2021-11-10T15:59:58 n13213

Sources of nitrous oxide from intensively managed pasture soils

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Rainfall and irrigation trigger large pulses of the powerful greenhouse gas N2O from intensively managed pastures, produced via multiple, simultaneously occurring pathways. These N2O pulses can account for a large fraction of total N2O losses, demonstrating the importance to determine magnitude and source partitioning of N2O under these conditions.

Researchers investigated the response of different pathways of N2O production to wetting across three different textured pasture soils.  Soil microcosms were fertilised with an ammonium nitrate (NH4NO3) solution which was either single or double 15N labelled, wetted to four different water-filled pore space (WFPS) levels, and incubated over two days.

The use of a 15N pool mixing model together with soil N gross transformations enabled the attribution of N2O to specific pathways, and to express N2O emissions as a fraction of the underlying N transformation. Denitrification and nitrification mediated pathways contributed to the production of N2O in all soils, regardless of WFPS. Denitrification was the main pathway of N2O production accounting for > 50 % of cumulative N2O emissions even at low WFPS. The contribution of autotrophic nitrification to N2O emissions decreased with the amount of wetting, while the contribution of heterotrophic nitrification remained stable or increased. Following the hole-in-the-pipe model, 0.1 to 4% of nitrified N was lost as N2O, increasing exponentially with WFPS, while the percentage of denitrified N emitted as N2O decreased, providing critical information for the representation of N2O/WFPS relationships in simulation models.

Findings demonstrated that the wetting of pasture soils promotes N2O production via denitrification and via the oxidation of organic N substrates driven by high carbon and N availability upon wetting. The large contribution of heterotrophic nitrification to N2O emissions should be considered when developing N2O abatement strategies, seeking to reduce N2O emissions in response to rainfall and irrigation from intensively managed pastures.

The associated data for the study are available here. 

Geographical area of data collection

text
Incubation study with soils collected from three intensively managed pasture sites under dairy production in subtropical Australia: Site Casino Gympie Kerry Latitude -28.865 -26.19 -28.109 Longitude 152.874 152.74 153.031

Publications

Friedl, Johannes, Scheer, Clemens, Rosa, Daniele De, Müller, Christoph, Grace, Peter, & Rowlings, David W. (2021) Sources of nitrous oxide from intensively managed pasture soils: the hole in the pipe. Environmental Research Letters, 16(6), Article number: 065004. https://eprints.qut.edu.au/210233/

Research areas

Climate change
Dairy
Denitrification
Pastures
Greenhouse emissions

Cite this collection

Friedl, Johannes; (2021): Sources of nitrous oxide from intensively managed pasture soils. Queensland University of Technology. (Dataset) https://doi.org/10.25912/RDF_1631156805217

Partner institution

Karlsruher Institute for Technology, Garmisch https://www.imk-ifu.kit.edu/

Data file types

.docx (Word), .xlsx (Excel), and .pdf (PDF).

Licence


Creative Commons Attribution-NonCommercial-No Derivatives 4.0 (CC-BY-NC-ND)
http://creativecommons.org/licenses/by-nc-nd/4.0/

Copyright

© Johannes Friedl, 2021.

Dates of data collection

From 2015-08-01 to 2016-02-01

Connections

Has association with
Clemens Alfred Scheer  (Researcher)
David Rowlings  (Researcher)
Peter Grace  (Researcher)
Has chief investigator
Johannes Friedl  (Researcher)

Contacts

Other

Date record created:
2021-07-19T11:43:46
Date record modified:
2021-11-10T15:59:58
Record status:
Published - Open Access