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The described model is not intended to be an all-encompassing model, as others have attempted (50). The regression equations are not intended to be viewed as stimulus response situations. The flow chart for this model (Fig. 8) is simple and readily adaptable compared to SOYMOD (50) or SIMED (35). Changes in the regression coefficients, or in the regression equations, can describe different soybean varieties, different locations, or different years (Figs. 9, 10). This
flexibility is desirable in the basic framework of a model.
The time reserved for seedling emergence can be easily changed to more or less than seven days. This parameter would be location dependent. The seven day's for seedling emergence for northern Florida climatic conditions was adequate. The model could be refined to have the time required for seedling emergence linked to soil temperature and moisture or planting date. This refinement would be better than setting the time as a fixed value. Plant dry weight was not permitted to be
negative, as a negative measurement of dry weight is biologically meaningless. The regression equations were continuous with respect to the time variable. This, along with the equations not intending to describe a biologic phenomenon but to explain a phenomenon, can lead to negative values. Time was continuous in the