Across the nation, plantings of genetically-engineered, or transgenic,
crops have increased rapidly in recent years, primarily in soybean, cotton
and corn. While many farmers see the use of such crops as beneficial
for controlling pests, other farmers, particularly organic farmers and
farmers with markets for non-GMO products, are concerned about transgenic
crops because of the potential for contamination of their crops. In addition,
concern about genetically-modified organisms (GMOs) is present in Vermont
communities, as indicated by the nearly 70 Vermont towns that have considered
and passed resolutions regarding their use. Pro, con, or neutral,
Vermonters are quite aware of this controversial issue. The University
of Vermont’s Center for Rural Studies 2002 Vermonter Poll found that 82
percent of respondents had heard of GMOs.
Although the US Food and Drug Administration has determined transgenic
crops to be "substantially equivalent" to non-GMO foods, the issue will
be debated for some time to come and ultimately be decided by consumers
in the marketplace, federal and state regulators, and perhaps, the courts.
Meanwhile, there are no regulations or official recommendations in
place to guide farmers on how to strike a balance between the right to
farm as they see fit and the desire to avoid conflict with their neighbors.
So, in the Vermont spirit of tolerance, accommodation and protection of
individual rights we offer the following strategies as a common-sense,
pro-active approach to keeping transgenic seeds, plants and pollen where
they are wanted -- and preventing them from going where they are not.
There’s room in Vermont for a wide spectrum of farmers. But, as a
farmer, you have a responsibility to maintain open communication with neighbors,
especially if you plan to plant transgenic crops this spring or if you
are an organic producer who faces significant crop devaluation through
contamination with GMOs.
In Vermont, transgenic field corn is of particular concern because
it cross pollinates and has pollen that can be airborne for some distance.
Although soybeans are primarily self-pollinating, they also warrant attention
because pollen can go where not intended due to bees and other insects.
Soon, transgenic varieties of alfalfa and other crops may be available,
so the need for careful planning and good communication will only increase.
Talk to Your Neighbors
Producers who plan on planting transgenic crops are encouraged to
speak to their farm neighbors about their plans. In addition, organic
producers, or those who have concerns about transgenic crop plantings adjacent
to their farm properties, are encouraged to talk to their farm neighbors
about their need to meet organic standards. To start with, good communication
can determine if there is any reason for concern – maybe no transgenic
crops are being planted, or maybe there are no neighbor concerns.
If there are concerns, efforts can be made to prevent contamination by
selecting fields away from neighboring farms for planting of transgenic
crops and/or for planting of organic crops at risk of contamination, and/or
by planting of ‘buffer strips on one or both neighboring farms.
Know What You Plant
Farmers that do not want to plant transgenic crops should take care
to order the appropriate varieties. Transgenic seed orders usually require
a signed contract, but farmers should still inspect the seed bag labels
before planting to make sure they did not accidentally get a transgenic
variety. If unsure of what you are about to plant, contact your seed salesperson.
Shared Equipment Can Move Seed
Trucks, bins, planters, combines, etc. can have residual seeds in
them. If you share equipment with other farms, be aware that you may get
some of their seed onto your farm. While some equipment can be pretty thoroughly
cleaned out, some cannot. Combines in particular are almost impossible
to get absolutely clean.
Use Rotation Plans to Separate Crops
If farmer A is organic and farmer B is planting transgenic corn, but both grow mixed alfalfa hay, the 2 farms could co-ordinate their rotation
to minimize the threat of transgenic corn pollen drift. In other words,
when farmer A’s organic hay is by their shared border, farmer B’s transgenic
corn could be grown on the other side of B’s farm, and when organic corn
is by the border, conventional hay could be on the other side. This will
work at least until we have to deal with transgenic alfalfa.
Use Crop Maturity Dates to Avoid Cross Pollination
If a farmer is growing long-season transgenic field corn, a neighboring
organic sweet corn grower could try to avoid cross-pollination by planting
Use Physical Distance to Separate Crops
The crops to be grown in adjacent fields are of highest concern
for cross contamination. While the majority of corn pollen falls very near
the edge of a cornfield it’s the small amount that remains airborne that
we have to be concerned about, particularly when environmental conditions
are conducive to the movement of pollen. A localized strong wind during
tasseling may carry corn pollen quite far – research has documented corn
pollen drift of many miles.
If a transgenic corn crop is to be grown in a field next to an organic
field corn crop, for instance, implementing adequate isolation distances
or using an appropriate number of border rows should be considered.
While there’s no absolute guarantee that cross contamination will not occur,
the likelihood that it will can be greatly reduced by following best-practices
hybrid seed corn isolation recommendations. If fields are closer than the
minimum isolation distance, then border rows can be used to protect against
cross-pollination (see Table below).
We reviewed several crop improvement association isolation recommendations
for production of hybrid corn and/or identity preservation. These range
from a minimum of 410 feet separation to 610 feet between plantings of
different types of corn.
Table 1. Minimum number of border rows of isolation for hybrid corn
production. Indiana Crop Improvement Association standards.
Field size up to 20 acres
Field size greater than 20 acres
Min. distance (ft)
Number of Border
Number of Border
Martens, M-H. What can organic farmers do to reduce contamination
from genetically modified crops? Mid-winter 2000 NOFA-NY Newsletter.
Robin Palmer. January 20, 2002. Vermont Voting on GE
Bans & Labeling Across the State, Seeds of discontent: Petition drive
aims to make gene-altered crops. Times Argus, Barre-Montpelier, Vermont.
Stein, Jeff, Director of Regulatory Affairs, Syngenta. From
presentation at UVM, 3/28/02.