Documentation
U.S. farmers have adopted genetically engineered (GE) crops
widely since their commercial introduction in 1996, notwithstanding
uncertainty about consumer acceptance and economic and
environmental impacts. In terms of share of planted acres, soybeans
and cotton have been the most widely adopted GE crops in the U.S.,
followed by corn.
The tables in this product provide data obtained by USDA's
National Agricultural Statistics Service (NASS) in the June
Agricultural Survey for 2000 through 2012.
Randomly selected farmers across the United States were asked if
they planted corn, soybeans, or upland cotton seed that, through
biotechnology, is resistant to herbicides, insects, or both.
Conventionally bred herbicide-tolerant varieties were excluded.
"Stacked" gene varieties are those containing GE traits for both
herbicide tolerance (HT) and insect resistance (Bt).
According to NASS, the States published in these tables
represent 81-86 percent of all corn planted acres, 87-90 percent of
all soybean planted acres, and 81-93 percent of all upland cotton
planted acres (depending on the year).
The acreage estimates are subject to sampling variability
because all operations planting GE varieties are not included in
the sample. The variability for the 48 corn States, calculated by
NASS using the relative standard error at the U.S. level, is
0.3-1.8 percent for all GE varieties (depending on the year),
1.6-2.5 percent for insect-resistant (Bt)-only varieties, 1.6-3.8
percent for herbicide-tolerant-only varieties, and 1.0-10.8 percent
for stacked gene varieties. Variability for the 31 soybean States
is 0.3-0.8 percent for herbicide-tolerant varieties, depending on
the year. Variability for the 17 upland cotton States is 0.6-2.2
percent for all GE varieties, 4.6-10.6 percent for insect-resistant
(Bt)-only varieties, 2.6-6.6 percent for herbicide-tolerant-only
varieties, and 2.0-4.2 percent for stacked gene varieties.
Data Sources
Three USDA surveys provide agricultural production data for the
adoption of genetically engineered (GE) corn, cotton, and soybean
varieties:
- Agricultural Resource Management Survey (ARMS) (for
1996-98)
- Objective Yield Survey (for 1999)
- June Agricultural Survey (for 2000 and beyond)
1996-98 Data - The NASS/ERS ARMS Surveys
The ARMS
surveys developed by the Economic Research Service (ERS) and
the National Agricultural Statistics Service (NASS) of USDA are
conducted annually starting from 1996. These surveys link data on
the resources used in agricultural production to data on use of
technologies (including the use of genetically engineered crops),
other management techniques, chemical use, yields, and farm
financial/economic conditions for selected field crops. Each survey
includes three phases: screening, obtaining production practices
and cost data, and obtaining financial information. The number of
States covered by the surveys varies by crop and year, but each
survey includes States that account for between 79 and 96 percent
of U.S. acreage in the specified crop.
1999 Data - The NASS Objective Yield Survey
The 1999 adoption data are based on responses from the seed
variety questions on the 1999 Objective Yield and Farm Operator
Survey conducted between September and October to gather
information on expected yields. The information was published in
October 1999 in the NASS report Crop Production. The
Objective Yield Surveys (OYS) for corn, soybeans, and cotton were
conducted in the major producing States that account for between 61
and 71 percent of the U.S. production. NASS conducts objective
yield surveys in major corn, soybean, and upland cotton producing
States each year. Randomly selected plots in corn (for grain),
soybean, and upland cotton fields are visited monthly from August
through harvest to obtain specific counts and measurements. The
farm operator survey was conducted primarily by telephone with some
use of mail and personal interviewers. Herbicide-tolerant varieties
include those developed using both biotechnology and conventional
breeding techniques. Insect resistant varieties include those
containing Bt. These data are intended to show trends in production
practices but are not official estimates of USDA's Agricultural
Statistics Board.
2000-12 Data - The NASS June Agricultural
Survey
The 2000-12 adoption data were collected as part of the June
Agricultural Survey that NASS conducts during the first 2 weeks of
June and publishes at the end of June in the NASS report Acreage. Enumerators
conducting the area survey contact all farmers having operations
within the sampled segments of land and account for their
operations. Farmers in the list survey sample are contacted by
mail, telephone, or personal interview to obtain information on
their operations. Responses from the list sample, plus data from
operations that were not on the list to be sampled, are combined to
provide another estimate of planted and harvested acres. Regarding
GE crops, randomly selected farmers across the United States were
asked during the first 2 weeks of June if they planted seed that,
through biotechnology, was resistant to herbicides, insects, or
both. Unlike previous surveys, herbicide-tolerant varieties in this
survey include only those developed using biotechnology.
Conventionally bred herbicide-tolerant varieties were excluded from
the survey. Insect-resistant varieties include only those
containing Bt. Stacked gene varieties include those containing
genetically engineered traits for both herbicide and insect
resistance.
Comparability Across Surveys
Data from the three different USDA surveys are not directly
comparable because none of the surveys were specifically designed
to collect data on GE varieties. Rather, questions on adoption of
GE crops were added to different USDA survey instruments whose main
objective was not measuring the extent of adoption of these crops.
As a consequence, survey coverage among the three types of surveys
often differs. There are also some differences in the base acreage
used to calculate the percentage of adoption (unlike the other
surveys, which report adoption rates relative to planted acres, the
Objective Yield Survey reported the adoption rates relative to
harvested acres), and the questions related to GE crop adoption are
not identical in different surveys. See the publication Adoption of Bioengineered
Crops for more detail about the different surveys. In
particular, adoption data for 1996-99 include herbicide-tolerant
corn and soybeans obtained using traditional breeding methods
(non-GE). The more recent data (2000-12), on the other hand,
excluded these varieties.