Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Discussion papers
https://doi.org/10.5194/bg-2019-281
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-2019-281
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 21 Aug 2019

Submitted as: research article | 21 Aug 2019

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Biogeosciences (BG).

Modelling Nitrification Inhibitor Effects on N2O Emissions after Fall and Spring-Applied Slurry by Reducing Nitrifier NH4+ Oxidation Rate

Robert F. Grant, Sisi Lin, and Guillermo Hernandez-Ramirez Robert F. Grant et al.
  • Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada T6G 2E3

Abstract. Reductions in N2O emissions from nitrification inhibitors (NI) are substantial, but remain uncertain because measurements of N2O emissions are highly variable and discontinuous. Mathematical modelling may offer an opportunity to estimate these reductions if the processes causing variability in N2O emissions can be accurately simulated. In this study, the effect of NI was simulated with a simple, time-dependent algorithm to slow NH4+ oxidation in the ecosystem model ecosys. Slower nitrification modelled with NI caused increases in soil NH4+ concentrations and reductions in soil NO3 concentrations and in N2O fluxes that were consistent with those measured following fall and spring applications of slurry over two years from 2014 to 2016. The model was then used to estimate direct and indirect effects of NI on seasonal and annual emissions. After spring slurry applications, NI reduced N2O emissions modelled and measured during the drier spring of 2015 (35 % and 45%) less than during the wetter spring of 2016 (53 % and 72 %). After fall slurry applications, NI reduced modelled N2O emissions by 58 % and 56 % during late fall in 2014 and 2015, and by 8 % and 33 % during subsequent spring thaw in 2015 and 2016. Modelled reductions were consistent with those from meta-analyses of other NI studies. Simulated NI activity declined over time, so that reductions in N2O emissions modelled with NI at an annual time scale were relatively smaller than those during emission events. These reductions were accompanied by increases in NH3 emissions and reductions in NO3 losses with NI that caused changes in indirect N2O emissions. With further parameter evaluation, the addition of this algorithm for NI to ecosys may allow emission factors for different NI products to be derived from annual N2O emissions modelled under diverse site, soil, land use and weather.

Robert F. Grant et al.
Interactive discussion
Status: open (until 10 Oct 2019)
Status: open (until 10 Oct 2019)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Robert F. Grant et al.
Robert F. Grant et al.
Viewed  
Total article views: 140 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
124 16 0 140 7 2 2
  • HTML: 124
  • PDF: 16
  • XML: 0
  • Total: 140
  • Supplement: 7
  • BibTeX: 2
  • EndNote: 2
Views and downloads (calculated since 21 Aug 2019)
Cumulative views and downloads (calculated since 21 Aug 2019)
Viewed (geographical distribution)  
Total article views: 92 (including HTML, PDF, and XML) Thereof 92 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 19 Sep 2019
Publications Copernicus
Download
Short summary
Nitrification inhibitors (NI) have been shown to reduce emissions of nitrous oxide (N2O), a potent greenhouse gas, from fertilizer and manure applied to agricultural fields. However difficulties in measuring N2O emissions limit our ability to estimate these reductions. Here we propose and test a mathematical model that may allow us to estimate these reductions under diverse site conditions. These estimates will be useful in determining emission factors for NI-amended fertilizer and manure.
Nitrification inhibitors (NI) have been shown to reduce emissions of nitrous oxide (N2O), a...
Citation