You've heard talk for years that if your planter doesn't do a good job and you don't space seeds correctly, you can lose yield. It's easy to say, but harder to visualize. Well, look at the picture again. That's about as visual as it gets.
The corn stand on the right side is close to a picket fence stand. It's probably as accurate as you can get with today's equipment. Then look at the stand represented on the left side of the board. It's about as inaccurate as you would find.
These stalks weren't just pulled and placed on the board for a demonstration. These are real world stalks from real rows, placed at the exact differences they were in the field. Most rows were planted like the row on the right. One seed meter experienced bug problems, producing the row on the left. Since the farmer had high-tech monitors in the cab, in this case a 20/20 Seed Sense monitor from Precision Planting, he was alerted that one row wasn't singulating properly. Before he decided to stop and investigate, he got the spacing you see on the left.
Joe Kosta with Ceres Solutions and also affiliated with Winfield, pulled the stalks and made this demonstration. "When singulation goes from 99% to 96% on a row on a monitor that displays that information, you need to find out why it's dropping," he says.
People who study row spacing calculate standard deviation. It's a measure of how close the stand is to the spacing you selected. The more variable in the stand, the higher the standard deviation will be. Researchers like Bob Nielsen at Purdue University have discovered that if you can hit a standard deviation of 2.0 or less, you likely aren't affecting yield. If it rises above that you begin to affect yield.
Kosta says the stand on the right is at about a 1.5 standard deviation, which is a very good stand. The one on the left is at around 4.0, a stand with problems. Notice the difference in ear size when the plants are too close together. He believes that row would definitely yield somewhat less.