Research by Teagasc found that it was possible to substantially lower the greenhouse gas emissions (GHG) of milk by cutting chemical fertiliser use and other methods, while still maintaining net margin.
James Humphreys from Teagasc’s Solohead farm in Co Tipperary presented the findings of the three-year study at the Catchment Science 2023 conference last week.
The objective was to investigate the economic impact of grass-based dairy systems incorporating various practices for lowering GHG emissions.
These practices included using clover, switching to protected urea, using low emission slurry spreading (LESS) and high-EBI cows.
The research team assessed three different systems over three years.
The control system received 275kg/ha of bagged nitrogen, applied as urea and calcium ammonium nitrate, and slurry was applied using a splash plate.
The second (WC90) system was a clover-based system receiving 90kg/ha of nitrogen, applied as NBPT-urea and slurry was applied using LESS methods. The third (WC0) system did not receive any bagged nitrogen and slurry was applied using LESS.
The average EBI of cows on the control and WC90 systems was €147 and cows on the WC0 system averaged €185.
The WC0 system had substantially lower GHG emissions (0.69kg CO2 eq per kg of fat and protein corrected milk) compared to 0.90kg for the control and 0.78kg for the WC90 system. Crucially, the WCO system maintained a similar net margin to the other systems, despite having no chemical fertiliser applied.