A comparison of alternative crop response models

Three parsimonious models are hypothesized to represent corn yield response to nitrogen and phosphorus. Each model imposes specific restrictions with regard to the elasticity of factor substitution and growth plateau. Nonnested hypothesis tests are used to evaluate the competing hypotheses. The results support the restrictions imposed by the Mitscherlich-Baule model. For these data, corn response is characterized by limited substitution between nitrogen and phosphorus and a growth plateau. Further, the cost of using optimal input levels implied by the Mitscherlich-Baule if it were not "true" is small relative to the other parsimonious forms and a translog approximation.