ABSTRACT
This chapter shows the utility of computer simulation models in crop-pesticide interaction studies, describes models and the modeling process, and demonstrates results from a specific model. The most crucial part of the modeling process is the initial phase, which consists of defining the scientific problem and determining project objectives. An important factor in model implementation is complexity balance among components. Balance problems may arise during the formulation stage, but are most likely to occur during implementation. Verification is the step in which computer code is tested for accuracy of representation of the model mathematical concepts and relationships. Validation is the second phase of model testing. Modelers produce documentation throughout the development steps. The Opus model was chosen to demonstrate a simulation model of pesticide fate because of the authors' familiarity with it. Opus has an assortment of output options. The chapter presents a case study using the Opus model.
