Independence of yield potential and crop nitrogen

Authors: William R Raun John B Solie Marvin L Stone

Publish Date: 2010/10/02

Volume: 12, Issue: 4, Pages: 508-518

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Abstract

Crop yield level and nitrogen N responsiveness influence the demand for fertilizer If they were found to be unrelated this would justify using a combination of both for determining fertilizer N requirements Failure to understand the independence of crop response to N and yield level has led to confusion as to what theory is appropriate for making N fertilizer rate recommendations The sufficiency approach applies a fixed rate of N at a computed sufficiency level regardless of yield potential Alternatively midseason optical sensor estimates of yield potential and crop response to additional N provide a physiological basis to estimate N removal and a biologically based N application rate This study investigated the relationship between grain yield and response to N in longterm wheat and corn experiments No relationship between response to N and grain yield was found There was also no relationship between yield and year at two of three sites Finally there was no relationship between response to N and year at any site Because yield and response to N were consistently independent of one another and as both affect the demand for fertilizer N estimates of both should be combined to calculate realistic inseason N rates

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