Fertiliser use changes, impacts and key recommendations
Mark Plunkett and Dr. Siobhán Kavanagh, Teagasc Signpost Programme, take a closer look at how fertiliser use changed on farms over 2024, examine the possible environmental impacts and share a number of key recommendations for the year ahead.
The National Fertiliser Use Report 2024, stemming from Department of Agriculture, Food and the Marine Fertiliser Sales from 1st October 2023 to 30th September 2024, highlights significant trends and developments in fertiliser usage in Ireland, reflecting shifts influenced by economic, environmental and climatic factors.
Key trends
The report illustrates key trends in relation to nitrogen (N), phosphorus (P) and potassium (K) fertiliser use, while lime application data is also encompassed.
Nitrogen (N) use
Total chemical N usage increased by 10.6% to 310,411 tonnes in 2024, compared to 2023. However, this remains within the Climate Action Plan target of 330,000 tonnes for 2025.
Positively and reflecting the progress toward the 2030 target of 90-100% uptake on grasslands, protected urea use rose significantly, comprising 27% of straight N fertilisers. Additionally, and further emphasising a shift toward reduced ammonia emissions, combined urea and protected urea accounted for 50% of the straight N market.
Phosphorus (P) and potassium (K) use
Continuing a concerning trend with a cumulative reduction of 38% since 2021 (for P), potentially undermining soil fertility and nitrogen efficiency, chemical P usage fell by 6.6% in 2024. However, K usage rebounded by 7.45% to 88,058 tonnes in 2024, indicating a positive but insufficient recovery to meet national soil fertility needs.
Lime applications
Hindered in some ways by unfavourable weather, lime usage - vital for correcting soil pH and reducing dependence on chemical N - is estimated to reach 800,000–1,000,000 tonnes in 2024.
Environmental impacts and recommendations
On account of the above changes, it is estimated that fertiliser-related greenhouse gas (GHG) emissions increased slightly (0.7%) in 2024 due to rising N usage. However, fertiliser-related emissions remain 30% below 2018 levels, driven by reduced overall N use and a transition toward more sustainable fertilisers like protected urea.
To limit a future increase in fertiliser related GHG emissions, farmers are urged to prioritise soil fertility through targeted P and K applications, enhanced fertiliser planning, and soil testing. The continued decline in the use of P is a real concern for soil fertility and N use efficiency on farm, while the increase in K application is positive.
Additionally, a transition from high-nitrate compounds (24’s/ 27’s) to ammonium-based compounds (10’s / 18’s) is recommended to curb GHG emissions, and a greater adoption of lime application and clover / multispecies swards is encouraged to sustain reduced N levels and enhance nutrient efficiency.