Tillage emissions stable
Despite profitability and weather related challenges, greenhouse gas (GHG) emissions from Irish tillage farms remained stable over 2023, the recently released Teagasc National Farm Survey (NFS) Sustainability Report 2023 has indicated.
Presented on both a yearly and three-year rolling average basis, the NFS report points to tillage GHG emissions of 1.9t CO2-e per hectare in 2023, or 2.0t CO2-e per hectare in the period encompassing 2021 to 2023. Additionally, emissions per hectare tended to be lower for the better performing farms in economic terms in 2023.
The report highlights that the average tillage farm produced 145.8 tonnes CO2-e of agricultural GHG emissions in 2023. However, only 26.4% of GHG emissions on these farms were generated from crop production. Despite being specialised in crop production, 57.4% of tillage farm emissions were from cattle present on these farms, with a further 16.2% from sheep.
Energy based GHG emissions were also quantified as part of the report, showing that specialised tillage farms, on average, produced 0.21 tonnes of energy based GHG emissions per hectare in 2023, and higher emissions per hectare were associated with higher economic performance.
Again, livestock enterprises come into consideration when the ammonia (NH3) emissions from tillage farms were collated. Tillage farms on average had NH3 emissions of 0.87 tonnes in 2023. However, even though the main farm output on such farms is crop related, the bulk of NH3 emissions are associated with cattle rearing, at 47.8%. Of the remaining emissions, 47.2% were associated with tillage production and 5% with a sheep enterprise, the Teagasc National Farm Survey (NFS) Sustainability Report 2023 has shown.
On a per hectare basis, this resulted in the average specialist tillage farm emitting 10.7kg of NH3 per hectare in 2023. In terms of the variation witnessed between farms, emissions per hectare were highest for the top and middle farms in terms of economic performance.
N and P
As part of the NFS recording process, data on the nitrogen balance and nitrogen use efficiency is also gathered.
The former is used as an indicator of the potential magnitude of nitrogen surplus, which reflects the risk of nutrient losses to water bodies all other things being equal. It is calculated on the basis of N inputs less N outputs on a per hectare basis at the farm gate level. For tillage farms in 2023, the average N surplus was 45.8kg per hectare, but there was a large range with farms of lower economic performance having higher N surpluses per hectare on average.
Nitrogen use efficiency is an indicator used to highlight the proportion of N retained in the farm system (N outputs / N inputs). This is a generic measure allowing comparison across disparate farm types at the farm gate level. Across all tillage farms recorded through the NFS, the average N use efficiency (NUE) was 65.7% in 2023.
Phosphorus balance per hectare farmed is used as an indicator of the potential magnitude of phosphorus surplus which may result in nutrient losses to water bodies all other things being equal. It is calculated on the basis of P inputs less P outputs on a per hectare basis at farm level. The average P balance across all tillage farms was 2.1kg per hectare. However, there was again a large range of results with better farms, in economic terms, tending to have slightly lower P balances.
Used to highlight the proportion of P retained in the farm system, P use efficiency (PUE) averaged 93.8% across all tillage farms, with PUE tending to be higher on top performing farms in terms of economic returns, compared to the middle and bottom cohorts.
More information
The above was adapted for use on Teagasc Daily from the Teagasc National Farm Survey Sustainability Report 2023, which was authored by Cathal Buckley and Trevor Donnellan from the Teagasc Agricultural Economics and Farm Surveys Department.
Also read: Sustainability performance of Irish farms in 2023 revealed