Farmers have learned the message Bob Nielsen taught them well. Starting two decades ago, he emphasized the importance of establishing evenly-spaced stands that emerge uniformly. Much of his early emphasis was on planter maintenance and west-up. Back then, standard deviations of 4 to 5 weren't uncommon. Perfect would be zero, but a standard deviation of 2 will probably get you by with no yield loss. Today, more people are approaching 2 than ever before.
That's good, and means plants should be evenly spaced in more Hoosier cornfields today. The other secret is emerging at about the same time. Over time, farmers have taken 'the same time' to mean within the same day or tow. Now Tony Vyn, another Purdue University Extension specialist, indicates that plants that emerge 2 days apart can still yield the same. He ahs concentrated work on determining what it takes to make sure each plant in high-yield systems gets an equal shot. Borrowing form President Bush' education program of about 10 years ago, his theme is 'no plant left behind."
"We've found that if plants come up a couple days late, they aren't necessarily the ones that are barren in the fall when you walk fields," he says. He and graduate students have flagged plants and followed them through the season to reach these conclusions.
If a plant come sup after its neighbors are a whole V-leaf stage ahead, then that's a different matter, he notes. Then the late emergers can produce barren plants or act like weeds, pulling nutrients form plants which will contribute a fair share of grain to the overall final corn yield within the field.
What does matter, Vyn says, is how each plant is treated, and how it finds nutrients. Each plant needs equal access to nutrients. Some of the variables that affect this you can't control- such as weather that affects nitrogen losses and weather effects in general. However, management practices are under your control.
"That's where planting correctly pays off," he says. "There are things like where the tire ran and created soil compaction that also play a role in final outcome. That's because they can affect soil rooting.
What Vyn is trying to determine is how to design management practices in the future so that each plant gets a fair chance at what's available.