How the Ear Type and Plant Structure of Corn Hybrids Can Impact Yield
The annual corn crop average in the U.S. is 175 bu. per acre. This is noteworthy in light of the fact that premium-quality seed corn has the potential to produce approximately 500 bu. per acre. So why the disparity?
While yields can be negatively impacted by a variety of factors, including disease, insects and weather, it is unlikely that those factors drive yields down more than 300 bu. per acre. So what else is affecting yields?
Many farmers are unaware of how hybrid ear type affects the development of the crop. Corn ear type dictates planting population while the structure of the corn plant plays a significant role in its ability to capture sunlight.
When choosing hybrids farmers should focus on a few items. One is soil. Planting in sandy soil means that water management will be a critical consideration. Deep black soil, on the other hand, means hybrids will need to capture as much sunlight as possible.
The ear type and plant structure of hybrids also need to be taken into consideration when it comes to planting population. There are four types of plant structures to consider: upright, semi-upright, semi-pendulum or pendulum leaves.
Leaf structures that are upright get more sunlight. This is important if sunlight is limited. Corn hybrids with drooping leaves will maximize leaf area index at much lower populations. Semi-upright hybrids land somewhere in the middle.
Late-season plant greenness also needs to be considered if a particular hybrid flexes a great deal in kernel depth. Fungicides and nitrogen later in the season can increase kernel depth in these cases.
All corn hybrids flex downward. Therefore, when planted at a low population, ear size will be maximized and plants will get enough sunlight and nutrients. Crowd plants, however, and ear size will decrease. There also are different levels of flex in particular hybrids that need to be considered. Hybrids that flex in depth, girth and length are considered full-flex hybrids. Others, called determinate, flex only in depth of kernel. The rest flex somewhere in between.
While planting full-flex hybrids would seem likely produce the highest yields, these hybrids are also riskier because they don’t handle stress well. Determinate hybrids handles stress better and retain the same number of kernels but the size of the ear itself decreases.
In the end, while variable-rate practices can add yield, consistency is perhaps their greatest advantage. Therefore, the more information farmers can glean from own experience, coupled with advice from their seed corn rep concerning ear type and plant structure, the more likely they will be able to avoid massive yield swings from year to year.