ENERGY USE AND ENERGY EFFICIENCY OF CORN PRODUCTION IN DIFFERENT FERTILIZATION STRATEGIES

Due to increasing energy prices, the efficient use of technical energy in cropping systems become more important. In long term trials (2007-2012) at two experimental sites ("Wagna" and "Wagendorf") in the Austrian province of South Styria, the direct energy use (fuel, heating oil, electricity) and indirect energy use (energy for the production of farm machinery, herbicide, fertilizer and seed) as well as energy efficiency in corn production were analysed. The influence of different mineral nitrogen fertilization rates (0, 90, 115, 145, 175, 210 kg N/ha as calcium ammonium nitrate) and a liquid pig manure treatment were compared. The calculated energy efficiency indicators (energy intensity, energy output/energy input-ratio, netto-energy output) showed, that the soil fertility had a big influence on energy efficiency. The energy efficiency indicators at the experimental site Wagendorf with very good soil conditions were better than at Wagna. Within the mineral nitrogen treatments in Wagna, the nitrogen fertilization rate of 90 and 115 kg N/ha reached the highest energy efficiency, whereas at Wagendorf it was at the 0 kg N/ha. Independently of the experimental site, the liquid pig manure treatment had the highest energy efficiency. The largest components of energy input in corn production with mineral fertilizer were the energy for drying (between 20.3 and 48.3 %) and energy for fertilizer production (between 20.7 and 37.2 %). For the mitigation of fossil energy input in corn production, a site specific nitrogen fertilization - at efficient with organic manure - and the application of regenerative energy carrier in corn drying are derived.