Nitrogen transformation rates and N2O producing pathways in two pasture soils
Better understanding of N transformations and the regulation of N2O-related N transformation processes in pasture soil contributes significantly to N fertilizer management and development of targeted mitigation strategies.
Materials and methods
15N tracer technique combined with acetylene (C2H2) method was used to measure gross N transformation rates and to distinguish pathways of N2O production in two Australian pasture soils. The soils were collected from Glenormiston (GN) and Terang (TR), Victoria, Australia, and incubated at a soil moisture content of 60% water-filled pore space (WFPS) and at temperature of 20 °C.
Results and discussion
Two tested pasture soils were characterized by high mineralization and immobilization turnover. The average gross N nitrification rate (ntot) was 7.28 mg N kg−1 day−1 in TR soil () and 5.79 mg N kg−1 day−1 in GN soil. Heterotrophic nitrification rates (nh), which accounting for 50.8 and 41.9% of ntot, and 23.4 and 30.1% of N2O emissions in GN and TR soils, respectively, played a role similar with autotrophic nitrification in total nitrification and N2O emission. Denitrification rates in two pasture soils were as low as 0.003–0.004 mg N kg−1 day−1 under selected conditions but contributed more than 30% of N2O emissions.
Results demonstrated that two tested pasture soils were characterized by fast N transformation rates of mineralization, immobilization, and nitrification. Heterotrophic nitrification could be an important NO3−–N production transformation process in studied pasture soils. Except for autotrophic nitrification, roles of heterotrophic nitrification and denitrification in N2O emission in two pasture soils should be considered when developing mitigation strategies.
KeywordsAcetylene Autotrophic nitrification Denitrification Heterotrophic nitrification Immobilization Mineralization
This work received financial support from Incitec Pivot, the Australian Government Department of Agriculture through the Grains Research and Development Corporation, Australian Research Council (DE150100870, DP160101028, and LP160101134), National Natural Science Foundation of China (41501243), and the State Key Laboratory of Soil and Sustainable Agriculture (Y20160031).
- AGO (2010) National Greenhouse Account, National Inventory Report 2008, volume 2. Australian Greenhouse Office, Commonwealth of Australia, CanberraGoogle Scholar
- Bouwman AF, Boumans LJM, Batjes NH (2002) Emissions of N2O and NO from fertilized fields: summary of available measurement data. Glob Biogeochem Cycles 16:1058Google Scholar
- Braker G, Conrad R (2011) Diversity, structure, and size of N2O-producing microbial communities in soils—what matters for their functioning? In: Laskin AI, Sariaslani S, Gadd GM (eds) Advances in applied microbiology, vol 75. Advances in applied microbiology. Elsevier Academic Press Inc, San Diego, pp 33–70CrossRefGoogle Scholar
- Chen ZM, Ding WX, Xu YH, Müller C, Rütting T, Yu HY, Fan JL, Zhang JB, Zhu TB (2015) Importance of heterotrophic nitrification and dissimilatory nitrate reduction to ammonium in a cropland soil: evidences from a 15N tracing study to literature synthesis. Soil Biol Biochem 91:65–75CrossRefGoogle Scholar
- del Prado A, Merino P, Estavillo JM, Pinto M, Gonzalez-Murua C (2006) N2O and NO emissions from different N sources and under a range of soil water contents. Nutr Cycl Agroecosyst 74:229–243Google Scholar
- Fernandez LA, Bedmar EJ, Sagardoy MA, Delgado MJ, Gomez MA (2011) Denitrification activity in soils for sustainable agriculture. In: Maheshwari DK (ed) Bacteria in agrobiology: plant nutrient management. Springer, Berlin Heidelberg, pp 321–338Google Scholar
- Garrido F, Henault C, Gaillard H, Perez S, Germon JC (2002) N2O and NO emissions by agricultural soils with low hydraulic potentials. Soil Biol Biochem 34:559–575Google Scholar
- Hart SC, Stark JM, Davidson EA, Firestone MK (1994) Nitrogen mineralization, immobilization, and nitrification. In: Weaver RW, Angle S, Bottomley P, Bezdicek D, Smith S, Tabatabai A, Wollum A (ed) Methods of soil analysis. Part 2. Microbiological and Biochemical properties. SSSA Book Series, Madison, pp 985–1018Google Scholar
- IPCC (1996) Climate change 1995, the science of climate change. Contribution of working group 1 to the second assessment report of the Intergovernmental Panel on Climate Change. Cambridge University Press, CambridgeGoogle Scholar
- IPCC (2007) Climate change 2007: the physical science basis. In: Solomon S, Qin D, Manning M (eds) Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge University Press, CambridgeGoogle Scholar
- Klemedtsson L, Svensson BH, Lindberg T, Rosswall T (1977) The use of acetylene inhibition of nitrous oxide reductase in quantifying denitrification in soils. Swed J Agric Res 7:179–185Google Scholar
- Lan T, Han Y, Roelcke M, Nieder R, Cai Z (2013) Processes leading to N2O and NO emissions from two different Chinese soils under different soil moisture contents. Plant Soil 371:611–627Google Scholar
- Liu SW, Lin F, Wu S, Ji C, Sun Y, Jin YG, Li SQ, Li ZF, Zou JW (2017) A meta-analysis of fertilizer-induced soil NO and combined NO+N2O emissions. Glob Chang Biol 23:2520–2532Google Scholar
- Müller C, Laughlin RJ, Spott O, Rütting T (2014) Quantification of N2O emission pathways via a 15N tracing model. Soil Biol Biochem 72:44–54Google Scholar
- Pedersen H, Dunkin KA, Firestone MK (1999) The relative importance of autotrophic and heterotrophic nitrification in a conifer forest soil as measured by 15N tracer and pool dilution techniques. Biogeochemistry 44:135–150Google Scholar
- Verhagen FJM, Laanbroek HJ (1991) Competition for ammonium between nitrifying and heterotrophic bacteria in dual energy-limited chemostats. Appl Environ Microbiol 57:3255–3263Google Scholar
- Vitousek PM, Aber JD, Howarth RW, Likens GE, Matson PA, Schindler DW, Schlesinger WH, Tilman DG (1997) Human alteration of the global nitrogen cycle: sources and consequences. Ecol Appl 7:737–750Google Scholar
- Wu D, Koster JR, Cardenas LM, Bruggemann N, Lewicka-Szczebak D, Bol R (2016) N2O source partitioning in soils using N-15 site preference values corrected for the N2O reduction effect. Rapid Commun Mass Spectrom 30:620–626Google Scholar