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Apply nitrogen with corn plant in mind


Corn after corn on irrigated ground on Del Unger’s farm near Carlisle may receive as many as five to six applications of nitrogen. The last few applications, often with zinc added, are applied as 28% N through irrigation. The Ungers are prepared to inject N and other nutrients until tasseling if necessary.

Key Points

Nitrogen program may need to be designed differently for corn after corn.

Starter application of N fertilizer important in corn-after-corn situations.

Multiple applications of N could pay on sandy soils where leaching is more likely.


Even on nonirrigated land, the Ungers break up their N application during the year. The goal is to apply some N preplant, then apply a healthy dose of N as starter fertilizer. To increase the amount of nitrogen in the starter fertilizer, they mix 28% with 10-34-0. Then after the corn emerges and takes off, they typically sidedress with additional nitrogen.

Corn-after-corn angle

Applying ample nitrogen as starter fertilizer in corn after corn is important, notes Jim Camberato, a Purdue University Extension agronomist. “You’ve got a lot of residue out there in that situation, and you need to increase the N rate of starter fertilizer applied,” he suggests. “We would recommend 40 pounds of N or more as starter in that situation, especially if it’s a no-till field.”

Camberato doesn’t see much advantage for splitting up N applications several times, except on sandy soils. Since N can leach through sandy soils quickly, he sees an advantage for making multiple applications instead of one larger one if you’re set up to make it work. If you can inject 28% N through irrigation water, such as the Ungers can, then the practice should pay for itself.

This article published in the June, 2011 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.