Model analysis of forage response to split applications of nitrogen. I. Plant tops

The extended logistic model was developed to relate crop production (dry. matter and plant nutrient uptake) to applied nutrient. In this article the model is used to analyze the effect of split applications of applied nitrogen to Pensacola bahiagrass (Paspalum notatum Flugge) on a poorly drained soil. The model describes the response curves for seasonal dry matter yield (Y), seasonal plant N uptake (N-u), and plant N concentration (N-c) to applied nitrogen (N), as well as the phase relations (Y and N-c vs. N-u). Detailed analysis showed no clear benefit for split vs. single applications. This agrees with findings with other crops on different soils.