PARAMETERIZED MODEL OF GRAMINEOUS CROP GROWTH .1. LEAF-AREA AND DRY MASS SIMULATION

Parameterization is a technique used by modelers to approximate the response of a physical system using an empirical function. This technique has the advantages that it reduces the complexity of models and often simplifies their input requirements, making the models more easily usable for operational purposes. In this study, a relatively simple model of leaf area and dry mass growth for the gramineous crops was developed to demonstrate the use of parameterization. Results of model simulations for grain sorghum (Sorghum bicolor (L.) Moench], com (Zea mays L.), and spring wheat (Triticum aestivum L.) were in reasonable agreement with field observations. The effects of plant population, fertilization level, and water stress on crop growth were implicitly accounted for in the simulations through the appropriate assignment of parameter values in empirical functions controlling leaf area appearance and senescence.