APSIM’s origins and the forces shaping its first 30 years of evolution: A review and reflections

Simulation models have co-evolved with agricultural research methods over the last 60 years and they are now a widely accepted and deployed component of agricultural research and development. Modelling supports research in a very diverse range of disciplines and situations, but nowhere more so than in farming systems research. The complex interactions in space and time in the face of climate variability and change that characterise contemporary farming systems research create a situation in which farming systems models are vital tools in interpreting and generalising research results. This review examines the evolution of one of the most widely used farming systems modelling platforms, the Agricultural Production Systems Simulator (APSIM). The review sets the scene for APSIM development with an account of research approaches in agronomy during the 1960s and 1970s. The early innovations in crop and soil modelling in the 1980s are covered briefly and a more explicit history of APSIM development is reported from the 1990s. Reports of APSIM use and impact are reviewed over the 2000s and 2010s. The review concludes with reflections on the forces that have shaped and enabled this more than 30-year history of APSIM development and use, together with a look forward to future challenges. Recent developments in proximal and remote sensing together with advances in the power of empirical models arising from machine learning are not seen as threats but more so opportunities for sound bio-physical models to be deployed with greater effect.