The Indiana Certified Crop Adviser panel includes Danny Greene, Greene Crop Consulting, Franklin; Brian Overstreet, soil conservation coordinator, Rensselaer; Dan Quinn, Purdue Extension corn specialist, West Lafayette; and Dan Ritter, Hoegemeyer Hybrids, Rensselaer.

 

It felt like I left half my corn crop in one of my fields this year. Well, not really, but there were ears scattered everywhere I looked in that field. What could be the cause? Are there combine settings that can combat this issue next year?

 

Greene: First, determine whether the ears were on the ground before harvest. If so, weak ear shanks may be the problem. European corn borer or other insects can damage the shank, diseases such as diplodia can weaken the connection, and weather can contribute to poor shank development or ear drop. Hybrid differences can also be significant.

 

If ears are dropping during harvest, look at the corn head and combine operation. Deck plates set too wide can allow small ears to fall through, while improper ground speed or gathering chain speed can cause ears to bounce out of the head. Head height is important, too, particularly in lodged corn.

 

Stop periodically and check behind the combine. Determine whether the loss occurred before or during harvest, then adjust deck plates, gathering chain speed, ground speed and head height as field conditions warrant.

 

Overstreet: If the droppage was before the combine entered, look at your hybrid’s ear shank rating or see if you have had European corn borer damage. The European corn borer can damage the shank and cause ear droppage. If these are the causes, assess next year’s seed selections to find hybrids with improved qualities in these issues.

 

If the ear droppage is caused by the combine, several settings could be tweaked. First is your ground speed matching the gathering chain speed. If you are going faster across the field than your gathering chains are taking the crop in, that can be an issue. Make sure your stripping plates are set to the proper width. They should be wide enough for the stalk to go through but narrow enough to stop the ear. You should also check the speed of your snapping rolls.

 

Quinn: One way to estimate how much yield is being lost out the back of the combine is to harvest a short, representative pass — approximately 20 feet. Stop the combine and count the number of kernels remaining on the soil surface within a defined area behind the machine. Approximately 20 kernels within a 2.5-foot by 4-foot area represents about 1 bushel per acre of harvest loss.

 

Overall, it is important to regularly check harvest losses and adjust settings such as fan speed, deck plate spacing, concave clearance, rotor or cylinder speed, and ground speed as field and grain conditions change. Newer technologies that sense and monitor grain losses directly on the combine may also help operators identify excessive losses and make quicker in-field adjustments.

 

Ultimately, taking the time to measure harvest loss and fine-tune combine settings can help keep more grain in the tank, particularly when harvesting very dry corn.

 

Ritter: There could be several items that cause ears to drop. Late-season scouting can help eliminate some of the potential causes.

 

There are a couple possibilities here. Combine settings or using hybrid with weak shanks are a couple of them. It could be a combination of both. For example, environmental stress on the corn could have caused weak shanks, and then aggressive combine settings caused dropped ears.

 

Take note of the ear size. Undersized ears may have had severe stress, nutrient deficiency or could have been late emergers. Next year, make that last late field scouting trip to document any issues ahead of harvest. Then, monitor combine settings closely during harvest and make the appropriate adjustments.