In numerous articles, the extended logistic model has been used to describe response of annual and perennial crops to applied nutrients [such as nitrogen (N), phosphorus, and potassium]. The model accounts for coupling between dry matter and plant nutrient accumulation by way of phase relationships. Factors such as water availability and harvest interval (for perennials) can be easily incorporated. The model is well behaved and is simple to use for estimation purposes. In this article, response of a bunchgrass to applied nitrogen and rainfall is discussed. Field studies in Florida lead to similar parameter values as those in Texas. Linkage of lower and upper limits on plant N concentration is explained.