- The emission factor for nitrous oxide (N2O) emissions from feed pads has been revised;
- This has reduced the reported emissions of the Australian feedlot sector by about 19 per cent; and
- This will help to direct future research and mitigation strategies.
Research jointly funded by Meat & Livestock Australia (MLA) and the Australian government has led to a big reduction in baseline greenhouse gas (GHG) emissions from the Australian feedlot sector.
This has followed a review of existing Australian research, which demonstrated that the default parameters used to calculate emissions from manure sources in Australian feedlots were not supported by peer-reviewed Australian research - and led to emissions being overestimated.
The Australian feedlot industry has invested in several research programs across more than a decade to understand emissions from manure sources, and assist the development of a revised emission factor for nitrous oxide (N2O) emissions from feed pads.
What lies beneath
An MLA-funded project completed by the Queensland Department of Agriculture, Fisheries and Forestry, and led by Matt Redding in conjunction with a University of Melbourne team led by Deli Chen, has significantly improved understanding of factors that control emissions in Australian feedlots.
Supported by MLA, a targeted review of research to date into the feedlot nitrogen (N) cycle - and specifically focusing on N2O emissions from manure pads - proposed the emission factor for these be revised down.
This would reflect industry practice and previous research findings.
The review was submitted to the Climate Change Division of the Commonwealth Department of Industry, Science, Energy and Resources and was adopted in the most recent National Inventory Report, which was published in April 2021.
Big steps for industry
The revision in the emission factor for N2O emissions from feed pads lowered the reported emissions of the Australian feedlot sector by 19 per cent.
Dr Stephen Wiedemann, of Integrity Ag & Environment, who led the review, said the implications of revising the emission factor for feed pads - and subsequent reduction to reported GHG emissions from the feedlot sector - were significant.
"The review of feedlot feed pad N2O emission research determined that the default emission factor previously used in the National Inventory Report for estimating GHG from feedlots was not supported by Australian research," he said.
"On average, Australian studies report 73pc lower emissions than the current Intergovernmental Panel on Climate Change (IPCC) inventory estimates."
Dr Wiedemann said emissions were not nearly as high as researchers thought they were.
"Manure nitrogen was found not to be the first limiting factor driving N2O emissions from the feed pad," he said.
"This will help direct future research and mitigation strategies.
"People use this data to make judgements about the industry, and we need to have knowledge to guide where research is directed, and where practice change can be undertaken."
For more information contact Joseph McMeniman