ABSTRACT
This chapter describes approaches for mathematical simulation of plant growth and yield processes, following the example of the CROPGRO model. It focuses on crop development, carbon balance, and plant internal nitrogen balance aspects but illustrates how crop C and N balances are coupled to soil N and soil water balances. The goal of most crop growth simulation models is to predict the physical processes of plant carbon balance, soil–plant–water balance, soil–plant–nitrogen balance, and, in many cases, energy balance, in response to soil and aerial environment, crop management, and crop/genetic characteristics. The CROPGRO model uses various more complex equations for predicting photosynthesis, maintenance respiration, and conversion efficiency; nevertheless, the coupling points to these state variable equations and the daily integration loop remain unchanged. The CROPGRO model has two options for photosynthesis calculations: daily canopy photosynthesis or hourly leaf-level photosynthesis with hedgerow light interception.
