Corn Yields with Fall, Spring, and Sidedress Nitrogen1
- L. F. Welch,
- D. L. Mulvaney,
- M. G. Oldham,
- L. V. Boone and
- J. W. Pendleton2
Studies in central and northern Illinois at 4 locations and 12 location-years were conducted with 5 rates of N applied in the fall and as spring-preplant. Sidedress N was also included at 1 of the 4 locations for 4 years. Relative efficiency of the times of application was calculated by dividing the corn (Zea mays L.) yield increase from a given rate of N added at one time by the yield increase from the same rate of N applied at another time.
At the Carthage and Hartsburg locations the 3-year average relative efficiencies of fall- versus spring-applied N are about 0.8 and 0.9 (fall was 80 and 90% as effective as spring) at N rates of 67 and 134 kg/ha, respectively. Fall and spring N were about equally effective at 201 and 268 kg/ha of N. There was generally little yield response to N rates greater than 201 kg/ha at Carthage and Hartsburg. Fall and spring N gave similar corn yields for all rates of N at Urbana.
For the 4-year average at DeKalb, sidedress N was the most effective, spring N was intermediate, and fall-applied N was the least effective. The difference between spring and sidedress N was less than that between fall and spring N.
There was considerable year-to-year variation in relative efficiency. The importance of the time at which conditions suitable for N loss occur is discussed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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