Corn growers: If you haven’t already done field yield estimates for your corn crop, you should. That way, you’ll have a better idea of your yield guestimates when you fire up the combine and head out to your fields in a few weeks. As a reminder on how to calculate your corn yield estimate, use the following formula:
- Take 1/1000 of an acre, or 17 feet, 5 inches in typical 30”rows. Count the number of harvestable ears. You generally have fewer plants than your initial seeding rate and not every plant may have a harvestable ear. Example: Planted 34,000 seeds /acre, 29 harvestable ears.
- Take 3 ears from the beginning, middle and end of your 1/1000 of an acre and average the numbers of kernel rows around the ear. Kernels around should always be an equal number. Example: 16 +16+14 = 46. Divide by 3 = 15.33 rows around
- Then count the length of your kernel rows. But don’t count the tiny kernels on the end, or the irregular kernels on the butt of the ear. Example: 40 + 33+ 35 = 108. Divide by 3 = 36 kernels long
- Now that you have kernels around by kernels long, you can find your estimated yield, or bushels per acre, by multiplying the ear count by kernels around by the kernels long divided by 90. The reason you divide by 90 is because there are roughly 90,000 kernels per bushel. Example (29 x 15.33 x 36)/90 = 178 bu/A.
- It’s always a good idea to repeat this estimate several times to get a more accurate result.
Heat Can Reduce Grain Fill
While the USDA World Agricultural Supply and Demand Estimates report has projected an oversupply of corn in the U.S., keep in mind that while the national level is important, the individual field level is most important to a farmer. An often overlooked factor that will affect yields this year are the hot nights in addition to hot days. Many Ohio growers experienced summer days with temperatures in the 90s, and also summer nights in the 80s. This makes a big difference in yields because corn plants make sugar during the day, but if it’s hot at night, they burn most of the recently built sugars in respiration. With energy burned comes a loss of grain fill.
To protect corn crops from being hit by a double heat wave in 2017, take a look at hybrid temperature tolerances as you evaluate Golden Harvest® Corn and NK® Corn seed selections. It also doesn’t hurt to look at how estimated hybrid heat tolerance ratings stack up to actual yield numbers once harvest is kicked off this year. Spreading risk through genetic variety means that some hybrids will perform better in a hot year and some will perform better in a cool year. Don’t forget there are many other factors that go into final hybrid performance – everything from planting depth to weeds, disease, insects, rainfall, nitrogen levels and more.
To experience additional agronomic insights firsthand at the Marysville Grow More™ Experience site, contact your Syngenta representative.
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