Making effective, flexible and environmentally responsible fertilizer recommendations
Dave Mengel, Department of Agronomy, Kansas State University, Manhattan, Kansas 66502 E-mail: dmengel@ksu.edu

Making fertilizer recommendations for nutrients which accumulate in soil, such as P and K, is a more complicated process than it was two or three decades ago. Today, in addition to ensuring that the recommendations are effective and produce high yields, one also has to consider the volatility of commodity and fertilizer prices, and the economics of fertilization, plus the impact of your recommendations on the environment, especially in the case of P, water quality. Thus recommendations today should discuss more than just the rate of nutrient to apply, but also source, timing and method of application. The concept of the 4 R’s; Right Rate, Right Source, Right Time and Right Place is extremely important when balancing yield, economics and environment.

This presentation will discuss the basic concepts of developing fertilizer recommendations, including: soil test correlation and calibration; the two primary systems used to make fertilizer recommendations, Nutrient Sufficiency and Build and Maintain; and how fertilizer placement can impact both yield and water quality.