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Extension > Agriculture > Crops > Small Grains > Harvest > Managing flooded grain bins

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Managing flooded grain bins

Bill Wilcke, Extension Engineer UM Biosystems and Agricultural Engineering Dept

Grain bins exposed to flood waters are likely to have sustained damage and some grain loss can be expected. It might, however, be possible to repair bins to salvage at least part of the grain.

Water does not "wick" very far in whole grain, so it is likely that grain above the water line is still in good condition. It might even be possible to salvage grain that was submerged in flood waters, but quick action will be required to prevent spoilage of this very wet grain.

Actions necessary for salvaging flood-damaged grain depend on the extent of damage to both bin and grain, so the first step is to inspect the bin, including unloading and aeration equipment, and the stored grain. Then, contact your insurance company or disaster relief agency as soon as possible to find out what you need to do to document losses.

Here are answers to some potential questions about flooded grain bins:

How much time does it take for wet grain to spoil?

The rate of spoilage for wet grain depends on its moisture content and temperature. Grain that was submerged for more than a few days will have a moisture content of about 30 to 50%. At warm spring and summer temperatures, grain this wet will become moldy in a few days.

If the bin was only partly submerged, can dry grain be left on top of the wet grain?

Dry grain will be relatively safe for a few weeks, but it would be best to separate it from the wet grain as soon as you can because the wet grain will begin to spoil in a few days and generate mold, heat, and odors that could reduce the quality of the dry grain above it. Try to unload the dry grain without mixing it with the wet. Using a vacuum-type grain conveyor to suck the dry grain out the top of the bin might be the best way to do this. Consider selling the dry grain, moving it to an undamaged storage bin at your place or a neighbor's place, or temporarily storing it in a machine shed or other building modified for grain storage.

What can be done with grain that was exposed to flood waters?

If the grain is not contaminated with excessive silt, bacteria, fuel, or chemicals, (grain that is in contact with flood water is likely to be contaminated) it might be possible for you or a neighbor to feed wet grain directly to livestock (check regulations first). Remember that wet grain will spoil quickly; if it can't be fed in a few days, consider adding a grain preservative to extend shelf life. If the grain moisture is between 25 and 35%, consider ensiling it in an upright silo, plastic-covered horizontal silo, or plastic silage bag. Beware that grain in ruptured bins could contain bolts, bin hardware, or other debris that should be separated out (consider using grain cleaners and/or magnets) before the grain is fed.

Another option is to dry the wet grain in a gas-fired dryer. Energy costs for on-farm drying will be high. Be aware that after drying, grain should be cooled to less than 60 degrees Fahrenheit for safe storage; it will be difficult to find weather cool enough to adequately cool grain that is dried during summer months.

If you can remove the dry grain from the top of the bin and can get the fan going, you might be able to use unheated air to dry wet grain in bins equipped with full-perforated floors and large drying fans. Chances of success for unheated air drying decrease as grain moisture, outside temperature, and grain depth increase. If the grain is much wetter than 20% moisture, don't use this drying method for more than about six feet of grain.

Under certain conditions, grain molds can produce mycotoxins that can cause animal feed refusal, health problems, or even death. Since beef cattle (except for breeding stock), are somewhat less sensitive to molds and mycotoxins than other animals, feeding suspect grain to beef cattle as part of a mixed ration would be safer than feeding to other animals. If grain develops a lot of visible mold, test for mycotoxins before feeding it or spending money to dry it. Grain that is badly damaged by mold or has high levels of mycotoxins or contaminants should probably be discarded.

How should the bin be unloaded?

You probably won't be able to remove grain through the bin's unloading system. If electric motors on the unloading system have been under water, it is best not to start them until they have been cleaned, dried, and lubricated. And very wet grain probably won't flow out of the bottom-unloading sump anyway. Consider using a vacuum-type grain conveyor to suck the grain out of the top of the bin.

If the water line was below the level of the side door on the bin, it might also be possible to insert an auger into the dry grain through a small opening in the side door. Make sure the auger extends to near the center of the bin, however, because unloading a bin from one side creates uneven sidewall pressures that can damage the bin.

What kind of bin damage is likely in flood situations?

It is not unusual to find structural damage to bins after floods. Because grain swells when it absorbs moisture, it exerts a great deal of pressure on the inside of bin walls, often resulting in stretched bolt holes, broken bolts, and torn bin sheets. Sometimes, bins are knocked off their foundations or dented by the pressure of moving water or by impacts from floating debris. Rapidly moving water can also cause erosion around foundations.

Drying, aeration, and unloading equipment on bins are likely to be inoperable immediately after floods. In many cases, however, electric motors and controls, and gas burners will work again after they are cleaned and dried. Don't try to start electric motors until they have been cleaned and dried or they might burn out. You should also clean mud and debris off of fan blades to prevent imbalances that might lead to bearing damage. Bearings might need to be dried, relubricated, or replaced. In many cases, aeration ducts and areas under full-perforated floors will contain mud and saturated grain fines. Clean these areas before the bin is filled again.

Companies that work on grain bins are likely to be quite busy after widespread flooding, so if repair work is needed, try to line up a contractor as soon as possible to get bins repaired before next harvest.

Are problems likely if water surrounded the bin foundation, but didn't actually flow into the grains?

If the bin has an elevated, full-perforated floor, and the water level remained below the floor, the grain is probably fine. You might still need to check for erosion around the foundation, damage to the fan and unloading system, and mud accumulation under the floor.

If grain rests directly on a concrete floor, it is possible that water moved up through small cracks and pores and wet a few inches of grain next to the floor. It is also possible that in-floor aeration ducts are full of water and mud and that the fan and unloading system have been damaged by water. If you can get the aeration system to work, attempt to dry the layer of wet grain by aerating it. Or, if you can get the unloading system to work, consider transferring grain from one bin to another to get the layer of wet grain off the floor before it molds.

Are there safety concerns about working around flooded bins?

Possible safety hazards include electrical short circuits, gas leaks, sudden rupture of weakened bins, entrapment in flowing grain, and breathing dust and mold spores from damaged grain. Turn off gas valves and electrical power until you have a chance to clean, dry, and inspect gas and electrical systems. Work in pairs and stay out of flowing grain. And finally, wear a tight-fitting, high-quality dust mask or respirator that is designed to filter mold spores and other toxic dusts when handling flood-damaged grain.

Revised 2007

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