Non-linear response of soil N2O emissions to nitrogen fertiliser in a cotton-fallow rotation in sub-tropical Australia

Scheer, Clemens, Grace, Peter, & Rowlings, David (2016) Non-linear response of soil N2O emissions to nitrogen fertiliser in a cotton-fallow rotation in sub-tropical Australia. Soil Research, 54(5), pp. 494-499.

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Abstract

Nitrogen (N) fertiliser is a major source of atmospheric nitrous oxide (N2O), and over recent years there has been growing evidence for a non-linear, exponential relationship between N fertiliser application rate and N2O emissions. However, there is still a high level of uncertainty around the relationship of N fertiliser rate and N2O emissions for many cropping systems. We conducted year-round measurements of N2O emission and lint yield in four N-rate treatments (0, 90, 180 and 270 kg N ha–1) in a cotton–fallow rotation on a black vertosol in Australia. We observed a non-linear exponential response of N2O emissions to increasing N fertiliser rates with cumulative annual N2O emissions of 0.55, 0.67, 1.07 and 1.89 kg N ha–1 for the four respective N fertiliser rates, but no N response to yield occurred above 180 kg N ha–1. The annual N2O emission factors induced by N fertiliser were 0.13, 0.29 and 0.50% for the 90, 180 and 270 kg N ha–1 treatments respectively, significantly lower than the IPCC Tier 1 default value of 1.0%. This nonlinear response suggests that an exponential N2O emissions model may be more appropriate for estimating emission of N2O from soils cultivated to cotton in Australia. It also demonstrates that improved agricultural N-management practices can be adopted in cotton to substantially reduce N2O emissions without affecting yield.

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ID Code: 93890
Item Type: Journal Article
Refereed: Yes
Additional URLs:
DOI: 10.1071/SR14328
ISSN: 1838-675X
Subjects: Australian and New Zealand Standard Research Classification > ENVIRONMENTAL SCIENCES (050000) > SOIL SCIENCES (050300) > Carbon Sequestration Science (050301)
Australian and New Zealand Standard Research Classification > AGRICULTURAL AND VETERINARY SCIENCES (070000) > CROP AND PASTURE PRODUCTION (070300) > Agronomy (070302)
Australian and New Zealand Standard Research Classification > AGRICULTURAL AND VETERINARY SCIENCES (070000) > CROP AND PASTURE PRODUCTION (070300) > Crop and Pasture Nutrition (070306)
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Facilities: Science and Engineering Centre
Deposited On: 16 Mar 2016 04:05
Last Modified: 22 Sep 2016 04:38

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