Sustainable Agriculture Literature Review - Boulder County

! ! !!
"#$%&!'())!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!=+!>5?324!
Cross-Pollination
There is concern among farmers, consumers, and the organic food industry about fields
planted with GE seeds and their proximity to those planted with non-GE seeds. This
concern has stemmed from potential cross-pollination of GE and non-GE crops. Pollen
drift with GE crops has received greater attention than with non-GE crops, because
contamination by GE crops can cause an economic loss to farms using non-GE crops,
especially certified organic farms. There is no debate that cross-pollination can and does
happen in all types of agriculture. In Boulder County, some organic and conventional
farmers are concerned about the possible economic loss if GE pollen contaminates their
non-GE crops. 498 Organic crops cannot contain genetically modified organisms and
therefore would greatly lose value if cross-contamination were found in their crops. 499
The concern of pollen drift in Boulder County prompted a study to estimate and evaluate
the amount and distance of pollen drift in GE and non-GE corn. The two test sites
included one containing blue kernel color on BCPOS land and the second on an
adjacent cooperating farmer’s land with the common GE corn containing the Roundup
Ready" trait. The study concluded that a 46-meter or about 151 feet would allow a
barrier that would ensure a less than one percent chance of cross-pollination. 500 Past
field experiments on cross-pollination of corn concluded that 200m (660 feet), was
sufficient to limit cross-pollination to one percent or less. A distance of 300m could limit
cross-pollination to 0.5 percent or less. 501 A review of past experiments concluded that
levels of cross-pollination are affected by the size of the “emitting” crop and the strength
of the wind. 502
There is contention between studies on the appropriate barriers between GE crops and
other crops. Since corn pollen is much larger than pollen produced by most grasses and
is among the largest particles found in the air, it drifts to the ground quickly and does not
normally travel the distance of pollen produced by other members of the grass family.
Corn pollen may remain viable from a few hours to several days following its release and
can survive up to nine days when stored in refrigerated conditions. Under normal field
conditions, pollen is normally viable for only one to two hours. A probable reason for the
discrepancies among studies is that temperatures and humidity affect the viability of
pollen and the different conclusions among studies could be attributed to the varying
levels of temperature and humidity in the areas studied. Pollen has a reduced period of
viability for pollination in areas with high temperatures and low relative humidity. 503
!
",'"
!,342#.5#6/1!78$.%3/23$1!
9.21$#23$1!:1;.1