Flooded Crops: Food Safety and Crop Loss Issues

Many growers across the state have fields that had flooding or ponding in the wake of hurricane Irene. Questions always arise as to what effect flood waters may have on the safety of crops.  There is no easy answer. This article is a compilation of information from several sources to help growers understand how to report and seek assistance to mitigate crop losses, and how to decide what crops might be salvageable after the waters recede.

Flooding vs. ponding

Floods occur when water or runoff from surface waters such as rivers, lakes or steams overflows and runs into fields. Water from heavy rainfall that pools on the surface of saturated soils is NOT considered flooding and is therefore not bound by FDA restrictions and guidelines regarding flooded crops. If water puddles in a field due to high rainfall, the chances of contamination are minimal. 

Fields that were saturated with collected rainfall may suffer crop losses from several causes including plant death from being underwater or with roots in saturated soil, or outbreaks of plant disease.. Diseases are most likely to develop from pathogens that bloom in wet soil and warm humid air such as Fusarium, Sclerotinia white mold, black rot of squash, or Phytophthora capsici, and where crops are in contact with soil.

Flood waters are more serious because they are likely to contain contaminants. Contaminants may include: raw sewage, raw manure, agricultural or industrial chemicals, heavy metals or other chemical contaminants. Microbial pathogens that could be in flood waters include bacteria, viruses, and parasites. These may come from upstream farms and rural septic systems, urban lawns, roadways, buildings and industrial sites, or overflow from municipal sewage systems.  In flooded areas in the Connecticut River Valley and in the Berkshires, the periods when flooding was at its peak were also periods when municipal water treatment plants were overflowing and releasing sewage into the rivers. Likewise, water was also flowing over fields or barnyards with livestock. Thus E. coli contamination is a real threat in any flooded areas downstream.

Reporting losses and seeking financial assistance

Before cleaning up or destroying crops in flooded fields, check with your crop insurance and/or local Farm Services Agency (FSA) representatives regarding exact documentation to certify losses, procedures for initiating claims, possible financial assistance.

Take photos of damaged field for visual documentation. Estimate crop value and degree of losses. 

Contact your county FSA office and fill out a crop loss report. This benefits your region because it helps to document the extent of damage to crops in your county which will determine eligibility for federal disaster aid.  It will benefit you by establishing what level of damage you sustained. You do not need to have crop insurance to be eligible for disaster aid should your county be eligible. The state FSA office can link you to counties: phone 413-253-4500 or find county office listings online.  USDA Farm Service Agency’s (FSA) will be submitting documentation for federal emergency assistance. One program that may become available is the Emergency Conservation Program (ECP) which provides emergency funding and technical assistance for farmers and ranchers to rehabilitate farmland damaged by natural disasters and for carrying out emergency water conservation measures in periods of severe drought.

If you have crop insurance, contact your crop insurance representative to arrange a visit from the crop adjustor to determine extent of losses. 

Contact NRCS offices if you have technical questions on soil impacts or movement and placement of sediment (below).

FDA guidelines regarding harvest

The Food and Drug Administration has issued guidelines regarding harvesting crops from flooded fields. Because of the microbial and chemical contaminants in floodwater, the U.S. Food and Drug Administration (FDA) considers crops where the edible portion has come in contact with flood waters to be ‘adulterated’ and not to be sold for human consumption.  Following FDA guidelines, growers should discard all crops that have edible portions that have come in contact with flood water.

A thirty-foot buffer (area to turn equipment) should be maintained between the crop and flood areas. To reduce the chances for cross-contamination do not drive through the flooded areas to harvest.

There may be some gray areas where growers may use their discretion.

Crops near flooded areas or those that were flooded without the edible part of the plant coming in contact with flood water (such as sweet corn or staked tomatoes -- see photo) need to be evaluated on a case by case basis. If the edible portion did not contact flood waters and can be harvested without contacting contaminated soil, then it may be considered safe, although further washing and disinfecting would be recommended.

Crops in which the edible portion develops after flood waters recede are not automatically deemed adulterated. This could include some fall vegetables that had only mild or short-term flooding and are early in their development, so that harvested portions will be growth that occurred after the flood.

If your well head was submerged, re-test your well water to make sure that only safe, potable water comes into direct contact with produce. 

Impacts on soil and field cleanup

As floodwaters recede the sediment and erosion become visible and cleanup begins. However, before going on to the fields, be sure the soil has drained and is workable; working it too wet will exacerbate compaction problems.  It is important that the sediment deposits are spread out evenly on the field before turning it under.  An inch or two is not a problem, but if sediment is 6 inches or more, should be pushed around and evenly distributed before being incorporated.  Silt can have benefits to soil – after all, flooding is why we have deep silt loams in river valleys - but it will be low in organic matter. Test soils after incorporation to determine further soil amendments that may be needed.  When sediment is moved, it should not be dumped into wetlands; this is in violation state and federal wetlands regulations. Contact your local NRCS office regarding technical assistance and possible special funding for cleaning up.

To protect the soil from further erosion, it is advisable to plant a cover crop on fields that cannot be re-planted soon with an edible crop. Cover crops can also help suppress weeds, and improve overall soil health. At this time of year (early fall) small grains such as oats, wheat or winter rye are good choices, with or without hairy vetch for adding fixed nitrogen.

--Andrew Cavanagh, Rich Bonanno, Ruth Hazzard, UMass Extension. The article above also drew on summary of information compiled by Ginger Nickerson of the UVM Extension Center for Sustainable Agriculture.  For her full article, please see https://newfarmerproject.wordpress.com/2011/08/30/reporting-flood-losses...
We also appreciate information provided by Tom Akin, NRCS State Conservationist, and Dick Burke, MA State FSA Director.