High-moisture Corn Creates Storage Problems

Corn harvested at high moisture levels needs special care when it’s stored.

For example, corn at moisture contents exceeding about 23 percent should not be stored in a grain bin because the kernels may freeze together or deform and bind together, which could keep them from flowing from the bin during unloading, North Dakota State University grain-drying expert Ken Hellevang says. Corn above this moisture content should be placed so it can be unloaded with a front-end loader or other equipment that can dislodge the corn mechanically.

Providing aeration to keep the corn cool also is critical to prevent it from deteriorating rapidly. Corn will deteriorate even with airflow, but without airflow through the corn, it will increase in temperature, resulting in rapid deterioration. Hellevang recommends an airflow rate of 0.2 cubic feet per minute per bushel of stored corn.

“Condensation and icing occurs on bin vents at temperatures near or below freezing, so leave bin covers open to serve as a safety opening when operating fans near or below freezing temperature,” he says. “There were numerous reports last year of bin vents freezing over and the fan pushing the roof up and damaging the bin roof.”

Here is advice for ensiling high-moisture corn:

• Shelled corn should be at 25 percent to 35 percent moisture for anaerobic (without oxygen) high-moisture storage in silos or silo bags.
• Promptly repair any tears in the plastic bag to minimize storage losses.
• Whole shelled corn can be stored in oxygen-limiting silos, but a medium grind is needed for proper packing in horizontal or conventional upright silos.
• A bunker needs to be airtight. Make sure it is covered with plastic on top and the sides and sealed at the seams. Seal any punctures in the plastic. Exposure to air will result in spoilage and loss.
• Wet shelled corn exerts more pressure on the silo than corn silage, so producers may have to add hoops to conventional concrete stave silos or they should not completely fill the silo.
• Corn at moisture contents below 25 percent will not ensile, so it will need to be dried for storage. If oxygen is not adequately removed as the corn ensiles, heating and severe deterioration will occur.

Fines also can be a problem in high-moisture corn. More fines are produced when corn is wet because more aggressive shelling is required, which causes more kernel cracking and breaking. The potential increases as well for stress cracks in kernels during drying, which can lead to more breakage during handling. In addition, immature corn contains more small and shriveled kernels.

Fines cause storage problems because they spoil faster than whole kernels, they have high airflow resistance and they accumulate in high concentrations under the fill hole unless a spreader or distributor is used. Preferably, the corn should be screen-cleaned to remove fine material, cob pieces and broken kernels before it is put into bins.

Corn with damage to the seed coat and immature corn have a shorter storage life than mature corn. Therefore, cooling the grain to about 20 to 25 degrees for winter storage is more important for immature corn than for mature corn. Hellevang recommends drying the corn a percentage point lower in moisture content and checking the stored corn frequently. Immature or damaged corn should not be kept in long-term storage.

NDSU Agriculture Communication