Evaluate corn stalk strength prior to harvest
Knowing stalk strength can help prioritize fields that should be harvested first.
September 25, 2018 - Author: Bruce MacKellar
The 2018 growing season has been pretty quiet in many locations across southern Michigan when it comes to thunderstorm activity. While we have not seen too much in the way of severe storms this year, there is always potential for this to change as we move into the harvest season.
When warm air lingers over southern Michigan into late September and October, invading cold fronts tend to pack a significant punch in terms of wind and heavy rains. This is an excellent time to evaluate stalk strength in corn fields to prioritize which fields and hybrids should be harvested first.
Stresses on the plant can tend to lead to decreased stalk strength. We often think about common lodging factors such as corn rootworm or corn borer activity. However, brief periods of drought stress following nitrogen sidedress operations in 2018 did lead to some instances of temporary nitrogen deficiency, which can impact stalk integrity.
While the season was somewhat dry, leaf diseases such as gray leaf spot and northern corn leaf blight did impact some fields planted to susceptible hybrids. A new corn disease in Michigan, tar spot, has the potential to be very damaging to leaf tissues. Leaf tissue loss often leads to excess scavenging of carbohydrates from the stalks to provide for the developing kernels. Whenever this happens, there is a good chance that stalk strength will be compromised.
Michigan State University Extension recommends evaluating fields for stalk strength going into harvest. A simple push on the plants about ear height can help determine the stalks ability to withstand wind. Select rows at random and push on a number of stalks to see how many of the plants fall over. Look at a significant number of plants (25 or more) in several locations of the field to be able to calculate a percentage of stalks that are prone to lodging.
Knowing stalk strength can help producers to prioritize fields that need to be harvested earlier rather than later. These decisions can help to protect yields by reducing lodged corn.