增加稻田CH4排放约42.62% 和192.71%。因此，研究氮肥施用对稻田CH4排放的影响应综合考虑水肥管理、耕作栽培、种植模式及气候资源等因素。研究结果可为科学调控我国稻田CH4排放提供理论参考。34926 毕业论文关键词 稻田；甲烷排放；氮肥施用；Meta分析 Response of CH4 emissions to nitrogen application in rice paddy fields: A meta-analysis in China Abstract: Global warming is widely concerned, and CH4 emission makes important contribution to global warming in the rice paddy fields. Nitrogen application is one of the prerequisites to achieve high grain production of rice. However, it is less known how N application affects CH4 emissions in the rice paddy fields. Although many studies have been conducted to test the response of CH4 emissions to nitrogen application, high variation was reported and no consistent conclusion has been made at present. This study collected historical data (1995-2016) from the main rice growing districts in China, and quantitatively analyzed the response characteristics of CH4 emissions to nitrogen application with meta-analysis. It suggested that ammonium significantly reduced CH4 emissions by 1.68%. However, other fertilizers, including compound fertilizer, ammonium combined with organic fertilizer, compound fertilizer with organic fertilizer, greatly increased CH4 emissions by 78.78%、111.70% and 72.29%, respectively. CH4 emissions decreased first but then increased with increasing nitrogen input. It is 8.57 times for the response magnitude of CH4 emissions to nitrogen application under dry/wet alternative irrigation than under continuous flooding conditions. Under different tillage regimes, the response magnitude of CH4 emissions to nitrogen fertilization is as follows: rotary tillage>no tillage>ploughing tillage. The response magnitude of CH4 emissions to nitrogen under straw incorporation is 11.86 times of which under straw removal conditions. Under nitrogen application, CH4 emission in the seed-directed fields is 1.74 times for which under seedling transplanting fields; CH4 emission in the indica rice fields is 8.40 times for which in the japonica rice fields. In the single cropping rice systems, nitrogen significantly reduced CH4 emissions by 12.80%, but CH4 emissions were increased by 13.43%, 33.78%, 50.68% and 93.29% in the rice-wheat, rice-rape, rice-rice-legume and rice-rice-fallow systems, respectively. In the northeastern, northern and southwestern rice growing districts, nitrogen application significantly reduced CH4 emissions, while it significantly increased CH4 emissions in the middle and lower regions in the Yangtze River and South China. Thus, it is necessary to comprehensively consider the effects of water and nitrogen management, tillage and cultivation, farming system and climate on the response of CH4 to nitrogen applications. (责任编辑：qin) |