CORN NITROGEN FERTILIZER APPLICATION TIMING AND RATES
Applied Research
Wayne Flanary
Field Specialist in Agronomy
University of Missouri Extension
St. Joseph
Abstract
Four years of corn nitrogen fertilizer application timing and rate trials were conducted at the University of Missouri Graves Chapple Extension and Education Center located at Fairfax, Missouri. The trial’s objective is to determine if preplant 120-pound nitrogen rate followed by additional rates of nitrogen at V-8 and V-16 timing would increase nitrogen efficiency. There were eleven treatments as 0, preplant 120 and 240 nitrogen rate and 8 treatments with a preplant rate of 120 pounds nitrogen with two timings and four nitrogen rates. The two post application timings were applied at corn stage V-8 or V-16. The additional nitrogen treatments were rates of 30, 60, 90 and 120 pounds of nitrogen. The nitrogen source was urea treated with Agrotain. The experimental design was a complete randomized design with five replications. Yield results indicate preplant 240 pounds of nitrogen maximized yield at 221 bushels. The preplant nitrogen rate of 120 pounds yielded 198 bushels. All additional nitrogen rates and application timings increased yield compared to the preplant 120-pound rate. Yields were maximized with preplant nitrogen rate of 120 pounds and an additional supplement nitrogen rate of 90 pounds providing 210 pounds of total nitrogen. Mean yields for adding 90 pounds of nitrogen at V-8 were 220 bushels and V-16 were 219. The additional rate of 120 pounds resulting in a combined amount of total nitrogen of 240 pounds did not increase yields compared to 90-pound rate. In summary, yield data indicates a preplant rate of 240 pounds was not needed to maximize yield. Yield was maximized by 120 preplant nitrogen followed by 90 pounds at either V-8 or V-16.
Poster has NOT been presented at any previous NACAA AM/PIC
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Authors: Wayne Flanary
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Flanary, W. Field Specialist in Agronomy, University of Missouri Extension, Missouri, 64507