Nitrous oxide (N2O)-reducing denitrifier-inoculated organic fertilizer mitigates N2O emissions from agricultural soils
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The only known sink for nitrous oxide (N2O) is biochemical reduction to dinitrogen (N2) by N2O reductase (N2OR). We hypothesized that the application of N2O-reducing denitrifier-inoculated organic fertilizer could enhance soil N2O consumption while the disruption of nosZ genes could result in inactivation of N2O consumption. To test such hypotheses, a denitrifier-inoculated granular organic fertilizer was applied to both soil microcosms and fields. Of 41 denitrifier strains, 38 generated 30N2 in the end products of denitrification (30N2 and 46N2O) after the addition of Na15NO3 in culture condition, indicating their high N2O reductase activities. Of these 41 strains, 18 were screened in soil microcosms after their inoculation into the organic fertilizer, most of which were affiliated with Azospirillum and Herbaspirillum. These 18 strains were nutritionally starved to improve their survival in soil, and 14 starved and/or non-starved strains significantly decreased N2O emissions in soil microcosms. However, the N2O emission had not been decreased in soil microcosms after inoculating with a nosZ gene-disruptive strain, suggesting that N2O reductase activity might be essential for N2O consumption. Although the decrease of N2O was not significant at field scales, the application of organic fertilizer inoculated with Azospirillum sp. TSH100 and Herbaspirillum sp. UKPF54 had decreased the N2O emissions by 36.7% in Fluvisol and 23.4% in Andosol in 2014, but by 21.6% in Andosol in 2015 (H. sp. UKPF54 only). These results suggest that the application of N2O-reducing denitrifier-inoculated organic fertilizer may enhance N2O consumption or decrease N2O emissions in agricultural soils.
KeywordsClimate change Greenhouse gas Microbiological manipulation Mitigation technology Nitrous oxide consumption and sink Nitrous oxide reductase
We thank Shigeto Otsuka for his helpful discussion and Chie Hayakawa for her help with gas sampling in the fields. We also thank the technical staffs from the Niigata Agricultural Research Institute and the Institute for Sustainable Agro-ecosystem Services, The University of Tokyo for their assistance with field work. This study was supported by the Japan Society for the Promotion of Science through a Postdoctoral Fellowship (14F04390), the Program for Promotion of Basic and Applied Researches for Innovations in Bio-oriented Industry, and the Science and Technology Research Promotion Program for Agriculture, Forestry, Fisheries and Food Industry (26037B and 27004C), Japan.
- Felgate H, Giannopoulos G, Sullivan MJ, Gates AJ, Clarke TA, Baggs E, Rowley G, Richardson DJ (2012) The impact of copper, nitrate and carbon status on the emission of nitrous oxide by two species of bacteria with biochemically distinct denitrification pathways. Environ Microbiol 14:1788–1800CrossRefPubMedGoogle Scholar
- Gao N, Shen WS, Kakuta H, Tanaka N, Fujiwara T, Nishizawa T, Takaya N, Nagamine T, Isobe K, Otsuka S, Senoo K (2016) Inoculation with nitrous oxide (N2O)-reducing denitrifier strains simultaneously mitigates N2O emission from pasture soil and promotes growth of pasture plants. Soil Biol Biochem 97:83–91CrossRefGoogle Scholar
- Greenhouse Gas Inventory Office of Japan (GIO), Center for Global Environmental Research (CGER), National Institute for Environmental Studies (NIES) (2012) National Greenhouse Gas Inventory Report of Japan 2012. http://www-gio.nies.go.jp/aboutghg/nir/2012/NIR-JPN-2012-v3.0E.pdf
- IPCC (2013) Observations: atmosphere and surface. In: Stocker TF, Qin D, Plattner GK, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: the physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, pp 159–254Google Scholar
- Klein CAM, Harvey MJ (2012) Nitrous oxide chamber methodology guidelines. Ministry of Primary Industries, Wellington, New ZealandGoogle Scholar
- Sanford RA, Wagner DD, Wu QZ, Chee-Sanford JC, Thomas SH, Cruz-García C, Rodríguez G, Massol-Deyá A, Krishnani KK, Ritalahti KM, Nissen S, Konstantinidis KT, Löffler FE (2012) Unexpected nondenitrifier nitrous oxide reductase gene diversity and abundance in soils. Proc Natl Acad Sci U S A 109:19709–19714CrossRefPubMedPubMedCentralGoogle Scholar