From wheat to beet – challenges and potential solutions of modeling crop rotation systems in LCA

One of the remaining methodological challenges of agricultural LCAs is the inclusion of crop rotation effects. They are caused by changes in physical, chemical and biological properties of the agricultural land over time (e.g. soil structure, presence and availability of nutrients, phytosanitary conditions) and cannot be easily measured. LCA studies, focusing on only one vegetation period, have a limited ability to include those crop rotation effects, unless explicit modeling measures have been taken to include them. A summary on existing approaches is given and remaining gaps are identified. A new approach for the modeling of crop rotation effects is suggested. It includes the alignment of system boundaries with the whole crop rotation system, a systematic description of crop rotations, the inclusion of all inputs and all outputs and as a last step, allocation to the crop specific burdens using the agriculture-specific Cereal Unit.