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Corn Watch: You can take weeds out of corn, but not corn out of corn.

Dave Nanda

June 26, 2017

3 Min Read
BULLETPROOF ‘WEED’: A small corn plant grows next to normal, much larger plants within the same row. Small corn plants are actually worse than weeds because you can’t get rid of them.

Last year while scouting the Crop Watch (now known as Corn Watch) field with Tom Bechman, Indiana Prairie Farmer editor, we noticed several puny corn plants growing in rows of knee-high corn. If you recall, last spring was similar to this spring. There was cool, wet weather after planting. The grower who lets us visit his fields for the Corn Watch project spotted in replant corn both last year and this year.

This year, when we found the same puny plants while scouting knee-high corn, the following conversation unfolded.

Bechman: Hey, Dave, these little plants won’t contribute much to yield, will they? Actually, they’ll be like weeds and compete with the normal plants for nutrients, water and sunlight.

Nanda: Tom, they’re worse than weeds.

Bechman: How can they be worse than weeds?

Nanda: Because we can kill weeds with postemergence herbicides if we find them soon enough, but we can’t kill little corn plants with those herbicides. They can’t even be killed with cultivation because they’re within the row.

Bechman: Where do they come from and what can we do about them?

Nanda: There are many ways we can have these little corn plants within the corn rows, even when we don’t have replant situations. During seedbed preparation, if the field is worked when it isn’t fully dry, we’re going to have some cloddy situations. Seeds may be planted at different depths and might not germinate uniformly. Seedlings that emerge even a couple days later are going to have a disadvantage and may not be as tall as their neighbors. Chances are they’ll never catch up and may produce no ears or nubbins.
Bechman: OK, that’s one factor. What else could cause late-emerging plants?

Nanda: When we have a wet spring like this year, growers are anxious to get seed in the ground and may plant faster than they should. It can affect seed depth variability. Even though we have excellent precision technology available so growers can plant faster with good precision, the number of such planters being currently used isn’t very high.

Improper closure of the seed furrow can also affect germination and emergence. These are planting basics, but when we have lots of acres to plant and the weather window is closing, it’s easy to hurry and not pay attention to details.

Bechman: What about seedlings emerging about the same time, but still ending up smaller than their neighbors?

Nanda: Most seed companies try their best to do a great job of detasseling. However, it’s virtually impossible to remove every tassel from female rows. So some seed harvested may be seed of a female inbred parent. It’s less vigorous than hybrid seed.

Bechman: It’s too late to do much about this for 2017. What’s the take-home for 2018?

Nanda: Growers who get high yields plant their cornfields so all seedlings germinate at about at the same time. Once seedlings emerge, it’s off to the races and survival of the fittest. Each plant will try to dominate its surrounding zone of influence and capture as much sunlight, water and nutrients as it can. It’s really a jungle out there! You need to minimize the number of plants that are worse than weeds. They can rob you of yield.

Nanda is president of Agronomic Crops Consultants LLC. Email him at [email protected], or call 317-910-9876.

About the Author(s)

Dave Nanda

Dave Nanda is director of genetics for Seed Genetics Direct, Jeffersonville, Ohio. Email [email protected] or call 317-910-9876. Please leave a message.

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