A methodology and an optimization tool to calibrate phenology of short-day species included in the APSIM PLANT model: Application to soybean

We developed a methodology and an optimization tool that simplifies calibration of the APSIM PLANT multi parameter input phenology module. The methodology and the tool were successfully applied to estimate phenological parameters for 40 soybean cultivars covering maturity groups from 00 to 6. Our approach utilized information on flowering, physiological maturity and soybean maturity group, and provided a complete set of phenological parameters for APSIM that accounted also for temperature × photoperiod interactions throughout the crop cycle. The model predicted flowering (root mean square error, RMSE = 3.1 d) and physiological maturity (RMSE = 5.5 d) very well in a range of environments across the USA (33-46°N latitude, n = 280). The relative absolute error was below 3% in all cases indicating the robustness of our approach. The APSIM PLANT phenology module is generic, thus our approach can be applied to all the short-day species included in the modelling platform.