NDSU Extension - Mercer County


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Harvesting, Drying, and Storing Late Maturing and High Moisture Corn

corn, corn harvesting, corn drying, late maturing corn, high moisture corn, corn storage

Submitted by Craig Askim, Extension Agent, Agriculture and Natural Resources

Corn reaching maturity about October 1 will normally dry slowly in the field due to cooler ambient temperatures. Standing corn in the field may dry about 1.5 to 3 percentage points per week during October and 1 to 1.5 per week or less during November, assuming normal North Dakota weather conditions.

Corn has a moisture content of about 32 percent when it reaches maturity. If it has a moisture content of 32 percent on Oct. 1, it may only dry to about 22 percent moisture by Nov. 1, assuming normal North Dakota climatic conditions. Field drying normally is more economical until mid-October, and mechanical high-temperature drying is normally more economical after that.

Assure corn stalks and shanks are strong if considering leaving very high moisture corn in the field. Field losses can range from minor to severe. Compare the cost of drying versus losses associated with leaving the corn in the field. The propane cost per bushel per point of moisture removed can be estimated by multiplying the propane price per gallon by 0.02. For example the cost to remove10 points of moisture using $2.00 propane is $0.40. Dividing the propane cost by the corn price provides the percentage of corn losses that will equal the drying cost. ($0.40/$3.00=0.13 or 13%) Also, verify the impact on insurance of leaving the corn in the field.

Storage in a poly bag is a good storage option, but it does not prevent mold growth or insect infestations. Grain should be dry when placed in a grain bag. Higher moisture corn in a bag should be considered as very short-term storage and only at near freezing temperatures. Select an elevated, well-drained location with the surface prepared to prevent punctures for the storage bags, and run the bags north and south so solar heating is similar on both sides of the bag. Wildlife can puncture the bags, creating an entrance for moisture and releasing the grain smell, which attracts more wildlife. Monitor the grain temperature at several locations in the bags. 

Corn above 21 percent moisture should not be dried using natural-air and low-temperature drying to minimize corn spoilage during drying. Because the drying capacity is extremely poor at temperatures below 35 to 40 degrees, little drying is typically possible using a natural-air system after about November 1. Adding heat does not permit drying wetter corn and only slightly increases drying speed. Turn fans off during extended periods of rain, snow or fog to minimize the amount of moisture the fans pull into the bin.  Using the maximum drying temperature that will not damage the corn increases the dryer capacity and reduces energy consumption of a high-temperature dryer. Removing a pound of water requires about 20 percent less energy at a drying air temperature of 200 F than at 150 F. Follow the dryer manufacturer’s recommendation.

Removing debris that accumulates on or in a dryer is more critical when outside air temperatures are cold because condensation can develop on the dryer, creating a wet surface on which debris can collect. The debris may reduce airflow through the dryer, decreasing the dryer’s capacity and creating a fire hazard.

Source: Kenneth Hellevang, Ph.D., P.E. Extension Agricultural Engineer & Professor

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