Total farm greenhouse gas (GHG) emissions on the average dairy farm increased in 2020, largely due to an increase in the average herd size. However, GHG emissions per hectare on dairy farms remained relatively stable, as the average dairy farm area increased.
The Teagasc National Farm Survey 2020 Sustainability Report, which provides the latest available information on farm sustainability performance in Ireland, was published today.
The report is based on detailed analysis of data collected through the Teagasc National Farm Survey.
On the dairy side, the report revealed that the GHG emissions intensity of milk production improved.
Effectively, according to the report, this means that the average kilogramme of milk was produced with a lower carbon footprint.
However, this improvement in GHG intensity was offset by a higher volume of milk produced on the back of a larger average herd size.
So, farm level GHG emissions increased on dairy farms in 2020.
Delving a little deeper into the detail, the report found that, in 2020, the average dairy farm produced 510.7t of agricultural GHG emissions (in CO2 equivalent). It should be noted that these measures are based on the Intergovernmental Panel on Climate Change definition of agricultural emissions.
At 73%, most dairy farm emissions were from milk-based output.
A further 26.7% came from beef production on these farms – this would include emissions from cull cows and calf sales and transfers.
The remaining, less than 1%, were associated with sheep and arable production on dairy farms.
Emissions – a break down
CO2
The average dairy farm emitted 8.61t of CO2 equivalent (CO2e) per hectare. The better performing farms, in an economic sense, tended to operate at higher intensities and this is reflected in higher GHG/ha
When emissions allocated to dairy output are expressed per kilogramme of milk output, the average dairy farm emitted 0.81kg CO2e/kg of milk produced.
Farms with a better economic performance also tended to have the lowest emissions intensity per kg of milk produced.
Ammonia
The average dairy farm emitted 48kg of NH3/ha across the entire farm.
Economically better performing farms tend to operate at higher intensities and this is
reflected in higher emission of ammonia per hectare.
The average farm emitted 0.0044kg of NH3/kg of fat and protein corrected milk (FPCM) produced.
The top economic performing dairy farms produced milk at a lower NH3 GHG intensity compared to the middle and bottom cohorts.
Nitrogen
Nitrogen balance – excess of nitrogen inputs over outputs – averaged 172.6kg nitrogen surplus/ha across all dairy farms in 2020.
On average, dairy farms produced 75.3kg of FPCM/kg of surplus nitrogen.