| 姚志生,王燕,王睿,刘春岩,郑循华.中国茶园N2O排放及其影响因素[J].农业环境科学学报,2020,39(4):715-725. |
| 中国茶园N2O排放及其影响因素 |
| Nitrous oxide emissions and controlling factors of tea plantations in China |
| 投稿时间：2020-02-08 |
| DOI：10.11654/jaes.2020-0137 |
| 中文关键词: 茶园 温室气体 氧化亚氮 施肥农田 排放系数 |
| 英文关键词: tea plantation greenhouse gas nitrous oxide fertilized cropland emission factor |
| 基金项目:国家自然科学基金项目（41977282，41675144，41305129） |
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| 摘要点击次数: 2039 |
| 全文下载次数: 2361 |
| 中文摘要: |
| 茶叶作为一种广受欢迎的天然饮料在中国经济和文化方面具有重要作用，但高氮肥投入的茶园种植系统也引起了一系列的环境问题，如土壤酸化和温室气体氧化亚氮（N2O）排放。迄今为止，尽管在茶园生态系统中已开展了一些田间观测研究，但对于中国茶园N2O排放总量及其影响因素仍缺乏全面的评估和量化。本研究基于田间观测研究的文献数据（共收集70个数据，其中包括45个常规施肥处理和25个不施肥处理）荟萃（Meta）分析，定量分析了基于环境因子（气候和土壤性质）和管理措施影响条件下中国茶园N2O年排放和直接排放系数（EFd）的变化特征。结果表明，中国茶园平均N2O年排放量为9.55 kg N·hm-2·a-1（95%置信区间为7.54~11.9 kg N·hm-2·a-1），高于我国粮食作物农田的排放；茶园的平均EFd为1.92%（95%置信区间为1.49%~2.39%），约是IPCC建议的全球农田N2O排放系数默认值1%的两倍。综合分析茶园N2O排放的影响因子表明，氮肥施用量是土壤N2O年排放量的关键驱动因素，且二者呈显著线性正相关关系。而EFd则主要受土壤C/N和黏粒含量的协同影响，且与二者呈显著负相关关系。基于中国茶园种植总面积（仅占<2%的中国农田总面积）和主要茶区的年平均氮肥施用量以及本研究的EFd，估算出2018年我国茶园N2O排放总量为28 Gg N·a-1，约占中国农田总排放量的15%。可见，茶园在中国农田种植系统中是大气N2O的强排放源。本研究进一步分析表明，茶园施用有机无机复混肥或新型肥料（如缓控释肥或添加生物炭），可有效地提高茶树的氮肥利用率并减少土壤N2O排放。 |
| 英文摘要: |
| Tea, as a popular beverage, plays an important role for local cultural and economic developments in China, but its cultivation with high amounts of nitrogen(N)application results in environmental degradation, such as soil acidification and high emissions of greenhouse gas nitrous oxide (N2O). So far, however, our understanding and quantification of total N2O emissions from tea plantations in China remain unclear, though several observations have been conducted at a site-level. Based on 70 datasets (including 45 and 25 datasets for fertilized and unfertilized treatments, respectively)extracted from in-situ field studies, we performed a comprehensive synthesis to characterize and quantify annual N2O emissions and direct emission factors(EFds)in dependence of environmental factors(i.e. climate and soil properties)and management practices across Chinese tea plantations. Results showed that mean annual N2O emissions across tea plantations in China were estimated to be 9.55 kg N·hm-2·a-1(with 95% confidence intervals of 7.54~11.9 kg N·hm-2·a-1), higher than those in Chinese major cereal croplands. Also, the analysis yields a mean EFd for tea in China equaled to 1.92%(with 95% confidence intervals of 1.49%~2.39%), being double as high as the IPCC default value of 1% for global crops. Across all the datasets, a regression analysis showed that N application rate was key factor driving annual N2O emissions, both exerting a significant positive linear correlation. While the EFd was mainly regulated by the combined effects of soil C/N ratio and clay content, i.e. EFd being strongly negatively correlated with soil C/N ratio and clay content. On basis of the current estimated mean EFd for tea, the tea planting area, and the N fertilizer application rate, total N2O emissions from Chinese tea plantations in 2018 were estimated to be approximately 28 Gg N·a-1, contributing up to 15% of total cropland N2O emissions. This suggested that although the area of tea was small(only accounting for <2% of Chinese total cropland area), tea plantations were hotspots of N2O emissions in the crop production sector. To address high emission characteristics of tea plantations, our results also revealed that applying the combination of synthetic and organic N fertilization, controlled-release fertilizers or biochar amendment to Chinese tea plantations was a promising management strategy for increasing N-use efficiency while effectively reducing soil N2O emissions. |
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