Biochar increases soil N2O emissions produced by nitrification-mediated pathways
Biochar increases soil N2O emissions produced by nitrification-mediated pathways
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DOI：
10.3389/fenvs.2014.00025
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发表时间：
2014-01-01
影响因子：
4.6
通讯作者：
Cayuela, Maria L.
中科院分区：
文献类型：
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作者：
Sanchez-Garcia, Maria;Roig, Asuncion;Cayuela, Maria L.
尽管许多研究报告减少土壤一氧化二氮（N2O）的排放量后，生物炭的修正，仍然缺乏了解的过程。因此，这一问题仍然存在争议，许多研究表明，在土壤中施用生物炭后，N2O排放量没有变化，甚至有所增加。解开这些变化的确切原因，以及在何种情况下生物炭减少或增加排放，对于制定和应用成功的缓解战略至关重要。为此，我们研究了两种土壤[Haplic黑土（HP）和Haplic钙土（HC）]，这表明相反的反应生物炭的修正。在相同的实验条件下，除了生物炭的土壤HP减少了76%的N2O排放量，而它增加了54%的土壤HC的排放量。我们结合微观实验，添加不同的氮肥，稳定同位素技术和使用硝化抑制剂（二环己二胺），目的是提高我们的理解，在这两种土壤中N2O的形成机制。研究表明，反硝化作用是导致土壤HP中N2O排放的主要途径，氨氧化和硝化反硝化作用是土壤HC中N2O的主要产生过程。生物质炭系统地促进了土壤HC的硝化作用，这可能是导致N2O排放增加的原因。在这里，我们证明了使用生物炭减少N2O排放量的有效性，从一个特定的土壤是连接到其占主导地位的N2O形成途径。
In spite of the numerous studies reporting a decrease in soil nitrous oxide (N2O) emissions after biochar amendment, there is still a lack of understanding of the processes involved. Hence the subject remains controversial, with a number of studies showing no changes or even an increase in N2O emissions after biochar soil application. Unraveling the exact causes of these changes, and in which circumstances biochar decreases or increases emissions, is vital to developing and applying successful mitigation strategies. With this objective, we studied two soils [Haplic Phaeozem (HP) and Haplic Calcisol (HC)], which showed opposed responses to biochar amendment. Under the same experimental conditions, the addition of biochar to soil HP decreased N2O emissions by 76%; whereas it increased emissions by 54% in soil HC. We combined microcosm experiments adding different nitrogen fertilizers, stable isotope techniques and the use of a nitrification inhibitor (dicyciandiamide) with the aim of improving our understanding of the mechanisms involved in the formation of N2O in these two soils. Evidence suggests that denitrification is the main pathway leading to N2O emissions in soil HP, and ammonia oxidation and nitrifier-denitrification being the major processes generating N2O in soil HC. Biochar systematically stimulated nitrification in soil HC, which was probably the cause of the increased N2O emissions. Here we demonstrate that the effectiveness of using biochar for reducing N2O emissions from a particular soil is linked to its dominant N2O formation pathway.