Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 13, issue 21
Biogeosciences, 13, 6095-6106, 2016
https://doi.org/10.5194/bg-13-6095-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 13, 6095-6106, 2016
https://doi.org/10.5194/bg-13-6095-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 07 Nov 2016

Research article | 07 Nov 2016

Urbanisation-related land use change from forest and pasture into turf grass modifies soil nitrogen cycling and increases N2O emissions

Lona van Delden, David W. Rowlings, Clemens Scheer, and Peter R. Grace Lona van Delden et al.
  • Institute for Future Environments (IFE), Queensland University of Technology (QUT), Brisbane, QLD, Australia

Abstract. Urbanisation is becoming increasingly important in terms of climate change and ecosystem functionality worldwide. We are only beginning to understand how the processes of urbanisation influence ecosystem dynamics, making peri-urban environments more vulnerable to nutrient losses. Brisbane in South East Queensland has the most extensive urban sprawl of all Australian cities. This research estimated the environmental impact of land use change associated with urbanisation by examining soil nitrogen (N) turnover and subsequent nitrous oxide (N2O) emissions using a fully automated system that measured emissions on a sub-daily basis. There was no significant difference in soil N2O emissions between the native dry sclerophyll eucalypt forest and an extensively grazed pasture, wherefrom only low annual emissions were observed amounting to 0.1 and 0.2kgN2Oha−1yr−1, respectively. The establishment of a fertilised turf grass lawn increased soil N2O emissions 18-fold (1.8kgN2Oha−1yr−1), with highest emissions occurring in the first 2 months after establishment. Once established, the turf grass lawn presented relatively low N2O emissions for the rest of the year, even after fertilisation and rain events. Soil moisture was significantly higher, and mineralised N accumulated in the fallow plots, resulting in the highest N2O emissions (2.8kgN2Oha−1yr−1) and significant nitrate (NO3) losses, with up to 63kgNha−1 lost from a single rain event due to reduced plant cover removal. The study concludes that urbanisation processes creating peri-urban ecosystems can greatly modify N cycling and increase the potential for losses in the form of N2O and NO3.

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Urbanisation is becoming increasingly important in terms of climate change and ecosystem functionality worldwide. Temperate turf grass lawns in peri-urban environments have been identified as strong greenhouse gas emitters, even comparable to intensive agriculture. Conversely, this study identified subtropical turf grass as reducing greenhouse gas emissions significantly shortly after an initial establishment phase, despite changing nitrogen cycling in peri-urban soils.
Urbanisation is becoming increasingly important in terms of climate change and ecosystem...
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