Refining emissions from grassland peat soils
Patrick Tuohy, Owen Fenton, Lilian O’Sullivan, Conor Bracken (AGRIP)
Greenhouse gas emissions from grassland peat soils were previously estimated at approximately 9Mt CO₂e per annum, making this the highest-emitting category from the land use, land-use change and forestry sector (LULUCF). This estimate was based on assumptions regarding the drainage status of these soils. Teagasc research highlighted the nature of these assumptions and proposed refined emissions estimates, which have been incorporated into the updated EPA National Inventory Report (March 2024). These estimates have significantly altered the wider understanding of the emission profile and the management of these soils, currently and into the future.
The study offered new insights into the drainage status of grassland peat soils. It showed that the extent of peatland drained for agriculture had been thus far overestimated in national inventory reporting. Evidence for these emission savings were garnered by compiling decades of evidence related to the drainage status of peat soils and data from national scientific literature. This evidence enabled a more accurate figure for grassland peat drainage status to be used in the national inventory.
These findings have directly and significantly reduced the estimated emissions from grassland peat soils (and the LULUCF sector more broadly) by 5.1Mt CO₂e per annum (from 9Mt to 3.9Mt, equating to approximately 7.5% of the total national emissions from all sectors as previously estimated). This change will inform and have a considerable influence on future policy around such soils regarding their management, and their rewetting and restoration potential.
These findings have reduced estimated emissions by 5.1Mt
Contact: patrick.tuohy@teagasc.ie
Funding: Teagasc.
Impact pathway(s): Policy Influencing.
The Teagasc MACC: a pathway to emissions reduction
Gary Lanigan, Kevin Hanrahan, Karl Richards (CELUP)
Agriculture must reduce greenhouse gas (GHG) emissions by 25% by 2030. In addition, the EU has set a land use, land-use change and forestry (LULUCF) GHG reduction target for Ireland of 0.73Mt CO₂e by 2030. The Teagasc Marginal Abatement Cost Curve (MACC) was developed to identify the most cost-effective pathways to reduce agriculture and LULUCF GHG emissions, and to quantify the contribution that bioenergy could make to decarbonising the energy system.
Three scenarios of agricultural development over the 2021-2030 period were examined using the FAPRI-Ireland economic model. Two adoption levels of each mitigation measure were analysed, and MACCs were generated for agriculture, LULUCF and bioenergy. The analysis showed that the 25% reduction target is achievable, but only with high levels of adoption and relatively stable livestock numbers. EU LULUCF reduction targets could also be achieved with the higher levels of adoption.
Principal agriculture mitigation measures included: reduced finishing age; reducing N fertiliser; feed additives; increased dairy Economic Breeding Index; and diversification into organic farming, forestry or feedstock provision for biomethane.
The main measures for LULUCF were the management, respectively, of current forests, water tables on peat soils, and grasslands. Afforestation, particularly, is crucial for achieving net-zero by 2050. The majority of fossil fuel displacement is projected to be due to the use of wood biomass and the achievement of the Government’s target of replacing 10% of gas demand with biomethane by 2030. If achieved, bioenergy would contribute about 10% to decarbonisation of the energy system.
Contact: gary.lanigan@teagasc.ie
Other contributor: Forest, Environmental Research & Services (FERS) Limited for forestry carbon modelling.
Funding: Teagasc, Department of Agriculture, Food and the Marine.
Impact pathway(s): Technology Development & Adoption.
Enteric methane at grass: setting new baselines
Ben Lahart, Laurence Shalloo, Johnathan Herron, Charles Dwan, Hazel Costigan (AGRIP)
Methane emissions from enteric fermentation are a by-product of feed digestion within the animal’s rumen. Within the agriculture sector, they account for the majority of total greenhouse gas (GHG) emissions. Due to a lack of country-specific data, the national GHG inventory in Ireland uses an international default conversion factor to estimate the amount of methane produced by dairy cows at grass.
Research at Teagasc Moorepark has directly measured the amount of methane produced by grazing dairy cows. The results demonstrate a seasonal nature to methane output at grass, with the lowest values observed in the spring period. The lower enteric methane emissions observed in the spring are related to an increase in pasture quality during this period with low levels of fibre. As the grazing season progresses methane output increases in line with an increased fibre content in pasture. When all available data is accumulated from experiments conducted under Irish grazing conditions to date, the methane conversion factor is approximately 9% lower than currently used within the national GHG inventory.
This data will be used to help inform the methane conversion factor used within the national GHG inventory grazing dairy cows. This will enable for more accurate calculations of enteric methane output from dairy cows at a national level and allow policy makers to make better and more informed decisions when implementing strategies to reduce methane output. It is expected that these new enteric methane conversion factors for Irish grazing dairy cows will be included in the AgNav tool and EPA National Inventory in the near future.
Contact: ben.lahart@teagasc.ie
Other contributors: Tírlan; Kerry; Carbery; Ornua; Dairygold; Nutribio.
Funding: VistaMilk SFI Research Centre.
Impact pathway: Policy Influencing.
Feeding 3-NOP in Irish dairy systems
Hazel Costigan, Laurence Shalloo, Ben Lahart (AGRIP)
The majority of the agricultural sector’s total greenhouse gas emissions stem from enteric fermentation, a by-product of feed digestion within the animal’s rumen. As such, there is an urgent need to develop solutions to reduce enteric methane output. The inhibitor 3-nitrooxypropanol (3-NOP) has proven to reduce enteric methane output by up to 30% when fed indoors to dairy cows as part of a total mixed ration. However, no work has been conducted with the additive in Irish conditions with dairy cows.
Research at Teagasc Moorepark evaluated 3-NOP when fed to spring calving dairy cows across different scenarios. Results show that feeding 3-NOP to grazing lactating dairy cows after milking twice daily reduced enteric methane by 5%. This reduced output is due to the additive’s rapid metabolism within the rumen. Slightly greater reductions (-11%) were noted indoors in non-lactating dairy cows when top-dressed onto grass silage twice daily.
However, the greatest reductions (-22%) were observed when 3-NOP was mixed through grass silage using a mixer wagon and fed to non-lactating dairy cows, which is comparable to findings in international research. To demonstrate the application of 3-NOP at farm level, approximately 3,500 cows across 18 Teagasc Signpost dairy farms were successfully fed 3-NOP mixed with grass silage in the winter of 2023/2024.
Ultimately, this research can be used to guide policy on the mitigation potential of 3-NOP across different scenarios in the Irish dairy industry. This enables more accurate calculations of enteric methane output from dairy cows when fed 3-NOP and demonstrating its application at commercial farm level.
22% methane reduction from mixing 3-NOP through grass silage
Contact: hazel.costigan@teagasc.ie
Other contributors: All milk processors.
Funding: Science Foundation Ireland; Teagasc.
Impact pathway: Capacity Building.
Carbon footprint of Irish grain among lowest in the world
Donal O’Brien, John Spink, Gary Lanigan (CELUP)
Grain is an essential component of agricultural supply chains and is of strategic importance to Ireland’s large livestock industry. To date, the carbon footprint of grain has been estimated with global models, but none of these tools are representative of the Irish tillage sector, making it challenging for the sector to provide reliable data on the carbon footprint of grain.
Our research goal was to develop a bespoke life cycle assessment (LCA) model focused on the carbon footprint of Irish grains. The model adhered to international standards and computed emissions from on-farm and off-farm activities (e.g. fertiliser manufacture) until grains were sold from the farm. It used Teagasc research to determine agricultural emissions and carbon sequestration. This new LCA grain model was applied in conjunction with Tirlán Co-op to complete the first carbon footprint analysis of commercially grown Irish grains. Activity data was collected from 48 growers who were representative of Tirlán Co-op’s 1,100 grain growers in 2022.
This work demonstrated that the carbon footprints of Irish grains are amongst the best in the world. The results showed that the gross carbon footprint of Tirlán Co-op’s oats, wheat and barley crop were very low compared to other grain-producing regions in Europe and North America. Accounting for straw incorporation, the Teagasc LCA grain model substantially reduced the carbon footprint values for oats and brought some grower’s crops to or below net zero emissions. These findings prove that commercially grown Irish grain has a low carbon footprint. The outputs of this research will be integrated into AgNav, which will in time support the marketing of Irish-produced food and feed ingredients.
Contact: donal.mobrien@teagasc.ie
Other contributor: RSK ADAS Ireland.
Funding: Tirlán Co-op (LCA survey, grower identification, grower selection, and data validation).
Impact pathway: Technology Development & Adoption.
Manure management for national inventories
Cathal Buckley, Brian Moran, Trevor Donnellan (REDP)
In Ireland, we tend to rely on aggregate-level activity data for national inventory accounting. However, this doesn’t exist in relation to important farm level activity data that can influence ammonia and nitrous oxide emissions. These can include: method of slurry storage; duration animals are housed versus grazing outdoors; and when and how slurry is applied. Using data collected by the Teagasc National Farm Survey (NFS), an analysis was carried out of farms with bovine animals in the period 2017 to 2021.
The study provided reliable detail on the duration of bovine animal housing periods, the prevalence of different types of slurry and farmyard manure storage facilities, the proportion of manures generated by different animal types, the extent of seasonality of manure application and the extent to which various slurry application and manure storage methods are employed.
Results were presented at national, nitrate zone and farm system level basis over the study period. Findings indicate a significant transition to low-emission slurry spreading (LESS) methods over the study period. Results indicate that the aggregate volume of slurry applied via LESS has risen from 4% in 2017 to 48% in 2021.
This provides policymakers with critical information to update Ireland’s national inventory accounting system for gaseous emissions in agriculture. For example, without such activity data taken into account, ammonia emissions inventory estimates could be up to 18% higher than currently estimated.
It is important to be able to capture farmers’ changes to management practices in the greenhouse gas and ammonia emissions in the national inventory accounting systems. The NFS data can be used to measure, report and verify these changes.
48% of slurry in 2021 was applied via LESS compared to 4% in 2017
Contact: cathal.buckley@teagasc.ie
Funding: Teagasc core funding.
Impact pathway: Policy Influencing.
Clean extraction of plant proteins
Rahel Suchintita Das, Shay Hannon, Sheila Alves, Marco Garcia-Vaquero, Brijesh K. Tiwari (FOOD)
In recent years, a surge in demand for plant proteins has propelled the plant-based protein market to new heights. However, existing extraction methods are energy-intensive and reliant on chemicals. This project aims to capitalise on this expanding market by adopting a clean and sustainable approach to extract proteins from Irish-grown pulses such as faba bean, pea, and lupins.
Irish cultivated faba beans were used in this project. State-of-the art cavitation technologies were employed to obtain proteins from the faba bean powder using water as the solvent, without any thermal interventions and chemicals. Hydrodynamic cavitation for 35 minutes resulted in protein isolates with nearly 90% purity and 70% yield, while the conventional method, after 18 hours of strong alkali extraction, achieved 4% and 84% lesser purity and yield, respectively.
Additionally, cavitation-extracted proteins demonstrated improved techno-functional properties, including solubility and water-holding capacities, supporting their application in beverage formulations.
These achievements were disseminated through journal publications and an Invention Disclosure Form, complemented by active engagement with industry stakeholders, investors, and regulatory bodies at various networking events. With promising pilot-scale results, the methods are easily scalable for adoption by food and feed manufacturers, reducing dependence on soy protein imports. This initiative aligns seamlessly with Teagasc’s Climate Action Strategy 2020–2030, fostering the development of sustainable circular bio-refineries.
Contact: shay.hannon@teagasc.ie
Other contributor: University College Dublin.
Funding: Department of Agriculture, Food and the Marine; UCD Ad Astra Studentship; UCD-CSC Scholarship Scheme.
Impact pathways: Technology Development & Adoption; Capacity Building.