Operating a Drago corn head can help reduce yield loss in the fall.

Environmental and soil conditions that create plant variability in a corn crop cause potential yield loss from the day it’s planted all the way through corn harvest.

Making adjustments to account for corn yield variability – throughout the growing season – is critical, as some will result in harvest yield loss when the combine runs this fall. Outfitting the combine with the right equipment, like a Drago corn head, can help minimize losses that occur in variable conditions.

“There are multiple factors that cause stalk and ear size variability within a field – and even within every acre – due to different microenvironments,” says Dragotec USA president and Fenton, Iowa, farmer Denny Bollig

Variability factors

Bollig lists six variability-causing factors that can cause potential yield loss at harvest.

1) Soil type

Soil type, including factors like organic matter, soil pH and water retention, is a major driver of inconsistent plant size that leads to corn yield variability.

“When you move across the field from one soil type to another, one type may grow bigger plants than the next,” Bollig says. “Soil type changes don’t happen in straight lines. I have fields that may have anywhere between five and 20 soil types. That can cause major plant size variability.”

2) Soil drainage

Soil drainage is one of the most noticeable causes for plant variability. The ability for soil to drain excessive moisture goes a long way in determining how variability earlier in the growing season manifests itself as yield loss at corn harvest. Variability caused by inconsistent soil drainage across a field is also complicated by plant populations and hybrids.

“You can drive down a road and see areas in some fields where the corn is taller and greener, and areas where it’s shorter and more yellow. That is likely because of moisture stress,” he says. “Drainage is not consistent across any field.”

3) Crop residue

The amount of crop residue present in your fields in the spring depends largely on your production practices. And there’s more than just the amount of actual residue contributing to potential yield loss. The location of crop residue in the field during and after planting can have a big effect on how much corn yield variability it can create.

“If plant residue gets into the furrow, some seeds may have residue right next to them, while others may not,” Bollig notes. “That will impact soil temperature, and you will see differences in emergence, vigor and plant sizes.”

4) Topography

While precipitation, frost and wind are major drivers for in-season crop variability, don’t neglect how their effects on plant growth are influenced by topography. This is especially true when assessing specifically how these weather variables affect corn yield potential.

“Sometimes frost isn’t uniform across a field, and topography can create huge amounts of inconsistency among corn plants,” he says. “With wind, some parts of the field have better protection than others, and you will have bigger plants in those areas that don’t fight the wind as much.”

5) Planting strategies

Planting dates and plant populations are major factors when it comes to overall crop variability. Earlier planting can affect emergence rates across the field and make seedlings more susceptible to early frost damage.

“Farmers are also pushing plant populations higher, which magnifies environmental stressors that can result in smaller plants and ears. Those small ears increase the potential for yield loss through the deck plates of the corn head,” Bollig says.

“We’re growing more ears per acre, but as you move through fields with different soil types and weather-related issues, producers may encounter a significant amount of corn yield variability.”

6) Corn yield

It may seem unlikely, but Drago research has demonstrated stalk width variability increases in higher-yielding areas of the field.

“We were surprised to see how much stalk width changed as we harvested higher-yielding areas of the field in our research,” he says. “When the yield monitor ticked above 200 bushels/acre, we were seeing row-to-row plate gaps varying by ¼ inch or more 40% of the time, and deck plates made two ½-inch adjustments every second.”

Counteracting and minimizing variability

Though plant and ear size variability are inevitable, farmers can take steps to minimize its influence on yield loss. Accounting for soil type and pH through soil testing and nutrient management can help create more consistent fertility. Soil drainage can be improved by adding or replacing damaged tile lines.

Yet, some variability will remain by corn harvest, making it critical to best match harvest operation for the conditions you’ll face to minimize yield loss.

“Having a corn head with deck plates that match field conditions is critical to capturing corn yield from loose kernels and small ears,” Bollig says.

“Other than Drago corn heads, with their automatic self-adjusting deck plates, every other head has manually adjusted hydraulic deck plates. Operators are left to make adjustments based on their best guess about stalk width. And the plates are designed to have the same gap setting across the head. Drago corn heads take the guesswork out of harvest.

“We know that the best place for your deck plates is up against the stalks, and that’s going to minimize yield loss as variability inevitably occurs.”