Flood-soaked grain or hay is almost certain to be contaminated, making it unfit for use as food or feed.  This summary describes regulatory considerations and recommended actions for management of agricultural grains and forages deemed unusable for food or feed following flooding.

Regulatory Considerations.

The Nebraska Department of Environmental Quality (NDEQ) recognizes in NDEQ Guidance Document 11-023 that flood-soaked grain or hay is almost certain to be contaminated, making it unfit for use as food or feed. Therefore, the NDEQ has historically allowed spoiled grain or hay to be land-applied to agricultural fields, with consideration for the nature of contamination or spoilage, amount of material affected, application field topography, proximity to neighbors, etc. Flood-damaged grain and hay has been demonstrated to be a danger to wildlife. As a result, the department recommends land application of flood damaged grain or hay to be disked into the soil within 24 hours of application. For additional information on NDEQ considerations, see “Flood Damaged Grain & Hay Disposal”¹.

Time is of the Essence.

1. Flood soaked grains and feeds will begin to heat and mold very quickly, making spoilage likely and spontaneous combustion of hays a possibility. The following guidance applies to water damaged feeds that are not salvageable:
2. Remove flooded grain from bins and stack in a well-drained location away from farm facilities. If possible, separate wet and dry grain and store separately.Wet forages and hay that are no longer submerged in water can begin to generate heat within hours due to microbial activity. It is important to move these away from farm facilities and monitor the temperature of forage piles. Farmers need to be aware of the risk of sudden flair ups in stockpiled hay and forage.  Don’t get too close to these stockpiles and allow room for escape routes. If already smoking, stay away because opening the pile and adding oxygen will almost certainly result in fire. If the temperature inside the pile approaches 150°F, the feed is composting and should be monitored closely. At 170°F, material may begin to smolder or catch fire.² 
3. A pile that exceeds 150°F should be mixed with a bucket loader to cool the interior of the pile. Be aware that temperatures will again begin to rise following mixing, so monitoring should continue and piles should be mixed whenever high temperatures are detected.
4. If field conditions will hinder access for land application of these materials for several days or more, monitoring and mixing of the pile should continue. The heating cycles, if allowed to continue, should eventually generate compost that can be safely stored until land application is possible. Instructions for compost pile establishment follow below. When the material no longer generates heat, it is a sign that the composting process is complete (i.e. no food remains for the microbes) or that the material has dried below about 40%. If the material dries out prior to fully composting, there may still be a risk to wildlife that consume the material following field application.
5. Storage bins containing flood-soaked grains will eventually need to be inspected for possible damage due to grain swelling, and damage to electrical motors and controls. Grain swelling may cause bolts to shear, doors to misalign, or caulked seals to show signs of stretching.

[Note: The temperature inside piles can be checked by driving a pointed pipe into the pile and lowering a thermometer inside the pipe. The thermometer should be left in place for about 20 minutes to allow the temperature reading to stabilize. Alternatively, digging into the innermost layer of the pile with a spade or bucket loader to check for smoldering material or ash can reveal if dangerously high temperatures are present.] ²

Composting 

Composting may reduce the potential for livestock and wildlife to consume the contaminated grain and limit their exposure to potential toxins. It should also reduce the potential for germination of grain seeds following land application and the potential for volunteer corn in fields.

To actively compost the material, pile the wet feedstuffs in windrows four to six feet high.  Smaller windrow can reduce the risk of piles over-heating and spontaneous combustion.   Leave adequate space between windrows to provide access for a bucket loader to turn the piles. It is desirable to cover wet grain with damaged hay or other forage or residue.

As noted in the previous section, closely monitoring pile temperatures is essential to detect and manage excessive heating that could generate a fire. Good compost is achieved when temperature peaks between 140 and 160°F Checking pile temperatures regularly and maintaining a water source nearby to suppress smoldering or burning material are advisable.

Burning May Be an Option

The NDEQ guidance¹ for flood damaged grains and hay suggests that burning might be a preferable method for disposal of flood-damaged foodstuffs. According to the NDEQ, open burning of these materials can be conducted without an air permit provided that the material is burned on the same site where it was damaged by flooding and no other debris or waste is combined with the grain and/or forages during burning. It is advisable, however, that the local fire department be contacted to secure a burn permit. Burning these materials may require careful monitoring over an extended period of time to ensure the fire is well-controlled and may produce significant smoke, which could generate nuisance complaints. Notifying neighbors prior to conducting disposal of feedstuffs in this way is recommended.

Land Application of Flood Soaked Grains/Forages 

If grain is spoiled but not capable of causing an infectious disease to humans (e.g. contaminated with human septage or sewage), then it may be either sent to a permitted municipal solid waste landfill or land applied. If the grain is applied to the land at an appropriate agronomic rate, prior approval from the NDEQ for land application of this material is NOT required. However, notifying NDEQ of your plans for land application is encouraged.²

An agronomic application rate should be based upon nitrogen. Not all nitrogen in the flood-soaked feed would be available in the first year following application. If we assumed 50% availability, application rates shown in Table 1 would likely be a maximum acceptable rate for a typical rainfed field averaging 160 bushels/acre and an irrigated field average 225 bushels/acre. Table 1 includes application rate estimates for feed at both 30% and 50% moisture, and for corn silage at 70% moisture.

Because the moisture content of the feedstuff impacts your final application rate, if the table does not represent the moisture content of a material being considered for land application, an application rate estimate can be calculated by dividing the “Tons of Dry Matter Per Acre” value in the table for that feedstuff by the fraction dry matter (or 1 – fraction moisture). As an example, for corn at 65% moisture content, divide 4.3 tons DM/ac by (1 – 0.65) to arrive at an application rate of 12.3 tons/ac).

Table 1.  Maximum acceptable land application rates for flood-soaked feedstuffs applied at a nitrogen-based agronomic rate (assuming 50% availability of N in first year)^a.

^a Assumes that 60 lbs N/acre is applied pre-plant as commercial fertilizer to meet early season crop N requirements.

^b 130 lb N application rate would meet needs of dry land corn yielding 160 bu/ac following soybeans in medium texture soil. 

^c 180 lb N application rate would meet needs of irrigated corn yielding 225 bu/ac following soybeans in medium texture soil.

Additional considerations when land applying flood-soaked feeds include the following:

• An in-season N assessment is recommended due to low predictability of applied organic N availability (50% assumption is likely high). Additional N application may be warranted and an option should be available for side-dressing corn.
• Incorporation of land-applied feedstuffs is recommended to minimize risks to wildlife from toxins in the grains. A moldboard plow or other aggressive tillage practice may be necessary to completely bury grains. Flood damaged grains can be particularly dangerous to bird wildlife. Composting grain before land applying should reduce palatability and risk of consumption.
• Volunteer plant growth from land-applied grain is likely. If corn has herbicide tolerant traits, controlling volunteer plants will present unique challenges. Composting of grains should reduce germination of grain seeds. For additional information on controlling volunteer corn, please review:

Control of Volunteer Corn in Soybean and Corn

Volunteer Corn in Soybean: Impact and Management

Control of Glyphosate-Resistant Volunteer Corn in Liberty Link Soybean

• If flood-soaked corn has herbicide tolerant traits, it should NOT be applied to fields that will be used for human food production (e.g. popcorn production) or seed grain production in the following growing season.

 Recordkeeping Recommendations

Document flood damaged grains and forages with written records summarizing amounts of feedstuffs damaged and dates of flooding. Time-dated photos can be particularly valuable.

When land-applied, record the number of loads hauled (or scale records, if available), area covered by land application, and timing. Again, time-dated photographs are valuable. An estimate of moisture content of the grain or hay when land applied is also desirable for document application at an agronomic rate.  If feedstuffs are incorporated into the soil, photographic documentation would be desirable.

Recovering Dry Grains in Flooded Bins

Any dry grain should be inspected, checked for moisture content, and possibly considered for re-use with animals. If the grain can be salvaged for use by animals, Ken Hellevang, agricultural engineer for North Dakota State University¹ recommends:

• If the grain depth is less than 6 feet, use a natural-air bin drying system with a perforated floor and a high-capacity drying fan. Verify that the air is coming through the grain. Supplemental heat can be used to speed drying, but do not raise the air temperature more than 10 or 15 degrees F.
• If a dryer is not available, spread the grain in as dry a place as possible. Don't pile it any higher than 6 inches. Stir it daily to prevent overheating and to speed drying. Watch for and remove molded grains.
• Wet grain can be ensiled if it is intended for feed and the moisture content is between 25 and 35 percent. If using a conventional silo, see your county Extension agent about treating the grain with propionic acid to prevent mold.

Lastly, Dr. Hellevang and his co-authors of a North Dakota State University publication² warn, “Do not feed flood-damaged grains until they are tested for mycotoxins, toxic substances produced by fungi. Ask your county Extension agent for locations of testing laboratories. Even if the feed is deemed safe to use, watch animals carefully for signs of illness.”

References: The authors are indebted to the authors of two references listed below that served as a foundation for multiple topics presented.

1. NDEQ. 2016. Flood Damaged Grain & Hay Disposal, Guidance Document 11-023, rev. November, 2016. http://deq.ne.gov/publica.nsf/pages/11-023
2. Hellevang, K., H. Kandel, C. Stoltenow and G. Lardy. 2010. Salvaging Stored Wet Feed and Grain. North Dakota State University. https://www.ag.ndsu.edu/flood/farm-ranch/salvaging-stored-wet-feed-and-grain.