One take-home message from the Corn Illustrated Plots harvested late last fall had nothing to do with the intended purpose of the trial. Sometimes it's the observations you make about other things that turn out to be as or more valuable than the subject you started out to study.
That was true in the case of the population trials in the plots located near Edinburgh, Ind., in the south-central part of the Hoosier state. The most obvious conclusion was that one of the two hybrids yielded more than the other. Yet in almost every other plot around Indiana and Ohio where the two hybrids went head to head, the results were flipped. The explanation for the reversal in this plot boiled down to stand- plants per acre. The hybrid that typically wins plots where both hybrids are included ran 4,000 to 5,000 plants per acre behind its' counterpart in almost every treatment in the Corn Illustrated population study.
Earlier, we tracked the cause to a tough stretch of weather right after planting that put hybrid vigor to the test. Apparently one chink in the armor of the better- yielding hybrid is the ability to emerge quickly and evenly under extreme conditions. The stand started out thinner than desired from the very beginning.
Fewer plants translate into fewer ears and less yield. The relationship between 1,000 plants per acre and about 7 bushels of yield per each 1,000 plants, up to some sort of reasonable limit, has been established in the last couple of years. So if the two hybrids started out 4,000 plants apart, that's worth 28 bushels per acre. If the thinner hybrid is naturally better yielding if everything is even, you would have expected it to gain some of that back.
And it did. But the difference was too much to make up entirely. In most cases it amounted to a 7 to 20 bushel per acre difference at a given population level for the thicker hybrid over the thinner hybrid that usually excels.
Weather was the cause of a thinner stand in these plots. But in other instances a poorly-serviced planter could be the cause. If the planter isn't adjusted properly and checked thoroughly, it could also lead to uneven spacing, even if all the plants are there. Purdue University corn specialist Bob Nielsen demonstrated more than a decade ago that uneven stands can reduce yields, typically by as much as 5 to 7 bushels per acre.
Now is the time to plan for servicing your planter. There's about 12 weeks before time to pull it to the field and go hard, weather permitting. In the meantime, agronomists suggest having units checked for accuracy on test stands. Usually there's an equipment dealer who offers this service at minimal cost. In some cases seed dealers offer it either at a nominal price, or as a service to customers.
Devote the time it takes to getting your planter into top shape, specialists suggest. Don't be the cause behind why your stand is thin.