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Serving: IN

Adjust N Rates Up For Lower Price, Down for Cheaper Corn

Adjust N Rates Up For Lower Price, Down for Cheaper Corn
Purdue University research produces guidelines for maximum economic yield.

Before you select your nitrogen rate for your fields in 2014, you will want to take a look at "Nitrogen Management Guidelines for Corn In Indiana." It's a new article at the Chat'n Chew Café website maintained by Bob Nielsen, Purdue University Extension corn specialist.

If all you care about are top yields, you can find the rates recommended for various parts of the state based upon eight years of strip trials across Indiana. There is a 35-pound spread on average recommendations from one part of the state to another. If you look within the years of data for each location, there are also wide ranges depending upon the year. That's why the rates are called "guidelines."

Top economic yield: It's nice to fill the truck to overflowing at harvest, but the crop must turn a profit. That's where economic N rates enter the picture.

The most critical part of this article by Nielsen, Jim Camberato and Brad Joern may be the three tables that show how to find the rate to apply for commercial N fertilizer if you're after the maximum economic rate. In other words, how much N do you apply if you want to net the most profit?

Since there are three sections of the state with three different rates, there are three tables. You pick the price per pound for nitrogen, and selling price for corn, find the table for where you live, and determine the recommended optimum economic rate for N fertilizer.

For example, suppose you live in central Indiana. Then you would refer to Table 3. If N costs you 40 cents per pound, and you expect $3.50 corn, you would stop at 191 pounds per acre. The optimum for agronomic top yield without considering cost in that region is 217 pounds per acre.

If you can buy N at 40 cents per pound and expect $4.50 per bushel corn, you could jump the rate to 197 pounds per acre.  However, if you pay 50 cents per pound of N and expect $4 corn, the recommended rate in your region would be 189 pounds per acre.

In northwest Indiana at the 50 cent N price and $4 corn, the rate would be 173 pounds per acre. In west-central Indiana the recommended top economic rate for the same prices would be 161 pounds per acre.

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