植物生态学报 ›› 2021, Vol. 45 ›› Issue (9): 1006-1023.DOI: 10.17521/cjpe.2021.0040

• 研究论文 • 上一篇    下一篇

冻融循环期间土壤氧化亚氮排放影响因素

高德才, 白娥()   

  1. 长白山地理过程与生态安全教育部重点实验室, 东北师范大学地理科学学院, 长春 130024
  • 收稿日期:2021-01-29 接受日期:2021-05-09 出版日期:2021-09-20 发布日期:2021-11-18
  • 通讯作者: 白娥
  • 作者简介:*(baie612@nenu.edu.cn)
    ORCID: 高德才: 0000-0003-0545-4020
  • 基金资助:
    国家重点研发项目(2019YFA0607301);国家自然科学基金(31901157);国家自然科学基金(41971058);中国博士后科学基金(2020T130088);吉林省自然科学基金(YDZJ202101ZYTS104);吉林省自然科学基金(20180520087JH)

Influencing factors of soil nitrous oxide emission during freeze-thaw cycles

GAO De-Cai, BAI E()   

  1. Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun 130024, China
  • Received:2021-01-29 Accepted:2021-05-09 Online:2021-09-20 Published:2021-11-18
  • Contact: BAI E
  • Supported by:
    National Key R&D Program of China(2019YFA0607301);National Natural Science Foundation of China(31901157);National Natural Science Foundation of China(41971058);China Postdoctoral Science Foundation(2020T130088);Natural Science Foundation of Jilin Province, China(YDZJ202101ZYTS104);Natural Science Foundation of Jilin Province, China(20180520087JH)

摘要:

全球气候变化可能会提高冻融循环时间、强度以及频率, 从而可能显著影响土壤氧化亚氮(N2O)排放。N2O是一种重要的温室气体, 但目前对冻融循环期间土壤N2O排放规律以及影响因素的了解还有限。为此, 该研究采用整合分析方法, 从已发表文献中收集了30篇关于冻融循环对土壤N2O通量和累积排放量影响的文献, 探究冻融循环在不同生态系统对N2O排放的影响, 从试验设置、土壤基本理化性质以及冻融循环格局等角度全面综合地探究其排放影响因素。该研究得出, 冻融循环能显著增加N2O通量、N2O累积排放量和硝化作用速率, 全球平均增幅分别为72.34%、143.25%和124.63%; 冻融循环也可增加反硝化作用速率, 全球平均增幅为162.56%; 与之相反, 冻融循环显著减少微生物生物量氮含量, 全球平均减幅为6.39%。不同生态系统土壤水热条件和基本理化性质差异可显著影响冻融循环对N2O排放的影响。当年平均气温超过5 ℃时, 冻融循环作用可显著提高N2O通量104.13%, 显著高于年平均气温为0-5 ℃ (25.56%)和小于0 ℃ (55.29%)时; 土壤湿度大于70%时, N2O通量增加109.17%, 显著高于土壤湿度为50%-70% (65.67%)和小于50% (20.37%)时的通量。土壤黏粒和养分含量越高的土壤区域, 冻融循环对N2O排放的提高幅度越大。在有植物存在时, 冻融循环可显著提高土壤N2O通量达91.21%, 高于无植物存在时的54.43%。土壤过筛和在冻融循环期间采集土壤都会增加冻融循环对N2O排放的影响。另外, 融化时间长, 冻结强度大和冻融循环频率高均可显著提高土壤N2O累积排放量对冻融循环的响应。当冻结温度低于-10 ℃时, 冻融循环对土壤N2O排放通量的增幅可达100.73%, 显著高于在冻结温度为-10- -5 ℃ (47.74%)和高于-5 ℃ (70.25%)时。主要原因是冻结强度高可促进土壤微生物和土壤结构释放更多的养分, 从而提高N2O的产生和排放。该研究结果有助于更好地理解土壤N2O对冻融循环的响应及其影响因素, 为更准确地预测未来全球气候变化对N2O排放影响提供科学数据支撑。

关键词: 冻融, 氧化亚氮(N2O), 微生物生物量, 全球气候变化, 反硝化作用

Abstract:

Aims Enhanced duration, intensity, and frequency of freeze-thaw cycles owing to global climate change may significantly affect soil nitrous oxide (N2O) emission. N2O is an important greenhouse gas, but our current understanding of soil N2O emission and its influencing factors during freeze-thaw cycles is still limited.

Methods Here, we adopted the meta-analysis method and collected 30 articles on the effects of freeze-thaw cycles on soil N2O flux and cumulative emission from peer-reviewed journal articles. Our objectives were to explore the effects of freeze-thaw cycles on N2O emissions in different ecosystems and to comprehensively explore the influencing factors from the perspectives of experimental settings, soil physical and chemical properties, and the patterns of freeze-thaw cycles.

Important findings Results showed that freeze-thaw cycles significantly increased N2O instantaneous emission, cumulative emission, and nitrification by 72.34%, 143.25%, and 124.63%, respectively. Freeze-thaw cycles also increased denitrification by 162.56%. Conversely, freeze-thaw cycles significantly decreased microbial biomass nitrogen by 6.39%. The effect of freeze-thaw cycles on N2O emission was significantly affected by the variations in soil microclimate and soil physical and chemical properties in different ecosystems. When the mean annual temperature (MAT) of a site exceeded 5 °C, freeze-thaw cycles could significantly enhance the N2O flux by 104.13%, which was significantly higher than that the effect at sites with MAT between 0-5 °C (25.56%) or less than 0 °C (55.29%). When soil moisture was greater than 70%, the increase of soil N2O flux caused by freeze-thaw cycles was 109.17%, which was significantly higher than that when soil moisture was between 50%-70% (65.67%) or less than 50% (20.37%). The higher soil clay and nutrient contents were, the greater the increase in N2O emission caused by freeze-thaw cycles became. Freeze-thaw cycles could significantly increase soil N2O flux by 91.21% in the presence of plants, which was higher than the effect in the absence of plants (54.43%). The impact of freeze-thaw cycles on N2O emission could be enhanced by soil sieving. In addition, soils sampled during the freeze-thaw cycling period showed more responses to freeze-thaw cycles than soils sampled during other times. The response of cumulative N2O emissions to freeze-thaw cycles was significantly improved by longer duration of thawing, higher intensity of freezing, and higher frequency of freeze-thaw cycles. When the freezing temperature was lower than -10 °C, freeze-thaw cycles could enhance soil N2O flux by 100.73%, which was significantly higher than the effect when the freezing temperature was between -10- -5 °C (47.74%) or more than -5 °C (70.25%). The main reason was that higher intensity of freezing could promote the release of more nutrients from soil microorganisms and soil structure, thereby increasing the production and emission of N2O. Overall, these results can help better understand the response of soil N2O to freeze-thaw cycles and its influencing factors, and provide scientific data for accurately predicting the impact of global climate change on N2O emission in the future.

Key words: freeze-thaw, nitrous oxide (N2O), microbial biomass, global climate change, denitrification