Rural
12 September, 2024
Crop GHG study comes to Wimmera
Horsham will host part of a new $8 million national study of greenhouse gas (GHG) emissions from crop residues.
The study, which will quantify emissions, is designed to help the Australian grains industry accurately report its carbon footprint, with potential benefits for future market access and price.
An initiative of the Grains Research and Development Corporation (GRDC), the national project will be led by Professor David Rowlings from the Queensland University of Technology (QUT) and will involve two years of field work to quantify emissions from crop residue decomposition across a range of crop types, climates and soils at five sites in Australia.
In addition to Horsham, trial sites will comprise Gatton (Queensland), Tamworth and Wagga Wagga (New South Wales) and Wongan Hills (Western Australia).
These sites will be co-ordinated and monitored by the project’s research partners Agriculture Victoria, the Western Australian Department of Primary Industries and Regional Development (DPIRD), the NSW Department of Primary Industries and Regional Development (NSW DPIRD) and the University of Queensland (UQ).
The landmark study is expected to have significant benefits for grain growers and marketers, as the GHG emissions attached to grains can affect the price and marketability of exports as well as the sustainability credentials of farm businesses.
Professor Rowlings said crop residues emitted GHG as they decomposed in the paddock, with nitrous oxide (N2O) making up most of these emissions.
“Australia includes these emissions in its sector-level accounting to the Intergovernmental Panel on Climate Change (IPCC),” he said.
“While the global default emission decomposition factor is 1 per cent of total residues, international research has shown that 0.5 per cent may be more accurate for dry climates.
“As this research has been accepted by the IPCC, CSIRO – with GRDC support – is currently updating Australia’s GHG baseline methodology to use the lower emissions factor from 2024.
“However, with approximately 23 million hectares of land under cropping, Australian growers could still benefit by being able to use accurate, locally derived emissions data for IPCC reporting.”
At each trial site, N2O will be measured for the 12 months following harvest to obtain accurate data on the emissions from decaying crop residues.
Crops being studied include wheat, faba beans and canola at Horsham and in NSW; maize, sorghum, wheat and faba beans in Queensland; and wheat and canola in WA.
“We've achieved a good spread of representative climate conditions, soil types and crops,” Professor Rowlings said.
“Over the two years and five locations, we will gather 32 site-years’ worth of data.”
GRDC Sustainable Cropping Systems manager – north, Cristina Martinez, said the new national study was critical in that it aimed to generate representative emissions factors for Australian crop residues alongside region-based data that individual farms could adopt for emissions accounting and reporting.
This research builds on earlier work done by GRDC in partnership with CSIRO for the Australian Grains Baseline and Mitigation Assessment.
This 2022 report showed crop residue accounted for 20.4 per cent of all on-farm GHG emissions in Australian cropping, compared to fertiliser (15 per cent) and lime application and farm operations (11 per cent each).
This initial study also concluded that the use of internationally derived emissions factors may be overestimating reportable GHG emissions from the Australian grains sector.
The new national study has a total investment of $8 million, including $4.6 million from GRDC.