The parameters of yield response functions can vary by year. Past studiesusually assume yield functions are nonstochastic or “limited” stochastic. Inthis study, we estimate rye–ryegrass yield functions in which all parametersare random. The three functional forms considered are the linear responseplateau, the quadratic, and the Spillman-Mitscherlich. Nonstochastic yieldmodels are rejected in favor of stochastic parameter models. Quadraticfunctional forms fit the data poorly. Optimal nitrogen applicationrecommendations are calculated for the linear response plateau andSpillman-Mitscherlich. The stochastic models lead to smaller recommendedlevels of nitrogen, but the economic benefits of using fully stochastic cropyield functions are small because expected profit functions are relativelyflat for the stochastic yield functions. Stochastic crop yield functionsprovide a way of incorporating production, uncertainty into inputdecisions.
