Magnitude and Edaphic Controls of Nitrous Oxide Fluxes in Natural Forests at Different Scales

Forests

Jinzhi Wang¹  Kerou Zhang¹  Xiaoming Kang¹  Liang Yan¹  Yong Li¹  Xiaodong Zhang¹  Haidong Wu¹  Zhongqing Yan¹  Mingxu Li² 

[1] Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China;Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;

关键词: nitrous oxide fluxes;    edaphic environmental controls;    leaf trait;    field studies;   

DOI  :  10.3390/f11030251

来源: DOAJ

【 摘 要 】

Forest nitrous oxide (N₂O) emission plays an important role in the greenhouse gas budget of forest ecosystems. However, spatial variability in N₂O fluxes complicates the determination of key factors of N₂O fluxes at different scales. Based on an updated database of N₂O fluxes and the main edaphic factors of global forests, the magnitude of N₂O fluxes from forests and the relationships between edaphic factors and N₂O fluxes at different scales were analyzed. According to the results, the average annual N₂O flux of the global forest was 142.91 ± 14.1 mg N m⁻² year⁻¹. The range of total forest estimated N₂O emission was 4.45−4.69 Tg N in 2000. N₂O fluxes from forests with different leaf traits (broadleaved and coniferous) have significant differences in magnitude, whereas the leaf habit (evergreen and deciduous) was an important characteristic reflecting different patterns of N₂O seasonal variations. The main factors affecting N₂O fluxes on the global scale were ammonium (NH₄⁺) and nitrate (NO₃⁻) concentrations. With an increasing scale (from the site scale to the regional scale to the global scale), the explanatory power of the five edaphic factors to N₂O flux decreased gradually. In addition, the response curves of N₂O flux to edaphic factors were diversified among different scales. At both the global and regional scales, soil hydrothermal condition (water filled pore space (WFPS) and soil temperature) might not be the main spatial regulation for N₂O fluxes, whereas soil nutrient factors (particularly NO₃⁻ concentration) could contribute more on N₂O flux spatial variations. The results of site-control analysis demonstrated that there were high spatial heterogeneity of the main N₂O controls, showing N₂O fluxes from low latitude forests being more likely associated with soil WFPS and temperature. Thus, our findings provide valuable insights into the regulatory edaphic factors underlying the variability in N₂O emissions, when modeling at different scales.

【 授权许可】

Unknown