Guidelines for Corn Yieldbased approach to N recommendations has been questioned Poor relationship between recommendations and EONR from N rate response trials Uncertainly about how yield goals should be determined ID: 760176
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Slide1
Concepts and Rationale for Regional Nitrogen Rate Guidelines for Corn
Slide2Yield-based approach to N recommendations has been questioned
Poor relationship between recommendations and EONR from N rate response trials
Uncertainly about how yield goals should be determined
Assumption that NUE is constant across sites
anyears
Use of inadequate or inappropriate adjustments for
nonfertilizer
N sources
Slide3Data showed that optimum N rates increased over time at one site and decreased at the other site
Results provide no clear indication of a change in N rates over time
Reasons for similar or decreasing optimum N rates where yields have increased substantially include more efficient utilization of available N by the crop and increased soil N supplying capability