The recent practice in annual reporting on agricultural land use is "at odds with its cropland history", which could lead to inaccuracies in greenhouse gas accounting, according to new research from scientists at Trinity College Dublin. In Ireland, 90% of agricultural land is categorised as pasture land, with only a small proportion of arable land. However, this view on Irish land use needs to be re-evaluated, according to the researchers.
The recent practice in annual reporting on agricultural land use is "at odds with its cropland history", which could lead to inaccuracies in greenhouse gas accounting, according to new research from scientists at Trinity College Dublin.
In Ireland, 90% of agricultural land is categorised as pasture land, with only a small proportion of arable land. However, this view on Irish land use needs to be re-evaluated, according to the researchers.
Published in the journal Land Use Policy, the research is an in-depth analysis using the geographic database developed to assist farmers and authorities with the Single Farm Payment scheme.
"We found that agricultural land use in Ireland is much more dynamic than annual reports suggest," said Dr Jesko Zimmerman, research fellow in botany at Trinity.
"While the area annually reported as cropland was on average 3,752km sq, this area has been shifting around the country. In the 12 years for which data was available (2000 to 2012), only about half of that area could be considered permanent cropland (1,252 km sq). In contrast, the area that showed arable history in the timeframe was 7,373km sq," he said.
Zimmermann claims that relying on annual data, and not including land-use history, led to an underestimation of area reported as cropland by 45.7% in the 2008 to 2012 greenhouse gas commitment period set in the Kyoto protocol.
"The research should have major implications for policy, with the new Paris Agreement fresh in our minds."
Zimmermann collaborated with Teagasc among many others in this research.
Land-use change
The Department of Agriculture said that while it welcomes any research which contributes to improving our inventory systems, this research relates to cropland management emissions, which come under land use, land-use change and forestry (LULUCF), and are not reported or accounted as agriculture emissions.
"It should be noted that land use, land-use change and forestry emissions do not form part of the current EU effort sharing decision (ESD) therefore, we do not get either credits or debits for LULUCF," a Department spokesperson told the Irish Farmers Journal.
The Department added that by contrast, emissions of methane and nitrous oxide from Irish agriculture are reported under EU effort sharing.
"While the overall cropland area is reasonably static, it does not reflect the inter-annual changes in cropland area, ie the land use change which occurs," the Department said.
Meanwhile, IFA environment chair Harold Kingston told the Irish Farmers Journal that Teagasc should be asked to review this research, "to know exactly where we stand".
"It is an interesting study, but we need to look at the whole picture. The 28 EU heads of state and governments recognise the multiple roles of agriculture, and that the measuring of greenhouse gas emissions can sometimes ignore crop rotation, which is good for soil health and biodiversity," he said.
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