Sainur high res N2O Plosone 2015.pdf (321.34 kB)

High-resolution denitrification kinetics in pasture soils link N2O emissions to pH, and denitrification to C mineralization

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posted on 2023-05-03, 18:31 authored by Md Sainur Samad, Lars Bakken, Shahid Nadeem, Timothy Clough, Cecile DeKlein, Karl Richards, Gary Lanigan, Sergio Morales
Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C) mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand) using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O) and N2O/(N2O+N2) product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2μmol N/h/vial) were significantly associated with C mineralization (CO2μmol/h/vial) measured both under oxic (r2 = 0.62, p = 0.0015) and anoxic (r2 =


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© 2016 Samad et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


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Samad, M. S., Bakken, L. R., Nadeem, S., Clough, T. J., de Klein, C.A.M., Richards, K. G., Lanigan, G. J., & Morales, S. E. (2016). High-resolution denitrification kinetics in pasture soils link N2O emissions to pH, and denitrification to C mineralization. PLoS One, 11(3), e0151713. doi: 10.1371/journal.pone.0151713

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