A model of optimal dynamic agricultural supply is derived and fitted assuming farmers have two annual stochastic crop production activities, a joint limitation on production capacity, interdependencies between past acreage utilization and current productivity, and rational expectations. A five-equation specification is fitted to annual data, 1948–80. Estimated parameters are consistent with the theory, and the model simulates well. The long-run price elasticity of corn acreage is 0.2, which is similar to those obtained from ad hoc dynamic models, but our short-run elasticities are different.