Model Analysis of Response of Pensacola Bahiagrass to Applied Nitrogen, Phosphorus, and Potassium. II. Seasonal P and K Uptake

Abstract

The extended multiple logistic model has been used to describe seasonal dry matter and plant nutrient uptake in response to combinations of applied nitrogen (N), phosphorus (P), and potassium (K) for bermudagrass (Cynodon dactylon L) and tall fescue (F. arundinacea Schreb.). In this article, the model is used to analyze data for bahiagrass (Paspalum notatum Flügge) in an N × P × K = 3 × 3 × 3 factorial experiment at Quincy, FL. A procedure is illustrated for standardizing the model over two of the nutrients in order to focus on response to the third. Estimates are made of applied N, P, and K required to reach 50% of maximum potential yield. Similar calculations are included to achieve 50% of potential maximum plant P and K uptake. The strong sensitivity of plant P and K to applied levels of P and K is described as well.