How much do you know about one of the key crops you raise? Does the original corn seed stay belowground or come aboveground when it germinates? When is the growing point aboveground? How do these things affect crop management?
Your crop is well past the stage where the growing point is aboveground by now. However, it’s still a good time to stop and reflect on the basics of corn growth, notes Dave Nanda, a crops consultant with Seed Consultants Inc., which sponsors Crop Watch ’16.
Recently, Nanda visited the Crop Watch field and illustrated several points, including what you can learn about early corn growth even when a plant is working toward waist-high height. Here are two key lessons from his visit. He considers them part of Corn Growth 101, a refresher on how corn grows.
1. The seed germinates and the first root emerges. The seed stays in place in the soil.
Even now you could dig up a plant and likely find the old corn seed, Nanda says. If you wonder about depth placement, this is a way to determine — even this late in the season — how deep the seed was planted. You can’t do that with soybeans, because the seed splits and becomes the cotyledons that pull themselves above the soil surface. But you can with corn.
That’s because the first root — a healthy, white root headed downward and still visible if you dig up seven- or eight-leaf corn — is still connected to what remains of the old seed. The first root out is a lifeline that helps the plant begin to pick up nutrients from the soil, Nanda says. Then other sets of roots begin to emerge, and a healthy root system develops.
2. The growing point sits way aboveground between the fifth and sixth leaf stage.
To understand early corn growth, you need to find the growing point inside the stalk, Nanda says. To do so, simply hold a stalk in your hand and carefully split it lengthwise with a knife. As you work toward the base of the plant in seven- or eight-leaf corn, you will find what appears to be a point or a wedge growing inside the stalk.
“That’s the growing point,” Nanda says. “Once it is aboveground, then corn is vulnerable to catastrophic damage. In other words, if there was a freak frost or a hailstorm and the growing point was injured or destroyed, the plant likely wouldn’t recover.
“If the growing point is still below the ground, you can have those types of traumatic events and the plant will likely grow back and survive. Soybeans are vulnerable as soon as the cotyledons come aboveground, because they are the growing points."