Managing Flood-Damaged Crops

Recent high water has caused much flooding in lowland corn and soybean fields. This has raised many questions about how to manage these crops. Based on experiences in a recent pre-harvest flood in Vermont, here's what we would expect when crops are subjected to these conditions:

--Affected fields will contain a lot of debris and plants will have a lot of soil on them.

--Conditions will be dusty and dirty during harvest.

--Most farmers in the Vermont flood experienced extra costs from wear on shear bars, knives and bearings. The silage they made from flood damaged fields ranged from acceptable to black or rotten and some farmers reported decreased milk production.

If your fields sustained flooding, here are recommendations and observations that may help in making harvesting and marketing decisions:

Corn for Silage

• Corn destined for silage would be more at risk for fungal and bacterial contamination. Take steps to promote good fermentation, such as heavy inoculation and extra packing of the silos. A good fermentation will kill many pathogens in the silage.
• Target the least affected fields for silage and harvest above the silt line to avoid soil contamination.
• Avoid chopping corn for silage that has considerable dirt or silt on it.
• Segregate any corn chopped for silage so that it can be evaluated before feeding. Forage should be tested before feeding, paying particular attention to energy, ash and mycotoxins.
• Silage and high moisture corn from these fields should be evaluated at feedout and animal health should be closely monitored. Soil contamination alone may not be a serious animal health factor, but contamination from manure, sewage treatment plants and other chemicals is unknown and could vary from one situation to another.

Corn for Grain

• Harvesting for grain is likely a better option than for silage where flooding has occurred.
• Combine air filters likely will need to be changed more frequently. Operators should take steps to avoid breathing the dust.
• Harvest when the fodder is dry to help limit the dirt in the grain. Monitor the dirt in the corn coming into the bin and avoid the worst sections of fields.
• Harvesting high-moisture corn at the drier range of acceptable levels could improve the ability to clean dirt from the corn.
• The expected quality of grain is uncertain and should be monitored. The potential for crop contamination by flood waters could affect the marketability of grain and silage. Check with your county Penn State Cooperative Extension office or the Pennsylvania Department of Agriculture for more information on marketability as it becomes available.
• Monitor for sprouting. Some river bottom fields are prone to bird damage and often have some sprouting risk. The flood may exacerbate the problem. Try to adjust the combine to remove most of the sprouted grain.
• Monitor for molds. Corn from flood-damaged fields should be evaluated for grain quality and kept separate if there are indications of molds. Mold and mycotoxin levels can be determined by most feed testing laboratories and used as guidance in marketing.
• The risk of molds and sprouting is likely a function of the exposure to the water and stage of growth. In some areas along the Susquehanna River, the corn was under water for about 36 hours. Corn that was under water will have an increased risk for molds and bacterial rotting. This may be more pronounced in corn that was already drying down (<40% grain moisture) and then took on moisture during the flood.
• Monitor for bacterial stalk rots. Fields that remained flooded for more than 12 hours are most at risk for stalk rots.
• The crop may mature more rapidly under these conditions, since corn that has been stressed when near maturity often seems to dry down fast.
• If the grain is deemed unfit for animal use, then it will be necessary to pursue crop insurance claims. If producers expect a claim, they should consult with an adjuster prior to harvest.

Other Crops

• Soybean crops likely will experience increased harvest losses and increased machinery problems during harvest. Many soybeans may be impossible to harvest due to lodging and debris. Monitor grain quality prior to harvest.
• Avoid pasturing or harvesting silt laden forage crops if at all possible.

In summary, flood-damaged crops are at risk for quality and harvest losses, but by monitoring and managing carefully, we may be able to salvage some of them.

Information provided by Greg Roth, Glen Cauffman, Erick DeWolf, Jud Heinrichs, David Wolfgang and Craig Altemose.

For More information please visit:

Penn State Corn & Soybean Management
FDA - Moisture Damaged Grain (section 675.300)
Iowa State - Guidance on Flood Water-Damaged Grain

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