USE OF YIELD GOALS FOR PROVIDING N RATE SUGGESTIONS: GENERAL CONCEPT

Paper give by Dr. Paul Fixen at the 2006 Northcentral Extension-Industry Soil Fertility Conference

Abstact:

Recent studies in the North Central region have shown a poor relationship between optimum yield of individual sites and optimum fertilizer N rate (Sawyer et al., 2006). The outcome has been the development of fertilizer recommendation approaches that do not consider site yield goal (Vanotti and Bundy, 1994a; Sawyer and Nafziger, 2005). This causes one to ponder how so many recommendation programs utilizing yield goal were developed in the first place and have continued in use for more than 40 years. It appears to be an appropriate time to review the general concept of use of yield goals in N recommendations. That will be the primary objective of this narrative with a secondary objective of relating the traditional concept to the recent studies suggesting a very limited role for yield goal in predicting N fertilizer need.