Lucie and Roger discuss the intricacies and applications of crop simulation models in agricultural research. Roger explains the historical development of these models since the 1980s and provides a detailed explanation of how crop simulation models work, such as the DSAT and APSIM systems, which are used extensively in the United States and Australia. The discussion underscores the models’ value in complementing traditional field experiments, especially in understanding long-term agricultural dynamics. They also touch on the challenges of implementing these models in Africa due to climatic data availability.