Regime shifts and technology diffusion in crop yield growth paths with an application to maize yields in Zimbabwe

Abstract

An alternative specification for the trend component of crop yield growth is developed and applied to maize yield data for Zimbabwe's large-scale farming sector. This accounts for permanent regime shifts as new technologies are discovered but allows gradual absorption as adoption follows a diffusion path. Econometric methods are used to estimate the timing and importance of innovations, as well as the length of the diffusion path. Results from an application to Zimbabwe commercial maize yields indicate two major regime shifts that can be associated with the introduction of hybrid seed varieties, and a diffusion path that extends over a decade.