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How can I maintain the purity of my organic corn?

Answer

NOP regulations do not currently dictate the level of GMO purity present in harvested organic crops. Organic production is a process-based verification (vs. an end-product verification) so crops can have GMO contamination but still be considered certified organic. However, given tighter competition in the consumer marketplace with a slew of labels making various claims (natural, non-GMO, sustainable, etc.), end-markets for organic corn have developed more stringent purity requirements than ever before.

In general, organic corn going into the livestock feed market has a GMO contamination tolerance of anywhere from 2-5% while corn going into the human food market is often <1%. Organic corn is one of the most lucrative crops in an organic grain rotation, but raising a crop that meets marketer and consumer demand can be challenging. The vast majority of corn planted in the United States is genetically modified. Additionally, corn is a promiscuous crop, shedding viable pollen that can travel for miles to cross-contaminate organic fields separated by buffers, windbreaks, and other physical barriers.

What is an organic producer to do?

Fortunately, there are things within your control to minimize the potential of GMO contamination to your organic corn and harvest as pure a crop as possible.

First, always start with seed from a reputable source that clearly tests and labels seed for GMO contamination. If GMO testing isn’t clearly noted from your seed company, ask them for test information. While purchasing purity-guaranteed seed is not the only way to limit contamination of your harvested grain, it is a wise insurance policy. There are, additionally, corn hybrids that limit pollination from foreign pollen through traditional breeding techniques. These may also be an option, depending on your region.

Second, vary the timing of your corn’s maturity from surrounding farms. Organic corn is often planted later than conventional to take advantage of warmer soil conditions and optimum growing degree days. Planting slightly earlier hybrids for your region will stagger your crop’s pollination time from neighboring fields, limiting the potential of cross-contamination. Choosing fields with the most physical isolation is also a good option to maintain optimum purity.

If your corn fields are in close proximity to genetically modified corn, it may be wise to harvest and store the outside 16-24 rows separately even if you have appropriate buffers in place. This could potentially prevent high concentrations of cross-contaminated corn.

Third, ensure the cleanliness of all planting, harvest, and storage equipment, especially if you’re running a split operation, sharing equipment or hiring a custom operator. Depending on the test that your end market may take, it doesn’t take many contaminated kernels to result in a positive test. Run combines clean with doors open and blow out thoroughly with compressed air; especially cutting platforms, corn head, separators, grain tanks and unloading augers.

Purging equipment after a thorough cleaning with small grains or another medium can also help. Ensure all gravity wagons and trucks are swept and blown clean and store your harvested corn only in cleaned-out bins. Pay special attention to nooks and crannies like false floors, slots, slides, and doors. Careful recordkeeping of all of these processes like clean truck affidavits, field logs, etc. can help should problems arise at the time of delivery.

Finally, when it comes time to market your crop, if possible send in a representative sample first before sending a whole load. Bringing back or rerouting a contaminated load is expensive. If you do have corn that is contaminated, it may be an option to direct market it to a livestock farmer or livestock feed buyer, which often have lower standards than food-grade markets.

Posted: Oct 2018
Answer By: Matt Leavitt