Temporary Grain Storage Solutions
If you are caught short on storage and can’t get a bin put up prior to harvest, there is another option besides taking grain to the elevator and suffering market-low prices.
You can successfully hold grain outdoors for a couple of months until a new bin is ready. The key is creating a temporary holding area that minimizes quality losses. “Sufficiently dry corn (15% moisture or less) stored in piles only during cooler fall and winter weather does not usually need to be covered and aerated,” says Dirk Maier of Kansas State University. “It’s when grain is stored into the following spring and summer that tarp covers are used and provisions need to be made for aeration."
Thus, you will want to wait to pile grain outdoors until the last of the harvest. That crop will have dried down to 15% or less in the field and will be cooler (50°F. to 60°F. is ideal). By waiting until the end of harvest, the grain won’t be exposed as long to rain while a new bin is finished.
Optional indoor storage spaces
Before resorting to outdoor piling, consider potential spaces in farmstead buildings. “Existing buildings can be used to store grain for three months if the grain is not piled against the outside walls,” says Timothy Herrman of Kansas State University. Or, “with modifications, grain may be piled up to 4 feet deep along the walls for temporary storage. In the final analysis, the most economical answer for strictly short-term storage is to pile grain on the floor and peak the pile as much as possible.”
Another storage alternative is to invest in a grain bagging system. A 10-foot-diameter bag, for example, can store about 60 bushels per foot. If grain is put in a bag, it should be dry and cool, advises Ken Hellevang, of North Dakota State University.
The cost of a single-use storage bag is around 5¢ to 7¢ per bushel plus loading and unloading equipment, which can cost between $50,000 and $165,000.
Estimating storage space
Outdoor storage is not without cost, however. To avoid excessive spoilage losses, you need to invest in site preparation. Good drainage and the way a pad is created are crucial to success, Hellevang points out.
The first step is estimating how much area you need to hold crop overflow. A detailed area estimation table can be found on page 6 of the Kansas State University publication Emergency Storage of Grain: Outdoor Piling (publication MF-2363).
When sizing up space, include area for conveying equipment and maneuvering trucks and trailers. Trucks need ¼ to ½ acre (or a 130-foot diameter) to turn around.
Creating the pad
After the storage size is calculated, select a location that is well drained. The storage pad itself should be crowned under the pile, Hellevang advises. A 1% to 2% slope offers good drainage. Create the pad by mixing lime, fly ash, or cement in the soil prior to compacting it to reduce water permeability. Technically, the amount of compression necessary for a good pad should approach 95% of the standard proctor density. This value can be measured by the engineering firm using a density gauge.
Hellevang also advises placing 6-mil plastic on the surface to prevent ground moisture from wetting grain.
What about aeration?
If you are concerned about the center of the pile heating up, you can locate ventilation ducts so they’re positioned parallel to the long axis of a rectangular pile. Positioning ducting this way cools the pile’s core and also makes it easier to remove the corn later. To aerate, use low-velocity fans that provide approximately 0.1 cubic foot of air per minute per bushel for dry grain (under 15%).
Ducts placed at the front and back ends of the pile should extend approximately 70 feet beyond the grain. For large piles (length of the long axis is greater than 200 feet), ventilation of the pile core may be accomplished by running ducts in from the sides and intersecting at the center of an 80-foot duct running parallel to the long axis, thus forming a T-shape.
Achieve maximum slope
Finally, when building the pile, keep the drop distance from the spout of the auger to the pile at a minimum. Doing so will achieve maximum slope. The maximum angle of repose and pile height occurs when grain rolls down the side of the pile.
You may want to cover the pile with plastic tarps if the fall is wet and if the pile is left exposed for several months. Hellevang says just 1 inch of rainfall evenly distributed across a pile could potentially rewet the top 12 inches of grain to near 9% moisture.