Storing Grain Outside This Fall? Keep It Dry & Cool
If crop output projections reach fruition this fall, there could be a lot of corn and soybeans stored in places where it normally isn't.
There are a lot of temporary and alternative storage options, but keeping that grain in good shape becomes more of a challenge when it's stored somewhere other than a grain bin, making attention to temperature and moisture of that grain a much higher priority, says South Dakota State University Extension plant pathologist Bob Fanning.
Fanning and North Dakota State University Extension engineer Ken Hellevang recommend making moisture control the top priority in grain stored on the ground, in flat-floor buildings or in poly bags.
"Grain can be stored in many types of facilities, but all storage options should keep the grain dry and provide adequate aeration to control grain temperature," Fanning says in a university report. "Grain must be dry and cool when placed into alternative storage. Aeration to control grain temperature is a critical part of any storage method, but it is not feasible to provide adequate airflow quantity and uniformity to dry grain in alternative storage."
A critical first step in putting grain away in alternative storage after harvest is getting it to the right temperature. That will affect drying capacity and overall grain quality well beyond the fall. Get it cooled to the right temperature, and make sure your storage system can keep grain uniformly dry and cool.
"If grain needs to be dried, it should be cooled to near average outdoor temperature before going in alternative storage. It is generally not feasible to provide enough uniform airflow to cool grain in these facilities," Fanning says. "Buildings that are not designed for grain storage can incur significant damage if grain is allowed to build up against the walls. Ensuring that a building can withstand the forces of grain is a complex engineering problem. Building failure can result in both a damaged building and grain that is exposed to the elements and subject to going out of condition."
Moisture concerns don't go away when you put your grain away in poly bag systems, which have grown in popularity around corn and soybean country in recent years with large fall crops. They keep grain clean but can allow moisture problems to become even more severe in the absence of good airflow. This makes drydown and storage at the right temperature immensely important with these storage systems.
"Poly bags are a good storage option, but current knowledge says they do 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 type and outdoor temperatures," Fanning says in a university report. "Heating will occur if the grain exceeds safe storage moisture content. Because the grain cannot be aerated to control heating of damp grain, bagging damp grain is discouraged. The average temperature of dry grain will follow the average outdoor temperature."
Any such system should be placed carefully; Fanning says an "elevated, well-drained location" is best for these plastic storage systems. Place the bags in a north-south direction so they receive even heating from the sun. Failing to do so can cause even more moisture issues, as "sunshine on just one side of the bag heats that side and can lead to moisture accumulation in the grain on the cool side of the bag," Fanning says. And, try to keep wildlife away from the poly bags so you don't wind up with punctured bags that allow even more moisture into the grain.
Sometimes, piling grain outside is the easiest temporary solution, but be wary of precipitation. Fanning says for every inch of rain falling on a 1-foot layer of corn stored exposed outdoors, the grain's moisture content rises by 9%. But, even if that grain is covered, your moisture worries don't end.
"Grain covers can reduce damage from precipitation, but they need to be held in place, typically by a combination of restraining straps and suction from an aeration system. The aeration system should be designed and sized to adequately cool the grain as the outside air temperature drops, and to provide suction to help hold down the grain cover," Fanning says. "For suction to develop, adequate to hold the grain cover down, the amount of open area for intake air would need to be limited."
Your potential for moisture damage in grain stored temporarily outside declines as temperatures decrease; Fanning says the potential time you can leave grain stored outside doubles for every 10-degree cut in grain temperature.
Finally, make sure the ground on which you're storing that grain -- whether in a poly bag, temporary structure, or on the ground itself -- is well-drained. Land that doesn't drain well can allow moisture to seep into the grain from the ground up, and that can cause deterioration to advance quickly. Consider taking steps to decrease how porous and permeable that ground is.
"Drainage is of critical importance to the success of any grain storage, but particularly when grain is piled on the ground. The ground surface of an outdoor pile needs to be prepared to prevent moisture from reaching the grain. The ground surface where the grain will be piled should be crowned so any moisture that does get into the pile drains to the exterior rather than creating a wet pocket that leads to grain deterioration," Fanning says. "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."