Contributions of nitrification and denitrification to N2O emissions from soils at different water-filled pore space
Contributions of nitrification and denitrification to N2O emissions from soils at different water-filled pore space
复制标题
DOI：
10.1007/s00374-005-0858-3
复制
发表时间：
2005-08-01
影响因子：
6.5
通讯作者：
Baggs, EM
中科院分区：
文献类型：
--
作者：
Bateman, EJ;Baggs, EM
首次采用稳定同位素与乙炔（0.01% v/v）抑制技术相结合的方法，测定了施肥（200 kg N ha(-1)）粉壤土在不同（20-70%）充水孔隙（WFPS）条件下反硝化、自养硝化和异养硝化过程中的N2O产量。（NH4NO3）- n -14- n -15重复的N-15-N2O排放量归因于反硝化作用，(NH4NO3)- n -15- n -15重复的N-15-N2O排放量减去(NH4NO3)- n -14- n -15重复的N-15-N2O排放量归因于乙炔存在下的硝化和异养硝化作用，因为没有异化硝酸盐还原成铵或N-15-NO3-的固定和再矿化。在24天内，以70% WFPS （31.6 mg N2O- n m(-2)）排放的所有N2O；1.12 μ g N2O-N g干土（-1）；在35-60% WFPS条件下，硝化作用是产生N2O的主要过程，占60% WFPS条件下排放N-15-N2O的81%，50% WFPS条件下异养硝化在7天内估计排放了7.9 μ g N-15-N2O m(-2) （0.28 ng N-15-N2O g干土（-1）），占该处理N-15-N2O的20%。在20% WFPS （2.6 μ g N-15-N2O m(-2)）条件下，7天内反硝化是主要的n2o生成过程；0.09 ng N-15-N2O g干土（-1）；85%的（15）pN-N2O来自该处理)，可能是由于该WFPS发生了好氧反硝化作用。我们的研究结果证明了稳定同位素和乙炔相结合的方法在量化不同过程的N2O排放方面的有效性，并表明根据土壤WFPS，几种过程可能对农业土壤的N2O排放有贡献。
A combination of stable isotope and acetylene (0.01% v/v) inhibition techniques were used for the first time to determine N2O production during denitrification, autotrophic nitrification and heterotrophic nitrification in a fertilised (200 kg N ha(-1)) silt loam soil at contrasting (20-70%) water-filled pore space (WFPS). N-15-N2O emissions from (NH4NO3)-N-14-N-15 replicates were attributed to denitrification and N-15-N2O from (NH4NO3)-N-15-N-15 minus that from (NH4NO3)-N-14-N-15 replicates was attributed to nitrification and heterotrophic nitrification in the presence of acetylene, as there was no dissimilatory nitrate reduction to ammonium or immobilisation and remineralisation of N-15-NO3-. All of the N2O emitted at 70% WFPS (31.6 mg N2O-N m(-2) over 24 days; 1.12 mu g N2O-N g dry soil(-1); 0.16% of N applied) was produced during denitrification, but at 35-60% WFPS nitrification was the main process producing N2O, accounting for 81% of N-15-N2O emitted at 60% WFPS, and 7.9 mu g N-15-N2O m(-2) (0.28 ng N-15-N2O g dry soil(-1)) was estimated to be emitted over 7 days during heterotrophic nitrification in the 50% WFPS treatment and accounted for 20% of N-15-N2O from this treatment. Denitrification was the predominant N2O-producing process at 20% WFPS (2.6 mu g N-15-N2O m(-2) over 7 days; 0.09 ng N-15-N2O g dry soil(-1); 85% of (15)pN-N2O from this treatment) and may have been due to the occurrence of aerobic denitrification at this WFPS. Our results demonstrate the usefulness of a combined stable isotope and acetylene approach to quantify N2O emissions from different processes and to show that several processes may contribute to N2O emission from agricultural soils depending on soil WFPS.