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Alignment with SDGs
B. Lahart, k. Richards, J. Herron, T. Donnellan, L. Shalloo, F. Buckley, M. A. Fenelon Teagasc – the Agriculture and Food Development Authority in Ireland • Ireland
Ireland is at the forefront of a global research response on climate change initiatives in the agri-food sector. Its roadmap for action aims to halve greenhouse emissions by 2030 and reach net zero before 2050. The agriculture sector has been given a target of a 25% reduction by 2030. The route towards lower emissions includes an ambition to address circularity in Ireland’s bio-economy. While there are many ongoing research activities, this communication focuses on examples of methane reduction and soil carbon sequestration strategies as key climate actions relevant to the dairy and broader agriculture sectors.
The impact of selecting cows using the economic breeding index on methane output
The contribution of genetics to environmental impact, including methane production, is considerable, as breeding is cumulative, permanent and compounded with successive generations. Ireland has developed an economic breeding index (EBI) to identify animals that increase profitability in a pasture-based dairy system. However, all dairy cows are treated equally when enteric methane emissions are counted nationally through inventory models. These models assume that increased productivity through genetic selection increases feed intake, leading to greater enteric methane emissions. Methane emissions were measured between March and October 2021 in a group of high (Elite; EBI = €233) and national average EBI (Nat Av; EBI = €133) ( Table 1) animals. The Elite group had greater milk fat and protein %, which resulted in an 8% greater milk solids yield with no significant difference in methane emissions. Despite this, the methodology applied in the national inventory models calculated the Elite to emit significantly more methane per day compared to the Nat Av. This research highlights that further work is required to include genetic merit within inventory models. A new carbon sub-index will be incorporated into Ireland’s EBI later in 2022. This sub-index will rank animals based on greenhouse gas emissions and will be linked to the calculation of the EBI measure through a price per tonne of carbon. The revised EBI will emphasise traits which reduce carbon emissions, such as fertility and maintenance, allowing for savings in greenhouse emissions over the next decade.
SOIL CARBON SEQUESTRATION
Ireland has a dynamic research programme investigating carbon sequestration by soil. Grassland soils have been shown to contain large quantities of carbon, approximately 440 t CO2/ha or an estimated 1,800 Mt CO2 across all Irish mineral soils. Ireland’s national GHG emissions are about 60 Mt per year, meaning that mineral soils store equivalent to 30 years’ of emissions. Our peat soils store even more per ha, about 4,000 t CO2/ha. So while there are vast carbon stocks in Ireland’s soils, is there an ‘addition’ (sequestering) or ‘reduction’ of these stocks taking place over time?
Soil carbon sequestration is essential for removing carbon dioxide from the air and storing it in the soil while improving its health. Carbon stored in soils is often called soil organic carbon, and its benefits include improved workability, water holding capacity, and productivity. Ecosystems that can sequester more CO2 than they release are termed carbon sinks, while those that emit more than they sequester are termed carbon sources. Forestry is good for sequestering carbon, and agricultural soils can also be carbon sinks (but they can also be sources). Thus carbon sequestration is important, considering Ireland must be climate neutral by 2050.
Scientists at Teagasc are using computer modelling and flux towers to measure gaseous exchange above the soils. Given its importance to agricultural GHG balances, these are essential research tools for quantification, policy-making and farmer decision-making. The research shows that grasslands are generally a carbon sink, with values for carbon sequestration ranging from 1.5 to 4 t CO2 /ha/yr. In contrast to mineral soils, grasslands on drained organic (peat) soils are assumed to be a substantial source of CO2 of circa. 20 t CO2 /ha/yr. This is because they contain large carbon stocks (approx. 4,000 t CO2 per ha), and this is rapidly decomposed and released as CO2 upon draining. These soils are assumed to account for 5-6 Mt CO2 emissions in addition to the ~20 Mt CO2 from agriculture. Measuring and establishing robust emissions information and then restoring small areas of peat soils can deliver considerable CO2 savings. Research is currently focusing on establishing Irish-specific emission factors for soil carbon sequestration for inclusion in the national inventory. Through the National Agricultural Soil Carbon Observatory (see link below), the Agricultural Catchments programme, the Signpost farms, and the Science Foundation Ireland (Sfi) funded VistaMilk research centre, Ireland is developing an extensive European infrastructure to measure and report emissions. The research is also investigating a number of the measures in Table 2 to generate scientific data and advice for farmers that will see major improvements to the national greenhouse gas inventory. Emissions from the Land-use, Land-use change and forestry sectors have to be reduced in line with all sectors to assist Ireland in achieving the 51% greenhouse gas reduction target. While science improves the measurement of carbon and refinement of emission factors, the measures identified in Table 2 above will deliver on carbon savings now. Many of these measures improve incomes and agronomic yields, benefiting biodiversity and water quality.
Taking account of the science and policy targets, Ireland’s Signpost Farms initiative will drive the adoption of greenhouse gas mitigation actions on individual farms in Ireland. A cohort of farms has been selected, and their sustainability performance and adoption of mitigation actions are now being tracked through time. These farms will then serve as:
• a proving ground for real-world imple-mentation of greenhouse gas mitigation actions and;
• a peer-to-peer learning platform for the wider farm population designed to promote more widespread adoption of these mitigation actions.