Introduction
The adoption of herbicide-tolerant soybeans has been particu-
larly rapid in the United States, increasing from less than 10
percent of soybean acreage in 1996, when the technology was
introduced, to nearly 70 percent in 2001 (USDA, 2001; fig.
B-1). The rapid adoption has reflected the benefits of poten-
tial increases in crop yields and savings in pest control costs
from this technology. But more importantly, herbicide-toler-
ant soybeans offer producers the simplicity and flexibility of a
weed control program that relies on one herbicide to control a
broad spectrum of weeds without crop injury or crop rotation
restrictions (Carpenter and Gianessi, 1999b). Thus, estimates
of the benefits from adopting herbicide-tolerant soybeans
and their distribution among the stakeholders require accurate
information about the technology’s farm-level impacts
on crop yields, pest control costs, and the ease of weed
control management.
Estimates of the farm-level effects differ significantly,
depending on the data source. For example, a recent study
of the distribution of benefits from biotech adoption by
Falck-Zepeda, Traxler, and Nelson assumed that adopters’
yields for 1997 herbicide-tolerant soybeans were 13.0 per-
cent higher than nonadopters in the Corn Belt based on data
from the U.S. Department of Agriculture’s Agricultural
Resource Management Study (ARMS) survey. In contrast,
Moschini et al. studied the welfare effects of herbicide-
tolerant soybean adoption by assuming no yield difference,
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Estimating Farm-Level Effects of Adopting
Herbicide-Tolerant Soybeans
William Lin, Gregory K. Price, and Jorge Fernandez-Cornejo1
Abstract: The farm-level effects of adopting herbicide-tolerant soybeans obtained from var-
ious data sources are compared and evaluated. In 1997, adopters’ yields were estimated to be
only 3 percent higher than for nonadopters. In the Heartland region, where about two-thirds
of U.S. s