Designing sustainable crop rotations using Life Cycle Assessment of crop combinations

The introduction of grain legumes in crop rotations offers the potential to reduce the environmental impact of European agriculture. The main advantage is the independence of nitrogen fertilisers due to symbiotic N2 fixation and hence the reduced use of fossil energy and lower global warming potential at the crop rotation level. As the assessment of a large number of crop rotations with Life Cycle Assessment (LCA) is very time consuming we applied a new crop combination approach i.e. for each crop a LCA is calculated for each possible preceding crop and in a second step the rotations are composed using these crop combinations. The procedure enables a fast assessment of several rotations as the production inventories of a main crop have to be only slightly adjusted for several preceding crops. In this paper the authors show preliminary results for several rotations and the associated crop combinations. These results indicate that the introduction of a spring pea in a standard rotation (oilseed rape, winter wheat, winter barley) might reduce the global warming potential (GWP) by around 6%. If the fertilisation of cereals and oilseed rape is also reduced the overall GWP decreases by 11%. For nutrient enrichment the reduction potential is around 6% and respectively 13% for the combined approach.