- Area of drained grassland peat soils is grossly overestimated
- Summary of the EPA Green House Gas Projections 2022 - 2040
- Get Ready to Sow Your Cover Crop
- Update from Signpost Demonstration Dairy Farmers
- Clover150 Programme Update
- Irish products ‘RumenGlas’ and ‘GasAbate’ generating promising results in reducing methane emissions
- Reducing Nitrogen Loss from Tillage Ground
- Hedgerow Sequestration
- The New Sustainability Digital Platform
- Reducing GHG Emissions in Sheep Systems
- Multi Species Swards
- Promising results from Ireland’s first large scale measurement of methane emissions in beef cattle
- Slurry Additives Research Programme at Teagasc, Johnstown Castle
- Ammonium-Based Compound Fertilisers Mitigate Nitrous Oxide Emissions in Temperate Grassland
- Green Feed Machine
- Quotas and Emissions
- Increasing soil pH reduces fertiliser derived N2O emissions
- High EBI cows have lower greenhouse gas emissions and favourable N efficiency
Irish products ‘RumenGlas’ and ‘GasAbate’ generating promising results in reducing methane emissions
Agriculture is responsible for 37% of Ireland's Greenhouse Gas (GHG) emissions with methane accounting for 68% of all Irish Agri GHGs. Mitigating methane emissions is recognised as the quickest way to slow down the impact of climate change, with Ireland committing to reduce agri GHG emissions by 25% by 2030. In Ireland, approximately 93% of methane emissions are derived from the digestion of feed in cattle and sheep and gaseous emissions from stored slurry. GlasPort Bio, a Galway-based company, have developed solutions to achieve this. ‘GasAbate’, an additive added to stored slurry, can reduce methane emissions from slurry by greater than 80%, while also reducing other harmful gas emissions such as ammonia and hydrogen sulphide. Treated slurry becomes a more effective fertiliser allowing farmers to reduce spend on chemical fertiliser, and greatly improves biogas yields when used in anaerobic digestion. They have also developed ‘RumenGlas’, a feed additive to greatly reduce methane emissions from livestock. In trials conducted in Teagasc Grange, preliminary results suggest methane emissions reductions of 30% while allowing dramatic increases in animal performance – with finishing cattle receiving RumenGlas having a 19% increase in daily weight gain. A benefit to this feed additive is that it can be delivered in a pelleted concentrate formulation.
Reducing Nitrogen Loss from Tillage Ground - Catch crop update from the Agricultural Catchments Programme
All farming sectors have to reduce nitrogen (N) loss, in order to restore all water bodies to a good status by 2027. On free draining, nitrate leaching prone sites, research has shown that overwinter green cover can substantially reduce nitrate leaching to ground water from fallow crop land. The Agricultural Catchments Programme has been monitoring a tillage dominant river catchment in Castledockrell, Wexford since 2008 and has been focusing on winter green cover research. Ireland’s 5th Nitrates Action Programme (NAP), requires in all circumstances that 75-80% of harvested crops be shallow cultivated or sown with a crop within 14 days of harvest. The earlier the green cover is established, the more N it can capture.
Carbon Stocks and Sequestration in Hedgerows by Dr. Lilian O'Sullivan, Teagasc Johnstown Castle
Hedgerows have important benefits in agricultural landscapes. Along with acting as field boundaries, hedgerows provide animals with shelter, can support flood control, and are widely known for their importance for biodiversity. Increasingly though, farmers are interested in the carbon stock and sequestration potential of hedgerows and to see hedgerows accounted for in national inventories for greenhouse gases.
The Sustainability Digital Platform is being created to facilitate robust calculations of the environmental impact of a farming system. The Sustainability Digital Platform is an industry wide collaboration between Teagasc, ICBF, and Bord Bia. Farm data residing in existing databases, including those in ICBF and Bord Bia, will be collated to maximise the automation potential of the assessment process and improve accuracy of results to support decisions and transparency. The platform will be co-designed with advisors and farmers to ensure that it is user friendly, interactive, and informative.
The calculations used within this platform are based on significant research by Teagasc on specific models for calculating greenhouse gas and ammonia emissions over recent years and that are now adopted across the sector. The first phase is to develop a decision support tool to support farmers and advisors on recommended management practices that can improve a given farm’s performance. This phase is focused on beef and dairy systems, however the overall objective is to cater for a wide range of farming systems in Ireland.
The Sustainability Digital Platform will be piloted on Teagasc Signpost Programme farms before being deployed to all commercial farms. This platform will be used to establish the baseline performance of an individual farm in relation to greenhouse gas and ammonia emissions. The decision support tool will be used by advisors and farmers to determine the impact of key recommended practices to reduce emissions, including actions such as using protected urea and reducing chemical N usage (and in time, carbon sequestration potential on farms),which in turn will contribute to a farm specific action plan.
This infrastructure will ensure that each farm will be provided with results that are based on the same calculations, ensuring consistency in the figures. The Sustainability Digital Platform will ensure that each farmer “knows their number and can make a plan” to reduce the environmental impact of their farming system.
There are a number of measures sheep farmers can take to reduce GHG emissions; including optimising soil fertility, improving grassland management, increasing flock productivity, reducing days to slaughter and incorporating white clover into grazing swards. Research at Teagasc is looking into the effects of animal production on methane output with the aim to improve overall farm efficiency. Currently, the average GHG intensity of a lowland sheep farm is 10.6 kg CO2eq/kg live weight, with methane making up 66% of this. Portable accumulation chambers are being used to measure methane from sheep with over 10,500 records of methane output collected to date. Methane output is a heritable trait (i.e. the trait is under genetic control and can be passed from one generation to the next). Therefore, work is underway to develop a breeding sub-index for methane output in conjunction with Sheep Ireland. To date, research carried out at Teagasc shows the potential for breeding a more sustainable animal with animals ranked as 5 star on the Sheep Ireland €uro-star index producing 7% less GHG per unit of output (i.e. carcass weight). From a sward perspective, when the methane output of animals grazing swards incorporating white clover, red clover or plantain was investigated they ranked on average 12% lower than those grazing perennial ryegrass only swards.
The first large scale characterisation of methane emissions in Irish beef cattle conclusively shows that some beef cattle can produce up to 30% less methane emissions, on average, for the same level of productivity
There is an on-going research programme into slurry amendments at storage and landspreading phases in order to reduce environmental losses from these sources. Initially, the programme focused on water quality, in particular incidental nutrient (in the form of phosphorus) losses following slurry application to grassland (Brennan et al., 2011a; Brennan et al., 2011b; Fenton et al., 2011; Brennan et al., 2012, Brennan et al., 2014).
However, in recent years the focus shifted towards gaseous emissions, in particular ammonia, where manure management (housing, storage, landspreading) is responsible for nearly 80% of all emissions (EPA, 2020). Slurry amendments can be broadly divided into three categories: (I) chemical acidifiers reducing slurry pH, (II) physical / chemical adsorbents and (III) biological / microbial inoculants. Internationally, chemical acidifiers have been most extensively studied to date.
Our own work has already covered storage and landspreading experiments, where a selection of chemical acidifiers, alternative acidifiers (in the form of farm wastes and food production by products) and commercial products have been assessed (Table 1). In general, chemical acidifiers remain the most reliable options to reduce ammonia emissions, however possible negative impacts on nitrous oxide need further investigation. Alternative acidifiers proved inconsistent in their efficacy to reduce emissions, with the exception of silage effluent. Most waste products acting as alternative acidifiers introduced an additional source of labile carbon into the slurry, which often led to increased emissions of methane and carbon dioxide. Regarding products commercially available on the market, four have been used in incubation trials with little success. Three out of four commercial amendments, denoted Commercial A through to C, use bacterial inoculants as their active ingredients while the fourth product uses low dosage of chemical acidifying salts (Table 2).
Abating Ammonia in Agriculture
Currently, a large RSF project Abating Ammonia in Agriculture (Triple A) is focusing on quantifying ammonia emissions and abatement potential of various additives during slurry storage and landspreading, also in combination with low emission slurry spreading techniques. The project will investigate the impact of slurry amendments not only on ammonia, but also GHGs, agronomy and soil health. Concurrently, an SEAI funded project is studying efficacy of additional slurry amendments containing halide salts.
Table 1. Range of slurry amendments and their associated impact on gaseous emissions of ammonia, methane and nitrous oxide during storage and at land application, as quantified by the recent research carried out at Johnstown Castle.
Table 2. Active ingredients listed by the commercial slurry amendments.
Contributed by: Dominika Krol
Nitrogen fertiliser application represents the largest anthropogenic source of nitrous oxide (N2O) emissions, and the magnitude of these emissions is dependent on the type of fertilisers applied in the agroecosystems.
The purpose of this study was to evaluate the effect of fertilisers with contrasting NO3-to NH4+ ratios on N2O emission in temperate agricultural grassland.
These results are indicative of lower N2O losses associated with ammonium-based compound fertilisers due to the reduction in the soil nitrate pool. Read the research paper here Ammonium-Based Compound Fertilisers Mitigate Nitrous Oxide Emissions in Temperate Grassland (PDF)
Methane is a greenhouse gas that is predominately produced by ruminants such as cattle and sheep. As this gas contributes 59.3% to total agricultural greenhouse gases in Ireland, according to the 2021 Irish national greenhouse gas inventory report, it is important that it is measured in a pasture based system in order to ensure that appropriate methane measurements are included in the national inventory as well as identifying appropriate methane reduction solutions. Currently at Teagasc Moorepark there are 4 GreenFeed machines that are being used to measure methane emissions on over 150 dairy cattle while animals graze.
The GreenFeed system is essentially a feed bin on a trailer that also has the capability to measure methane, hydrogen and CO2. Small amounts of concentrate (30grams) is dispensed to the cow every 25 seconds while her head is inside the feed bin. Ideally a cow needs to have her head in the feed bin for at least 2 minutes, therefore the concentrate drops are spread out over a 2 minute period to entice the cow to stay at the machine. Each cow is electronically identified and her breath is sampled continuously while at the machine. A sub sample of the air exhaled by the cow is passed through various sensors while the cow is eating. . This information is then fed to a central database in the US via the mobile network where various algorithms are used to generate useful information from the data.
Current studies in progress include the development of a methane profile across the year, evaluation of grass quality, evaluation of feeding strategies, evaluation of animal breeds etc., have on methane production in dairy cattle in Ireland’s pasture based system.
Results from a recent Teagasc study indicate that average GHG emission intensity per kg of milk produced decreased by 13 % between 2000 and 2017. This means that dairy farmers are now producing each kg of milk with considerably fewer emissions than 20 years ago.
They also found that, on average, absolute GHG emissions have increased by 86 % per farm over the same period. While this increase in absolute GHG emissions per farm is significant, average milk output per farm has increased by much more (123 %).
Read more here Quotas and emissions (PDF)
A new scientific paper from Teagasc has shown that getting soil pH right through a liming programme can significantly reduce emissions of nitrous oxide (N2O), a potent greenhouse gas. The paper from researchers at the Teagasc Environment, Soils and Land-Use Department in Johnstown Castle, County Wexford has just been published in the scientific journal, Agriculture, Ecosystems and Environment (AGEE).
It concludes that increasing soil pH reduces fertiliser derived N2O emissions in intensively managed temperate grassland.
Head of the Teagasc Environment Research Department, Dr Karl Richards said: “The paper shows that there are reduced N2O emissions from fertiliser applied to higher pH soils, where the pH is in the recommended agronomic range. Farmers that can improve soil pH for agronomic benefits, can also reduce N2O emissions. This represents a win-win for the farmer and the environment.”
Soil pH is generally considered a master variable, controlling a wide range of physical, chemical and biological properties, including a significant effect on microbial processes responsible for production and consumption of N2O. Senior Research officer at Johnstown Castle, Dr David Wall stated that “using an existing long-term intensive grassland liming and P trial, this research investigated the effect of longer-term lime and P management and their interaction on N2O emissions and grassland productivity.
Postdoc Researcher with Teagasc, Ognjen (Oggy) Zurovec outlined the main findings: “We found that a long-term increase in soil pH as a result of liming significantly decreased N2O emissions over 12-month measurement period. In addition, keeping the soil pH and P at the optimum level has the potential to further reduce N2O emissions due to higher grass N uptake through increased yields. This means that the application of good farming practices has considerable N2O mitigation potential in temperate grasslands.”
The results showed that applying 5 tonnes of lime per hectare every 3-4 years increased soil pH from 5.1 to 6.9 and reduced N2O emissions by 39%. The study estimated that the increase in soil pH of grasslands in Ireland over the last 12 years potentially reduced national N2O emissions by 95,000 T CO2-eq yr−1, with potential for a further reduction by up to 254,000 T CO2-eq yr−1 if all the remaining acidic soils are brought up to optimal pH.
The paper can be viewed at https://www.sciencedirect.com/science/article/pii/S0167880921000232
A recently published study with dairy cows from Teagasc and UCD demonstrated that high EBI (€181) cows had 10% lower GHG emissions per kilogram of fat- and protein-corrected milk across a range of feeding system, compared to cows with a national average for EBI of €82. This paper highlights that using high EBI genetics will considerably reduce GHG emissions intensity across a range of pasture-based feeding scenarios, while contributing toward a small but favorable effect on N efficiency. The full paper is available in the Journal of Dairy Science