Global food security, climate change and extreme events raise new challenges for modelling agricultural systems as they present challenges beyond the beyond the more traditional scope of single annual crops. These new challenges require: a much expanded range of primary crops that are usually more complex to model than grain crops; the inclusion of additional trophic levels such as ruminants and pests within the modelling system; inclusion of flow-on effects related to ecosystem services that feed back into the production system; greater understanding of the uncertainty associated with modelled outputs; improved understanding of the methods to scale up simulations to larger geographic or time scales that include proper consideration of the relationships between production enterprises; and software systems to support these new developments. This session aims to gather methodological, technical and application contributions that address these challenges.