Operationalising eco-efficiency in agriculture: the example of specialised dairy farms in Flanders
Eco-efficiencies of a representative set of Flemish dairy farms were determined for the years 19891990 and 20002001. Eco-efficiency was measured as a combination of nitrogen (N) use efficiency and energy use efficiency, where N use efficiency (l milk kg-1 N surplus) is the ratio between the amount of produced milk and the farm-gate N surplus (= N input − N output). Energy use efficiency (l milk 100 MJ-1) is the ratio between the amount of produced milk and the total (direct + indirect) energy input. Between 19891990 and 20002001, average N use efficiency increased from 27 to 40 l milk kg-1 N surplus and average energy use efficiency increased from 22 to 27 l milk 100 MJ-1, indicating an overall increase of eco-efficiency of the Flemish dairy farms during those periods. The farms with the highest eco-efficiencies were characterised by a higher milk production, a lower N surplus, a lower energy input and a higher gross value-added. The latter shows that on the studied farms, eco-efficiency went hand in hand with better economic results.
Keywords: dairy farming, eco-efficiency, energy efficiency, Flanders, nitrogen use efficiency, Belgium, industrial ecology, agriculture, milk production