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Biochar amendment suppresses N 2 O emissions but has no impact on 15 N site preference in an anaerobic soil
Author(s) -
Hyodo Ayumi,
Malghani Saadatullah,
Zhou Yong,
Mushinski Ryan M.,
Toyoda Sakae,
Yoshida Naohiro,
Boutton Thomas W.,
West Jason B.
Publication year - 2018
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8305
Subject(s) - biochar , amendment , chemistry , acetylene , soil water , denitrification , environmental chemistry , incubation , nitrogen , slash and char , pyrolysis , organic chemistry , soil science , environmental science , biochemistry , political science , law
Rationale Biochar amendments often decrease N 2 O gas production from soil, but the mechanisms and magnitudes are still not well characterized since N 2 O can be produced via several different microbial pathways. We evaluated the influence of biochar amendment on N 2 O emissions and N 2 O isotopic composition, including 15 N site preference (SP) under anaerobic conditions. Methods An agricultural soil was incubated with differing levels of biochar. Incubations were conducted under anaerobic conditions for 10 days with and without acetylene, which inhibits N 2 O reduction to N 2 . The N 2 O concentrations were measured every 2 days, the SPs were determined after 5 days of incubation, and the inorganic nitrogen concentrations were measured after the incubation. Results The SP values with acetylene were consistent with N 2 O production by bacterial denitrification and those without acetylene were consistent with bacterial denitrification that included N 2 O reduction to N 2 . There was no effect of biochar on N 2 O production in the presence of acetylene between day 3 and day 10. However, in the absence of acetylene, soils incubated with 4% biochar produced less N 2 O than soils with no biochar addition. Different amounts of biochar amendment did not change the SP values. Conclusions Our study used N 2 O emission rates and SP values to understand biochar amendment mechanisms and demonstrated that biochar amendment reduces N 2 O emissions by stimulating the last step of denitrification. It also suggested a possible shift in N 2 O‐reducing microbial taxa in 4% biochar samples.