Assessment of GHG Emissions and Their Variability of Meat Production Systems in Wallonia Based on Grass and Maize

Within the framework of the Optenerges project, funded under the Interreg IV program, the greenhouse gas (GHG) emissions of 62 cattle farms representative of the main production systems in the Province of Luxembourg in Wallonia, Belgium were assessed. The main goal of this study was to give reference values for GHG emission intensity in meat production systems based on grass (G) and on grass and maize (G-M). A second goal was to analyze emission variability in order to identify potential mitigation options. On average, for every kg live weight the G systems emitted 18.2 CO2 eq.. and the G-M systems 19.2 CO2 eq.. The difference reflected differences in feed and mineral fertilizer purchases, in manure emissions and in mineral fertilizer application. There were large variations in GHG emissions both between and within the two systems, particularly the latter. This variability was not due to the division of the farms into G and G-M systems, indeed production system types did not allow explaining the variation. When carbon credits were included in the assessment, there was an emission reduction of 31% and 23% for the G and G-M systems, respectively, indicating an opportunity for the systems using grassland to increase their advantage.