Abstract
In long term trials (2007-2012) at two experimental sites in South Styria (Wagna and Wagendorf). the direct energy use (fuel, heating oil, electricity) and indirect energy use (machinery, herbicide, fertilizer and seed) as well as energy efficiency in grain maize production were analysed. The influence of different mineral nitrogen fertilization treatments (0, 90, 115, 145, 175, 210 kg N/ha as CAN) and a liquid pig manure treatment were compared. The calculated energy efficiency indicators (energy intensity, energy output/energy input ratio, net-energy output) are decisively influenced by the soil fertility and fertilization level. The highest energy efficiency was reached with the liquid pig manure. The energy for drying and for fertilizer production was between 20.3 and 48.3 %, which means 20.7 and 37.2% of the total energy input.