Crop sequence effects on energy efficiency and land demand in a long-term fertilisation trial

The effect of crop sequences (CR – continuous winter rye; CropR – three-field crop rotation of winter rye-spring barley-bare fallow) and fertilisation systems (unfertilised control, mineral fertiliser (NPK), farmyard manure (FYM)) on crop yield, energy efficiency indicators and land demand were analysed in a long-term experiment under Pannonian climate conditions. Due to lower fuel consumption in the bare fallow, the total fuel consumption for CropR was 27% lower than in CR. It was for NPK and FYM fertilisation by 29% and 42% higher than in the control. Although the energy output was lower in CropR than CR, the energy use efficiency for grain production increased by 35% and for above-ground biomass production by 20%. Overall crop sequences, the NPK treatment had higher crop yields, energy outputs and net-energy output with a lower energy use efficiency than the unfertilised control. CropR increased the land demand just by 20% in comparison to CR, although one-third of the land was not used for crop production. The land demand could be decreased with fertilisation by 50% (NPK) or 48% (FYM). A bare fallow year in the crop rotation decreased the crop yield, energy input and increased the energy use efficiency and land demand.