To Replant or Not to Replant, That is the Question!

Calendar moves into dicey zone for much of country.

Published on: Jun 6, 2011

Maybe you've got 40 acres that just didn't come up well and the stand is average to terrible. Or maybe you've just got a handful of four or five-acre ponds that are about dry enough to plant again, but which were taken out by big rains. Is there still time to put them into corn or not?

It's the witching hour in many people's minds, depending upon where you live. Here's what the Purdue University Corn and Soybean Field Guide says about replanting. Much of the data is based on work similar to that done by Bob Nielsen, the Nebraska native who has been the Extension corn specialist in Indiana for three decades. He's also the mastermind behind the Chat 'n' Chew café on the Web. The particular table chosen for the Field Guide is from a study by Emerson Nafziger at the University of Illinois.

The odds are definitely not in your favor, except for a favorable corn harvest price. However, there are anecdotal stories about planting in mid-June in the central Corn Belt an still harvesting a 'good' crop, with good being 140 to 160 bushels per acre. If you've got chemical down and don't have another option, you might want to run the numbers.

If you planted this past weekend at 28 to 32,000 plants per acre, on average you can still expect 75% of yield potential. If it's a good field and your legitimate goal was 200 bushels per acre, that's still 150 bushels per acre, at even $6 per bushel is still $900 gross income.

However, the numbers begin to fall rapidly. By June 9, it's 67%, or about two-thirds. Now you're at 135 bushels per acre, more or less. That's still $810 gross income potential.

With soybeans, upping the population for later planting helps. With corn, there's no evidence that the same phenomenon happens. That's because corn and soybeans compensate in different ways. In fact, yield declines for anything above 32,000 plants per acre planted this month. Surprisingly, if you plant June 9 and can get 20,000 plants per acre, you can still achieve about 120 bushels per acre playing the averages, or about 120 bushels per acre in our original 200 bushel per acre field. That's still a gross of $720 per acre.

The problem comes on the other end of the cycle. Will the crop mature in time? June 9 is the last date listed in the planting chart. Switching to an earlier hybrid if available may help you beat a frost or harvest at a lower moisture content. But most seedsmen say you may give up 20 bushel per acre in yield potential going with a shorter-season hybrid that didn't have the same yield potential in the first place. For example, if you switch from a hybrid that would have delivered 200 bushels per acre to one that under the best conditions, planted May 1, would have yielded 180 bushels per acre, now you're already down when you start figuring percentages.

The biggest thing going for you is a good selling price. If you can lock that in or if you've already locked one in and need corn to fulfill contracts, it may affect your decision making process.  

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