EVALUATION OF A PHENOMENOLOGICAL MODEL OF COASTAL BERMUDAGRASS PRODUCTION

A phenomenological simulation model of Coastal bermudagrass was previously developed. In this analysis data from four independent field studies were used to evaluate the model. Yield distributions over time plotted as straight lines on probability paper. Total yield showed a linear correlation with harvest interval. The model predicted both responses. Regression equations were used to relate each of the four model parameters to nitrogen level. Exponential dependence of mean time (T) and time spread (a) upon nitrogen was demonstrated. Dependence of the first order growth parameter (A) upon nitrogen followed the logistic function, while the curvature parameter (C) was described by the ratio of two logistic functions. The model relates dry matter yield to applied nitrogen and harvest interval. It is useful in evaluation of management alternatives for forage production. An example application is included.