Why There's No 50 Pound Rate in These N Plots

Farmers want to participate, but not take big yield hit.

Published on: Sep 22, 2010
Don't put any nitrogen on corn and it will still make a crop. It just may not be a very good one. Apply 50 pounds total N and it should make more than if you apply nothing. In fact, it may make more than you think. In Corn Illustrated trials for Farm Progress Companies a few years ago, in small plots, applying 50 pounds per acre still produced roughly 100 bushels per acre in one plot in one year.

"If we were just doing small plots, it would be one thing, but we're doing these replicated plots across the entire field," Kneubhler notes. "That was three strips across the field. If a farmer has a 24-row planter, each strip in the test is 24 rows. Three strips of 24 rows across a relatively long field amounts to quite a bit of acreage. Farmers simply weren't happy about taking that much yield hit, especially when corn is $4 or more per bushel."

Why would you want a 50-pound rate in an experiment anyway? "You need to establish the boundaries on both ends of the extremes," says Dave Nanda, now with Seed Consultants, Washington Court House, Ohio. Nanda also does crops consulting, operating out of his home in Indianapolis.

"If you're trying to establish how much nitrogen corn needs, you need to make sure the extremes are set wide enough so that on one hand, yield is a bit lower, and on the top end, you've obviously reached the point at which yield either begins to go down or doesn't increase any more. Then you can go back and determine the rate which is most economical."

The problem with not including a low rate is that you could run the risk of not being low enough. Perhaps plants could still do as well at 75 as 100, Nanda says. However, Kneubuhler believes that what he's seen visually from plots this year indicates that the most economical N rate in his area of northeast Indiana and northwest Ohio is likely to be higher than normal anyway. Combines will tell the true story as farmers run plots and report data from yield monitors to him to tabulate, but his instincts tell him this may be a year when more N was needed to reach optimum level. He works on mostly heavy clay soils in his area.