At the recent Signpost general assembly, Teagasc presented an update on the performance of the Signpost demonstration farmers in reducing greenhouse gas emissions.

This article sets out the uptake of recommended climate mitigation practices for the farms participating in the programme and describes changes over the first 24-month period (2021 and 2022).

Protected urea

  • The Signpost dairy farmers are using protected urea as a source of more than half of their fertiliser N, compared to 15% for the typical dairy farmer.
  • Cattle Signpost farmers spread 38% of their total chemical N as protected urea, compared to just 4% for cattle farmers nationally.
  • On sheep farms, protected urea made up 19% of the chemical N applied. The national average is 2%.
  • While traditionally tillage farmers have used CAN as their primary N source, Signpost tillage farmers are beginning to see the benefits of protected urea and 26% of chemical N on these farms was applied as protected urea in 2022.

    One tillage farmer has shifted from using 0% protected urea in 2021 to 74% of chemical N applied as protected urea in 2022.

    While the Signpost Farmers are using proportionally more protected urea than other farmers, there is still scope to significantly increase its usage on all Signpost farms.

    • Protected urea on the left and cut sward on the right.

    Liming

    The Signpost Farms were extensively soil sampled in late 2021 and early 2022, and the farmers have used the results to target lime applications during both 2021 and 2022.

    There has been a significant increase in lime use across all farm types over the two years. The Signpost dairy and cattle farmers applied, on average, 0.8t and 0.6t lime per hectare farmed, respectively, for each of the two years, 2021 and 2022. This represents almost twice what the typical dairy and beef farmer applied during the same period.

    Lime use on sheep farms increased by 47% in 2022.

    Lime.

    In the year that lime is applied, it results in an increase in GHG emissions as carbon dioxide is emitted from the calcium carbonate or magnesium carbonate applied. However, applying lime will release up to 80 kg N, allowing farmers to reduce total chemical N use in the following years.

    So, the Signpost farmers are taking steps to reduce their reliance on fertiliser N.

    Low emissions slurry spreading (LESS)

    All Signpost farmers got their slurry analysed in either 2021 or 2022. This has allowed Signpost farmers to make better use of their slurry with more slurry applied in the spring and applied with LESS.

    Low emissions slurry spreading equipment.

  • Dairy farmers applied all of their slurry with LESS.
  • 79% of the slurry on Signpost cattle farms was applied using LESS.
  • Thirty-three per cent of the slurry was applied by LESS on sheep farms.
  • There has been an increased emphasis on the use of organic manures on tillage farms (replacing artificial fertiliser).

    • Clover

    On dairy farms, almost half (46%) of the grazing block has clover incorporated, achieved through a combination of direct reseeding and over-sowing. This sets these farmers up for further reductions in chemical N use.

    On cattle farms, 85% of the farm had some level of clover, although half of this was scored as having low clover levels.

    There is considerable scope on all livestock farms to increase the proportion of clover and multispecies in the swards, further reducing reliance on chemical N.

    Twelve per cent of the land base on Signpost tillage farms was dedicated to legumes in 2022 and 17% of the total land farmed was sown to catch crops.

    Reduced chemical N use

    All Signpost farmers have started the transition to a lower dependence on artificial fertiliser nitrogen.

    In 2022, there was a reduction in fertiliser N usage by 17%, 14%, 21% and 12% for the Signpost dairy, cattle, sheep and tillage farmers, respectively.

    The reduction in chemical N use has been achieved through a combination of technologies, including liming, better use of slurry and incorporation of clover/multispecies swards into grazing blocks.

    Tillage farmers are making better use of legumes and organic manures to reduce reliance on chemical N.

    Both the reduced fertiliser N use and the increased proportion of protected urea recorded in 2022 was counterbalanced to some extent by an increase in lime usage in terms of overall farm GHG emissions.

    However, lime application is an investment and a once off GHG cost that will pay dividends in lower fertiliser use and lower GHG emissions in future years.

    Next steps on Signpost farms

  • All Signpost farms have received individual sustainability reports. These will be used to identify areas for further improvement.
  • We will continue to focus on MACC measures, especially reduced fertiliser N use, improved nutrient recycling, clover management and switching to protected urea.
  • We will also continue to work with our Signpost farmers on the newer MACC measures, including age at finishing, sexed semen usage and DBI/CBV.
  • Finally, we are exploring how we can demonstrate the climate mitigation technologies of feed and slurry additives on these farms; but that is a little while away just yet.

    • These Signpost farmers are well ahead of the national average in terms of their adoption of key climate mitigation technologies.

    Teagasc will continue to work with the Signpost demonstration farmers to support them in the adoption of the available technologies.

    The big challenge, and the purpose of the programme, is to get other farmers to follow them, and move the national average towards the levels on the Signpost farms.

    These results show that farmers can have confidence in the technologies, as their use on the Signpost farms has not impacted negatively on profitability or productivity.