The Signpost programme is a Teagasc-led initiative aimed at reducing greenhouse gas emissions (GHG) at farm level while also improving water quality and enhancing biodiversity on Irish farms.
Siobhán Kavanagh, Tom O’Dwyer, Seamus Kearney, Shane O’Hanlon, Eoin Downing and Loreto Ferguson in Teagasc are heading up the programme and they will be supported by local advisers around the country to help implement the changes required on farms to lower GHG emissions.
There are currently 117 Signpost demonstration farms selected. These farms are made up of a number of conventional and organic beef, dairy, sheep and tillage farms, as well as some pig farms and agricultural colleges.
It is envisaged that these farms will be the “early adopters” of the technologies required to reduce GHG emissions. These farmers, along with their advisers, will provide the leadership in making the changes so that other farmers will have the confidence to make the necessary changes on their farms.
The messages from the programme will be delivered via a network of discussion groups, events and one-to-one consultations. Farmers will be able to track the progress of their local Signpost farm and see the challenges that they are encountering while trying to reduce their emissions.
Deep soil samples have been taken on Signpost farms to establish baseline soil carbon levels
Teagasc has also established the National Agricultural Soil Carbon Observatory to provide the knowledge required on soil carbon sequestration.
The Signpost farms will be an integral part of this observatory.
Deep soil samples have been taken on Signpost farms to establish baseline soil carbon levels, with this sampling is due to be repeated in a number of years’ time to monitor any changes.
The Teagasc Signpost programme team has identified a number of key areas that beef farms can work on to deliver a reduction in GHG emissions.
Improving animal breeding performance
Reduced age at slaughter
Finishing animals at a younger age results in reduced lifetime emissions through less methane produced from live animals and animal slurry.
The economic impact of increased weight gain is estimated at €0.21 per kilo of beef produced for an increase of 100g/head/day in lifetime performance. The impact of increased weight gain on GHG emissions is estimated at 2% per 100 g increase in lifetime average daily gain for beef cattle systems.
Sick animals result in reduced performance which will, in turn, mean an older finishing age and increased emissions. It’s important to have an animal health plan for a beef farm.
Increasing the grazing season length lowers GHG emissions. Grazed grass has higher digestibility than grass silage resulting in improved productivity and less energy lost as methane.
Also, the ensuing shorter housing period means less slurry stored and less slurry to be applied, resulting in less emissions.
It is estimated that for every 10-day increase in days at grass, profit increased by €25/cow or €1,000 in a 40-cow herd. The corresponding reduction in GHG emissions is 1.7%.
Nitrous oxide (N2O) is a GHG which has almost 300 times more global warming potential than carbon dioxide (CO2).
It is lost to the atmosphere from the breakdown of organic and chemical fertiliser.
The spreading of chemical fertilisers including calcium ammonium nitrate (CAN) emits high levels of N2O. Protected urea is designed to slow the rate at which urea is converted to ammonium, reducing N2O emissions.
Protected urea is 25% to 30% cheaper than CAN and grows similar grass yields. Protected urea has 71% lower nitrous oxide emissions than CAN.
Reducing chemical nitrogen use
In addition to switching to lower emitting forms of fertiliser, reducing total quantities of chemical N reduces N2O emissions.
A reduction in N fertiliser of 10 kg per ha will reduce farm GHG emissions by 1% and improve income by €10/ha.
Improving soil fertility and liming
Soil sampling and the implementation of a nutrient management plan are key to reducing chemical N fertiliser use. Spreading lime to increase soil pH has the potential to release up to 80kg N from the soil and yield a return of €6 to €10 for every €1 spent on lime.
Optimising the use of slurry
Slurry is a valuable source of fertiliser, particularly if it is applied at the right time of the year (spring), using the right equipment (low emission slurry spreading (LESS) equipment).
Spring application captures an extra three units N / 1,000 gals of slurry and using LESS contributes an additional three units N / 1,000 gals of slurry.
Spring application also reduces the storage period and the associated emissions. A 20% shift to spring application can reduce farm GHGs by 1.3% while a shift to trailing shoe can lead to a reduction of 0.9% in GHG emissions.
Incorporating clover into grassland reduces the demand for chemical nitrogen.
Therefore, if there is less chemical N fertiliser spread, there is less N2O being emitted into the air.
Clover has been shown to ‘fix’ the equivalent of 100 kg inorganic N/ha from the atmosphere.
On suckler farms, profitability increased by 14% for the grass/clover system when compared to a ‘conventional’ pasture system.