“Hot spots” of N and C impact nitric oxide, nitrous oxide and nitrogen gas emissions from a UK grassland soil
Date
2017-07-03
Journal Title
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Publisher
Elsevier
Abstract
Agricultural soils are a major source of nitric- (NO) and nitrous oxide (N2O), which are produced and consumed
by biotic and abiotic soil processes. The dominant sources of NO and N2O are microbial nitrification and denitrification,
and emissions of NO and N2O generally increase after fertiliser application.
The present study investigated the impact of N-source distribution on emissions of NO and N2O from soil and
the significance of denitrification, rather than nitrification, as a source of NO emissions. To eliminate spatial
variability and changing environmental factors which impact processes and results, the experiment was conducted
under highly controlled conditions. A laboratory incubation system (DENIS) was used, allowing simultaneous
measurement of three N-gases (NO, N2O, N2) emitted from a repacked soil core, which was combined
with 15N-enrichment isotopic techniques to determine the source of N emissions.
It was found that the areal distribution of N and C significantly affected the quantity and timing of gaseous
emissions and 15N-analysis showed that N2O emissions resulted almost exclusively from the added amendments.
Localised higher concentrations, so-called hot spots, resulted in a delay in N2O and N2 emissions causing a longer
residence time of the applied N-source in the soil, therefore minimising NO emissions while at the same time
being potentially advantageous for plant-uptake of nutrients. If such effects are also observed for a wider range
of soils and conditions, then this will have major implications for fertiliser application protocols to minimise
gaseous N emissions while maintaining fertilisation efficiency.
Description
Publication history: Accepted - 6 June 2017; Published online - 3 July 2017.
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Article
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Keywords
Denitrification, Flow-through system, Isotopes, Nitrogen cycle, Greenhouse gas (GHG) emissions
Citation
Loick, N., Dixon, E., Abalos, D., Vallejo, A., Matthews, P., McGeough, K., Watson, C., Baggs, E. M. and Cardenas, L. M. (2017) ‘“Hot spots” of N and C impact nitric oxide, nitrous oxide and nitrogen gas emissions from a UK grassland soil’, Geoderma, 305, pp. 336–345. doi: 10.1016/j.geoderma.2017.06.007.