SSM-Wheat: a simulation model for wheat development, growth and yield

A robust crop model can assist in genetic improvement and cultural management of the crop. The objectives of this study were to describe a wheat (Triticum aestivum L.) model and to report results of its evaluation. The model simulates phenological development, leaf development and senescence, crop mass production and partitioning, plant nitrogen balance, yield formation and soil water and nitrogen balances. The model includes responses of crop processes to environmental factors of solar radiation, temperature and nitrogen and water availability. Parameters are inputted in describing physiological processes so that these can be varied to define genotypic differences. The model uses a daily time step and readily available weather and soil information. The model was tested using independent data and indicated an acceptable performance for important crop attributes as compared to observed results including days to anthesis (CV=4.5%; r=0.98) and maturity (CV=5.6%; r=0.96), crop LAI (CV=11.8%; r=0.80) and dry mass at anthesis (CV=9.3%; r=0.72) and total crop mass (CV=9.5%; r=0.82) at maturity and grain yield (CV=8.4%; r=0.89). It was concluded that the model can be used in simulation studies of wheat yield and its limitations in response to environmental conditions, management inputs and genetic factors.