This paper estimates the on-farm impacts of adopting herbicide-tolerant soybean on herbicide use, yields, and farm profits, using an econometric model that corrects for self-selection and simultaneity and is consistent with profit maximization. The model is estimated using nationwide farm-level survey data for 1997. Given that the use of herbicide-tolerant soybeans involves the substitution of a particular herbicide—primarily glyphosate—for other herbicides, we explicitly consider this substitution process in the model.
