NDSU Extension - Mercer County


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Alternative Grain Storage

alternative grain storage, grain storage, outdoor piles, storage bags

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

Grain can be stored in many types of facilities, but all storage options should keep the grain dry and provide adequate aeration. Grain must be dry and cool when placed into alternative storage facilities. Aeration to control grain temperature is a critical part of alternative storage, but it is not feasible to provide adequate airflow quantity and uniformity to dry grain in alternative storages. Also, grain should be near average outdoor temperature, because it is generally not feasible to provide enough uniform airflow for adequately cooling grain coming from a dryer. If it is stored in a building that was not built for grain storage, the wall of that building was not built to have grain pushing against it. Typically a grain wall including additional poles or structural support must be added for the building to be used.

The amount of the force exerted on the wall by grain can be estimated by multiplying the grain depth by the equivalent fluid density, EFD, of the grain. Since this force will try to move the base of the wall out, the wall must be anchored securely. Wall structural members must be strong enough to transfer the force to the building poles or support structure without breaking or excessive bending. The total force per linear foot on the wall is the force at the base multiplied by the grain depth divided by two.

Before placing grain in a building that has been previously used for grain storage, examine the building for problems by looking for anything that is out of alignment. Bowing or bending indicates that the load imposed on the building is exceeding the load for which it was designed. Examine connections looking for any separation or movement. A connector failure can lead to a building failure.

Storage in poly bags is a good storage option, but it does not prevent mold growth in damp grain or insect infestations. Grain should be placed in the bag at recommended storage moisture contents based on grain and outdoor temperatures. Because the grain cannot be aerated to control heating of damp grain, bagging damp grain is discouraged.

Select an elevated, well-drained location for the storage bags, and run the bags north and south so solar heating is similar on both sides.  Sunshine on just one side of the bag heats that side which can lead to moisture accumulation on the other side. Monitor the grain temperature at several locations in the bags.

Short-term storage is frequently in outdoor piles. Precipitation is a severe problem for uncovered grain. Grain has a void percentage of about 43%, so the grain is very porous. A one-inch rain will increase the moisture content of a one-foot layer of corn by 9 percentage points.  Aeration and wind blowing on the pile generally will not adequately dry the wet grain to prevent spoilage. A couple feet of spoiled grain near the surface amounts to a huge loss. Drainage is of critical importance to the success of any grain storage.

The ground piling surface of an outdoor pile needs to be prepared to prevent moisture from reaching the grain. The storage floor should be higher than the surrounding ground to minimize moisture transfer through the soil into the grain. The ground surface should be crowned so any moisture that does get into the pile drains to the exterior part of the pile. The ground surface needs to be a prepared surface including a low permeability surface. This may include using lime, fly ash, cement, or asphalt to make the surface. The bottom surface is a critical part of successful short-term grain storage.

Grain should be cooled with aeration to reduce the potential for insect infestations. Insect insects are dormant below about 50°`F. Cooling grain as outdoor temperatures cool also will reduce moisture migration and the potential for condensation.

Source:  Kenneth Hellevang – NDSU Extension Ag Systems Engineer

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