Determining why young plants fail to launch

May 23, 2021

Whether your corn looks great or has yet to kick into high gear, Dave Nanda, Ph.D., SGD’s director of genetics, believes now is a good time to scout fields and assess crops.

While growers can’t control the weather (unseasonably cool weather that lasted until mid-May may have impacted germination and growth for planted corn), Nanda also looks for things which growers can control, such as correctly dialing-in a planter and avoiding soil compaction.

“Soil compaction comes in various forms,” said Nanda, “including crusting from heavy rains, usually more intense on conventionally-tilled soils, and sidewall compaction within the seed trench caused by planting when soils are still tacky. The best way to evaluate these things is to carry a shovel and dig a few plants. I understand farmers don’t like to see plants destroyed, but digging a few plants in key locations can unlock keys which may lead to better management decisions in the future.”

When Nanda digs, he tries to dig both a perfectly healthy plant and one that might be struggling, both in the same area, for good comparisons. The struggling plant may be smaller or may be off-color. Flagging plants as they emerge can help determine if a smaller plant is struggling or just if it just emerged later.

To examine plants, Nanda holds them side-by-side to compare root growth. He looks at depth of roots; branching of roots; and the number of developed finer, white root hairs. Branching roots and hairs are a positive sign.

If he finds a plant with root issues, his next move is to examine the soil more closely. Is there evidence of soil compaction where the small plant was growing? If so, is soil compaction also evident where the healthy plant was dug? Soil compaction near the surface may slow down root development.. Sometimes if soil is compacted a bit deeper, it will come out in chunks around the plant.

Nanda also looks for gaps between plants where another plant should have emerged but is missing in action. Experience has shown him that about four times out of five, it’s not a planer skip. Often, when he digs to planting depth, there is a seed. It simply didn’t emerge.

“Assuming it was the planter’s fault every time might cause you a lot of effort chasing a problem that didn’t exist,” Nanda said. “Typically, seed bags list germination around 95 percent. That means there will be a seed here and there which doesn’t germinate. In other instances, a seedling leafs-out underground while trying to emerge. It’s difficult to determine what might have happened to these isolated seedlings.”

The bottom line is that by checking, one cause —planter failure— is eliminated.