This corn plant at the V4 to V5 stage has no nodal roots due to low ground moisture, but it developed seminal roots farther down.
Proper planter calibration can minimize problems
Each spring at planting time, farmers find themselves faced with a type of Goldilocks syndrome: soil conditions that are too cold, too wet and hardly ever "just right." This year, conditions might be too dry, which can contribute to rootless corn syndrome, or floppy corn.
Bob Nielsen, Extension corn specialist at Purdue University, saw the rootless corn phenomenon in fields across much of drought-hit Indiana in 2012. Iowa, Illinois and Nebraska farmers also saw the problem.
The syndrome typically occurs in young corn plants as a result of limited to no nodal root
development, he says.
"The nodal roots may have stopped developing because the upper soil conditions were too dry," Neilson says. "Young roots that emerge from the crown area of the plant will die if their root tips dry out prior to successful root establishment in moist soil.
"Affected plants lack all or most nodal roots," he adds. "Existing nodal roots may appear stubby, blunt and not anchored to the soil."
Nodal roots are critical to good corn growth and development, as they provide the majority of water and nutrients to the plants.
Rootless corn is caused by weather conditions, planting depth or a combination of the two, says Greg Kruger, University of Nebraska-Lincoln cropping systems specialist.
Nielsen adds that furrow or sidewall compaction; hot, dry soil conditions during early V2 to V4 root development; and loose or cloddy soil conditions can create an environment for rootless corn development.
"You may see rootless corn result if the seed furrow opens up after planting, often in dry conditions," he says.
Plan for prevention. Proper planter calibration and consistent planting depth can help minimize problems.
"Farmers need to make sure they plant between 1.5" and 2" deep consistently across their fields," Kruger says.
Farmers can sometimes see rootless corn appear in patches across a field due to how their planter is calibrated.
"The planter may be properly calibrated for parts of the field, but in areas of heavy soils or compaction, it may push the planter units up—resulting in seeding depth that’s too shallow for root development," he says.
Farmers will want to adjust their calibration within fields and also between fields, as soil variations dictate. "You may want to add a little more down pressure or set the planter one notch deeper to prevent the problem," Kruger says.
Once the corn crop is planted, there is little that farmers can do to manage rootless corn, says Tom Hoegemeyer, agronomy professor at the University of Nebraska. "Pivot irrigation and cultivation are probably the only management tools available," he says.
Nielsen adds that cultivation might support new root development if rain does eventually fall.
However, that won’t automatically eliminate the issue. "These plants may not form fully normal root systems and may be vulnerable to heat and moisture stress and nutrient deficiencies, even under good growing conditions," Hoegemeyer explains.
In addition, rootless corn increases the risk of lodging in the fall at harvest.
If rootless corn does show up in fields this season, Kruger tells farmers to dig corn plants and examine root systems to confirm the problem.
You can e-mail Rhonda Brooks at firstname.lastname@example.org.
- Mid February 2013