Drying Costs Versus Stalk Loss—Which Costs More?

Drying Costs Versus Stalk Loss—Which Costs More?
As fields inch toward harvest Mother Nature isn’t letting up. Downpour after downpour brought on by hurricane Gordon is leading to questionable stalk and shanks in corn fields.

With stalks and shanks threatening to break, are you prepared to harvest early? Does it make economic sense? Scout fields, weigh drying costs and remember, every bushel you leave in the field is potential dollars out of your pocket.

Step one: Scout fields. After plants hit, black layer quality begins to erode. It’s prime time to check stalk integrity with the pinch or push test.

Nitrogen-poor areas might be at greater risk of poor stalks because the plant ‘steals’ nitrogen from the stalk to feed the ear. If you had drought conditions, ran out of nitrogen or even excess water that led to leaching be mindful of weak stalks.

In addition, rainfall, humidity and field-present pathogens could lead to an outbreak in stalk rots.

“Regardless of which stalk rot pathogen causes the primary infection, the end result is the same: Yield loss due to lodging or premature plant death,” according to Wyffels ‘Between the Rows’ blog.

  • Lodging lays plants down, which could increase the severity of disease and make it difficult for corn heads to pick up what yield is left in the field.
  • Premature plant death can lead to drastic yield loss depending on how early it dies. Wyffels describes potential loss by stage:
    • Silk- whole plant 100% yield loss, just leaves 97% yield loss
    • Blister- whole plant 100% yield loss, just leaves 73% yield loss
    • Milk- whole plant less than 75% yield loss, just leaves 59% yield loss
    • Dough- whole plant 50% yield loss, just leaves 41% yield loss
    • Dent- whole plant 40% yield loss, just leaves 23% yield loss
    • Half Milk- whole plant 12% yield loss, just leaves 7% yield loss
    • Black Layer- no yield loss
“[Also] check shanks,” says Sue Brakhane, technical agronomist for Bayer in Iowa. “We have some diseases out there—watch for ear slip.”

Estimate drying costs before pulling the harvest trigger. When corn is starting to fall but still contains a considerable amount of moisture, put a pen to paper and calculate the optimal time to harvest.

On average, each percentage point of moisture removed by drying systems in corn takes 0.018 gallons of propane, according to researchers at Iowa State University (ISU) Extension. The range is from 0.010 to 0.025 gallons.

To find each field’s assumed propane cost:

Multiple assumed propane use (per bu.) X number of percentage points removed from each bu. X number of bu. to dry X price per gallon of propane.

If you’re using electricity to power fans, move grain or provide heat account for that cost, too. ISU Extension researchers assume 0.01 kilowatt-hour (kWh) per percentage point of moisture removed per bu. For natural air drying system, that use only electricity, assume average use rate of 0.33 kWh per point removed at a range of 0.30 to 0.40 kWh.

To find each field’s electric cost:

Multiply assumed use rate X percentage points of moisture to remove per bu. X number of bu. to dry X price per kWh of electricity

Find the cost of drying versus leaving crops to potentially lose bushels in the field to make the most informed decision you can—and maximize profit potential.

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