Opinions vary on whether to cut N rate


Everyone has one. That field planted the wrong day where the stand isn’t what you like. Suppose you wanted 30,000 plants per acre, but have 25,500 instead. Worse yet, the range is 15,000 to 32,000 plants per acre. You were going to sidedress 180 pounds. Should you cut back?

Jesse Grogan says “no,” but not everyone agrees. Grogan, an Indiana Certified Crops Adviser, is with LG Seeds, Lafayette. He’s basing his decision on the fact that the yield potential may not be affected much. That’s reflected in tables used by insurance adjustors in hail situations, assuming the field was planted on time.

Find the table at www.kingcorn.org/news/timeless/haildamage
youngcorn.html.

“Plant stand varies within the field, but it’s difficult to adjust N rate on the go,” Grogan says. “Some plants will receive more than needed, but will have maximum potential of yield. My advice is to use the initial N rate that was determined for original yield potential.”

Second opinion

“This is challenging,” says Greg Kneubuhler, also a CCA, with G&K Concepts, Harlan. “The population range alone will significantly affect overall yield potential. The 32,000 areas will obviously require more N than the 15K population areas.

“Based on what I know I would probably reduce my sidedress rate some, assuming we’re fertilizing a 25,500 stand. Even at 25,500, depending on planting date, we’re only losing 6% to 8% yield. The only other variable is how consistent the stand is. Reducing nitrogen by 10% should be a safe place to sidedress.”

That’s significant, however, since 10% of 180 is 18 pounds. At 50 cents per pound, that’s $9 per acre. Yet at $6-per-bushel corn, 1.5 more bushels per acre would pay for the $9 of extra N. You make the call!

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

All rights reserved. Copyright Farm Progress Cos. 2011.